6 ms·
They've made some amazing progress! However, a landable booster can't put itself into orbit -- its engine cutoff is always well under 3000 m/s (today's was abou
by neolefty 9y ago
They've made some amazing progress! However, a landable booster can't put itself into orbit -- its engine cutoff is always well under 3000 m/s (today's was about 9800 kph according to the YouTube broadcast, or about 2700 m/s, and that was with no fuel margin left for landing), but about 7800 m/s is required for orbit.
- ChuckMcM 9y agoElon's tweet today (https://twitter.com/elonmusk/status/669132749500887040 https://twitter.com/elonmusk/status/669132749500887040) was that a booster with no payload could put itself into orbit. And that certainly supports your statement. It clearly would not be possible to launch a second stage and have the booster stage make it all the way into orbit. But it isn't as far out of whack as it might be.
- wolf550e 9y agoTsiolkovsky is very clear about the propellant mass fraction needed for single stage to orbit, and it is unachievable with current materials, i.e. you can't build a useful SSTO using Al-Li tanks. https://en.wikipedia.org/wiki/Single-stage-to-orbit#Design_challenges_inherent_in_SSTO https://en.wikipedia.org/wiki/Single-stage-to-orbit#Design_c...
- marvin 9y agoSSTO with a significant payload then, presumably.
- xorxornop 9y agoYup. Even carbon composites don't really work out (minimal payload) until the rocket is very large (see: ITS)
- Symmetry 9y agoThe first stage has a fuel mass fraction of 95.5%. Propellant densification and high thrust to weight ratio engines buy you lot. That should be enough to make orbit.