Author Topic: Fairing reuse  (Read 551559 times)

Online RDoc

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Re: Fairing reuse
« Reply #860 on: 04/03/2017 08:52 PM »
It will be fascinating to see what they use for terminal and landing control.

I suppose that if sports parachutists can land within a few centimeters, a robot system can as well, but my understanding is that military cargo drops using GPS guided automated systems (JPAD) are more like 70m. That's pretty big for a sea going bouncy castle.

Offline savuporo

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Re: Fairing reuse
« Reply #861 on: 04/03/2017 08:58 PM »
..t my understanding is that military cargo drops using GPS guided automated systems (JPAD) are more like 70m.

They were. JPADs seem to have evolved significantly since the initial operational capability almost 10 years ago now, specifically around landing with high precision in difficult terrain.
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Offline iamlucky13

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Re: Fairing reuse
« Reply #862 on: 04/04/2017 03:13 AM »
Very cool to see they recovered a half, even if visibly quite damaged.

No indication the fairing landing was the "fate" referred to earlier, but the successful re-flight was absolutely thrilling,  and seemed in the brief interview immediately afterwards to have left Elon breathless.

Offline deruch

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Re: Fairing reuse
« Reply #863 on: 04/04/2017 03:27 AM »
Loads of pics from Reddit user aftersteveo https://imgur.com/gallery/qa2rB
Looks like quite a bit of damage! About right for a first try, though, and the real accomplishment is getting them to a pre-determined place where they could be recovered.
I haven't seen any info on how close they came to hitting their target.  I'm trying to get an estimated accuracy for this first attempt.  Clearly they were close enough so that the recovery boat could still get to it before it sank.  Which seems a significant achievement in addition to the feat of it just surviving to sea level, but maybe they are quite buoyant in salt water and this isn't so incredible.  And we know that they got to it at least within the amount of time it took for Elon to mention it at the post-launch briefing (any estimates on how much time this was?).  Hopefully, we'll get some info on just how close they came to the bullseye soon.  I still remember how awesome it was when they added the grid fins to the 1st stage and hit the ASDS on the next try. 
« Last Edit: 04/04/2017 03:27 AM by deruch »
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Offline cppetrie

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Re: Fairing reuse
« Reply #864 on: 04/04/2017 03:44 AM »
Very cool to see they recovered a half, even if visibly quite damaged.

Unfortunately we have no way of knowing how the damage in the pictures was sustained. On descent? On contact with the water? While in the water floating waiting to be picked up? While bringing aboard? Note they don't have the proper lifting equipment on the vessel to lift it out of the water. As others noted, it was probably dragged aboard likely resulting in significant damage.

If it made it through descent without damage and landed where they intended it to land then the effort was wildly successful. If true, all they need is a proper catch vessel (the so called "bouncy house") and they have themselves a fairing recovery system. My guess is that this attempt proved out their concept, and the next attempts will be with catch vessel (perhaps only one for now) and any refinements their data suggests are needed. Once they land a few on a catch vessel they'll be brought back for extensive structural testing and evaluation to determine viability for reuse. With the number of launches they will have coming up in which to make iterations, I won't be the least bit surprised if they are ready to fly reused (flight-proven) fairings on the FH demo or another flight before the end of the year.

Online meekGee

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Re: Fairing reuse
« Reply #865 on: 04/04/2017 06:07 AM »
So bouncy house...   On top of a boat, or towed behind it?

Station-keeping, or full-steam into the wind?
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Offline cppetrie

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Re: Fairing reuse
« Reply #866 on: 04/04/2017 06:35 AM »
So bouncy house...   On top of a boat, or towed behind it?

Station-keeping, or full-steam into the wind?
My guess is inflatable cushion on a second ASDS. Depending on accuracy it may be possible to catch both fairings on the same ship. Something on a ship would mean no need to offload at all while at sea. Dragging an inflatable raft of some sort seems unwieldy and problematic. Offloading so raft can be deflated means using a crane, and getting people aboard an inflatable raft in anything other than completely calm seas to secure lift cables seems super sketchy. Also, something being dragged just seems to variable in course and speed to reliably land on. Stationary boat with station-keeping thrusters seems like a better target. Yeah, I think drone ship barge with inflatable pillow on the surface. Inflate. Catch. Deflate. Secure. Tow it home.

Online JamesH65

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Re: Fairing reuse
« Reply #867 on: 04/04/2017 11:42 AM »
So bouncy house...   On top of a boat, or towed behind it?

Station-keeping, or full-steam into the wind?
My guess is inflatable cushion on a second ASDS. Depending on accuracy it may be possible to catch both fairings on the same ship. Something on a ship would mean no need to offload at all while at sea. Dragging an inflatable raft of some sort seems unwieldy and problematic. Offloading so raft can be deflated means using a crane, and getting people aboard an inflatable raft in anything other than completely calm seas to secure lift cables seems super sketchy. Also, something being dragged just seems to variable in course and speed to reliably land on. Stationary boat with station-keeping thrusters seems like a better target. Yeah, I think drone ship barge with inflatable pillow on the surface. Inflate. Catch. Deflate. Secure. Tow it home.

i agree some sort of drone chip with cushions. There is a problem with catching two halves though. Don't want one landing on the other.  Two drones? But of course they don't need to be as tough as the ASDS, so will be a lot cheaper. Could also be manned I suspect, as the fairings are light and have nothing explosive on board. Just need a hardened shelter for personnel.  I like the idea of a large catamaran based platform.

Offline rsdavis9

Re: Fairing reuse
« Reply #868 on: 04/04/2017 12:05 PM »
Is there any advantage of the cat with cushion matching horizontal velocity with the fairing when landing?
Also given a good eye(from captain) or computers it could make up for targeting accuracy.
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Offline sevenperforce

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Re: Fairing reuse
« Reply #869 on: 04/04/2017 12:21 PM »
Is there any advantage of the cat with cushion matching horizontal velocity with the fairing when landing?
Also given a good eye(from captain) or computers it could make up for targeting accuracy.
The horizontal velocity will be known ahead of time, so this seems like a good idea. Though it might be greater than what the cat can pull.

Offline Robotbeat

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Re: Fairing reuse
« Reply #870 on: 04/04/2017 12:36 PM »
Did he really say bouncy house? I said that upthread a ways.
"Bouncy castle" and he said it with a straight face and no one else laughed. 😂

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Yeah, but "bouncy castle" is funny! :)
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Offline Kaputnik

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Re: Fairing reuse
« Reply #871 on: 04/04/2017 01:00 PM »
Is there any advantage of the cat with cushion matching horizontal velocity with the fairing when landing?
Also given a good eye(from captain) or computers it could make up for targeting accuracy.
The horizontal velocity will be known ahead of time, so this seems like a good idea. Though it might be greater than what the cat can pull.

I'm in two minds about this one. There are too many assumptions at work to call it either way.
What speed will the fairings be flying in at? Faster speeds mean smaller chutes and better response to wind shifts and gusts (a fairing half has a lot of surface area for its mass). But slower speeds give better landing survivability.
Boats that are dead in the water can have a horrible motion. Steaming slowly into the waves/swell/wind can help a lot, but going too fast makes for violent slamming.

I think there could be merit in a large inflatable raft (bouncy castle) that is simply allowed to drift with the wind. The wind will be affecting the fairing to a similar degree, not identical though owing to wind gradient and the water drag on the raft.
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Offline speedevil

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Re: Fairing reuse
« Reply #872 on: 04/04/2017 01:18 PM »
I haven't seen any info on how close they came to hitting their target.  I'm trying to get an estimated accuracy for this first attempt.  Clearly they were close enough so that the recovery boat could still get to it before it sank.  Which seems a significant achievement in addition to the feat of it just surviving to sea level, but maybe they are quite buoyant in salt water and this isn't so incredible.
http://www.bbc.co.uk/news/uk-england-cornwall-34941462
It indeed floats long-term.

This is a fairing which bobbed along just under/on the surface all the way to the UK.

Though this method of recovery is probably not useful for reflight :)
« Last Edit: 04/04/2017 01:18 PM by speedevil »

Online JamesH65

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Re: Fairing reuse
« Reply #873 on: 04/04/2017 01:48 PM »
I've been pondering, and that fact that the fairings are coming down under parachute will probably mean that whatever they land on will need to be informing them of the wind conditions at the landing site. They will need to come in heading in to wind, so they need to know the exact wind direction to do so. This means comms from the ground to the fairing, which isn't done on the 1st stage since it comes in so fast it doesn't need to worry about wind and can compensate quickly for that it does encounter. I don't think a parachute will have the same level and speed of control, the descent is also much slower so more time to be affected by the wind.






Offline rsdavis9

Re: Fairing reuse
« Reply #874 on: 04/04/2017 01:53 PM »
will have the same level and speed of control, the descent is also much slower so more time to be affected by the wind.

And more time for a fast boat to move under it. :)
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Offline Basto

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Re: Fairing reuse
« Reply #875 on: 04/04/2017 02:20 PM »
I have been studying the photos and am curious what people are basing their claims of damage on.

The detail in the photos did not seem to indicate damage to me.  Just wondering what I am missing.

Online ellindsey

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Re: Fairing reuse
« Reply #876 on: 04/04/2017 02:24 PM »
The edge of the fairing facing the camera, sticking out from under the blue tarp, is very clearly broken off.  On some of the photos you can see skin peeled back away from the center of the fairing half.  I don't know if this damage occurred while it was in the water or during the process of pulling it onto the boat, but there is clear mechanical damage.

Online JamesH65

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Re: Fairing reuse
« Reply #877 on: 04/04/2017 02:42 PM »
will have the same level and speed of control, the descent is also much slower so more time to be affected by the wind.

And more time for a fast boat to move under it. :)

Not sure how close to the coast these things can be flown, but out in the Atlantic, the rather large waves might be an issue with anything too fast, unless it's really big.

Offline Basto

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Re: Fairing reuse
« Reply #878 on: 04/04/2017 02:45 PM »
The edge of the fairing facing the camera, sticking out from under the blue tarp, is very clearly broken off.  On some of the photos you can see skin peeled back away from the center of the fairing half.  I don't know if this damage occurred while it was in the water or during the process of pulling it onto the boat, but there is clear mechanical damage.

I went back through all of the photos and am seeing the peeled back shell now. Sometimes hard to get the fine details when looking on my phone. Thanks!

Offline speedevil

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Re: Fairing reuse
« Reply #879 on: 04/04/2017 03:52 PM »
The edge of the fairing facing the camera, sticking out from under the blue tarp, is very clearly broken off.  On some of the photos you can see skin peeled back away from the center of the fairing half.  I don't know if this damage occurred while it was in the water or during the process of pulling it onto the boat, but there is clear mechanical damage.
I'm unsure, but the dimensions look off to me, and don't work unless there are several bits, or it's not all there.

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