In smaller spacecraft such as CubeSat satellites, a salt-based monopropellant is showing promise. It can be used both in high-thrust chemical propulsion for fast time-sensitive maneuvers, and electric mode for slow maneuvers, such as orbit maintenance. Now, researchers have more knowledge about how it performs under pressure to inform rocket design.

The propellant, called FAM-110A, is a mixture of two commercially available salts.

«Unlike hydrazine, the most commonly used monopropellant available today, our mixture is nontoxic. It’s also denser, so a smaller tank can be used for storage. And because it can be used in a combined chemical-electric thruster, it requires less plumbing than two separate thruster systems with their own propellants,» said Nicolas Rasmont, a graduate student who is working with AE faculty member Joshua Rovey.

Rasmont said his research project looked at the velocity of its combustion in the high-thrust chemical mode and how it performs under different pressures. The findings will help inform the design of a rocket engine using this type of propellant.

«We learned that the preparation and storage conditions have a deeper influence on combustion velocity than we anticipated,» Rasmont said. «We don’t have a complete explanation for that, yet. We think it’s because FAM-110A can absorb moisture from the atmosphere very quickly. Both components are hygroscopic, and other researchers found that even a small increase in water content can alter the combustion properties of similar propellants.»

The experiment studied FAM-110A along with two controls whose combustion behaviors are well known: nitromethane, and a mixture of 80 percent HAN with 20 percent water. The propellants were subjected to a range of pressures from 0.5 to 11.0 Megapascal, while a high-speed camera captured images of the flame to calculate the burn rate.

Story Source: Materials provided by University of Illinois Grainger College of Engineering. Note: Content may be edited for style and length.