The most interesting work, however, has to do with NASA’s next-generation space suit for astronauts traveling to the moon – the eXploration Extravehicular Mobility Unit, or xEMU. It is apparently the successor to the space suits worn by Neil Armstrong, Buzz Aldrin, and other Apollo astronauts when they set foot on the lunar surface half a century ago. But it also incorporates what we learned from EMUs used in orbit during the days of human exploration of the Space Shuttle and the ISS, as well as the hard lessons of Apollo. The goal behind Artemis is to have people who live and work on the moon. The new spacesuits will be essential to ensure that the experience is safe and comfortable.
“We’re very excited to get people back to the moon,” says Richard Rhodes, a NASA spacesuit engineer who works on the xEMU. “Our main goal is that the crew don’t even think about us. They don the suit and do their job – the science, the exploration – and don’t even think twice about their mobility or how efficiently they can work. It’s a tall order, but we’re trying to get as close as possible to it. We want to be invisible. ”
Here are some of the biggest innovations we can expect from xEMU.
“When you design a spacesuit, you want it to move freely and efficiently, with as little effort as possible, so that we can be as close as possible to the mobility of shirt sleeves,” says Rhodes. The goal is to limit the amount of bulk in the suit, as the more bulk the astronauts have to work hard to bend their joints, and it can quickly become exhausting.
The solution is to use bearings, because they rotate around a single point and ensure a constant volume. The older Apollo suits only used bearings in the arms, as it was essentially a versatile suit (used for both launch and entry, as well as moon exploration). It had to be light enough to handle all of these different situations, and too many bearings could have weighed it down.
The xEMU has lighter bearings and closer to the seals than those used for previous EMUs. Those at the shoulders should make it easier for astronauts to reach outside and lift objects while reducing the risk of upper body injuries. Finally, there are bearings at the waist, hips, thighs and ankles, creating much greater mobility in the lower body. “All of these together allow for mobility and movement with very low torque and low power consumption,” says Rhodes.
The suits also have a variable pressure system to give astronauts more flexibility when they need it. This should allow them to prepare faster in the suit when needed, but also to lift materials or kneel down to study things when the situation calls for it.
Hip mobility bearings in particular are a big deal for moonwalking (no, no this kind of moonwalking). Apollo astronauts did not spend much time on the surface of the moon during their missions, and much of the time they spent was largely just getting to know this new environment. They quickly found it difficult to move around normally in microgravity, and they were also very careful to avoid danger.
With such limited hip mobility, the stride was simply not possible. So they mostly mixed up; when they became more comfortable and more adventurous, they could manage a more slender gait to move faster. Trying to grab things on the ground required an awkward lunge.
The xEMU is supposed to encourage normal walking as opposed to jumping, and facilitate stable kneeling in one motion to work close to the ground – which wasn’t much of an option for Apollo astronauts. No need to search for objects anymore. This will make it much easier for astronauts to carry out valuable scientific work in the field, such as examining geological samples or setting up complex instruments.
A huge lesson learned from Apollo is that moon dust is terrible. The moon’s surface has not been exposed to the type of weathering of the earth’s geology. As a result, the lunar soil is very coarse and jagged, and it sticks to everything (yeah, I know I ring as Anakin Skywalker). It contaminates the inner layers of the garment and all parts that are supposed to come off, and causes general wear and tear on the exterior of the suits.
So, to avoid exposed spaces, designers minimized components such as disconnected zippers or cuffs, as well as seams where dust could seep into. “We’re looking more at a full garment that covers the entire assembly, with little features where you can still perform operational checks and disconnect things in an emergency,” Rhodes explains. “It’s like an entire shirt and entire pants that are all in one piece, with no breaks where dust can get inside.” And for areas where there are ruptures (like bearings), the team is working on developing and incorporating seals that must keep dust out.
XEMU helmets offer a wider field of view than Apollo helmets, with onboard lights to help illuminate dark areas. They will have a HUD (head-up display) so that astronauts can access important information while on the move. The high definition shoulder cameras will help to record the trips as if they were directly from the eyes of the astronaut.
The “Snoopy caps” used for communications are a fairly recognizable part of EMUs, but as most astronauts who have been on spacewalks can attest, they can quickly get drenched in sweat and their microphones don’t work. still fine after many hours. movement. The xEMU discards the Snoopy cap for an in-suit audio system, voice activated to automatically pick up sounds as they are spoken.
A common complaint among all astronauts who have been on an EVA is that gloves are a threat. Their bulky layers mean you lose a lot of dexterity, and you also don’t necessarily know how much pressure you’re using when grabbing something. Lack of circulation and moisture build-up can lead to nasty side effects, like brittle nails and even fungus. “Gloves are not a new challenge,” says Rhodes. “There is absolutely room for improvement.”
The main improvements Rhodes and his team are working on for xEMU are to ensure that astronauts’ hands are protected from extreme temperature changes and dust, and that they can handle lunar material safely. NASA is also looking to make it easier for them to accomplish simple tasks like grabbing tools and operating small equipment.
In 2014, Italian astronaut Luca Parmitano was on a spacewalk when his suit began to leak, flooding the helmet and nearly drowning it. Engineers later found that the contamination had caused water to backflow from the cooling system – a problem made worse by the fact that the water and the cooling loops were in such close contact. So the xEMU now keeps these loops completely separate to prevent another such emergency from occurring.
The xEMU also sports a new carbon dioxide scrubbing system that uses two different absorption beds (in this case, small lithium hydroxide cans that easily attract and trap carbon dioxide). While one is in use, the other can be exposed to the vacuum of space and emptied – so the carbon dioxide is constantly cleaned out without forcing the astronauts to come back inside to clean the absorption beds. Oxygen tanks are high pressure systems that are expected to deliver oxygen for longer periods of time than Apollo suits. The only limitation now for how long a person can stay in the suit, in theory, is the battery power.
Meanwhile, the xEMU retains some proven survival and security features. There is micrometeorite protection based on a similar design for current orbital EMUs. There is also thermal protection to withstand sudden changes in temperature (from -250 ° F in the shade to 250 ° F in the sun).
Personalized and scalable
Back in March 2019, NASA Cancellation of plans for the first women’s spacewalk because there weren’t enough properly sized spacesuits – only the larger ones were available.
It was a hard lesson in the need to make sure suits are designed correctly to accommodate people of all sizes. The agency decided that with xEMU they are leaving nothing to chance. Each suit will be tailored to the height, size and comfort of the individual astronaut and will aim to provide the widest range of motion for activities on the moon. If a moonwalk gets canceled this time around, it won’t be because the suits don’t fit, but the design of the spacesuits is still a work in progress. “There isn’t a lot of data on how it works on the lunar surface,” Rhodes says. Any kind of feedback will be fantastic. NASA intends to incorporate what it learned from the first Artemis missions to improve xEMU again and again – with the goal of creating something that will someday work on Mars.