Author Topic: LIVE: ASDS OCISLY - with Thaicom-8 S1 - Return Coverage - May-June, 2016  (Read 339161 times)

Offline manoweb

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Actually SpaceX has stated only CSR8 will be able to refly at this point, the other 2 returns have to much damage but will be good to study

Well, not exactly...

https://twitter.com/elonmusk/status/734274360588926976

Offline Rocket Science

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Alicia is back! :)
"The laws of physics are unforgiving"
~Rob, Physics instructor, aviator, vintage auto racer

Online wannamoonbase

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Actually SpaceX has stated only CSR8 will be able to refly at this point, the other 2 returns have to much damage but will be good to study

Well, not exactly...

https://twitter.com/elonmusk/status/734274360588926976


These claims are hard(er) to believe until we actually see one of these charred sticks fly again.
Excited to be finally into the first Falcon Heavy flow, we are getting so close!

Offline xtc

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Out at Fishlips finally!

They're getting the crane in position now it seems.

Online tleski

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It's not hydraulic fluid. If it was leaking they would've lost pressure and the fins wouldn't have been working on landing.

It is not a closed system.

We know, it's RP-1. If it was leaking they'd run out and it would be CRS-5 all over again :)

Please quote your source. As far as I know there was an extensive discussion about this in some threads here but never a solid source confirming that the hydraulic fluid used is RP-1. We know that it is an open system but not what the working fluid is.

Offline bstrong

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Actually SpaceX has stated only CSR8 will be able to refly at this point, the other 2 returns have to much damage but will be good to study

Well, not exactly...

https://twitter.com/elonmusk/status/734274360588926976


These claims are hard(er) to believe until we actually see one of these charred sticks fly again.

Maybe, but that doesn't mean you can claim they said the opposite of what they actually said.

Offline cscott

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Also: "open system" means precisely that the fluid is exhausted out some port after use.  Although there was speculation that they'd try to recapture the exhaust into the main propellant tank if the working fluid was RP-1, I think before Occam's Razor would point to these pictures as proof that the exhaust is dumped overboard, as most experienced hands had thought would be the case.

That is: this is what the open loop hydraulic grid fin system looks like after nominal operation.  No "leak" other than the designed-in exhaust port.

Offline the_other_Doug

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Did manage to download the pic. Does the top of the stage look a bit buckled to anyone else?

https://www.instagram.com/p/BGKRcY3F8XC/

Edit: First line changed and picture attached.

Okay, I take back my earlier post about all of the landing pads being on or inside the outer white circle.  Per this picture, one landing pad is most definitely outside of the white circle, and, yeah, y'all are right -- right up to the yellow railing.

That railing isn't really meant to be load-bearing, I don't think.  It's to stop people from wandering around, not looking at their feet, and walking off the deck.  They'll give you some support, but I don't think they would stop a stage from just walking off the deck.  But, yeah -- that sucker sure did walk right on across, didn't it?

The landing bingo winner is gonna be... unexpected.
-Doug  (With my shield, not yet upon it)

Online vanoord

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In fact, I don't know how safe it is to say that the residue is hydraulic fluid, it was speculated before it can just be the TPS on the fins peppering the interstage... although its distribution does make it appealing to give credence to this possibility.

I think we've had the evidence in the descent video to work out why there is much worse staining above one of the grid fins.

Basically, I reckon it's deposits of scorched paint and other ablative materials that are deposited during re-entry.

Immediately after the re-entry burn, the camera housing is clouded by material which looks about right to be scorched paint etc. and this is apparently blown away as the stage descends.

But why is it concentrated above one grid fin?

Looking at the video again, it shows that the angle of attack other than during the burn is slightly above the trajectory - it's conjectured that this is to trade a bit of speed for distance and therefore spread the re-entry heating over a slightly longer period.

This angle of attack changes the airflow through the fins - on the Earth-facing side, the airflow will bend slightly towards the stage and allow deposition of material onto the vehicle - that may also cause concentration of hot gasses which will burn the paint away.


Offline manoweb

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To me the yellow part looks very solid, made of steel, and capable of stopping many tons.

Offline cookiejar5

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I used my binocular lens to get a close up of the cap.

Offline ccicchitelli

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That is: this is what the open loop hydraulic grid fin system looks like after nominal operation.  No "leak" other than the designed-in exhaust port.

That would make a lot of sense.

Offline Helodriver

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It seems that one and probably two legs have compressed crush cores allowing a good pendulum teetering action to develop and increase in amplitude by further compressing the cores with the continuous rocking on deck. That bigger teeter caused incremental sliding toward the most compressed leg with each jarring stop, arrested only by the yellow I beam railing around the deck edge.

Whoever first came up with the idea for that railing around the ASDS deserves a serious attaboy from Elon. That saved the rocket from walking overboard.

Online MarekCyzio

Also: "open system" means precisely that the fluid is exhausted out some port after use.  Although there was speculation that they'd try to recapture the exhaust into the main propellant tank if the working fluid was RP-1, I think before Occam's Razor would point to these pictures as proof that the exhaust is dumped overboard, as most experienced hands had thought would be the case.

That is: this is what the open loop hydraulic grid fin system looks like after nominal operation.  No "leak" other than the designed-in exhaust port.

I do not remember seeing anything like that during previous flights, so I vote for a small leak.

Offline cookiejar5

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Am I the only Nasaspaceflight member on this cruise?

Offline sevenperforce

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SpaceX just helpfully posted this graphic of the Apollo landing legs:


Offline cookiejar5

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Man lift with two workers are almost to the top of the stage

Offline xtc

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Manlift now inspecting top of stage and crane.

Offline cookiejar5

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Online AncientU

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That is one tall manlift!
"If we shared everything [we are working on] people would think we are insane!"
-- SpaceX friend of mlindner

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