New details emerging from the Trump administration’s proposed budget for NASA reveal plans to discontinue the development of an experimental nuclear thermal rocket engine. This engine held the potential to revolutionize space exploration.

The proposed budget includes notable spending cuts for NASA. The White House aims to reduce NASA’s budget by approximately 24 percent,from $24.8 billion this year to $18.8 billion in fiscal year 2026. Programs like the Space Launch System rocket,Orion spacecraft,and numerous robotic science missions,including the Mars Sample Return,probes to Venus,and future space telescopes,face termination. Ars has covered many of the programs impacted by the proposed cuts.

Rather, remaining funds for NASA’s human exploration program would be redirected to support commercial lunar and Martian landing projects.

NASA’s initiatives focused on pioneering next-generation space technologies are also considerably impacted.The White House’s budget proposal suggests nearly halving the budget for NASA’s Space Technology Mission Directorate (STMD), from $1.1 billion to $568 million.

The proposed budget is subject to change. Both houses of congress, currently controlled by Republicans, will draft their own versions of the NASA budget. These versions must be reconciled before being presented to President Trump for his signature.

In an initial overview of the NASA budget request released May 2, the White House stated, “The budget reduces Space Technology by approximately half, including eliminating failing space propulsion projects. The reductions also scale back or eliminate technology projects that are not needed by NASA or are better suited to private sector research and development.”

Nuclear Propulsion on the Chopping block

Last week, the White House and NASA provided more specific details regarding these “failing space propulsion projects.”

According to a technical supplement released Friday detailing Trump’s NASA budget proposal,”This budget provides no funding for Nuclear Thermal Propulsion and Nuclear Electric Propulsion projects. These efforts are costly investments,would take many years to develop,and have not been identified as the propulsion mode for deep space missions. The nuclear propulsion projects are terminated to achieve cost savings and because ther are other nearer-term propulsion alternatives for Mars transit.”

“This budget provides no funding for Nuclear Thermal Propulsion and Nuclear Electric Propulsion projects.”