Stories
Slash Boxes
Comments

SoylentNews is people

posted by Fnord666 on Friday December 01 2017, @07:24AM   Printer-friendly
from the stirling,-not-sterling dept.

A NASA project will test a small nuclear fission power system that could provide kilowatts or megawatts of power for space missions:

In preparing for possible missions to the Red Planet in the near future, NASA's Space Technology Mission Directorate (STMD) has been given the go-ahead to test a small nuclear reactor that could one day run equipment on the Martian surface.

The Kilopower project[PDF] is working to advance a design for a compact, low-cost, and scalable nuclear fission power system for missions that require lots of power, such as a human mission to Mars. The technology uses a fission reactor with a uranium-235 reactor core to generate heat, which is then transferred via passive sodium heat pipes to Stirling engines. Those engines use that heat to create pressure, which moves a piston – much as old coal-powered ships used steam pressure to run their pistons. When coupled to an alternator, the Stirling engine produces electricity.

"What we are striving to do is give space missions an option beyond RTGs [radioisotope thermoelectric generators], which generally provide a couple hundred watts or so," Lee Mason, STMD's principal technologist for Power and Energy Storage at NASA Headquarters in Washington, D.C., said in a NASA news release. "The big difference between all the great things we've done on Mars, and what we would need to do for a human mission to that planet, is power."

Mason said the new technology could provide kilowatts of power and even be upgraded to provide hundreds of kilowatts or even megawatts of power. "We call it the Kilopower project because it gives us a near-term option to provide kilowatts for missions that previously were constrained to use less," Mason said. "But first things first, and our test program is the way to get started."

Stirling engine.

Also at World Nuclear News.


Original Submission

 
This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
  • (Score: 4, Insightful) by bradley13 on Friday December 01 2017, @08:19AM (10 children)

    by bradley13 (3053) on Friday December 01 2017, @08:19AM (#603832) Homepage Journal

    The problem with this concept: it is mechanical. A mechanical system just seems far too unreliable to send into space, land in foreign environments where you will have dust, wild temperature variations, and other problems. It seems like there must be a better way to turn large quantities of heat directly into electricity. Heat produces radiation. Solar cells turn radiation into electricity. Is it not possible to create cells that work from infrared?

    Or maybe capture the neutrons from the nuclear reaction, and put them on tiny bicycles?

    --
    Everyone is somebody else's weirdo.
    Starting Score:    1  point
    Moderation   +2  
       Insightful=1, Interesting=1, Total=2
    Extra 'Insightful' Modifier   0  
    Karma-Bonus Modifier   +1  

    Total Score:   4  
  • (Score: 5, Interesting) by Aiwendil on Friday December 01 2017, @09:15AM

    by Aiwendil (531) on Friday December 01 2017, @09:15AM (#603842) Journal

    Toss the entire package into an hermetically closed system (makes it easier to deal with regulations that way, as well as shipping compact stirling engines enclosed are pretty run-off-the-mill these days for non-sheltered installations) and the issue of dust disappears.

    For longevity the stirling engine is impressive - you could easily make one that lasts decades (even easier if in a hermetically sealed enclosure).

    And since humany have experience in landing mechincal stuff on celestial bodies (despite an annoying gap between the mid-70s to the mid-90s) I would be more surprised if this stuff failed in the first decades than if it didn't.

    (And yes, there are ways to turn heat into electricity - but for the compromise between longevity, cost, weight, size and ease of build the stirling engine is hard to beat. Oh also, solar kinda sucks more the further away you get from the sun (earth happens to about as far away as when solar makes sense) - and the space programmes might want to explore Mars and not having to shut down each night when on a planet)

  • (Score: 2) by Geezer on Friday December 01 2017, @09:51AM

    by Geezer (511) on Friday December 01 2017, @09:51AM (#603846)

    I was going to say, even with the most modern methods of friction reduction, reciprocating machinery is still subject to inefficiencies due to too much moving mass and motive power being applied during only 50% of each rotation. Flywheels are kind of clunky, especially with variable power application causing vector inertial stresses on the machine.

    Granted a Stirling engine is simpler than a steam generation system, which is better suited to a water-depleted Martian environment, and maybe NASA sees dust as degrading PV panel or focused-mirror solar Stirling efficiency as a major obstacle.

    With cargo transportation to Mars being a big issue, a means of 3D-printing repair parts from locally-available materials to repair the inevitable breakdowns would seem to be essential.

  • (Score: 5, Informative) by c0lo on Friday December 01 2017, @12:50PM

    by c0lo (156) Subscriber Badge on Friday December 01 2017, @12:50PM (#603871) Journal

    A mechanical system just seems far too unreliable to send into space, land in foreign environments where you will have dust, wild temperature variations, and other problems.

    4 words: Free piston Stirling engine [wikipedia.org] - all the moving parts are enclosed hermetically in the cylinder.

    Old designs from NASA [nasa.gov] - 55% Carnot efficiency
    See here some explanations [youtube.com]

    --
    https://www.youtube.com/watch?v=aoFiw2jMy-0 https://soylentnews.org/~MichaelDavidCrawford
  • (Score: 3, Interesting) by crafoo on Friday December 01 2017, @01:12PM

    by crafoo (6639) on Friday December 01 2017, @01:12PM (#603879)

    I don't think photovoltaic panels are necessarily more reliable or have longer useful lifespans than a well-designed and built mechanical system. I think your perception of mechanical systems is common, but is informed by cheap designed-to-fail trash that is common in our consumer world. There are many high-usage mechanical systems that last 20 years or more without maintenance or repair.

    Also a photovoltaic to transfer heat from a radioactive core would probably be massively inefficient.

  • (Score: 2) by DannyB on Friday December 01 2017, @02:28PM (4 children)

    by DannyB (5839) Subscriber Badge on Friday December 01 2017, @02:28PM (#603893) Journal

    I also came to complain about it being mechanical.

    Aside from the unreliability which you cover, I would point out the vibration induced by a piston system. Especially in space. There would be the constant vibration of pistons. This vibration would be induced throughout the entire structure. A rotating shaft with an alternator induces a rotational force upon the entire spacecraft which would require periodic compensation from thrusters.

    Sorry, due to new FCC deregulation, internet service is no longer available in your part of the city. To be notified if service becomes available in your area, enter your email address here.

    --
    People today are educated enough to repeat what they are taught but not to question what they are taught.
    • (Score: 0) by Anonymous Coward on Friday December 01 2017, @03:17PM (3 children)

      by Anonymous Coward on Friday December 01 2017, @03:17PM (#603924)

      A rotating shaft with an alternator induces a rotational force upon the entire spacecraft which would require periodic compensation from thrusters.

      I don't think thrusters are needed to compensate for unwanted rotation... you can use reaction wheels for that, right?

      • (Score: 2) by DannyB on Friday December 01 2017, @03:28PM (2 children)

        by DannyB (5839) Subscriber Badge on Friday December 01 2017, @03:28PM (#603931) Journal

        Yeah. More mechanical systems.

        --
        People today are educated enough to repeat what they are taught but not to question what they are taught.
        • (Score: 0) by Anonymous Coward on Friday December 01 2017, @04:23PM (1 child)

          by Anonymous Coward on Friday December 01 2017, @04:23PM (#603947)

          I for one look forward to our glorious mechanical future and the Victorian æsthetics it will undoubtedly renew. It's steampunk, just with nukes and no steam.

  • (Score: 1) by Muad'Dave on Friday December 01 2017, @06:07PM

    by Muad'Dave (1413) on Friday December 01 2017, @06:07PM (#603985)

    It seems like there must be a better way to turn large quantities of heat directly into electricity.

    That's the old RTG [wikipedia.org] they're trying to get away from.