Quadriplegic physicist Stephen Hawking is ready to go where no person with his kind of disability has gone before: into weightlessness, aboard a specially outfitted airplane flying from the runway where space shuttles land.
On the eve of Thursday's scheduled flight, Hawking told NBC News that he saw such adventures as "a first step toward space travel" — not only for him personally, but also for the public at large.
"I think the human race doesn't have a future if it doesn't go into space. I therefore want to encourage public interest in space," he said in his computer-generated voice, responding to questions submitted in advance.
Hawking has become renowned for his theories on black holes, the workings of gravity, the origins of the universe and other mysteries explained in his best-selling book "A Brief History of Time." The 65-year-old Cambridge cosmologist also has coped for decades with a degenerative nerve disease called amyotrophic lateral sclerosis, or ALS. He has lost virtually all voluntary movement, except for his facial muscles, and can communicate only through a gesture-controlled computer system.
Significant step toward space
Hawking hopes a successful zero-gravity encounter on Thursday will represent a significant step toward his dream of flying in outer space as early as 2009, aboard a suborbital rocket plane now being built for British billionaire Richard Branson's Virgin Galactic venture. Virgin Galactic's spaceship is a scaled-up version of SpaceShipOne, which won the $10 million Ansari X Prize in 2004 as the first privately developed craft to take humans to outer space.
"I have wanted to fly into space for many years but never imagined it would really be feasible," Hawking explained. "After the X Prize was won, and private spaceflight became possible, I started thinking about it more seriously."
During the past year, Hawking has been more vocal about his outer-space dream, telling one interviewer that it was his "next goal." In response, Florida-based Zero Gravity Corp. invited him to take a flight on "G-Force One," a Boeing 727 jet that simulates the weightless feeling of space travel by flying a series of roller-coaster parabolas at an altitude of roughly30,000 feet.
Every one of the five millionaires who have flown to the international space station has been on such flights — as have celebrities ranging from moonwalker Buzz Aldrin to lifestyle guru Martha Stewart. The going rate for Zero Gravity's commercial service is $3,500 per person, but the company waived the cost for Hawking and his team.
"When Zero Gravity Corp. offered me this flight, I accepted immediately," Hawking told NBC.
Pioneer for people with disabilities
Hawking will be Zero Gravity's first wheelchair-using passenger, according to the company's chief executive officer, Peter Diamandis. The Federal Aviation Administration only recently approved procedures for providing weightless flights to customers with such disabilities, he explained.
"You're our first pioneer in so many ways," Diamandis told Hawking during a preflight briefing at an Orlando hotel on Wednesday.
Takeoff is scheduled for Thursday afternoon from the Shuttle Landing Facility at NASA's Kennedy Space Center, which has been used for previous Zero Gravity flights as well as shuttle landings.
Hawking told NBC that he expected weightlessness to be a "wonderful" experience. "It has been many years since I've been free of my wheelchair," he said.
However, Thursday's adventure carries medical risks for someone as frail as Hawking.
The risks and the resolutions
The main medical concern has to do with how Hawking's breathing will be affected by the periods of heavier-than-normal gravity that must follow every zero-gravity float, Diamandis told reporters.
There could be an effect on Hawking's heart, and he may experience the motion sickness sometimes associated with weightless flights. Because no person in his condition has flown on a weightless flight before, Hawking's caregivers are not completely sure how serious the effects could get. But those uncertainties will have to be resolved if Hawking ever hopes to take a suborbital spaceflight, which involves greater stresses than weightless airplane flights.
To ensure Hawking's safety, several extraordinary measures are being taken:
- The doses of zero-gravity on Thursday won't last as long as they usually do — about 15 to 20 seconds as opposed to 25 to 30 seconds. That means the pullout from weightlessness will be milder as well — 1.5 times as strong as normal gravity rather than 1.8.
- Hawking will be carried from his seat on the plane to an area marked off especially for him, where he will be laid down on a soft head cushion. Two coaches and a nurse will raise Hawking up at the start of each period of weightlessness, and gently bring him down at the end.
- After each float, medical team will check Hawking's blood pressure, cardiac rate and blood oxygen level. Hawking will raise his eyebrows if he feels up to another parabolic rise to weightlessness. If he grimaces, that means he's had enough.
- Diamandis has said that he would count the flight as a success if Hawking flies just one parabola — even though Hawking himself has indicated he'd like to do more. Once Hawking is finished, the plane would return to the landing strip.
- To rehearse the procedures for Thursday's flight, Zero Gravity conducted a practice run on Wednesday, with 14-year-old student Ted Straight standing in for Hawking. Diamandis said the "full-up dress rehearsal" was a success.
Hawking and his team won't be the only ones on the flight: More than two dozen people are on the passenger list, including video game designer Richard Garriott, the son of Skylab astronaut Owen Garriott.
Some of the passengers are on board as the result of a money-raising campaign for the X Prize Foundation, which Diamandis heads, and for several charities serving people with disabilities. Diamandis said about $150,000 had been raised for the charities by selling seats on Wednesday's practice run as well as Thursday's flight.
Additional support was provided by Space Florida, a state agency that promotes Florida's commercial space industry and space-related educational activities; and by the retailer Sharper Image.
Boost for commercial spaceflight
Hawking said he hoped his flight would provide a boost for commercial spaceflight, in line with his oft-expressed belief that humanity's future depended on moving beyond Earth.
"I think that getting a portion of the human race permanently off the planet is imperative for our future as a species. It will be difficult to do this with the slow, expensive and risk-averse nature of government space programs," Hawking told NBC, working in a veiled reference to NASA. "We need to engage the entrepreneurial engine that has reduced the cost of everything from airline tickets to personal computers."
He said tourism could represent a future mass market for space-oriented services, "and zero-gravity flights are the first, most affordable step in that direction."
"I am hopeful that if we can engage this mass market, the cost of spaceflight will drop," Hawking said, "and we will be able to gain access to the resources of space, and also spread humanity beyond just the earth."
MSNBC.com science editor Alan Boyle is in Florida with a team from NBC News to cover Hawking's flight on Thursday. Look for updates throughout the day on Cosmic Log as well as full reports in MSNBC.com's section, on NBC's and the show.