Re:SpaceX SN9 Explodes on Landing
by HarryHirsch on Tuesday February 02, 2021 @09:36PM
(#26009917)
Today's crash was due to failure of one engine to restart. Briz and Fregat Russian upper stages are routinely restarted, with ~ 98 % success, same with Ariane EPS and Chinese Yuanzheng. It's doable, just not for Space-X.
You realize the Raptor engine is different from the Merlin used in Falcon rockets, right?
You're comparing a prototype against decades-old, non-reusable rockets.
Briz and Fregat start much smaller - 20 kN - engines with no time constraints, while Starship re-lights 2200 kN engine and rocket immediately does rotation by 90+ degrees, and time is of essence.
Re:SpaceX SN9 Explodes on Landing
by HarryHirsch on Wednesday February 03, 2021 @01:18AM
(#26011108)
Where do thrust and chamber pressure even come into the equation? It's not that the engine exploded, the thing failed to ignite.
> Where do thrust and chamber pressure even come into the equation?
Thrust given to show difference in engine scale. Pressure isn't shown - what do you mean? :)
The point is that re-light of Briz and Fregat is very different and so hard to compare.
Anyway, landing Starship involves a bunch of things never before attempted: landing a fully-reusable second stage, landing a vehicle of this size, relighting and running engines during the belly-flop-and-flip maneuver, and flying and relighting full-flow staged-combustion engines. Probably some other firsts too.