NASA's Artemis Program Updates and Discussion Thread 6

[yg1968]

The reactor may be related to the budget in that Congress has been redirecting $100-200M annually for years from the Space Technology Mission Directorate towards space nuclear propulsion earmarks with nothing to show for it.  If Duffy et al. can harness and put that wasteful spending towards an actual flight article, more power to them.

That said, this is more boneheaded, cart-before-the-horse, build-it-and-they-will-come NASA human space exploration sandbox engineering at its worst.  Who is going to use this (potentially multi-billion dollar) 100kW power system?  The human lunar program is lashed to a crew transport system that will deliver four astronauts to the lunar surface for a couple weeks once every year or so.  They’re unlikely to make good use of that large of a power source even when they’re there.  What is going to use this 100kW power system the other 50+ weeks out of the year when they’re not there?  A remotely operated ISRU plant?  No.  A human-tended, partial gravity lab?  No.  A farside observatory?  No.  Is there anything concrete in NASA’s budget and program planning that will actually use this reactor?  No. [...]

And do we really need to plant a reactor on the Moon to declare an exclusion zone?  Aren’t there faster/better/cheaper ways to do that?

We will see what happens but the administration's plan is to have commercial options that will eventually replace SLS. So 30 days mission isn't the long term plan. The long term plan is a permanence presence, 365 days per year with commercial rockets. Furthermore, this power plant technology would be useful for Mars.

Although it probabaly entails one, the objective of the nuclear plant isn't the keep out zone.

[Coastal Ron]

We will see what happens but the administration's plan is to have commercial options that will eventually replace SLS. So 30 days mission isn't the long term plan. The long term plan is a permanence presence, 365 days per year with commercial rockets.

There is not budget, nor any realistic planning, to achieve anything beyond using the SLS. Even assuming the SLS and Orion get dumped, there is no realistic plan to achieve that using so-called "commercial" alternatives - as well as no political will to do that at this point.

Remember the Trump II Administration only has another 3.5 years left, which if they are lucky results in one landing on the Moon. They will have no control over what happens after that.

The objective of the nuclear plant isn't the keep out zone. From drawings that I have seen in the past, the nuclear plant is likely to be mobile.

Are you saying that the plans might require assembly on the Moon? Because that ain't happening with the planned Artemis missions - there won't be the resources to do any serious assembly of such magnitude.

IF a nuclear power plant is built for the Moon it is likely to be completely self-contained, which means it would be mobile. Mobile enough that if left alone on the surface of the Moon that someone could come pick it up and use it while the American's are away for most of the year...

[yg1968]

There is not budget, nor any realistic planning, to achieve anything beyond using the SLS. Even assuming the SLS and Orion get dumped, there is no realistic plan to achieve that using so-called "commercial" alternatives - as well as no political will to do that at this point.

Remember the Trump II Administration only has another 3.5 years left, which if they are lucky results in one landing on the Moon. They will have no control over what happens after that.

We will see what happens next with the FY26 budget but commercial alternatives to SLS were proposed, mostly for Mars but they should also work for the Moon if you combine them with HLS.

Are you saying that the plans might require assembly on the Moon? Because that ain't happening with the planned Artemis missions - there won't be the resources to do any serious assembly of such magnitude.

I deleted that part of my post. It seems that it's mobile for assembly purposes but it isn't mobile after installation. See this presentation for some renderings:

https://forum.nasaspaceflight.com/index.php?topic=55268.msg2381952#msg2381952

[TheRadicalModerate]

It all comes down to this paragraph:

The first country to have a reactor could “declare a keep-out zone which would significantly inhibit the United States,” the directive states, a sign of the agency’s concern about a joint project China and Russia have launched.

I think this is a reasonable argument.  It's a fine way for the Chinese to use the Artemis Accords against the US.  Nothing says "permanent keep-out zone" like a nuke.

Prime real estate at the lunar poles is going to be in very, very short supply.  It needs:

1) A PSR with a viable amount of water.

2) A way into the PSR for equipment.

3) A place to build a base or staging area outside the crater.

4) A place to land equipment near enough to that base.

5) I guess if you have a large enough nuke, you no longer need the base to be on a ridge with access to near-continuous sunlight, but that kinda depends on how much power your water extraction operation draws:  more or less than what a small nuke can provide?

Both China and the US are looking for good ways to humiliate the other.  Even if there's no strategic value to a lunar water operation (I'm not sure that's true), locking the other country out of access is primo humiliation.  I'd like to say that's not a good reason to engage in such a program, but I really can't.

[VSECOTSPE]

We will see what happens but the administration's plan is to have commercial options that will eventually replace SLS.

Not trying to be mean here, but what “plan” to replace SLS?  Where’s that document?  Where’s that procurement?

The President’s FY26 Budget spoke out of both corners of its mouth on SLS.  It criticized SLS costs and schedule but then extended Orion/SLS thru Artemis III.  Cruz then built on that in the reconciliation bill extend Orion/SLS further thru Artemis V and is now demanding a spending plan to ensure implementation:

https://nasawatch.com/congress/house-and-senate-want-a-nasa-obbba-spending-plan-pronto/

The FY26 appropriations bills provide no resources to replace Orion/SLS and focus commercial HLV efforts on Mars landings, not the Moon.

The “plan” is to keep Artemis lunar crew transport shackled to Orion/SLS until long after Trump II is out of office, which is inconsistent with putting a billion dollar-class power source on the surface this decade.

Again, what the heck is Artemis actually going to use a year-round, 100kW power source to do? 

That’s enough for 30 homes.  Are we putting a 30-home base on the Moon?  If not, what then?

Again, what’s the application?  This has been the stumbling block for space reactors from NERVA (I wrote an award-winning paper on this problem in grad school) to Kilopower (which I was an interim PE for at NASA HQ when no one else would step up) to DRACO.  If Duffy et al. don’t address the use case substantively, the program will just be cancelled in a couple or few years like all the space reactors before it.

So 30 days mission isn't the long term plan. The long term plan is a permanence presence, 365 days per year with commercial rockets.

Again, where is the Trump II “plan” to get to a 24/7/365 presence?  The Biden plan (really just Pam Melroy’s) shrank from 60 days to 45 and then 30 and was more engineering taxonomy than plan.

What the heck are astronauts going to do during 365 days on the lunar surface?  How long will crews actually stay and how often will they rotate, is NASA pursuing the transportation and habitation capabilities necessary to support that, and how is NASA building up to these longer stays?

No formal thought has gone into this, forget a published, agreed-to plan.

Furthermore, this power plant technology would be useful for Mars.

It probably won’t be the same reactor.  The heat rejection systems will likely be different and those reach deeply into the core design of a reactor.

That’s not to say the experience won’t help.  But no one should go into this thinking we’ll crank out a second copy of a lunar reactor for Mars on a dime.

Although it probabaly entails one, the objective of the nuclear plant isn't the keep out zone.

Unless I missed something, it’s the only purpose that’s been identified.  Someone is advising Duffy on this.  What use case do they envision for 100kW 24/7 on the lunar surface?  Does that use case pass the sanity test and is NASA pursuing the other elements necessary to support it?  If not, then what the heck are we doing here?

FWIW...

[VSECOTSPE]

Both China and the US are looking for good ways to humiliate the other.

That’s Apollo again with a really expensive waste heat generation substituting for the flags and footprints.

We need internal programmatics that require a 100kW, 24/7 power source to justify and sustain this effort.  Otherwise, like Apollo, it will die prematurely.

[heerohawwah]

Again, what the heck is Artemis actually going to use a year-round, 100kW power source to do?
That’s enough for 30 homes.  Are we putting a 30-home base on the Moon?  If not, what then? 

As someone who works in the energy industry I'm always baffled by comments like this.  100kW is Nothing, yes is more than a family home uses, but its only 130HP.  Your car has more power than that, small jet engines are typically 3-6MW.  Heck the ventilation fans in your office building are probably +100HP.   
 
As for 100kW on demand power, what would you do with it?   

 - Light up a crater so people inside can navigate and find stuff...
 - Charge a rover in an hour instead of days
 - Melt some regolith, run a centrifuge, zap rocks with lasers...
 - Drill a hole
 - Build an industry, everything and anything because you have the power to do so... 

This is why China's plans included a 1MW power plant on the moon.  If you want to do industrial things you need industrial power. 

While I get the rant, any plan regardless of who devised it Trump, Biden, democrat, republican.  Without power it will never happen.  (regardless of whether its electrical power, mechanical power, political power..)

[yg1968]

It all comes down to this paragraph:

The first country to have a reactor could “declare a keep-out zone which would significantly inhibit the United States,” the directive states, a sign of the agency’s concern about a joint project China and Russia have launched.

I think this is a reasonable argument.  It's a fine way for the Chinese to use the Artemis Accords against the US.  Nothing says "permanent keep-out zone" like a nuke.

Prime real estate at the lunar poles is going to be in very, very short supply.  It needs:

1) A PSR with a viable amount of water.

2) A way into the PSR for equipment.

3) A place to build a base or staging area outside the crater.

4) A place to land equipment near enough to that base.

5) I guess if you have a large enough nuke, you no longer need the base to be on a ridge with access to near-continuous sunlight, but that kinda depends on how much power your water extraction operation draws:  more or less than what a small nuke can provide?

Both China and the US are looking for good ways to humiliate the other.  Even if there's no strategic value to a lunar water operation (I'm not sure that's true), locking the other country out of access is primo humiliation.  I'd like to say that's not a good reason to engage in such a program, but I really can't.

It's not a good reason but it plays well in politics and to politicians perception matters a great deal. So get use to it because you will hear it a lot from politicians on both sides. Personally, I don't mind. It's just one more thing in politics that is exagerated. Just about every political issue is like that.

[VSECOTSPE]

As someone who works in the energy industry I'm always baffled by comments like this.

The energy industry doesn’t build terrestrial power plants without a business case.  That goes double for space power sources with many times higher capital costs per watt.  This reactor doesn’t have to turn a profit.  But it should have concrete applications and customers.  There are none.

As for 100kW on demand power, what would you do with it?

It’s not a question of whether there are potential uses for 100kW on the Moon.  It’s a question of which ones Artemis wants to pursue and whether there’s a realistic program to do so.

The history of space reactors is littered with expensive programs that were cancelled when no customer stepped forward (or when planned customers disappeared) to use the system under development.  This latest effort isn’t even trying to identify a use case (aside from occupying lunar real estate so China can’t).  Unless that changes, it will be cancelled after a couple or few years, just like DRACO, KiloPower, NERVA, etc. before it.

This is why China's plans included a 1MW power plant on the moon.  If you want to do industrial things you need industrial power. 

And what industrial application(s) does China want to pursue on the Moon that require a megawatt?  Where are their plans for that?

The western press breathlessly hypes the red threat every time a low-level manager or academic from China gives a presentation on some space topic.  That doesn’t mean they have a properly funded program endorsed by the CCP to do whatever the manager or academic is selling in their presentation.

While I get the rant, any plan regardless of who devised it Trump, Biden, democrat, republican.  Without power it will never happen.  (regardless of whether its electrical power, mechanical power, political power..)

No doubt.  But power to do what?  What is it we’re trying to do on the Moon?

To be clear, I’m not trying to get an accounting of every watt.  But is there something, anything, Artemis is actually planning to do (not what we think the program could do) on the Moon that would justify a billion-dollar plus investment in a surface reactor?

I’m a true believer who has written about and worked space reactor programs.  But so far, this is the most programmatically deficient one I’ve seen.

FWIW…

[yg1968]

We will see what happens but the administration's plan is to have commercial options that will eventually replace SLS.

Not trying to be mean here, but what “plan” to replace SLS?  Where’s that document?  Where’s that procurement?

It's in the FY26 Budget. There is a request for 864.1M on page 3:
https://www.nasa.gov/wp-content/uploads/2025/05/fy-2026-budget-technical-supplement-002.pdf

In terms of the Appropriations bill, my understanding is that the other exploration funds could be used for it as NASA isn't precluded from funding commercial alternatives to SLS. Of course, the FY26 Budget is still being debated right now, so this isn't a done deal by any measure (including the proposed science cuts that you are taking for granted).

Incidentally, I am not sure why there is a 30 day limit to SLS/Orion missions. Bridenstine had said that it was because of budgetary reasons. But I wonder if it is also partly because of the lack of a reliable and continuous power source?

[Proponent]

Which part of NASA would manage the 100-kW reactor? Power is Glenn's specialty, but could this be given to MSFC as compensation for the proposed cancellation of EUS?

[yg1968]

Which part of NASA would manage the 100-kW reactor? Power is Glenn's specialty, but could this be given to MSFC as compensation for the proposed cancellation of EUS?

I don't know the answer but NASA was already funding studies for a 40-kw nuclear reactor prototype, so presumably the same people would be involved.

[VSECOTSPE]

It's in the FY26 Budget. There is a request for 864.1M on page 3:

A line on a budget spreadsheet is not a program plan.  And for intents and purposes, it’s probably been zeroed out in the appropriations bills anyway to pay for all the other things appropriators actually highlighted in those bills.  (If Republican appropriators planned to fund that or any other element of Trump’s request, they would have highlighted such.)

Incidentally, I am not sure why there is a 30 day limit to SLS/Orion missions. Bridenstine had said that it was because of budgetary reasons. But I wonder if it is also partly because of the lack of a reliable and continuous power source?

Longer missions durations were dependent on the capabilities of a “mobile hab”, which a stationary reactor wouldn’t help with.

Maybe Duffy & Co. will dump the mobile hab, but again, nuclear cart before the hab horse, where’s that plan (or just decision)?

(including the proposed science cuts that you are taking for granted).

I don’t take the cuts for granted.  Under a normal administration, the support for NASA science in the draft appropriations bills would have ended the possibility of those cuts ending (nearly) any missions.

I take seriously Trump II/OMB actions and threats to terminate federal R&D and other programs in spite of Congressional funding and support and what that could mean for NASA’s science missions.

FWIW...

[VSECOTSPE]

I don’t agree with everything in this op-ed, but his point about the lack of leadership in the federal space sector is well-taken:

https://thehill.com/opinion/white-house/5428487-trumps-first-term-space-policy-was-great-but-now-hes-dropping-the-ball/

[hektor]

NASA Selects Six Companies to Provide Orbital Transfer Vehicle Studies

[TheRadicalModerate]

Both China and the US are looking for good ways to humiliate the other.

That’s Apollo again with a really expensive waste heat generation substituting for the flags and footprints.

We need internal programmatics that require a 100kW, 24/7 power source to justify and sustain this effort.  Otherwise, like Apollo, it will die prematurely.

Nothing says "keep away from me" quite like a nuke.  For good or ill (mostly good, I think), we've wound property rights in space together with due regard and non-interference.  A nuke makes a hell of a property stake.

Beyond that, I don't think it's nearly as big a deal as it might be.  Kinda depends on the regulatory framework, but the reactor is pretty small, and all you need to prove is that it's going to stay encapsulated and in cold shutdown in the event of a launch accident.  If you have an accident on the Moon?  Meh.  If you're proving out stuff for a base, better to land the nuke first and have it fail than having it fail when there's a whole bunch of other stuff already there.

I thought Kilopower was supposed to scale to 100kWe.  That gives you a TRL 7-ish reactor, with abundant launch and landing systems.

As for 100kW on demand power, what would you do with it?   

 - Light up a crater so people inside can navigate and find stuff...
 - Charge a rover in an hour instead of days
 - Melt some regolith, run a centrifuge, zap rocks with lasers...
 - Drill a hole
 - Build an industry, everything and anything because you have the power to do

Two things:

1) You need to add "keep stuff from freezing solid while unoccupied during lunar night" to your list.

2) If the winner is something very close to Kilopower, it should be easy to scale just by adding units.

Would I prefer a 1MW form factor?  Sure.  Would I prefer it if it means delaying deployment by 5-10 years?  Nope.

[VSECOTSPE]

Nothing says "keep away from me" quite like a nuke. 

Accelerate the survive-the-night kit for CLPS landers and put a small telescope susceptible to lunar dust getting kicked up around it on one and boom — exclusion zone for a tenth the (optimistic) cost of a surface reactor and probably a faster and bigger one to boot.

An exclusion zone can’t be the raison d’etre for a lunar surface reactor.  It’s job is to supply power to one or more applications worthy of its cost, not occupy real estate in the most expensive way possible.  What are those applications?

If the only or driving purpose for a surface reactor is to take up lunar real estate, it will die as soon as that competition with China is won or cools down, just like Apollo did.

My complaint isn’t about space reactors per se, on the Moon or anywhere else.  My complaint is about the long list of space reactors that got cancelled because they had non-existent customers and lousy programmatic justifications, and the fact that this reactor is even more poorly rationalized than all of those prior ones.

I thought Kilopower was supposed to scale to 100kWe.  That gives you a TRL 7-ish reactor, with abundant launch and landing systems.

Kilopower’s last test reactor was KRUSTY, which was designed to produce 100kW using a HALEU fuel source, but was only ever tested using depleted uranium.  It produced 5.5kW and represented a TRL 5 test.  Other than the fact that nearly all these microreactors intend to use a HALEU fuel source, I don’t know how much of KRUSTY’s technical approach will be reflected in the commercial proposals.  They may build off totally different approaches to terrestrial microreactors.

What exact TRL or power level Kilopower achieved is losing the forest for the trees, IMO.  It’s not lack technical readiness or design choices that have killed prior space reactors.  It’s lack of applications and customers.  This will optimistically be a billion dollar-plus investment.  It’s not going to optimistically launch until after Trump II has been out of office for a couple years.  Without customers saying they want/need this and applications worthy of the cost and bureaucratic headaches necessary to get it flown, it will die well before flight, just like every US space reactor before it.

FWIW...

[Eric Hedman]

The one thing a nuclear plant could supply power to on the Moon could be this:

https://www.thalesaleniaspace.com/en/news/lunar-multi-purpose-habitat-activities-officially-underway

I don't know what its power requirements will be if this gets built,  But I think it could be the first customer.

[catdlr]

Seems the budget may focus on heading to Mars:   (this will also be posted on the Mars thread);

NASA’s proposed budget eyes human exploration of Mars

ARTICLE:

Musk response:

Slight chance of Starship flight to Mars crewed by Optimus in Nov/Dec next year. A lot needs to go right for that.

More likely, first flight without humans in ~3.5 years, next flight ~5.5 years with humans.

Mars city self-sustaining in 20 to 30 years.
2:39 AM · Aug 6, 2025
·

https://x.com/elonmusk/status/1953028261044187204

[catdlr]