Ultra-High Altitude Balloon (UHAB)

The expanding use of scientific balloons as a cost-effective alternative to orbital and suborbital space flight has driven the development of Ultra-High Altitude Balloon (UHAB) vehicles. Of particular interest is the ability to fly payloads approaching 900-1,000 kg to altitudes in excess of 45 km using traditional zero-pressure designs. A zero-pressure balloon of nearly 1.7 million cubic meters (60 million cubic feet) volume was developed for NASA and launched in Summer 2002. This was the largest balloon ever successfully flown, reaching an altitude of 49 km.

The altitude that is achievable with a scientific balloon is limited by the available material strength and thickness along with the physical production space available. The length of the Raven balloon plant is 244 m, which limits the maximum volume of a producible balloon to approximately 2.1 mcm. The thinnest film producible using the currently available SF-430 process is 5 µ. Using the maximum possible volume and the thinnest possible shell results in a 2.1 mcm balloon that weighs 774 kg and could theoretically carry 60 kg to 56 km.