WITNESS: Zero G -- like being born

Tim Hepher has been a journalist with Reuters for 14 years, with experience covering trade wars and takeover battles, and now specializes in aerospace business in Paris. In the following story, he describes a parabolic flight where he somersaulted weightless with space officials and politicians.

By Tim Hepher

BORDEAUX, France (Reuters) - Nothing quite prepares you for becoming weightless, except perhaps being born.

Aboard a specially converted Airbus airliner to experience a parabolic flight organized by France's space agency CNES, I am first pressed and squeezed by a force far greater than me.

Then, dangled upside down as if by an invisible hand, I feel almost unbearably light as I try to find my bearings in a completely new element. Fifteen roller-coaster maneuvers later, I feel like kicking away the prop of gravity for good.

My companions in this journey of kinetic discovery are European politicians and space agency directors. As part of efforts by CNES to persuade more countries to use its "zero G" conditions for scientific research, VIPs fill the air.

The night before we got airborne, I found these European space experts in a hotel lobby debating G forces and physics.

They explained that zero G does not mean an absence of gravity, but freefall. Even orbiting astronauts are subject to gravity: they just feel weightless as they tumble in space.

Consider the sensation of lightness you get in an elevator as it starts to go down -- and heaviness as it rises -- the experts said. If the ropes were to snap, you would be in freefall inside an object which is also in freefall, and so feel weightless.

Like the elevator, a spaceship in orbit keeps falling -- but over the horizon -- following the earth's curvature. Our plane ride would give us that experience by briefly tracing a similar curved path, like water droplets flicked up from a hose.

"Think about throwing a rock or a ball. If there is no resistance it goes into a parabola," said fellow passenger Bo Andersen, director-general of the Norwegian Space Center.

"If you throw hard enough, it will follow the curvature of the earth and you have to duck or it will hit you from behind."

Glancing over my shoulder, I headed for the safety briefing.

IGNORING ALARMS

There, French astronaut Jean-Francois Clervoy, who runs Novespace, the CNES subsidiary operating the plane, explained how the aircraft would create weightless conditions by plowing through a series of parabolic arcs across the sky.

The plane looks from the outside like a normal jetliner. But after climbing steeply, our A300 would become an aluminum tube in semi-controlled freefall until the pilots brought it gradually back to level flight.