XEUS, the eXperimental Enhanced Upper Stage, fulfills a need for an affordable, large commercial lunar lander vital to creating a cis-lunar economy and developing recurring activities beyond LEO. XEUS enhances ACES with a mission kit to enable the stage to reach destinations beyond LEO and function as a lander upon arrival. Several elements of the XEUS system are already under development. ACES provides a high mass fraction structural backbone, powerful avionics package, reliable main propulsion system, and other subsystems necessary to travel to the moon. A Masten Space Systems mission kit provides entry, decent, and landing (EDL) flight software, landing sensors, and distributed landing propulsion to achieve precision landings in challenging terrain. Most mission kit technologies build upon Masten’s XL-1 lunar lander, which features extensible GNC flight software and 6 DOF simulator applicable to systems using multiple engines, different sensors, and different environments.

This unique combination of hardware and technologies yields lower development cost, risk, and schedule. Additionally, the XEUS design infuses lessons learned from previous, conventional lander designs to provide an optimized lander system built to deliver large payload and cargo masses to the lunar surface, such as base infrastructure, large rovers, scientific payloads, and ISRU production equipment. This means fewer launches from Earth are required to deliver payloads to lunar destinations, opening the door more quickly and at reduced cost to help build a self-sustaining cis-lunar economy. XEUS is an innovative solution to the ongoing challenge of creating affordable and reliable access beyond LEO.