In smaller spacecraft such as CubeSat satellites, a salt-based monopropellant is showing promise. The propellant, called FAM-110A, is a mixture of two commercially available salts. It can be used in a combined chemical-electric thruster.
A rocket engine using the propellant could be practical at almost any pressure level; however, it also leaves a significant amount of liquid residue after it burns. This is undesirable because it means that the combustion is incomplete. The formulation requires changes in order to improve efficiency of its combustion.