A Long-Awaited Taste of Outer Space

The flight took off about 2:30 p.m. here, reached 25,000 feet and then began a series of climbs at 45 degrees and dips at 30 degrees. For about 25 seconds at the peak of each hill, passengers are loosed from gravity and float. The effect is similar to the sensation felt by people on a roller coaster -- a slight sense of levitation as the ride tops a rise. While crew members said they had hoped for one to three of the zero-gravity maneuvers, they completed eight.

For Zero Gravity Corp., the company that offers the microgravity excursions to the general public for $3,500 a ride (soon to be available through Sharper Image), the flight served as a publicity vehicle.

"The only thing I can compare it to is to flying in dreams," said Peter H. Diamandis, chief executive and co-founder of Zero-G.

The danger for Hawking, his aides said, was not the sense of weightlessness but the extra gravity force at the bottom of each descent. The force could have made it more difficult for him to breathe, for example.

For safety, three physicians were aboard the flight. To allow them to monitor Hawking's condition, a probe was affixed to his earlobe to test his blood oxygen, his chest carried EKG devices, and his arm bore a blood-pressure cuff.

During the free-floating portions of the flight, Hawking was without his voice synthesizer. He was to communicate yes by raising his eyebrows and no by pulling his mouth to one side.

The fears proved unwarranted.

After one zero-gravity ride, crew members asked if he wanted to go again. Hawking dramatically stretched his eyebrows upward in an apparently emphatic yes.

"He was grinning the entire time," Diamandis said.