Raptor Engine at SpaceX Starhopper Launchpad

SpaceX is installing the first Raptor engine into the Starhopper. There is video and pictures of the Raptor engine beside the Starhopper. Vivian Okoy shared a tweet with a picture of the Raptor engine. The Raptor engine has nearly twice the power of the current SpaceX Merlin engine. There will be three Raptor engines used in the Starhopper test vehicle. There will be seven Raptor engines used in the Starship upper stage and there will be 31 Raptor engines in the Super Heavy booster stage. The combined Super Heavy Starship will be full reusable.
Raptor engine at the SpaceX Starhopper Launch pad. Screenshot from Spadre.com video

21 thoughts on “Raptor Engine at SpaceX Starhopper Launchpad”

  1. Technically cooled by running liquid methane through them to absorb heat but they still radiate heat. You want them far enough away so that one can explode and not take other engines out.

  2. I don’t thing the actual Space X technology would the best to be used to transport people around the world as advertised. I belive “air-breathing’ hypersonic engine aircraft” will be the best one.

  3. First stage doesn’t orbit- it boosts back and lands at the launch pad.

    The 50k number is 100% made up but that could easily be every 50 launches for the first stage.

  4. It is not just the chamber. You also have to run the turbopumps and chamber cooling at higher pressure. fuel goes through tubes in the chamber wall to keep it from melting, then later into the chamber to burn. So to increase engine pressure, you have to beef up most of the engine parts.

  5. I think the engine bells are radiatively cooled, so you can only pack them so tightly before they’d overheat.

  6. It certainly IS more complicated than that.

    For one thing, in order for the engine to actually run, you have to pump the fuel and oxidizer into the chamber against that pressure, and at a high enough rate that the burn rate sustains the pressure you’re aiming for. So the turbo pump requires more power the higher the chamber pressure, and in a non-linear way.

    For another, the higher the pressure, the better the heat transfer to the chamber walls. And the contents of the combustion chamber are easily hot enough to melt any metal, so they have to be cooled fast enough to keep them from melting, which gets harder as the pressure goes up, but also gets harder as the chamber walls get thicker. Because at those heat flow rates, even a thin bit of metal can have a significant temperature difference across it, and if even the inside layer gets hot enough to get soft, it’s all over.

    So the engines get harder to run the higher the pressure, and thicker walls is not really a solution.

    Unless you’re talking single use rockets with ablative linings, which this isn’t.

  7. Do you think it possible to just make the walls of the burn chamber thicker to take higher pressure? Or is it more complicated than that?

  8. The first Raptor engine that broke chamber pressure record on a stand got damaged in the process so this is engine #2. I wonder if they could strengthen the chamber to be able to take close to 300 bar safely.

  9. Yes, add that spaceX love to collect data, and that upper stage is close to an B52 in engine out at capacity at separation, later they are better.
    First stage 🙂
    Guess they use steel / ceramic for separation. Probably multi layers as in first in pump wall then the armor

  10. Raptor bell diameter is only 1.3 meter in comparison to 0.9m of Falcon so should be possible to tightly pack 32 of them in 9m diameter booster.

  11. I like how the entire engine has less of a footprint than the bell. Basically it means you can place them inside a kevlar enclosure and then but the enclosures next to each other. The engine has clearly been designed for the BFR.

    I’m sure that in the future BFR’s will head in to the shop for their 50,000 mile checkups and technicians will swap engines. Cool stuff.

  12. Rocket engines are incredibly simple machines at their core, but high performance liquid fuel rocket engines have a lot of fiddly bits around them.

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