Author Topic: Fairing reuse  (Read 523986 times)

Offline Mariusuiram

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Re: Fairing reuse
« Reply #460 on: 06/06/2016 06:33 AM »
Why not just use JPADS and land the fairings on their own ASDS. The 10,000 lb version is already called DragonFly. Could be confusing, but their heart's in the right place.   ::)

https://en.wikipedia.org/wiki/Joint_Precision_Airdrop_System
http://www.militaryaerospace.com/articles/2014/04/computer-parachute-airdrop.html

From reading their brochures, the 10k version is only accurate to 250 m while the smaller (2k?) version is only accurate to 150 m. Thats reasonably tight, but nowhere near tight enough to land on any vessel at sea.

From what I can tell, the smaller version should be enough as each fairing half will have its own system.

Offline JamesH65

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Re: Fairing reuse
« Reply #461 on: 06/06/2016 09:41 AM »
I wonder is small winglets on the fairings (perhaps retractable during launch) would enable them to 'fly', converting some vertical to horizontal velocity, should, give more accuracy to the landing point, and perhaps even ability to 'crash' land in to netting or similar on an ASDS. Would weigh less than a parachute I suspect.

Effectively, make the fairing a steerable lifting body.

Offline Kaputnik

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Re: Fairing reuse
« Reply #462 on: 06/06/2016 01:00 PM »
Another slightly out-there idea: the fairing's biggest weakness will be the lack of stiffness once separted into halves.
It would be an interesting little engineering project to design a strut would somehow not get in the way of the payload, but following fairing jettison would deploy to span the width of the fairing half and brace it again.
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Offline rpapo

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Re: Fairing reuse
« Reply #463 on: 06/06/2016 01:06 PM »
Another slightly out-there idea: the fairing's biggest weakness will be the lack of stiffness once separted into halves.
It would be an interesting little engineering project to design a strut would somehow not get in the way of the payload, but following fairing jettison would deploy to span the width of the fairing half and brace it again.
Even so, we have now multiple examples of the fairing surviving reentry and impact into the ocean.  It seems to be stiff enough as it is.  IMHO, what is needs is some sort of passive or active attitude control, with and without air flowing past.  If it can be kept on an even keel (rounded surface down, nose forward), it should have a relatively low terminal velocity.

A weight around one-third back from the nose should give it passive aerodynamic stability.
« Last Edit: 06/06/2016 01:13 PM by rpapo »
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Offline cscott

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Re: Fairing reuse
« Reply #464 on: 06/06/2016 01:53 PM »


Even so, we have now multiple examples of the fairing surviving reentry and impact into the ocean. 

We have multiple examples of *pieces* of the fairing being discovered after falling in the ocean.  Getting down intact has certainly not been shown.

Offline kevin-rf

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Re: Fairing reuse
« Reply #465 on: 06/06/2016 02:44 PM »
Do we know what the bottle necks in fairing production are? If it is the autoclave, then expanding production could be very expensive.
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Offline envy887

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Re: Fairing reuse
« Reply #466 on: 06/06/2016 03:27 PM »
Why not just use JPADS and land the fairings on their own ASDS. The 10,000 lb version is already called DragonFly. Could be confusing, but their heart's in the right place.   ::)

https://en.wikipedia.org/wiki/Joint_Precision_Airdrop_System
http://www.militaryaerospace.com/articles/2014/04/computer-parachute-airdrop.html

From reading their brochures, the 10k version is only accurate to 250 m while the smaller (2k?) version is only accurate to 150 m. Thats reasonably tight, but nowhere near tight enough to land on any vessel at sea.

From what I can tell, the smaller version should be enough as each fairing half will have its own system.

That's 150 to 250 FEET, which is 50-75 meters, which is close to the deck size of a ASDS. More barges?

Offline Lar

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Re: Fairing reuse
« Reply #467 on: 06/06/2016 03:29 PM »
I thought we separated the "here's how SpaceX COULD do reuse" from "here's concrete information about what they actually are doing" so we had two threads. But maybe I'm imagining that...
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Offline Bubbinski

Re: Fairing reuse
« Reply #468 on: 06/19/2016 02:31 AM »
Did SpaceX attempt a fairing recovery on the Eutelsat/ABS mission?
I'll even excitedly look forward to "flags and footprints" and suborbital missions. Just fly...somewhere.

Offline cscott

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Re: Fairing reuse
« Reply #469 on: 06/19/2016 02:41 AM »
No evidence that I could see: no visible RCS from the fairing after separation, no abnormal dallying of Go Searcher at sea.  Both the Go * ships appear to have headed straight back to port.

This isn't to claim there is any evidence that fairing recovery *wasn't* attempted: the fairing halves were only very briefly visible from the S1/S2 rocket cams, and a failed recovery attempt would probably also have resulted in Go Searcher having nothing to do.  I'm just saying there is no public evidence either way, at least that I know of, and I was looking for it.
« Last Edit: 06/27/2016 08:39 PM by cscott »

Offline Adriano

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Re: Fairing reuse
« Reply #470 on: 06/25/2016 06:19 AM »
I think the fairing can be reassembled as follows. The fairing is divided in three equal sections (process symmetrical and more stable than with two sections). The tree parts are connected with hinges and weak springs. the central section has spacers keeping the necessary distance from the load during the process. The process begins with the un latching of the two side sections and starting moving them apart with a spring released by the latch or similar. When the two side sections have completed a 90 degree rotation, the springs in the hinges begin to slow their motion. The inertia of the moving side sections is transmitted to the center section that will be dragged away from the load. When the three sections are clear from the load, the hinge springs will revert the motion of the side sections that will start closing. When the two side sections fully close, a latch will anchor them and the fairing is fully reassembled!

Offline Jim

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Re: Fairing reuse
« Reply #471 on: 06/25/2016 10:26 AM »
I think the fairing can be reassembled as follows. The fairing is divided in three equal sections (process symmetrical and more stable than with two sections). The tree parts are connected with hinges and weak springs. the central section has spacers keeping the necessary distance from the load during the process. The process begins with the un latching of the two side sections and starting moving them apart with a spring released by the latch or similar. When the two side sections have completed a 90 degree rotation, the springs in the hinges begin to slow their motion. The inertia of the moving side sections is transmitted to the center section that will be dragged away from the load. When the three sections are clear from the load, the hinge springs will revert the motion of the side sections that will start closing. When the two side sections fully close, a latch will anchor them and the fairing is fully reassembled!

Asymmetrical separation isn't going to work.  There are aeroloads and thrust.   It can't remain attached at the base while parts start rotating

Offline RAN

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Re: Fairing reuse
« Reply #472 on: 08/11/2016 10:37 PM »
I was recently at a tour of SpaceX Hawthorne and my guide offered information on fairing recovery.

He cautioned that it was still early, but one method of interest for recovery would be to use a large semi-inflated bag to cushion the landing.  He described it like a larger version of "bounce bags" that you might find at a summer camp.

Offline Robotbeat

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Re: Fairing reuse
« Reply #473 on: 08/12/2016 07:57 PM »
I was recently at a tour of SpaceX Hawthorne and my guide offered information on fairing recovery.

He cautioned that it was still early, but one method of interest for recovery would be to use a large semi-inflated bag to cushion the landing.  He described it like a larger version of "bounce bags" that you might find at a summer camp.
They cost about $1000 online for a 3m by 7m one, so you could buy a thousand of them for a million dollars and place them in a 100m by 200m grid. Should be able to hit that with a guided parasail.
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Offline meekGee

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Re: Fairing reuse
« Reply #474 on: 08/12/2016 09:19 PM »
I was recently at a tour of SpaceX Hawthorne and my guide offered information on fairing recovery.

He cautioned that it was still early, but one method of interest for recovery would be to use a large semi-inflated bag to cushion the landing.  He described it like a larger version of "bounce bags" that you might find at a summer camp.
They cost about $1000 online for a 3m by 7m one, so you could buy a thousand of them for a million dollars and place them in a 100m by 200m grid. Should be able to hit that with a guided parasail.

Air bags not carried by the fairings?  There's a concept...

Like that skydiver that jumped into a net instead of using a parachute...   That'd be funny.

So who knows, giant autonomous station-keeping air bags... ASDB! 

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Offline oiorionsbelt

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Re: Fairing reuse
« Reply #475 on: 08/12/2016 09:59 PM »
I was recently at a tour of SpaceX Hawthorne and my guide offered information on fairing recovery.

He cautioned that it was still early, but one method of interest for recovery would be to use a large semi-inflated bag to cushion the landing.  He described it like a larger version of "bounce bags" that you might find at a summer camp.
They cost about $1000 online for a 3m by 7m one, so you could buy a thousand of them for a million dollars and place them in a 100m by 200m grid. Should be able to hit that with a guided parasail.
This is not elegant.

Offline envy887

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Re: Fairing reuse
« Reply #476 on: 08/12/2016 10:01 PM »
I mentioned landing on pre-positioned airbags upthread.  A big challenge would be getting a 50m radius deck full of bags out in the middle of the Atlantic.

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Re: Fairing reuse
« Reply #477 on: 08/12/2016 10:10 PM »
They’ve got 2 tug ships going out there all the time that aren’t towing anything.  Strap the bags together, put some water in the bottom of them so they won’t blow around too easy with something that makes drag at the backend so they can pull straight.  Add a little generator for compressor/lights and there you go.

Offline meekGee

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Re: Fairing reuse
« Reply #478 on: 08/12/2016 10:11 PM »
I mentioned landing on pre-positioned airbags upthread.  A big challenge would be getting a 50m radius deck full of bags out in the middle of the Atlantic.

If they do, then you credit for predicting an incredibly unlikely solution that unless I'd heard it from SpaceX, I'd discount really quickly as "it will never happen".

You know, like barges.

My money is still on something that goes up and down with the fairing, weight penalty and all.
« Last Edit: 08/12/2016 10:11 PM by meekGee »
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Offline envy887

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Re: Fairing reuse
« Reply #479 on: 08/12/2016 10:31 PM »
They’ve got 2 tug ships going out there all the time that aren’t towing anything.  Strap the bags together, put some water in the bottom of them so they won’t blow around too easy with something that makes drag at the backend so they can pull straight.  Add a little generator for compressor/lights and there you go.

A giant inflatable raft, huh? That's brilliant. 8)

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