A parachute opens and floats the payload back to the ground. Recovering the payload allows the experiment package to be reused on another flight. The countdown has begun for Earth-orbiting balloons. NASA presently supports 25 scientific balloon launches yearly witha success rate in excess of 92 percent. The demand for scientific balloons is increasing.
Balloons allow payloads tobe lifted without the vibrations and G-forces associated with rockets.
The payload is recoverable which allows for multiple flights of the same instruments. NASA presently flies conventional and long duration balloons. A conventional balloon flight will last from one to two days while a long duration balloon flight will last up to three weeks. These zero-pressure balloons are launched partly inflated and expand as they rise. They vent some of their gas as daytime temperatures rise in the stratosphere causing the balloon to expand up to its maximum design volume.