Author Topic: Fairing reuse  (Read 551408 times)

Offline Swoopert

Re: Fairing reuse
« Reply #1520 on: 04/12/2018 03:40 PM »
Some information on page 77-78 of Draft Environmental Assessment for Issuing a Reentry License to SpaceX for Landing the Dragon Spacecraft in the Gulf of Mexico contains information to the parachute used in the fairing recovery that some of you might find interesting.

64/113 ft2 drogues with 1782/3000 ft2 canopies with 42-50ft line lengths! They are not messing around small canopies! The best guesstimate I can find for the mass of a fairing half is 875kg (several sites have the full fairing at 1750kg), which puts the wing-loading on those parafoils at a distinctly un-sporty 1.08 and 0.64 lbs/ft2 respectively, those things are going to be floaty with a very slow to negative ground-speed in off-shore wind conditions...and being so lightly loaded I would have thought are very susceptible to parasitic drag issues. Colour me surprised again...but my experience is all with sport parachutes...

For reference, the main canopy (loaded at 2.55) in my profile pic is the same size as their Type 2 Drogue (which is loaded at 17 lbs/ft2!).

Edit: to add wing-loadings
« Last Edit: 04/12/2018 04:24 PM by Swoopert »

Offline EnigmaSCADA

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Re: Fairing reuse
« Reply #1521 on: 04/12/2018 07:40 PM »
Elon posted a new picture from the landed Iridium-5 fairing on twitter:

Quote
Elon Musk (repyling to @Teslerati)
Oh yeah, forgot to mention it actually landed fine, just not on Mr Steven

https://twitter.com/elonmusk/status/980647734888681472

Looks like new, but at least some of the foam got wet.
Looks like the hull of a boat just sitting there on the water. Just integrate an outboard motor and drive it home!

Offline aero

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Re: Fairing reuse
« Reply #1522 on: 04/13/2018 01:43 AM »
Elon posted a new picture from the landed Iridium-5 fairing on twitter:

Quote
Elon Musk (repyling to @Teslerati)
Oh yeah, forgot to mention it actually landed fine, just not on Mr Steven

https://twitter.com/elonmusk/status/980647734888681472

Looks like new, but at least some of the foam got wet.
Looks like the hull of a boat just sitting there on the water. Just integrate an outboard motor and drive it home!

Just keep the parafoil from collapsing and sail it home!
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Online deruch

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Re: Fairing reuse
« Reply #1523 on: 04/13/2018 02:32 AM »
At the nose of the fairing for the TESS mission you can see the nozzle/outlet for the ACS thrusters used to maintain stability during reentry.
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Offline cscott

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Re: Fairing reuse
« Reply #1524 on: 04/13/2018 10:03 AM »
Some information on page 77-78 of Draft Environmental Assessment for Issuing a Reentry License to SpaceX for Landing the Dragon Spacecraft in the Gulf of Mexico contains information to the parachute used in the fairing recovery that some of you might find interesting.

64/113 ft2 drogues with 1782/3000 ft2 canopies with 42-50ft line lengths! They are not messing around small canopies! The best guesstimate I can find for the mass of a fairing half is 875kg (several sites have the full fairing at 1750kg), which puts the wing-loading on those parafoils at a distinctly un-sporty 1.08 and 0.64 lbs/ft2 respectively, those things are going to be floaty with a very slow to negative ground-speed in off-shore wind conditions...and being so lightly loaded I would have thought are very susceptible to parasitic drag issues. Colour me surprised again...but my experience is all with sport parachutes...

For reference, the main canopy (loaded at 2.55) in my profile pic is the same size as their Type 2 Drogue (which is loaded at 17 lbs/ft2!).

Edit: to add wing-loadings
What influence would extreme altitude or extreme speed have, if any?  Perhaps the fact that the parachutes are not operating at steady state but in fact actively decelerating the load raises the wing loading to a more typical value, at least until terminal velocity is reached?  IIRC the stage 1 return doesn't reach terminal velocity until a quite low altitude.  Maybe there's a way to dump some of the excess chute area once they've reached terminal velocity---or perhaps trying to find the compromise between appropriate loading at initial entry and appropriate loading at sea level just before landing is what is making recovery so challenging.

Certainly recent recoveries are consistent with the idea that the chutes are successful in getting the fairing down to low altitude, but then they get so "floaty" that it's real hard to catch them on Mr Steven.

Offline swervin

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Re: Fairing reuse
« Reply #1525 on: 04/19/2018 04:25 AM »
And word on fairing survival down to an ocean landing for the TESS mission?

Offline FutureSpaceTourist

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Re: Fairing reuse
« Reply #1526 on: 04/21/2018 08:08 AM »
And word on fairing survival down to an ocean landing for the TESS mission?

Quote
That, my friends, appears to be a complete half fairing on board GO Pursuit. Quick grab off my preview screen. Some of the Falcon 9 has arrived at Port Canaveral #SpaceXFleet

https://twitter.com/julia_bergeron/status/987589035102298113

Offline FutureSpaceTourist

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Re: Fairing reuse
« Reply #1527 on: 04/21/2018 08:45 AM »
A better shot:

Quote
GO Pursuit, with what appears to be a complete fairing half on deck, arrived into Port Canaveral approx. 3:15 am EDT this morning. In a few short hours we should be seeing OCISILY being led in by Hawk and GO Quest after cruise ships are safely docked. #SpaceXFleet @SpaceX

https://twitter.com/julia_bergeron/status/987610215884484613
« Last Edit: 04/21/2018 08:45 AM by FutureSpaceTourist »

Offline swervin

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Re: Fairing reuse
« Reply #1528 on: 04/21/2018 09:31 AM »
Great, thx for sharing. They’re getting better...

Does anyone have an informed opinion on the effects of salt water on these fairings? Landing them safely is a great beginning in proving the concept, but I would think the investment in the craft to catch them was required to avoid salt water... or may now be reconsidered if these are reusable without the ‘catchers mit’?

Splinter

Offline FutureSpaceTourist

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Re: Fairing reuse
« Reply #1529 on: 04/21/2018 11:28 AM »
Great shot in daylight by @marekcyzio:

Quote
Looks like it #Tess #Falcon9 #SpaceX

https://twitter.com/marekcyzio/status/987652390143881217
« Last Edit: 04/21/2018 11:46 AM by FutureSpaceTourist »

Offline speedevil

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Re: Fairing reuse
« Reply #1530 on: 04/21/2018 11:37 AM »
Great, thx for sharing. They’re getting better...

Does anyone have an informed opinion on the effects of salt water on these fairings?
Saltwater in principle can be managed. The structure is in principle waterproof,and suitable materials can be found for any accessories, or those replaced.
Hitting a very solid ocean, with a flexible structure, at an unpredictable orientation and speed, and perhaps having subsequent loading due to water inside moving in response to external wind and wave action, may impart very hard to model loads on the fairing, making it hard to reasonably assess if it's remained within its structural limits.

Or, it may be they know for certain that the impact is in the range where it could sustain damage.
If it may, then the question arises of how to develop and prove out a complete non-destructive test methodology, and possibly even repair.
This can be expensive.

Or maybe it was always going to be fine falling in the water, and the fairing recovery efforts were a smokescreen to cover S2 recovery practice.

To even start to answer the question, you'd need to know the exact construction, and load limits on the structure, and the actual impact speed in the water, and which way down it came.
Unfortunately problematic.


Offline MarekCyzio

Re: Fairing reuse
« Reply #1531 on: 04/21/2018 11:54 AM »
Slightly better view. Edit - sorry, still learning how to use new camera.
« Last Edit: 04/21/2018 11:58 AM by MarekCyzio »

Offline FutureSpaceTourist

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Re: Fairing reuse
« Reply #1532 on: 04/21/2018 12:01 PM »
I can’t quite work out from the shape of the tarpaulins if the fairing half is in pieces or if there’s more than one fairing half recovered?

Offline Johnnyhinbos

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Fairing reuse
« Reply #1533 on: 04/21/2018 12:06 PM »
I can’t quite work out from the shape of the tarpaulins if the fairing half is in pieces or if there’s more than one fairing half recovered?
I was thinking the same thing. What’s the OTHER thing under the tarp...?

Edit to add - this GO ship doesn’t have an A-frame. So if she was in the recovery area unsupported then the fairing was probably winched in through the transom, which is probably not overly good for the fairing either.
« Last Edit: 04/21/2018 12:08 PM by Johnnyhinbos »
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Offline DistantTemple

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Re: Fairing reuse
« Reply #1534 on: 04/21/2018 10:26 PM »
I can’t quite work out from the shape of the tarpaulins if the fairing half is in pieces or if there’s more than one fairing half recovered?
I was thinking the same thing. What’s the OTHER thing under the tarp...?

Edit to add - this GO ship doesn’t have an A-frame. So if she was in the recovery area unsupported then the fairing was probably winched in through the transom, which is probably not overly good for the fairing either.
We saw the one in LA that seemed in great condition (from a photo!) with its guts being ripped out (all the blocks/panels on the inside), and this one is haphazardly tarped, and probably roughly handled in recovery. These can't be intended for re-use, as they would have to be stripped to the shell, and then comprehensively examined with ultrasound or whatever is used to hunt for stress damage.
However since they land and float they are a hazard to navigation, and must be collected or sunk. And collection is easier once Go-pursuit has got to the location. I expect a few will end up as exhibits, but reflight will only happen to those that are properly "caught". 
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Online wannamoonbase

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Re: Fairing reuse
« Reply #1535 on: 04/22/2018 03:28 PM »
Seems that they are trying to figure out para-foil deployment.  Actually recovering the fairing in a usable condition will come very quickly after they can predict and control the flight path. 

When we see them flying hardware on both halves we'll know they are getting close.

My 2 cents: I bet they are only a few more attempts (iterations) from success.

Edit: I'm dying to see video of the return flight, parafoil deployment and attempt to land in the net.  More Sci-Fi in real life.
« Last Edit: 04/22/2018 03:47 PM by wannamoonbase »
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Offline speedevil

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Re: Fairing reuse
« Reply #1536 on: 04/22/2018 04:08 PM »
When we see them flying hardware on both halves we'll know they are getting close.

My 2 cents: I bet they are only a few more attempts (iterations) from success.
I wonder if we'll end up with S2 and fairing recovery competing for boats.

Offline Rebel44

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Re: Fairing reuse
« Reply #1537 on: 04/22/2018 09:08 PM »
When we see them flying hardware on both halves we'll know they are getting close.

My 2 cents: I bet they are only a few more attempts (iterations) from success.
I wonder if we'll end up with S2 and fairing recovery competing for boats.

Getting more boats is relatively easy/cheap (considering cost of fairing and value or recovered 2nd stage)

Offline Barrie

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Re: Fairing reuse
« Reply #1538 on: 04/22/2018 09:19 PM »
I can’t quite work out from the shape of the tarpaulins if the fairing half is in pieces or if there’s more than one fairing half recovered?
I was thinking the same thing. What’s the OTHER thing under the tarp...?

Edit to add - this GO ship doesn’t have an A-frame. So if she was in the recovery area unsupported then the fairing was probably winched in through the transom, which is probably not overly good for the fairing either.

Maybe they recovered both halves, but the one equipped for recovery is in better shape, as one would expect

Offline speedevil

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Re: Fairing reuse
« Reply #1539 on: 04/23/2018 06:15 AM »
Getting more boats is relatively easy/cheap (considering cost of fairing and value or recovered 2nd stage)
I was wondering if S2 recovery attempts were started before fairing recovery had been nailed, and a second/third boat bought. Clearly this would not be a usual operation going forward.

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