The author of the bestselling A Brief History of Time, theoretical physicist Stephen Hawking, expects his brief experience of weightlessness on Thursday aboard an airplane offering "zero-gravity" flights will be "bliss."

British physicist Stephen Hawking is looking forward to his brief experience of weightlessness Thursday.
(Markus Schreiber/Associated Press)

Hawking, who uses a wheelchair and is almost completely paralyzed by amyotrophic lateral sclerosis, or Lou Gehrig's disease, will experience the weightless flight courtesy of Zero Gravity Corporation, a Florida-based space tourism and entertainment company.

"For someone like me whose muscles don't work very well, it will be bliss to be weightless," Hawking said Tuesday.

Zero Gravity Corporation uses a modified Boeing 727 jet to deliver the feeling of weightlessness to customers. The plane climbs to about 9,000 metres at a sharp angle and then plunges 2,700 metres, repeatedly. Inside the descending aircraft, passengers experience 25-second snippets of zero gravity.

The flight will take off and return to a landing strip at the Kennedy Space Center in Cape Canaveral, Fla.

The plane normally does 10 to 15 plunges per flight, but Hawking's will make a single plunge. Doctors and nurses accompanying the astrophysicist will monitor his condition to ensure he is comfortable before taking additional plunges.

"We consider … having him weightless for 25 seconds is a successful mission," said Peter Diamandis, the chairman and CEO of Zero Gravity. "If we do more than one, fantastic."

Zero Gravity will pick up the bill, which normally is $3,750 US. The company also plans to have two seats on the flight auctioned off to provide money to charities.

The company began offering the flights in 2004.

"I hope it goes OK," Hawking said. "But there's always a chance things can go wrong."

Last year, Hawking publicly spoke of his desire to go into space and made an appeal to Sir Richard Branson, whose company, Virgin Galactic, is building a suborbital spaceship that could be flying passengers beyond Earth's atmosphere by 2009.

Branson has decided he will personally finance Hawking's ticket into space — a flight that would normally cost $200,000 US.

With files from the Canadian Press