By Kim Griggs in Wellington, New Zealand

In a little over a week, two pilots, one of them US adventurer Steve Fossett, will attempt to glide into the stratosphere and the record books.

If we do [encounter turbulence], the airplane is strong enough to hold it and to handle it

Ed Teets, Perlan's chief scientist

Far above the tiny town of Omarama in the South Island of New Zealand, Fossett and former Nasa test pilot Einar Endevoldson will be aiming to reach 62,000 feet (18,900 m), a height that would smash the current world altitude record for a sailplane of 49,009 feet set in 1986.

The flight is just the first part of Fossett and Endevoldson's ambitious Perlan Project. In the second part, the team wants to try to fly as high as 100,000 feet (30,500 m) - more than 30% of the way into space.

"Most of the atmosphere we live in is in the troposphere, so when you get into the stratosphere you're through most of it," said Elizabeth Carter, the Perlan Project's chief meteorologist.

Southern route

In the first phase of the project, a combination of the polar vortex that swirls past the gliding capital of Omarama, mountain waves and specially built pressure suits will give the pilots the ability to soar into the stratosphere, the Perlan team believes.

"The pressure suit system is the key. Right now the physiological ramifications can be quite significant," said Ed Teets Jr, the project's chief scientist and a Nasa aerospace engineer and meteorologist. "You get to those [high altitudes], the nitrogen inside your body will start to boil."

Once the sailplane tops 40,000 feet (12,200 m), the pilots' pressure suits will inflate. Foot warmers will ward off the frostbite that the outside temperature of minus 50 Celsius would inflict.

Also helping them soar into the stratosphere will be westerly winds that sweep across New Zealand's Southern Alps, creating the mountain waves that the gliders ride. And it is the Antarctic polar vortex, rather than its northern equivalent, that appears conducive for the record attempt. "It's stronger, it lasts longer and it's more regular," said Dr Carter.

Tough plane

This combination of the waves and the vortex should, the project team hope, enable the glider to be able to pierce the tropopause, a band of air that separates the troposphere from the stratosphere, and which often extinguishes mountain waves.

Steve Fossett: From one adventure to the next

"When you get the winds hitting the mountains near perpendicular - along with this polar vortex which gives you increasing wind speeds with altitude - that allows these waves to penetrate on up through," said Dr Carter.

Flying into the unknown is not without its dangers. Riding a true mountain wave is smooth, but severe turbulence could occur.

"It's going to be hit and miss." said Dr Teets. "We don't know for sure that there will be turbulence. We just don't. But if we do [encounter turbulence], the airplane is strong enough to hold it and to handle it."

Mars experience

If the plane does become uncontrollable, the pilots have the option of using a drogue chute as a stabilizer.

"They'll use that stabilisation until they either get control of the aircraft back or they get to a low enough altitude that they can jump out," said Dr Teets.

The vortex lasts longer than its northern counterpart

The plane will be the main limitation for the Omarama flights, as it has an upper reach of 62,000 feet. In the second part of the project, a specially designed pressurized sailplane would be built to soar to 100,000 feet.

That altitude would mimic flying in the Mars atmosphere and could answer crucial questions for any future Mars voyagers. "What can we expect? What is the Mars atmosphere like? Is it turbulent? Is it smooth? Is it windy?" asked Dr Teets.

The 60,000-foot flights will bring important atmospheric data. "To characterize a wave, that's something that's never truly been done," said Dr Teets.

Each attempt on the world record is expected to last between four and six hours. The team in Omarama starts preparatory flights this week and will begin record attempt flights around 21 July.