At any given time, Nasa will have 12 spacesuits in circulation. Often four will be in use on a mission; the rest are kept in the Hamilton offices to be checked, repaired and altered. "People make the mistake of thinking a spacesuit is just a spacesuit. It's much more than that. It's a one- man spacecraft, an entire life-support system for the astronaut," says Charlie Porter, head of Hamilton Standard in Houston. It must meet the astronaut's every need, providing warmth, a cooling system, air to breathe, water to drink, and at the same time removing carbon dioxide and water vapour. The temperature inside the suit can be adjusted between 10C and 45C to cope with the alternating bitter cold and searing heat of outer space. The jet-pack, worn on the back, is to prevent the astronaut from drifting away like Major Tom: should he become untethered from his Shuttle, he can simply use the jet to propel himself to safety.
As well as photographing the work on the modern suits, Benali was given access to the Nasa archives at the Space Centre. He selected pictures of the many confections which have been made since 1937, when Wiley Post (pictured overleaf with his prototype) designed the first pressurised spacesuit. The Wiley Post suit was made of rubber, fastened with laces; on the head was delicately balanced a huge, cumbersome, extremely heavy metal helmet incorporating only a tiny peep-hole for vision.
Ever since then, teams of engineers have laboured to make the suits lighter, tougher, more flexible, less bulky. The Russians had overtaken the Americans by 1965, when Alexei Leonov became the first man to walk in space, but his equipment was still extremely primitive by today's standards. When Leonov stepped out into space, his suit ballooned with oxygen so that until he lowered its pressure he was unable to fit back in the capsule.
For every advance that the Americans made, a new problem was discovered. The first US astronauts to go on an EVA (Extra-Vehicular Activity: in lay terms, a space walk) found that their suits lacked an adequate ventilation system, so that when it was warm a moist heat would rise, causing their visors to mist up. The heating system, too, was ineffectual (special heating tubes in which the astronauts could warm up after a chilly excursion were introduced) and the astronaut's gloves were clumsy and inflexible, and did little to keep out the cold.
These early suits and prototypes are spectacular: unwieldy, restrictive and completely unconvincing. Some appear to be straight from Seventies television sci-fi. The more sinister- looking versions, such as the 1965 prototype for the Apollo mission, were discarded in favour of the less threatening Michelin-man design, which is similar to the design of the modern suits. Sweet in their inelegance, the suits look as though they could have been designed to appeal to any aliens the spacemen should chance to encounter.
By the time Neil Armstrong made his lunar landing almost exactly 30 years ago, the engineers had greatly improved the suits' mobility and had equipped them with a liquid cooling device. Best of all, a small rubber protuberance had been attached to the inside of Armstrong's helmet, specifically to enable him to scratch his nose.
It is a strange fact that today's astronaut wears a nappy beneath his suit. Compared to the old system, consisting of various plastic tubes and vacuum bags, this is a lesser indignity: on a number of occasions in former years the receptacle would break, allowing urine to free-float unpleasantly within the suit, soaking its occupant. Legend has it that, in one giant leak for mankind, Buzz Aldrin once came to grief in just such a way.
Early functioning suits like those used in the early Seventies cost about $5,000 (pounds 3,100) to make. By contrast, today's fashionable astronaut will be wearing an outfit that comes in at $10.5m (pounds 6.5m), despite its being from the ready-to-wear range (the suits are altered to fit individual astronauts). Rather than replace the entire suit when it starts to show wear, gradual alterations are made between missions, and components such as gloves or boots can be substituted. Further innovations are always being made: most recently, to meet the challenge presented by the construction of the Alpha International Space Station. The astronauts who are building Alpha will be handling metal which, when the temperature drops suddenly to -87C, will become intensely cold. Many an astronaut has had to abandon an EVA because of freezing fingers. This is why new gloves (costing $100,000 (pounds 62,500), a pair) have been designed. They are more malleable (working on construction in space has been likened in the past to performing "surgery with boxing gloves") and have been installed with a separate battery-powered heating system. The gloves were put to the test this May, when the first stage of construction began.
The gigantic enterprise will require at least 1,700 hours of space work, more than the combined total of all time spent on EVAs to date. Until now, missions in space have lasted on average only a couple of hours. With the construction of Alpha now under way, astronauts will be required to spend eight-hour stretches on the outside, so the suit's drinking water capacity has had to be increased: 1.5 litres instead of the previous half- litre. The water supply is contained in bags which are strapped to the astronaut's thighs. A tube leads up to his helmet, and he can drink by turning his head and sucking from a nozzle. A tricky arrangement involving a high-energy food bar being attached to the inside of the helmet has been discarded, because it was found that the snack tended to miss the mouth and end up smeared all over the visor.
In the meantime, as the final touches are put to the Alpha suits, over at Hamilton Standard's design headquarters in Connecticut preparations are being made for the launch of a new collection in the year 2017. Destination: Mars.
Main picture: a Hamilton Standard space tailor works on the plexiglass torso of a spacesuit.
Right from top: a pair of space gloves nearing completion; an additional potable water container is tested in preparation for a mission to the International Space Station; the first line of defence in the spacesuit, astronaut nappies; Hamilton Standard's spacesuit depot at Nasa in Houston, Texas
Top row from left: Wiley Post models his revolutionary pressure suit, 1937; pressure suit prototype, 1951; outfit developed for the Gemini programme, 1964; spacesuit test for Apollo programme, 1965; prototype suit, 1984; prototype for the Freedom space station, 1987.
Bottom row from left: human version of primate semi-pressure suit, 1968; 1950s prototype of a warming bag for astronauts; spacesuit prototypes for men and women, 1990; astronaut Joe Engle with his children, 1970