The Next Generation of Heat Shield: Magnetic

Heat shields are an important part of any space vehicle that re-enters the Earth’s atmosphere. The next generation of heat shields to protect astronauts and payloads on their re-entry into the Earth’s atmosphere may use superconducting magnets to deflect the plasma that forms in front of spacecraft as they travel at high speeds in the air. The first test of such a heat shield could happen as early as ten years from now, and the basic technology is already in development.

Traditional heat shields use the process of ablation to disperse heat away from the capsule. Basically, the material that covers the outside of the capsule gets worn away as it is heated up, taking the heat with it. The space shuttle uses tough insulated tiles. A magnetic heat shield would be lighter and much easier to re-use, eliminating the cost of re-covering the outside of a craft after each entry.

A magnetic heat shield would use a superconductive magnetic coil to create a very strong magnetic field near the leading edge of the vehicle. This magnetic field would deflect the superhot plasma that forms at the extreme temperatures cause by friction near the surface of an object entering the Earth’s atmosphere. This would reduce or completely eliminate the need for insulative or ablative materials to cover the craft.

Problems with the heat shield on a spacecraft can be disastrous, even fatal; the Columbia disaster was due largely to the failure of insulative tiles on the shuttle, due to damage incurred during launch. Such a system might be more reliable and less prone to damage than current heat shield technology.

At the European air and space conference 2009 in Manchester in October, Detlev Konigorski from the private aerospace firm Astrium EADS said that with the cooperation of German aerospace center DLR and the European Space Agency, Astrium was developing a potential magnetic heat shield for testing within the next few years.

The initial test vehicle would be launched from a submarine aboard a Russian Volna rocket on a suborbital trajectory, and land in the Russian Kamchatka region. A Russian Volan escape capsule will be outfitted with the device, and the re-entry trajectory will take it up to speeds near Mach 21.

Though the scientists are currently testing the capabilities of a superconducting coil to perform this feat, there is the challenge of calculating changes to the trajectory of a test vehicle, because the air will be deflected away much more than with current heat shield technology. The ionized gases surrounding a capsule using a magnetic heat shield would also put a wrench in the current technique of using radio signals for telemetry data. Of course, there are a long list of other technical challenges to overcome before the testing will happen, so don’t expect to see the Orion crew vehicle outfitted with one!

Source: Physorg

21 Replies to “The Next Generation of Heat Shield: Magnetic”

  1. I first heard about this idea awhile back, and while I find it a fascinating and worthwhile idea, I’ve heard no mention of how they plan to power the thing. Presumably, the superconducting materials would also require a fairly complex cooling system. All together, that might eat up quite bit of weight. Would the benefits be greater than the reduced cargo capacity or increased fuel requirements?
    Anyone know how much power a shield like this would need?

  2. Two immediate reflections is on the weight (“lighter”? really?) and on safety: you would need two separate systems, as there is no other backup with a dynamic system.

    the Columbia disaster was due largely to the failure of insulative tiles

    But the synopsis of the CRS congress report says:

    “The physical cause was damage to Columbia’s left wing by a 1.7 pound piece of insulating foam that detached from the left “bipod ramp” that connects the External Tank1 to the orbiter, and struck the orbiter’s left wing 81.9 seconds after launch. The foam strike created a hole in a Reinforced Carbon-Carbon (RCC) panel on the leading edge of the wing, allowing superheated air (perhaps exceeding 5,000oF) to enter the wing during reentry. The extreme heat caused the wing to fail structurally, creating aerodynamic forces that led to the disintegration of the orbiter. (Described in detail in Chapters 2 and 3.)”

    Nothing at all about any tile damage.

    The RCC panels were, IRCC, used as leading edge wing protectors, analogous to other use as rocket cone protectors. It wasn’t the new and inventive heat protecting system that failed, it was “old reliable” that wasn’t used as earlier. (Put in the stream of foam pieces that tears of the shuttle at regular use.)

    Also, the Buran tile heat protection system was further superior to the Shuttle, withstanding another 100 K and with no tile losses whatsoever during its lone flight.

    AFAIU these tiles have never caused a flight loss. (But IIRC reportedly been close to at at least one flight.)

  3. @ Torbjorn Larsson OM

    But the RCC are some kind of tiles, too, aren’t they? 😉

    AFAIU these tiles have never caused a flight loss. (But IIRC reportedly been close to at at least one flight.)

    I remember reading an article on about a flight of Atlantis. It was the second flight after the explosion of Challenger.
    The problem was that it was a “secret” mission – even NASA had only minor contact with the astronauts and didn’t receive the pictures the astronauts took of the under-side of the shuttle during the mission (the significant loss of foam was obvious, so the inspection was performed; but not in a way as it is today). So, NASA thought that there were no problems at all, and only the astronauts knew that the heat shield was severely damaged.
    It was just luck that they made it back down to earth.

  4. The superconducting magnet should require little power provided the magnetic field is constant. Provided the magnet is kept cool enough, it requires no energy at all, and space has plenty of good vacuum and cold. Getting the magnet down to temperature on the ground is a bit trickier: you would probably cool the thing down to liquid nitrogen temperatures, then have a Peltier block followed by a magnetostrictive heat pump to get down to the really low temperatures. This won’t be very efficient but once the thing is cold, you get good vacuum automatically because any gas other than helium ought to freeze, so the heat loss ought to be pretty small.

    The bad news is the energy in the magnetic field. An 11 Tesla field has the same energy per unit volume as TNT, and no mass, so get gets dumped immediately into anything metal around it. The magnet will have large hoop stresses to contain the magnetic field, and any flaw will lead to explosive bursting. Remember the damage done to the LHC when a magnet quenched? That was a big installation on the ground with a fat shunt resistor to stop the explosive releases of energy, and it still made a fair old mess. I would have thought a plasma spike might be a better or at least safer solution – you would only turn that on on re-entry.

    I must say, this makes me a bit nervous. All the best mad scientist proposals involve space, a giant superconducting magnet, and usually a nuke of some sort. However, they are actually going to build, and they seem to have left out the nuke out, so it might actually happen. I will wait and see.

    At first, I wondered whether they really wanted to deflect the plasma. After all, that is what is slowing the craft down. Don’t you want to hold the plasma in place? After a bit of thinking, I figured it out: you want to slow down, but the heat loss becomes a problem because you are decelerating too fast. If you make the thing slip through the air better, you take longer over re-entry, stay cooler, and can use conventional aircraft alloys which are not brittle. o, deflecting the plasma is right.

  5. I am not an expert on this topic, but I have read about interest in using MHD physics to construct shields in general. This could include protection against micrometeoroids and orbital debris.

    It will be a while before these become reality. There are considerable power requirements for the superconducting coils to magnetically hold the plasma.


  6. Lawrence B. Crowell said: “It will be a while before these become reality. There are considerable power requirements for the superconducting coils to magnetically hold the plasma.”

    True, but isn’t is possible the energy of the reentry itself be utilised towards the power requirement via electrical conduction via diffusion? Surely there is enough energy to develop a sizeable current?

  7. Would a magnetic shield be able to deflect solar radiation as well as heat? – might be useful on a long trip to Mars. “shields up – red alert”!

  8. @Hon. Salacious B. Crumb. In principle the heat of re-entry could be used. However, one has to realize that to use heat energy you need a cold bath or reservoir as well. Dumping waste heat from some heat flow or heat engine is not easily arranged on board a spacecraft engulfed in hot ionized gasses during re-entry.


  9. WOW article with dirty words: plasma and magnetic field.

    And even Hon. Salacious B. Crumb talking dirty using the words “MHD physics” LOL

    Maybe they should ask Anaconda how he did it? I have no doubt that he has the perfect solution right now. He is probably z-pinching the plasma in front of the heat shield and then through berkley currents this soft woolly sheet with a nice touch of green softening the flow of plasma along the sensitive skin of the capsule. LOL

  10. OK lets use some dirty words too.

    The capsule needs to dump waste heat but if the magnetic field is so strong that the plasma never touches the capsule then the heating would be minimal.

    Also moving plasma means it generates a magnetic field so somehow we could tap into this and use it to create power for the magnetic fields.

    I am wondering if we could not create a tube that extends into the plasma in front so the plasma gets channeled through the tube and this heat could be somehow converted to electricity.

  11. It would be very interesting to modulate and rotate a large mag. field while on orbit… aligned with and/or perpendicular to the Earth’s mag. field lines.. or emitted in alternating patterns or polarity?

    Would it be even more interesting were the above spacecraft towing a conductive cable for power generation?

    Remember the melted cables/equipment on BOTH shuttle tether experiments?

    Orbiting satellite time/speed anomalies explained?

  12. If you are to put a tube that funnels plasma then you could run a turbine. So the central core of the re-entry vehicle would be a turbine and powerplant.


  13. I found a nice short analysis of the issues at hand here;

    Atti, “Preliminary Design of an Electromagnetic heat shield for a Reentry Spacecraft”

    They explain;

    “During the reentry flight the gas behind the strong shock wave is more or less ionized and has an electrical conductivity. Then, when a suitable magnetic field is applied to the conductive shock layer, the flow behind the shock can be controlled using the Lorentz force. Ions interact with a magnetic field, and therefore if the descending orbiter presents a high enough magnetic field, the hot plasma can be deflected away from the surface of the vehicle”

    Therefore it uses the Hall effect – explaining the generated current flow.

    References 4 and 5 I looked at this morning, which from the American Institute of Aeronautics and Astronautics (AIAA), which explains the concepts in detail but it is not available on-line. Typical.

    As for Olaf’s comments;.

    I’ve never had any aversion to using ‘dirty’ plasma physics and MHD physics – after all it is a legitimate for of study. The problem is the mind wipe that EVERYTHING can be explained by it and can solve issues from the micro to cosmic proportions.
    Astrophysics may have a long way to go in explaining the behaviour of phenomena, but that does not mean we have to throw it all with the bathwater – cart blanche so to speak – just because a bunch of ‘electricians’ say so.
    The thing that annoys me is they have no concept of stellar evolution – and they attempt to argue that ‘it s all wrong” (electric sun) – when they don’t have a clue how stellar evolution theory has evolved let alone the observational data supporting it. I.e. They think, as do the creationists, that the Main Sequence of stars is wrong because they believe the graphic line drawn shows evolution up the line instead of away from it. (This, by the way, tells you and EU proponent one from an astronomical / astrophysical basis. Solrey and Anaconda being the classic examples.)
    So I might be talking ‘dirty’, but unlike to nutters, it is a realistic appraisal and not based on wannabes. LOL if you must!

  14. oTay now.. The ESA is thinking about putting re-entry capacity aboard their Automated Transfer Vehicle (ATV). And Japan’s JAXA is reassessing the build of their follow-on orbital transfer vehicle, the H-2B…

    Here’s hoping this tech. demo works out in time for this feature to be included in any design review – making both vehicles reusable?

    Seems a shame to use these vehicles for trash disposal after their delivery missions to the ISS?

    Actually, I’d want them left on orbit nearby.. the number added to as resupply missions continue.. eventually they would be used to create a LUNAR orbiting space? station….?

  15. That is what I thought how it operated Hon. Salacious B. The Star Trek force field.

    The question is if we could have a big enough power source to keep this magnet for this period reliable and strong. We are only talking about a few minutes, and cooling the superconductor could already be done in space for free.

    So I was wondering if the heat itself or the streaming from the plasma next to the capsule which is a magnetic field, be reused to feed the superconductor reducing even more power needs.

    I call “plasma” the dirty words since it always triggers some EU SPAM. LOL
    They have clearly no clue what they are talking about but when the word “plasma” is used they start with their preprogrammed mantra just like the creationists. They have no clue what they are saying but the can solve every mysterie in the universe.

    The wierd thing is this is a topic they could use their superior understanding of electricity on to educate us, but of course they have no preprogrammed response for this situation.

    When I was still in school I was wondering how a Start Trek force field could between the shuttle deck and space be so flat and why people did not get sent into space when thy looked through the force field. Then I imagined to have a lasers in the doorway panels itself that would blast every oxygen atom in the doorway so it became charged and then a magnetic field also in the doorway side panels to hold it there just like a CRT TV set.

    Yes I admit all my life I have been thinking about the cool ways of using plasma and magnetic fields. LOL The Creationists, oops I mean the EU-tionists are wrong to think that we never think about these possibilities. LOL

  16. @ Aqua
    “Orbiting satellite time/speed anomalies explained?”

    That magnetic field would be detectable and will have an influence on all satellites that also orbit there. And a fast moving space craft would move sideways not speed up or speed down when moving in a magnetic field.

  17. I call “plasma” the dirty words since it always triggers some EU SPAM. LOL

    Cool!!! dirty talk

    Seems the only problem is energy storage (electrical)

    TSS-R1 proved just how much current can be draw from the Earth’s EM field. the tether can be used as both a motor and a generator.

    So it seems a magnetic shield would be kinda redundant if we do not have to re-enter the atmosphere at typical re-entry speeds, no need for ablative heat tiles either.

    Just use the KISS principle, deploy the tether collect the power (big capacitors??) boost or degrade the orbit as you choose.

    After all it is what “they” use! (minus dragging a tether)

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