Innovations in materials, structures, and systems concepts have enabled buoyant vehicles to play an expanding role in planning NASA’s future Solar System Exploration Program. Balloons and aerobots containing science instruments can cover large distances in short periods of time, and obtain science data from otherwise inaccessible locations. Key planetary exploration targets of interest include Saturn’s moon Titan, and the planet Venus.
Titan Montgolfiere Balloons: Recent NASA mission studies have recommended the use of radioisotope-heated Montgolfiere balloons for future in situ Titan exploration. Technologies are sought for the design, fabrication, and Earth atmosphere flight testing of prototypes that could support an eventual Titan Montgolfiere balloon mission. Particular importance is attached to the acquisition of test data that could help validate thermodynamic and fluid mechanic models that would ultimately be used to design the Titan flight balloon. The balloon size required for Titan would be approximately 10 m in diameter, and would require 2 kW of thermal energy to float the balloon at an expected Titan temperature of 85 to 95 K. Any proposed Earth-test prototype would require an alternate heat source that adequately mimics the effects of using radioisotope energy at Titan.
Gas Management Systems for Titan Aerobots: Hydrogen-filled aerobots at Titan must contend with the problem of gas leakage over long-duration (1 year or more) flights. Technologies are sought for the development and testing of two kinds of prototype devices that could be carried on the aerobot to compensate for these gas leakage problems. One device would be to produce make-up hydrogen gas from atmospheric methane; the other device would be to remove atmospheric gas (mostly nitrogen) that could leak from the ballonets into the hydrogen-filled blimp. Both kinds of devices would need to operate on no more than 15 W of electrical power each while compensating for a leakage rate of at least 40 g/week of hydrogen or 500 g/week of nitrogen.
Metal Balloons for High-Temperature Venus Exploration: Balloons made of metals are a potential solution to the problem of enabling long-duration flight in the hot lower atmosphere of Venus. Technologies are sought for metal balloon concepts and prototypes that could provide 1-5 m3 of fully inflated volume, areal densities of 1 kg/m2 or less, sulfuric acid compatibility at 85% concentration, and operation at 460 °C for a period of up to 1 year.
Balloons and airships are expected to carry scientific payloads at Titan and Venus that would perform in situ investigations of their atmospheres and near-surface environments. Both Titan and Venus feature extreme environments that significantly impact the design of balloons for those two worlds.