I’ve heard numbers such as $200/kg to LEO for Starship. I’m trying to understand this.
I figure that the Falcon Heavy is already about 96.5% reusable (at least 27 of 28 engines are reused). Based on the recent Roman telescope deal ($255M), Falcon Heavy costs $4000/kg.
How is Starship, which is basically only 3.5% “more reusable”, going to cost 20X less? Is methane massively better than RP5? Is stainless steel way better than aluminum? Is it because it’s taller? Fatter? Is it the tower catch? Is it because the booster returns to the launch pad instead of landing on a drone ship?
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You cant count reusability costs like that.
A rocket is more than the engine it is a whole second stage that is expended. Even if an engine is resued there is maintance need on it and that can differ between engine models.
Even if you just look at the engine is 1 engine expended per flight. So if you do two flights you have expended 2 of 29 engines, after three flights it is 3 of 30.
The number you use for Falcon Heavy assumes all three cores land and can be reused. Space X has had a problem with center stage recovery because it travels faster than the Falcon 9 first stage. There has been 3 flight of the system and only one center core manage a landing. The stage that manage the landing was lost during the recovery operation. It was if I remember correctly because of bad weather, the center stage land farther out than the sea so there is a higher risk during recovery.
So the reusability in engine Space X has managed for the Falcon 9 is 18 of 29.
Reusability does not mean no maintenance is done. The engine needs to be checked between flights. The move from RP1 (refined jet fuel) in the Merlin engine to methane in the Raptor engine will likely result in a lot less fouling so less maintenance is needed.
I suspect the number $200/kg to LEO for Starship is a number for cost for Space X if everything works as they hope. That will no be what you sell a launch for you like to make money. Space X did talk about Falcon 9 launch costs would drop below $10 million but they are around $67 million today. Part of that is too optimistic a prediction.
Another part is the cost of something primary depends on what the customers are prepared to pay and what competitors chare for a alternative. So Space X is like other companies will not sell their product too cheap that will price it to optimise its profit. So even if Space X manage $200/kg they will charge more because they can.
If you look at extimation that likely are closer to what the cost will be if Starship works are around $1,500/kg to $2,500/kg to LEO. A lower cost than that will just reduce your own profit.
https://arstechnica.com/science/2022/05/rocket-report-meet-the-gravity-1-rocket-will-starship-really-cut-launch-costs/3/
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