A Solar Thermal Steam Propulsion System Using Disassociated Steam for Interplanetary Exploration

Sustainable space exploration will require using off-world resources for propellant generation. Using off-world-generated propellants significantly increases future missions’ range and payload capacity. Near Earth Objects (NEOs) contain a range of available resources, most notably water-ice and hydrated minerals. However, water-bearing regolith needs to be excavated and the water extracted. Water is a compelling choice for fuel as it is readily available in interplanetary space and easily stored. In this paper, we propose using solar concentrators, which can efficiently convert incident sunlight into heat without the need for moving parts. When water is heated up to 4000 K, a value consistent with high-performance refractive materials, it experiences significant disassociation into H₂, O₂, OH, H, and O components, providing a path for adding considerable additional chemical energy per degree of temperature increase, and producing theoretical specific impulse (I_sp) values in the range of 643 s to 659 s.