SpaceX Switching to Thin Tile Heat Shield Instead of Active Cooling

Elon Musk indicated that SpaceX will test thin ceramic tiles to protect the Super Heavy Starship from re-entry heat instead of using active transpirational cooling.

This will only need to be on 10-20% because the steel alloy could handle most of the re-entry temperatures.

The first stage super heavy booster does not require a heat shield because it only reaches mach 8 or 9.

20 thoughts on “SpaceX Switching to Thin Tile Heat Shield Instead of Active Cooling”

  1. Definitely no windows. I don’t recall Truax talking about a passenger version*.

    My conversation with Truax was circa 1989 in at his office in Carlsbad, CA when we were putting together the Launch Services Purchase Act of 1990 with Congressman Ron Packard (whose office was basically across the street coincidentally enough). I was attempting to ascertain the potential markets for large scale launch systems and Truax’s sea launched Big Dumb Booster seemed a likely candidate for a reusable system.

    Cheap access to space was on everyone’s mind since NASA’s “reusable” shuttle had come in a factor of about 100 more expensive than the sales pitch to Congress, and killed any hope of space settlement/industrialization.

    Since the sea launched BDB was to be built in a shipyard based on steel hulls, the resemblance to SpaceX’s system is obvious.

    NASA’s space shuttle had such severe operational problems with ceramic tiles between flights, the question about heat was obviously on my mind. I’m pretty sure I asked him about the heat problem with the BDB and the rotisserie response is what I got from him.

    *However, launching people during space settlement — a consequence of cheap access provided by the BDB — doesn’t require them to reenter. In that scenario, they are cargo. So we weren’t particularly interested in humans coming back.

  2. Early Disney Space Films used something like parachute harnesses with 8 suspension points, instead of rigid metal frame seats.

  3. I can’t believe Truax said that, unless he was assuming no windows. Hopefully, Bill Sprague, Truax’s VP, will see this and comment on it.

  4. Getting matching Coefficients of Thermal Expansion over a wide range of temperatures is the real issue.

  5. The Russians used super-plastic forming to wrap the leading edges of their steel airframe fighter jet wings with thin high-heat resistant titanium alloys.

  6. Crews would presumably prefer not to spin. Gimballed seats could be done, but as Asteroza commented above, that might not be practical.

    But yes, I actually prefer StarShip be made into a 2nd stage booster that can deliver a variety of 3rd stages to orbit, then separate for Earth-return. No crew or cargo on board during return, so it could indeed ‘just rotate’.

  7. You act like you’ve never heard of Robert Truax and like cargo is a minor consideration. Both lead me to believe you may not have sufficient depth to credibly comment even on passenger systems.

  8. Why rotate the outer hull when you can just rotate the entire rocket ?. No need to overcomplicate it.

  9. The only thing that could kill the buzz of flying in space would be to do it strapped down like cargo with no windows. They already said the passengers would be strapped down like in roller coasters. Now you want to take the view away because no window is going to want to be windward during reentry.
    For a purely cargo version, maybe. But now you have no “cool side” on which to put more sensitive components.

  10. My guess is that if you rotate you still get to hot and now you have to shield all the rocket not only one side including harder to shield parts like the hatch and all sides of fins.
    It would also be hard to control aerodynamically if rotating. so more control surfaces who would also need shielding.

  11. I would think the passenger version would differ from the payload launch version, but we’ll go with your objection:

    Do you have a URL showing the proposed passenger seats and their arrangement? Off-the-cuff tweets by Musk about “Magic Mountain roller coaster” is all I see.

  12. I’m sure they don’t intend to have a super hot metal hull exposed directly to the inside anywhere on the ship, so the hull must be multi-layered.

    So why not just have the outer hull rotate?

  13. I’m pretty sure Robert Truax told me the solution was rotisserie cooling. Musk must have considered that. Why was it rejected?

  14. Shuttle tiles were glued to the aluminum skin, with a flexible spacer between the skin and the ceramic tile. That’s because aluminum expands, and ceramic doesn’t The aluminum could not get very hot, so the glue wasn’t a high temp material.

    With a stainless steel skin, you can go much hotter, and thus get away with thinner heat shield tiles, but I don’t think glue would work. I suspect they will use mechanical fasteners to hold the tiles in place, in which case replacement will be much easier. This could be something like a metal clip that fits into a slot on the tile, and the other end is welded to the skin.

  15. I trust the Musk that the tiles do not need to be replaced after every flight and when they do, it will much easier then the shuttle tiles.

  16. I wonder if they could adapt a 3-D printer to coat the stainless steel directly instead of gluing tiles. Should make it cheaper to build and might increase reliability. All depends on the print material existing of course.

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