Rocket Engine Pulled from the Ocean Definitely Belonged to Apollo 11

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8 points·gullyfur··4 comments

F-1 is still the biggest chamber, by thrust. We decided to go with smaller, even though much more advanced engines; even Starship is going to use Raptors of smaller thrust per chamber. Were the questions of how to develop first stage engine answered differently in 1960-s than now? Starship is decidedly not Sea Dragon regarding first stage engine solution; will we come to bigger thrust chambers again or we see why we won't need them?

These are just my personal thoughts, but my guess would be that we don't go back to having big chambers. Having more chambers and engines theoretically provides more fault tolerance. I think one of the things that has really improved since the 1960s is how much smaller and faster a control system can be since we've got much more powerful computing.

There are good arguments for big chambers as well, so we need to consider both sides. Cooling of bigger chamber is easier, as we have the law of cubes-squares (volume growth against area growth with growth of the size). We have less parts, so less things to fail. Also potentially better mass efficiency (thrust to mass), as some elements can't be scaled proportionally to smaller sizes.

For big rockets, where such chambers would be appropriate, we don't need particularly fast control system. Saturn-V could even be flown with manual control, and astronauts were trained to do that.

Of course there are advantages with smaller chambers and smaller engines too.

Note that this is from 2013.

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