What energy storage technologies can be used to power electric motors that drive rocket engine propellant pumps for the Artemis human landing system craft?
DSIAC is looking for information to support the National Aeronautics and Space Administration (NASA) with identifying and compiling candidate technology (battery, fuel cell, supercapacitor, etc.) to use to power electric motors that drive propellant pumps for a liquid-oxygen/liquid-methane (LOX/LCH4) rocket engine used on the Artemis human landing system craft.
The spacecraft could be in transit for up to 4 months from the time of launch before the engine would be needed for descent to the Lunar surface. The engine is expected to fire for 6 minutes, requiring 106 kW for both pumps combined. If the solution is battery-based, it must discharge at a 10C rate to minimize leftover energy at the end of 6 minutes. For a battery-based solution, the desired cell energy density is ≥250 Whr/kg at the 10C discharge rate and operating temperature range specified in the imbedded chart, which summarizes the required parameters. Cryogenic fluids are available for cooling if required/desired to enhance or maintain performance or reduce size/weight requirements. Reusability is not a constraint, and the energy storage device is only required to discharge once.
There are several reasons to consider this engine for the lander. This type of engine is significantly simpler in design compared to an equivalent turbopump engine. Eliminating the turbine reduces development time and cost of the engine substantially. Also, using electric motors to drive the pumps provides deeper throttling capability and simplifies the engine valves' design. The considered engine size meets the descent element thrust requirement when clustered in a group of three engines. A single engine meets the ascent element thrust requirement. This common engine possibility is another benefit that could help reduce cost and development time.