For an hour and a half or so earlier this month, 30 teachers from Ohio middle schools weighed nothing at all. The same went for me; for TV personality "Science Bob" Pflugfelder; and for 2,016 optic-orange ping-pong balls.

In blue zip-up flight suits and special socks color-coded by team (no shoes allowed in zero gravity!), we flew to a 100-mile-long volume of airspace over Rochester, N.Y., that was set aside for our personal parabolic use. The main cabin of the plane had had its seats removed, to turn it into a giant white cylindrical room padded on all sides. After we reached our designated airspace, we were instructed by the team of coaches to lie on our backs on the padded floor, as the plane began its first of 15 parabolas.

 

First we got heavy, as the plane lifted and we felt acceleration of 2 G's pressing us into the floor's padding. Then suddenly the pilot pulled into his parabola and it became very hard to stay on the ground. The first parabola was designed to simulate Martian gravity; for 30 seconds or so, we all weighed one third of our Earth weights. Science Bob took the opportunity to practice juggling, which, it turns out, is much easier when the balls stay aloft for a nice leisurely amount of time.

There followed two parabolas simulating lunar gravity, a sixth of Earth's, all punctuated by intervals of lying on our backs straining to lift our limbs in heavy double gravity. This slow buildup to the main event is part of the project's scheme to minimize airsickness for its guests; the zero-gravity flights NASA does for its trainee astronauts do not ease in the participants in the same way, and they last much longer; and a bit of vomit in free-fall is common.