Quote from: OxCartMark on 02/12/2018 10:54 pmAnd since this 3 stick launch had what appears to my eyes astoundingly underwhelming performance (the 3 stick launch of a ?1500kg? payload only accelerated the second stage to the same speed that some previous F9(s) have pushed very heavy payloads to) I'm lead to think that they were doing a lot of experimenting with what was going on behind that curtain of flame.Agree! Even given a bunch of experimenting, how did they manage to push so little so slowly?
And since this 3 stick launch had what appears to my eyes astoundingly underwhelming performance (the 3 stick launch of a ?1500kg? payload only accelerated the second stage to the same speed that some previous F9(s) have pushed very heavy payloads to) I'm lead to think that they were doing a lot of experimenting with what was going on behind that curtain of flame.
Quote from: OxCartMark on 02/12/2018 10:54 pmI submit for consideration an alternate theory on why they used more fluid than they needed. Its based on Lou's theory but mine happens on the way up rather than the way down. Perhaps on the way up rather than just throttling down the center core (which is visible) they also switched off a few engines and restarted them.Nice theory.During the reentry burn 3-engine portion, you can see an "Eye of Sauron" (got that from Lars Blackmore's talk) effect, in which the longer axis of the plume cross section is orthogonal to the line of the three lit engines. Lars claims that SpaceX doesn't really know why that happens. I didn't see any equivalent effect on the way up. I wouldn't expect it near sea level with the exhaust overexpanded. But once the plume bloomed out, I thought I'd see the effect again, and didn't. Maybe that's because there was a different pressure pattern.QuoteAnd since this 3 stick launch had what appears to my eyes astoundingly underwhelming performance (the 3 stick launch of a ?1500kg? payload only accelerated the second stage to the same speed that some previous F9(s) have pushed very heavy payloads to) I'm lead to think that they were doing a lot of experimenting with what was going on behind that curtain of flame.Agree! Even given a bunch of experimenting, how did they manage to push so little so slowly?And why? It would have been cooler to have enough battery lifetime and impulse to capture the view of doing a gravity assist off the moon.
I submit for consideration an alternate theory on why they used more fluid than they needed. Its based on Lou's theory but mine happens on the way up rather than the way down. Perhaps on the way up rather than just throttling down the center core (which is visible) they also switched off a few engines and restarted them.
Quote from: atsf90east on 02/12/2018 11:10 pmQuote from: rsnellenberger on 02/12/2018 10:57 pmQuote from: Svetoslav on 02/12/2018 04:20 pmOn the other side, Buzz Aldrin went to the pad and watched the liftoff of Falcon Heavy. Jeez... what a way to go! RIP, Buzz... He had a hot time on the way out Seriously though, I'll bet he was either at the Saturn V Center viewing area, or on the roof of the VAB I didn’t see him at the Saturn V center and didn’t hear talk of him being there
Quote from: rsnellenberger on 02/12/2018 10:57 pmQuote from: Svetoslav on 02/12/2018 04:20 pmOn the other side, Buzz Aldrin went to the pad and watched the liftoff of Falcon Heavy. Jeez... what a way to go! RIP, Buzz... He had a hot time on the way out Seriously though, I'll bet he was either at the Saturn V Center viewing area, or on the roof of the VAB
Quote from: Svetoslav on 02/12/2018 04:20 pmOn the other side, Buzz Aldrin went to the pad and watched the liftoff of Falcon Heavy. Jeez... what a way to go! RIP, Buzz...
On the other side, Buzz Aldrin went to the pad and watched the liftoff of Falcon Heavy.
A testament to the power of this first ever launch of the Falcon Heavy, Lt Col Stuker noted, “It was the first time we heard the rumble of the rocket over the sound of the rotor blades.”
Quote from: Alastor on 02/12/2018 05:06 pmhttps://twitter.com/elonmusk/status/963107229523038211Quote from: Elon MuskElon MuskCompte certifié @elonmusk16 minil y a 16 minutesEn réponse ŕ @kerrbones @nextspaceflightNot enough ignition fluid to light the outer two engines after several three engine relights. Fix is pretty obvious.The centre core landing failure was caused by the fact that the need for ignition fluids (TEA/TEB) increases after several engine relights. They are adding more storage to fix the issue.More critical about this.One should always ask, if the fix was so simple, why wasn' t the issue determined before flight (i.e. simulation)?People give SX too many "mulligans", too readily, at any time, and for any reason.Yes it was good the demo launch succeeded.
https://twitter.com/elonmusk/status/963107229523038211Quote from: Elon MuskElon MuskCompte certifié @elonmusk16 minil y a 16 minutesEn réponse ŕ @kerrbones @nextspaceflightNot enough ignition fluid to light the outer two engines after several three engine relights. Fix is pretty obvious.The centre core landing failure was caused by the fact that the need for ignition fluids (TEA/TEB) increases after several engine relights. They are adding more storage to fix the issue.
Elon MuskCompte certifié @elonmusk16 minil y a 16 minutesEn réponse ŕ @kerrbones @nextspaceflightNot enough ignition fluid to light the outer two engines after several three engine relights. Fix is pretty obvious.
QuoteThe performance numbers in this database are not accurate. In process of being fixed. Even if they were, a fully expendable Falcon Heavy, which far exceeds the performance of a Delta IV Heavy, is $150M, compared to over $400M for Delta IV Heavy.https://twitter.com/elonmusk/status/963076231921938432So we now have an actual price for an expendable Falcon Heavy.
The performance numbers in this database are not accurate. In process of being fixed. Even if they were, a fully expendable Falcon Heavy, which far exceeds the performance of a Delta IV Heavy, is $150M, compared to over $400M for Delta IV Heavy.
Quote from: tvg98 on 02/12/2018 03:27 pmQuoteThe performance numbers in this database are not accurate. In process of being fixed. Even if they were, a fully expendable Falcon Heavy, which far exceeds the performance of a Delta IV Heavy, is $150M, compared to over $400M for Delta IV Heavy.https://twitter.com/elonmusk/status/963076231921938432So we now have an actual price for an expendable Falcon Heavy. So that is $90M for 8 t to GTO or $11,250/kg or $150M for 26.7 t to GTO or $5,618/kg. That means if you are sending large payloads to the Moon or Mars, its much cheaper to do it expendable!
Nope. Center core expendable and recovering boosters on ASDS only incurs 10% penalty as per a later tweet... for $95million I speculate this is for reused boosters and is lower to suit the reused rocket prices that were just mentioned in an article on this site: https://www.nasaspaceflight.com/2018/02/falcon-heavy-success-paves-space-beyond-earth/$62M for full 3 core reuse.
Quote from: GWH on 02/13/2018 05:09 amNope. Center core expendable and recovering boosters on ASDS only incurs 10% penalty as per a later tweet... for $95million I speculate this is for reused boosters and is lower to suit the reused rocket prices that were just mentioned in an article on this site: https://www.nasaspaceflight.com/2018/02/falcon-heavy-success-paves-space-beyond-earth/$62M for full 3 core reuse. That means a centre core costs only $5M to make. $95M for 0.9*26.7 = 24.03 t is $3,953/kg, which is the cheapest option.
Quote from: Kabloona on 02/12/2018 10:17 pmQuoteIn some ways, from an engineering perspective, this FH launch was a failure: so many things that could have gone wrong, didn't - and it would certainly be a shame if the only "lesson learned" was that they miscalculated the amount of starter fluid needed. Is the rocket over-engineered? Yes, it's a shame so many things worked properly that the engineers won't know what to fix. But judging from Elon's comment that FH was much harder than they expected, I'd guess they learned quite a lot in the design process about coupled loads, booster separation dynamics, modal analysis, etc, etc. And apparently they learned most, or all, of those lessons well.I'd guess that there's still plenty to fix; just nothing so broken that it resulted in a loss of mission. More fine tuning; less coarse.
QuoteIn some ways, from an engineering perspective, this FH launch was a failure: so many things that could have gone wrong, didn't - and it would certainly be a shame if the only "lesson learned" was that they miscalculated the amount of starter fluid needed. Is the rocket over-engineered? Yes, it's a shame so many things worked properly that the engineers won't know what to fix. But judging from Elon's comment that FH was much harder than they expected, I'd guess they learned quite a lot in the design process about coupled loads, booster separation dynamics, modal analysis, etc, etc. And apparently they learned most, or all, of those lessons well.
In some ways, from an engineering perspective, this FH launch was a failure: so many things that could have gone wrong, didn't - and it would certainly be a shame if the only "lesson learned" was that they miscalculated the amount of starter fluid needed. Is the rocket over-engineered?
Quote from: GWH on 02/13/2018 05:09 amNope. Center core expendable and recovering boosters on ASDS only incurs 10% penalty as per a later tweet... for $95million I speculate this is for reused boosters and is lower to suit the reused rocket prices that were just mentioned in an article on this site: https://www.nasaspaceflight.com/2018/02/falcon-heavy-success-paves-space-beyond-earth/$62M for full 3 core reuse. That means a centre core costs only $5M to make. That would imply three expendable cores should only cost $15M, increasing the price to $110M, not $150 M. Anyway, $95M for 0.9*26.7 = 24.03 t is $3,953/kg, which is the cheapest option. If an expended core costs (150-90)/3 = $20M, that gives a price of $90+$20 = $110M for 24.03 t or $4,578/kg, which is still cheaper than fully expendable.
Its impressive that SpaceX managed to get every first of F9 and FH right the first time.F9 v1.0F9 v1.1 Block IF9 v1.1 Block IIF9 v1.1 Block IIIF9 v1.1 Block IVFH Block III/IVNo kabooms with each launch. Perfect payload delivery.Two losses of payloads, but not on the inaugural launch.Given how many substantial performance improvements and major redesigns for stages, tanks, helium storage, engine uprates, ...It is A M A Z I N G the resulting stats.Hopefully Block V F9 and FH will maintain the pattern.
I understand that the center core did not have the titanium grid fins. Why is that?
Quote from: marsbase on 02/13/2018 10:15 amI understand that the center core did not have the titanium grid fins. Why is that? one of the reasons why titanium fins were needed for side boosters is for control authority as they have rounded nosecones instead of a cylinder which affects flow separation and thus controllability. The titanium fins are larger than the old aluminum fins so they provide more authority.
I've also wondered why the side booster nose cones are not jettisoned like the fairing if that would add control.