How to land a spaceship | Space



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Regardless of the mission that astronauts send to perform, the engineers who send them need to solve two basic problems: how to get space travelers off the Earth (and put them in orbit or on the way to the Moon or Mars) and how to bring them come back again. With decades of experience in pushing charges into space, the world's space powers have unanimously settled on chemical rockets as the best way to launch astronauts. The question that engineers are still debating is: what is the best way to achieve them?

Boeing and SpaceX, which through NASA's Commercial Crews program are due to send astronauts to the International Space Station next year, were asked to respond to the two basic problems of space flight with ingenuity, economy and technology for the challenges cosmic at the front. . However, one of the most visible elements of their privately designed spacecraft will be traced back to the last century: they are shaped like capsules, relying on their high-strength, blunt shapes and a pair of parachutes to slow them down to an orbital speed of 17,000. at a speed that human occupants can survive when they hit the Earth's surface.

The space shuttle should end all this when it took its first flight in 1981, providing airplane-like comfort during its gentle touch on the runway. And by creating the next generation of space transportation, SpaceX really tried to lean toward the future. Elon Musk and his team pressed for a new type of landing, which depended on propellant rockets rather than parachutes, to decelerate the ship and extend legs to balance it at landing – a so-called propulsive landing. "This is how a 21st century spacecraft should land," Musk boasted in 2014, "anywhere on Earth with the precision of a helicopter." SpaceX got a suitable landing for its payload rockets – the first stage of the Falcon 9 regularly, and impressively, lands on an oceanic barge or back to Cape Canaveral. But such forward jumps with living astronauts on the inside require time and money that NASA was unwilling to commit to a mission whose main selling point was the economy. At least that's what spies guess from the Musk's laconic abandonment of the approach in 2017. Then the parachutes came out again.

Nasa's spatter of astronauts acquired a nostalgic, if not mythical, tone of a half-century distance. But they were hairy subjects in real life. Gus Grissom nearly drowned after the second Mercury flight in 1961 – a famous incident that became most famous for his inaccurate portrait in the 1983 film The right thing. The following year, Scott Carpenter landed 250 miles from the course and spent three hours in a lifeboat before being rescued by the USS Intrepid.

Splash adventures continued after lunar missions, even after more than a decade of fast-paced technological progress. The crews of the 1974 Skylab 4 mission and the Apollo-Soyuz Test Project, a year later, ended up facing the ocean for a while as the heavy seas picked up their parachutes and turned the landing craft. Apollo-Soyuz's problems were aggravated by an escape leak in the cabin that required astronauts to pick up oxygen masks, which were harder to reach while they were upside down. The crew member, Vance Brand, fainted during the fight, and one of his crew had to put his mask on him. In both cases, inflatable "balancing balls" outside the capsule worked as planned. The ships turned back to the surface and the astronauts emerged relatively unharmed.

Of course, there is an alternative to landing at sea: the land landing, which the Soviet and Russian space program has been doing from the beginning. The Soyuz spacecraft, launched for the first time in 1967 and still high, returns to Earth in the vast and flat steppes of Kazakhstan. Not the most comfortable experience, ex-passengers report. "It's like a series of explosions followed by a car crash," says Michael Lopez-Alegria, a former NASA astronaut who returned from the International Space Station on a Soyuz in 2007. "After seven months in space, this does not happen . feel good."

Soyuz had a near-fatal accident in 1976, when the re-entry capsule exploded and landed on a partially frozen lake – five miles from the coast at night, in the middle of a blizzard. Rescue workers, who arrived on the partially submerged ship nine hours later, did not bother opening the hatch for two hours because they assumed that the cosmonauts had frozen to death. The resilient Soviets survived, though they never flew again.






Ah, the good days, when American astronauts landed on the ocean and Russian cosmonauts ashore. Photo: Apollo capsule without cap in 1968

(NASA)

A Soyuz fires its retrothrusters just before impact. Soon, US capsules will do both.

(NASA / Bill Ingalls)

When a capsule loses its mark on land, astronauts are not left for hours to rise and fall in the waves. But they can get cold. Here, a Soyuz rescue team meets the crew on a nebulous day in Kazakhstan.

(NASA / Bill Ingalls)

However, Lopez-Alegria prefers to return from space to terra firma, given the choice. "Landing on the water seems to make a big flop, so I'm not sure the impact is much smaller," he says. "And then I think I'd be happier on land than moving around in the ocean." Ken Bowersox, another Soyuz veteran, also thinks the earth is safer than water. "On land, you may have some forced landing and still crawl out of the vehicle," he notes. "If things do not work out in the water, it can get exciting really fast." Describing Bowersox's Soyuz re-entry in 2003 as a "somewhat difficult landing" may be a euphemism. The capsule diverted to a ballistic landing that took her hundreds of miles from the target. But "we only wait a few hours," he recalls. "In the water, it would have been much less comfortable." As for impact, Bowersox compares it to the aircraft carrier landings he practiced as a Navy pilot. "It catches your eye, but it's no worse than a carnival ride," he says.

NASA studied ground landing at various points in the pre-transport era, but rejected it for several reasons. At the time, the agency concluded that the United States did not have a flat, vast and empty area in contiguous states. At least when compared to the open, undifferentiated space of the Kazakh plain, even the Southwest desert could not compete with its canyons, plateaus, and remote towns and reserves. The descent targeting was not accurate and reliable enough. What the country had was a lot of open water: abundant access to two oceans, a coastal launch site and the existing maritime infrastructure to recover astronauts from the water.

Another significant consideration in these terrestrial studies was the spacecraft's weight. A landing in the water can end with a dive, but the liquid still has a bit of a donation; returning ashore requires some extra recourse to compensate for the difficult stop, such as the retro rockets that the Soyuz fires when it is several meters off the ground for a final brake in the seconds before impact. However, this equipment is a heavier vehicle, and in the early 1960s, time-pressed NASA's brain confidence did not believe they could carry all that weight to the Moon (see picture on the side).

But technology improves and goals change. Thus, Boeing revisited the land landing issue when it began designing its commercial vehicle, the Starliner, by 2010. "Returning ashore has an edge over the sea in having immediate access to the crew and all cargo on board," says Michael McCarley, a Boeing career man who worked on the space shuttle during his final flight before moving on to the Starliner project as a reentry chief engineer. But the weight of this type of capsule is still a problem – or, as McCarley calls it, "the challenge of the masses."

Soyuz may have solved its massive challenge in the year the Beatles recorded Sergeant PepperBut the Russian ship can only cram in three astronauts – half the crew of a space station. One key to the expanded seven-passenger land-based vehicle was to replace retro rockets with airbags. The Starliner will have six of them (one seventh in the center, unfolds only for an emergency landing). They are inflated with nitrogen and oxygen like those of automobiles, but designed as bicycle tires with discrete inner and outer layers. The outer bag has openings that release the pressure on the landing, while the inner tube remains firm. Hopefully.

The airbag system is not only lighter than Soyuz rockets, but should be easier on bodies already depleted for half a year in space, says McCarley. Ken Bowersox is an enthusiast. "If you look at people jumping from buildings and landing in airbags, that should be a very reasonable landing," he says.

Then there's McCarley's personal project: the seat. One way or another, a space capsule returning to Earth on parachutes is decelerating through the atmosphere by about 4 Gs before its sudden stop, says Lopez-Alegria, who is still on NASA's human exploration advisory board. This compares to a tolerable 1.5 Gs for the glide-to-a-landing space shuttle. But the impact on astronauts' bodies depends, literally, on where and how they sit. Or lie, in fact, as the backbone of a human being and other vital organs are not designed to absorb 4 Gs in a vertical position. Soyuz passengers already land reclined, with an individually designed seat cover. But McCarley was determined to improve this with modern ergonomics. He started with a pile of plywood in his garage.

"The overall concept for the seat did not change the plywood model, but we added some more advanced materials," says McCarley. The company also added 3D printing technology to mold an entire custom seat for every Starliner passenger. Given the compact space available, this involved the intensive study of human body types.

McCarley, who is a stocky 6 "1", and Starliner systems engineer Melanie Weber, who is just under a meter and a half, have modeled themselves to the outer limits of allowable size.Deeper into the nuances, the engineers worked to accommodate a range of body types, which they gave with names like The Orangutan ("long arms that can practically reach the capsule," McCarley explains), or the T-Rex (broad trunk with short arms). designing the range of extremes, the team will be better able to adapt each seat using an astronaut's body scans.

The Boeing team also wanted to improve the parachutes of the Soyuz era. For reasons now lost in the scientific history of the Cold War, the Russian ship's parachute series – pilot, drug and finally main ramp – opens from one side of the capsule, followed by the pyrotechnic release of a mooring system that forces the parachute. capsule to hang down. Lopez-Alegria describes the result as "a rather violent side-by-side movement, like Mr. Toad's Wild Ride." Boeing promises to smooth the process with two drugged drutes for symmetry, followed by three main kicks for extra stability, not to mention redundancy.

As for the location of the capsule, the Starliner team is more comfortable with precision landing than the NASA engineers. The company has a list of five locations in the West – two at the White Sands Missile Range in New Mexico, the Dugway Proving Ground in Utah, Edwards Air Force Base in California, and Wilcox Playa in Arizona – from which they will choose primary and local backup before the end of each mission. Land crews have searched long forgotten telephone poles and other obstacles, and conducted extensive environmental and cultural research to ensure both the safety of astronauts and the integrity of the land. The Dugway Proving Ground, for example, was established by the Army during World War II to test chemical and biological weapons, and is also an archaeological treasure trove of Native American artifacts dating back 13,000 years.






When Starliner astronauts – Eric Boe (seated on the left), Chris Ferguson (sitting on the right) and Nicole Mann – return to Earth after the first manned mission next year, they will be protected by seats made entirely of their bodies scans

(NASA / Bill Ingalls)

Instead of the heavy-duty Soyuz retrothrusters, Boeing has designed six lightweight airbags for the Starliner (which are being tested at the Langley Research Center), which should make a slightly more comfortable leap in its fall to Earth.

(NASA)

In Nevada, Boeing tests the landing system on its Starliner capsule.

(Boeing)

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While Boeing engineers thought hard about the details of their capsule landing on hard ground, SpaceX began its dream job with Mars. In January 2011, the company published a 15-second futuristic video describing a trapezoidal spacecraft, making a vertical landing without rushing, without parachute, propelled by flames coming out of the four corners of its base at angles of approximately 30 degrees. Elon Musk, in the narration, describes how "a propulsive landing with equipment, type [how Apollo 11’s] Eagle landed on the moon. It sounded really cool.

But those SuperDraco thundering flames, as Musk subsequently named them, were aimed more at dropping a 14,000 pound Crew Dragon capsule into a helipad anywhere on Earth. SpaceX insisted they could bring a similar mass ship safely to the surface of Mars, where the atmosphere is too thin to land anything of that weight by parachute. The heaviest object that crashed there today was NASA's Curiosity rover, which had about a seventh of that mass and, of course, no fragile human passenger.

SpaceX unveiled a Crew Dragon prototype in 2014 with high hopes for its prospects on two planets. In 2016, he posted a video of a test model hovering confidently several feet above a platform in Texas. Then Musk canceled. While the Crew Dragon was technically capable of landing propulsively, he told a research and development conference at the space station in July 2017, it would take a tremendous effort to qualify him for safety. In addition, he had already guessed a much better "approach to landing on Mars, whose details he kept secret. The capsule still carries SuperDraco engines, but they should only be used in case of a miscarriage. (See "Aborting!" Oct./Nov. 2018.) A routine Rotorcraft Dragon seems destined to become a footnote to exploration history, though SpaceX continues to work on technology for its other vehicles, including the next generation of BFR. rocket – an untested space shuttle that promises to carry up to 100 passengers to the moon or beyond. The first paying customer of that trip, Japanese billionaire Yusaku Maezawa, was announced in September.

Fortunately, the company had a proven Plan B to take the crew to the space station. While SpaceX was tinkering with the futuristic system for a manned ship while this magazine went to press, its cargo ship silently performed 15 successful missions to and from the space station, the capsule falling without incident. So far, the company has been able to reuse four of the capsules, despite the salt water bath.

The Crew Dragon is about 50% heavier than the load model, so SpaceX is compensating the extra mass with a four-parachute system that looses symmetrically above the vehicle, delivering more drag than the classic triangle that returns above of the capsules of the 1960s. More than Boeing Starliner too, a company statement implies: "The Crew Dragon parachute system is the most efficient system ever designed in terms of packing density and aerodynamic braking ability. "

An even more striking difference from the days of old will be the modest flotilla that SpaceX implements to recover the Dragon astronauts at sea. The published plans require a single 164-foot GO Searcher, with support of several inflatable boats that can maneuver closer to the speckled capsule. O GO Searcher will be equipped with a heliport to transport the astronauts quickly to the coast if necessary.

This is a dramatic contrast to the US Navy's fleet of vessels that sailed to meet space travelers from the 1960s and 1970s. No fewer than 24 warships waited for John Glenn's squirt after the first US orbital flight in 1962, with the Air Force in anxious reserve. Landings became more precise quickly, however, and the welcome party fell to four ships on the last Apollo moon flap in 1972. Thus, SpaceX's stripped-down rescue team was not as minimalist as it might seem. (The company has a more elaborate system, through a partnership with the Air Force parachute teams, for the recovery of the astronauts after the launching abortion.)

SpaceX is also looking forward to expanding its reusable technology to Crew Dragon. The team has acquired extensive experience in water fence and corrosion prevention of four cargo ships. But now SpaceX is only approved to pilot a crew with new spacecraft, creating a somewhat ironic situation in which archrival Boeing deploys a reusable capsule before SpaceX. Rocket observers are guessing that the assault will be temporary.

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Human spaceflight inevitably involves living in the worst possible scenarios. "I'm always thinking, is there something hidden that we do not know?" Says Mike McCarley of Boeing. "I looked behind each door and in the back of all the cabinets? It is a personal neurosis, but also a professional neurosis. "Since the impetuous space race of the 1960s, human spaceflight also involves inevitable delays and frustrating corrections midway – from adjustments that only engineers can understand to harbor whole promising systems. such as SpaceX's propulsive landing scheme. At the beginning of the program, the business team's missions were optimistically targeted for 2015. Currently, they are planning for mid-2019.

None of this should obscure the fact that private contractors are gaining confidence from NASA and the astronauts of the past and the future, in whatever way they go. "For me, I do not care. Both will work, "concludes Ken Bowersox. "Descending on land or sea is more of an economic decision."

Delays in the program also do not invert a clear direction: commercial flight, retro landing systems, and so on point the way for an exciting new chapter in space exploration, where private companies take on futuristic projects from asteroid mining to colonization of Mars. "This is revolutionary in many ways," says Lopez-Alegria. "This is the first time the government has loosened the reins of the size of the washer to be used. It will be a kind of rebirth. "This is a door that he and many others are eager to go through. The current Lopez-Alegria program is responsible for Axiom Space's business development, which wants to build a privately-funded successor to the space station at an estimated cost of $ 1.5 billion.

First, though, will come the new commercial vehicles and their dramatic parachute returns – not just to Earth, but for the first time in almost a decade, to their own country.

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