July 31, 2025 Officials-in-Charge of Headquarters Offices Directors, NASA Centers FROM: Acting Administrator NASA SUBJECT: Directive on Fission Surface Power (FSP) Development Executive Summary • . • Fission surface power (FSP) is both an essential and sustainable segment of the lunar and Mars power architectures for future human space exploration missions.

Nuclear power on the moon is critical to the United States' space exploration and national security goals, and the U.S. government should "move quickly" to build reactors there before its terrestrial rivals,