Description: Deployable aerodynamic decelerators are a low-mass, low-volume option for decelerating interplanetary spacecraft as they approach their destination. A key advantage is that, unlike a rigid aeroshell, they are not constrained by the diameter of the launch vehicle payload shroud. Deployable aerodynamic decelerators, however, require large quantities of gas for inflation. The traditional approach for inflating a deployable decelerator is to use high-pressure helium. Such systems are very simple, but the tank for such a system is very heavy. For example, to inflate a 1200-ft3 decelerator to 30 psia at 300 K requires just over 11 kg of gas, but the titanium tank needed to contain the gas at 6000 psia would weigh over 200 kg. In this project, Ultramet will work with Pennsylvania State University and build upon previous gas generator work that is based on green ionic liquid monopropellants. Specifically, a green propellant with a low flame temperature will be catalytically decomposed using a system that requires virtually no electrical power. The resulting gases will then pass through a bed of endothermic solid that will not only cool the gas to a safe temperature (<200°C), but also generate additional gas in the process. Preliminary calculations indicate that such an approach would reduce the system mass from 212 kg to just 48 kg. It is anticipated that when optimized, even more mass savings can be realized.

Benefits: Aerodynamic decelerators will be the primary NASA application, but the technology could also be used in tank pressurization systems on nearly any spacecraft or satellite because it will be lighter than current systems. Reducing the mass of the inflation system and/or tank pressurization system on a spacecraft will enable it to carry a larger instrument payload or more propellant, thus increasing the scientific capability, life, and/or delta-V capability of the mission. Gas generators could also be used to inflate habitats on the Moon or Mars.

All military and commercial spacecraft, as well as missile interceptors, can benefit from the mass reduction when this technology is used for tank pressurization. Lightweight inflation systems can also be used on commercial aircraft to inflate emergency evacuation slides and for fuel tank inerting.