I've more gotten the sense that S2 reuse with Falcon 9s is certainly *possible*, but would leave F9-R with too little payload to GTO to be commercially worthwhile<snip>Except... the assumption buried in there is that F9 and FH primarily fly to GTO.<snip>F9's GTO performance is sub-par for the rocket's size due to the relative inefficiency of the gas-generator-powered and keorolox-fueled S2. On the other hand, its LEO performance is quite the opposite, and much better able to absorb any S2 reuse penalty while leaving a commercially relevant amount of performance for payloads.Say, for example, a SpaceX constellation of small LEO comsats, where a penny saved on launch costs is a penny earned, since SpaceX will have only themselves to foot the bill.
The cost benefit of introducing a 2nd stage that diverges too strongly from these design, manufacturing efficiencies in order to facilitate return/reuse of a new 2nd stage are currently not present. IMO. Which is why I suspect they moved away from that and have now modified the current F9 design to accommodate returning the core stage even when delivering higher mass to more difficult orbits, while not disrupting their basic design and manufacturing layout efficiencies to any great extent.
However, I agree, that in the future, if they can solve the technical and cost implications of 2nd stage expendable vs. re-use, they will attempt to do so. But I'm not seeing it anytime soon. There's bigger fish to fry right now. So to speak. But this is SpaceX, so who knows.....
Yes the concept of a reusable (or custom?) S2 for the Alphabet/Google satellite business is interesting.
I don't believe SpaceX will do a fully reusable Merlin based LV.The ISP is too low.
Elon Musk said a while back something like we figured out how to significantly reduce our manufacturing costs and scale, so reuse isn't a big hurry.
Full reuse will wait until Raptor/LNG rockets show up.
Quote from: GregA on 09/08/2015 12:04 amYes the concept of a reusable (or custom?) S2 for the Alphabet/Google satellite business is interesting.Custom, eh? :-)Well, I wonder how much SYLDAs cost, and what SpaceX thinks of all the dispensers abandoned in orbit.4000 sats at 40 sats per FH-R is still a hundred flights -- more if FHs can lift fewer or if F9-Rs are tapped to deliver some. That's a *lot* of flights -- even a low rate of savings can add up to a substantial R&D budget.
Quote from: rcoppola on 09/07/2015 06:44 pmHowever, I agree, that in the future, if they can solve the technical and cost implications of 2nd stage expendable vs. re-use, they will attempt to do so. But I'm not seeing it anytime soon. There's bigger fish to fry right now. So to speak. But this is SpaceX, so who knows..... Bigger fish indeed, for now. For years, even.Elon, however, seems to be playing the long game -- and as the seasons and years have come and gone, I've noted that "not soon" has a distressingly inexorable way of somehow becoming "tomorrow". ;-)
Quote from: guckyfan on 09/07/2015 03:31 pmGreat article with lots of interesting data.I did stumble over this sentence:QuoteSpaceX opted against recovery attempts of this stage in its current configuration.It does sound like there might be a new configuration coming that would be reusable. Perhaps I am overinterpreting?They have said there's a potential path with a different type of second stage.
Great article with lots of interesting data.I did stumble over this sentence:QuoteSpaceX opted against recovery attempts of this stage in its current configuration.It does sound like there might be a new configuration coming that would be reusable. Perhaps I am overinterpreting?
SpaceX opted against recovery attempts of this stage in its current configuration.
Great article Chris! It includes exactly the right level of information for readers like me. Thanks!Quote from: GreenShrike on 09/07/2015 05:20 pmfull reuse will have to wait the opening of a new market that a fully reusable F9 and/or FH can commercially target with success. GTO flights are not that market.Well said. Also, engineering for full reuse could distract from the tasks at hand, i.e. return to flight and the simultaneous first flight of F9 Full Thrust. That probably involves enough work to keep everyone busy for awhile....(Personally I hope they find a Mars architecture built on full reuse of F9-like vehicles filling a propellant depot in LEO. That propellant would then be transferred to the MCT for TMI. But that definitely seems like "future work.")
full reuse will have to wait the opening of a new market that a fully reusable F9 and/or FH can commercially target with success. GTO flights are not that market.
http://www.nasaspaceflight.com/2015/09/spacex-conducts-falcon-9-improvements-busy-schedule/Edit to the above article as there's now a first stage raised on to the *NEW* test stand at McGregor as of today, per L2.
Quote from: Chris Bergin on 09/08/2015 08:39 pmhttp://www.nasaspaceflight.com/2015/09/spacex-conducts-falcon-9-improvements-busy-schedule/Edit to the above article as there's now a first stage raised on to the *NEW* test stand at McGregor as of today, per L2.Tut-tut. You said "EDIT: On Tuesday morning, engineers raised a first stage onto the new test stand that will be used for both Falcon 9 v1.2 and Falcon Heavy testing."There is no F9 v1.2 only v1.1 full thrust or F9-FT?. We must all stop using the ver 1.2!
It is currently the only test stand that can be utilized for the upgraded Falcon 9’s slightly increased length
Thanks for this article .Quote It is currently the only test stand that can be utilized for the upgraded Falcon 9’s slightly increased length Has the first stage length also increased ?