TWO balloon pilots have touched down at Boscombe Down airfield as part of crucial safety tests before attempting to break the world balloon altitude record later this summer.

Andy Elson (49), of Wells, and Colin Prescot (52), of Stockbridge, are sponsored by science and technology research organisation QinetiQ and are part of a British attempt to smash the record held by the Americans for 40 years.

QinetiQ 1, as the team is called, hopes to fly a giant helium balloon to the edge of space, an amazing 25 miles from earth, on a journey where temperatures could fluctuate between -56C and -20C.

To ensure the pilots and their equipment will be able to cope with such extreme temperatures, Andy and Colin were at Boscombe Down last week to take part in a full operations check in QinetiQ's state-of-the-art environment chamber.

Wearing specially designed Russian spacesuits and wrapped in a layer of insulation, the pilots were kept in the chamber at -50C.

They were also exposed to a bank of strong lights to mimic intermittent exposure to the sun.

After nearly three hours strapped into their flight platform, Andy and Colin emerged with nothing but praise for their spacesuits and life-support systems.

"It all went fine," said Andy, who has designed most of the round-the-world balloons of recent years.

"The cold wasn't really a problem, except on our fingers when we took the gloves off to operate the controls.

"We also had a slight problem with condensation on our visors.

"Before today, I would have said that our biggest worry was actually the heat at high altitude - we were worried we would bake.

"But today we tested our solar shields and, although they look incredibly flimsy, they work very well.

"Our biggest worry, which was overheating, has now been removed."

Nevertheless, Andy and Colin will still face a number of challenges during their 11-hour record-breaking attempt.

"It's going to be hard work but I'm really looking forward to it," said Colin, who made history in 1991 when he manned the first British balloon flight through a whole night.

"The view from the top will be amazing.

"It's going to be a great adventure, the greatest adventure I've ever been on."

QinetiQ 1 hopes to launch the balloon, which will be as tall as the Empire State Building when fully inflated, between now and September.

If the record attempt is successful, Colin and Andy will not only break the world manned altitude record, but will also become the first Britons to pilot a manned space mission.