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#740
by
cro-magnon gramps
on 31 Mar, 2017 00:59
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I'm reminded of the discussion regarding whether there would be enough fuel for the landing... that it was coming in HOT as one person said...
has anyone an idea what Spx did to manage this landing...
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#741
by
Jcc
on 31 Mar, 2017 01:02
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Thought they had shelved 2nd stage reuse for F9. Looks like is back on the todo list.
We only have what has been posted by CG, and that doesn't indicate reusable 2nd stage for F9 but just that it is next on the list of capabilities to develop to achieve their ultimate goal.
Some more context in Jeff Foust's tweet:
Musk adds it might “fun to try a Hail Mary” and recover an upper stage.
A possible mission with upper stage recovery testing could be the FH demo.
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#742
by
Lar
on 31 Mar, 2017 01:25
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EDIT: The stage must be re-entering at an angle to affect the grid fins so differently.
Yes, we've seen that asymmetry on photos of recovered stages, where the white paint on the interstage above one of the grid fins has been blasted off by the TPS coming off the grid fin, but the white paint remains intact on the opposite side of the interstage.
Maybe they need to BBQ roll the stage for the high heat part of the descent?
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#743
by
old_sellsword
on 31 Mar, 2017 01:28
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EDIT: The stage must be re-entering at an angle to affect the grid fins so differently.
Yes, we've seen that asymmetry on photos of recovered stages, where the white paint on the interstage above one of the grid fins has been blasted off by the TPS coming off the grid fin, but the white paint remains intact on the opposite side of the interstage.
Maybe they need to BBQ roll the stage for the high heat part of the descent?
Thaicom 8 (another GTO mission) was rock-steady throughout the descent. They seem to be very tightly roll-controlled during the whole launch and landing.
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#744
by
macpacheco
on 31 Mar, 2017 01:34
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Can anyone offer a suggestion for the least laggy streaming site? I've tried SpaceX, Youtube, Ustream with varying results.
I think youtube has a problem today.
My ISP... I actually work for them. I'm their last line of technical support. I watched the hosted webcast about 60 minutes after the launch started, and it was still very crappy. We have 2x10Gbps upstream links and all of them have several Gbps of spare bandwidth and we also host a google cache. I have 100Mbps symmetric bandwidth. Still it was so crappy to watch I almost resorted to downloading the video file and watching it offline (only possible after the webcast is finished).
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#745
by
Lar
on 31 Mar, 2017 01:36
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EDIT: The stage must be re-entering at an angle to affect the grid fins so differently.
Yes, we've seen that asymmetry on photos of recovered stages, where the white paint on the interstage above one of the grid fins has been blasted off by the TPS coming off the grid fin, but the white paint remains intact on the opposite side of the interstage.
Maybe they need to BBQ roll the stage for the high heat part of the descent?
Thaicom 8 (another GTO mission) was rock-steady throughout the descent. They seem to be very tightly roll-controlled during the whole launch and landing.
I'm saying maybe they might want to change that... induce a deliberate roll. But that makes the control algorithms more complex I expect.
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#746
by
Herb Schaltegger
on 31 Mar, 2017 01:44
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I'm saying maybe they might want to change that... induce a deliberate roll. But that makes the control algorithms more complex I expect.
I would think you would want to avoid inducing roll for fear of centrifuging fluids in the grid fin hydraulics (leading to loss of control) or inducing slosh as well as centrifuging in the propellant tanks. That could cause issues with restart for the landing burn.
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#747
by
Lar
on 31 Mar, 2017 01:47
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I'm saying maybe they might want to change that... induce a deliberate roll. But that makes the control algorithms more complex I expect.
I would think you would want to avoid inducing roll for fear of centrifuging fluids in the grid fin hydraulics (leading to loss of control) or inducing slosh as well as centrifuging in the propellant tanks. That could cause issues with restart for the landing burn.
BBQ roll doesn't have to be FAST, so not a LOT of slosh probably? .... but yeah, since they did lose an early mission to slosh, titanium and no roll is probably cheaper.
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#748
by
Okie_Steve
on 31 Mar, 2017 01:55
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Maybe not something to try now, but sounds perfect to test with EOL booster if they think control is up to it. Spreading heat means possible hotter landings and larger envelope.
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#749
by
Okie_Steve
on 31 Mar, 2017 02:03
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If Elon decides to go for the Hail Mary 2nd stage recovery from presser, what sort of mission would likely provide best chance. Circular LEO or ellipse GTO?
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#750
by
jketch
on 31 Mar, 2017 02:07
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Certainly circular LEO. Ellipse GTO missions will be going about 2km/s faster at perigee, which would make for a much tougher reentry.
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#751
by
Wolfram66
on 31 Mar, 2017 02:24
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Did everyone notice the lightning flashes from thunderstorms on the western coast of Africa shortly after SECO-1? Can be seen off the lower left of engine bell
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#752
by
Jdeshetler
on 31 Mar, 2017 02:28
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Probably no titanium 3D printer big enough. Anyway, large metal 3D printing is expensive, has inferior surface finish, and produces lower strength than a forging. Forging is better especially if you'll be making several copies (SpaceX will make at least 100 of them).
This Military History clip showed the SR-71's titanium frames being manufactured in 1960. It looks like it was a simple forged then bended.
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#753
by
manoweb
on 31 Mar, 2017 02:32
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debut of Roomba
Is the above true? I have not seen evidence it was used
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#754
by
manoweb
on 31 Mar, 2017 02:33
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Looked like the grid fin on the right was getting a good cooking before the feed cut.
To me it almost looked like they cut the feed on purpose when they saw it burn... is it possible? But then it still made it to the barge!!!
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#755
by
Jcc
on 31 Mar, 2017 02:53
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Wait.. Falcon 9 version 2.5? Mind blown!
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#756
by
ChrisGebhardt
on 31 Mar, 2017 02:53
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debut of Roomba
Is the above true? I have not seen evidence it was used
Roomba debut in "a few months" according to Elon at the presser.
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#757
by
ClayJar
on 31 Mar, 2017 02:56
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debut of Roomba
Is the above true? I have not seen evidence it was used
I listened to the presser all the way through now, and it sounded like Elon indicated that it's really only needed in heavier seas. Apparently, when the water's in a kinder, gentler mood, the stages aren't likely to be jogging around the ASDS, so you don't have a pressing need to get them remotely locked down.
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#758
by
Clueless Idiot
on 31 Mar, 2017 03:11
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I don't have the time to read through everything, so was this a one or three engine landing burn, how many three engine landings have they done so far isn't it just one?
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#759
by
Space Ghost 1962
on 31 Mar, 2017 03:14
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Key take-away: Musk says he is pivoting the launch business - to be competitive, you have to do rapid reuse.
Otherwise, you're at a 100x cost disadvantage. Eventually 1000x.
Now watch all the other providers scramble.