To Mars via the Atom

NASA and the United States Defense Advanced Research Projects Agency (DARPA) announced on Tuesday, 24 January 2023 a collaboration to demonstrate a Nuclear Thermal Rocket (NTR) engine in space. Such engines, fully developed and thoroughly vetted, might one day power NASA manned missions to Mars.

Per a non-reimbursable agreement, NASA will join DARPA's Demonstration Rocket for Agile Cislunar Operations (DRACO) program—an initiative undertaken in 2021 for purpose of developing a nuclear thermal engine by which an experimental, DARPA-designed spacecraft will eventually be powered. Subject agreement grants NASA final authority over the nuclear thermal rocket engine's development and fabrication. DARPA, conversely, is granted authority over the eXperimental NTR Vehicle (X-NTRV), the spacecraft that will be powered by the inchoate nuclear rocket engine. DARPA will be responsible, also, for the orbital operation and ultimate disposal of the X-NTRV.

NASA administrator Bill Nelson called the joint undertaking an “"exciting investment in the future of human space exploration" and "a major investment in getting to Mars."

NASA Deputy Administrator Pam Melroy added: "DRACO will be a critical part of evaluating the technologies that will take us deeper into the solar system. Our intent is to lead and develop a blueprint for human exploration and sustained presence throughout the solar system. That is a very important goal. And we think that these advanced technologies will be a critical part of it."

The notion of a nuclear thermal rocket is neither new nor revolutionary. NASA’s Nuclear Engine for Rocket Vehicle Application (NERVA) program spanned two decades between the mid-1950s and the mid-1970s, and succeeded spectacularly—albeit to little avail.

A joint effort of NASA, the U.S. Atomic Energy Commission (AEC), and the Space Nuclear Propulsion Office (SNPO), the NERVA program set out, initially, to develop nuclear propulsion architectures for United States Air Force intercontinental ballistic missiles.

In 1958, the enterprise was reclassified a civilian program and shifted its focus to the development of a nuclear-powered upper-stage for NASA’s Saturn V moon rocket. NERVA was deemed a highly successful program insomuch as it met or exceeded the entirety of its program goals, thereby demonstrating that nuclear thermal rocket engines were a feasible and reliable tool for space exploration. At the end of 1968, the SNPO set forth that the latest NERVA engine, the XE, met the requirements for a human mission to Mars.

Notwithstanding sound design, successful testing, expert endorsement, and strong political support, the NERVA program never actualized its goals. Federal budget cuts and pressures born of escalating Cold War tensions compelled U.S. national priorities otherwise, and in 1973, a stroke of President Richard M. Nixon’s brought the NERVE program to an end.

FMI: www.nasa.gov