Gravity, zero

thrills, countless

Weightlessness: Students experience zero gravity and are exhilarated despite also experiencing motion sickness.

April 29, 2003|By Michael Stroh | Michael Stroh,SUN STAFF

OVER THE GULF OF MEXICO - Four turbojet engines howl as the KC-135 rockets upward into a clear blue sky 200 miles south of Houston. In the heavily padded cabin of the former aerial tanker, Michael Sharma braces himself for an experience that few earthlings will ever share - weightlessness.

Is he excited? Proud? Jittery?

"Queasy," groans the Johns Hopkins University junior as the blood drains from his face.

Such is the human cost of conducting research in one of the world's most unusual laboratories - and exclusive thrill rides.

Sharma and a handful of budding scientists from 12 colleges around the country have won a rare chance to perform experiments outside of the pull of gravity. But loosing the bonds of Earth requires a trip on an experimental NASA aircraft known officially as the Weightless Wonder - and unofficially by a more notorious nickname: the Vomit Comet.

On this day, at least, the aircraft lives up to its reputation, in a wild 120-minute roller coaster flight that leaves Sharma and the rest of the students sick, exhausted - and exhilarated.

"I'd do it again in a heartbeat," he says afterward.

Since the dawn of the space age, the National Aeronautics and Space Administration has relied on zero-gravity maneuvers in planes such as the Comet to give astronauts a taste of weightlessness and to test equipment from shower heads to space suits before launching them into orbit.

The aircraft, a cousin of the civilian Boeing 707, played an off-screen role in the 1995 film Apollo 13, allowing Tom Hanks and other cast members to create many of the movie's zero-gravity scenes.

Since then, NASA has used the Comet to spark interest in science and space flight among undergraduates, who compete to fly aboard the aircraft by proposing and building often elaborate experiments. Sharma and his Hopkins teammates are measuring how well liquids mix in a weightless environment.

The plan when the Hopkins team boards April 17 calls for 40 gut-grinding parabolic arcs through the air, each culminating in 25 seconds of weightlessness. By the time it's over, everyone will have had more float time than astronaut Alan B. Shepard got on the first U.S. manned space flight in 1961.

On the morning of their adventure, the students arrive at 7:30 a.m. for the preflight briefing. First order of business: drugs.

60% become ill

Motion sickness can be a serious problem on the Weightless Wonder. Dr. James Locke, the NASA flight surgeon assigned to the group, calls zero gravity "a lot for the brain to handle." According to the official aircraft handbook, 60 percent of those who fly become ill.

Since the student program began, only eight flights have returned to the tarmac without a single "kill," the flight crew's tactful term for someone separated from his breakfast. A "no kill" flight is so rare that the Comet's hangar bears a plaque honoring the first one.

To help reduce the risk, Locke passes out packets of anti-nausea pills called Scop-Dex. Students notice that some of the tablets have the word "Hope" engraved on their surfaces. Not sure what to make of the message, they take no chances and shove fists full of airsick bags into their olive-colored flight suits.

Half an hour after takeoff from Houston's Johnson Space Center, where the Weightless Wonder is based, the aircraft reaches its reserved airspace off the Texas coast.

From that point, flying the KC-135 smoothly into zero gravity demands "a little bit of art," says Frank Marlow, one of its pilots. It's an art developed before space flight, when the military was first trying to understand the effects of weightlessness on the human body. The big problem was how to turn off Earth's gravity to find out.

In 1950, two Air Force scientists, brothers Fritz and Heinz Haber, came up with the theory that flying an airplane in the same parabolic path a lobbed baseball takes might do the trick.

As the plane reaches the top of the arc, known in the trade as a Keplerian trajectory, the pilot cuts power and puts the craft into free fall, resulting in a few seconds of weightlessness for everyone aboard. Or so the Habers believed.

Two Air Force pilots were ordered to test the theory. One of them, Chuck Yeager, was already famous as the first man to break the sound barrier. He also became one of the first humans to experience weightlessness.

"Lost in space" was the way Yeager summed up the feeling. Ever since, people have struggled to put the feeling of weightlessness into words.

"Is it like an amusement ride gone bad?" a student from Ripon College asks before the flight. Dominic Del Rosso, a Comet crew member who has logged more than 8,000 zero-gravity parabolas, can't help her. "After all these times," he says, "I still can't describe it."

Aboard the aircraft, the students are about to find out. The KC-135, cruising at 24,000 feet, rears up into a steep 50-degree climb. Then, as it approaches the top of its arc, the pilot cuts the engines, and fluorescent lights mounted around the cabin suddenly flicker on.

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