The centrifuge simulates the increased feeling of gravity’s pull during a launch. For astronauts, that’s normally a few minutes at two or three times the force of Earth’s gravity, measured in Gs. Equipment carried in space shuttle cargo bays usually sees between 6 and 7 Gs because of vibration. (The most intense roller-coasters in the world top out at about 5 Gs, and then only for brief moments.)
Goddard’s 120-foot-diameter centrifuge can accelerate a 2.5-ton payload up to 30 Gs, well beyond the force experienced in a launch. Engineers decide how much force to use in a test, and they usually settle on a figure about 25 percent higher than what they expect the equipment will go through during launch. Instruments should be able to handle actual conditions if they hold up to the increased, simulated experience. Two 1,250-horsepower motors help the centrifuge produce that experience. Goddard's centrifuge is only used to test instruments or equipment; no humans allowed.