FFIXING PANELS on the International Space Station (ISS), it’s a bit like fixing a car while wearing stiff oven mitts and standing on a skateboard. At least that’s how Kate Rubins, astronaut at Nasa, the US space agency, describes it. And she spent 300 days orbiting the Earth aboard the station, so she should know that.
Today’s bulky spacesuits weigh (or, for pedants, have a mass that is) nearly a third more than those sported by the Apollo astronauts who walked on the Moon in the 1960s and 1970. To complicate matters further, free fall from orbit does not have the damping effects on Newton’s first and third laws of motion (things move forever unless prompted by a force, and every action causes an equal and opposite reaction) which are offered by the Gravitational Field and solid surface of the Moon. Spacewalkers therefore have to think much more carefully about the consequences of their actions than Moonwalkers.
Add to this that most of the spacesuit systems in use today were designed in the early 1980s, which leaves plenty of time for their flaws to become apparent (in 2013, for example, an Italian astronaut on the ISS nearly drowned when more than a liter of cooling water accumulated inside his helmet). Add again that Nasa hopes to return astronauts to the Moon at some point in the 2020s and it’s clear the time is right for an upgrade. Nasa has a long list of features he would like to change or add. But Chris Hansen, head of extravehicular activity at the agency, says the immediate goal is to develop suits that allow far more body movement than the rigid suits which, as he puts it, made “jump like rabbits and fall”.
NasaThe quest for new costume designs did not go well, however. In August 2021, Paul Martin, its inspector general, concluded that 14 years and $420 million had been spent for meager results. Martin also stated that despite Nasa‘s plans to double that sum over the next few years, it still wouldn’t produce spacesuits in time for a moon landing then scheduled for 2024 (and now postponed to 2025). So, once again learning a lesson it really should have heeded by now, the agency hands over the design of suits to the private sector. The idea is to come up with something that can be adapted for use both in orbit and on the lunar surface. The winner will be announced next month.
As Dr. Hansen’s remarks suggest, an important criterion for success in this competition will be the flexibility of a spacesuit. One of the competitors is Astro, a combination offered jointly by three companies: Collins Aerospace, of Charlotte, North Carolina; I WILL SEE Dover, from Newark, Delaware; and Oceaneering, of Houston, Texas. Astro makes extensive use of Vectran, a synthetic fiber that is stronger than the Kevlar used in bulletproof clothing. This is made from a liquid crystal polymer which gives it both the strength and the necessary flexibility.
Wearers of such a suit should be able to reach and lean, gestures that would be impossible in today’s spacesuits. According to Dan Burbank, a former astronaut who helped assemble the ISS in orbit and who is now a technologist at Collins, they could even perform push-ups, at least when gravity-bound to the Earth’s surface.
A version of Astro designed for Moonwalks would allow hikes of perhaps 10 km, a distance that dwarfs those managed by Apollo astronauts. This lunar hiking kit would be fitted with special boots and a “breadcrumb” display on its face shield to show the occupant where it had been – and therefore, importantly, how to get home.
For spacewalks in Earth orbit, however, some people question the need for suits. Instead, they offer miniature spacecraft equipped with thrusters and robotic arms. Genesis Engineering Solutions, a Maryland-based company, is going down that road with what it calls the One-Person Spacecraft (SPS). The thrusters use compressed nitrogen, although in an emergency they can also draw from the craft’s air tanks. The arms were originally designed to defuse bombs, making them far more dexterous than an astronaut’s gloved hand; they can be controlled either by the space walker or by a remote operator. If all goes well the SPS will be used on Orbital Reef, a commercial space station being built by companies including Blue Origin and Sierra Space, and slated for launch in the late 2020s.
the SPS, believes Genesis, offers several advantages over conventional spacesuits. On the one hand, no airlock is necessary to allow the entry and exit of a space station. Instead, the craft docks directly to the station, so the two share air until the hatches between them are closed. This means that a pilot can enter and exit a SPS with little fuss. In contrast, for an adapted spacewalker to exit and return to the mothership, an airlock must be pumped out and then pumped back in. Since pumping is never completely efficient, it inevitably leads to leakage of part of a station’s air supply.
Another key difference is that a spacecraft can operate at atmospheric pressure. However, pressurizing a suit to this extent increases its rigidity, making its gloves in particular so rigid that they are useless for manual tasks. The pressure inside a spacesuit is therefore normally maintained at around one-third of an atmosphere. But that wouldn’t provide enough oxygen for an astronaut to breathe if standard air was used. So pure oxygen is used instead.
One consequence of this pressure drop is a risk of decompression sickness, in which nitrogen gas exits the bloodstream in painful and dangerous bubbles. Thus, before dressing, spacewalkers must undergo a so-called pre-breath of pure oxygen to purge the blood of nitrogen. An atmosphere of pure oxygen is also a fire hazard. It is not a theoretical risk. Three Apollo astronauts were killed by fire during a ground test in 1967 because their capsule contained such an atmosphere.
Spacesuits also present a third safety hazard, according to Brand Griffin, who runs the SPS efforts at Genesis. He says the shielding of a SPS provides protection against fast moving debris and micro meteoroids that would puncture a suit. If this happened, the vacuum of space would cause the astronaut’s bodily fluids to vaporize. And yet another advantage of a spacecraft is that, if a pilot were somehow incapacitated, its thrusters could be remotely controlled and docked to the mothership more easily than a spacewalker could be brought back into an airlock.
The downside of miniature spacecraft is the price. A SPS will cost, according to Genesis, nearly $70 million, or about four times the price of a spacesuit. But lower running costs can offset those upfront expenses. With tasks such as fitting a suit to the astronaut who will wear it (because they are not custom-made items), donning and doffing, and sterilizing its interior after use, a single exit in the space requires approximately 63 hours of work on board the ISS, not to mention the excursion itself. To get an idea of the expense involved, consider that the billing rate for a Nasa astronaut services on the ISS is $130,000 an hour. Blue Origin, the moving mind behind Orbital Reef, believes that once these costs are factored in, a SPS will end up being the cheapest option.
Adapted spacewalks are, anyway, so dangerous that Nasa discourages operators of planned commercial space stations like Orbital Reef from committing to it. As for space tourists, spacewalks have always been out of the question, no matter how dazzling the experience. the SPS will change that, says Brent Sherwood, manager of advanced development programs at Blue Origin. It provides automated “tourist-proof” excursions as part of a space vacation package.
Even if it works as expected, however, the SPS won’t end the need for space suits. Gateway, an international space station in lunar orbit, slated to begin assembly after November 2024, was designed for spacewalks to take place in suits, not single-astronaut spacecraft. Orbital Reef will, for its part (and despite Nasaskepticism), support adapted spacewalks as well as SPS. This system, after all, has not yet been proven.
Also, spacesuit technologists have other ideas in mind. I WILL SEE Dover, for example, plans to simplify adaptive spacewalking by providing life-saving assistance via an umbilical cord. This would limit mobility but greatly reduce costs, says Dan Klopp, the company’s business development manager. Suitports are also promising. With these, an astronaut would climb into the back of a spacesuit strapped to the outside of a vehicle. Once the spacesuit and vehicle were sealed, the suit could be detached with no airlock required, similar to the SPS.
Above all this, it must be admitted, is the question of whether spacewalks and Moonwalks by people really achieve everything that robots (remotely controlled or fully autonomous) cannot. To ask that, however, is to question the whole rationale for crewed spaceflight. And that would never do, would it? ■
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This article appeared in the Science and Technology section of the print edition under the title “Suited, rebooted”