NASA test flights with increased flight stress indices

This paper presents the objectives, results, and conclusions stemming from a series of six test flights conducted for the National Aeronautics and Space Administration (NASA) by the National Scientific Balloon Facility (NSBF). Results from the test flights indicate that: (1) the current two U.S. balloon films are capable of being flown at significantly increased flight stress index values; (2) payload weights less than the design minimum payload can be reliably flown without fear of structural failure due to increased circumferential stress; and (3) large and rapid decreases in payload weight can be tolerated by current balloons without structural failure.