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Aerospace Plasma as a Heat Shield?

  1. Oct 4, 2008 #1
    Is it possible to use plasma as a heat shield for a re-entry vehicle?

    We all know that plasma isn't very dense, but then neither is the thin upper atmosphere that causes re-entry heating in lieu of drag.

    I'd read that a simple trick used by ICBM warhead engineers, was to simply have a perforated heat shield which was also a water vessel, so that re-entry heating would make the water boil forth, emerging the holes as steam, which would then protect the heat shield itself from the atmospheric friction. This seems like an elegantly simple solution.

    But couldn't plasma also then do something similar, acting as a similar kind of buffer between the vehicle and the oncoming atmospheric gas molecules? Also, consider that a higher proportion of the upper atmosphere would be ionized anyway. This could permit the use of charge field interaction to ward off atmospheric heating.

    I'm simply suggesting this as a lightweight solution against re-entry heating.
  2. jcsd
  3. Oct 4, 2008 #2
    No, I think theres a lot of problems with that. First off, how would you generate the plasma. Second, how would you contain the plasma. And third, plasma by nature is extremely hot and would probably do more damage than good.

    The purpose of the water jacket is not use the steam itself as a barrier but to absorb heat by changing the phase of the water from liquid to vapor. Similar to the purpose of heat pipes except the water jacket isn't sealed obviously.
  4. Oct 4, 2008 #3
    Plasma doesn't have to be hot, it can just be ionized. For instance, a plasma antenna isn't hot. It doesn't have to be contained either, it can just be generated around the bottom of the craft. It can be continuously generated, even as it is swept away by the flowstream around the craft.

    Otherwise, I'm wondering if there might be a way to pattern the heat shield surface to generate lots of vortices against its surface, even in thin upper atmospheric conditions.
    Those vortices would then consist of denser air which would buffer against the oncoming thin supersonic air, to insulate against atmospheric heating.

    Usually we see space capsules as having a convex bottom, but I'm wondering what would happen if the craft had a concave bottom that curved upward/inward?
  5. Oct 4, 2008 #4


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    This sounds rather similar to an idea I had sometime ago. When a capsule enters the atmosphere, it generates plenty of plasma on its own. I was wondering if there was some way the leading edge or "belly" of such a vehicle could be magnetized. If a positive magnetic field were generated in the skin of the craft, this would repel the plasma created by the impact of that skin with the atmosphere. It seems that, with the plasma forced even a short distance away from the skin of the vehicle, heat transfer from the plasma to the skin would be greatly reduced.
  6. Oct 4, 2008 #5
    I came across some company called Electrofluid Systems which is doing research into Plasma Aerodynamics (electroaerodynamics):


    The sidebar on the page features a whole lot of different projects.
  7. Oct 5, 2008 #6
    Last edited: Oct 6, 2008
  8. Oct 6, 2008 #7
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