The reactor would launch to the moon by 2030, according to a directive by Acting NASA Administrator Sean Duffy that was sent to NASA officials in July and obtained by NPR. It's an ambitious target that has some in the scientific community concerned about high costs and a potentially unrealistic schedule.

Nuclear power in space isn't a new idea. Since the 1960s, the US and the Soviet Union have relied on radioisotope generators that use small amounts of radioactive elements to power satellites.

NASA’s interim chief Sean Duffy has made deploying a nuclear reactor on the Moon his top priority, framing the effort as a "second space race". Washington hopes to beat Beijing and Moscow to powering a future lunar base with nuclear energy.