I criticized this post at the time, but Can was right. This is actually deep insight into Starship from 6 months ago, and follows exactly how SpaceX optimized Falcon Heavy (which was not the right architecture, but still useful). They will find the maximum Booster can tolerate.
Get ready for some Starship rambling
One interesting thing about Starship I noticed is that they’re clearly aiming for a higher separation velocity, hence the heat shield the booster has on its aft
Booster has been traditionally separating at 1400-50m/s, which is, horribly inefficient, and a death warrant for Ship’s PTO, and not to mention it’s worse than Falcon 9 RTLS
What I think will happen is they’ll gun for 1600-50m/s for Flight 12, and until the booster manages to splashdown successfully they’ll keep doing that, and after that they’ll do 2-3 more flights at a 1600-50m/s separation
But after that it’s gonna get wild.
What they might do is take a reused booster and have it do 1800-50m/s separation this time: aiming splashdown again
This will reduce the work that is required to be done by Ship by ~200m/s
If that works, they’ll adopt that new flight profile, doing a few catches by separating at 1800-50m/s, oh and by then, the ship is already orbital:
And everytime they increase the separation velocity by 200m/s the Starlink count to orbit on a single launch will incrementally be increasing
1600 -> 1800 -> 2000 -> 2200! -> 2400!!!
I remember reading somewhere that SpaceX’s ultimate goal in Starship’s flight philosophy is that the end goal is reaching a 2400m/s separation, this is plausible because of the heat shield and all
Though, 2400m/s would be essentially for empty Starships, for 100T payload carriers it may be 2200m/s, for Tanker/Depots it might be 2000m/s, the second stage just gets really heavy, but it’s better than Falcon 9, so I ain’t complaining
Every time the separation velocity increases by ~12%, you may ask; why doesn’t they just go for 2400m/s straight away? or decrease the 200m/s jump count by doing 400m/s or whatever?
Simply, every time tou add velocity to a system the kinetic energy increases by it’s square, in this case, every time the velocity increases by 12%, kinetic energy increases by 27%
From 1400 -> 2400 its a 71% jump velocity-wise
If we’re taling kinetic energy however, it’s a whopping 194% !!!
This is why I think they’ll go staggered this way, hence, having to expend boosters from time to time
And who knows, maybe Starship has a limit at like 2000m/s that warrants design alterations to maximize PTO
We’ll have to wait and see.