Why Don't Space Suits Go Rigid When Astronauts Go On Spacewalks?

Why don’t space suits inflate like a Michelin Man when on the Moon or outside the Space Station?
In this photo, Astronaut David A. Wolf, STS-112 mission specialist, anchored to a foot restraint on the Space Station Remote Manipulator System (SSRMS) or Canadarm2, carries the Starboard One (S1) outboard nadir external camera. Image credit: NASA

In this photo, Astronaut David A. Wolf, STS-112 mission specialist, anchored to a foot restraint on the Space Station Remote Manipulator System (SSRMS) or Canadarm2, carries the Starboard One (S1) outboard nadir external camera. Image credit: NASA

Originally posted on Forbes!

They very easily could! If you had a poorly designed space suit or an overly pressurized suit, an astronaut could very easily find themselves immobilized, unable to contort their suit into a useful position. With the inside of a suit set to normal sea level pressure, and the outside of the suit set to the vacuum of space, a fabric suit with no hinges will very quickly stiffen into an inflated posture, and would be very difficult to bend.

In fact, this very situation posed a serious problem for the first spacewalk, conducted by Alexey Leonov, whose suit inflated, and became an obstacle to re-entering the airlock of his spacecraft. With the airlock too small to accommodate a totally puffed-up spacesuit, Leonov had to manually depressurize his suit so that he could bend his arms and legs enough to creep back into the spacecraft. This is not a recommended path to getting around in space; it gave Leonov a very rapid depressurization experience (like “the bends” that divers can experience if they rise from the crushing depths of the ocean too rapidly): hardly good for you and certainly painful.

NASA invited the public to vote on three cover layer designs for the Z-2 prototype suit, the next step in NASA’s advanced suit development program. By using Luminex wire and light-emitting patches, this design puts a new spin on spacewalking standards such as ways to identify crew members. Image credit: NASA

NASA invited the public to vote on three cover layer designs for the Z-2 prototype suit, the next step in NASA’s advanced suit development program. By using Luminex wire and light-emitting patches, this design puts a new spin on spacewalking standards such as ways to identify crew members. Image credit: NASA

There are two solutions that let you avoid inflation of a suit; one is to reduce the pressure inside the suit, and the other is to build your space suit with hinges, so that you never have to compress the air inside the suit by folding it over on itself. Current space suits usually try to do both, which helps makes the process of leaving the home sanctuary of the space station a little easier on our astronauts.

Instead of being pressurized to one atmosphere at sea level, the current iteration of space suits for spacewalks are typically pressurized to only about a third of that. Having a smaller internal pressure means that the suit is less rigidly inflated when “outside”, in space. However, it does mean that the astronaut has to spend some time getting used to this reduction in pressure, and making sure their blood is still getting a safe amount of oxygen.

Once they’re outside, though, even with a smaller internal suit pressure, the astronauts might still struggle to bend the suit. If you look at the sleeves on a long-sleeved shirt, if you bend your arms, a bunch of fabric folds over onto itself at the inside of the elbows. This is usually not an inconvenience to us, but that’s because the air inside our sleeves is the same pressure as the air outside our sleeves. In space, each crinkle in the suit changes the volume of the suit; any change in volume means that the air pressure changes. If you increase the number of folds when you bend your arms, you decrease the amount of room the air has to fill, and the pressure will increase. The solutions here are to either build a huge number of folds into the suit, so that any bending motion won’t change the internal volume, or to make the suit contain a large number of swivel points.

Developed at NASA Ames Research Center in the 1980s, the AX-5 high pressure, zero prebreathe hard suit was developed. It achieved mobility through a constant volume, using a hard metal / composite rigid exoskeleton design. Image credit: NASA

Developed at NASA Ames Research Center in the 1980s, the AX-5 high pressure, zero prebreathe hard suit was developed. It achieved mobility through a constant volume, using a hard metal / composite rigid exoskeleton design. Image credit: NASA

An extreme version of the swivel point approach is the hard-sided prototype suits that NASA developed in the 1980s. This suit was almost 100% hinge, but the principle was that you would never have to bend the suit - the hard-sided spacesuit would simply be able to reshape itself into the needed configuration. Because there’s no bending, the suit could be pressurized to something closer to sea level air pressure, which means getting into and out of it will take less preparation.

The Z-1 is NASA's next generation spacesuit, a prototype of which is pictured at the Johnson Space Center. Image credit: NASA

The Z-1 is NASA's next generation spacesuit, a prototype of which is pictured at the Johnson Space Center. Image credit: NASA

The current space suits, along with the next generation of suits, are mostly made of flexible fabric, but take the “insert all the folds you’ll think you’ll need” approach, with tactically placed folded segments at elbows, knees, and shoulders. These joints, along with the lower air pressure in the suit, allows the astronauts to move with most of the dexterity they’re used to, and perform the repairs, replacements, and other adjustments that the ISS periodically requires! But if you were to just make an airtight suit, with no particular hinges, and pressurize it to the air pressure at sea level, you would absolutely have an inflation problem.

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Could We Protect Mars-Bound Astronauts With A Magnetic Bubble?

Could a synthetic magnetic bubble, like a mini-magnetosphere, protect a crewed mission to Mars from cosmic radiation, and would the energy cost be prohibitively high?
A NASA mission reveals how gases in Mars' upper atmosphere are stripped away by the sun's solar wind. Image credit: NASA's Scientific Visualization Studio and the MAVEN Science Team

A NASA mission reveals how gases in Mars' upper atmosphere are stripped away by the sun's solar wind. Image credit: NASA's Scientific Visualization Studio and the MAVEN Science Team

Originally posted on Forbes!

As much as some folks are keen on sending people to Mars as soon as possible, it’s become obvious that protecting any astronauts from an unsafe level of radiation before they even get to Mars is going to be a tricky business.

There are two main problems for astronauts leaving our home planet; one is cosmic rays, which are usually turbo-speed protons from outside of our solar system. Some cosmic rays are blocked by our Earth's magnetosphere, and the remainder are usually stopped by our atmosphere. The other problem comes direct from the Sun itself; the Sun also flings electrons and protons in our direction in the solar wind. The solar wind is mostly stopped by our magnetosphere, but if you’re going out a bit further, we won’t have that protection.

The solar wind is a stream of particles, mainly protons and electrons, flowing from the sun's atmosphere at a speed of about 1 million mph. Image credit: NASA's Scientific Visualization Studio and the MAVEN Science Team

The solar wind is a stream of particles, mainly protons and electrons, flowing from the sun's atmosphere at a speed of about 1 million mph. Image credit: NASA's Scientific Visualization Studio and the MAVEN Science Team

The solar wind is usually relatively easy to protect yourself from; with a slightly thicker wall than the bare minimum on your spacecraft, you can usually protect your crewmembers from a solar wind related battering. However, cosmic rays are harder to stop. The protons which make up cosmic rays typically have more energy to them, so shielding has to be more robust. The second problem with cosmic rays is that sometimes they’re more than just a proton; they can be an entire helium nucleus (two protons, and two neutrons), making them a projectile that’s both very high speed and four times the mass of a solar wind particle. These enormous cosmic rays can break apart, at an atomic level, the material they crash into, filling the interior of your spacecraft with radiation, which is not great for anyone trying to live in there.

Once a spacecraft leaves the Earth’s protective bubble, not only does the cosmic ray dose increase dramatically, but you’ve also got a much less protected place to deal with the solar wind. And if the Sun decides to unleash a solar flare in your direction, you’ve got an awful lot of protons coming your way from the Sun, in addition to the galaxy in general pelting you with helium nuclei.

Enlil model run of the July 23, 2012 CME and events leading up to it. This view is a 'top-down' view in the plane of Earth's orbit. Image credit: NASA's Scientific Visualization Studio, the Space Weather Research Center (SWRC), the Community-Coordinated Modeling Center (CCMC), Enlil and Dusan Odstrcil (GMU), Leila Mays (CUA) and Janet Luhmann (UCB) and NASA's Scientific Visualization Studio.

Enlil model run of the July 23, 2012 CME and events leading up to it. This view is a 'top-down' view in the plane of Earth's orbit. Image credit: NASA's Scientific Visualization Studio, the Space Weather Research Center (SWRC), the Community-Coordinated Modeling Center (CCMC), Enlil and Dusan Odstrcil (GMU), Leila Mays (CUA) and Janet Luhmann (UCB) and NASA's Scientific Visualization Studio.

Unprotected, a solar flare can rapidly give you radiation sickness, which makes you tired and also makes you vomit. Fortunately for all involved, most spacecraft have thick enough walls that the crew should be protected from solar flares, but it’s generally considered good practice to reduce all possible risks. On the other hand, cosmic rays are not so easily stopped.

Because cosmic rays are fundamentally a charged particle, using a miniature magnetosphere surrounding the spacecraft would be an effective way of keeping them away from both your crew and the walls of the spacecraft; if this could be built into a spacecraft, you wouldn’t need to bulk up the outer surfaces of the craft for radiation protection. However, actually doing so is a bit beyond us at the moment. There have been a number of proposed magnet configurations developed, and a recent simulation of three different styles indicated that the magnetic shielding could, in fact, reduce the overall radiation dose an astronaut would receive. This is not a given, because to create such a magnetic field, you need to add extra stuff to your spacecraft; the more mass you have, the more stuff Galactic cosmic rays can bash into, filling your craft with extra radiation. However, these portable magnetospheres are only just in the design phase --the next big steps will be building them, making them lighter, easier to power and making sure they work they way we hoped they would. At this point, all we can really say is that it should be possible. We'll have to wait and see if it's also practical.

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In the future era of commercial spaceflight, will everyone need extensive training?

Sorry if this is a silly question. My knowledge of space is limited to what I’ve seen in sci-fi movies and shows. I was wondering if technology will eventually make it to the point where we can bypass the training that astronauts need to go through to go to space. I mean, if we ever plan on sending whole boatloads of people to other planets to colonize them, would every single person need to go through the same kind of training astronauts do today?



A very good question!

Astronauts go through very extensive training before they get to go to space (up to two years worth of training before they can go to launch), and even people who go up as “space tourists” still have to undergo pretty significant training. Sarah Brightman, for instance, plans to be on the ISS for 10 days; her training will be 9 months long, in addition to costing her several tens of millions of dollars.

As our space program advances, I would imagine that the training needed to go into space will decrease dramatically. If we use airplanes as a parallel, in the early days of airplanes, just to get on the plane you had to be highly trained in all aspects of operating, landing, and surviving failures. Effectively, if you weren’t performing a critical role in making the plane work (in other words, a pilot), you weren’t on that plane. But nowadays when you get on a plane, after a lot of development of the technology that goes into reliable planes, the majority of people on board are ‘trained’ in the sense that they will mostly try to ignore the instructions on how to put on the oxygen mask in case of cabin pressure loss. The pilots are functionally invisible to most of the passengers.

I expect that once space travel has advanced to the point where we can transport large groups of people, there will be less of a requirement that every person on the spacecraft will need extensive training. Obviously we would still need highly trained people to operate the spacecraft, but for the majority of people on board, they’d just need to know what to do in case of an emergency, much as we do now on planes.

The reason everyone needs so much training to go into space right now is because every single person on the craft has a vital role to play to make sure everyone gets up and down safely, and can complete the mission that needs to be done while in space. This is one of the reasons that the only astronauts on the space shuttle who weren’t extremely talented Air Force pilots were the mission scientists and payload specialists, and while they weren’t expected to be able to land the Shuttle, they were entirely responsible for making sure that the science happening in space was taken care of, and they’re usually the ones that wind up on spacewalks. Spacewalks (among other things) serve the critical purpose of repairing or maintaining equipment - either satellites, the spacecraft itself, or the International Space Station. This kind of repair is very technically challenging, so it requires the intensive years of training that the astronauts have to undergo.

However, if we’re transporting large groups of people, we will be able to move more people than just the mandatory operating crew, much as planes now do. While the operating crew will be able to take care of the flying of the ship and any repairs that need to be made, and the remainder of the people on board just need to avoid doing anything hazardous or dangerous to themselves or their ship. This will probably require a safety briefing (please do not poke holes on the ship, do not bring explosives on board, no smoking), but it wouldn’t require nearly the years of training it would require to be a pilot on that same spacecraft.

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