Alexei Leonov, first space walk

The problems of spacesuits 50 years after the first spacewalk

The first spacesuit almost became Cosmonaut Alexei Leonov’s bodybag. Fifty years on, the modern spacesuit is once again in for a radical restyling.

The first spacesuits, developed in the late 1950s, were adaptations from garments worn by high-altitude aircraft pilots. When it came to venturing outside a capsule and into the vacuum of space, early prototypes proved less than ideal. On 18 March 1965, Soviet cosmonaut Alexei Leonov became the first man to ‘walk’ in space. He squeezed into the cramped airlock of his Voskhod capsule and pushed himself outside. For ten minutes he enjoyed the exhilarating sensation of floating, weightless, as the Earth rolled by underneath him. “Night was becoming day. I could see a vast panorama of the Mediterranean, Greece and Italy. Ahead was Crimea. My heart was racing!” he told me in 1997, during an interview for a film. He “felt insignificant, like an ant, compared to the immensity of the universe. At the same time, I was very strong, and special. I was the first to walk in space as the representative of humanity.”

At this high point of Leonov’s experience, the experimental nature of his outfit became apparent. Lacking a proper system to eliminate excess body heat, the suit’s interior became dangerously hot. Even so, Leonov was still enjoying his expedition when, after ten minutes, his cosmonaut colleague Pavel Belyayev radioed from inside the capsule that it was time to re-enter the airlock. “I was reminded of my mother, calling me back into the house after play,” Leonov recalled.

It was only now that he began to worry. “My feet were no longer in my boots, and my fingers were pulled back a long way short of the gloves.” Pressurised from within, his suit had swollen in the vacuum until it resembled a balloon. Leonov was in danger of being stranded outside his ship, because he had become too bulky to pull himself back into the airlock. His solution was drastic. He loosened some of the suit seals and released enough air to reduce the ballooning. Throughout this terrifying manoeuvre, he kept the bad news to himself. “If I had told the controllers on Earth, there would have been a commission of inquiry to decide the procedure, and then my life support would run out. I thought it best not to worry them.”

The partial decompression caused Leonov considerable pain, but he managed to squeeze himself back into the spacecraft. His problems weren’t over yet. “We had serious control difficulties during our return to Earth,” he told me. “The automatic systems did not work. We had to calculate our retro rocket firing manually. Then the rear equipment module did not separate properly, so we were spinning violently when we came down into the atmosphere.”

Cosmonauts in the 1960s liked to say, “If your altitude is greater than zero and your velocity is greater than zero, there’s a risk.” Like all such maxims, there were exceptions. Leonov and Belayev got really worried when both values, altitude and velocity, were at zero: the condition in which most cosmonauts would think themselves safe. “We landed a long way from our designated region, in a remote Siberian wilderness of birch trees,” Leonov explained. “We opened the hatch and then wished we hadn’t because of the wolves. Maybe they saw our parachute. Anyway, they were smart. They knew that something tasty had fallen from the sky.”

American astronaut attire

On June 3 1965, nearly three months later, Nasa astronaut Edward White made the first American spacewalk, drifting on the end of an umbilical cable outside the Gemini IV capsule. Just as Leonov’s suit had done, White’s also swelled in the vacuum, and he found it hard to move his arms and legs. Fortunately, Gemini’s hatch was large enough to let the fattened spaceman back in. White described his recall to the capsule as “the saddest moment of my life”. Despite this success, Nasa clearly had some work to do on the suit’s design.

The space suit sported by Nasa’s Apollo lunar astronauts between 1969 and 1972 did not suffer from ballooning, but maintained a constant volume when exposed to a vacuum. The upper torso, the arms and legs were strengthened with reinforced nylon fabric that did not stretch when inflated. Rubberised bellows at the shoulders, elbows, hips and knees allowed an astronaut to bend his arms and legs, although he had to work hard against the stiffness. Rather than walking in conventional strides, the moon men discovered that ‘skipping’ was easier, because they didn’t need to bend their knees so much. Bending at the waist was almost impossible. Long handles on the soil sampling tools proved useful. It seemed there was only so much freedom of movement that any spacesuit could permit.

Technological tweaks aside, little has changed in the fundamentals of suits for spacewalking. Astronauts working outside the International Space Station (ISS) move their legs as little as possible, relying instead on handholds to clamber around the orbiting outpost, and bending at the hips is still impossible. Suit wearers continue to be frustrated by the simplest things, such as the lack of visibility from their helmets, whose dimensions tend to be dictated by the neck rings – whose dimensions in turn are limited by the need to keep the shoulder joints free of obstructions.

Gloves are among the most uncomfortable components. They are too stiff to handle delicate tools. Sensitive fingertip control has to be sacrificed, because this is exactly where a suit is most in danger of puncturing as a result of wear and tear. Astronaut Kathy Thornton (a veteran of the famous Hubble Space Telescope repair mission of December 1993 that returned the stricken instrument to working order) says that working in a space suit is “like trying to adjust the carburettor on your truck while wearing baseball mittens. On TV it looks a breeze, but it’s truly exhausting.”

Astronauts peeling off their suits after a session outside ISS sometimes reach for plasters to heal bruised or bleeding fingers. Unsurprisingly, the glove material around the fingers tends to be the thinnest component of a spacesuit’s cladding. With sunrise and sunset alternating every 90 minutes as the ISS speeds around the earth, a long spacewalk repeatedly exposes astronauts to extreme cold. In February 1995, Michael Foale and Bernard Harris had to be called back inside prematurely in case they lost their fingers to frostbite.

Astronauts can overheat drastically in sealed space suits. Next to their skin, they wear a garment similar to long johns, threaded with thin hollow tubing. Water from the cooling system circulates through the tubes, absorbing excess body heat. Then the warmed water is passed into a small radiator in the life support system. Heat is dumped into space via sublimation (evaporation from ice).

It’s not a good thing if water gets loose inside the suit. On 16 July 2013, whilst working outside the International Space Station (ISS), spacewalking Italian astronaut Luca Parmitano almost had the unpleasant distinction of becoming the first man to drown in orbit when his cooling garment sprang a leak. Instead of pooling at his feet as it would have done under normal gravity, the water migrated everywhere, clinging to his face, obscuring his vision, and getting into his nostrils and mouth. As ISS swept around the night side of Earth, Parmitano was in the dark, and had to feel his way around the station’s exterior, one handhold at a time, until he could find the airlock and get back on board.

Scares are rare. From the earliest days of space flight to the modern ISS era, nearly 800 individual spacewalks have been undertaken (teams usually venture out in pairs). Taking moonwalks into account, humans have spent over 4000 hours outside the shelter of their spacecraft, and the safety record for both Russian and American spacesuits has been remarkably good. Even so, a complete overhaul of this technology will be needed for future missions into deep space.

Under pressure

Astronauts aboard early Nasa spacecraft breathed oxygen, because the ‘two-gas’ system required to emulate the oxygen-nitrogen mix of normal air would have been too complex to incorporate into the tiny vehicles. The ISS crew breathes a safer mix of nitrogen and oxygen, pressurised to 101kPa, equivalent to the Earth’s atmosphere at sea level. The downside is that no current spacesuit can withstand an internal pressure of one atmosphere without becoming rigid when exposed to the vacuum of space. Therefore, the operating pressure of the suits used outside the station is only 30kPa, with the wearer breathing just oxygen.

Astronauts preparing for space walks ‘camp’ overnight in the Equipment Lock, a sealable antechamber to the main ISS airlock. They breathe pure oxygen while the pressure around them is slowly reduced to the spacesuit’s level. This dull but vital procedure purges nitrogen from their bloodstreams and protects them against ‘the bends’. As divers know, atmospheric gases dissolved in the blood (and especially nitrogen, which is not absorbed into blood cells or bodily tissues) can form lethal bubbles when decompressed.

Suits for solid ground

The ISS has the equipment necessary to support controlled decompression. Future human missions to the moon or Mars, using smaller spacecraft, may have to dispense with it. Suits and ships alike will have to operate at the same pressure. The problem of ‘ballooning’ will be overcome by a suit design that, at first glance, seems a retrograde development.

Nasa’s latest prototype, known as the Z-suit, looks like an armoured robot from 1950s science fiction. Recent publicity photos show an astronaut wearing a white Z-suit uncannily like Buzz Lightyear’s, but the outer fabric is a superficial layer of micrometeorite protection. Inside, there’s a shell of hard composites tough enough to withstand contact with jagged rocks and abrasive surface dust on the moon and Mars.

Whenever an astronaut on a planetary mission climbs out of a suit, there will be a danger of inhaling potentially toxic dust particles from outside the lander or habitat. The simple solution is to never expose astronauts to the suit’s mucky exterior. Actually, this is easier than it sounds. The rear of the Z-suit features an airlock. When not in use, the entire thing is stored on the outside of a rover, docked to a ‘suit portal’. Essentially a Z-suit is like a miniature spacecraft in its own right. Astronauts can swap at will between the suit and the airlock areas of a habitat or rover without waiting for the pressures to equalise. Ballooning is eliminated by pushing the rigidity of the suit to the logical extreme, until its fabric has no flexibility at all, except in the gloves and at the limb joints.

Those joints are among the cleverest elements. The Z-suit looks clumsy, but it’s incredibly easy to move around in. The shoulders, elbows, hips and knees are articulated by means of rolling convolute joints built from polished titanium and stainless steel. The similarly articulated waist joints have sufficient freedom of movement to allow the wearer to touch the ground with their fingers: a feat that no other space suit has ever managed.

Designing for movement

At Nasa’s Johnson Space Center in Texas, Amy Ross is lead developer for the Z-series. “Spacesuits have traditionally been determined around a set of basic dimensions, such as chest and waist measurements, arm length, and so on,” she explains. “This tells us very little about how an actual person wears one.” Body measurements are usually taken with the subject standing upright with their shoulders back, “but nobody really stands like that, except a solider on parade.”

As a consequence of flawed fitting, says Ross, “a wearer moves inside a typical space suit about 30 per cent more than the suit moves. That’s exhausting. To put it in a nutshell, most spacesuits don’t fit very well.”

Dozens of volunteers, either astronauts, or people with similar builds and professions, were scanned in 3D while simulating the kinds of motion that a working planetary explorer might make. Ross has created a more accurate composite of ‘the typical astronaut.’ The Z-suit was designed around this naturalistic template.

No one in Ross’s team is seeking plaudits from the fashion industry. What they’re trying to build is a spacesuit that will enable humans to leave Earth orbit and venture, at last, into the depths of the solar system. Now all they need is a ship to carry them.

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