Fission impossible: Uncle Sam wants nuclear reactors in space by 2031
- Reference: 1776251178
- News link: https://www.theregister.co.uk/2026/04/15/national_initiative_for_american_space/
- Source link:
The [1]initiative [PDF] spells out expectations from an inter-agency perspective: NASA and, as the document refers to it, the Department of War Defense
still its [2]legal name and we're sticking to it – Ed
are to conduct "parallel and mutually-reinforcing" design competitions to develop low- to mid-power space reactors "in orbit and on the lunar surface".The Department of Energy is also involved (it controls the US stockpile of nuclear material). It has been instructed to "provide an assessment on the readiness of the US nuclear reactor industrial base to produce up to four space reactors within five years."
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NASA has 30 days to kick off a program for a mid-power space reactor ready for launch by 2030. A lunar variant is required, as is an option for nuclear electric propulsion.
[4]
[5]
The Department of Defense has 90 days to develop an analysis and use cases for a mid-power in-space reactor by 2031. Its development is "pending availability of funding."
The idea of nuclear reactors in space is nothing new. [6]As recently as 2022 , NASA was planning for a nuclear future on the lunar surface. The agency's acting administrator, Sean Duffy, [7]directed the agency to develop a plan in 2025 , and the current administrator, Jared Isaacman, went further during the [8]Ignition presentation in March , calling for the use of a fission reactor on interplanetary missions as soon as 2028.
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The mid-power reactors will need to provide at least 20 kWe during "at least" three years in orbit and five years on the lunar surface. At least one of the designs must be extensible to 100 kWe, and the initiative calls on NASA to consider a low-power variant that could provide 1 kWe. The low-power option, according to the initiative, "offers lower cost and schedule risk."
[10]Britain's atomic brain trust gives itself till 2030 to unpick fusion challenges
[11]Britain gives Rolls-Royce the nod to sketch out its mini reactor future
[12]DARPA looking for battery that could power a laptop for months
[13]France buys nuclear supercomputing spinoff Bull from Atos for €404M
Launch remains atop whatever is available in 2029, which means one of Blue Origin, SpaceX, or United Launch Alliance crafts. Not in the current roster of launchers is NASA's Space Launch System (SLS), which transported a crew of four astronauts around the Moon in April 2026. The final SLS launch is likely Artemis V, slated for a lunar landing mission in 2028.
The initiative, which spells out the inter-agency cooperation required and the sharing of funding, is an indication that this time the US administration is serious about nuclear reactors in space, after decades of ideas bouncing around NASA and billions spent with little result.
As with many such grand plans, however, much will depend on funding and focus that could extend beyond the end of the present US administration. ®
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[1] https://www.whitehouse.gov/wp-content/uploads/2026/04/NSTM-3-2026_04_14-corrected.pdf
[2] https://www.military.com/feature/2025/10/17/department-of-war-not-legally-what-trumps-executive-order-really-does.html
[3] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2ad-2ImOet6NFU0TrGk7_5QAAAEo&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[4] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44ad-2ImOet6NFU0TrGk7_5QAAAEo&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[5] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33ad-2ImOet6NFU0TrGk7_5QAAAEo&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[6] https://www.theregister.com/2022/06/24/nasa_nuclear_power_moon/
[7] https://www.theregister.com/2025/08/08/nasa_boss_calls_for_nuclear/
[8] https://www.theregister.com/2026/03/24/goodbye_lunar_gateway_nasa_ditches/
[9] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44ad-2ImOet6NFU0TrGk7_5QAAAEo&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[10] https://www.theregister.com/2026/04/15/ukaea_fusion_roadmap/
[11] https://www.theregister.com/2026/04/14/rolls_royce_smr_design/
[12] https://www.theregister.com/2026/04/08/darpa_fusion_firm_radioactive_battery/
[13] https://www.theregister.com/2026/04/01/france_bull_purchase/
[14] https://whitepapers.theregister.com/
It might bring things together.
That's the thing about nuclear scientists/engineers. They are all either splitters or joiners!
Yeah, but what have nuclear physicists ever done for us?
Are we sure that'll work?
I think you'll have difficulty stopping it if you make your reactor big enough. Fuel's cheap though.
RE: Will it work?
What could *possibly* go wrong?
I mean, just because the [1]nuclear aircraft programs failed spectacularly, including fears of radiating an entire continent with fallout if containment fails during an accident, doesn't mean that we should forget about putting radioactive materials in dangerous and unpredictable launch and re-entry vehicles, does it??
Icon: lead-lined, for the Chernobyl-like future.
[1] https://en.wikipedia.org/wiki/Nuclear-powered_aircraft
Re: RE: Will it work?
"I mean, just because the nuclear aircraft programs failed spectacularly,"
Captain Hanson: "Well, with our atomic motors, we can stay up here for six months. But the anti-radiation shield on the reactor will need servicing in two hours, ten minutes, or our passengers will be subjected to radiation exposure."
Fission not fusion
Space junk
It will take rubbish falling from the sky to new levels.
Re: Space junk
Good point.
"Atomic lasers falling from the sky"
The B52s, Channel Z, 1989
"much will depend on funding and focus"
And that is the big problem with democraties - they are led by individuals who mostly don't care about what the previous incumbent thought was a good idea, which means wasted effort and money until, all of a sudden, it becomes a National Priority in which case there's even more wasted effort and money to Get Things Done in haste.
I don't have a solution for that, any more than I have a solution for preventing a country from being under the control a fucking moron, so I won't say more.
Re: "much will depend on funding and focus"
I'd go further and say they often actively try to undo what their predecessor has done, no matter the merits.
Nukes in orbit by 2031?
You could hardly get a nuclear plant operational on Earth by 2031 if you started today. How do they think they're going to manage in space?
Re: Nukes in orbit by 2031?
No NIMBYs, no bat survey, no pretty thatched cottages to be demolished, no road access needed, no seismic assessment, no protesters ...
Re: Nukes in orbit by 2031?
As long as the indigenous rights of the Clangers are respected
Re: Nukes in orbit by 2031?
Protesters aplenty will be down here anyway.
Given that the reactor electrical power requested is "20 kW" (The e in kWe is new to me, I had to look that up...) then I'd be really interested in two things:-
1. what are they going to do with that power that can't be done with less launch mass in solar panels
and
2. I hope they have a plan on how to dump the waste heat from the reactor (maybe 2kW, assuming the reactor is based on those used in submarines), as well as the 20kW of waste heat from using the electrical power.
No problem. The moon only comes out at night. When it's cold and dark. So the waste heat will take care of itself. Well, that's what the Fuckwit-in-Chief tells us and that most stable genius is never wrong,
I'm reminded of one of Feynman's stories. At some meeting of scientists & the military he was buttonholed by a general who told him that what they needed was a mechanism for a tank to scrape up sand as it went and use that as a fuel. It should be easy considering all the other things science had done for them.
Maybe the most honorable general was referring to tar sands?
Should have told him they can do that but if the sand is too fine it clogs up the filters and if it's not fine enough it blocks the jets. But if they carry their own special military grade that is just right then all is well. They call it diesel.
Its been done
[1]BSS 5
Step 1: overthrow the corrupt oligarchy
Step 2 form a government of the people
Step 3, ownership of the means of production and shiny biceps
Step 4, space program
[1] https://en.wikipedia.org/wiki/BES-5
Moon Reactor
1. Build a huge reactor on the moon.
2. Reactor overheats.
3. Reactor explodes.
4. Moon sets off on its own into the galaxy along with Moonbase Alpha.
Though I have to say now I'm not 11 I know that even if it achieved light speed it would still take years to travel between stars and there'd be no hope of slowing an Eagle down enough to land anywhere. Making for a very dull telly show.
Re: Moon Reactor
To be a nerd about this, wasn't it a nuclear waste dump that exploded, launching the Moon off on its journey, rather than a reactor?
I could of course look this up, but that would be cheating - and I'd lose nerd-points.
… for a spacraft to scrape up space as it went and use that as a fuel
Makes as much sense. Do all these blithering generals escape from a Roger Ramjet cartoon ?
" A whole civilisation will die tonight "—Fucking up a reactor in low orbit or during lauch could well give the orange idjit his wet dream.
Having the move fast & break things crew on the job will certainly do the FA and unfortunately we will the ones carrying the FO can.
Did Trump and his lapdog...
...snuggle up on the sofa and watch Iron Sky, gaze lovingly into each others eyes and go " Are you thinking what I'm thing?"
Nuclear fusion in space? Are we sure that'll work?