Here's an excerpt from President Tump's EO 13972 Jan. 5, 2021:
"On August 20, 2019, I signed National Security Presidential Memorandum-20, entitled "Launch of Spacecraft Containing Space Nuclear Systems," calling for development and use of space nuclear systems to enable or enhance space exploration and operational capabilities..."
Here's an excerpt from President Tump's EO 13972 Jan. 5, 2021:
"On August 20, 2019, I signed National Security Presidential Memorandum-20, entitled "Launch of Spacecraft Containing Space Nuclear Systems," calling for development and use of space nuclear systems to enable or enhance space exploration and operational capabilities..."
Here's the link to Memorandum:
https://trumpwhitehouse.archives.gov/presidential-actions/presidential-memorandum-launch-spacecraft-containing-space-nuclear-systems/
Here's the link to the EO regarding small nuclear reactors that includes mention of the Memorandum
https://www.presidency.ucsb.edu/documents/executive-order-13972-promoting-small-modular-reactors-for-national-defense-and-space
I would posit that these portable nuclear power devices are already in use in places like Antarctica and deep underground military bases etc
Gotta be uranium tho right, couldn't use something safer like thorium