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Dr. Hawking's body double

Zero Gravity Corp.
Ted Straight, the 14-year-old stand-in for Stephen Hawking, is lifted into a
weightless float by Zero Gravity Corp.'s Peter Diamandis (left) and Byron
Lichtenberg (hands at right) during a practice flight in Florida today. Click on the picture to watch a video of Straight's zero-G encounter, narrated by Diamandis.


How many 14-year-old kids can say they've taken the place of Stephen Hawking, one of the world's smartest guys? Ted Straight can say that as of today. The 105-pound, 5-foot-5 eighth-grader served as the stunt double for the 105-pound, 5-foot-5 physicist during a practice run for Hawking's first-ever weightless experience. "I think it's really cool," Straight told me.

Hawking, the world-famous physicist who is known for his theories on black holes and the origins of the universe, is in Florida this week to go on a zero-gravity flight, which he sees as an initial step toward his dream of flying in space.

On Thursday, the 65-year-old genius, who has a degenerative nerve disease known as amyotrophic lateral sclerosis, will roll his high-tech wheelchair out to a converted Boeing 727, take off from Kennedy Space Center's shuttle landing strip and be guided into position for what's basically a roller-coaster ride in the sky. During the top half of the plane's parabolic ups and downs, Hawking and his fellow fliers will be able to float in the air for about 15 to 20 seconds at a time.

It will the first time in decades that Hawking has been in the air free of his wheelchair - and that poses lots of logistical challenges: Exactly how will he get onto the plane, into his seat, then into a preparatory prone position atop a specially designed mattress? What will it feel like when his coaches and a nurse gently lift him up for a zero-G float? Where should his assistants, doctors and camera operators be placed? How close should the other fliers get?

You don't want to be figuring all that out in real time, and that's where Ted Straight played his role. During today's practice run, the able-bodied Straight climbed into a wheelchair and traced every step of the process - including his first-ever zero-G experience. Meanwhile, Hawking was back at his hotel in Orlando, getting ready for his turn on Thursday.

Straight, an eighth-grader at Stone Middle School in Melbourne, Fla., said he was recommended for today's duties by his science teacher, Karen Regan. "She thought I was a perfect match for all the criteria," Straight told me.

That includes the height and weight specifications, said Peter Diamandis, the founder of Zero Gravity Corp. and the man who invited Hawking to take a free flight. But Straight said there were other factors, such as the ability to work well with adults. Heck, with his tousled brownish-blondish hair, Straight even looks the way I imagine Hawking looking when he was 14 years old. 

Zero Gravity Corp.'s usual routine will be tweaked for Hawking's historic flight. Each of Thursday's zero-G parabolas will run for a slightly shorter time, and the hyper-G hangover - the flip side of zero-G that is the most taxing part of the flight - will be less grueling (1.5 G's as opposed to the usual 1.8 G's).

Before every parabola, Hawking's medical team will check to make sure he's OK - and if he isn't good to go for whatever reason, the plane will return to Kennedy Space Center's strip, and everyone will call it a day.

Some folks are paying as much as $75,100 a couple to fly along with Hawking this week, with the proceeds going to charities that serve people with disabilities. So the fact that they went along on today's practice run in zero gravity ensured that they'll be getting a good ride for their money, even if it turns out that Hawking isn't up for his own dose of ups-and-downs. (By the way, Hawking told me today with a simple "yes" that he would be taking medication to counter motion sickness.)

Straight, meanwhile, is content with today's brush with fame. He had his first zero-gravity fling - and he also got to meet Hawking in person, which was an experience equally as cool.

So what will he be doing on Thursday, Hawking's big day? "Going to school," the eighth-grader said.

Update for 11:50 p.m. ET: After today's practice run, Straight said he didn't feel any motion sickness at all: "No, actually it was really fun," he told me. You can watch a video of Straight in zero-G.

Diamandis said the biggest challenge for Straight may have been to lie still and let the coaches lift him up, as they will do for Hawking on Thursday.

"We learned in particular how to control his body ... how to position him," Diamandis said.

The doctors also practiced monitoring Straight's vital signs after each parabola - measuring his blood pressure with a pneumatic cuff around the arm, analyzing his heart readings with an EKG monitor wired to his chest, and checking his blood oxygen levels with a probe placed on his earlobe. The medical team's prognosis? "They feel very confident about tomorrow's flight," Diamandis said. So now it's time for the real thing.

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 Space News section, on NBC's "Nightly News" and the TODAY show.