How did the experiment simulate zero gravity?
To achieve weightlessness, a plane has to free-fall through the air. The Zero-G Airbus A300 that the European Space Agency uses for parabolic flights executes a loop, similar to the way a roller coaster does, to do this. The plane makes a steep 45 degree climb on full throttle, exerting an interior gravity of 1.8. This is more than, but similar to, the extra gravity exerted when people ascend in elevators. After about 20 seconds, the plane is throttled back to just enough to compensate for air resistance, which cancels the force of gravity and puts the plane in free fall. When the angle of flight reaches 45 degrees below horizontal, the plane throttles again to full power, exerting 1.8 G again, and the craft levels horizontally, ready to begin the next loop. By executing 30 of these loops consecutively during a three-hour flight, surgeons are provided with 10 to 11 minutes of weightlessness. Do surgeons continue during normal gravity? When the plane returns to normal gravity at the bot
