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> Not sure why SpaceX haven't invested in it yet > an a air-hydrogen mix breathing-rocket hybrid design Tough to use a breathing rocket anywhere but Earth. An
by mabbo 6y ago
> Not sure why SpaceX haven't invested in it yet
> an a air-hydrogen mix breathing-rocket hybrid design
Tough to use a breathing rocket anywhere but Earth. And SpaceX's goal is to use this to land on the Moon, Mars, everywhere.
- Ajedi32 6y agoThat's true for Starship (the second stage) but AFAIK Super Heavy (the first stage) will only ever be used on Earth. Seems like an air-breathing rocket engine could potentially be good for that use-case.
- shdh 6y agoThen you have to introduce another system (SABRE) and integrate it with your system instead of just using the same Raptor engines being used in the second stage vehicle.
- yazaddaruvala 6y agoOne benefit of Raptor is that its designed to be mass produced. Achieving cost efficiencies with scale. Adding another engine means, one more production line each with less production volume (i.e. less efficiency of scale).
- simonh 6y agoAir breathing engines don't work well with the flight profile of vertical launch systems. Sabre wont develop near enough thrust to get a Super Heavy + Starship stack off the ground.