The height of ambition

Andy Elson and Colin Prescot plan to strap themselves to a balloon and float to the edge of space. They're British, of course. Julia Stuart asks them what they think they're doing

Any day now, weather permitting, a tiny platform, measuring just 2m x 3m, will lift into the air, attached to a hot-air balloon as tall as the Empire State Building and made from material as thin as a freezer bag. Strapped to seats on the open flight deck will be two Englishmen wearing oxygen-filled, pressurised spacesuits that will prevent their blood from boiling and their lungs from collapsing as they rise 25 miles to the edge of space, passing through temperatures that could range from -70C to 100C.

If all goes according to plan, after a few hours of hanging around in the blackness, admiring the earth's curvature below and waving to the world on live TV, they will descend with as much grace as they left Earth and splash down in the Atlantic, 200 miles off the St Ives coast. Champagne corks will fly as Britain becomes the third nation to put a human in space and the pilots – Andy Elson and Colin Prescot – claim a new world altitude record for a manned balloon flight.

But today, at the project's headquarters – two warehouses on a bleak industrial estate in Glastonbury, Somerset – things are not going swimmingly. The pilots' emergency parachutes have just arrived. Prescot tries one on, only to discover that it has been incorrectly stitched and twists when fastened. "It was made in a hurry," Andy Cox, the engineering director, explains. "Yours has been test-jumped, actually."

Prescot runs Flying Pictures, the largest operator of hot-air balloons in the world, which is managing the project. He and Cox are surrounded by three equally dismayed-looking Russians from Zvezda, the spacesuit manufacturer that has designed all the suits for the Russian space programme over the past 50 years and those currently worn on the International Space Station.

The Russians, who have tailor-made suits for the two Englishmen, start inflating Prescot's, checking for leaks. "Even if your oxygen supply cuts off, it's amazing how long the suits will keep you alive. It's a very long time – 20 minutes, 25 minutes," says Prescot. He estimates that, after take-off from a ship off the St Ives coast, they will be airborne for 8-12 hours. They each have nine hours of oxygen, as well as an emergency three-hour supply.

Next to Cox, in a taped-off area behind a sign that warns: "Fragile structure. Do not move. Limited access. Use kneeling boards and gloves. If in doubt ask", is the flight platform, made of carbon fibre. "They're half-millimetre-thick skins on either side of a very thin foam floor, so we're careful about who steps on it," says Cox.

If anything goes wrong during the flight, a series of parachutes can be deployed to bring the platform down safely. "We would probably be able to bring the pilots down from the top in about 20 to 25 minutes, if we try hard. It's not actually that fast, but it's fast enough," says Cox.

Prescot and Elson are no strangers to record attempts. In 1999, they set the world endurance record for any aircraft in the Earth's atmosphere in their failed round-the-world attempt. Elson piloted the first balloon flight over Mt Everest, and Prescot holds the record for the longest balloon flight in the UK. The record they are now trying to break – an altitude of 21.5 miles – was set 41 years ago by two US Navy officers, Malcolm Ross and Vic Prather, as part of the American space programme. Tragically, Prather missed the strop on the helicopter that had come to pick them up afterwards. He fell back into the sea, his spacesuit filled with water and he drowned.

"We have had specific training in Moscow with these gentlemen to make sure that that couldn't happen," says Prescot. "There's one very simple solution, for a start – a life jacket, which Prather didn't have."

Why is he doing it? Prescot pauses. "It's the idea of going into space by slightly unconventional means and making Britain the third nation to put a man in space. The idea of two little spacemen on an open deck under the biggest balloon in history in a completely black sky with the curvature of the Earth underneath is inspirational. Altitude is the ultimate professional challenge for a balloonist."

Is he at all concerned about his safety? "The worst thing that could happen is that the spacesuits fail much more quickly than we would have thought possible and we suffer a slow and painful death... But I'm not planning to do that."

Nor is Elson. Standing in the second warehouse, he surveys his handiwork – two computer-controlled aluminium drums around which is looped the spare balloon, which, like the real thing, is made of polyethylene and is 1,250ft tall. The pilots had started negotiations to buy a balloon from an American firm, but it got cold feet, fearing that the pilots' relatives would sue if the balloon failed. There was no other option than for Elson to design and build the world's largest manned helium balloon himself. But it was not as mad an idea as it sounds. Elson has designed all the balloons used in round-the-world attempts of recent years, except for Richard Branson's. "I've been analysing all the hot-air-balloon flights that we have information about over the past 40 years, and they have roughly a 10 per cent failure rate. Which is still quite high if you're sat at the bottom of the balloon," he says. "I looked in detail at the various things that make a balloon fail and I've tried to design one that has as few of those failure points as possible."

Elson says he is more worried about making the sponsor, QinetiQ, "look silly because of some logistical cock-up" than he is about his fate. He is also concerned about the weather. The team is working closely with Reading University and the Met Office to determine the right day for the launch of the balloon, named QinetiQ1. The upper winds are unseasonably strong at present. It appears that they could not have picked a worse year in almost a decade. So far, this summer, there has been only one suitable weather slot, which they were unable to predict even 24 hours beforehand. They need 72 hours' notice to mobilise everything and fly the Russians back over. "But", says Elson, "we're still confident that by the end of September we can find a day when we will get it all together."

Elson then gives a long list of possible glitches, including: the balloon snagging during take-off, the pilots being sick during the launch (vomit would block up their exhaust vents), winds of different directions destroying the balloon, a structural weakness in the balloon becoming apparent as it expands, not reaching altitude because they've got the calculations wrong, not getting the balloon to descend quickly enough and unforgiving weather on their return.

So why is he doing it? "It's primarily an engineering challenge," he says. "It's taking something that has been ignored for the past 40 years and something that appears to be extremely dangerous and putting together a team of people whose joint engineering skills can make it successful and safe – we hope. I believe that it's important that there are people like us in the world who bounce along on the edge of reality."

For the latest news of the attempt, visit www.QinetiQ1.com/content/new.html