ZeroAvia says electric efficiency, fewer repairs, and onsite hydrogen production can make zero-emissions flight cheaper than burning jet-fuel
New satellite sensor data, combined with info from the terrestrial U.S. National Lightning Detection Network, will help scientists identify the most dangerous lightning strikes
In the time it takes to read this sentence, lightning will strike somewhere in the world. In fact, lightning strikes are thought to occur between 50 and 100 times every second. Most of the time, lightning just puts on a pretty show. But sometimes, it kills people. And then there are the times when it ignites wildfires or damages electrical equipment.
With new tools, researchers can now distinguish the most damaging lightning strikes from the many millions of others that occur every year. All lightning is dangerous—but if we can tell which strikes are more likely to actually inflict harm, that information might help us react more quickly during a storm.
Already, the U.S. National Lightning Detection Network keeps a record of virtually all lightning that strikes the ground anywhere in the United States. That network is maintained by Helsinki-based Vaisala, which built it 30 years ago and sells the data to the National Weather Service and to utilities, airports, seaports, mines, and sporting arenas. Vaisala operates a global lightning detection network, as well.
But the company hasn’t been able to make one specific measurement that could provide clues as to how dangerous a given strike is likely to be—until now.
New satellite sensor data, combined with info from the terrestrial U.S. National Lightning Detection Network, will help scientists identify the most dangerous lightning strikes
Post Syndicated from Payal Dhar original https://spectrum.ieee.org/energywise/aerospace/aviation/rooftop-solar-refinery-produces-carbonneutral-fuels
Scientists in Switzerland have demonstrated a technology that can produce kerosene and methanol from solar energy and air
Scientists have searched for a sustainable aviation fuel for decades. Now, with emissions from air traffic increasing faster than carbon-offset technologies can mitigate them, environmentalists worry that even with new fuel-efficient technologies and operations, emissions from the aviation sector could double by 2050.
But what if, by 2050, all fossil-derived jet fuel could be replaced by a carbon-neutral one made from sunlight and air?
In June, researchers at the Swiss Federal Institute of Technology (ETH) in Zurich demonstrated a new technology that creates liquid hydrocarbon fuels from thin air—literally. A solar mini-refinery—in this case, installed on the roof of ETH’s Machine Laboratory—concentrates sunlight to create a high-temperature (1,500 degrees C) environment inside the solar thermochemical reactor.
Cape Air recently ordered the Eviation “Alice” battery-powered, 9-seat regional aircraft—pointing toward aviation’s e-future
Commercial electric aviation took its first steps forward last month when a Massachusetts-based regional airline announced the first order of the first all-electric passenger airplane. The “Alice,” a three-engine, battery powered airplane with a 1000-kilometer range on a single charge, is slated to be delivered to Cape Air airlines for passenger flights in 2022.
The Alice, manufactured by Kadima, Israel-based startup company Eviation, has not yet been certified by the U.S. Federal Aviation Administration. However, the company’s e-airplane “could be certified right now to fly,” insists Lior Zivan, Eviation’s CTO. “It does not need a major rewrite of the rules to get this in the air,” he says.
Zivan says the company is “anticipating full certification by 2022.”
The Alice, Zivan says, will be powered by a 900-kilowatt-hour (kWH) lithium ion battery manufactured by South Korean battery maker Kokam Battery. (For comparison, the Tesla Model 3 electric car uses a 50- to 75-kWH battery pack, according to a 2017 investor call from company CEO Elon Musk.)
Cape Air is a Northeast regional airline that flies to Cape Cod, Martha’s Vineyard, Nantucket, and numerous other vacation and regional destinations. According to Trish Lorino, Cape Air vice president of marketing and public relations, the company’s historic order of Eviation’s Alice aircraft “makes sense for us because we are a short-haul carrier.” Lorino notes that, “For 30 years, we have specialized in serving short-haul routes, particularly to niche and island destinations.”
According to Cape Air’s website, the carrier currently operates 88 Cessna 402s (which seat 6 to 10 passengers) and 4 Islander planes (9-seat capacity) made by the British company Britten-Norman. The 9-seater Alice e-aircraft thus fits within the Cape Air fleet’s general size and passenger capacity.
Lorino says that although the carrier has not yet decided which routes will feature the Alice, company officials currently anticipate that e-flights will cover routes that keep the plane close to the company’s Massachusetts headquarters. “Short-haul routes ‘in our backyard’ such as Nantucket, Martha’s Vineyard, and Provincetown would be the likely routes,” she says.
Bar-Ohay’s remarks at the Show highlighted the differences inherent in designing and engineering an all-electric airplane and a conventional, petroleum-fueled plane. As he pointed out, the Alice has a maximum takeoff weight of 6,350 kilograms (14,000 pounds), but 3,700 kg of that is the battery. (And of course there is no fuel burned, so its takeoff weight is more or less its landing weight.)
Each of the Alice’s three motors, according to Zivan, has one moving part. “A similar [petroleum-fueled] reciprocating engine has about 10: six pistons, a crankshaft, oil pump, and a two-shaft gearbox,” Zivan says. “Obviously, electric propulsion has a major advantage in both reliability and maintenance.”
There are redundant systems in the Alice, Zivan says, in both the propulsion and the battery assembly. The e-aircraft’s three engines (two “pusher” motors mounted at the rear ends of the two wingtips and another “pusher” motor mounted at the rear of the plane) have, he says, “mostly dual and for some components triple [redundancy].”
As for the electrical system, Zivan says, “The battery assembly is redundant in many levels, starting at the parallelism of the cells and ending at the number of in-series cells branches. The battery is designed in such a way that any malfunction or failure will result in a minimal reduction in the capacity if any.”
Because Alice doesn’t burn any fuel in flight, and relies only on cheaper electric charge, the cost of operating the plane is expected to be lower than its petroleum-fueled counterparts. And the noise emitted by a plane with no internal combustion engines is also lower; this is especially true for Alice, given its ability (unique to e-aircraft) to vary its propeller speeds to compensate for crosswinds and to lower cabin noise.
As an early standard-bearer in electric passenger flight, Cape Air says its decision to purchase Alice (the number of electric aircraft that will join its fleet has not been finalized) was also partly motivated by the company’s “deep sense of social responsibility,” Lorino says. (The company’s headquarters is 100-percent solar powered, she says, and the company is now hoping to use sustainable energy sources for charging its fleet of e-airplanes.)
“Our hope is that electric-powered flight is a reality in the next decade and that there is adoption from the public to view this as a viable, natural form of transportation,” she says.
Post Syndicated from Mark Harris original https://spectrum.ieee.org/tech-talk/aerospace/satellites/ubiquitilinks-satellite-phone-service
Satellite start-up UbiquitiLink’s patented technology allows ordinary cellphones to use satellites like cell towers, bringing cheap messaging to millions
“Tens of thousands of people every year die because they have no connectivity,” says Charles Miller, CEO of satellite communications start-up UbiquitiLink. “That is coming to an end.”
It’s a bold claim from a young start-up that has only a launched a single experimental satellite to date, but Miller insists that UbiquitiLink has developed technology that enables everyday cellphones to communicate directly with satellites in orbit.
If true, this could enable a cheap and truly global messaging service without the need for expensive extra antennas or ground stations. For example, Miller points out that fishing is the one of the most dangerous industries in the world, with communications failures contributing to many of its over 20,000 deaths each year.
“Around the world, most fisherman can’t afford a satellite phone,” says Miller. “They’re living on the edge already. Now with the phone in their pocket that they [already own], they can get connected.”
The received wisdom has been that cellphones lack the power and sensitivity to communicate with satellites in orbit, which are in any case moving far too fast to form useful connections.
UbiquitiLink engineers tackled one problem at a time. For a start, they calculated that cellphones should—just—have enough power to reach satellites in very low earth orbits of around 400 kilometers, as long as they used frequencies below 1 GHz to minimize atmospheric attenuation. Messages would be queued until a satellite passes overheard—perhaps once a day at first, rising to hourly as more satellites are launched.
Satellites would use the same software found in terrestrial cell towers, with a few modifications. Signals would be Doppler shifted because of the satellite’s high velocity (around 7.5 kilometers/second).
“You have to compensate so that the phone doesn’t see that Doppler shift, and you have to trick the phone into accepting the time delay from the extra range,” says Miller. “Those two pieces are our secret sauce and are patented. The phone just thinks [the satellite is] a weak cell tower at the edge of its ability to connect to, but it tolerates that.”
UbiquitiLink also brushes off concerns about interference. In a filing with the FCC, the company noted that the downlink signal from its satellite “is very low and is intended to be the ‘tower of last resort.’” In cities, the satellite’s broadcasts would be drowned out by powerful urban cell towers, while in areas with no cell coverage at all, there is nothing to interfere with.
It is only in rural or suburban areas, with spare and widely separated towers, that interference is a potential concern. Even there, wrote UbiquitiLink, the design of cellular networks, and the fact that the satellite uses time-sharing protocols, means just a 0.0000117 percent of a conflict, which would last only a very short time.
The technology has already been tested. In February, an experimental satellite briefly connected with cellular devices in New Zealand and the Falkland Islands before a computer on board failed. “This limited our ability to test but we got enough data to demonstrate the key fundamentals we couldn’t from the ground,” says Miller.
UbiquitiLink is now planning to try again. In a few days, its latest orbital cell tower will launch on board a SpaceX resupply mission to the International Space Station. Later this summer, the payload will be attached to a Cygnus capsule that brought supplies on a previous mission. When the capsule is jettisoned for its return to Earth, UbiquitiLink’s device will piggyback on it, hopefully for six months, testing 2G and LTE cell connections with wireless operators in up to a dozen countries.
Miller says UbiquitiLink has trial agreements with nearly 20 operators around the world, and plans to operate a basic messaging service in 56 countries. “From their perspective, we’re a roaming provider that extends their network everywhere. They keep the customer relationship and we’re just a wholesale provider. It’s a win-win relationship,” he says.
This week, the company also raised another $5.2 million in funding from venture capital firm run by Steve Case, co-founder of AOL, bring its total capitalization to over $12 million.
If these tests go well, UbiquitiLink wants to start launching operational satellites next year, with plans for several thousand satellites by 2023. Today’s smartphones could connect to UbiquitiLink’s satellites by simply downloading an app, and even a handful could provide a useful service, says Miller: “With 3 to 6 microsatellites, we can provide global coverage everywhere between +55 and -55 degrees latitude several times a day. Not all the 5 billion people with a phone will want to use that. But even if just one in a hundred thinks a periodic service is good enough, that’s still 50 million people.”
Beyond emergency messaging, UbiquitiLink is targeting internet of things users who might balk at buying additional hardware. “Most cars come off the assembly line today with a cellular chip already installed, for security or over the air updates,” says Miller. “Those cars will now stay connected everywhere.”
If UbiquitiLink’s technology works at scale, it could undercut other satellite start-ups, like Swarm, that are pinning their hopes on selling millions of earth stations for IoT. But UbiquitiLink is not shunning traditional satellites completely. The test device launching this weekend will use rival Globalstar’s satellites for telemetry, tracking and control.
Post Syndicated from Eliza Strickland original https://spectrum.ieee.org/aerospace/space-flight/three-steps-to-a-moon-base
Space agencies and private companies are working on rockets, landers, and other tech for lunar settlement
In 1968, NASA astronaut Jim Lovell gazed out of a porthole from lunar orbit and remarked on the “vast loneliness” of the moon. It may not be lonely place for much longer. Today, a new rush of enthusiasm for lunar exploration has swept up government space agencies, commercial space companies funded by billionaires, and startups that want in on the action. Here’s the tech they’re building that may enable humanity’s return to the moon, and the building of the first permanent moon base.
1. Getting to the Moon
Super-Heavy-Lift Rockets: NASA is relying on the Space Launch System (SLS) for its 2024 lunar return plan—although the rocket is over budget and behind schedule. China is working to upgrade its current Long March 5 rocket (which failed in its second flight) to the Long March 9. Russia says it has finalized the design for its Yenisei rocket, but experts wonder if it will actually get built. Blue Origin and SpaceX’s rockets use reusable stages, which could make them much more economical. SpaceX’s Starship is the most futuristic of the lot, comprised of reusable stages and a built-in crew capsule.
2. Landing on the Moon
Landers: NASA has pushed for lunar cargo landers by working with companies [in blue brackets] in its Commercial Lunar Payload Services program. In May, its first contracts went to Astrobotic Technology, Intuitive Machines, and OrbitBeyond. But NASA’s work with companies developing crewed landers has only just begun. China’s Chang’e 5 is scheduled to blast off on a sample return mission in December. Blue Origin’s lander could be converted to a crewed vehicle.
3. Building on the Moon
Once we manage to get humans and their gear to the lunar surface, what happens next? Many companies and researchers are actively pursuing technology projects that will enable a permanent settlement on the moon. Here are a few that we find particularly interesting.
Habitats: The European Space Agency is funding architectural and engineering work for the Moon Village, its proposed cooperative international settlement. See: “Engineers and Architects Are Already Designing Lunar Habitats.”
Science: Astrophysicists at the NASA-funded Network for Exploration and Space Science have a plan for a radio observatory on the moon’s far side. See: “Rovers Will Unroll a Telescope on the Moon’s Far Side.”
Navigation: For precision landings and safe exploration, Astrobotic Technology and Draper Labs have both devised cutting-edge mapping software. See: “Robots Will Navigate the Moon With Maps They Make Themselves.”
Post Syndicated from Susan Hassler original https://spectrum.ieee.org/aerospace/space-flight/humanitys-lunar-habitats
A look at current plans to return to the moon…and stay there
The 50th anniversary of the first human moon landing is upon us (20 July, to be exact). This roughly 772,000-kilometer round-trip expedition is being celebrated all year long—books, movies, commemorative magazine issues, and special events abound.
In May, IEEE gave its President’s Award to the remarkable and indomitable Katherine Johnson, who helped calculate, by hand, the trajectory for the Apollo 11 lunar landing mission. If you have US $9 million dollars to spare, you can drop by Christie’s in New York City on 18 July to bid in the auction of Apollo 11’s Lunar Module Timeline Book, with its three-hole-punched pages and hand-checked flight plan. Don helmet and gloves—check. Test cabin regulator—check.
In case you’ve managed to miss what all the fuss is about: On 20 July 1969, NASA’s Neil Armstrong and Buzz Aldrin landed on the moon, while Command Module Pilot Michael Collins circled above them with their ride home. It was the culmination of years of human effort, interrupted by delays, setbacks, and the assassination of U.S. president John F. Kennedy in 1963. The mission was carried out as the Vietnam War, the war on poverty, and the civil rights and women’s movements were all in full swing.
As the Apollo 11 retrospective swirls around us, we’ve decided to take a look at today’s efforts to return to the moon, and this time, to build habitable lunar bases. What will it take? Which rockets and landers will get us there? Dive into the tech that will enable humanity’s first space settlement in our special report: Project Moon Base.
Traveling to the moon is hard enough, but attempting to live on the lunar surface presents even greater challenges. It’s been compared with living in an Antarctic research station or on a nuclear submarine that remains submerged for months on end.
The moon, for all its luminescent beauty on sultry summer evenings or frosty winter nights, is one mean rock to live on. It has no atmosphere, little gravity, and cuttingly abrasive sand. The surface is blasted by cosmic radiation and is, every lunar day, both extremely hot and extremely cold. There is water at its poles, but it’s frozen. Yet the engineers and architects designing moon habitats are confident that they can overcome these and other sobering challenges, as you’ll see in “Engineers and Architects Are Already Designing Lunar Habitats.”
Despite short bursts of excitement about moon landings and space-shuttle flights, antipathy about human space travel has coexisted with enthusiasm for it since the first humans escaped gravity’s shackles in the early 1960s. Why are we spending time, money, and energy to send ourselves into space, while there are so many problems to take care of here on Planet Earth?
People forget that pictures of Earth, taken from the moon, helped spur the modern environmental movement. I think about what the Chinese artist Ai Weiwei said, commenting on the plans of Japanese billionaire Yusaku Maezawa to bring artists with him on SpaceX’s first trip around the moon: “Without knowing other celestial bodies, we cannot truly understand what our own planet is about.”
This article appears in the July 2019 print issue as “Home, Sweet Moon?”
Post Syndicated from Eliza Strickland and Glenn Zorpette original https://spectrum.ieee.org/aerospace/space-flight/the-great-moon-rush
NASA and its partners are already building the rockets and habitat, navigation, and communication systems that will let people live in lunar colonies indefinitely
Fifty years ago this month, two people walked on the moon. It was by any measure a high point in human history, an achievement so pure and glorious that for a moment, anyway, it seemed to unite the world’s fractious, cacophonous communities into a kind of triumphant awe. Over the next three and a half years, 10 more people had the honor of leaving tracks on another world. And then it all came to a halt.
It’s time to go back, and this time for a lot more than a series of multibillion-dollar strolls.
After decades of scattered objectives and human missions that literally went nowhere (aboard the International Space Station), the world’s space agencies are coming into surprising, if delicate, alignment about returning to the moon and building a settlement there. NASA is leading the charge, with new and aggressive backing from the White House. The U.S. space agency has officially declared its intention to return humans to the moon by 2024—although many observers question whether it can adhere to such an ambitious timetable.
So far, NASA and its partners have drawn up the most detailed plans and spent the most money. But the enthusiasm goes far beyond the United States. This past April, Zhang Kejian, director of the China National Space Administration, said the country planned to build an inhabited research station near the moon’s south pole “in about 10 years.” China has the world’s second-largest space budget behind the United States, and it has already put two landers and two rovers on the moon.
Even before China’s announcement, Russia had declared its intention to land cosmonauts on the moon in 2031 and to begin constructing a moon base in 2034. The head of the European Space Agency, meanwhile, has been promoting a concept called the Moon Village—an international settlement that would support science, business, and tourism on the lunar surface.
Regard all of these plans and dates skeptically (particularly the Russian ones), but don’t dismiss them as pipe dreams. Unlike the Apollo-era space race, this time around the rush to the moon isn’t being driven solely by space agencies and national pride. The past two decades have seen the emergence of a commercial space industry, with companies building rockets and rovers and pursuing more speculative goals. In the United States, this private-sector enterprise is fueled in part by the spacefaring visions of two famous billionaires, Jeff Bezos and Elon Musk.
NASA’s scheme for lunar exploration may have room for these companies, but the agency’s plan is very much in flux, and it has already drawn fire from experts who find it needlessly complicated. It depends on a small space station in high lunar orbit—called the Gateway—that would serve as a combination way station, storehouse, assembly facility, and laboratory for people and equipment traveling between Earth and the moon. NASA insists such a station is necessary because the spaceships it’s currently developing don’t have the propulsive capacity to go directly to low lunar orbit. The agency also says that operating the Gateway will give it deep-space experience for a crewed mission to Mars. But outsiders have attacked the idea as an unnecessary expense and an additional point of vulnerability, with one former NASA administrator going so far as to call it “stupid.” For a detailed consideration of the pros and cons, turn to “NASA’s Lunar Space Station Is a Great/Terrible Idea.”
The Gateway plan, which NASA began formulating nearly a decade ago, calls for a very large rocket to ferry people and supplies to the orbiter, as well as a fleet of landers to travel between the Gateway and the moon’s surface. The first version of the rocket, known as the Space Launch System (SLS) Block 1, is designed to carry a crewed space capsule called Orion that will weigh 23 metric tons. The SLS has been under construction for eight years by a consortium led by Boeing and including United Launch Alliance, Northrop Grumman, and Aerojet Rocketdyne. So far it has cost about US $17 billion and is three years behind schedule.
Orion, meanwhile, is being built by Lockheed Martin with help from the European Space Agency and Airbus, and is supposed to support six astronauts. The Orion partners are officially planning to launch a test mission in 2020 or 2021 (stay tuned), in which an unoccupied Orion will go into orbit around the moon and then return to Earth.
Until this past March, NASA had been aiming for a moon landing in 2028, but under pressure from the Trump White House the agency moved its target up to 2024. And that’s where the billionaires could come in. Musk’s and Bezos’s rocket companies, SpaceX and Blue Origin, are both developing heavy-lift rockets capable of reaching the moon. At its highest levels, NASA remains committed to the SLS rocket and the Gateway. Nevertheless, the agency has also sporadically flirted with the idea of Orion being lofted by SpaceX or Blue Origin rockets, which some observers insist are being developed at a swifter pace than the SLS.
Both companies seem up for the challenge: SpaceX already has a contract with NASA to build crewed spacecraft to ferry astronauts to the International Space Station. And Blue Origin is building both heavy-lift rockets and a crewed lunar lander, named Blue Moon, which Bezos says will be ready for action in 2024. Even if NASA doesn’t employ their services, it’s entirely possible that one or both of these companies will go it alone. In a feature article about Blue Origin’s BE-4, IEEE Spectrum contributor Mark Harris appraises a rocket engine that could launch a new era in space exploration.
Clearly, the establishment of a reliable and efficient system for moving cargo and crew to the moon’s surface is an enormous undertaking. Big as it will be, it won’t make much sense unless it’s just the opening act of an epic saga in which humans establish a permanent presence there. As we explain in this special report, taking up residence on the moon will involve stupendous challenges.
For example, in “Engineers and Architects Are Already Designing Lunar Habitats,” Matthew Hutson spotlights plans for dwellings that can withstand extreme temperatures, withering radiation, and moondust so abrasive it can eat through a space suit. One of the most promising building techniques uses that very dust, technically known as regolith, as raw material for 3D printers.
Navigating in the bleak lunar landscape will also be tough. With no GPS to guide them, astronauts in a rover could easily get lost in an endless ashen expanse. In “How to Keep Astronauts From Getting Lost,” we describe how space startups are solving the problem with extraordinary feats of mapping-on-the-fly. One company, Astrobotic, says its simultaneous localization-and-mapping software will also guide rocket-powered drones that will explore the moon’s lava tubes. These huge natural underground tunnels are candidates for next-generation settlements, as they offer more moderate temperatures and shielding from radiation.
To be truly sustainable, a lunar settlement will have to make use of local resources. So engineers are already designing the mining operations that will extract water ice from the regolith in the moon’s permanently shadowed craters. The infographic “Squeezing Rocket Fuel From Moon Rocks” explains how those water molecules can then be split into hydrogen and oxygen, basic components of rocket propellant.
If we master these and other challenges, we’ll be poised for a great leap. In the second half of the 20th century, as humankind began taking the idea of spaceflight seriously, a base on the moon was invariably regarded as the logical perch from which to study, and eventually spread out into, the solar system. What we learned then was that space exploration timetables are long, and political will capricious. But now, as it did in the 1960s, the United States finds itself in a fast-moving great-power rivalry. As it was then, it is inclined to a showy demonstration of technological prowess. And this time the endeavor has the backing of billionaires on a mission.
All that might just be enough to get humans back to the moon. To make a permanent home there, though, will take something more. Such as? Well, international cooperation on a scale seldom seen outside of warfare comes to mind. Our biggest comparable model of colonization is Antarctica: many separate bases, each built and maintained by a different country. It is difficult to imagine that on the moon.
Perhaps the goal of living on the moon will at last provide an objective so grand and sublime that it will unite nations that compete economically. Eventually, it might even unite ones that compete geopolitically. It would be a fitting start to humankind’s final migration.
This article appears in the July 2019 print issue as “The Coming Moon Rush.”
Astrobotic’s autonomous navigation will help lunar landers, rovers, and drones find their way on the moon
Neil Armstrong made it sound easy. “Houston, Tranquility Base here. The Eagle has landed,” he said calmly, as if he had just pulled into a parking lot. In fact, the descent of the Apollo 11 lander was nerve-racking. As the Eagle headed to the moon’s surface, Armstrong and his colleague Buzz Aldrin realized it would touch down well past the planned landing site and was heading straight for a field of boulders. Armstrong started looking for a better place to park. Finally, at 150 meters, he leveled off and steered to a smooth spot with about 45 seconds of fuel to spare.
“If he hadn’t been there, who knows what would have happened?” says Andrew Horchler, throwing his hands up. He’s sitting in a glass-walled conference room in a repurposed brick warehouse, part of Pittsburgh’s Robotics Row, a hub for tech startups. This is the headquarters of space robotics company Astrobotic Technology. In the coming decades, human forays to the moon will rely heavily on robotic landers, rovers, and drones. Horchler leads a team whose aim is ensuring those robotic vessels—including Astrobotic’s own Peregrine lander—can perform at least as well as Armstrong did.
Astrobotic’s precision-navigation technology will let both uncrewed and crewed landers touch down exactly where they should, so a future Armstrong won’t have to strong-arm her landing vessel’s controls. Once they’re safely on the surface, robots like Astrobotic’s will explore the moon’s geology, scout out sites for future lunar bases, and carry equipment and material destined for those bases, Horchler says. Eventually, rovers will help mine for minerals and water frozen deep in craters and at the poles.
Astrobotic was founded in 2007 by roboticists at Carnegie Mellon University to compete for the Google Lunar X Prize, which challenged teams to put a robotic spacecraft on the moon. The company pulled out of the competition in 2016, but its mission has continued to evolve. It now has a 20-person staff and contracts with a dozen organizations to deliver payloads to the moon, at US $1.2 million per kilogram, which the company says is the lowest in the industry. Late last year, Astrobotic was one of nine companies that NASA chose to carry payloads to the moon for its 10-year, $2.6 billion Commercial Lunar Payload Services (CLPS) program. The space agency announced the first round of CLPS contracts in late May, with Astrobotic receiving $79.5 million to deliver its payloads by July 2021.
The moon’s allure is universal, says John Horack, an aerospace engineer at Ohio State University. “The moon is just hanging in the sky, beckoning to us. That beckoning doesn’t know language or culture barriers. It’s not surprising to see so many thinking about how to get to the moon.”
On the moon, there is no GPS, compass-enabling magnetic field, or high-resolution maps for a lunar craft to use to figure out where it is and where it’s going. Any craft will also be limited in the computing, power, and sensors it can carry. Navigating on the moon is more like the wayfinding of the ancient Polynesians, who studied the stars and ocean currents to track their boats’ trajectory, location, and direction.
A spacecraft’s wayfinders are inertial measurement units that use gyroscopes and accelerometers to calculate attitude, velocity, and direction from a fixed starting point. These systems extrapolate from previous estimates, so errors accumulate over time. “Your knowledge of where you are gets fuzzier and fuzzier as you fly forward,” Horchler says. “Our system collapses that fuzziness down to a known point.”
A conventional guidance system can put a vessel down within an ellipse that’s several kilometers long, but Astrobotic’s system will land a craft within 100 meters of its target. This could allow touchdowns near minable craters, at the heavily shadowed icy poles, or on a landing pad next to a moon base. “It’s one thing to land once at a site, a whole other thing to land repeatedly with precision,” says Horchler.
Astrobotic’s terrain-relative navigation (TRN) sensor contains all the hardware and software needed for smart navigation. It uses 32-bit processors that have worked well on other missions and FPGA hardware acceleration for low-level computer-vision processing. The processors and FPGAs are all radiation hardened. The brick-size unit can be bolted to any spacecraft. The sensor will take a several-megapixel image of the lunar surface every second or so as the lander approaches. Algorithms akin to those for facial recognition will spot unique features in the images, comparing them with stored maps to calculate lunar coordinates and orientation.
Those stored maps are a computing marvel. Images taken by NASA’s Lunar Reconnaissance Orbiter (LRO), which has been mapping the moon since 2009, have very different perspectives and shadows from what the lander will see as it descends. This is especially true at the poles, where the angle of the sun changes the lighting dramatically.
So software wizards at Astrobotic are creating synthetic maps. Their software starts with elevation models based on LRO data. It fuses those terrain models with data on the relative positions of the sun, moon, and Earth; the approximate location of the lander; and the texture and reflectiveness of the lunar soil. Finally, a physics-based ray-tracing system, similar to what’s used in animated films to create synthetic imagery, puts everything together.
Horchler pulls up two images of a 50-by-200-kilometer patch near the moon’s south pole. One is a photo taken by the LRO. The other is a digitally rendered version created by the Astrobotic software. I can’t tell them apart. Future TRN systems may be able to build high-fidelity maps on the fly as the lander descends, but that’s impossible with current onboard computing power, Horchler says.
To confirm the TRN’s algorithms, Astrobotic has run tests in the Mojave Desert. A 2014 video shows the TRN sensor mounted on a vertical-takeoff-and-landing vehicle made by Masten Space Systems, another company chosen for NASA’s CLPS program. Astrobotic engineers had mapped the scrubby area beforehand, including a potential landing site littered with sandbags to mimic large rocks. In the video, the vehicle takes off without a programmed destination. The navigation sensor scans the ground, matching what it sees to the stored maps. The hazard-detection sensor uses lidar and stereo cameras to map shapes and elevation on the rocky terrain and track the lander’s distance to the ground. The craft lands safely, avoiding the sandbags.
Astrobotic expects its first CLPS mission to launch in July 2021, aboard a United Launch Alliance Atlas V rocket. The 28 payloads aboard the stout Peregrine lander will include NASA scientific instruments, another scientific instrument from the Mexican Space Agency, rovers from startups in Chile and Japan, and personal mementos from paying customers.
In a space that Astrobotic employees call the Tiger’s Den, a large plush tiger keeps an eye on aerospace engineer Jeremy Hardy, who looks like he’s having too much fun. He’s flying a virtual drone onscreen through a landscape of trees and rocks. When he switches to a drone’s-eye view, the landscape fills with green dots, each a unique feature that the drone is tracking, like a corner or an edge.
The program Hardy is using is called AstroNav, which will guide propulsion-powered drones as they fly through the moon’s immense lava tubes. These temperature-stable tunnels are believed to be tens of kilometers long and “could fit whole cities within them,” Horchler says. The drones will map the tunnels as they fly, coming back out to recharge and send images to a lunar station or to Earth.
Hardy’s drone is flying in unchartered territory. AstroNav uses a simultaneous localization and mapping (SLAM) algorithm, a heavyweight technology also used by self-driving cars and office delivery robots to build a map of their surroundings and compute their own location within that map. AstroNav blends data from the drone’s inertial measurement units, stereo-vision cameras, and lidar. The software tracks the green-dotted features across many frames to calculate where the drone is.
The company has tested AstroNav-guided hexacopters in West Virginian caves, craters in New Mexico, and the Lofthellir lava tube of Iceland. Similar SLAM techniques could guide autonomous lunar rovers as they explore permanently shadowed regions at the poles.
Astrobotic has plenty of competition. Another CLPS contractor is Draper Laboratory, which helped guide Apollo missions. The lab’s navigation system, also built around image processing and recognition, will take Japanese startup Ispace’s lander to the moon.
Draper’s “special sauce” is software developed for the U.S. Army’s Joint Precision Airdrop System, which delivers supplies via parachute in war zones, says space systems program manager Alan Campbell. Within a box called an aerial guidance unit is a downward-facing camera, motors, and a small computer running Draper’s software. The software determines the parachute’s location by comparing terrain features in the camera’s images with commercial satellite images to land the parachute within 50 meters of its target.
The unit also uses Doppler lidar, which detects hazards and measures relative velocity. “When you’re higher up, you can compare images to maps,” says Campbell. At lower altitudes, a different method tracks features and how they’re moving. “Lidar will give you a finer-grain map of hazards.”
Draper’s long experience dating back to Apollo gives the lab an edge, Campbell adds. “We’ve landed on the moon before, and I don’t think our competitors can say that.”
Other nations with lunar aspirations are also relying on autonomous navigation. China’s Chang’e 4, for example, became the first craft to land on the far side of the moon, in early January. In its landing video, the craft hovers for a few seconds above the surface. “That indicates it has lidar or [a] camera and is taking an image of the field to make sure it’s landing on a safe spot,” says Campbell. “It’s definitely an autonomous system.”
Israel’s lunar spacecraft Beresheet was also expected to make a fully automated touchdown in April. It relied on image-processing software run on a computer about as powerful as a smartphone, according to reports. However, just moments before it was to land, it crashed on the lunar surface due to an apparent engine failure.
In the race to the moon, there will be no one winner, Ohio State’s Horack says. “We need a fair number of successful organizations from around the world working on this.”
Astrobotic is also looking further out. Its AstroNav could be used on other cosmic bodies for which there are no high-resolution maps, like the moons of Jupiter and Saturn. The challenge will be scaling back the software’s appetite for computing power. Computing in space lags far behind computing on Earth, Horchler notes. Everything needs to be radiation tolerant and designed for a thermally challenging environment. “It tends to be very custom,” he says. “You don’t have a new family of processors every two years. An Apple Watch has more computing power than a lot of spacecraft out there.”
The moon will be a crucial test-bed for precision landing and navigation. “A lot of the technology that it takes to land on the moon is similar to what it takes to land on Mars or icy moons like Europa,” Horchler says. “It’s much easier to prove things out at our nearest neighbor than at bodies halfway across the solar system.”
This article appears in the July 2019 print issue as “Turn Left at Tranquility Base.”
Post Syndicated from Stephen Cass original https://spectrum.ieee.org/aerospace/astrophysics/rovers-will-unroll-a-telescope-on-the-moons-far-side
Astronomers need a quiet place to observe the cosmic dawn
For decades, astronomers have gazed up at the moon and dreamed about what they would do with its most unusual real estate. Because the moon is gravitationally locked to our planet, the same side of the moon always faces us. That means the lunar far side is the one place in the solar system where you can never see Earth—or, from a radio astronomer’s point of view, the one place where you can’t hear Earth. It may therefore be the ideal location for a radio telescope, as the receiver would be shielded by the bulk of the moon from both human-made electromagnetic noise and emissions from natural occurrences like Earth’s auroras.
Early plans for far-side radio observatories included telescopes that would use a wide range of frequencies and study many different phenomena. But as the years rolled by, ground- and satellite-based telescopes improved, and the scientific rationale for such lunar observatories weakened. With one exception: A far-side telescope would still be best for observing phenomena that can be detected only at low frequencies, which in the radio astronomy game means below 100 megahertz. Existing telescopes run into trouble below that threshold, when Earth’s ionosphere, radio interference, and ground effects begin to play havoc with observations; by 30 MHz, ground-based observations are precluded.
In recent years, scientific interest in those low frequencies has exploded. Understanding the very early universe could be the “killer app” for a far-side radio observatory, says Jack Burns, an astrophysics professor at the University of Colorado and the director of the NASA-funded Network for Exploration and Space Science. After the initial glow of the big bang faded, no new light came into the universe until the first stars formed. Studying this “cosmic dawn [PDF],” when the first stars, galaxies, and black holes formed, means looking at frequencies between 10 and 50 MHz, Burns says; this is where signature emissions from hydrogen are to be found, redshifted to low frequencies by the expansion of the universe.
With preliminary funding from NASA, Burns is developing a satellite mission that will orbit the moon and observe the early universe while it travels across the far side. But to take the next step scientifically requires a far larger array with thousands of antennas. That’s not practical in orbit, says Burns, but it is feasible on the far side. “The lunar surface is stable,” he says. “You just put these things down. They stay where they need to be.”
This article appears in the July 2019 print issue as “The View From the Far Side.”
Post Syndicated from David Schneider original https://spectrum.ieee.org/aerospace/robotic-exploration/squeezing-rocket-fuel-from-moon-rocks
Here’s how lunar explorers will mine the regolith to make rocket fuel
The most valuable natural resource on the moon may be water. In addition to sustaining lunar colonists, it could also be broken down into its constituent elements—hydrogen and oxygen—and used to make rocket propellant.
Although the ancients called the dark areas on the moon maria (Latin for “seas”), it has long been clear that liquid water can’t exist on the lunar surface, where it would swiftly evaporate. Since the 1960s, though, scientists have hypothesized that the moon indeed harbors water, in the form of ice. Because the moon has a very small axial tilt—just 1.5 degrees—the floors of many polar craters remain in perpetual darkness. Water could thus condense and survive in such polar “cold traps,” where it might one day be mined.
In a cavernous building in Washington state, Blue Origin workers are constructing New Glenn’s BE-4 engine
Jeff Bezos, the founder of Amazon and the richest person on Earth, is of course a man who thinks big. But exactly how big is only now becoming clear.
“The solar system can support a trillion humans, and then we’d have 1,000 Mozarts, and 1,000 Einsteins,” he told a private aviation group at the Yale Club in New York City this past February. “Think how incredible and dynamic that civilization will be.” The pragmatic entrepreneur went on to say that “the first step [is] to build a low-cost, highly operable, reusable launch vehicle.” And that’s precisely what he is doing with his private aerospace firm, Blue Origin.
Blue Origin is not just a company; it’s a personal quest for Bezos, who currently sells around US $1 billion of his own Amazon stock each year to fund Blue Origin’s development of new spacecraft. The first, called New Shepard, is a suborbital space-tourist vehicle, which should make its first crewed flight later this year. But it is the next, a massive rocket called New Glenn, that could enable cheap lunar missions and kick-start Bezos’s grand vision of human beings living all over the solar system.
New Glenn’s first stage will use seven enormous new BE-4 engines, each powered by methane (the same fuel used in some of Amazon’s less-polluting delivery vans in Europe). Like SpaceX’s Falcon booster, the New Glenn’s first stage will also use its engines to steer itself gracefully back down to a landing ship for reuse.
After eight years of development, the BE-4 represents the cutting edge of rocket science. It promises to be simpler, safer, cheaper, and far more reusable than the engines of yesteryear.
Blue Origin is also working on two other engines, including one (the BE-7) destined for the company’s Blue Moon lunar lander. But the BE-4 is the largest of the three, designed to generate as much as 2,400 kilonewtons of thrust at sea level. That’s far less than the 6,770 kN provided by each of the five F-1 engines that sent men to the moon a half century ago. Even so, 2,400 kN is quite respectable for a single engine, which in multiples can produce more than enough oomph for the missions envisioned. For comparison, the Russian RD-171M engine provides a thrust of 7,257 kN, and Rocketdyne’s RS-68A, which powers the Delta IV launch vehicle, can generate 3,137 kN.
But the real competition now arguably comes from the other swashbuckling billionaire in the United States’ new space race: Elon Musk. His aerospace company, SpaceX, is testing a big engine called Raptor, which is similarly powered by liquid methane and liquid oxygen. Although the Raptor is slightly less powerful, at 1,700 kN, it is destined for an even larger rocket, the Super Heavy, which will employ 31 of the engines, and the Starship spacecraft, which will use 7 of them.
With SpaceX working at a blistering pace on various space missions and the oft-delayed BE-4 still two years from its first flight, Bezos could find his futuristic engine overshadowed before it begins launching payloads into orbit. Even so, Bezos’s new rocket engine could prove more reliable and less costly than its rivals, which would make it enormously influential in the long run.
Every aspect of the BE-4’s design can be traced back to Bezos’s requirements of low cost, reusability, and high operability.
The overwhelming majority of orbital rocket engines ever made, typically costing millions of dollars apiece, have been used just once, ending up on the bottom of the sea or scattered over a desert. That single-shot approach makes about as much sense, Musk likes to say, as scrapping a 747 airliner after every flight.
The space shuttle was supposed to change all that, combining two reusable boosters with an orbiter housing three main engines that could be flown over and over again. But the shuttle proved far different from the workhorse it was intended to be, requiring painstaking evaluation and reconstruction after every flight. As a result, each shuttle mission cost an estimated $450 million. Riffing on Musk’s airliner analogy, Bezos said recently, “You can’t fly your 767 to its destination and then X-ray the whole thing, disassemble it all, and expect to have acceptable costs.”
In the end, Blue Origin took inspiration for the BE-4 not from the U.S. space program but from the program’s archrival, that of the Soviets.
As far back as 1949, Soviet engineers started adopting staged combustion engines, where some fuel and oxidizer flows first through a preburner before reaching the main combustion chamber. That preburn is greatly restricted, providing just enough pressure increase to drive the turbines that pump fuel and oxidizer into the combustion chambers. This scheme is more efficient than those used in simpler engines in which some propellant is burned just to drive the engine’s pumps. In that case, the hot gases that result are vented, which squanders the energy left in them. In their designs, Russian engineers focused on a type of staged combustion that uses a high ratio of oxidizer to fuel in the preburner and delivers exceptional thrust-to-weight performance.
American engineers considered this approach to be impractical because high levels of hot, oxygen-rich gases from the preburner would attack and perhaps even ignite metallic components downstream. They opted instead to develop “fuel-rich” preburner technology, which doesn’t have this problem because the hot gases leaving the preburner contain little oxygen. American engineers used this approach, for example, in the shuttle’s main engines.
The Soviets persevered, using oxygen-rich staged combustion in an engine called the NK-33 for the USSR’s secret moon-shot program in the late 1960s. The result of that program, a powerful but ungainly rocket called the N1, suffered a series of spectacular launchpad failures and never reached orbit. Dozens of NK-33s were mothballed in a warehouse until the mid-1990s, when the U.S. engine company Aerojet bought them to study and rebuild.
By the time Blue Origin started work on the BE-4 in 2011, American rocket engineers were ready to take on the challenges of oxygen-rich staged combustion to achieve the higher efficiency it offered. So that’s what Blue Origin decided to use in this new rocket engine. SpaceX, too, will have an oxygen-rich preburner in its Raptor engines, which will also have a fuel-rich preburner, a configuration known as full-flow staged combustion.
As the Soviets learned vividly with the N1, complexity is the enemy of reliability—even more so when an engine needs to be reused many times. “Fatigue is the biggest issue with a reusable engine,” says Tim Ellis, a propulsion engineer who worked on the BE-4 from 2011 to 2015. “Rocket engines experience about 10 times more stress, thrust, and power than an aircraft engine, so it’s a much harder problem.”
To help solve that problem, Ellis suggested incorporating 3D-printed metal parts into the BE-4. Using 3D printing accelerated the design process, replacing cast or forged parts that used to take a year or more to source with parts made in-house in just a couple of months. The technology also allowed intricately shaped components to be made from fewer pieces.
“Fewer parts means fewer joints, and joints are one of the areas that can fatigue more than anything else,” says Ellis. The 3D metal printing process involves sintering metal powders with lasers, and the resulting material can end up even stronger than traditional machined or cast components. Ellis estimates that up to 5 percent of Blue Origin’s engine by mass could now be 3D printed.
“True operational reusability is what we have designed to from day one,” says Danette Smith, Blue Origin’s senior vice president of Blue Engines, in an interview over email. Each BE-4 should be able to fly at least 25 times before refurbishment, according to Bezos. When the expense of building each engine can be shared over dozens of flights, running costs become more important.
Blue Origin and SpaceX have both settled on methane for fueling their new engines, but for different reasons. For Musk, methane meshes with his interplanetary ambitions. Methane is fairly simple to produce from just carbon dioxide and water, both to be found on Mars. A spaceship powered by methane engines could theoretically manufacture its own fuel on Mars for a journey back to Earth or to other destinations in the solar system.
Blue Origin’s choice was driven by more pragmatic concerns, says Rob Meyerson, president of Blue Origin from 2003 to 2018: “We found that LNG [liquefied natural gas] you could buy right out of the pipeline is four times cheaper than rocket-grade kerosene,” a more traditional fuel choice. Unlike gaseous methane, which often contains high levels of impurities, LNG is 95 percent pure methane, says Meyerson. Methane is also less toxic than kerosene and is stored at temperatures similar to those used for liquid oxygen, making refueling simpler and safer.
For all of Blue Origin’s technical prowess, media headlines might suggest that it’s losing this new space race. Virgin Galactic astronauts have flown the company’s suborbital vehicle to space twice, and SpaceX has delivered cargo more than 70 times to Earth orbit and beyond. Blue Origin, meanwhile, is still tinkering with the uncrewed New Shepard and carrying out seemingly interminable ground tests of the BE-4.
But saying Blue Origin is lagging is to misunderstand its mission, says John Horack, professor of aerospace policy at Ohio State University: “Their motto is Gradatim Ferociter—to be ferociously incremental, as opposed to making spectacular leaps forward. Test, test, test. Data, data, data. Improve and then do it all again.”
Most of Blue Origin’s engine and flight tests are carried out on a remote ranch in West Texas, far from prying eyes. The only mishaps that are publicly known are a prototype launch vehicle crashing there in 2011, a booster failure on return in 2015, and a BE-4 exploding on a test stand in 2017.
“If they were funded differently, there would be a need to demonstrate milestone after milestone,” says Horack. “But because they’re funded through Mr. Bezos’s personal wealth, they can afford that strategy. And I think that in the end it will pay off handsomely.”
Arguably, it already has. In 2014, rival launch provider United Launch Alliance (ULA) was looking for an engine for its own next-generation launch vehicle, the Vulcan. It offered to invest in the BE-4 program, but only if Blue Origin could increase the engine’s planned thrust by nearly 40 percent. For Blue Origin, that would mean not only taking the BE-4 back to the drawing board but redesigning the entire New Glenn rocket to match, likely delaying its maiden launch by years. Worse still, there was no guarantee that ULA would end up buying any BE-4s at all.
For Meyerson, then Blue Origin president, the opportunity to power two new launch vehicles, potentially for a decade or more to come, was worth the risk. “There’s not a lot of new rockets,” he says. “It’s not like the automobile industry, where companies are designing and building new cars every year.”
Last September, that gamble finally paid off as ULA confirmed that the Vulcan would use a pair of BE-4 engines. Just weeks later, the U.S. Air Force announced hundreds of millions of dollars in funding for both the Vulcan and the New Glenn to support future military launches. “It’s brilliant, because Blue Origin found a way to monetize something they had to do anyway,” says Horack. “The more engines you make, the lower your unit cost, the more flight data you get, and the more reliability you can build in. It’s a virtuous cycle.”
ULA’s decision also cleared the way for Blue Origin to start work on a planned BE-4 factory in Huntsville, Ala. Groundbreaking for the $200 million facility began in January. The company already has a factory to build and refurbish New Glenn rockets near the Kennedy Space Center, in Florida. The first New Glenn and BE-4s could lift off at Cape Canaveral as soon as 2021.
Blue Origin would be well advised to keep to that schedule. Gradatim Ferociter is a great motto for a billionaire’s passion project. But for a rapidly growing business that needs to compete in the race to return to the moon, Blue Origin might need to be a little less gradatim, and a little more ferociter.
This article appears in the July 2019 print issue as “The Heavy Lift.”
Post Syndicated from Jeff Foust original https://spectrum.ieee.org/aerospace/space-flight/nasas-lunar-space-station-is-a-greatterrible-idea
NASA’s orbiting Lunar Gateway is either essential for a moon landing or a boondoggle in the making
When astronauts first landed on the moon a half century ago, they went there in a single shot: A Saturn V rocket launched the Apollo command and service module and the lunar lander, which entered into a low orbit around the moon. The lander then detached and descended to the surface. After 22 hours in the moondust, the Apollo 11 astronauts climbed into the lander’s ascent stage and returned to the command module for the trip back to Earth.
NASA’s current plan for sending astronauts back to the moon, which may happen as soon as 2024, goes a little differently. A series of commercial rockets will first launch the components of a small space station, which will self-assemble in high lunar orbit. Then another rocket will send up an unoccupied lunar lander. Finally, a giant Space Launch System (SLS) rocket will launch an Orion spacecraft (which looks a lot like an Apollo command module), with astronauts inside. Orion will dock with the space station, and some of the astronauts will transfer to the waiting lander. Finally, the astronauts will descend to the lunar surface. After their sortie on the moon, they’ll return to the orbital station, where the crew will board Orion for the trip home.
That lunar orbital space station is envisioned as a collection of modules, including habitats, an air lock, and a power and propulsion unit. NASA calls it the Gateway.
Its origins predate NASA’s current plan to return to the moon, which the agency recently rebranded as the Artemis program, and the proposed facility has grown and shrunk in response to changing policies and budgets. NASA argues that the Gateway is an essential part of its human space exploration plans. But others wonder if it’s necessary at all.
The Gateway’s origins can be traced back to President Barack Obama’s cancellation of NASA’s last plan to return humans to the moon (the Constellation program). In an April 2010 speech announcing a new direction for NASA’s human spaceflight efforts, Obama called on the agency to develop vehicles for deep space missions, starting with a trip to a near-Earth asteroid in 2025. However, NASA quickly determined that this goal was too ambitious, as it would require a crewed mission lasting many months. So the agency suggested an alternative: Instead of sending astronauts to an asteroid, they would bring an asteroid to the astronauts.
That idea led to the Asteroid Redirect Mission (ARM), announced in 2013. A robotic spacecraft would grab a small near-Earth asteroid—no more than 10 meters wide—and gradually shift it into a high, stable orbit around the moon, called a distant retrograde orbit, where it could be visited by astronauts on short-duration missions. But doubts about ARM’s feasibility and utility doomed the program when it came up for budget approval in the U.S. Congress.
In 2017, under the new administration of President Donald Trump, NASA pivoted again. The agency had long maintained that the space program would benefit from having a presence in cislunar space—the area between the Earth and the moon—to test technologies for future missions to Mars and beyond. NASA’s next proposal, revealed in March 2017, was a concept called the Deep Space Gateway: a collection of modules in a distant retrograde orbit around the moon. By the late 2020s, astronauts at this built-out Gateway could begin assembling a separate spacecraft, the Deep Space Transport, for long-duration missions to Mars.
That plan also fell by the wayside, though, after President Trump declared a new priority for NASA: sending astronauts back to the moon’s surface, and beginning to build a permanent presence in space.
“This time, we will not only plant our flag and leave our footprints,” President Trump said in December 2017. He had just signed a space policy directive that refocused the U.S. space program on human exploration, and most immediately on returning American astronauts to the moon. The “long-term exploration and use” of the moon, he said, was a step toward even grander projects. “We will establish a foundation for an eventual mission to Mars, and perhaps someday, to many worlds beyond.”
The directive called on NASA to return humans to the surface of the moon using commercial and international partnerships—but left it up to the agency to figure out the best way to do so. NASA’s approach was to repurpose the Gateway, formally renaming it the Lunar Orbital Platform–Gateway and presenting it as a staging area for lunar missions. The Gateway would be assembled in a different orbit, a highly elliptical one over the poles of the moon called a near-rectilinear halo orbit. Spacecraft from Earth can reach this orbit using minimal fuel, so supplies could be shipped up relatively easily and cheaply. With this setup, NASA said, astronauts would return to the lunar surface in 2028.
NASA also worked to bring in international partners, many of which were already involved with the International Space Station. By early 2019, the Gateway was taking form in a much grander configuration than ever before. The proposed configuration featured a power and propulsion element, which would use a solar-electric system to power the Gateway and move it around cislunar space, as well as two habitation modules, utilization and multipurpose modules, and a robotic arm. Canada promised to build the robotic arm; in February 2019 Canadian prime minister Justin Trudeau announced that the country would spend CAN $2 billion on the project. In the Gateway concept drawings, other modules were optimistically emblazoned with the logos from the European Space Agency (ESA), the Japanese Aerospace Exploration Agency (JAXA), and Roscosmos, the Russian space agency.
“This is an aspirational vision of the Gateway,” said NASA administrator Jim Bridenstine in a speech in mid-March. He was discussing NASA’s fiscal year 2020 budget proposal, which included US $821 million for Gateway development. But, he added, he had talked with the leaders of other space agencies, and “they are very excited about partnering with us on going to the moon.”
Two weeks later, the aspirational vision changed dramatically once again. In a speech at a meeting of the National Space Council on 26 March, Vice President Mike Pence ordered NASA to accelerate its plans for lunar return. “At the direction of the president of the United States, it is the stated policy of this administration and the United States of America to return American astronauts to the moon within the next five years,” Pence announced in the speech. The ambitious goal—a moon landing in 2024—took the world by surprise.
It also sent NASA scrambling to figure out how to reach that goal. In an April speech at the Space Symposium in Colorado Springs, Bridenstine said NASA would adjust its plans for lunar exploration, and would focus on only the basic elements required to get humans to the surface in five years. “The first phase is speed. We want to get those boots on the moon as soon as possible,” he said. “Anything that is a distraction from making that happen we’re getting rid of.” And much of the Gateway seemed to qualify as a distraction. Bridenstine suggested that the only parts of the Gateway needed for a lunar landing would be the propulsion module and a habitation node where the Orion spacecraft and lunar landers could dock.
NASA’s international partners were also shocked. The space agencies that had been considering building Gateway components suddenly didn’t know when, or even if, their potential contributions would be needed. Bridenstine acknowledged this confusion in his April speech. “It has been a concern to our international partners, and they have expressed that to me throughout this conference,” he said. But, he argued, these partners could still play roles in the second phase of NASA’s lunar exploration plans—after that initial 2024 landing. Then, he said, NASA will prioritize long-term sustainability in cislunar space, which will include building out the Gateway to something like the configuration discussed earlier.
In the weeks that followed, NASA increasingly talked about building a “minimal” Gateway to support a 2024 lunar landing. In May, NASA announced that the White House would seek an additional $1.6 billion in funding [PDF] in 2020 as a “down payment” toward meeting that deadline. The additional money is primarily intended to support commercial companies in their speedy development of lunar landers and to boost the lagging SLS rocket and Orion spacecraft programs, both of which are years behind schedule and billions of dollars over budget. The proposal also cut $321 million from the budget for the Gateway.
This revised budget “refocuses Gateway a little bit,” said NASA’s associate administrator for human exploration and operations, William Gerstenmaier, in a hastily arranged call with reporters. “Gateway was focused towards a little bit of a larger capability, more than we need just for the landing. This focused Gateway back to just the initial components that are needed to land on the moon.” At the end of May, Bridenstine announced that NASA had selected the Colorado-based company Maxar Technologies to build the Gateway’s power and propulsion element.
Critics of the Gateway argue that NASA shouldn’t just scale back the space station—it should cancel the project altogether. If you want to go to the surface of the moon, the refrain goes, go there directly, as the Apollo missions did a half century ago. Building an outpost in lunar orbit adds expense, delay, and complications to a task that is already hard enough.
Among those critics is former NASA administrator Michael Griffin. Last November, during a meeting with an advisory group of the National Space Council, he offered a devastating critique of the space station. “The architecture that has been put in play, putting a Gateway before boots on the moon, is, from a space systems engineer’s standpoint, a stupid architecture,” he said. NASA should instead go directly to the lunar surface, he argued, and only then set up something like the Gateway to support such missions, particularly once astronauts are able to tap into resources like water ice at the lunar poles. “Gateway is useful when, but not before, they’re manufacturing [rocket] propellant on the moon and shipping it up to a depot in lunar orbit.”
Another prominent critic is Robert Zubrin, founder and president of the Mars Society. He likens the Gateway to a tollbooth, arguing that it adds expense to any future missions to the moon or Mars. He has proposed an alternative plan called Moon Direct that would make use of existing commercial launch vehicles to gradually build up a base on the lunar surface.
Aware of such criticisms, NASA is defending the Gateway. In May, the agency quietly distributed a white paper titled “Why Gateway?” [PDF] that makes the case for the space station. “NASA’s position, based on technical and programmatic analysis, is that the Gateway enables the most rapid landing of the next Americans on the moon,” it stated. Among the reasons it cited: Orion’s main engine is too weak to propel the spacecraft into a low orbit around the moon, requiring a staging area like the Gateway in its higher orbit.
“On balance, the near- and long-term benefits of pressing forward with the Gateway architecture far outweigh the risks of incurring substantial delays and inefficiencies that would inevitably result from a change to the architecture at this late date,” the white paper concluded. Such changes, like increasing the performance of the Orion’s propulsion system to enable it to reach low lunar orbit, might add billions to the roughly $30 billion spent to date on SLS and Orion and do nothing to achieve the 2024 deadline.
That reliance on SLS and Orion worries some moon enthusiasts, as both technologies are still under development—and both projects have encountered significant cost overruns and delays. Last October, NASA’s inspector general issued a scathing report [PDF] of the SLS program, which at that time was three years behind schedule and billions of dollars over budget. Yet NASA and its allies say there’s no other way to the moon.
“The elements that we have right now can’t do that [lunar landing] mission without Gateway,” said Mike Fuller, who handles business development for NASA programs at Northrop Grumman. He believes Orion’s limited propulsion is actually a design strength. The Apollo missions sent the control modules into an orbit about 100 kilometers above the moon, but “it was disadvantageous to go that deep” into the moon’s gravity well, he says. Having Orion come to rest at a higher orbit makes it easier to abort back to Earth, as less propulsion is required.
Would it be possible for NASA to abandon the Gateway and its mission architecture entirely? Critics say that technological alternatives are emerging in the commercial space sector. They look to Blue Origin, the space company founded by Amazon billionaire Jeff Bezos and based near Seattle. Blue Origin is building both a reusable heavy-lift rocket, called New Glenn, and a lunar lander known as Blue Moon. Another contender is Elon Musk’s SpaceX, based in Hawthorne, Calif., which is also working on a fully reusable rocket. It will carry an upper stage called Starship, which the company says could land directly on the moon and carry heavy cargo. “Having that vehicle on the moon can basically serve as the core of a pretty significant lunar outpost, growing with time,” said Paul Wooster, principal Mars development engineer at SpaceX.
However, the exciting spacecraft from these companies are still under development, and it may be years before they’re ready for lunar-landing missions. Moreover, any attempt to cancel SLS or Orion would likely face stiff opposition in Congress, particularly by influential members in states where work on those vehicles takes place. Perhaps it’s no surprise, then, that NASA is doubling down on its Gateway plan. In May, while discussing NASA’s revised budget proposal, Bridenstine said the Gateway is vital to achieving a 2024 lunar landing. “The Gateway is as important now as it was before,” he said. “We cannot overemphasize how important the Gateway is.”
If NASA, heedful of sunk costs and political realities, continues to march toward the Gateway, we may indeed witness a triumphant return of NASA astronauts to the moon’s surface in 2024. NASA has defied the odds and met grand challenges before. But it’s also possible that the plan won’t survive budgetary debates in Congress, or that the 2020 elections will bring a new administration that will change the course of the lunar exploration program yet again. In which case, the determined billionaires behind SpaceX and Blue Origin might not wait around for NASA, and the next moon boots in the regolith might stamp a corporate logo in the dust.
This article appears in the July 2019 print issue as “Gateway or Bust.”
Post Syndicated from IEEE Spectrum Recent Content full text original https://spectrum.ieee.org/static/project-moon-base
Humans are preparing to build the first permanent settlement in space
Humans are preparing to build the first permanent settlement in space
1. Getting There
Technology, billionaires, and geopolitics will all help get us back to the moon, but they won’t be enough to let us live there indefinitely
Space agencies and private companies are working on rockets, landers, and other tech for lunar settlement
In a cavernous building in Washington state, Blue Origin workers are building New Glenn’s BE-4 engine
NASA’s orbiting Lunar Gateway is either essential for a moon landing or a boondoggle in the making
2. Building It
NASA and the European Space Agency’s plans for moon colonies call for advanced life-support systems and shielding from cosmic rays
Here’s how lunar explorers will mine the regolith to make rocket fuel
Astrobotic’s autonomous navigation will help lunar landers, rovers, and drones find their way
To write his new novel, Red Moon, Robinson became expert on the technologies that will enable a lunar colony
3. Living There
Apollo astronauts inhabited the moon for just a few days—but the long-term physiological effects could be severe
NASA’s Orion and Lunar Gateway will try out optical communication gear for a high-speed connection to Earth
Astronomers need a quiet place to observe the cosmic dawn
If you can’t visit our celestial neighbor yourself, Ian McDonald has some recommendations to give you a taste
IEEE Members share first-hand stories from the Mercury, Gemini, and Apollo programs
A 1946 demonstration called Project Diana marked the beginning of space communications
The real-life Hidden Figures mathematician calculated trajectories for Mercury and Apollo astronauts
Starting in the 1950s, space agencies used kid-friendly mascots to make the case for space
Post Syndicated from Sally Adee original https://spectrum.ieee.org/aerospace/space-flight/kim-stanley-robinson-built-a-moon-base-in-his-mind
To write his new novel, Red Moon, the sci-fi author became an expert on lunar colony tech
Like many of the best science fiction writers, Kim Stanley Robinson builds future worlds so grounded in technological and scientific fact that engineers sometimes turn to his work for reference material when they begin to build the real thing. His research process is legendary; before he starts writing, he can spend years going to obscure conferences, talking to scientists and reading their papers. The official flag of the Mars Society, with its bands of red, green, and blue, was designed by NASA geophysicist Pascal Lee as an homage to Robinson’s books.
Yet Robinson is humble about his influence. After his canonical trilogy about the settlement of Mars attracted attention from policy wonks in D.C. and planetary scientists at the Jet Propulsion Lab alike, he described their interactions as simply chats about a “subject of mutual interest.”
Robinson’s latest book imagines our future on the moon. It’s exacting in its detail and has already shown to be prescient: Since Red Moon was published in October 2018, the Chinese have announced a plan to build a base at the lunar south pole, right where Robinson placed their outpost in his book. He talked to IEEE Spectrum about the world he conjured in his work and what it might tell us about our lunar future, why you can’t colonize the moon for profit, what kind of tech will be necessary to get and stay there, and why the best spoils will go to China.
IEEE Spectrum: You invented a completely new technology for landing on the moon. It seems to combine a maglev train, a railgun, and a hyperloop. Can you briefly describe how that works and how you came up with it?
Kim Stanley Robinson: I got the idea from a lunatic friend of mine. It’s basically the reverse of the magnetic launch rails that have been postulated for getting off the moon ever since the 1930s: These take advantage of the moon’s light gravity and its lack of atmosphere, which allow a spaceship to be accelerated to a very high speed while still on the surface, after which the ship could just zoom off the moon going sideways, because there is no atmosphere to burn up in on the way out. If you just reverse that process, apparently you can land a spaceship on the moon according to the same principle.
It blew my mind. I asked about the tolerance for error; how precise would you have to be for the system to work? My friend shrugged and said it would be a few centimeters. This while going about 8,000 miles an hour (12,900 kilometers per hour)! But without an atmosphere, a landing can be very precise; there won’t be any winds or turbulence, no friction. It was so fantastic a notion that I knew I had to use it.
Spectrum: What other research did you undertake to write Red Moon?
Robinson: I was able to use a lot of what I had learned from my Mars books, which was good, because while I also read the current scientific literature on how we could set up a base on the moon, that’s not a huge body of work. Compared to something like biotechnology, the moon is kind of a miniature field of study. But I got a lot from the experts who are working up the plans to get back to the moon now.
Spectrum: What did they tell you about what crewed moon bases will look like?
Robinson: As with Mars, but maybe even more so, my model for these moon bases is Antarctica. I’ve visited McMurdo and South Pole Station, and I think how those places operate are a good proxy for how it will be on the moon. We’ll build these bases stage by stage, then staff them with rotating crews of scientists and people who will keep the place going. No one will live there permanently. That will be the safest plan for keeping people healthy, because of the moon’s gravity, which is one-sixth that on Earth.
Spectrum: This book is set in 2047. Do you really think the sophisticated colony you envision can be built by then?
Robinson: I do think it’s possible to build these bases in 28 years. Really, what I describe in the book is not all that extensive. Ordinary speeds of construction would suffice to get a significant amount done over three decades. Obviously we would have to get there first, but that’s not the hardest thing to do anymore. Only a three-day trip. None of this is rocket science, except, of course, for the rocket science.
Spectrum: Are the poles the only places on the moon that can be colonized?
Robinson: Most of the moon has long lunar nights. The poles have near-permanent light for solar power and water already there to use, and are clearly the best places to occupy. But the other place I think people will be interested in is the libration zones, running up both sides of the planet. Galileo was the first to notice these, with his first telescopes: They are the only places where the Earth will rise and set over the horizon. People will enjoy seeing Earthrise and Earthset, so I portrayed my Chinese characters building up the libration zones, starting from the south pole.
Spectrum: The lunar south pole has places that experience 100 percent sunlight, which is why it has been chosen by China—the first nation to build settlements. Is the speed of the colonization process tied to your prognosis that China will dominate the moon rush?
Robinson: I see the Chinese now building infrastructure on Earth very quickly, by way of their Party and their state-owned enterprises as primary drivers and organizers and funders, and the Chinese population as the workforce. Their new seaports, high-speed rail, entire new cities, all these illustrate their ability to build infrastructure fast. They’re already building more infrastructure than they need just to keep their economy humming. The moon could function as more of that, plus add to national prestige. They have the workforce and a tremendous capital surplus. They also have the advantage that they are not solely driven by profits.
Spectrum: Could a Western society do it?
Robinson: Maybe, but not for profit. And capitalism is for profit. The problem in the West, in our version of capitalism, is that if you say the investment will pay off for the next generations, the investors will say, “Thanks, but I need quarterly profits at the highest rate of return,” and go back to immiserating labor and strip-mining the biosphere in their usual way. We have allowed the market to rule us like an emperor.
China’s “socialism with Chinese characteristics” seems to mean a state-controlled economy that directs the private sector and can pay the private sector. They might be quicker to take on this obviously not-for-profit venture. China is better equipped mentally and structurally to do it.
Spectrum: Some people think there is profit to be found on the moon. There has long been talk of Helium-3 as an economic motive: Mine it there and use it to fuel nuclear fusion reactors back on Earth. But you’ve made H-3 into something of a joke in the book. Why?
Robinson: It’s too diffuse in the lunar surface materials. Sure, it’s there, but at around 15 parts per billion, so you’d have to plow up immense amounts of the lunar surface and have a good extraction method too, all to collect fuel for a kind of power plant we don’t have yet! No. What Helium-3 is, in the discussions today, is a desperate reach for something that might make an economic rationale for going to the moon. But there is no such rationale. The moon has nothing people can make money from. As we live in a capitalist economy, that’s hard for some people to admit.
Spectrum: So why go at all?
Robinson: Each country will have its own reasons, which I go into in the book. Generally, though, I think it reduces to about three good reasons: for science, for a nice view of Earth, for an eventual good launching pad to elsewhere in the solar system. And as with the moon, China is in the best place to start exploring the solar system, because they aren’t as completely driven by profits.
Spectrum: Your books tend to be one book masquerading as another book. The Mars trilogy is ostensibly a book about terraforming Mars, but it actually turns out to be a manifesto for turning a utopian political philosophy into reality (or not). So here we have a book that is ostensibly about colonizing the moon. What is this one really about?
Robinson: Yes, my books definitely do what you’re talking about. But for Red Moon, which is set so close to the current moment, the underlying “really” is the same thing as the explicit plot—it’s about China taking over the moon. China and the United States are the two crucial players in world history in our time, and neither country has a really effective system of political representation, and both exist in an important way under the rule of global capital, a rule that is wrecking the biosphere and people’s lives.
Can ordinary citizens in these two countries team up to take the world back from capital and return it to real political representation? We’ll need to do that to stabilize human civilization in Earth’s biosphere. We’ll need to change the way we value things. Once we figure that out, then we’ll be poised to go further into the solar system. Not as an escape hatch—that’s a pernicious fantasy. The solar system deserves to be studied and explored apart from its market value, just as a subject of comparative planetology, to learn things we need to know. Space science is crucial for the survival of civilization.
Post Syndicated from Matthew Hutson original https://spectrum.ieee.org/aerospace/space-flight/engineers-and-architects-are-already-designing-lunar-habitats
NASA and the European Space Agency’s plans for moon colonies call for advanced life-support systems and shielding from cosmic rays
Skidmore, Owings & Merrill is the architectural firm known for designing and engineering Dubai’s Burj Khalifa, the world’s tallest building, such iconic structures being one of the firm’s specialties. But at its New York City office, architects are working on something even more striking—drawings for SOM’s first extraterrestrial assignment. The firm is designing a moon base in collaboration with the European Space Agency (ESA) and MIT.
Daniel Inocente, the lead designer, presents schematics and renderings of white puffy pods scattered across the lunar landscape, connected by tubular walkways and surrounded by robots and solar panels and astronauts, all overseen by a recognizable blue orb in the sky.
These visions may never come to be, but they’re helping ESA think through possible futures. The moon offers many opportunities. Planetary scientists want to study its composition to learn about the early solar system and Earth’s origins. Astronomers want to build radio telescopes on the far side. Medical researchers want to understand how the human body reacts to extended stays in low gravity. Explorers want to test equipment or produce propellant for voyages to asteroids, Mars, and beyond.
Talk of sending people back to the moon—for the first time since the Apollo missions ended in the 1970s—has heated up recently. In 2016, the head of ESA announced Moon Village, a deliberately nebulous vision encouraging private and public players to collaborate on robotic and human exploration of the moon. Last year, eight Chinese volunteers completed a yearlong stay in a simulated habitat called Lunar Palace 1 to test life-support systems.
And while private industry doesn’t plan to send people to the moon’s surface anytime soon, rockets from SpaceX and Blue Origin could drastically reduce the cost for governments to do so. Just a few months ago, U.S. vice president Mike Pence pledged to return astronauts to the moon within five years.
But settling people on the moon will require experts to work out some kinks, to put it lightly. These include coping with the harsh environment, building structures out of locally sourced materials, mastering life support, and dealing with one potentially deadly complication for which we currently have no clear solution: dust.
The three most important factors in identifying a site for a lunar settlement are, as any realtor will tell you, location, location, location. Skidmore, Owings & Merrill (SOM) has deemed the most enticing option to be a nice bit of property on the rim of the Shackleton Crater near the moon’s south pole.
There’s strong evidence that permanently shadowed regions of the crater contain water ice from ancient comets—good for drinking, cooking food, bathing, making concrete, and splitting into oxygen and hydrogen for rocket propellant.
Wherever they build, space architects and engineers face constraints that traditional practitioners never worry about. The moon has almost no air, of course, so any habitat must be sealed and pressure-tight. And while most space rocks burn up in Earth’s atmosphere, the moon’s surface is constantly pelted with micrometeoroids. So structures would have to be built to take that punishment.
Gravity is about one-sixth as strong there as on Earth. That can allow for long-span structures, but it also requires more anchor points. And weak gravity makes it hard to dig: Pushing down pushes you up. Where temperatures are extreme, habitats will need to incorporate powerful heating and cooling systems, and the materials they are made of will have to withstand dramatic amounts of expansion and contraction.
Then there’s the radiation. The sun emits a constant stream of high-speed protons and electrons—the solar wind. While Earth’s magnetic field shields us from most of this wind, the moon has no magnetic field, so it all hits the surface. Even more dangerous are the sun’s coronal mass ejections. These events hurl bursts of higher-energy protons and electrons into space. A strong one could generate several sieverts—a sievert being a measure of radiation exposure—on the moon’s surface, enough to kill a person if she or he doesn’t return to Earth for a bone marrow transplant. And if such dangers weren’t enough to endure, astronauts on the moon will also be subject to a constant shower of galactic cosmic rays, which will probably increase their lifetime risk of cancer.
At SOM’s New York City office, Inocente describes his firm’s proposal to 3D-print walls around the pods of a lunar habitat to guard against deadly radiation. Long-term occupants will need up to 3 meters of shielding to protect themselves from galactic cosmic rays. It wouldn’t make sense to ship tons of concrete from Earth, so astronauts will apply what’s known as in situ resource utilization—in other words, they’ll use what’s there.
In SOM’s conception, the walls will be made from lunar soil—which, lacking organic material, is more properly called regolith. One way to do this is to 3D-print the walls, either all in one piece where they’ll stand, or as bricks that lock together when stacked. Some space architects propose depositing regolith-based cement, layer by layer, through a robotically controlled nozzle.
But what if the liquid used in the cement mixture evaporates or freezes before the concrete in the wall or brick sets? European researchers working with the architecture firm Foster + Partners have explored binding liquids and injection methods that would prevent this, and they have printed a section of a wall using a regolith simulant. However, contractors would still need to ship the liquid binder or special cement powder to the moon.
SOM prefers extruding melted regolith through a nozzle like hot glue. Yet another approach is sintering—heating regolith to near its melting point until it fuses. In one ESA project, called RegoLight, researchers focused sunlight into an intense beam and traced it over the surface of regolith simulant, baking bricks layer by layer. The process was slow, though, and the test bricks were weak, so many researchers believe the winning strategy will be microwave sintering, which uses microwave ovens or beams to bind dust. SOM is closely following the sintering research.
For relatively low habitats, regolith may simply be piled on top of metal structures (with space left open for maintenance). Another, more speculative option, is to place habitat modules inside the moon’s lava tubes—large empty tunnels through which molten rock once flowed.
Regolith will be used not only to protect buildings but also to pave launchpads and roads. Brent Sherwood, chair of the Space Architecture Technical Committee of the American Institute of Aeronautics and Astronautics (AIAA), suggests baking regolith paving tiles in microwave ovens. Spacecraft landing on platforms or vehicles driving on roads made of these tiles would kick up less dust. The roads would also make it easier for robots to navigate the terrain. “You basically want to make the surface of the moon into a predictable factory floor, like an Amazon warehouse,” he says.
Hanna Läkk, a space architect at ESA with a background in architecture and textile technology, has offered a more far-out use of regolith. With collaborators, she’s managed to melt simulant and extrude it into fibers that can be robotically wound across metal frameworks into fibrous shell structures. With this fabrication method, a habitat module could be placed in a crater with woven webs spanning it, supporting more regolith piled on top. They have also used a robot to fabricate a miniature version of such a cover. In the end, many techniques for using regolith will likely be adopted in any future moon colony.
Behind barriers made of moon regolith, what will lunar habitat modules actually look like? SOM’s in-progress designs are an outgrowth of proposals made by engineers over the decades, usually for domes or cylinders, sometimes buried or half-buried.
Space architects and engineers widely believe that the first moon habitats will resemble units of the International Space Station (ISS). “The first-generation technology is a little bit less sexy” than sci-fi renderings, says Haym Benaroya, a mechanical and aerospace engineer at Rutgers University and the author of Building Habitats on the Moon: Engineering Approaches to Lunar Settlements (Springer, 2018). The original habitat will be some sort of pressure vessel covered in regolith for radiation protection—in a sense, a buried tin can.
According to Sherwood, who worked on ISS modules for Boeing, engineers already know how to fabricate, test, launch, and repair such a unit. “The amount of learning that we’ve gotten out of the space station is enormous,” he says.
Eventually, we might switch to inflatable modules—which could expand to greater volumes, once we better understand how to integrate them with rigid structures and how to pack them so they unfold properly. Bigelow Aerospace, a company based in Las Vegas, licensed NASA patents to build an inflatable unit that was attached to the ISS in 2016 for testing. While it’s currently being used only for storage, Bigelow continues to collect data on its response to temperature changes, radiation, and impacts from space debris.
In its work with ESA, SOM has opted for something between a can and a balloon. The module its architects have designed is vaguely cylindrical and stands 9.5 meters tall. It has three floors, with a vertical core that allows inhabitants to climb between them. Three inflatable portions run the height of the module and add living space to all floors. The bottom level has three doors to connect to neighboring units.
Post Syndicated from Ian McDonald original https://spectrum.ieee.org/aerospace/space-flight/5-mustread-books-about-the-moon
If you can’t visit our celestial neighbor yourself, Ian McDonald has some recommendations to give you a taste
Ian McDonald is a Hugo Award–winning novelist who has written books about Martian colonization, nanotechnology, and artificial intelligence. His latest series of Luna books are set in a near future where the moon is ruled by five families on a neofeudal basis. IEEE Spectrum invited him to share a selection of moon-related books that have moved and inspired him.
I remember the moon landing. I remember brilliant sunshine and being called in to see Neil Armstrong set foot on the surface. My family sat around the black-and-white television, the curtains drawn as if for a funeral. Light blazed though the gap between the curtains. I remember Neil Armstrong stepping down from the lunar module. I was 9. I grew up a space kid, thrilled by rockets, astronauts, cosmonauts, the Great Out There.
The memory is strong, vivid—and entirely wrong. When the Eagle landed it was 8:17 p.m. in Belfast, Northern Ireland, where I lived. Armstrong didn’t set foot on the surface until nearly 3:00 a.m.
The Moon Is a Harsh Mistress
I have to talk about this classic novel. Written by Robert A. Heinlein and published in 1966, three years before the moon landing, it feels like a sibling of the Apollo project. It stands like a monolith over every moon story since. There had been moon bases in fiction before, but they were anemic, sterile: bubbles of white Westerners engaged in research. The Moon Is a Harsh Mistress gave us a whole world that was noisy, crowded, smelly, colorful, diverse, and chaotic. It was alive.
The setup—the moon as a penal colony à la Botany Bay—doesn’t stand much examination, and the economics of feeding Earth with moon-grown grain makes no sense. The politics are interesting only to a 14-year-old and riddled with American exceptionalism, the women characters are barely there, and the professor character—the inevitable Heinlein pontificating windbag—should be thrown out the airlock in chapter three. Yet I love it. Revolution and a new society is inevitable in his moon base, but that isn’t what I come to this book for. I come for the life, the energy. I can imagine looking up on a clear night and seeing the lights up there, in the dark of Heinlein’s moon.
The Moon and the Other
In my opinion, reasons to go to the moon are few, reasons to stay fewer. Yet John Kessel’s novel, The Moon and the Other, gives one of the cleverest rationales for settling the moon: It’s a giant social science laboratory. In the year 2149, 3 million humans live on the moon in 27 distinct cultures. One culture is the Society of Cousins, where men trade political rights for social status so as to limit the potential for male violence. That society rubs up against the more traditionally patriarchal Persepolis, which has evolved from an Iranian experiment in secularism.
Four characters experience relationships, love, and other disasters in a rich social comedy. The book is witty, charming, and light-footed, hitting its targets with elegant precision (think of it as a fencer’s foil, while Heinlein’s novel is a brass cannon). Kessel takes a smart look at the fallibility of human institutions, but also argues that there’s hope in our imperfections.
Moondust: In Search of the Men Who Fell to Earth
The premise of this nonfiction narrative is irresistible. In 2004 Andrew Smith learned that only nine of the 12 men who had walked on the moon were still alive, so he set out to meet them before Apollo vanished over the temporal horizon. What he describes in Moondust: In Search of the Men Who Fell to Earth is extraordinary: He found alcoholics, depressives, New Age gurus, devout evangelicals, visual artists, and grumpy old men. All shared the same experience of looking up and seeing a tiny Earth that Neil Armstrong could block out with the tip of his thumb. The Earth light changed them; none were untouched, all struggled to express it. The experience seemed beyond human communication.
Amazing details abound in Smith’s book: The moonwalkers were paid US $8 a day, minus deductions for berths on Apollo. These men were fired into space on a stick of high explosive, lauded as heroes, paid a pittance, and then effectively abandoned by NASA. They had a fall to Earth indeed. This is a melancholic book, shot through with a sense that we failed the moonwalkers and the vision of humans exploring space. It’s now 50 years since Apollo 11, and of the moonwalkers, only four remain.
The Astronaut Wives Club
The moonwalkers flew, but what of those they left behind, earthbound?
Lily Koppel’s nonfiction book The Astronaut Wives Club answers that question. There was wonder, yes; but also stress, anxiety, fear. Devised as a support group for the families of the Mercury, Gemini, and Apollo astronauts, the club gathered together the women who fell into lives every bit as rehearsed and controlled as their husbands’. Every aspect of their family life, even their clothes, were micromanaged to generate the right impression. Just like their husbands, these women had to show the public that they had “the right stuff.” But behind the gleaming homes and swimming pools lay addiction, mental illness, alcoholism, abandonment issues, and, in the case of Annie Glenn, a passion for fast cars.
Tragically, 7 of the 30 members of the Astronaut Wives Club lost their husbands in the space program—3 in the Apollo 1 fire. The public facade began to crack, and in the aftermath of the human space flight program, when the men returned to Earth, it collapsed completely. Adultery, divorce, suicide: This book is strongest when it illustrates how wrong the right stuff can be.
Visiting NASA is a short graphic novel by Alison Wilgus, but it packs a deep snort of awe and delight. It’s a chronicle of the author’s visit to NASA’s Kennedy Space Center recorded with a clear, strong line and deep personal engagement. We share her respect for the work and dedication of the NASA staff and her amazement at the scale and vision of the space program. Wonder bubbles out of this small book like spring water, and wonder is the very fuel of science fiction. While not a book about the moon per se, it’s absolutely of the moon, Apollo, and the Great Out There. By the time you come to the final page, where the author watches a launch, it’s hard not to cheer. It’s the same wide-eyed joy I felt as a 9-year-old during that rocket summer when humans landed on the moon.
Post Syndicated from Jeff Hecht original https://spectrum.ieee.org/tech-talk/aerospace/satellites/backup-laser-to-revive-aeolus-satellite
Early results have shown that ultraviolet lidar can provide vital new data for weather and climate studies, but the laser power is slowly fading
Firing laser pulses from a satellite is the best way to measure wind velocity. Thus the launch of the lidar-equipped Aeolus satellite last August marked a breakthrough in measuring wind speeds around the world from the ground to the stratosphere for use in weather forecasting and climate research.
Its first nine months proved its worth. “The quality of the wind data is fantastic,” Josef Aschbacher, director of Earth observations at the European Space Agency, said in May. However, the high energy pulses from the Aladin ultraviolet laser used to make the measurements were growing dimmer.
This week ESA is switching on a backup laser, and expects to spend three to four weeks commissioning it. “The first data, available only to expert users, should be available around the end of July,” Aeolus mission manager Tommaso Parrinello told Spectrum in an email. ESA expects to need another month to confirm data quality for continuing studies of weather and climate.
Weather and climate trends depend on wind velocities, so accurate measurements of their throughout the atmosphere are essential for weather forecasting and climate research. We can estimate wind velocity indirectly by watching the motion of wind-driven clouds and the turbulence of wind-blown ocean surfaces. However, the most accurate velocity measurements come from inserting probes directly into the moving air. Weather balloons are the most common probes, supplemented by ground-based and aircraft-mounted instruments, but the numbers of these probes are limited.
Firing laser pulses into the air is another way of measuring wind velocity. Putting the laser on a satellite allows its pulses to probe the atmosphere around the whole world. Air molecules scatter some laser light directly back at the laser, in the process shifting the wavelength slightly by an amount that depends on the velocity of the molecule. A sensor mounted on the satellite can detect the difference between the laser output and the reflected light, thus measuring the air speed. This kind of laser is called a laser radar or lidar, and it is best known for its short-range uses in police speed traps and self-driving cars.
Lidars have been flown in space before, but mostly for measuring distance to the ground. One famous example is the Mars Orbiter Laser Altimeter which mapped the red planet from the Mars Global Surveyor. That worked well because hard surfaces reflect much of the laser energy. Air, on the other hand, reflects only small fraction of the laser light, making it harder to measure wind velocity. However, air scatters more light at shorter wavelengths, so lidar returns can be increased by using lasers firing high energy pulses at short ultraviolet wavelengths.
ESA custom-built a high-power laser they called Aladin to operate very stably, firing 50 pulses per second in a precise band for measurement. The laser worked well, but when they tested the optical system in a vacuum in 2005 they found that the intense ultraviolet pulses destroyed fragile coatings on optical surfaces and clouded the optics. Fixing that took more than a decade and raised the total cost of Aeolus to $560 million when it launched last year.
The laser fired ultraviolet of 65 millijoules once it reached orbit, but that energy declined 20 to 30 percent in the first nine months, and Aschbacher said it was losing one millijoule per week in May. That was a big advance over earlier high-energy ultraviolet lasers in space, which failed within a few hours, Parrinello says. The European Center for Medium-Range Weather Forecasts found the resulting data was good enough to improve weather-forecast quality. However, at the rate power was dropping, Aeolus would not be able to collect the three years of data sought for research.
Analysis of satellite performance found the losses originated from multiple problems with the laser rather than a recurrence of the earlier optical difficulties. The laser beam seems to be drifting away from the target area, reducing power delivered. The semiconductor diode lasers that convert input electricity into the light that powers the ultraviolet laser appear to be dimming.
Fortunately, ESA’s design included a redundant laser designed as a backup to the original. The backup laser’s design is essentially the same as that of the fading laser, but the backup was not being used, and ground tests show that its pulse energy can be adjusted more readily. That extra margin of the backup laser should be good enough for Aeolus to collect the desired three years of data, Parrinello says, but warns that high-power laser missions, “are only one shot away from failure.” Satellite lifetime also is limited by the limited fuel available to stabilize its orbit at 320 kilometers, an elevation so low it requires a boost every week.
Results from Aeolus have already raised interest in a follow-up operational satellite for meteorological observations, and Parrinello says ESA has already exchanged letters of interest with the European Organization for the Exploitation of Meteorological Satellites.
Apollo astronauts inhabited the moon for just a few days, but the long-term physiological effects of lunar living could be severe
They were called the “dusty dozen” for good reason. The 12 Apollo astronauts who walked on the lunar surface between 1969 and 1972 kicked up so much moondust that the powdery sediment got lodged in every nook and cranny of their space suits. Caked in the stuff, the astronauts inadvertently tracked the toxic dust into their spacecraft and even back down to Earth upon landing.
These NASA astronauts complained of a “lunar hay fever” that irritated their eyes, lungs, and nostrils. A doctor who helped the Apollo 11 crew members emerge from their dust-scattered space module following its ocean splashdown experienced allergic reactions of his own. “Dust is probably one of our greatest inhibitors to a nominal operation on the moon,” Apollo 17 astronaut Gene Cernan, the last man to walk on the moon, said during a postflight debriefing. “I think we can overcome other physiological or physical or mechanical problems, except dust.”
Billowing clouds of dust particles—jagged and abrasive for want of weathering and atmospheric reactions—are hardly the only health hazards posed by a lunar mission, though. Galactic cosmic rays would bombard lunar inhabitants with a steady stream of high-energy radiation. The level of gravity on the moon—about 17 percent that of Earth’s—could wreak havoc on bones, muscles, and other organs. And then there are the psychological aspects of what one NASA astronaut described as the “vast loneliness” of the moon.
As humanity prepares to return to the moon and eventually colonize it, scientists are now actively probing these risks and beginning to devise medical countermeasures. Yet solid evidence on the health consequences of lunar living is extremely limited. “Except for the Apollo experience, we really have no data,” says Laurence Young, a space medicine scientist in MIT’s department of aeronautics and astronautics—and those Apollo missions were never designed with biomedical research goals in mind.
In contrast, the International Space Station (ISS) was established as a giant floating laboratory from the get-go, and nearly two decades of experiments from the continuously inhabited station do offer some clues about what it might be like for people to live on the moon for extended durations. But a zero-gravity space station orbiting within the protective halo of the Earth’s magnetic field is hardly analogous to the moon’s surface, with its partial gravity and harsher radiation.
Researchers therefore have to settle for approximations of lunar conditions. They study proxy dust instead of the real thing, because moondust collected by Apollo astronauts remains scarce. (And even those precious Apollo samples became less reactive after coming into contact with the Earth’s moist, oxygen-rich air.) The researchers simulate galactic radiation by using particle accelerators to create the kinds of energetic heavy ions found in deep space. And they have a variety of tricks to fudge one-sixth gravity: They take parabolic flights that induce short bursts of moonlike conditions; use harnesses and other body-weight support systems to mimic the biomechanics expected in reduced gravity environments; and place subjects in tilted beds for weeks on end to model the effects of lunar gravity on heart function.
The imitations are never perfect, but they are informative. Last year, an interdisciplinary team from Stony Brook University, in New York, exposed human lung cells and mouse brain cells to dust samples that resemble the regolith found in the lunar highlands and on the moon’s volcanic plains. Compared with less-reactive particulate materials, the toxic dust caused more genetic mutations and cell death, raising the specter of moondust triggering neurodegeneration and cancer in future lunar explorers. “The DNA is being damaged, so there is a risk of those types of things happening,” says Rachel Caston, a molecular biologist who led the research. (She’s now at Indiana University–Purdue University Indianapolis.)
But will the same damage happen inside the human body? And if so, would ensuring the safety of future moon settlers require the equivalent of a mudroom, an expensive and logistically challenging piece of equipment to haul over to our celestial neighbor? And just how clean would that mudroom have to be to keep astronauts safe?
“We just don’t know, and therein lies the current conundrum,” says Kim Prisk, a pulmonary physiologist at the University of California, San Diego. “Is this just a nuisance dust, or something potentially very toxic?”
None of the Apollo astronauts suffered any long-term ill effects from dust exposure, only acute respiratory problems—which suggests the lunar schmutz might not be too nasty. But the longest stay on the moon so far was the Apollo 17 astronauts’ 75-hour mission, the equivalent of a long weekend getaway. Plus, with only 12 human data points to draw from, many uncertainties remain. To be on the safe side, when it comes to lunar dust, “a mitigation strategy must be in place before we establish habitats on the lunar surface,” says Andrea Hanson, an aerospace engineer at NASA who previously managed the Exercise Physiology & Countermeasures Lab at Johnson Space Center.
But Hanson sees a bigger concern than lunar dust: exposure to cosmic rays, the high-energy particles from beyond our solar system that constantly pummel the moon. She worries in particular about what a large shower of these reactive ions might do to an astronaut’s sensitive organs, such as the brain and heart.
To study that kind of scenario, in 2003 NASA built a Space Radiation Laboratory at the Brookhaven National Laboratory in New York state. It’s the first and only facility in the United States capable of producing heavy ions of the kind found in outer space. There, researchers blast mice with cosmiclike rays to show, for example, how space radiation can seriously harm the gastrointestinal tract or how a potential prophylactic drug treatment could protect the brain from radiation-induced cognitive decline.
Mouse experiments also underpin Mary Bouxsein’s investigations into the effects of partial gravity on musculoskeletal health. Her research will take place aboard the ISS in a spinning cage contraption built by the Japan Aerospace Exploration Agency. This counterbalanced centrifuge will allow Bouxsein, a biomechanical engineer at the Beth Israel Deaconess Medical Center, in Boston, to monitor mice living at a variety of gravity levels for weeks at a time in order to determine whether lunarlike gravity is enough to preserve proper bone and muscle function. “It’s impossible on Earth to do a true artificial gravity experiment,” Bouxsein says, whereas on the ISS “we can actually, truly look at the protective effects of artificial gravity.”
Ben Levine, director of the Institute for Exercise and Environmental Medicine, a joint program of the Texas Health Presbyterian Hospital Dallas and the University of Texas Southwestern Medical Center, predicts that the moon’s one-sixth gravity will not put enough weight on our bodies to protect against loss of bone mass, muscle strength, and heart pumping capacity. But fortunately, he points out, effective exercise regimes already exist that can be adapted for life on the moon. “If you do what they do on the space station now,” Levine says, “you should be able to completely prevent ongoing atrophy.”
The daily cardio and strength training now common for ISS astronauts might be difficult to achieve in future moon explorations, though—their 2.5-hour workouts include weightlifting, running, and biking on machines that use bungee cords to pull at them. That’s why Tobias Weber and his colleagues at the European Space Agency’s European Astronaut Centre in Cologne, Germany, have been studying streamlined alternatives. As part of the Movement in Low Gravity Study, ESA’s Space Medicine Team recently used a specially designed treadmill that allows people to run, walk, and hop while suspended horizontally by a series of cables.
Adjusting the force by which pulleys bring users laterally back toward the treadmill allows the system to provide various levels of gravity. With this “verticalized” treadmill setup, the researchers showed that just a few minutes of daily hopping, in a simple up-and-down movement akin to skipping rope, could exert enough force on the bones, muscles, and tendons in lunar gravity to combat the physiological degradation expected to occur on the moon.
“Jumping may be a really potent multisystem countermeasure,” says aerospace physiologist David Green, a member of the ESA team. As an added bonus, the short bouts of hopping may be more efficient—and less boring—than running on a treadmill, he adds. “At least at the start,” Green says, “it is hard not to smile when you’re hopping.”
Ultimately, it’s likely that lunar missions will proceed just as they did in the Apollo era: with many health questions unanswered and few protective medical procedures fully worked out. That situation may sound frightening to some would-be moon-trotters, but the uncertainties don’t faze Bill Paloski, director of NASA’s Human Research Program.
“I’m actually not terribly concerned about health and physiology issues,” he says. “We’ll be able to monitor closely enough the overall health and performance of crew members and then provide near-real-time support from Earth for most things.” In the worst-case scenario, astronauts could fly home in a matter of days—a rescue plan that won’t be possible as the mission moves on to Mars and beyond.
That’s what makes the moon such an “interesting stepping stone,” Paloski says. “It’s a way of testing a lot of the concepts we have for how to do things on the Mars surface.”
About the Author
Elie Dolgin is a science writer specializing in biomedical research and drug discovery. After a Ph.D. spent studying the population genetics of nematodes, he swapped worms for words—entering journalism as an editor at The Scientist, Nature Medicine, and STAT. Now a freelancer, Dolgin is a frequent contributor to New Scientist, Nature, IEEE Spectrum, and more.
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