Rocket Doc Notes for Week of August 8, 2021

Realizing Starship

Friends tipped me off about the Starship interviews on U-Tube done by the Everyday Astronaut, Tim Dodd. They are well worth your time, and you can find them at:

The main point I got from the interviews were that Starship is a work in progress and that even Elon Musk is not sure how much they are going to weigh eventually, or even what they weigh now. I found his honesty refreshing and was very impressed by the quality and speed of construction that was evident. I have years of experience witnessing other rocket programs run by both private and government entities, and believe me, there is no comparison. I am solidly behind this Space-X effort.

As far as numbers go, I heard that the Superheavy will carry approximately 3600 mT of propellants, will have an empty mass of approximately 160 mT, and an Isp vac of approximately 350 seconds. It currently has 38 Raptor1 engines installed which should give it a liftoff T/W of around 1.6. The second stage (Starship) will carry approximately 1200 mT of propellants, have an empty mass of approximately 120 mT, and an Isp vac of approximately 377 seconds.

If I plug all this into my BLAST computer model it gives me an expected payload of about 160 mT for a due East Launch into Low Earth Orbit (LEO). That tells me that they have plenty of margin for this first test flight. I wish them well, but I feel they will be lucky to get this very first bird off the ground in one piece.


Thanks for Reading,

Dana Andrews

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