Re:Musk explains why SpaceX prefers clusters of small engines
by rocqua on Thursday February 08, 2018 @05:06PM
(#16336018)
Ah I see.
Interesting about the final part of the landing occurring with a single engine even with a 3 engine landing. Makes me wonder why they don't do something like 9 engines for the breaking burn and then switch to a single engine for the landing part. It might just be that is their final plan but 3 is easier to test than 9.
Re:Musk explains why SpaceX prefers clusters of small engines
by simonh on Thursday February 08, 2018 @05:18PM
(#16336096)
It’s possible, they might gradually start using the three engines for longer, then maybe even use more engines. I doubt the last part though, the burns aren’t for very long already and I think 3 engines probably gives plenty of kick. There’s also the issue of fuel flow dynamics to the engines, but only SpaceX will have any idea about that.
They powered up the centre engine, then lit two engines either side of it, but then turned those off a few seconds before landing and still actually landed on a single engine for the last ten seconds or so. It’s hard to be sure exactly because the telephoto footage of the booster catches the start of the burns but misses the side engines shutting down. But when it pans back on to the engines, it’s clear only one of them is still lit (with one other flaring off some unspent fuel). That’s a very precise and tuneable thrust curve you wouldn’t be able to do with one bigger engine.