Could the following images be the first one of Block 5?IIRC there was a comment that B5 would be immediately recognizable. To me, these cores no longer look completely round. It that what was meant by that comment?
Quote from: Stan-1967 on 02/20/2018 02:33 pmAs to an octagon not being ideal for a pressurized container, this is obviously true, but I don't see that it would be a show stopper, & the core is not pressurized that high ( 40psi? A COPV it is not). You are forgetting head pressure and acceleration. An octagon is a non starterNot going to work with composite interstages.
As to an octagon not being ideal for a pressurized container, this is obviously true, but I don't see that it would be a show stopper, & the core is not pressurized that high ( 40psi? A COPV it is not).
Having said that, I have seen very little in this block 5 speculation thread that explains how F9 will get to the performance specs that were being tossed out by SpaceX. Uprated engine thrust, at the same ISP, eats into gravity losses & therefore increases performance, but total prop & increased vehicle GLOW seems to need to be increased. Weight savings on the legs doesn't leverage much increase in payload to GTO. Where is the performance coming from?
You are forgetting head pressure and acceleration. An octagon is a non starterNot going to work with composite interstages.
Quote from: Jim on 02/20/2018 02:57 pmYou are forgetting head pressure and acceleration. An octagon is a non starterNot going to work with composite interstages.My deal killer for an octagon vehicle is not the engineering problems, I bet they could be solved, but I see zero chance you try something like this on the vehicle you are going to use for commercial crew. ASAP would laugh SpaceX out of contention.Again, my 6 points were just speculating on how an octagon has some theoretical advantages consistent with the statements from SpaceX.
SpaceX has stated that Block 5 will be "the final version" of F9, and clearly SpaceX wants to move on to the BFR.There were comments (from Spacex) about a new leg design, changes for rapid reusability, an update to the Merlin engines to address known issues, and I believe a thrust increase.What we don't know is what they're planning to include with F9B5Will F9B5 have features that will help with BFR development (e.g. an option for cradle landing?)Will there be provisions for barge fly-back? (as per an isolated comment from Musk a while back?)Also in-scope: FHB5Stay tuned!
Can you truly have the kind of rapid re-usability that Elon talks about without a cradle style landing? Just lifting the S1 and resetting legs (regardless of design) would seem like a non-trivial, time consuming procedure.
Quote from: gregpet on 02/24/2018 06:54 pmCan you truly have the kind of rapid re-usability that Elon talks about without a cradle style landing? Just lifting the S1 and resetting legs (regardless of design) would seem like a non-trivial, time consuming procedure.Why?Container cranes - some of the larger ones - routinely carry payloads of similar masses around at high speed.The 'octograbber' type idea in principle could also rapidly and quickly position a stage.Even if you look at actual current manual procedures of getting the S1 off the barge, they're remarkably faster than they were.In principle there seems little stopping the F9 landing very near the launchpad, being rapidly checked out, and relaunched well within a week - at least - the 'get the empty stage to a known consistent position' is not a limiter.No, you're not going to do passenger launches of it ten times a day. (probably)
NASA is requiring SpaceX to fly a “frozen” configuration of the Block 5 – meaning every vehicle is built the same way – successfully for at least 7 flights.
And is it truly that SpaceX must build and fly 7 separate cores? Or can some of those 7 be re-flights?
The quick turn-around may follow a few flights/reflights of Block 5.Should take the time to check that your design is performing as planned.
Quote from: AncientU on 03/10/2018 04:15 pmThe quick turn-around may follow a few flights/reflights of Block 5.Should take the time to check that your design is performing as planned.Yeah, I owuldn't be surprised if they did a teardown of the first one or two cores post-landing, similar to what is done with the FT cores for refurb.Check every little spot for issues.
Quote from: IanThePineapple on 03/10/2018 04:18 pmQuote from: AncientU on 03/10/2018 04:15 pmThe quick turn-around may follow a few flights/reflights of Block 5.Should take the time to check that your design is performing as planned.Yeah, I owuldn't be surprised if they did a teardown of the first one or two cores post-landing, similar to what is done with the FT cores for refurb.Check every little spot for issues.They have done that very thoroughly on the landed boosters already. They have identified spots that don't hold up very well and/or are not easily refurbished. They have upgraded those spots. They now need to check how the upgrades hold up to expectations. That does not need redoing the full inspection of the vehicle. That will come after 3 or 4 flights probably.
Quote from: Testraindrop on 02/18/2018 10:21 pmMaybe they will put some clear coat on the CF, like car manufacturers do...But why, when the whole point of using that material is to reduce weight?
Maybe they will put some clear coat on the CF, like car manufacturers do...