If you think about it, the control algorithms must be awfully impressive to deal with the rapidly changing flight dynamics! They deal with essentially no atmosphere, supersonic thin through thicker atmosphere, transoceanic, and subsonic with three different control methods of varying power all of which substantially change over time. I mean, the rocket flies beautifully with the grid fins vaporizing during flight! Imagine how the system must deal with some fins producing more drag (but not predictable before hand drag) from worse and worse flow properties (due to some parts no longer being there). I mean, adaptive controls have been in flight systems for ages but its still amazing just how controlled these flights are with so much changing!
It seems that telemetry (not just video) from the 1st stage was lost towards the end of the entry burn (?) and those monitoring had to use external sources to keep track of it (??).Had that happened before AFTS on that stage had been safe, would it blew the stage up?
42967/2017-063A: 309 x 40519 km x 27.89 deg42968/2017-063B: 313 x 40517 km x 27.88 deg
Quote from: mvpel on 10/11/2017 11:10 pmI was thinking the same thing about the plasma, but then got worried when it didn't pick up again. Held my breath until I started hearing the descent callouts.I was really amazed to see that it was showing 6,000 km/h when the entry burn ended, is that a record?I am sure some of the spacex stats geeks around here will have that info soon! But yeah 6000 seems pretty quick. Also since they arent doing 3 engine landing burn attempts anymore (for now) They could be hunting for ways to trim down on the entry burn requirements by seeing how little they need to slow the stage down "This one wasnt burned up that badly? Hmmm, cut the burn off another 2 seconds early and see what happens! Its just a block 3!"
I was thinking the same thing about the plasma, but then got worried when it didn't pick up again. Held my breath until I started hearing the descent callouts.I was really amazed to see that it was showing 6,000 km/h when the entry burn ended, is that a record?
The titanium fins are slightly longer and cover the bottom-of-fin attach point protrusion on the body completely, Have a scalloped front face, And for the moment are unpainted and dark grayish instead of white.As far as the glow, I'm halfway surprised I never saw big chunks blowing by the camera. Whatever ablative coating is used on them earned it's pay today.
I'm sure Chris G's article said this was a three engine landing burn.
Quote from: meekGee on 10/12/2017 02:41 amQuote from: edkyle99 on 10/12/2017 12:21 amLooks like another stage that won't fly again. There have been 12 first stage recovery flights this year, but only three of them were GTO missions and all three were first stage reflights (using "used" first stages). My guess is that these are R&D flights on the reuse side that won't see their stages used again (the SES-10 and Bulgariasat stages have been retired or mothballed). They would have been expendable flights otherwise. The other three GTO missions this year were expendable missions.A bit of a weenie roast after this landing! - Ed Kyle People have been saying that on every core that comes down a little stressed.Remember Thaicom 8? Not sure what the point is, but it's a popular refrain.Regardless of if it can be reflown, they won't do any 3rd flights for anything as long as they have single flight cores hanging around everywhere or it makes more sense to fly/refly block 5 cores.
Quote from: edkyle99 on 10/12/2017 12:21 amLooks like another stage that won't fly again. There have been 12 first stage recovery flights this year, but only three of them were GTO missions and all three were first stage reflights (using "used" first stages). My guess is that these are R&D flights on the reuse side that won't see their stages used again (the SES-10 and Bulgariasat stages have been retired or mothballed). They would have been expendable flights otherwise. The other three GTO missions this year were expendable missions.A bit of a weenie roast after this landing! - Ed Kyle People have been saying that on every core that comes down a little stressed.Remember Thaicom 8? Not sure what the point is, but it's a popular refrain.
Looks like another stage that won't fly again. There have been 12 first stage recovery flights this year, but only three of them were GTO missions and all three were first stage reflights (using "used" first stages). My guess is that these are R&D flights on the reuse side that won't see their stages used again (the SES-10 and Bulgariasat stages have been retired or mothballed). They would have been expendable flights otherwise. The other three GTO missions this year were expendable missions.A bit of a weenie roast after this landing! - Ed Kyle
Quote from: Kaputnik on 10/12/2017 08:24 amI'm sure Chris G's article said this was a three engine landing burn.I don't think we saw the landing burn, but my understanding has been that the stage lands on a single engine, even if three have been lit during the burn - they are ramped up and down 1 engine / 3 engines / 1 engine, hence the description as a 1-3-1 burn. To me, that makes sense as a change in throttle level on a single engine gives a less aggressive thrust change, particularly at the point of touch-down - and from memory, the attempts to touch down with three engines lit haven't been particularly easy viewing. That said, a quick skip through the recent landings is pretty inconclusive, as the moment of landing is either not seen either due to video drop-out on the ASDS - or from too far away for RTLS.
Ready for a scary thought....BulgariaSat-1 was going ~600km/h faster at the end of the entry burn then this one!!
... so as long as they reduce vertical velocity during the reentry burn, they'll manage to bleed off the horizontal velocity without any problem.
Hello,I'm here for the 1st time at Cape Canaveral.Do you know when the drone ship is planned to go back at the port with the first stage ?
Quote from: jimbowman on 10/11/2017 11:06 pmWas it just because it was dark out the heat on the grin fins was more visible? Was the Iridium launch using titanium?Iridium was also aluminumWas stated during the launch webcast due to lower energy trajectory.This SES-11 was obviously not a lower energy trajectory, so we can assume they are using (or rather burning) up their stock of aluminum ones.
Was it just because it was dark out the heat on the grin fins was more visible? Was the Iridium launch using titanium?
Quote from: meekGee on 10/12/2017 02:41 amQuote from: edkyle99 on 10/12/2017 12:21 amLooks like another stage that won't fly again. There have been 12 first stage recovery flights this year, but only three of them were GTO missions and all three were first stage reflights (using "used" first stages). My guess is that these are R&D flights on the reuse side that won't see their stages used again (the SES-10 and Bulgariasat stages have been retired or mothballed). They would have been expendable flights otherwise. The other three GTO missions this year were expendable missions.A bit of a weenie roast after this landing! - Ed Kyle People have been saying that on every core that comes down a little stressed.Remember Thaicom 8? Not sure what the point is, but it's a popular refrain.Thaicom 8 weighed only 3 tonnes. The other reused boosters flew LEO missions first, then launched heavier-than-Thiacom 8 satellites to GTO.Remember NROL 76? LEO mission, stage reportedly mothballed after LZ 1 landing. What about JCSAT 16's stage, scrapped after a GTO launch? I count at least five stages retired, mothballed, or scrapped to date out of 15 stages recovered to date, six if B1031.2 ends up retired. - Ed Kyle
Any idea what the velocities were on the early experimental flights they did with F9 where the stage broke up as soon as it hit the atmosphere (early recovery days)?
(snip)But this will clearly change - SpaceX has only re-flown 3 times this year. The direction it's heading, especially with more advanced revisions of F9, is clear...
