SpaceX (general discussion)

Last I saw there was a booster on deck, but a lot of fire as the image froze! WTF!!!!! This is killing me!

David
 
Musk says booster had a "RUD" on droneship. What is a RUD?

Apparently 1 of the 3 engines was low on thrust. I'm guessing this means it landed too hard and was badly damaged/destroyed.
 
Huh. Liked like it landed upright when the camera froze. :'(
 
sferrin said:
Huh. Liked like it landed upright when the camera froze. :'(
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yes i got same impression, also that Footage of satellite separation look identical like March launch of Boeing satellite....
 
Looks like the cause of the failure wasn't low thrust but simply ran out of gas.

Must Tweet: "Looks like early liquid oxygen depletion caused engine shutdown just above the deck"
https://www.youtube.com/watch?v=p5_hvVbxAAo
 
Hence the fire and black smoke as the image froze -- the engine was pumping kerosene all over the deck when the O2 went dry. Makes sense. Ouch!

Wonder if there's any margin in the braking burn to leave enough for the landing maneuver?. (like this thing is not toasty enough on re-entry).

Next time!

David
 
fredymac said:
Looks like the cause of the failure wasn't low thrust but simply ran out of gas.

Must Tweet: "Looks like early liquid oxygen depletion caused engine shutdown just above the deck"
https://www.youtube.com/watch?v=p5_hvVbxAAo
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IMO that's actually good news.
 
Is it me or does it seem a bit like it mistimed the suicide burn or had a target / vehicle altitude error? At about 8 seconds in it's velocity flattens out as if it's reached its touchdown speed and is waiting for something like leg contact to signal engine cut-off (it'd be neat if we could make out when the leg deploys in that video). Still being some 40 metres in the air however, it continues to descend at about the same rate for 6 seconds before it drops due to fuel exhaustion in an engine.
 
I wouldn't be surprised if they had tweaked their landing software to reduce the possibility of having another crumpled leg. They were just 2-3 seconds from touchdown so a case of over correction and bad luck.

I would guess that altitude over the drone ship is calculated by both on-board and barge mounted sensors to enhance accuracy. No idea if that is true however.
 
Yes, the landing profile vs the previous landing attempts is very weird, guess they are trying out different stuff.

On a related note, reading russian forum about their attempts is enraging and sad at same time. Many of them are acting like pathetic extremely jealous (without admitting so of course) children. Lets hope that people that actually make decisions and engineers are not this... thick. Out of anyone (ULA, China, Airbus etc), Russians have by far the best chance to make a compleing partly reusable system to compete with SpaceX.
 
flanker said:
Yes, the landing profile vs the previous landing attempts is very weird, guess they are trying out different stuff.

On a related note, reading russian forum about their attempts is enraging and sad at same time. Many of them are acting like pathetic extremely jealous (without admitting so of course) children. Lets hope that people that actually make decisions and engineers are not this... thick. Out of anyone (ULA, China, Airbus etc), Russians have by far the best chance to make a compleing partly reusable system to compete with SpaceX.
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What partly reusable systems? There have been only landed stages. Reusing is a different matter
 
Byeman said:
What partly reusable systems? There have been only landed stages. Reusing is a different matter
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The first re-flight is scheduled for later this year.
 
Next Monday at 12:45am is next launch with Dragon re-supply flight and landing back on land.

In the meantime, Dragon crewed capsule is undergoing load tests. I think Boeing and Spacex are still planning on a 2017 first flight (unmanned) for their crew transport capsules.
 

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Thanks for the heads-up on the Monday launch and fly-back to launch-site (well, close to launch site). That kind of eye-candy I will loose sleep over!

And I can't wait for that second-hand booster flight coming up later. Feels a bit like those heady days of the 60's now that Bezos and Musk are show'n e'm how its done (with hard-won knowledge curtesy of the old NASA and its young-aggressive-risk taking-dedicated core of contractor Engineer's).

(Today the only neat thing NASA has come up with is new means of making people ride solids, and throwing perfectly good SSME's into the Atlantic ... wow!).

David
 
https://techcrunch.com/2016/07/17/spacex-successfully-brings-a-rocket-back-to-land-for-the-second-time/
 
People living in the KSC area can now watch rockets landing (and hear the double sonic booms). Once Spacex launches a mission using pre-flown hardware, that will close the loop on the economic concept and make it tough for competitors to not follow suit.

https://www.youtube.com/watch?v=79VAdwjCL4U
 
It's amazing how smooth the landing looks. Really they're getting it. I hope the can do it on Mars.
 
SpaceX does the first full-length test fire of a landed Falcon 9 (F9-024 (JCSAT-14) from May).

https://www.youtube.com/watch?v=SZQY902xQcw
 
Note that JCSAT-14 is the "leader", it went through the worst conditions of any booster so it received maximum forces.
 
Any idea why the exhaust is so dirty? I realize it uses RP-1/kerosene for fuel but I'd have thought it would combust more completely. ???
 
Looks like it's burning pretty fuel rich. Maybe that was done to burn a little cooler. Or maybe it normally burns fuel rich and the soot isn't as visible because the booster is in motion and the soot can't recirculate and hang around.

Or maybe the test stand is cooled with crude oil. The test site "rolls coal" because screw you hippies.
 
The smoke itself is comperable to OG2 SF;

http://i.imgur.com/KO9KEhz.gifv

So i would say it is burning normal.
 
flanker said:
The smoke itself is comperable to OG2 SF;

http://i.imgur.com/KO9KEhz.gifv

So i would say it is burning normal.
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Sure, but is "normal" fuel rich?
 
Well, i honestly doubt they run different ratios depending on whether it is static fire or an actual flight. So i would guess we just see the black smoke because it has low velocity and stays around for a while. In flight it has high velocity and dissipates.
 
flanker said:
Well, i honestly doubt they run different ratios depending on whether it is static fire or an actual flight. So i would guess we just see the black smoke because it has low velocity and stays around for a while. In flight it has high velocity and dissipates.
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Okay. I tried finding video of other RP1/LOX rockets (RD-180 and F-1) to see what they were like on the test stand without much luck. The videos I did find didn't have much visibility of the exhaust.
 
If you look up Merlin testing the smoke from the preburner is very black, and so is F-1s:

https://www.youtube.com/watch?v=liO3blZWv8w

Again, i dont think this is anything unusual. Apparently they did static test fire on the stage again!, supposedly full duration this time too.
 
flanker said:
If you look up Merlin testing the smoke from the preburner is very black, and so is F-1s:

https://www.youtube.com/watch?v=liO3blZWv8w

Again, i dont think this is anything unusual. Apparently they did static test fire on the stage again!, supposedly full duration this time too.
Click to expand...

When I hear 'preburner' I think staged combustion cycle. Maybe you mean gas generator in this context? (both Merlin and F-1 are basic gas generator cycle engines).

David
 
Third SF! 3 full duration static fires of max "damaged" core in 2 days. :eek:
 
With that rate of TF's they only had time to gas it up and replenish the starting fluids. Sounds like minimal maintenance to me. You hear that, Byeman?

David
 
https://www.youtube.com/watch?v=DKqY8sy3nkM

Worth a look if only for 0:55. (Not sure what we're seeing in the shot just before that.)
 
From the Spacex description:
Missions in order of appearance: May JCSAT-14; July CRS-9 launch, stage separation, engine plume interaction, and re-entry burn; December 2015 ORBCOMM landing burn; July CRS-9 landing burn.

It's hard to tell if the re-entry burn is looking at the center engine firing (elliptical annulus shape due to viewing angle).
 
Pausing it at 0:52 made it a little clearer. It's a reentry burn, as you point out, and the flame is squashed. The rocket is at upper left and direction of travel to the lower right.
 
Very cool video.
The elliptical annulus shape is not from viewing angle. Rather a pretty neat exhaust interference between the three engines, and perpendicular to the three engines line.
In the original video at 23m48, when the engines are shutting down it becomes clear.
https://youtu.be/FCCyVCvN2bo?t=23m36s
 

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