Author Topic: Fairing reuse  (Read 613297 times)

Offline Mark K

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Re: Fairing reuse
« Reply #1860 on: 12/12/2018 09:32 pm »
I wonder how much "reuse" might need to be qualified in that case. How much of what's in the interior of the fairing would be damaged by salt water spray getting all over it? Do we know enough publicly to take a stab at that?

Wouldn't that have happened in any seas if caught in a net anyway? There will be salt water spray all over that thing even if caught in a net. I always wondered about that.

Offline deruch

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Re: Fairing reuse
« Reply #1861 on: 12/13/2018 12:34 am »
Also it will have exhaust products deposited on it, inside and out, from its fall past the lit and burning MVac regardless of whether it was caught in a net or not.  So, from a cleanliness perspective, it wouldn't surprise me to learn that SpaceX was always going to be giving them a thorough cleaning.  As long as the water exposure/immersion isn't damaging the structures or any kept interior components, it probably doesn't matter that much.  But I guess we'll see how it all plays out going forward.  After they deal with them for a while, SpaceX may decide that fishing them out of the drink isn't sufficient and re-examine other recovery methods, etc. 
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Online photonic

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Re: Fairing reuse
« Reply #1862 on: 01/08/2019 07:14 am »
Finally a video of a recovery attempt of a fairing dropped by a helicopter!

https://twitter.com/SpaceX/status/1082469132291923968

Very close, but it seems that it is hard to catch even in quiet seas. To me it looks that Mr. Steven can easily catch up with and match the forward speed of the parachute, but it might lack in ability to quickly move sideways if there are some low level winds that move it off track. My armchair idea would be to improve the controls of the parachute to aggressively correct for any sideways movements, and let Mr. Steven worry about the forward direction.

The splashdown is anyhow extremely gentle, and should leave the inside pretty dry if the waves are small. The island seen at 0:15 seems San Clemente.
« Last Edit: 01/08/2019 07:31 am by photonic »

Online Cheapchips

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Re: Fairing reuse
« Reply #1863 on: 01/08/2019 07:22 am »

Tom Mueller's reply to the tweet. ;D

I know it's only a test fairing, but something flew off it at the 30 second mark when it was swinging wildly.

Offline su27k

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Re: Fairing reuse
« Reply #1864 on: 01/08/2019 07:31 am »
Seems a ship navigation/control problem, if the ship performs the right turn a few meters early it would be able to catch the fairing. Maybe they should consider letting computer autopilot run the intercept.

Offline Lars-J

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Re: Fairing reuse
« Reply #1865 on: 01/08/2019 07:58 am »
My armchair idea would be to improve the controls of the parachute to aggressively correct for any sideways movements, and let Mr. Steven worry about the forward direction.

Parachute quickly moving to the side? That’s all? :D

Well if you come up with a solution to that, you can have instant employment at any parachute manufacturer in the world.

Online kevinof

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Re: Fairing reuse
« Reply #1866 on: 01/08/2019 09:28 am »
I think the problem is the boat they are using. Being a long waterline it will be hard to turn quickly and if the parachute deviates at all in the last seconds the boat doesn't have a chance to react.  All this in a flat sea with little wind - can't see this as a solution that would work regularly.

Maybe just waterproof the fairing as much as possible and slash it.

Offline nacnud

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Re: Fairing reuse
« Reply #1867 on: 01/08/2019 09:34 am »
I wonder if you could get a more predictable flight path with a higher wing loading. Compensate for the faster decent rate with a softer net.

Maybe they already did this with the larger net.

Online Semmel

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Re: Fairing reuse
« Reply #1868 on: 01/08/2019 11:13 am »
I think the problem is the boat they are using. Being a long waterline it will be hard to turn quickly and if the parachute deviates at all in the last seconds the boat doesn't have a chance to react.  All this in a flat sea with little wind - can't see this as a solution that would work regularly.

Maybe just waterproof the fairing as much as possible and slash it.

The boat has to be long in order to be fast enough. Shorter boats would waste their energy by climbing their own bow wave.

Offline jded

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Re: Fairing reuse
« Reply #1869 on: 01/08/2019 11:21 am »
Maybe a hovercraft with directional fans would be quick & agile enough at the same time. But I have no idea how expensive a large custom made one could be.

Online kevinof

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Re: Fairing reuse
« Reply #1870 on: 01/08/2019 12:06 pm »
I would have gone for a cat - more speed for less waterline and also less displacement so easier to adjust direction.

I think the problem is the boat they are using. Being a long waterline it will be hard to turn quickly and if the parachute deviates at all in the last seconds the boat doesn't have a chance to react.  All this in a flat sea with little wind - can't see this as a solution that would work regularly.

Maybe just waterproof the fairing as much as possible and slash it.

The boat has to be long in order to be fast enough. Shorter boats would waste their energy by climbing their own bow wave.

Offline Jim

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Re: Fairing reuse
« Reply #1871 on: 01/08/2019 12:29 pm »
Maybe a hovercraft with directional fans would be quick & agile enough at the same time. But I have no idea how expensive a large custom made one could be.

Hovercraft aren't quick nor agile when it comes to maneuvering.  Also, parachute would be suck in to fans.

Offline racevedo88

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Re: Fairing reuse
« Reply #1872 on: 01/08/2019 01:22 pm »
It might be easier to do a helicopter snag recovery "Skyhook" of the fairing, don't need a fast boat just another barge of the same type as used for Falcon 9 landing and two helos. Helos take off from barge, skyhook the fairing, and bring the fairing back to the barge. Helos land on barge.

Offline wannamoonbase

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Re: Fairing reuse
« Reply #1873 on: 01/08/2019 01:27 pm »
I'm so happy to finally see a video of the fairing recovery attempt.  It's great to see that they are using the ship under power.

They are so close, they'll figure this out and I'm sure the data they collected will help them close the gap.

Very exciting and fairing recovery should be a massive advantage with the flight rate required to deploy Starlink.
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Offline Bananas_on_Mars

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Re: Fairing reuse
« Reply #1874 on: 01/08/2019 01:47 pm »
My approach would be a little different, similar to arial recovery, but with a ship. Maybe it adds to much mass, i'm quite sure they considered it. The fairing needs do deploy a reasonably long line with a sinker weight. The ship has a fork in front that's lightweight and can possibly be wider than what the current net is. It can catch the line and hook up the line to some winch. Now you've essentially turned the fairing into a kite/parasail, if the ship goes fast enough you can keep it aloft for a long time. That technique would remove "almost" 1 dimension from the 3D problem that catching a fairing is. 2D for ship positioning on the surface, 1D for time.
If you have a sink rate for the fairing of 2m/s and a 200m long line, you get a window of almost 100 seconds for a successful catch, and as an advantage you don't have to match the speed of the fairing, but can drive up "behind" it with greater speed.

Online meekGee

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Re: Fairing reuse
« Reply #1875 on: 01/08/2019 02:15 pm »
My approach would be a little different, similar to arial recovery, but with a ship. Maybe it adds to much mass, i'm quite sure they considered it. The fairing needs do deploy a reasonably long line with a sinker weight. The ship has a fork in front that's lightweight and can possibly be wider than what the current net is. It can catch the line and hook up the line to some winch. Now you've essentially turned the fairing into a kite/parasail, if the ship goes fast enough you can keep it aloft for a long time. That technique would remove "almost" 1 dimension from the 3D problem that catching a fairing is. 2D for ship positioning on the surface, 1D for time.
If you have a sink rate for the fairing of 2m/s and a 200m long line, you get a window of almost 100 seconds for a successful catch, and as an advantage you don't have to match the speed of the fairing, but can drive up "behind" it with greater speed.
Was gonna suggest exactly that.

Once snagged, winch it down, and you can then control the direction of travel too to minimize wave/wind impact.

Fwiw, the winch can be located on the parachute, so that they don't have to move the leader wire from the catch-hook to the winch, or to combine the two mechanisms.

EDIT: I have a deja vu all over again feeling here.  I think someone already proposed this like a year ago or more.
« Last Edit: 01/11/2019 08:36 pm by meekGee »
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Offline RobLynn

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Re: Fairing reuse
« Reply #1876 on: 01/08/2019 09:28 pm »
Seems lateral maneuverability and ship inertia is the problem.

I would suggest a specialised lightweight drone catcher:  triangular frame holding up net arms sitting on strong simple planing pontoons - essentially just wedges with outboard motors at trailing thick end (similar to off shore power boats) under each corner.  Tow it to landing zone then release it to stay centred under fairing as it falls.  Would be light weight, maybe as little as 10-20 tonnes , so could accelerate and turn in any direction very quickly.   Could be built for a couple of million, which is likely worth it if there are still a few hundred million in fairings to be caught before Starship comes on line.
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Offline wannamoonbase

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Re: Fairing reuse
« Reply #1877 on: 01/10/2019 02:21 pm »
Is there an attempt to recover the fairings with tomorrow's Iridium launch?
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Offline fast

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Re: Fairing reuse
« Reply #1878 on: 01/10/2019 02:30 pm »
Why not add big inflatable bags to the fairing so it will never touch the water?

Offline wannamoonbase

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Re: Fairing reuse
« Reply #1879 on: 01/10/2019 05:21 pm »
Why not add big inflatable bags to the fairing so it will never touch the water?

Way back in history when they started the fairing recovery discussion I was thinking of something like that.  Maybe it's weight or complication.

But, now with Mr Steven getting so close to being able to catch it, I have ot think that it's just easier if they catch it, that it never touch water or have the risk of hitting water.  But also, waves, the video and pictures we've seen the ocean always looks smooth as glass.  That won't always be true.
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