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When Are Space Suits Necessary?
The vast majority of astronauts’ work is done inside the relatively safe environment of the spaceship. They use robots like Canadarm2 to remotely do work outside in the harsh thermal vacuum. Occasionally, though, external work needs to be done that requires direct human judgment or dexterity. When the need outweighs the risk, a spacewalk is planned. Spacewalks, or EVAs (Extravehicular Activities), are dangerous, physically demanding, and rare. Since Alexei Leonov did the first in 1965, just over 200 people, including the 12 moonwalkers, have ever performed an EVA—Chris was the 127th.
What Is an EVA Suit?
EVA suits are designed to protect astronauts from the hostile, deadly environment of space. They are pressurized with pure oxygen to one-third of sea-level pressure, can withstand the extreme cold and heat of the vacuum, and protect astronauts from the constant bombardment of tiny, high-speed micrometeoroids that fly through the solar system at 10 kilometers per second.
The suit has a portable life-support system in its backpack. It contains your oxygen-purification system, cooling system, radio, and battery power. On your helmet, there are cameras so that Mission Control can get a visual record of work you carry out, as well as lights for working in the dark. It also has a gold visor and sunshields to protect your face and eyes from the incredibly harsh, unfiltered Sun. On the chest there is a computer display and control module to run the suit and a purge valve to dump pressure if needed. The controls and labels on the front of the suit are oriented backward so that you can read them using the mirror on your suit’s wrist. Two hard clips on the front of the suit allow you to attach a metal frame that holds all your tools. During a spacewalk you keep yourself connected to the Space Station with at least one tether, clipped to the suit using locking metal hooks.
What Is the Standard Construction of a Space Suit?
Spacesuits are white to reflect the heat from the Sun. The suit itself consists of 14 layers of material, with each layer playing a different role in keeping you alive. The most fragile part of the whole suit is the palm and fingers of the gloves: they’re just a few layers thick to enhance dexterity. Since the gloves are so delicate, astronauts pause to check them for damage regularly during spacewalks. In order to have as much tactility in the hands as possible, there is a curved metal bar in the palm of the gloves that can be cinched tight with a strap across the back of the hand, to stop the pressurized glove from bunching up in the palm.
Unlike for the Apollo moonwalkers, the boots on your ISS spacesuit are designed to lock into a portable foot restraint, known as a PFR. PFRs can be located at various places around the outside of the ISS; once you’re locked in, both your hands are free to do work. Without it, you’d always have one hand busy just hanging on.
How Do Astronauts Train for Spacewalks?
Before you do a spacewalk there are years of training on suit systems, in virtual reality simulators, in vacuum chambers, and simulating weightlessness under water. Chris spent over 400 hours suited in the pool prior to his first spacewalk. In addition, you need to qualify on SAFER, the Simplified Aid for EVA Rescue. It is a jetpack, used as an emergency self-rescue system in the event that you were to detach from the ISS and go tumbling into space. SAFER is operated by a deployable joystick that fires puffs of nitrogen gas through 24 small nozzles to stop you from tumbling, and help steer yourself back to grab onto the International Space Station.
Are There Any Dangers Associated With Spacewalks?
EVA suits have to be checked for contaminants when they get back to the International Space Station to make sure that nothing foreign comes on board that will be a hazard to the health of the crew. The Apollo astronauts had to check for little pieces of unweathered, glass-like Moon dust, and current NASA astronauts check for ammonia from the cooling system of the ISS. Future suits will need to think about contaminant considerations: maybe the suits don’t need to come all the way back into planetary bases and can instead just attach to the outer wall of the astronaut habitat.
How Have Spacesuits Evolved to Serve Our Scientific Pursuits?
The Russians developed an early version of flight suits, the Sokol spacesuit, which Chris has worn during Soyuz rocket flights; the Sokol spacesuits are still in operation today. The last decade has seen many technological advances in space exploration. SpaceX CEO Elon Musk plans to send civilians to space one day; for now, the autonomous SpaceX ship Crew Dragon will carry NASA astronauts to the ISS. NASA’s commercial crew program and Mars program are also pushing the boundaries of space exploration. Thus, scientists are hard at work developing new spacesuits that can act like a second skin for astronauts and civilians alike.
For travel to Mars, astronauts could expect to be in space for nine months, minimum. We’ve learned from the ISS that extended weightlessness takes a toll on the human body; there are significant impacts on balance, blood pressure regulation, bone density, and sometimes vision After nine months of travel, once future astronauts get to Mars, there won’t be a ground support team to assist after landing. Depending how long crews need to adapt under Martian gravity (38 percent of Earth’s), the landing ship may need to function as a rehab facility. The weight and configuration of the Martian spacesuits will also have to allow for this adaptation period. In addition, the natural environment on the surface of Mars is deadly for human life; very low air pressure, no oxygen, 96 percent carbon dioxide, and high radiation. The habitat and spacesuits will need to protect the crews from this.
As Chris says: “It’s not really a suit. It’s more like a one-person spaceship—completely self-contained and different from the ship you crawl out of.”