SpaceX Dragon CRS-5 ISS resupply


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SALSN

From the webcast site:

Rocket made it to drone spaceport ship, but landed hard. Close, but no cigar this time. Bodes well for the future though.

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DocM

@elonmusk

Rocket made it to drone spaceport ship, but landed hard. Close, but no cigar this time. Bodes well for the future tho.

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DocM

@elonmusk

Didn't get good landing/impact video. Pitch dark and foggy. Will piece it together from telemetry and ... actual pieces.

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elonmusk

Ship itself is fine. Some of the support equipment on the deck will need to be replaced...

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FloatingFatMan

So, it didn't survive the landing, but DID actually make it on target? That's good!

 

Edit: Correction. it DID survive the landing! Even better!


@elonmusk
Didn't get good landing/impact video. Pitch dark and foggy. Will piece it together from telemetry and ... actual pieces.

 

You'd think they'd have multiple redundant camera's going, including night vision ones etc, to handle that.

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DocM

It was too foggy for good footage, and winds were too probably too high for a dronecam.

Sounds like the grid fins got it to the ASDS just fine, but landing velocity controls need work. They have plenty of opportunities to refine it this year.

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PaulRocket

I'd call this a huge success although elon sounds a bit disappointed in his tweets. I heard that dscovr will have legs but no landing, anyone know more? They might not be able to fix the barge before the next attempt?

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DocM

No word yet on how much deck gear needs replacing, but Musk said the ship is OK. I doubt they'd attach legs if a landing wasn't being planned.

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malenfant

Well the worst-case was they'd miss the target or hit it and sink it. So nice compromise ;-)

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DocM

Oil leak in the grid fin hydraulics,

@elonmusk

Grid fins worked extremely well from hypersonic velocity to subsonic, but ran out of hydraulic fluid right before landing.

Upcoming flight already has 50% more hydraulic fluid, so should have plenty of margin for landing attempt next month.

Am super proud of my crew for making huge strides towards reusability on this mission. You guys rock!

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Unobscured Vision

Something I was thinking about as they did SECO and Dragon Separation (and afterwards). It appears they were watching how the unspent fuel was moving around in the tank in microgravity, and I suspect how much fuel was left over also .. perhaps they are gathering data about what they need to do to recover the second stage? That's the next logical step, and probably it's already "part of the plan".

 

As for having enough fuel to do a controlled return like they want to do with S1, I'm not so sure if that will work here.

 

[EDIT] Cut my own post short. Heh.

 

As I was saying, there are a few ways to recover the Falcon S2. The most economical (but the one with the highest degree of risk) is a free return where the gradual decay of its' orbit combined with some maneuvers could do the job. The return procedure, as I outline below, would still need to be done, but would require less resources. That would take weeks, and I doubt SpaceX would go for that.

 

The other could be increasing the fuel capacity in the S2 in conjunction with using a single or multi-stage Retro-Rocket package to cancel the orbital velocity. The Retros would deal with the orbital velocity, then again to slow the descent rate to prevent damage to the S2 (which is why they would need to be multi-stage). Once down to the altitude where the S1 would be, they could follow the procedure (tweaked for the S2, obviously, due to weight and aerodynamic differences) using the S2's primary engine and a second landing site. And we know SpaceX can do it on one engine because Grasshopper used a single engine for many of it's flights. Apples and Oranges, I know .. ;)

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DocM

A short gas thruster burp will settle the propellants. No big deal and already done before engine restarts.

My takeaway on this,

1) squash whatever bug is leaking the grid fins hydraulic fluid

2) this was like a night carrier deck landing with a rookie pilot and only 2 wires. They'll get better at it.

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Unobscured Vision

Oh yeah. They've got that figured out already. Very talented group of people over there.

 

The mission isn't even a day old and they're already making improvements for the hardware for the next flight. It's an example of passion, dedication, and outright giving a good golly gosh about what you're doing. :yes:

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PaulRocket

Well that confirms that they will land on dscovr. Do you really think the hydraulic fluid was leaking? Maybe it wasn't a closed cycle a closed cycle and their tanks were empty. That would make sense since he said they would add 50% more hydraulic fluid.

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flyingskippy

The hydraulics aren't closed loop on the F9. They are open to save on mass. When the fluid runs through the actuator, it is just dumped overboard. Adding a bigger tank will solve the problem like Musk has said.

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Unobscured Vision

I still don't see the real benefit of the open-loop system beyond a modest weight savings. And by the time they add the extra fluid for the next mission, they're around the same weight as a closed-loop is, but with a waste/loss factor -- which cuts into the profit margin, however slight. SpaceX needs to watch the books too. ;)

 

Just go with a closed loop system, build in some redundancy to cover failure scenarios, tweak accordingly, and test it for worthiness then get the flight cert. It's slightly heavier, but far more reliable, and it will save money in the long run.

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DocM

Now we know why it ran out of hydraulic fluid - its an open system, not closed.

@elonmusk:

@alankerlin Hydraulics are usually closed, but that adds mass vs short acting open systems. F9 fins only work for 4 mins. We were ~10% off.

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DocM

A user on reddit was on the KSC Causeway and caught the upper portions of the F9 S1 re-entry and deceleration burns before it went below the horizon.

1b10086fa7b9dd806b8ac8c743e9b607.jpg

Zoom

1f47b90b5f8d1f0181ca815636b7f313.jpg

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DocM

Yup, that's the 1st stage deceleration burn.

Can't say if they'll release footage.

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DocM

Dragon captured at ISS. Moving into position to berth.

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DocM

Got images of the crash landing. One from the launch video, one leaked, one from Musk and a couple I processed in grayscale to better show the toppling booster and a still deployed grid fin.

935a12dc074fdf3d9365fa44b9460a43.jpg

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120c8d7d252049efdda33647ddd1a547.jpg

d85aa3195e337a6a3166f91f1c2cb18b.jpg

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DocM

Looks like after the grid fins ran dry it was naturally off course, then the engine slewed it will in at a ~45

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bguy_1986

I thought it landed on the edge of the barge?  The second picture you posted makes it look like it was almost dead center (except not vertical).  How accurate was it?

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