SCIENCE TRIBUNE Thursday, June 6, 2002, Chandigarh, India

Wardrobe for space travel
Amar Chandel
hink of an astronaut and chances are you will visualise him complete with a bulky spacesuit and a tinted-glass visor. If the apparel has come to be treated as an integral part of his macho persona, it is because space journey is just not possible a space suit. What appears to be an unwieldy quilted dress from outside is actually a marvel of cutting-edge technology. How sophisticated and complex this suit is can be gauged from the fact that each costs upwards of $ 12 million (Rs 60 crore).




Wardrobe for space travel
Amar Chandel

Think of an astronaut and chances are you will visualise him complete with a bulky spacesuit and a tinted-glass visor. If the apparel has come to be treated as an integral part of his macho persona, it is because space journey is just not possible a space suit.

What appears to be an unwieldy quilted dress from outside is actually a marvel of cutting-edge technology. How sophisticated and complex this suit is can be gauged from the fact that each costs upwards of $ 12 million (Rs 60 crore). That is why it is no longer custom-fitted as per the measurements of the person selected to go on a space mission. Instead, it is modular in design, with many interchangeable parts. The upper torso, lower torso, arms and gloves are manufactured in different sizes and can be assembled to fit men and women astronauts. This way, the suit can be reused, for nearly eight years, of course after elaborate cleaning and drying after every flight use.

If the price tag staggers you, just think of the environment in which an astronaut has to work. There is no atmospheric pressure and no oxygen to sustain life out there. The spacesuit is his only shield against the hostile elements that he encounters. A person not hiding inside this cocoon in space will have his bodily fluids "boiling" and then freezing within seconds. That, in other words, means an almost instantaneous death.

Without the earth’s atmosphere to filter the sunlight, the side of the suit facing the sun can simmer at a temperature of 120 degrees C while the other side exposed to the darkness of deep space could be at minus 100 degrees. That is far worse than half of you being in the Sahara desert at noon in the summer and the other half being on Mt Everest at midnight in winter — simultaneously.

That is talking only about the temperature extreme. There are several other equally severe extremes that an astronaut has to encounter. He has to carry his own earth-like environment with him and it is the spacesuit that provides it by supplying oxygen and maintaining a pressure around the body to keep body fluids in liquid state.

Essentially, a spacesuit is an inflated balloon that is restricted by some rubberised fabric, in this case Neoprene-coated fibre. The restriction placed on the outside supplies air pressure on the inside. The standard environment in the suit is just 0.29 atmosphere of pure oxygen. The pressure is deliberately reduced for two reasons. One, it considerably improves freedom of movement for the wearer. And two, it decreases the overall stress on the suit.

Hundred per cent oxygen (instead of the normal air comprising 78 per cent nitrogen, 21 per cent oxygen and 1 per cent other gases) is provided either through a life support system in his backpack or through umbilical cords running from the spacecraft to the spacesuit. This life-support system re-circulates the user’s exhalations, removing carbon dioxide with the help of lithium hydroxide canisters and adding oxygen as needed.

But due to the decreased pressure, an astronaut has to spend several hours breathing pure oxygen before leaving the space shuttle to perform tasks in space. This procedure is mandatory to remove nitrogen dissolved in body fluids and thereby to prevent its release as gas bubbles when pressure is reduced. If this precaution is not taken, the astronauts can develop, like deep-sea divers, severe cramps called "the bends".

Suitable communication arrangements are also incorporated into the space suit. The "snoopy cap", or the communications carrier assembly, has headphones and microphones for two-way communications and caution-and-warning notes, plus a biomedical instrumentation subsystem to monitor the astronaut’s vital signs such as respiration rate, heart rate, temperature etc.

Things have changed a lot from the early days of space exploration when an astronaut had to wear a spacesuit, like a jet pilot, throughout the duration of his journey.

Astronauts of the space shuttle era have an elaborate wardrobe and what they wear depends on the job they are doing. During ascent and entry, each crewmember wears special equipment consisting of a partial pressure suit, a parachute harness assembly and a parachute pack. During orbit, they work in shirtsleeve comfort inside the shuttle. But to work in the open cargo bay of the shuttle or in space, they wear the extravehicular mobility unit (EMU) spacesuit, which is more durable and flexible than previous spacesuits. It comprises the spacesuit assembly, the primary life support system (PLSS), the display and control module and several other crew items designed for spacewalks and emergency life support. In short, EMU is a mini-spaceship in itself.

The suit protects him from lethal solar ultraviolet and infrared radiations and also the constant bombardment of micrometeoroids. That is why it comprises 13 layers of material, including an inner cooling garment (two layers), pressure garment two layers), thermal micrometeoroid garment (eight layers) and outer white cover to reflect sunlight (one layer). All these layers are cemented together.

Despite all these preparations, the spacesuit does not offer much protection from a solar flare. That is why spacewalks are planned during periods of low solar activity.

Being padded so heavily, the astronaut’s body generates a lot of heat during active work periods. It has to be properly dissipated if he has to function with some degree of comfort. For that the spacesuit has a liquid cooling and ventilation garment, a one-piece mesh suit made of spandex, which has water-cooling tubes running through it. Cool water circulating through this network of spaghetti-like tubes transfers metabolic heat from the body to the backpack and from there to space.

Above all, the astronaut has to be able to move over and bend adequately. That is easier said that done in such a clumsy apparel. Just try holding something while wearing a heavily padded pair of gloves and you will get a fair idea of the rigors of adjusting sensitive instruments up there. The spacesuits are equipped with special joints or tapers in the fabric to help the wearers bend their hands, arms, legs, knees and ankles.

A spacewalk can last as many as seven hours. Since it is not feasible for an astronaut to be brought back into the space station whenever he has to relieve himself, the spacesuit also has to double up as a portable toilet. He wears special types of diapers to collect urine and faeces which are changed only when he completes his mission.

Similarly, the spacesuit has an in-suit drinking bag, which is a plastic pouch containing 1.9 litres of water, and has a small tube, a straw, that is positioned next to the astronaut’s mouth. There is also a slot in the helmet for a rice-paper covered fruit and cereal bar that the astronaut can eat if he or she gets hungry during the spacewalk.

The bar is designed in such a way that the astronaut can take a bite and pull the remainder up. The whole bar must be eaten at once lest crumbs start floating within the helmet. It is another matter that most astronauts prefer to eat prior to the spacewalk and not use this bar.

The shoes of an astronaut are also equally complex. The boot inner layers are made from Teflon-coated glass-fibre cloth followed by 25 alternating layers of Kapton film and glass-fibre cloth to form an efficient, lightweight thermal insulation.

If astronauts have to deploy, service, repair or retrieve satellite payloads, they latch on a manned manoeuvering unit (MMU), a one-man, nitrogen-propelled backpack, to their EMU. The maximum total weight of the largest size spacesuit assembly, including the liquid cooling and ventilation garment, urine collection device, helmet and visor assembly, communications carrier assembly, in-suit drink bag and biomedical instrumentation subsystem, is about 140 kg. Thank God it does not have to be worn on earth. In space it weighs only a fraction.

There is a complicated drill involved in wearing the suit. This includes a detailed check list which has more than 25 items.

The EMUs are built under the supervision of prime contractor Hamilton Sundstrand with contributions from 52 other companies. Cut and sewn to a tolerance of one-sixteenth of an inch, one needle hole in the wrong place means back to the start of any one of the layers.

Many changes have come about in spacesuits over the decades. The initial suits were adopted from the pressurized flight suits worn by high altitude jet pilots. The first space suit was designed and developed during 1959 for Project Mercury and was a compromise between flexibility and adaptability. It had the design of the early pressurised flight suits, but had added layers of aluminised Mylar over the neoprene rubber. Living and moving in this aluminum-coated nylon and rubber garment was like trying to adapt to life within a car tyre.

Improvements have been made since then constantly. For future space missions to Mars, NASA is developing "hard suits" that are more flexible, more durable, lighter-weight and easier to don than the current spacesuits.




Clues :


1. The system of communication among ships in sea by signalling with hand-held flags.

8. Positive electrode by which electric current enters electrolyte.

9. These earths are oxides of lanthanide elements.

11. A type of rubble masonry.

13. Post graduation institute.(abbr.)

14. A computer language used mainly for military purposes.

16. Human embryo when more than 8 weeks old.

18. A programme launched by Health Department to immunise 85% children against six diseases of childhood.(abbr.)

19. ……..berg, huge floating mass of ice.

21. Pet measure used by doctors to prescribe liquid medicine doses.

23. A diagram named after two scientists and showing absolute magnitude of stars.

24. Symbol for Iron.

25. A computer term telling that the tape has ended.

26. A useful command available in computers.

27. ………dynamics, branch of physics dealing with study of rotating bodies.


1. Fastest running fish, speed 110 km/hr.

2. A warm ocean current responsible for erratic behaviour of monsoons.(abbr.)

3. International, basic radio code.

4. Abbr. for a ‘drug addiction prevention treatment’ done by a famous hospital.

5. Flightless sea fowl of southern hemisphere.

6. ……graphy, physical geography of mountains.

7. This effect tells the change of frequency of light by a vibrating substance.

10. Lose moisture as vapour.

12. Layer of cartilage between vertebrae.

15. Herb supposed to have healing power.

17. Large bird preying on inland fish.

20. A granular mineral substance consisting of corrundum and magnetite.

22. …..cycle, an idealised reversible cycle for maximum efficiency in a four stroke engine.

24. British system of units.

Solution to last week’s Crossword: