The centrifuge was activated as soon as possible once the satellite was in orbit and stabilized at 10−3"g" (10 mm/s²). The centrifuge applied gravity stimuli in cycles. Each cycle lasted about 8 minutes, and consisted of the following: a 1-minute period without acceleration, an 8-second period when rotation slowly began, 14 seconds of constant 0.6 "g" (6 m/s²), an 8-second period when rotation slowly stopped, and a 6-minute period when aftereffects of rotation could be measured. Cycles were performed every 30 minutes during the initial 3 hours in orbit, and less frequently during the rest of the flight.