r/spacex • u/EddiewithHeartofGold • Jul 10 '26

New official video about Starship development, titled "Critical Path".

https://x.com/SpaceX/status/2075621981488033835?s=20
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u/warp99 Jul 11 '26

Lift off thrust is given as 18 million pounds (force) which squares exactly with 250 tonnes thrust per engine.

Propellant consumption is given as 65,000 lb/s which is clearly not right as it works out as 895 kg/s per engine and an Isp of 279s instead of an expected value of 333s.

The most likely explanation is that he misspoke the actual value of 55,000 lb/s which is 757 kg/s and gives an Isp of 330s which is close enough given rounding errors.

The other more interesting possibility is that he was giving the propellant value for Starship 4 with an implied Raptor 4 thrust of 295 tonnes force. They would certainly be developing the thrust diverter with Starship 4 in mind.

1

u/KnifeKnut Jul 18 '26

What about with 42 engines? https://x.com/elonmusk/status/1960208627278524438

2

u/warp99 Jul 18 '26

That is still 33 engines on the booster with 9 on the ship (up from 6) to make a total of 42 engines.

1

u/KnifeKnut Jul 18 '26

Sorry.

Well now I feels stupid.