Total Members Voted: 32
Voting closed: 08/25/2020 07:14 pm
I'm mostly curious to see whether the Raptor will see continued improvements over the year like the Merlin did.Let's imagine the case where they managed to uprate the chamber pressure by some absolutely crazy factor to say, 35-40 MPa. What would the most likely change to the design be? A tank stretch like on the Falcon to increase payload, or maybe reducing the number of engines to match the increased thrust, and using the extra space to increase the expansion ratio to squeeze out more Isp?
Not true, I am an advisor now. Elon and the Propulsion department are leading development of the SpaceX engines, particularly Raptor. I offer my 2 cents to help from time to time
It seems Tom Mueller is not longer a SpaceX employee:https://twitter.com/lrocket/status/1099411086711746560QuoteNot true, I am an advisor now. Elon and the Propulsion department are leading development of the SpaceX engines, particularly Raptor. I offer my 2 cents to help from time to time
Quote from: jpo234 on 02/26/2019 09:57 amIt seems Tom Mueller is not longer a SpaceX employee:https://twitter.com/lrocket/status/1099411086711746560QuoteNot true, I am an advisor now. Elon and the Propulsion department are leading development of the SpaceX engines, particularly Raptor. I offer my 2 cents to help from time to timeDo we know how long this has been? When I read that tweet I kinda had a sinking sensation.
...Tom Mueller moves to other areas that need attention.
Quote from: kevinof on 02/26/2019 10:08 am...Tom Mueller moves to other areas that need attention.Don't kid yourself. He is retiring.
Tom did an awesome job leading Merlin, Kestrel, Draco & other engine developments from start through 2014 that were critical to SpaceX’s success. Great respect & appreciation!
SpaceX Merlin architecture is simpler than staged combustion (eg SSME or RD), but it has world record for thrust/weight & thrust/cost engine. Raptor has better Isp, but I’m worried it may fall short on those two critical metrics.
This to me implies that Musk is not confident about second stage recovery. If he was, then cost/engine is not a critical metric, since all engines are recovered and re-used. The difference can be at least a factor of 2 - if you re-use a F9 booster 9 times, then you've thrown away 1/2 your engines (9 engines on the booster are recovered and re-used, and 9 MVacs are discarded). If you can really achieve full re-use, and particularly with many re-uses, then the engine cost is hardly critical.
It's interesting that Musk said in this tweet that QuoteSpaceX Merlin architecture is simpler than staged combustion (eg SSME or RD), but it has world record for thrust/weight & thrust/cost engine. Raptor has better Isp, but I’m worried it may fall short on those two critical metrics.This to me implies that Musk is not confident about second stage recovery. If he was, then cost/engine is not a critical metric, since all engines are recovered and re-used. The difference can be at least a factor of 2 - if you re-use a F9 booster 9 times, then you've thrown away 1/2 your engines (9 engines on the booster are recovered and re-used, and 9 MVacs are discarded). If you can really achieve full re-use, and particularly with many re-uses, then the engine cost is hardly critical.