A high-altitude test of inflatable wings for low-density flight applications

Recent projects involving unfolding rigid-wing aircraft have demonstrated high-altitude, low-density flight capabilities, moving the concept of an unmanned aircraft exploring Mars or Venus nearer to reality. Motivated by the requirement for a minimal packed-volume-to-weight ratio, an alternate approach for the wing design is an inflatable wing. Two previous balloon-launched high-altitude experiments have successfully demonstrated the feasibility of deploying and curing inflatable/rigidizable wings. Rugged inflatable wings constructed of materials used for the Mars Lander airbags with maintained internal pressurization are also a viable alternative for both high-density and low-density flight applications. Low-altitude flight tests have demonstrated high reliability, along with their unique ability for wing shaping to expand flight capabilities. This paper presents the development and results of a successful high-altitude test to demonstrate the feasibility of rugged inflatable wings for planetary exploration. Flexible solar cells were mounted on the wing surface to illustrate the potential for multifunctional inflatable structures with power generation capabilities as well. The balloon-launched experiment concept is described, along with details of test article design, fabrication and ground testing. The flight test was conducted on April 30, 2005. The wings were deployed at approximately 96,000 ft, reaching a maximum altitude of 97,987 ft. The test article descended under parachute to recovery. Flight results, including onboard images, temperatures, pressures and solar cell power are included.