Abstract NASA/Wallops Flight Facility (WFF) developed an Ultra-Long Duration Balloon (ULDB) balloon support system that was flown on a balloon test flight at Fort Sumner, NM in May of 2001. The objectives were to develop a flight support system that would meet the generic requirements of supporting ULDB missions for up to 100 days. The flight system consists of hardware and software elements including RF communications, power system, attitude control, command and data handling, thermal control and mechanical structures. An overview of the flight support systems is presented along with the results from the balloon test flight. A key result of this test flight was the proven capability to transmit 150 kbps through a newly developed TDRSS high gain antenna. In addition, the balloon flight support system is currently being reconfigured to support the Cosmic Ray Energetics and Mass (CREAM) mission scheduled for launch out of Antarctica in December 2003. The technical capabilities and performance of the flight support system has been analyzed in light of limited resources to support the CREAM mission. A discussion of the technical trade-offs that has resulted in a baseline design to meet the CREAM mission requirements will be presented.