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I don't mean to be evasive, but there are a couple of reasons why I'm uncomfortable answering such direct questions that may involve internal procedures: 1. I'

I don't mean to be evasive, but there are a couple of reasons why I'm uncomfortable answering such direct questions that may involve internal procedures: 1. I'm not nearly knowledgable enough about the overall refurb process to give you an in depth answer. The best answer I could probably point you towards is this article[1] quoting our President Gwynne Shotwell. It won't give you the specifics you're looking for, but it will give you an idea of the costs in relation to a new build. Seeing as labor is a fairly large cost component of the rocket overall, this gives you some idea of the potential extent of refurbishment vs building a new rocket. 2. Even if I did have the requisite knowledge to answer your question, those kinds of internal procedures aren't something I could share. My apologies. As to what breakthroughs make this sort of inspection and reuse possible, and I'm not saying this to be pithy, the biggest component is simply that the stage lands on a solid base rather than being dunked, or slammed into to be more accurate, highly corrosive salt water. Reusability isn't so much a function of any huge advancement in inspection so much as the ability to execute a controlled landing of the first stage. Although there are quite a few advancements in metallurgy and materials science, not to mention NDT procedures, that do increase the life span of components. I know this probably does a very poor job of answering your questions but it's the best I can do. [1]http://spacenews.com/spacex-gaining-substantial-cost-savings-from-reused-falcon-9/ http://spacenews.com/spacex-gaining-substantial-cost-savings...

babyrainbow 9y ago
> so much as the ability to execute a controlled landing of the first stage... Pardon me if I am wrong here. But it seems to me that you are suggesting that most of the damage that a rocket sustains, that makes it not fit for reuse, does not happen during the launch and re-entry, but during landing and salt water? But if that is so, why was this the case with space shuttles? > Although the Space Shuttle Main Engines (SSME) were reusable and going to be used on the SLS rocket, NASA doesn't plan to reuse them. The refurbishing and recertification costs make reuse more expensive than manufacturing new engines. https://www.quora.com/Havent-other-space-companies-thought-of-reusable-rockets/answer/Robert-Frost-1 https://www.quora.com/Havent-other-space-companies-thought-o...
- nickik 9y ago
  I think after the landing the reentry is probably the most problematic. If you can prevent them from burning up and you can land them (and one is implied by the other) you are on a good road. I think the Space Shuttle engines would have been capable of more direct relights. They test fired them quite a bit and the were reusable. NASA was just taking a now risk approach and did not really push the technology forward. Boeing has just received a contract for a first stage with wings that should fly 10 times in 10 days and it essentially uses a SSME. So they seem to believe that they don't need to do that much to make it work.
- Inconel 9y ago
  Apologies again for not understanding, but I’m unsure exactly what you’re asking with the question why was this the case with space shuttles. With regards to the SSME, the SSME is an engineering marvel, but it is significantly more complex than the Merlins you’ll find on Falcon, both in initial build as well as refurb. I know a few techs here who used to work on them at Rocketdyne. Raptor will be more analogous to the SSME but there have been significant advancements in metallurgy and materials science since the introduction of the SSME, which should hopefully lead to easier reuse. Also, it should be noted that the SSME were in fact refurbed and reused when they were part of the Shuttle program. As to your quote from Quora, I find it somewhat ambiguous. Again, the SSME was routinely refurbed and reflown as part of the Shuttle Orbiter. I’m no expert on the SLS program, although I do keep up with things space related, but I’ve yet to see any cost breakdowns of refurb vs new build in regards to SSME specifically. That quote makes it unclear to me whether NASA found that reusing the SSME as part of the SLS program is cost prohibitive, or whether making the first stage of the SLS reusable, which happens to use the SSME, is cost prohibitive. It should be noted that the SSME and RS-25 are largely the same engine, and later flights of SLS will switch to a cheaper non-reusable version of the RS-25. In any case, the first stage of the SLS is going to end up in a giant pond of salt water, along with the attached SSME/RS-25s. SLS was never designed for propulsive landing, and can not be made to do so now, so those engines are ending up in the ocean no matter what. Perhaps the poster means that NASA found the refurb costs of the SSME to be prohibitive after they have been dunked in salt water, again, since this is the only possible outcome with SLS. Obviously if the first stage of SLS landed on solid ground, or a ship at sea, the refrub cost of the SSME would be completely different.

babyrainbow 9y ago

> so much as the ability to execute a controlled landing of the first stage... Pardon me if I am wrong here. But it seems to me that you are suggesting that most of the damage that a rocket sustains, that makes it not fit for reuse, does not happen during the launch and re-entry, but during landing and salt water? But if that is so, why was this the case with space shuttles? > Although the Space Shuttle Main Engines (SSME) were reusable and going to be used on the SLS rocket, NASA doesn't plan to reuse them. The refurbishing and recertification costs make reuse more expensive than manufacturing new engines. https://www.quora.com/Havent-other-space-companies-thought-of-reusable-rockets/answer/Robert-Frost-1 https://www.quora.com/Havent-other-space-companies-thought-o...

nickik 9y ago
I think after the landing the reentry is probably the most problematic. If you can prevent them from burning up and you can land them (and one is implied by the other) you are on a good road. I think the Space Shuttle engines would have been capable of more direct relights. They test fired them quite a bit and the were reusable. NASA was just taking a now risk approach and did not really push the technology forward. Boeing has just received a contract for a first stage with wings that should fly 10 times in 10 days and it essentially uses a SSME. So they seem to believe that they don't need to do that much to make it work.
Inconel 9y ago
Apologies again for not understanding, but I’m unsure exactly what you’re asking with the question why was this the case with space shuttles. With regards to the SSME, the SSME is an engineering marvel, but it is significantly more complex than the Merlins you’ll find on Falcon, both in initial build as well as refurb. I know a few techs here who used to work on them at Rocketdyne. Raptor will be more analogous to the SSME but there have been significant advancements in metallurgy and materials science since the introduction of the SSME, which should hopefully lead to easier reuse. Also, it should be noted that the SSME were in fact refurbed and reused when they were part of the Shuttle program. As to your quote from Quora, I find it somewhat ambiguous. Again, the SSME was routinely refurbed and reflown as part of the Shuttle Orbiter. I’m no expert on the SLS program, although I do keep up with things space related, but I’ve yet to see any cost breakdowns of refurb vs new build in regards to SSME specifically. That quote makes it unclear to me whether NASA found that reusing the SSME as part of the SLS program is cost prohibitive, or whether making the first stage of the SLS reusable, which happens to use the SSME, is cost prohibitive. It should be noted that the SSME and RS-25 are largely the same engine, and later flights of SLS will switch to a cheaper non-reusable version of the RS-25. In any case, the first stage of the SLS is going to end up in a giant pond of salt water, along with the attached SSME/RS-25s. SLS was never designed for propulsive landing, and can not be made to do so now, so those engines are ending up in the ocean no matter what. Perhaps the poster means that NASA found the refurb costs of the SSME to be prohibitive after they have been dunked in salt water, again, since this is the only possible outcome with SLS. Obviously if the first stage of SLS landed on solid ground, or a ship at sea, the refrub cost of the SSME would be completely different.