Half a century of space suit evolution

It was a big week for thinking about walking in space — and what the spacewalkers are wearing. 

The first all-female spacewalk took place this week outside of the International Space Station. And earlier in the week, NASA unveiled its latest version of a spacesuit designed for future moonwalkers. 

Even the private company Virgin Galactic showed off its suits for space tourists. They're strictly speaking flight-suits, not spacesuits, but they'll be worn during the company's short suborbital space flights. All this comes while the space community mourns the death of Alexei Leonov, the first spacewalker who showed that walking in space is not as easy as it looks.

A spacesuit is a one-person spaceship, providing all the necessary support to keep a person alive in the hostile conditions of space. It supplies air and provides temperature control to keep astronauts from frying or freezing; pressure to keep blood from boiling; communication; and incidentally protection from tiny and potentially lethal micrometeorites that fly through space at tremendous speed. All this, in a suit that must be flexible enough to work with tools while floating freely, or perhaps allow the wearer to climb down the ladder of a lunar lander, walk on another world and enable the person to do simple, if useful things like bending over to pick up rocks.

Spacesuits in the '60s

The evolution of the spacesuit has been a steady progression of improvements since Leonov floated out of his Voskhod capsule in 1965 and became the first human to be exposed to the vacuum of space. 

He almost died in the process. Without any pressure on the outside of the suit, the air inside inflated the one-piece garment like a balloon, so his hands came out of his gloves and feet rose out of his boots. The inflation not only made the suit stiff and difficult for Leonov to manoeuvre in, but the increased size made it too large to fit through the hatch of the spacecraft when he tried to get back in. 

Struggling with elevated heart rate and rising body temperature, his only choice was to let air out of his suit to make it more flexible. This put him at the risk of hypoxia, or lack of oxygen to the brain, and the bends, experienced by divers who rise to the surface too quickly.

Since then, suits have been improved to prevent similar situations, with the current versions on the space station involving a rigid upper body segment to which arms and legs are attached. This allows the suits to be mixed and matched to fit different body sizes, although astronauts must still work against stiffness in the arms when working in space.   

The new moon suit is equipped with bearings around the waist and the shoulders for more maneuverability, and hopefully, protection against moon dust.

Suiting up for a hostile space 

During the Apollo missions to the moon, especially the later flights that spend days on the lunar surface, astronauts found their suits became completely covered in fine dark dust that got into everything.

The dust comes from billions of years of bombardment on the lunar surface from objects large and small that have pulverized it into a powder many centimetres deep. Without weather to tumble particles about and round out their surfaces, moon dust particles have jagged edges, which makes them stick to everything and very abrasive. The astronauts were concerned that the dust would jam up the joints in their suits and get into electronic equipment when they crawled back inside their lunar module.

Future Mars explorers will likely need even more flexible and lighter suits because they will be walking around in a higher gravitational field than the moon.

The design of spacesuits illustrates how hostile the space environment really is. Without protection, the human body would not survive more than a minute or two in the vacuum, and even on Mars, the air pressure is only about one per cent of the pressure on Earth, and there is no oxygen to breathe. Colonists living on the red planet will need to put on a suit every time they take a walk outside. 

In fact, every planet and moon known will require a spacesuit, including the thousands found around other stars. In other words, the universe will kill you.

Eventually, another Earth-like planet will be found with an atmosphere suitable for humans, but that world will be light years away, totally out of reach with our current technology. That means for now, there is only one planet where humans can breathe freely — this one.

So next time you step outside, take a deep breath of fresh air and marvel at the fact that you are standing on the only planet we know of where you can do that without wearing a spacesuit.