Will SpaceX use NASA Kilopower Nuclear Reactors?

[Jcc]

As NASA's Kilopower program undergoes it first tests, will it be a suitable technology for SpaceX Mars plans?

On the plus side, it is already under active development and is likely to be the first practical fission power system to get approval for flight to the Moon and Mars, it is compact lightweight and you can take several of them.

On the minus side, a 1 kilowatt nominal initial rating is too small for Mars colonization plans, and you would need a very large number of them, or much higher power.

This design uses an "umbrella deployed" radiator to send waste heat to the thin Mars atmosphere or a vacuum, I have heard some suggestions that you really want to send waste heat into the Martial soil as it can conduct heat more efficiently, and possibly use the waste heat for habitats or industrial purposes.

Kilopower is meant to use Stirling engines to spin a generator. Is there a better approach? 

https://www.nasa.gov/directorates/spacetech/feature/Powering_Up_NASA_Human_Reach_for_the_Red_Planet

https://www.scientificamerican.com/article/nasa-seeks-nuclear-power-for-mars/

[John Alan]

Kilopower is meant to use Stirling engines to spin a generator. Is there a better approach? 

No... not really... my opinion...
A well made, high pressure Helium, Stirling engine is a good choice for the application...

Hooked to a battery bank... it could sit there making 1000 watts all the time...
But the battery could serve a surge load of many times that for a short period
 

[deruch]

FISO presentation from February: 
"Kilopower: Small Fission Power Systems for Mars and Beyond"  http://spirit.as.utexas.edu/~fiso/telecon/Mason_2-1-17/
Lee Mason

I don't recall if Lee discusses SpaceX specifically, but it gives a very nice overview of the project and goals.  For SpaceX focus, I know Tom Mueller mentioned it during his talk with they NYU Astronomy Society that was recorded and widely discussed.  I think he even mentions SpaceX partnering or participating in the Kilopower project.  Though, I don't recall any details actually being mentioned.

[Jcc]

Noting from the linked presentation, they envision 10kW class systems going to Mars, so that is an order of magnitude better than what I mention in the OP.

Even if these systems are available for early SpaceX Mars flights, they will deploy solar also, but need nuclear when available.

[meekGee]

For what SpaceX wants, they need ~MWatt almost immediately - and much more shortly afterwards.

Just fuel and oxygen production, digging and trenching, construction...

I'm still waiting to hear the specifics of what the power plan is.

[john smith 19]

For what SpaceX wants, they need ~MWatt almost immediately - and much more shortly afterwards.

Just fuel and oxygen production, digging and trenching, construction...

I'm still waiting to hear the specifics of what the power plan is.

True, and for the foreseeable future they will be using PV arrays as the primary system.

But they don't run at night and Martian nights can get pretty cold. One or more Kilopower units makes a very useful insurance policy, given that we know  months long sand storms have happened before. You can also deep discharge cells in sequence, knowing you have the power to reliably charge them

In an ideal world SX would be able to acquire a naval reactor, which is about the right size. Unfortunately they are geared up to dump heat into an ocean of water. You could argue that a glacier is an ocean of (frozen) water, but we have no idea if it's a giant ice cube, or more like permafrosted mud.

And of course there is no navy that will let them have one.  this is one system that SX really can't do in house.

FISO presentation from February: 
"Kilopower: Small Fission Power Systems for Mars and Beyond"  http://spirit.as.utexas.edu/~fiso/telecon/Mason_2-1-17/
Lee Mason

I don't recall if Lee discusses SpaceX specifically, but it gives a very nice overview of the project and goals.  For SpaceX focus, I know Tom Mueller mentioned it during his talk with they NYU Astronomy Society that was recorded and widely discussed.  I think he even mentions SpaceX partnering or participating in the Kilopower project.  Though, I don't recall any details actually being mentioned.

One of the take aways from the Mueller presentation (I think it was sumarized on the BFS 0.2 thread) was that SpaceX is talking to NASA about KiloPower.  He was vague on details and there was no indication if SX was actively supporting it (IE part funding it or supplying staff). As a US corporation SX would have standard access rights to the results when published.

This months Kilopower full test (excluding the radiators, which will vary a lot depending on space or planet and uses for the waste heat) is 1Kw but I think there's a test series at the end (time, money, no issues permitting) that lays the ground work to go up to 10Kw.

The nice thing about KiloPower is it's granular. .
A 1Kw unit is a viable RTG replacement without the hassle of Pu241 mfg.  Attractive for mission planners to start penciling it in now.
A 10Kw unit is good enough to run an ion thruster to the outer planets with huge delta v and then run a big (by current standards) suite of instruments when it gets there.
On Mars they have already pivoted the DRM 5.0 architecture away from a single (point of failure) big reactor to multiple KiloPowers. That also means you carry 1 of 7 of them as a spare, whereas before it was carry 2 reactors, which was much bigger.

IOW There are quite a lot of stakeholder in NASA would like it to succeed.

The especially nice features are the 24/7/365 operation and the fact the can be made on a series basis, not a lovingly crafted one off.

[Ludus]

For what SpaceX wants, they need ~MWatt almost immediately - and much more shortly afterwards.

In an ideal world SX would be able to acquire a naval reactor, which is about the right size. Unfortunately they are geared up to dump heat into an ocean of water. You could argue that a glacier is an ocean of (frozen) water, but we have no idea if it's a giant ice cube, or more like permafrosted mud.

In order to make large quantities of propellant to meet the planned ISRU they need a settlement site with a lot of available water as well as a lot of power. Water to cool a reactor shouldn’t be an issue since they need it anyway prepped to feed into the ISRU plant. Whether it’s pure or like permafrost that’s what they have to design the process around, so they have some incentive to pick a site where it’s easier.

There are a lot of Small Modular Reactor designs in development that might be suitable too.

Not that the little 10k plants won’t be useful too.

I’d think with large amounts of Methane and LOX stored they’d have some use for Methane Fuel Cells. The waste heat would come in handy and the fairly pure CO2 could feed back into ISRU. Reactors would be better for cranking out LOX and Methane 24/7 than Solar.

[AncientU]

...

In an ideal world SX would be able to acquire a naval reactor, which is about the right size. Unfortunately they are geared up to dump heat into an ocean of water. You could argue that a glacier is an ocean of (frozen) water, but we have no idea if it's a giant ice cube, or more like permafrosted mud.

Yes, this is about the right size*.  Naval reactors aren't made to 'dump heat into an ocean of water' though.  The reactors are closed cycle, and dump heat into a steam generator.  That system, which remains uncontaminated with radioactive products, uses a portion of its energy to turn turbo-generators, another portion to turn the shaft/propeller, and the 'waste heat' is dumped to the ocean.  Substitute more turbo-generators for the shaft/propeller, and dump 'waste heat' into closed cycle heating loops for the colony, agriculture, whatever, and you have tens or hundreds of megawatts.

The nice thing about KiloPower is it's granular. .

So are solar panels... this is a disadvantage if the grains are too small -- massively inefficient if you need tens or hundreds of megawatts.  Grain size needs to be a megawatt if it is to be useful for a settlement that is charged with making thousands of tonnes of methlox, water for hundreds and for agriculture, heat, light, etc...

IOW There are quite a lot of stakeholder in NASA would like it to succeed.

Are they making it for anyone or any planned mission?  The concept was pushed 10-15 years ago, but not sure anyone stepped up with the killer app or claimed it as a solution to their problem.

* A Naval vessel has many similarities to a settlement on Mars... hundred to few thousand people, independent of 'shore', lots of power consumed, etc.

[tesla]

I talked with a SpaceX representative a few weeks ago about this given that I am a nuclear engineer.

They have essentially no realistic concept of how to refuel on Mars. They are not really looking into nuclear given that their god and overlord is pro solar and is actively fighting the nuclear industry in the US.

Given that their concept rocket is not even on paper yet and merely a concept, with no funding for it, I understand that they dont really care about a realistic mars plan. It is essentially just a marketing thing. As far as I have been told, essentially only low/unpaid interns are given the task to look into that.

Looking at other physically and economically impossible concepts like the hyper-loop and BRF Earth to Earth, I have no doubt that they just dont care.

Edit: I also asked them about a CO rocket engine, given that it could be extracted easily from the air without water mining, I was given the answer that this was rejected by Elon's trade studies. So yeah, the god doesnt like it, so it wont be done.

-Tesla

[QuantumG]

I talked with a SpaceX representative a few weeks ago about this given that I am a nuclear engineer.

Oh yeah? Who'd ya talk to?

They have essentially no realistic concept of how to refuel on Mars. They are not really looking into nuclear given that their god and overlord is pro solar and is actively fighting the nuclear industry in the US.

Citation needed. Last I checked Elon is pro-nuclear. Why wouldn't he be?

[tesla]

I wont tell you who I talked with. He was a propulsion engineer.

I read somewhere that Tesla, with Elon as CEO is fighting against subsidies needed for nuclear to compensate for the artificially low whole sale prices. Of course, Solar City and Tesla Powerwall wants all the subsidies in the world.

Dont get me wrong, IMO he is acting super anti nuclear. I cant find a reference sorry, I read it a while ago somewhere.

-Tesla

[QuantumG]

I wont tell you who I talked with. He was a propulsion engineer.

I read somewhere that Tesla, with Elon as CEO is fighting against subsidies needed for nuclear to compensate for the artificially low whole sale prices. Of course, Solar City and Tesla Powerwall wants all the subsidies in the world.

Dont get me wrong, IMO he is acting super anti nuclear. I cant find a reference sorry, I read it a while ago somewhere.

This is a very non-scientific way to approach the world. Do your research, validate your sources and don't propagate rumours.

[envy887]

I wont tell you who I talked with. He was a propulsion engineer.

I read somewhere that Tesla, with Elon as CEO is fighting against subsidies needed for nuclear to compensate for the artificially low whole sale prices. Of course, Solar City and Tesla Powerwall wants all the subsidies in the world.

Dont get me wrong, IMO he is acting super anti nuclear. I cant find a reference sorry, I read it a while ago somewhere.

-Tesla

Maybe you should cite some actual sources, instead of spouting stuff you maybe read about somewher sometime.


Here is what Tom Mueller, THE SpaceX propulsion engineer had to say on the topic:

To get one ship back, you need about eight football fields worth of solar cells on Mars. And you have to keep the dust off them. Um; so that’s tricky. It’s much better to use nuclear, fission reactor, it gets, you know, more compact; you actually get more; you get more power out per pound of reactor than you do out of solar cells, so it’s more mass-efficient. So if you’re taking it to Mars, it’s more efficient to ship reactors than it is to ship solar; it’s just that nobody’s really developed a space reactor yet. We’re working with NASA on that, and hopefully they’ll get funding to develop that. They’ve got a program called kilopower going that’s like, ten thousand watts, a 10 kilowatt reactor. We need a megawatt, but you know, you need to start somewhere.
Eventually, the right way to have power on Mars is fission, but initially, it’ll probably be solar. But in order to get the rockets back, we need a lot of power there to make propellant.

https://zlsadesign.com/post/tom-mueller-interview-2017-05-02-transcription/

Also Gwynne Shotwell, SpaceX COO, via notes from on reddit:

Initially, Elon was not sold on nuclear propulsion - his position may have changed somewhat. SpaceX is looking at nuclear power sources (not necessarily propulsion).

https://www.reddit.com/r/spacex/comments/6ix76m/interview_with_gwynne_shotwell_on_the_space_show/

[tesla]

I wont tell you who I talked with. He was a propulsion engineer.

I read somewhere that Tesla, with Elon as CEO is fighting against subsidies needed for nuclear to compensate for the artificially low whole sale prices. Of course, Solar City and Tesla Powerwall wants all the subsidies in the world.

Dont get me wrong, IMO he is acting super anti nuclear. I cant find a reference sorry, I read it a while ago somewhere.


-Tesla

Maybe you should cite some actual sources, instead of spouting stuff you maybe read about somewher sometime.


Here is what Tom Mueller, THE SpaceX propulsion engineer had to say on the topic:

To get one ship back, you need about eight football fields worth of solar cells on Mars. And you have to keep the dust off them. Um; so that’s tricky. It’s much better to use nuclear, fission reactor, it gets, you know, more compact; you actually get more; you get more power out per pound of reactor than you do out of solar cells, so it’s more mass-efficient. So if you’re taking it to Mars, it’s more efficient to ship reactors than it is to ship solar; it’s just that nobody’s really developed a space reactor yet. We’re working with NASA on that, and hopefully they’ll get funding to develop that. They’ve got a program called kilopower going that’s like, ten thousand watts, a 10 kilowatt reactor. We need a megawatt, but you know, you need to start somewhere.
Eventually, the right way to have power on Mars is fission, but initially, it’ll probably be solar. But in order to get the rockets back, we need a lot of power there to make propellant.

https://zlsadesign.com/post/tom-mueller-interview-2017-05-02-transcription/

Also Gwynne Shotwell, SpaceX COO, via notes from on reddit:

Initially, Elon was not sold on nuclear propulsion - his position may have changed somewhat. SpaceX is looking at nuclear power sources (not necessarily propulsion).

https://www.reddit.com/r/spacex/comments/6ix76m/interview_with_gwynne_shotwell_on_the_space_show/

I am aware of those comments. However, I have the impression that they are not seriously looking into nuclear given my sources. I just wanted to share this bit of info. I cant and wont say more. Feel free to disregard my comments.

Edit, I am sorry if I upset someone. This forum is supposed to be a joy. What I am saying is dont bet on SpaceX. NASA is our biggest hope for a manned mars mission still, IMO.

-Tesla

[QuantumG]

I cant and wont say more. Feel free to disregard my comments.

You've already said too much. You're an anonymous name on a forum, not a respected journalist for a renowned newspaper - you don't get to have anonymous sources.

[deruch]

They have essentially no realistic concept of how to refuel on Mars. They are not really looking into nuclear given that their god and overlord is pro solar and is actively fighting the nuclear industry in the US.

Firstly, I reject the premise unless I see some citations or direct quotes to support the idea Elon is "actively fighting the nuclear industry."  But more importantly, there is a clear failure of logic in your statement regardless of whether the underlying premise is actually true or not.  Even if Elon thought nuclear power was a terrible idea for terrestrial power production, that has nothing to do with power generation on Mars.  Especially when you consider that the benefits of solar on Earth are lessened on Mars due to reduced insolation.  If you know anything about SpaceX's development it should be that they invariably pivot to what works and what they think will get them to Mars faster.  IMO, there's very, very good arguments for why nuclear power will have to be the main power source for the style of Mars missions Elon and SpaceX are proposing.  That being the case, I can't at all see some hypothetical (and irrelevant) ideological position dictating how they design such missions.  Especially when virtually every argument against the wider adoption of nuclear power has almost no overlap with conditions on early to medium Mars missions.

[BrightLight]

There is an L2 thread on the Kilopowr program at:
 NASASpaceFlight.com Forum » NASASpaceflight L2 Subscription Sections » L2 Orion and Future Spacecraft »    Nuclear Power for Space Applications

There are limits to the output of the Kilopower reactor designs using HEU and are well under 1mW and NASA Glenn is funding 10kW systems. Frankly, the fundamental limitation for these reactors right now is the ability to test and validate full-up systems at the Nevada Test Site (NNTS) and not launch vehicle pedigree.
"The study concluded that both the in situ resource utilization (ISRU) and crew phases of the early Mars missions were easily achieved with several 10-kWe Kilopower reactors. The Kilopower-based system won the mass and power trades for the crewed missions by a factor or two, even at solar favorable sites, which provides additional support for nuclear systems when moving further from the equator." From:
NASA's Kilopower Reactor Development and the Path to Higher Power Missions Technical Report · November 2017
DOI: 10.13140/RG.2.2.32371.22565

[AncientU]

SpaceX doesn't have the motivation to develop nuclear power... too regulated and too unpopular among the low-tech masses -- a significant majority of the US population.  If NASA has a program that can be leveraged, then it might be a possibility using NASA's good will as a cover.  Kilo-power is only a baby step along that road and they are pursuing it even so.

As discussed above, megawatts are needed to get started. Tens to hundreds of megawatts eventually.
Refueling is a cake walk compared to getting appropriately sized systems developed and made available for space use.

From my own nuclear background, water-cooled reactors are the simplest and most proven technology. It isn't some fancy, high tech solution that is needed, just a way to smuggle a few naval reactors off planet.  With appropriate approvals, of course.

[Jcc]

Ok, so if SpaceX is "looking into nuclear power" where are they looking? they obviously are not certified to do nuclear research internally ( with actual nuclear materials), so they could be talking with commercial companies or universities, or government.

The only government would be the US Government, specifically NASA and/or DOE. I am pretty sure DOD would be excluded, as would any foreign defense related technology. Commercial companies could include foreign ones, as well as US, but what company is potentially working on space-qualified nuclear? Universities have lots of ideas, but not the resources needed to develop them unless government pays.

Bottom line is that NASA Kilopower may be the only place they can look at present. Where else?

[Nomadd]

I read somewhere that Tesla, with Elon as CEO is fighting against subsidies needed for nuclear to compensate for the artificially low whole sale prices. Of course, Solar City and Tesla Powerwall wants all the subsidies in the world.

Dont get me wrong, IMO he is acting super anti nuclear. I cant find a reference sorry, I read it a while ago somewhere.

-Tesla

Come on you guys. He cited the unimpeachable source of "I read it somewhere". Admit defeat and move on.