Vehicle development efforts to date have emphasized the balloon. Short test flights of less than five hours have used smaller (5-m diameter) balloons and prototype payloads to prove launch, in- flight control, and recovery procedures. During these flights the innovative balloon envelope recovery system (BERS) and its radio termination system have been tested. Radio frequency interference, compatibility, and distance checks of the prototype command and communication systems have been performed on the ground and in the air. Successful completion of these tests has confirmed the reliability and safety of the GAINS balloon for longer flights.
A major milestone in the GAINS schedule is the 48-h flight of the 18-m diameter prototype, known as the PIII balloon. This payload consists of line-of-sight communications for 3-D position, balloon state, payload monitoring, and other housekeeping parameters. Primary termination is by radio command with several backup systems for two modes of flight termination. Safe operation of the balloon is ensured by an onboard aircraft transponder that keeps the balloon under active air traffic control. A GPS surface reflection experiment for measuring surface winds and soil moisture is also onboard. The physical and electronic integration of the radio and mechanical systems for this test was completed in 2000. Results from the 2-day flight scheduled for September 2001 will be presented.