Demonstration Proves Nuclear Fission System Can Provide Space Exploration Power

Artist’s concept of new fission power system on the lunar surface. (Credits: NASA)

CLEVELAND (NASA PR) — NASA and the Department of Energy’s National Nuclear Security Administration (NNSA) have successfully demonstrated a new nuclear reactor power system that could enable long-duration crewed missions to the Moon, Mars and destinations beyond.

NASA announced the results of the demonstration, called the Kilopower Reactor Using Stirling Technology (KRUSTY) experiment,during a news conference Wednesday at its Glenn Research Center in Cleveland. The Kilopower experimentwas conducted at the NNSA’s Nevada National Security Site from November 2017 through March.

“Safe, efficient and plentiful energy will be the key to future robotic and human exploration,” said Jim Reuter, NASA’s acting associate administrator for the Space Technology Mission Directorate (STMD) in Washington. “I expect the Kilopower project to be an essential part of lunar and Mars power architectures as they evolve.”

​Kilopower is a small, lightweight fission power system capable of providing up to 10 kilowatts of electrical power – enough to run several average households – continuously for at least 10 years. Four Kilopower units would provide enough power to establish an outpost.

According to Marc Gibson, lead Kilopower engineer at Glenn, the pioneering power system is ideal for the Moon, where power generation from sunlight is difficult because lunar nights are equivalent to 14 days on Earth.

“Kilopower gives us the ability to do much higher power missions, and to explore the shadowed craters of the Moon,” said Gibson. “When we start sending astronauts for long stays on the Moon and to other planets, that’s going to require a new class of power that we’ve never needed before.”

Kilopower reactor (Credit: NASA)

The prototype power system uses a solid, cast uranium-235 reactor core, about the size of a paper towel roll. Passive sodium heat pipes transfer reactor heat to high-efficiency Stirling engines, which convert the heat to electricity.

According to David Poston, the chief reactor designer at NNSA’s Los Alamos National Laboratory, the purpose of the recent experiment in Nevada was two-fold: to demonstrate that the system can create electricity with fission power, and to show the system is stable and safe no matter what environment it encounters.

“We threw everything we could at this reactor, in terms of nominal and off-normal operating scenarios and KRUSTY passed with flying colors,” said Poston.

The Kilopower team conducted the experiment in four phases. The first two phases, conducted without power, confirmed that each component of the system behaved as expected. During the third phase, the team increased power to heat the core incrementally before moving on to the final phase. The experiment culminated with a 28-hour, full-power test that simulated a mission, including reactor startup, ramp to full power, steady operation and shutdown.

Throughout the experiment, the team simulated power reduction, failed engines and failed heat pipes, showing that the system could continue to operate and successfully handle multiple failures.

“We put the system through its paces,” said Gibson. “We understand the reactor very well, and this test proved that the system works the way we designed it to work. No matter what environment we expose it to, the reactor performs very well.”

The Kilopower project is developing mission concepts and performing additional risk reduction activities to prepare for a possible future flight demonstration. The project will remain a part of the STMD’s Game Changing Development program with the goal of transitioning to the Technology Demonstration Mission program in Fiscal Year 2020.

Such a demonstration could pave the way for future Kilopower systems that power human outposts on the Moon and Mars, including missions that rely on In-situ Resource Utilizationto produce local propellants and other materials.

The Kilopower project is led by Glenn, in partnership with NASA’s Marshall Space Flight Center in Huntsville, Alabama,and NNSA, including its Los Alamos National Laboratory, Nevada National Security Site and Y-12 National Security Complex.

For more information about the Kilopower project, including images and video, visit:

https://www.nasa.gov/directorates/spacetech/kilopower

For more information about NASA’s investments in space technology, visit:

https://www.nasa.gov/spacetech

  • Robert G. Oler

    we could be doing this instead of SLS…and A FH could take the experiment and some payload to the Moon.

  • Steve Ksiazek

    It will be quite a long time until NASA trusts FH to carry nuclear material. FH will be retired before it gets enough flights to reach that certification.

  • passinglurker

    This is a power source not an engine I don’t see how this would enable FH to carry a BEO space craft to the moon. Until we have BFR, another vehicle or architecture that can do at least 25tons to TLI, or a lighter manned craft with 3 weeks of life support with over 400 m/s dv we’ll be unfortunately stuck with sls till the srb casing stock pile runs out. (So about em-9 iirc)

    That is of course unless we abandon leaving leo until one of the sls alternatives comes to fruition.

  • passinglurker

    So is this enriched uranium or low enriched uranium? Cause I don’t think you’ll realistically get the weapons grade stuff off the ground.

  • Paul_Scutts

    The reactor could/would be launched “dry” and the Uranium fuel could/would be launched on a Falcon 9 or an Atlas V. Either way, Steve, much cheaper than the billions of dollars that have been and continue to be wasted upon the “obsolete” and cost unsustainable SLS. Regards, Paul.

  • Vladislaw

    I believe Robert understands that. I believe he means use a FH to launch one to Luna for on the ground testing.

  • passinglurker

    To what end without a way to ultimately get people to the moon?

  • Vladislaw

    I looked at the NASA site and could not find any numbers on it size or weight… wonder how it can be configured… safe for use on the ISS? or a spacecraft?

  • Vladislaw

    test it … let if run for a year or two .. people will be going there and it woudl be nice if it was already tested on Luna and READY for people

  • voronwae

    Three times as long before SLS should reach that level of trust…oh, wait, never mind.

  • Andrew_M_Swallow

    This is a 1 kW prototype. The next version will be built for use in space. That is the version whose size and weight matters.

  • Steve Ksiazek

    Just go take a quick peek at NASA’s certification requirements for Nuclear material. And this was for deep space exploration missions where the plutonium was well encased and would provide no risk to anyone on the ground if there was an accident. Now tell me that SpaceX will ever get to the point of launching the same FH configuration that many times before it’s already scheduled retirement. Don’t confuse the issue with your jealousy of the SLS program.

    Besides, the SLS doesn’t compete for NLS launch contracts, so it doesn’t need to play by the same rules as commercial launch providers.

  • Kirk

    Not sure about this prototype, but according the this 2016 Kilopower overview, the 10 kW(electric) model masses 1800 kg.

    https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20160012354.pdf

  • passinglurker

    That’s fair but it would take more than a few years to spool up a means to take people there when it’s ready if the commercial options don’t work as well or as fast as we are all banking on

  • Kirk

    To put that 5.5 W/kg in perspective, VASIMR’s “Mars in 39 days” requires a magical 1000 W/kg power source.

  • Michael Halpern

    Who would be jealous of the SLS program, its something to pity, not envy

  • Andrew Tubbiolo

    Space nuclear power is probably going to be the first major space technology that private industry pioneers. It’s probably a matter of a few decades, but in the long term, it’s just a matter of time. We’re far enough removed from WWII and the burlesque nuclear arsenals of the Cold War, I think people who are children today will have a more balanced view of the matter. Not to mention the extreme need that will be felt by pioneers.

  • Jeff2Space

    If today’s safety managers time traveled back to the 1960s, we’d never have landed astronauts on the moon during Apollo/Saturn V because none of that hardware could have met today’s safety rules.

    We’re getting way too conservative with today’s safety rules, IMHO. We’re not “boldly going” anywhere right now. 😛

  • Michael Halpern

    No that’s Solar way less red tape

  • windbourne

    I think his point is quit wasting more of the $32B that we have already spent on SLS and throw it at this and FH. Personally, I agree with him on that.

    It would be fairly simple to get 25 tonnes to TLI.
    FH can put 50-70 tonnes into LEO.
    This should include a lander with fuel for putting on the lunar surface.

    From there, a tug from a second FH is brought up and that can haul the previous load to TLI. And yes, it would cost a fraction of what SLS will.

  • windbourne

    robotics. If we are going there, the sooner that we can get power and robotics on the moon, the sooner that we can go there.

  • windbourne

    why? This is U-235. Besides, if they do not trust FH, then send it all up, EXCEPT launch the U-235 on atlas or delta.

  • Vladislaw

    Thanks for the heads up. only two tons.. that is really manageable then .. thought it was going to be a lot heavier.

  • windbourne

    What is interesting is that FH can send more than 16 tonnes to mars.
    I would guess that means around 20 tonnes to the moon (just a swag).
    If so, then it should be easy to send 1 of these along with a lander, all in 1 shot.
    And it should be fairly easy to encase the U-235 such that it would be safe even if FH was lost.

  • windbourne

    u-235. I’m sure that it is low enriched, otherwise, it would get too hot.

  • Vladislaw

    Exactly what I was thinking … Blue Origin’s blue moon is, I believe, 10 tons .. that could land one also. I do not believe spacex is going to bother with a lander for the FH. unless they bid on these future landers that NASA is funding.

  • Tom Billings

    Passing, …you are already leaning into Senator Shelby’s idea, that only government work is reliably going to happen. In fact, the reason it is commercial landers are being talked about is that few sane people in Washington D.C. believe that the Cost+ Congressional Contractor’s Club will *ever* produce hardware for regular and sustained human spaceflight, because that would include the risk of embarrassing their Patron, the Chair of the Senate Appropriations Committee, by an inflight failure.

  • Michael Halpern

    Saturn V/ Apollo was what they could manage with available technology and a reason for urgency, CCP has less reason for urgency and far better tech and understanding,

  • passinglurker

    I suppose you are right given the trend so far one shouldn’t simply assume sls and Orion will fly at any price.

  • passinglurker

    Falcon heavy can’t structurally support that much payload it’s its sport is javelin throwing not the Scottish log toss. It’s almost more viable to give lop-g a big docking node and spam 1 man dragons at DRO if we want to talk kludgy architecture.

  • Steve Ksiazek

    The prototype isn’t going to be ready until mid 2020’s. Musk will have cancelled both the F9, FH, and maybe even the BFR by then, and will be thinking about some other launcher. As long as people are afraid that some piece of space junk will fall on their head, they will have concerns about launching anything radioactive.

  • Andrew Tubbiolo

    Solar will go a long way, but there’s nothing like having a few megawatts that are always there. Once the chains of dependence start to get chipped away, I think the draw to nuclear power will be irresistible.

  • Michael Halpern

    that implies refining the material in space and thats a whole can of worms in itself

  • windbourne

    Would like to us bring a few of these to Antarctica bases, esp. Amundsen-scott base. This would stop the polluting of the pole, which is worse than the co2.

  • windbourne

    Considering that we continue to launch sats with nuke material on it, and we cases for these that could survive the worst explosion going, it will just be another cargo.

    As to those that are irrational and afraid of a safe cargo, well, tough.

  • Andrew Tubbiolo

    It won’t take long for someone like me who understand the importance of having the ability to mine, mill, smelt, metals and make machine tools you own and have control over. Or if machine tools are truly overlooked, the folks who make feedstock for 3d printers will know how to extract other heavy metals. Don’t forget uranium was a waste ore in Swedish silver mines. It’s out there, and future industrial engineers will know the importance of it. A future version of this guy is going to have a lifetime of fun. Too bad I’m too old to miss out.

  • Michael Halpern

    its not the capability its the Politics, OST bans WMDs in space, a nuclear centrifuge in space has the potential to MAKE WMDs in space,

  • passinglurker

    Did some reading and it seems that kilopower does indeed use the weapons grade stuff. They believe since the reactor will always be on the nose of any payload carrying it that they can just fuel it last to avoid most of the security costs…

  • redneck

    I must be missing your point here. Are you saying the FH cannot support the 50-70 ton payloads its designed for?

  • passinglurker

    Its not designed to actually lift a 64 ton payload the figure is theoretical based on vehicle performance, dry mass, and propellant load. FH was designed for the GTO market.

  • Andrew Tubbiolo

    Alll true. But it will happen none the less, and what times they’ll be.

  • windbourne

    huh.
    So, it is capable of sending 2 ppl in a dragon around the moon, BUT, it can not send a smaller load to the moon?
    Really?

    What do you base that on?

  • passinglurker

    70 tons of lander is not a smaller load than 15 tons of dragon please tell me you just made a typo.

    Either way between the payload adapter, the strongback, the fairing dimensions, and elon knows what else it simply can’t park 64 tons in LEO like everyone naively assumes it can. It can send impressive loads to TMI, TLI, GEO, and GTO, but the LEO numbers are pure extrapolation and you all make fools of yourself everytime you all propose assembling the starship enterprise in 64ton chunks…

  • windbourne

    The one making the mistake is you.
    FH can do somewhere between 20-25 tonnes into tli, and that is what I said earlier.
    You are the 1 talking about 70 tonnes to the moon. The Google lunar prize should be able to put 2 tonnes on lunar surface, and still do less than 20 tonnes total weight.

  • passinglurker

    It would be fairly simple to get 25 tonnes to TLI.
    FH can put 50-70 tonnes into LEO.
    This should include a lander with fuel for putting on the lunar surface.

    From there, a tug from a second FH is brought up and that can haul the previous load to TLI. And yes, it would cost a fraction of what SLS will.

    What you described here is not a vanilla 20 tons to TLI. You proposed a distributed launch wrongly assuming that FH can park a payload greater than 50tons in LEO to be tugged around later.

  • Michael Halpern

    Eventually sure but there’s also beamed power

  • Steve Ksiazek

    Well, we launch spacecraft headed for deep space, not Earth-bound satellites, with nuclear material, but you are correct. We are too afraid of the N word. But useful applications of nuclear power ended under the term of the one president that was actually a nuclear engineer.

    And it appears that this particular design comes with some assembly required. I’m not sure how you would launch this thing to the surface, and then have it robotically assembled.

  • Paul451

    launching anything radioactive

    Fission fuel isn’t particularly radioactive until after the reactor has been turned on. Transporting fresh fuel rods doesn’t even require regulatory approval.

    Kilopower is not an RTG or RHU. Nor will it be operational during launch.

  • Paul451

    between the payload adapter, the strongback, the fairing dimensions, and elon knows what else it simply can’t park 64 tons in LEO

    And how much do you think it would cost SpaceX to modify those items? Given that the entire cost of FH was about half a billion? [That’s around 84 days of SLS’s current funding levels (not including Orion.)]

  • passinglurker

    Depends on if there is a long term market for it spacex is only talking stretched stages and bigger fairings because of the military market for example. They aren’t going to distract from bfr to develop or maintain a niche capability without a guarantee. Even then the more fh deviates from f9 the less viable it becomes the only thing that stops it from turning into sls2 is the parts commonality with a frequent flyer.