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> We had rockets that landed with Apollo Correction: We had rockets that could land on the moon. There was no orbital-class rocket that could launch from Earth
by DarmokJalad1701 6y ago
> We had rockets that landed with Apollo
Correction: We had rockets that could land on the moon. There was no orbital-class rocket that could launch from Earth and land back at launch site (or further downrange). The difference in gravity + lack of atmosphere is a big factor.
It is like saying that the Apollo ascent module could get to orbit and therefore we can clearly make practical SSTO vehicles.
> We had rockets that were reused with the shuttle.
If you consider throwing away the massive external tank and external SRBs (without which it couldn't fly) and completely re-building the three engines after every flight.
- Dylan16807 6y ago> It is like saying that the Apollo ascent module could get to orbit and therefore we can clearly make practical SSTO vehicles. If we didn't have to worry about fuel, we could. "put in enough fuel so it can land" is not a hard problem to solve with earth rockets, it just costs payload. > completely re-building the three engines after every flight It's complicated but the level of rebuilding was driven more by very high standards than it actually being necessary to make it launchable.
- DarmokJalad1701 6y ago> "put in enough fuel so it can land" is not a hard problem to solve with earth rockets, it just costs payload. I am pretty sure that the convex optimization algorithms used by SpaceX's landing systems are a very recent invention (http://larsblackmore.com/publications.htm http://larsblackmore.com/publications.htm). As for worrying about fuel, what's the point of a rocket if it cannot take any payload?