With the age of suborbital tourism beckoning, hundreds of wealthy people have signed up to take rides to the edge of space, a trip that will end almost as soon as it begins, but should confer serious bragging rights when the talk turns to summer vacations.
Of course, if just experiencing weightlessness is your goal, you can already do it for far less than Virgin Galactic’s $200,000 ticket price—but only in 30-second bursts. Inside a modified Boeing 727 operated by Zero Gravity Corporation, adventure tourists can spend a few thousand dollars to get a taste of weightlessness and sample lunar and Martian gravity as the airplane flies repeated roller-coaster-like parabolas. During their half-minutes of reduced gravity they can float, tumble, even get married. But there’s no view of Earth, and it’s more like an amusement park ride than a rocket launch.
The suborbital spaceships now on the drawing boards will carry tourists to the edge of space (traditionally set at 100 kilometers, or 62 miles altitude), but not so high or fast that they go into orbit. Virgin Galactic’s SpaceShipTwo will provide up to six minutes of weightlessness, while Armadillo Aerospace, XCOR, and various other companies will make you feel weightless for about three minutes.
Since XCOR’s Lynx spacecraft holds just a pilot and one passenger in a tiny side-by-side cockpit, the company has decided that passengers will remain strapped in for the whole trip—just as Alan Shepard and Gus Grissom did during their 15-minute suborbital missions to test out NASA’s new Mercury spacecraft in 1961.
Other companies have released animations showing passengers unstrapping from their couches, floating around in weightlessness, then returning to their couches before atmospheric reentry.
XCOR thinks that’s a bad idea.
“Unstrapping and re-strapping in such a short time frame would be a risky endeavor,” says the company’s communications representative, Mike Masse. He believes that passengers will be so engrossed by the spectacular view that they won’t mind being confined to their couches.
Virgin Galactic sees less of a problem with its SpaceShipTwo. “Our experience will have significantly slower transitions between zero-G and G than [do the parabolic airplane flights],” says James Vanderploeg, the company’s chief medical officer. “We're confident that our customers will be both ready and eager to get up out of their seats once they reach space.”
Neil Milburn, vice president of program management at Armadillo Aerospace, agrees that the transition should be comparable to parabolic flight. “As soon as there is a modest amount of G-force, one naturally ‘sinks’ back to the bottom.”
But two astronauts who are also physicians say the airplane and suborbital experiences will be markedly different. “G onset on the way back [from 100 km altitude] will be quite brisk, and the Gs will be in excess of six on some vehicles,” says Scott Parazynski, a veteran of five NASA spaceflights. “My guess is the last 30 to 45 seconds of the microgravity phase will have to be allocated to seat ingress.”