Viewing 9 posts - 16 through 24 (of 24 total)
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  • #11828
    DerekShannon
    Participant

    It was something called the “Advanced Propulsion Technology” program.

    #11829
    ikanreed
    Participant

    zapkitty wrote:

    Well, I suppose that’s pretty reasonable. But, for example FoFu-1 is very sensitive to disruption. Imagine if you had tin whiskers on the electrodes, even very tiny ones.

    Tin? Where would the tin come from? The electronics would have to be outside the vacuum chamber.

    And even an FF space drive will have a vacuum chamber… as the fuel pressure has to rise to several torr before you can start it.

    That it is space-based would just mean that you save on the cost and maintenance of a vacuum pump.

    A plasma window should be able to allow the beam to exit the chamber into an exhaust assembly of some kind while maintaining chamber pressure.

    Tin whiskers come from the sodder used to finish circuitry. In the absence of gravity and friction, that sodder, bearing slightly electrical charge(caused in part by the very circuits they are part of), will, atom by atom, move into long whisker shape leading to short circuits and variation in electric/magnetic fields. I’m not saying that WOULD happen in a space based FoFu, just that when alignment is so critical, it’s the kind of failing you wouldn’t want to have happen.

    #11830
    zapkitty
    Participant

    ikanreed wrote:
    Tin whiskers come from the sodder used to finish circuitry.

    Yes, it is a known issue for electronics, including spacecraft electronics.

    And it seems certain that engineering an FF unit for spacecraft use will turn up its own surprises.

    But metal whiskers would not to seem to be able to do well in an FF chamber. These are crystalline metal structures thinner than a human hair.

    The FF equivalent would be beryllium whiskers or some other chamber material – and would any such even be whisker prone? – and the concept requires a fairly static environment for the whiskers to grow large enough to be a problem….

    … and the interior of an operating FF chamber isn’t exactly a static environment 🙂

    So I’d think that if even if there were any potential whisker problems in an FF chamber they would turn out to be as much of a problem for planetside units as for spaceborne units… if…

    #11831
    wolfram
    Participant

    zapkitty wrote:

    You know what really scares me about fusion thrusters?

    Kzinti?

    You misremeber your future-history, it’s call the kzinti lesson because they learned to fear humans with fusion thrusters in orbit.

    #11832
    zapkitty
    Participant

    wolfram wrote: You misremeber your future-history…

    I was wondering if ikanreed was a Kzin 🙂

    I thought I met a Kzin once but it was just Garfield…

    #12114
    Joeviocoe
    Participant

    “It should be based on currently accepted principles of physics
    and reasonable technology extrapolation
    (no cold fusion, matter/anti-matter, P-11B, worm holes etc.)”

    This really bothers me. It either shows a complete lack of understanding about these 4 concepts… or a deliberate attempt to divert attention away from pB11 as a competitor.

    Worm Holes don’t exist naturally close enough to Earth to use them. And the very scientists who hypothesize creating artificial wormholes know that it would take more energy than our whole sun contains to produce.
    Matter/antimatter is not viable because it requires more energy to create than it would release. We cannot simply convert matter into antimatter.

    Cold Fusion does not even have a credible hypothesis. But was discredited.

    pB11 may not be a reality yet, but there is no physical law saying it can’t be done. If deuterium fuse, so can pB11. It just takes more energy.
    We already know that Boron-11 fuses…. we have done it in particle colliders. So this concept is no where near the 3 others.

    It truly seems like a deliberate attempt to divert attention away from pB11 as a competitor. They might be worried that aneutronic fusion may get the spotlight soon. And if LPP or others succeed, the funding for their project might dry up considering DPF does have space propulsion potential.

    #12130
    vansig
    Participant

    zapkitty wrote:

    You misremeber your future-history…

    I was wondering if ikanreed was a Kzin 🙂

    I thought I met a Kzin once but it was just Garfield…

    seems to me, that the closest match to Kzin we have, here, is zapkitty?

    😛

    #12169
    Ivy Matt
    Participant

    NASA has announced its 2012 NIAC Phase I and Phase II selections. John Slough’s team at MSNW LLC was selected for a NIAC Phase II award of up to $500,000 over the next two years.

    #13606
    Ivy Matt
    Participant

    NASA has announced partnerships with 12 companies “to advance concept studies and technology development projects in the areas of advanced propulsion, habitation and small satellites.” Three of those companies (including MSNW LLC) will be developing propulsion technologies:

    Selected advanced electric propulsion projects will develop propulsion technology systems in the 50- to 300-kilowatt range to meet the needs of a variety of deep space mission concepts. State-of-the-art electric propulsion technology currently employed by NASA generates less than five kilowatts, and systems being developed for the Asteroid Redirect Mission (ARM) Broad Area Announcement (BAA) are in the 40-kilowatt range.

    The three NextSTEP advanced propulsion projects, $400,000 to $3.5 million per year per award, will have no more than a three-year performance period focused on ground testing efforts. The selected companies are:

    Ad Astra Rocket Company of Webster, Texas
    Aeroject Rocketdyne Inc. of Redmond, Washington
    MSNW LLC of Redmond, Washington

    It doesn’t specify MSNW’s propulsion technology. They have publicly revealed three: the Electrodeless Lorenz Force (ELF) thruster, the Electromagnetic Plasmoid Thruster (EMPT), and the Fusion Driven Rocket (FDR). All three are field-reversed configuration (FRC) plasma technologies, but only the latter involves fusion. The Fusion Driven Rocket was funded through the NASA NIAC program, so it’s possible the NextSTEP project is a continuation of that project. However, as far as I am aware MSNW has not published “Experimental demonstration of fusion gain with inductively driven metal liners” or a similarly-titled paper, so who knows what they’re up to? The ELF thruster is supposed to be able to use the Martian atmosphere as a propellant, so it’s possible MSNW is being tapped to develop an engine for a landing vehicle, rather than a space thruster.

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