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SpaceX Vehicles and Missions => SpaceX Reusable Rockets Section => Topic started by: dcporter on 06/01/2015 08:41 PM

Title: Fairing reuse
Post by: dcporter on 06/01/2015 08:41 PM
An interesting hint at fairing reusability in a tweetback from Elon:

https://twitter.com/elonmusk/status/605460768516014080
Title: Re: Fairing reuse
Post by: meekGee on 06/01/2015 08:56 PM
I didn't believe this when the first hints showed up, but I guess it's for real...

Well, if anyone can pull this off right now, it's SpaceX.
Title: Re: Fairing reuse
Post by: ClayJar on 06/01/2015 09:17 PM
Apparently three of them found the fairing piece:

Kevin (twitter (https://twitter.com/kpe)) posted a full set of high-res original images on his dropbox (https://www.dropbox.com/sh/vzvobzwhwdz6mdd/AADl7VIEFMrPaGMS2r3rR-XAa).
Grier (twitter (https://twitter.com/grierallen)) said they were sending GoPro/card back to SpaceX.
Nate (twitter (https://twitter.com/natedapore)) posted another high-res shot on ow.ly (http://ow.ly/i/b3Bcl/original).

(Should someone attach the photos for posterity?)
Title: Re: Fairing reuse
Post by: Comga on 06/01/2015 09:30 PM
Can anyone explain the details seen in the images?
That's a GoPro camera in an aerospace grade housing?
Whatt about the access port, the hose, those wavy metal straps, the ball tipped long arm, and the short rounded arm?
I am not sure this is really OT for reuseable farings.  This one is definitely not reuseable, although the camera might be.
Title: Re: Fairing reuse
Post by: Elmar Moelzer on 06/01/2015 09:35 PM
I am not sure this is really OT for reuseable farings.  This one is definitely not reuseable, although the camera might be.
IMHO it is on topic, because Musk wants to use the information gathered from it for their future reusable fairings.
Title: Re: Fairing reuse
Post by: ClayJar on 06/01/2015 09:53 PM
Can anyone explain the details seen in the images?
That's a GoPro camera in an aerospace grade housing?
Whatt about the access port, the hose, those wavy metal straps, the ball tipped long arm, and the short rounded arm?
I am not sure this is really OT for reuseable farings.  This one is definitely not reuseable, although the camera might be.
The big hoses must be for environmental control (air conditioning the insides of the fairing before launch), as I can't think of anything else that would make sense.  The wavy metal straps are brackets for the large hoses, which were attached with zip ties.  (The remaining longer hose piece is still attached to some of them with the same zip ties that are present in some of the now empty brackets.)

The long arm with a ball joint at one end has a hinge at the remaining attachment, and the short round heavy-duty eye appears to contain a bearing.  Obviously related to moving parts (for fairing sep?).

And it's two GoPro camera/data logger housings, actually.  One is clearly visible, and the second is by the two big hoses near the side (the ball-tipped arm nearly hits it).  We've only seen occasional glimpses inside the fairing during launch video, but they apparently are kitted out for more than we see (which is, of course, a gross understatement).  I can only imagine that if the GoPro cameras continued rolling after fairing sep, having them back with full-resolution imagery and so on could provide some quite handy information.
Title: Re: Fairing reuse
Post by: FutureSpaceTourist on 06/01/2015 10:09 PM
(Should someone attach the photos for posterity?)

I inadvertently created a duplicate thread. Here are the initial photo's I uploaded.

Still can't get my head around that it's worth the effort to re-use fairings!
Title: Re: Fairing reuse
Post by: Arcas on 06/01/2015 10:28 PM
Why not just attach the fairings to hinges, and snap them shut after releasing payload instead of blowing them off.
Title: Re: Fairing reuse
Post by: DMeader on 06/01/2015 10:33 PM
Why not just attach the fairings to hinges, and snap them shut after releasing payload instead of blowing them off.

They separate to reduce weight. At that point in the ascent they are no longer needed to protect the payload. However, the vehicle is still under power, significantly before the payload is released.
Title: Re: Fairing reuse
Post by: meekGee on 06/01/2015 10:37 PM
Still can't get my head around that it's worth the effort to re-use fairings!

This is circumstantial evidence that cost/launch is headed way down.

I know they're expending the second stage which is more expensive than a fairing, but still somehow they decided this is important enough to bother.  odd.
Title: Re: Fairing reuse
Post by: Robotbeat on 06/01/2015 11:34 PM
Why not just attach the fairings to hinges, and snap them shut after releasing payload instead of blowing them off.
Because fairings are attached to the upper stage and so you'd have to bring it all away up to orbit. You could attach the fairing to the first stage like an atlas V (an idea I like and toyed with once when designing an RLV) but then the fairing would have to be at least twice as big.
Title: Re: Fairing reuse
Post by: sojourner on 06/02/2015 01:29 AM
Maybe the "reuse" part of the tweet was just Elon being Flippant?
Title: Re: Fairing reuse
Post by: Jim on 06/02/2015 01:47 AM

1.  What about the access port,
2.  the hose, those wavy metal straps,
3.  the ball tipped long arm,
4.   and the short rounded arm?


1.  For spacecraft access
2.  AC ducts
3.  Push rod for fairing sep
4.  fairing sep system
Title: Re: Fairing reuse
Post by: Elmar Moelzer on 06/02/2015 01:48 AM
I have always wondered why they wait a full minute after the separation of the second stage for the separation of the fairing. Is there anything preventing them from doing that event earlier? If not, how early could it theoretically happen? Given the heavy SpaceX fairing, an earlier fairing separation could IMHO mean a bit of extra performance (and for reuse getting it down closer to the launch site might be beneficial too).
Title: Re: Fairing reuse
Post by: Jim on 06/02/2015 01:53 AM
I have always wondered why they wait a full minute after the separation of the second stage for the separation of the fairing. Is there anything preventing them from doing that event earlier? If not, how early could it theoretically happen? Given the heavy SpaceX fairing, an earlier fairing separation could IMHO mean a bit of extra performance (and for reuse getting it down closer to the launch site might be beneficial too).

Yes there is something.  There is a requirement for the free molecular heating to be below a certain level. The level is determined by spacecraft requirements.
Title: Re: Fairing reuse
Post by: bstrong on 06/02/2015 03:29 AM
Still can't get my head around that it's worth the effort to re-use fairings!

This is circumstantial evidence that cost/launch is headed way down.

I know they're expending the second stage which is more expensive than a fairing, but still somehow they decided this is important enough to bother.  odd.

I wonder if they've come to the conclusion that maintaining hazard zones like they do today is going to prevent them from achieving super-high launch rates

Assuming they can someday convince the FAA/USAF that the risk of dropping first stages on unsuspecting boaters is comparable to the risk of planes falling out of the sky on them, uncontrolled fairing descent could be the only reason for keeping the hazard zones around.
Title: Re: Fairing reuse
Post by: Elmar Moelzer on 06/02/2015 04:23 AM
Yes there is something.  There is a requirement for the free molecular heating to be below a certain level. The level is determined by spacecraft requirements.
You mean heating from the air (as minimal as it may be at that altitude)?
Is there an ballpark altitude for that? Just curious.
Title: Re: Fairing reuse
Post by: Galactic Penguin SST on 06/02/2015 05:16 AM
Yes there is something.  There is a requirement for the free molecular heating to be below a certain level. The level is determined by spacecraft requirements.
You mean heating from the air (as minimal as it may be at that altitude)?
Is there an ballpark altitude for that? Just curious.

More than 100 km high in most cases - usually closer to 110-130 km.
Title: Re: Fairing reuse
Post by: Jim on 06/02/2015 10:54 AM

You mean heating from the air (as minimal as it may be at that altitude)?
Is there an ballpark altitude for that? Just curious.

It is a function of vehicle velocity also well as air density.  So, there isn't a specific altitude.
Title: Re: Fairing reuse
Post by: MattMason on 06/02/2015 12:42 PM
Why not just attach the fairings to hinges, and snap them shut after releasing payload instead of blowing them off.

Looks like, historically, full separation of fairings is the safer plan, too. Apollo 7's S-IVB adapter panels simply opened like flower petals. But they opened asymmetrically and concerned mission planners that future LM extractions or the CSM would be jeopardized. So fairing jettison was the way to go to avoid collisions or obstructions.

I don't think a recloseable fairing system would work. First, how would it safely move off the vehicle? That would require it to open up like a clamshell to provide payload clearance and then be propelled upward like a launch escape system tower, and then commanded to close again.

Even if the fairing was jettisoned whole, like the pulling the cover to the tip of a pen, it would need to be larger in diameter to add a little extra space to avoid brushing the payload as it exits. In either case, the fairing is heavier with the jettison jets and separation must be perfect or the payload or LV is in jeopardy.

None of my fanciful speculations will stop a company from figuring out an idea to make that work, however.
Title: Re: Fairing reuse
Post by: deruch on 06/02/2015 01:47 PM
Full res posted to dropbox:  https://www.dropbox.com/sh/vzvobzwhwdz6mdd/AADl7VIEFMrPaGMS2r3rR-XAa

Images rehosted at:
https://imgur.com/a/SyfRN

Galleries from previous finds of SpaceX fairing pieces-
Found in Hawaii:  https://imgur.com/a/g06A2

Found in Cape Hatteras, NC: https://imgur.com/a/0bo6s


edit: updated original gallery to include the full set of pictures from the dropbox posting and added the previous galleries for comparison.
Title: Re: Fairing reuse
Post by: Comga on 06/02/2015 02:05 PM

1.  What about the access port,
2.  the hose, those wavy metal straps,
3.  the ball tipped long arm,
4.   and the short rounded arm?

1.  For spacecraft access
2.  AC ducts
3.  Push rod for fairing sep
4.  fairing sep system

Thanks. Can you be more descriptive or point to a reference?
The "push rod" is clear
Is the "fairing step system" something that was held to a matching piece on the other half with an explosive bolt?
Do AC ducts attach to payloads or just direct the purge flow at specific points?  My assumption was that clean dry gas just flowed into the fairing and out some small port.
Any description of how the access port is opened or held closed in those images?
Title: Re: Fairing reuse
Post by: Jim on 06/02/2015 02:15 PM

1.  Is the "fairing step system" something that was held to a matching piece on the other half with an explosive bolt?
2.  Do AC ducts attach to payloads or just direct the purge flow at specific points?  My assumption was that clean dry gas just flowed into the fairing and out some small port.
3.  Any description of how the access port is opened or held closed in those images?


1.  Yes, but the release mechanism is not explosive.  (Spacex has an aversion to them)
2.  The ducts lead to the top of the fairing where the air "showers" over the payload.
3.  Just standard fasteners (screws)
Title: Re: Fairing reuse
Post by: Donosauro on 06/02/2015 04:05 PM
I don't know how conventional China Great Wall's payload fairings are, but this chapter of one of their user manuals shows both the input port for conditioned air and a number of exhaust ports:

http://www.cgwic.com/LaunchServices/Download/manual/Chapter%204%20Payload%20Fairing.pdf
Title: Re: Fairing reuse
Post by: Kabloona on 06/02/2015 04:35 PM
Info from the GoPro camera/data logger housing photos:

For the top level assembly:

P/N 00195412-501 Rev A
"Assy, GoPro Housing, Data Logger, Fair" (ie fairing)
Serial numbers 1 and 15 on the two housings shown in the photos

Quick Response code on the label for inventory control/build logs: SPXGUY4

For the cover plate:

P/N 00195412-002 Rev A
PO 387118 (probably a purchase order number, indicating outsourced, not made in-house)

Assembled with NAS6703 bolts, standard aerospace grade made of A286 CRES.

Nothing surprising, but a few interesting tidbits, like the use of GoPro cameras.
Title: Re: Fairing reuse
Post by: starsilk on 06/02/2015 04:38 PM
Still can't get my head around that it's worth the effort to re-use fairings!

This is circumstantial evidence that cost/launch is headed way down.

I know they're expending the second stage which is more expensive than a fairing, but still somehow they decided this is important enough to bother.  odd.

we need to think of the long game. it may not be terribly economic to reuse them on the F9 (or perhaps even a loss), but they are learning how to do it for the MCT when the fairing is going to be MUCH bigger and more valuable.

MCT is presumably going to be big enough and expensive enough that it simply has to be fully reused, otherwise it's not economic - except for a rare government launch perhaps where they can afford to throw away hundreds of millions of dollars of hardware.
Title: Re: Fairing reuse
Post by: speedevil on 06/02/2015 07:59 PM
<snip of why fairing is jetisoned after staging, not at>
Yes there is something.  There is a requirement for the free molecular heating to be below a certain level. The level is determined by spacecraft requirements.

In principle, a very, very light structure - perhaps even inflated could be added inside for a shield in the minute or so afterwards.
A quick calculation indicates Q at this point is well under 1Pa.
(I uses ~M6 and 100km as ballpark staging point).

That doesn't of course answer the awkward point of how you'd get the fairing down to the first stage, and attach it. (swelling dramatically the fairing doesn't seem sane)

If there was an easy way to join the fairing halves again, they'd be a lot more structurally robust, and in principle would have quite a low terminal velocity and weight allowing catch by copter.
Title: Re: Fairing reuse
Post by: Elmar Moelzer on 06/02/2015 08:30 PM

You mean heating from the air (as minimal as it may be at that altitude)?
Is there an ballpark altitude for that? Just curious.

It is a function of vehicle velocity also well as air density.  So, there isn't a specific altitude.
Thanks, makes sense! So how does that fit in with the suggestion by some to make the fairing part of the first stage (I think someone said that Atlas does that) which would mean fairing separation about a minute earlier?
Does Atlas do the staging later in the flight envelope?
Title: Re: Fairing reuse
Post by: RanulfC on 06/02/2015 09:37 PM
Check me on this,

It looks like the thing broke up on impact with the ocean so it would seem "reuse" would be on the order of making that event survivable. That however does nothing for the range restrictions issues.

Probably a "bad" idea but what about having the fairing separate along one side and then eject side-ways so that it could close up for reentry?

(And what's this about a "fairing" for the MCT?)

Randy
Title: Re: Fairing reuse
Post by: dcporter on 06/03/2015 05:23 AM
Check me on this,

It looks like the thing broke up on impact with the ocean so it would seem "reuse" would be on the order of making that event survivable. That however does nothing for the range restrictions issues.

Probably a "bad" idea but what about having the fairing separate along one side and then eject side-ways so that it could close up for reentry?

(And what's this about a "fairing" for the MCT?)

Randy

If the problem is landing rather than falling, how would clamming back up help? I'd think that would reduce drag, increasing the speed left at impact.
Title: Re: Fairing reuse
Post by: Jim on 06/03/2015 01:44 PM

Thanks, makes sense! So how does that fit in with the suggestion by some to make the fairing part of the first stage (I think someone said that Atlas does that) which would mean fairing separation about a minute earlier?
Does Atlas do the staging later in the flight envelope?

For the 5m, the fairing comes off before 2nd stage sep.
For the 4m, it comes off after 2nd stage start.
Most fairings on other vehicles come off after 2nd stage start.
Title: Re: Fairing reuse
Post by: Jim on 06/03/2015 01:45 PM

In principle, a very, very light structure - perhaps even inflated could be added inside for a shield in the minute or so afterwards.


Why?  That is the main purpose of the fairing, so why duplicate it and make the system more complex?
Title: Re: Fairing reuse
Post by: Elmar Moelzer on 06/03/2015 02:50 PM
For the 5m, the fairing comes off before 2nd stage sep.
For the 4m, it comes off after 2nd stage start.
Most fairings on other vehicles come off after 2nd stage start.
Thanks, Jim!
So what speaks against an F9 fairing that always comes off at or shortly before second stage separation? It is obviously possible to do it, since Atlas is doing it with the 5m fairing.
Title: Re: Fairing reuse
Post by: RanulfC on 06/03/2015 03:08 PM
If the problem is landing rather than falling, how would clamming back up help? I'd think that would reduce drag, increasing the speed left at impact.

Drag should be about the same with both halves being rejoined you have only a single "piece" rather than two to track/control to landing. The halves should also be more supporting together than when separated.
I'm just throwing an idea out but frankly I don't see "fairing-reuse" as being serious.

Randy
Title: Re: Fairing reuse
Post by: Jim on 06/03/2015 04:30 PM

So what speaks against an F9 fairing that always comes off at or shortly before second stage separation? It is obviously possible to do it, since Atlas is doing it with the 5m fairing.

Spacecraft requirements for the environment. 

There is a "blackout" period around stage separation that fairing separation is usually not performed.  The vehicle goes into attitude hold in preparation for booster shutdown.  After shutdown, the vehicle is not accelerating and so fairing sep can't really be done.  There are transients and attitude excursions associated with second stage coast and ignition, so fairing sep is set off few seconds (5 or so after the engine is steady state)

Atlas V first stage burn out is around 240 seconds. 
Fairing come off at 270 seconds for 4 meter (during 2nd stage burn)
Fairing come off at 200 seconds for 5 meter (during 1st stage burn)

Velocity has a role in determining environments, a 5m mission is going to be slower for a given movement is the timeline vs a 4m.

F9 first stage burn out is around 150 seconds.
Falcon 9 fairing comes off at 210 seconds

So, the fairing on F9 isn't going to come off earlier. 
Title: Re: Fairing reuse
Post by: guckyfan on 06/03/2015 04:34 PM
So what speaks against an F9 fairing that always comes off at or shortly before second stage separation? It is obviously possible to do it, since Atlas is doing it with the 5m fairing.

Falcon 9R stages very early. So the payload still needs some protection, I would assume.
Title: Re: Fairing reuse
Post by: meekGee on 06/03/2015 09:40 PM
So what speaks against an F9 fairing that always comes off at or shortly before second stage separation? It is obviously possible to do it, since Atlas is doing it with the 5m fairing.

Falcon 9R stages very early. So the payload still needs some protection, I would assume.

I think F9R also flies a more lofted trajectory, which should in principle help to drop the fairing earlier.
Title: Re: Fairing reuse
Post by: douglas100 on 06/03/2015 10:01 PM
I think a re-usable fairing only makes economic and technical sense as part of a re-usable upper stage, maybe like  the Kistler K-1. Bottom line, a re-usable fairing is a non-starter for current vehicles. The extra complexity for little economic return makes it not worth it IMHO.

Since a fairing carried to orbit is going to cause a large payload hit, it only makes sense for a much larger re-usable vehicle.

Title: Re: Fairing reuse
Post by: nadreck on 06/03/2015 10:04 PM
I think a re-usable fairing only makes economic and technical sense as part of a re-usable upper stage, maybe like  the Kistler K-1. Bottom line, a re-usable fairing is a non-starter for current vehicles. The extra complexity for little economic return makes it not worth it IMHO.

Since a fairing carried to orbit is going to cause a large payload hit, it only makes sense for a much larger re-usable vehicle.

And if the initial investment in each fairing is $1M and the cost to recover and recommission is $500,000 you wouldn't do it?
Title: Re: Fairing reuse
Post by: douglas100 on 06/03/2015 10:11 PM
I think a re-usable fairing only makes economic and technical sense as part of a re-usable upper stage, maybe like  the Kistler K-1. Bottom line, a re-usable fairing is a non-starter for current vehicles. The extra complexity for little economic return makes it not worth it IMHO.

Since a fairing carried to orbit is going to cause a large payload hit, it only makes sense for a much larger re-usable vehicle.

And if the initial investment in each fairing is $1M and the cost to recover and recommission is $500,000 you wouldn't do it?

Not unless you could demonstrate these numbers are real.
Title: Re: Fairing reuse
Post by: nadreck on 06/03/2015 10:17 PM
I think a re-usable fairing only makes economic and technical sense as part of a re-usable upper stage, maybe like  the Kistler K-1. Bottom line, a re-usable fairing is a non-starter for current vehicles. The extra complexity for little economic return makes it not worth it IMHO.

Since a fairing carried to orbit is going to cause a large payload hit, it only makes sense for a much larger re-usable vehicle.

And if the initial investment in each fairing is $1M and the cost to recover and recommission is $500,000 you wouldn't do it?

Not unless you could demonstrate these numbers are real.

I obviously was not succinct. Please perform the thought experiment: imagine that each fairing costs $1M to produce and the amortized cost of the equipment to make them reusable, the use of the craft to do the recovery, and the recommissioning expense adds up to $500,000.  Now having considered that, would you go ahead with the project to recover them?
Title: Re: Fairing reuse
Post by: deruch on 06/04/2015 02:57 AM
The issue for SpaceX is their ability to make enough fairings.  They are currently ramping up their flight rate very quickly.  Even with a decent number of future launches being Dragons (i.e. no fairing), they are still going to need a whole lot more of them per year in the near future.  What is their manufacturing capability?  How expandable is that capability?  What is the cost comparison between having to open additional production lines vs. investment to make them reusable?  etc. 
Title: Re: Fairing reuse
Post by: meekGee on 06/04/2015 04:19 AM
The issue for SpaceX is their ability to make enough fairings.  They are currently ramping up their flight rate very quickly.  Even with a decent number of future launches being Dragons (i.e. no fairing), they are still going to need a whole lot more of them per year in the near future.  What is their manufacturing capability?  How expandable is that capability?  What is the cost comparison between having to open additional production lines vs. investment to make them reusable?  etc.

The constellation might require as much as one launch per week.

I'm surprised though that fairing manufacturing is not dwarfed by second stage manufacturing.  I guess it isn't...
Title: Re: Fairing reuse
Post by: douglas100 on 06/04/2015 08:16 AM

I obviously was not succinct. Please perform the thought experiment: imagine that each fairing costs $1M to produce and the amortized cost of the equipment to make them reusable, the use of the craft to do the recovery, and the recommissioning expense adds up to $500,000.  Now having considered that, would you go ahead with the project to recover them?

All you're saying is, if it saves money, wouldn't you go ahead and do it? In my original post I gave the opinion that recovering the fairing from current vehicles (specifically F9)  wouldn't save money and therefore I wouldn't do it.

By all means argue the point, but please back it up with facts or a technical argument rather than pulling numbers out of the air and calling them a "thought experiment."
Title: Re: Fairing reuse
Post by: CJ on 06/04/2015 08:46 AM
I think a re-usable fairing only makes economic and technical sense as part of a re-usable upper stage, maybe like  the Kistler K-1. Bottom line, a re-usable fairing is a non-starter for current vehicles. The extra complexity for little economic return makes it not worth it IMHO.

Since a fairing carried to orbit is going to cause a large payload hit, it only makes sense for a much larger re-usable vehicle.

My take; SpaceX wouldn't be working on fairing recovery for the F9 and FH unless they could see an economic reason to do so.

Going by what they've said, they have a limit on how many fairings they can produce per year. I assume that they could increase their capacity, but doing so would cost a significant amount of money. That $, plus the per unit cost, must be high enough to make reuse attractive to them. The fact that they are considering it makes it near certain that it's economically attractive - assuming it works like they think.   

If (and it's a big if) the fairing halves survive up until impact in a reusable state, my guess is that recovery isn;t all that hard, theoretically, nor would it be much of a mass penalty. For example, add a GPS beacon and a small drogue on a long line, and use a helicopter to grab it. Hrmmm... fly the helicopters off an ASDS?

 
Title: Re: Fairing reuse
Post by: Robotbeat on 06/04/2015 12:18 PM
If you're flying, say, 40 or 50 times per year, it may indeed make sense to reuse the fairing.
Title: Re: Fairing reuse
Post by: LouScheffer on 06/04/2015 02:06 PM

All you're saying is, if it saves money, wouldn't you go ahead and do it? In my original post I gave the opinion that recovering the fairing from current vehicles (specifically F9)  wouldn't save money and therefore I wouldn't do it.

By all means argue the point, but please back it up with facts or a technical argument rather than pulling numbers out of the air and calling them a "thought experiment."

Here's a rough guess I made when fairing recovery was only in L2, which I've fixed since I had the wrong launch rate for Ariane 5:

From "RUAG Space wins major Ariane 5 payload fairing contract " http://www.ruag.com/space/media/media-releases/news/ruag-space-wins-major-ariane-5-payload-fairing-contract/c1d44492a47610accba20f7849f17843/ , the contract is for $100M (one swiss franc is about a dollar), signed in 2014, and runs through 2019.  Assuming they did not wait until the last minute to sign this, I'm guessing through 2016 was in the prior contract.  Then this would be roughly 18 fairings (6 per year for 2017, 2018, 2019), or about $5-6M each.

SpaceX makes them in-house, so they might already have a cost advantage.  But if they can recover and refurbish a fairing for $1M, then they've got a $5M per flight advantage over Ariane and Atlas V  (which use the RUAG fairings).  When you are trying to drive the cost down to a few 10s of millions, that helps considerably.   To be competitive on cost, Atlas VI and Ariane VI will now need to be cheaper than SpaceX, not just equivalent.
Title: Re: Fairing reuse
Post by: nadreck on 06/04/2015 02:09 PM

I obviously was not succinct. Please perform the thought experiment: imagine that each fairing costs $1M to produce and the amortized cost of the equipment to make them reusable, the use of the craft to do the recovery, and the recommissioning expense adds up to $500,000.  Now having considered that, would you go ahead with the project to recover them?

All you're saying is, if it saves money, wouldn't you go ahead and do it? In my original post I gave the opinion that recovering the fairing from current vehicles (specifically F9)  wouldn't save money and therefore I wouldn't do it.

By all means argue the point, but please back it up with facts or a technical argument rather than pulling numbers out of the air and calling them a "thought experiment."

Actually the post I was responding to suggested it saved only a little money and was not worth it.  I work in an industry where it is worth effort of some participants to organize their schedule of activity of several different $5M capital projects just to save about $100,000 on each.  Other participants don't fine tune this way. Yet cutting the capital cost is worth it as long as it doesn't increase risk significantly.

Given that your opinion as most recently expressed is that it will cost more to recover a fairing than to manufacture a new one then my question was irrelevant.
Title: Re: Fairing reuse
Post by: JasonAW3 on 06/04/2015 02:23 PM
     I might be a bit off base here, but it occures to me that the Fairing reuse may not be just for launches from Earth.

     On Mars, fairings are dumped for each lander.  This is material that has cost quite a bit of money to launch to Mars.  As larger landers will likely require larger heat shields and fairings, recovery of these could be QUITE useful as building materials.  As heatshields have a curved surface, epoxying a number of them together to create a geodesic dome, would not be all that difficult and could provide fairly decent surface storage facilities after a few landings.  Any uppe fairings could also be made somewhat curved or simply used as is, if the fairing is large enough.
Title: Re: Fairing reuse
Post by: douglas100 on 06/04/2015 02:23 PM

....Given that your opinion as most recently expressed is that it will cost more to recover a fairing than to manufacture a new one then my question was irrelevant.

That's right, that was my opinion, but LouScheffer's numbers give me pause.
Title: Re: Fairing reuse
Post by: douglas100 on 06/04/2015 02:38 PM

....If (and it's a big if) the fairing halves survive up until impact in a reusable state, my guess is that recovery isn't all that hard, theoretically, nor would it be much of a mass penalty. For example, add a GPS beacon and a small drogue on a long line, and use a helicopter to grab it. Hrmmm... fly the helicopters off an ASDS?

You've put your finger on one difficulty in your first sentence (my bold). Another would be the uncontrolled flight of the fairing halves before recovery. Details and trades, as ever...

However, assuming the helicopters can get to them in time, then mid air recovery makes sense. Suggest the ULA approach and use parafoils rather than drogues to avoid a high vertical velocity before capture.
Title: Re: Fairing reuse
Post by: Comga on 06/04/2015 03:49 PM
(snip).
Hmmm... fly the helicopters off an ASDS?

This was mentioned before, and makes a lot of sense.  You don't want to send helicopters out to sea to hover, burning fuel during any hold.  Better to cruise out onboard a ship, and wait to fire up until terminal coundown.  After capture, instead of a long trip to shore with the giant sail-like fairing half, it gets deposited on the deck. 
Not obvious whether it would be better to land the helos on the barge or fly back unburdened.  Is there enough room on one of these barges to launch two helicopters, or to land two helicopters AND the fairing halves.

The main rotors on the CH-47D are listed (http://147thhillclimbers.org/hill_site/pdf_file/Chinook%20Legacy-January%202014.pdf) as ~98' in length and ~61' in width.
Is the 175' wide by ~250' long deck big enough for landing (dockside or at sea) and take-off, even without hanging fairing halves?
Title: Re: Fairing reuse
Post by: baldusi on 06/04/2015 04:17 PM
     I might be a bit off base here, but it occures to me that the Fairing reuse may not be just for launches from Earth.

     On Mars, fairings are dumped for each lander.  This is material that has cost quite a bit of money to launch to Mars.  As larger landers will likely require larger heat shields and fairings, recovery of these could be QUITE useful as building materials.  As heatshields have a curved surface, epoxying a number of them together to create a geodesic dome, would not be all that difficult and could provide fairly decent surface storage facilities after a few landings.  Any uppe fairings could also be made somewhat curved or simply used as is, if the fairing is large enough.
First, that's too far into the future. And second, it would sem that the MCT would land and launch as a whole to/from Mars. This is for Earth only, and if the L2 con ops are realized, it would only work on Earth.
Title: Re: Fairing reuse
Post by: The Amazing Catstronaut on 06/04/2015 04:52 PM

Is the 175' wide by ~250' long deck big enough for landing (dockside or at sea) and take-off, even without hanging fairing halves?

Sure should be. Helicopters can manage to land (and take back off) on very small floating pads on objects less stable than the ASDS.

Edit: I wonder if SpaceX will rent their skycranes or purchase them? I'd be heading for the latter.
Title: Re: Fairing reuse
Post by: RanulfC on 06/04/2015 07:15 PM

All you're saying is, if it saves money, wouldn't you go ahead and do it? In my original post I gave the opinion that recovering the fairing from current vehicles (specifically F9)  wouldn't save money and therefore I wouldn't do it.

By all means argue the point, but please back it up with facts or a technical argument rather than pulling numbers out of the air and calling them a "thought experiment."

Here's a rough guess I made when fairing recovery was only in L2, which I've fixed since I had the wrong launch rate for Ariane 5:

From "RUAG Space wins major Ariane 5 payload fairing contract " http://www.ruag.com/space/media/media-releases/news/ruag-space-wins-major-ariane-5-payload-fairing-contract/c1d44492a47610accba20f7849f17843/ , the contract is for $100M (one swiss franc is about a dollar), signed in 2014, and runs through 2019.  Assuming they did not wait until the last minute to sign this, I'm guessing through 2016 was in the prior contract.  Then this would be roughly 18 fairings (6 per year for 2017, 2018, 2019), or about $5-6M each.

SpaceX makes them in-house, so they might already have a cost advantage.  But if they can recover and refurbish a fairing for $1M, then they've got a $5M per flight advantage over Ariane and Atlas V  (which use the RUAG fairings).  When you are trying to drive the cost down to a few 10s of millions, that helps considerably.   To be competitive on cost, Atlas VI and Ariane VI will now need to be cheaper than SpaceX, not just equivalent.

Uhm, the cost savings isn't as clear as that because recovery and refurbishment doesn't factor in having to make them (apparently) more robust in the first place as well as adding a recovery system. The fairings are going to fall well away from the first stage recovery vehicles so that requires another set of recovery vehicles and personnel which adds costs. (Assuming that Elon wasn't being flippant in the first place :) )

The uncontrolled nature of the falling fairings also adds up costs as you have to make the assumption that you will need a helicopter for each fairing half. "Fixing" that issue means added mass and complexity which increases construction costs and impacts payload and reduces the case for reusability in the first place. And you have to include the possibility that one or both fairing halves on any flight will end up being outside your recovery area and you "lose" them anyway with added (due to stationing the recovery vehicles and crews) instead of saved costs.

I'd see saving's range starting out lower around @$4million initially at best from the given information.

With a high enough flight rate the numbers might point towards reusability but it wouldn't seem so at present.
(Second stage efficiency and reusability would to me seem a higher priority)

Randy
Title: Re: Fairing reuse
Post by: jimbowman on 06/05/2015 09:48 PM
 https://www.youtube.com/watch?v=4_sLTe6-7SE
Title: Re: Fairing reuse
Post by: ClayJar on 06/05/2015 10:10 PM
Beautiful footage.  I suppose this means they got the GoPro cameras and cards from the guys who found the piece in the Bahamas.

Too bad we didn't get the special Extended Edition that goes all the way down.  I wonder what we'll get to see when they actually start active fairing recovery tests. :)
Title: Re: Fairing reuse
Post by: meekGee on 06/05/2015 10:58 PM
Finally, footage worthy of the background music...  :)
Title: Re: Fairing reuse
Post by: matthewkantar on 06/05/2015 11:20 PM
Video is really breath taking. What are the objects that keep showing up? Sun obviously. Moon? Second stage firing? other fairing half? Planets? Stars?

Matthew
Title: Re: Fairing reuse
Post by: Lars-J on 06/06/2015 03:09 AM
Video is really breath taking. What are the objects that keep showing up? Sun obviously. Moon? Second stage firing? other fairing half? Planets? Stars?

Matthew

Likely the second stage, and the other fairing half.
Title: Re: Fairing reuse
Post by: FutureSpaceTourist on 06/06/2015 03:56 AM
Yes, very cool video. It has it's own thread at http://forum.nasaspaceflight.com/index.php?action=profile;u=18754 (http://forum.nasaspaceflight.com/index.php?action=profile;u=18754).
Title: Re: Fairing reuse
Post by: Mariusuiram on 06/08/2015 08:09 AM
Not getting into "economics" here with Marginal Costs, etc, but keep in mind that cost comparisons should account for variable & fixed production costs (cost to build a fairing), CAPEX to expand or add a new factory as they grow, operational expenses of reuse / refurbishment operation, and R&D investment in figuring this out (adding GoPros to existing fairings, staff time, possibly adding RCS or foils or something to existing fairings)

Lets say Ariane pays $5 million per fairing and SpaceX does it for $2 million in blended cost at their current max run rate in their factory.

While its easy to ask, does the cost to produce outweigh the refurbishment cost, there is a a better hurdle to view.

SpaceX likely has a good deal on their current factory space and from photos appears to use it all in their production efforts. Additional expansion opportunities may be limited or may require new development that will be more expensive.

So ignoring the operational costs for a moment. If SpaceX needs to expand its fairing production into a neighboring facility that could involve a $10-15 million CAPEX for space and equipment. And moreso that might be space that could go to Stage II production expansion or Dragon expansion etc. So there could be a higher opportunity cost there.

That may be the decision driver right there. Even if operational and refurbishment costs eat up savings, avoiding growing their fixed asset and production base may justify the investment.

Assuming SpaceX achieves economies of scale, that investment in expansion should reduce cost per unit, so maybe fairing costs would drop to 1.5 million. But a recovery and refurbishment operation should likely achieve more savings, although that is dependent on assumptions (this would exclude R&D cost)

Overall analysis gets much more complicated but could be simplified as:
Option 1: Production Expansion
+ XX CAPEX for new facilities & equipment / - Small X in cost per unit via economies of scale / No change in operational costs of launch

Options 2: Reuse
+YY (possibly equal or likely less than XX) for R&D of reuse / - Large Y in cost per unit via reuse (making it a depreciating asset across # of uses) / + small/medium Z in operational launch costs for recovery / refurbish


Its all trades, but basically you are aiming to invest in R&D instead of facilities and get lower cost per launch overall for the fairing's activities. Of interest based on SpaceX's aspirations. If they hope to exponentially increase launch rate (ie 24 a year soon, 50 a year soonish and daily eventually), every step up would require another new investment in fairing production facilities. So a new facility gets them to 25 a year, but need another big CAPEX to go to 50-100 etc. Whereas if they figure out how to reuse, they can minimize new CAPEX and have a more stable R&D budget to continually improve fairing recovery / refurbishment. So a company only ever hoping to go to 25 launches a year, may see a bigger factory as suitable, but a company that wants to get into the hundreds should start figuring out reuse.

Similar argument for why they have to achieve reuse of the first stage.
Title: Re: Fairing reuse
Post by: Zed_Noir on 06/08/2015 10:32 AM
@Mariusuiram

SpaceX already expanded into some of the surrounding lots & buildings adjacent to their original Hawthorne facility. They are in need of of more floor space & parking space IMO. Especially if they stockpile bulky items like fairing & Falcon legs indoors.
Title: Re: Fairing reuse
Post by: iamlucky13 on 06/10/2015 02:13 AM
I'm surprised though that fairing manufacturing is not dwarfed by second stage manufacturing.  I guess it isn't...

Fairings probably are dwarfed by second stage. That doesn't meant that fairings can't become a supply choke point.

With aircraft, you'd think bolts would be dwarfed by engines, or landing gear, or some other large, expensive system. Yet, several months of the delays of the Boeing 787 were created simply by the inability of suppliers to ramp up production of certain types of fasteners they needed. Deliveries of the same plane are currently being screwed up waiting on seats.

Uhm, the cost savings isn't as clear as that because recovery and refurbishment doesn't factor in having to make them (apparently) more robust in the first place as well as adding a recovery system.

How much more robust? The pictures show fairly good overall condition, aside from being broken up. The extra hardware might be as simple as a light coating of TPS, a cold gas system to orient it for entry (assuming it can't passively orient before peak heating and/or pressure) and a way to protect it from hitting the water too hard (parachute or parachute + helicopter).

Quote
The fairings are going to fall well away from the first stage recovery vehicles so that requires another set of recovery vehicles and personnel which adds costs.

Agreed on that point. You wouldn't want them staging close to the 1st stage ground track anyways, for safety.

Quote
(Second stage efficiency and reusability would to me seem a higher priority)

I would assume SpaceX is working on both 2nd stage recovery and fairing recovery concurrently. 2nd stage almost certainly has the higher potential value, but fairing is potentially a lower hanging fruit.

I don't see any wires coming out of that GoPro mount that could have carried the data to an antenna for downlink, so I'm pretty well convinced SpaceX was hoping their camera (or cameras, over multiple launches) would be recovered, presumably so they could study how the fairing behaves during entry and when it breaks up.
Title: Re: Fairing reuse
Post by: Doesitfloat on 10/14/2015 03:50 PM
Just got notification of sale of 20 Italian HH-3F-Pelican aircraft.
from Wikipedia:

In 1965, U.S. Coast Guard ordered a version designated, HH-3F Sea King (more commonly known by its nickname "Pelican") for all-weather air-sea rescue.[2] The Pelican featured a search radar with a nose antenna radome offset to port,[1][4] and water landing capability.[2]

Italian Agusta built a S-61R variant, named AS-61R under license. Agusta produced 22 helicopters for the Italian Air Force.[2] The company claimed it could re-open the production line in 36 months to build additional AS-61 helicopters.[5]

So, it's a big amphibious helicopter.  Isn't this what you would want to catch fairings and or have crew close to ASDS.

edit: The notification is that Italy is selling the aircraft; not that they are sold.
Title: Re: Fairing reuse
Post by: Moe Grills on 12/22/2015 02:53 AM
Let me destroy a myth that has been passed off as a fact in recent years.

There is a persistent myth among many people, who should know better, that assume aircraft today and yesterday are and were nearly 100% reusable, when they are and were not.
First: a World War Two example: P51 Mustang fighters in that conflict flew off on long-range missions with COMPLETELY DISPOSABLE  fuel drop-tanks.
I won't even mention that all piston-engine aircraft after so many hours of flight, had to have their engines overhauled (many parts, pistons, etc., were disposed and replaced).
Today's passenger jets also need engine overhauls from time to time; not to mention that tires, brake pads, hydraulic components, etc. all get frequently replaced.
So why are some of you believing or dreaming of completely reusable spacecraft , when it will never happen? And doesn't need to happen to make space travel affordable?
Title: Re: Fairing reuse
Post by: JamesH on 12/22/2015 08:34 AM
Let me destroy a myth that has been passed off as a fact in recent years.

There is a persistent myth among many people, who should know better, that assume aircraft today and yesterday are and were nearly 100% reusable, when they are and were not.
First: a World War Two example: P51 Mustang fighters in that conflict flew off on long-range missions with COMPLETELY DISPOSABLE  fuel drop-tanks.
I won't even mention that all piston-engine aircraft after so many hours of flight, had to have their engines overhauled (many parts, pistons, etc., were disposed and replaced).
Today's passenger jets also need engine overhauls from time to time; not to mention that tires, brake pads, hydraulic components, etc. all get frequently replaced.
So why are some of you believing or dreaming of completely reusable spacecraft , when it will never happen? And doesn't need to happen to make space travel affordable?

Well, by your definition, even a car is not reusable....

It all comes down to the cost of 'reusability', whatever the definition. It's cheaper to refurb the engine on an airliner than build a new airliner.
Title: Re: Fairing reuse
Post by: Comga on 12/23/2015 03:41 AM
And I thought you people would be discussing whether there was a boat in the area where the fairings should have fallen, possibly looking for them, this being the Fairing Reuse thread.
Foolish me
Title: Re: Fairing reuse
Post by: mme on 12/23/2015 01:00 PM
Let me destroy a myth that has been passed off as a fact in recent years.

There is a persistent myth among many people, who should know better, that assume aircraft today and yesterday are and were nearly 100% reusable, when they are and were not.
First: a World War Two example: P51 Mustang fighters in that conflict flew off on long-range missions with COMPLETELY DISPOSABLE  fuel drop-tanks.
I won't even mention that all piston-engine aircraft after so many hours of flight, had to have their engines overhauled (many parts, pistons, etc., were disposed and replaced).
Today's passenger jets also need engine overhauls from time to time; not to mention that tires, brake pads, hydraulic components, etc. all get frequently replaced.
So why are some of you believing or dreaming of completely reusable spacecraft , when it will never happen? And doesn't need to happen to make space travel affordable?
I don't really understand the point of your post nor the myth you are "destroying."

SpaceX is actively looking into ways to recover and reuse the fairings.  This thread exists because of that effort.  SpaceX is concerned about being able to produce fairings fast enough if they achieve the sort of launch cadence that is their goal.  Also, the fairings cost a couple million dollars and SpaceX hopes to eventually get launch prices down to a point that a couple million dollars is noticeable.  The fact that there are some parts that are disposable, some will require replacement, and some will need repair is completely orthogonal to this thread.
Title: Re: Fairing reuse
Post by: cscott on 12/23/2015 02:11 PM
And I thought you people would be discussing whether there was a boat in the area where the fairings should have fallen, possibly looking for them, this being the Fairing Reuse thread.
Foolish me
That discussion is happening in the ASDS thread, where all the boat trackers hang out. Go Quest is believed to be on the hunt.

http://forum.nasaspaceflight.com/index.php?topic=36326.msg1463732.msg#1463732
Title: Re: Fairing reuse
Post by: CJ on 12/24/2015 05:30 AM
This might be far fetched, but I can't help but wonder if a path to fairing reuse might be a change in outer layer (to resist seawater damage), a small drogue chute, and a water-activated radio pinger to enable finding them. 

My guess is the hardest part would be coming up with a way to make the fairing structure (a composite honeycomb) resist seawater damage, without increasing mass.

As for Go Quest, it definitely appears that it was out there looking for something. It appears to be inbound for Canaveral now.
Title: Re: Fairing reuse
Post by: Kabloona on 12/24/2015 09:43 AM
Go Quest docked last night at Port Canaveral. Unfortunately timing was bad...she came in at night, and today is Christmas Eve, so few people will want to go over and take a look and see if she has any fairing halves on board...
Title: Re: Fairing reuse
Post by: Jim on 12/24/2015 04:22 PM
Fairings break up and don't come down in one piece.
Title: Re: Fairing reuse
Post by: Kabloona on 12/24/2015 05:04 PM
Fairings break up and don't come down in one piece.

With the GoPro cams and Elon's tweet in the first post of this thread, they're clearly looking at the possibility of recovering/reusing fairings at some point. This mission would have been a good one to try some recovery experiments on, though I don't know what method they might have in mind to keep the fairing intact.

If they didn't find an intact fairing half, at least they may have found a large piece with the GoPro cam on it.
Title: Re: Fairing reuse
Post by: OxCartMark on 12/24/2015 05:24 PM
Fairings break up and don't come down in one piece.

So do rockets if they're not designed to be reusable.
Title: Re: Fairing reuse
Post by: OxCartMark on 12/24/2015 05:26 PM
Fairings break up and don't come down in one piece.

Well, I'll give you this - I know you're right on one level because I saw it break into two pieces during the webcast.
Title: Re: Fairing reuse
Post by: kch on 12/24/2015 05:48 PM
Go Quest docked last night at Port Canaveral. Unfortunately timing was bad...she came in at night, and today is Christmas Eve, so few people will want to go over and take a look and see if she has any fairing halves on board...

Seems like it'd be pretty quiet there today ... might be a good time to go halve a look.  ;)
Title: Re: Fairing reuse
Post by: Comga on 12/26/2015 05:55 PM
Fairings break up and don't come down in one piece.

Well, I'll give you this - I know you're right on one level because I saw it break into two pieces during the webcast.

I wrote a long reply before realizing that your post is a lame joke missing the smiley face.
It did give me an unneeded excuse to rewatch the launch video.
As for Jim's comment, fairings did break up and come down in pieces.  First stages also fell in the ocean.
Unless that was Jim's idea of a bone-dry joke, too.
How could we tell?
Title: Re: Fairing reuse
Post by: cscott on 12/26/2015 07:10 PM
I'm pretty sure no one expects that Go Quest recovered a complete, intact, and reusable fairing from this mission.  But fairing fragments have washed up before, and Go Quest might have managed to locate some---or at least the piece which has the radio beacon and instrument package on it (if indeed some experiment of that sort was flown).
Title: Re: Fairing reuse
Post by: oiorionsbelt on 12/26/2015 07:49 PM
I'm pretty sure no one expects that Go Quest recovered a complete, intact, and reusable fairing from this mission.  But fairing fragments have washed up before, and Go Quest might have managed to locate some---or at least the piece which has the radio beacon and instrument package on it (if indeed some experiment of that sort was flown).
Go Quest would not be out looking for the fairing if they didn't intend to learn something from the pieces. The have found quite a few pieces already. What could have changed from the last mission to make them them want to go look for it?
 I'm not convinced GQ was looking for the fairing but if it was there must be something 'new' about this fairing.
Title: Re: Fairing reuse
Post by: Avron on 12/26/2015 08:04 PM
I'm pretty sure no one expects that Go Quest recovered a complete, intact, and reusable fairing from this mission.  But fairing fragments have washed up before, and Go Quest might have managed to locate some---or at least the piece which has the radio beacon and instrument package on it (if indeed some experiment of that sort was flown).
Go Quest would not be out looking for the fairing if they didn't intend to learn something from the pieces. The have found quite a few pieces already. What could have changed from the last mission to make them them want to go look for it?
 I'm not convinced GQ was looking for the fairing but if it was there must be something 'new' about this fairing.

might be looking for that GoPro https://www.youtube.com/watch?v=4_sLTe6-7SE
Title: Re: Fairing reuse
Post by: ugordan on 12/26/2015 08:07 PM
might be looking for that GoPro

For those awesome shots of pitch-black darkness?
Title: Re: Fairing reuse
Post by: Jakusb on 12/26/2015 08:22 PM

Fairings break up and don't come down in one piece.

You mean: they used to, until some all daring new entrant challenged all status quo, carefully build up in the last 40 years.... ;)
Title: Re: Fairing reuse
Post by: Avron on 12/26/2015 08:24 PM
might be looking for that GoPro

For those awesome shots of pitch-black darkness?

we don't know that, I would suspect some data gathering of the fairing behaviour with this new  vehicle.
Title: Re: Fairing reuse
Post by: Ixian77 on 12/26/2015 09:13 PM
Fairings could retract back down along side second stage skin, in six segments. Deploy payload.
Then, after nose mounted superdracos fire to reorient second stage, fairing redeploy to act as TPS for reentry. As superdracos fire to land second stage, fairing partial retractment to act as landing legs.

You're welcome.
Title: Re: Fairing reuse
Post by: cscott on 12/26/2015 10:06 PM
That ignores the rocket equation: the fairing is a substantial mass thus wants to separate from the payload at the earliest possible opportunity.
Title: Re: Fairing reuse
Post by: Comga on 12/26/2015 10:23 PM
Fairings could retract back down along side second stage skin, in six .....(snip)

You're welcome.
for nothing
Are you missing your winking emoticon?
If not, please stop with the Fireball XL5 / James Bond space prop descriptions.
Some of us are trying to be serious here.
Title: Re: Fairing reuse
Post by: AJW on 12/27/2015 06:04 AM
I'm pretty sure no one expects that Go Quest recovered a complete, intact, and reusable fairing from this mission.  But fairing fragments have washed up before, and Go Quest might have managed to locate some---or at least the piece which has the radio beacon and instrument package on it (if indeed some experiment of that sort was flown).
Go Quest would not be out looking for the fairing if they didn't intend to learn something from the pieces. The have found quite a few pieces already. What could have changed from the last mission to make them them want to go look for it?
 I'm not convinced GQ was looking for the fairing but if it was there must be something 'new' about this fairing.

One significant change is that GQ didn't have a specific role in an RTLS flight, so if the resource is available, retask it.   If you want to study fairing reuse, start by recovering a fairing from a flight and see what you can learn from it.  And yes, pieces of fairings have been recovered, but typically months, or even a year later when they have been subjected to other kinds of damage.
Title: Re: Fairing reuse
Post by: OxCartMark on 12/29/2015 04:05 AM
Have we touched on how fairings get transported from Hawthorne to the distant launch sites?  They are 5M in diameter and if shipped in two halves you are going to have a load that's either 5M high (too high for bridges even without a trailer underneath) or 5M wide (obnoxiously wide but maybe possible with permits and convoy) or some awkward diagonal compromise.  Are they really shipped in halves or perhaps they might be in quarter circle slivers that are joined at the launch site.  If this is as big of a transportation problem as I'm thinking that would be another contributor (besides cost) to the desire to achieve fairing reusability.

And its been mentioned that fairing fabrication takes up a lot of space in Hawthorne and that SpaceX is beginning to run out of factory floorspace in Hawthorne (its landlocked).  It seems to me that fairing fabrication (whether in a disposable or reusable scenario) is decoupled from other manufacturing processes in Hawthorne enough that it would be a good candidate for being moved to another or multiple other facilities (perhaps closer to launch sites).
Title: Re: Fairing reuse
Post by: oiorionsbelt on 12/29/2015 04:27 AM
Have we touched on how fairings get transported from Hawthorne to the distant launch sites?  They are 5M in diameter and if shipped in two halves you are going to have a load that's either 5M high (too high for bridges even without a trailer underneath) or 5M wide (obnoxiously wide but maybe possible with permits and convoy) or some awkward diagonal compromise. .
This was just posted somewhere here but here it is again.
Title: Re: Fairing reuse
Post by: QuantumG on 12/29/2015 05:26 AM
Ya know, it does basically look like a boat..
Title: Re: Fairing reuse
Post by: kch on 12/29/2015 05:55 AM
Ya know, it does basically look like a boat..

That it does.  I wonder if it might be able to generate lift (and perhaps be controllable), if properly oriented?
Title: Re: Fairing reuse
Post by: Zed_Noir on 12/29/2015 06:29 AM
Ya know, it does basically look like a boat..

That it does.  I wonder if it might be able to generate lift (and perhaps be controllable), if properly oriented?

If someone add some pop out cold gas attitude thrusters to a PLF segment for some test drops.
Title: Re: Fairing reuse
Post by: rds100 on 12/29/2015 07:16 AM

So is the fairing that expensive, to be worth the extra effort needed for reusing? I thought it's a fairly simple shell which can be machine fabricated, so shouldn't be very expensive.
Title: Re: Fairing reuse
Post by: Darkseraph on 12/29/2015 07:22 AM
I expect a propellant reuse thread any day soon... ;D


In all seriousness I don't think an off hand tweet is proof SpaceX are pouring very much effort into fairing reuse. They have already given up on second stage reuse for the Falcon 9 because it is more hassle than it is worth on this generation of vehicles. Fairings are bound to be a lot cheaper to construct than engines so making disposable fairings cheaper and/or lighter is probably a better use of time in the near term.

Some future vehicle with a reusable second stage could have a payload bay like the X37b/Shuttle. That won't be happening anytime soon though.  :/
Title: Re: Fairing reuse
Post by: QuantumG on 12/29/2015 09:35 AM
Last I heard they weren't even making them anymore. The kilns are not even at Hawthorn anymore are they?
Title: Re: Fairing reuse
Post by: MarekCyzio on 12/29/2015 11:45 AM
In all seriousness I don't think an off hand tweet is proof SpaceX are pouring very much effort into fairing reuse.

It is always a question of economics. Fairing may be relatively cheap, but also relatively easy to recover. It gets dropped at relatively low speeds, short exposures to saltwater do not cause significant damage, It only needs some simple systems to stabilize its descent (cold gas thrusters?, small aero fins or grids?), cushion water impact (drogue shute?) and keep it afloat for some time (baloons?). I am pretty sure SpaceX engineers are actively looking into this.
Title: Re: Fairing reuse
Post by: Johnnyhinbos on 12/29/2015 11:55 AM
I know fairings are relatively simple structures, but I would venture to say they are deceptively simple structures. They are, after all, the sharp end of the sward - they take the bulk of the air pressure (I believe) during launch and if think a failure in the fairing would really ruin someone's day. Large composites are difficult to manufacture as well as labor intensive and slow production rates. All that, to me, spells a compelling reason to strive for reuse.
Title: Re: Fairing reuse
Post by: sublimemarsupial on 12/29/2015 02:53 PM
Last I heard they weren't even making them anymore. The kilns are not even at Hawthorn anymore are they?

They are very much still making them, the tooling and ovens are quite a prominent sight on tours, and there's always a couple halves in work.
Title: Re: Fairing reuse
Post by: LouScheffer on 12/29/2015 04:12 PM

So is the fairing that expensive, to be worth the extra effort needed for reusing? I thought it's a fairly simple shell which can be machine fabricated, so shouldn't be very expensive.

ULA and Ariane buy fairings from RUAG, a European company.  Although the contracts are not super specific, they seem to indicate 5-6 million per fairing..  The post that discusses this is here:   http://forum.nasaspaceflight.com/index.php?topic=37727.msg1384676#msg1384676   This is not a huge fraction at current prices, but could become so if re-use works as hoped.
Title: Re: Fairing reuse
Post by: Robotbeat on 12/30/2015 12:04 AM
Way back in the day when Falcon 9 was supposed to have half the current performance, the cost of the big 5m fairing was a significant portion of the launch cost:

http://www.space.com/1533-spacex-tackle-fully-reusable-heavy-lift-launch-vehicle.html
Quote
In the medium configuration, Falcon 9 would be priced at $27 million per flight with a 12 ft (3.6 m) fairing and $35 million with a 17 ft fairing.

...a difference of $8 million(!), which is more than the projected per-launch costs of a fully reusable Falcon 9 back when a reusable 2nd stage for Falcon 9 was still seriously on the table. And keep in mind that's the DIFFERENCE in price between the smaller (aluminum, I think) fairing and the larger fairing.

Some of that no doubt is market segmentation and differences in handling difficulty, but it seems safe to say that a large composite fairing could correspond to several million dollars in fabrication costs.

So yeah, once SpaceX is launching like 40+ flights per year as SpaceX intends to do over the next 5+ years, you're talking hundreds of millions of dollars in fairings just thrown away. It may indeed make sense to start recovering them if it's not too difficult.
Title: Re: Fairing reuse
Post by: QuantumG on 12/30/2015 12:10 AM
They are very much still making them, the tooling and ovens are quite a prominent sight on tours, and there's always a couple halves in work.

Thanks. Is it still next to the coffee cart?
Title: Re: Fairing reuse
Post by: Comga on 12/30/2015 05:52 AM

So is the fairing that expensive, to be worth the extra effort needed for reusing? I thought it's a fairly simple shell which can be machine fabricated, so shouldn't be very expensive.

ULA and Ariane buy fairings from RUAG, a European company.  Although the contracts are not super specific, they seem to indicate 5-6 million per fairing..  The post that discusses this is here:   http://forum.nasaspaceflight.com/index.php?topic=37727.msg1384676#msg1384676 (http://forum.nasaspaceflight.com/index.php?topic=37727.msg1384676#msg1384676)   This is not a huge fraction at current prices, but could become so if re-use works as hoped.

Ms Shotwell once said (don't have the reference handy) $6-7M for an RTLS Falcon 9.
That surely does not include disposing of a $5-6M fairing, even if SpaceX makes it for half that cost
Title: Re: Fairing reuse
Post by: OxCartMark on 03/07/2016 03:34 AM
I'm hoping to move the recent discussion of the fairings to this dormant thread.  During the launch of SES-9 it there was a 2nd support ship, Go Searcher out which some speculated was for fairing recovery.  Then some commented that they saw puffs of thrust coming from the fairing halves.  I hope that its true but in the two great videos I've seen that show the fairing halves I'm not seeing it.  Thoughts / comments / observations?  Below are some posts I'm copying here for background.  There are other posts on this subject elsewhere as well.

So with the RCS visible from the fairings in launch video does it reinforce that GO Searcher is out supporting fairing recovery experiments?

That would be nice.  I've heard rumor of jets from the fairing halves in three places now but not seen it.  Can someone link the video?

edit: suggest we move any fairing discussion if it erupts into the fairing recovery thread that has been dormant for a while.  http://forum.nasaspaceflight.com/index.php?topic=37727.0

This video has a good view of the jets:  https://www.youtube.com/watch?v=3yuq8nUSdtY

edit: OK, we have the times to look for -
Puffs from the upper fairing half at 5:20 and 5:27.  Discuss, you know you want to.

edit2: Yes, I'm buying it, it appears that way.  Fairing seperated around 4:40 youtube time so at 5:20 the fairing had been off for 40 seconds and by the next puff 47 seconds.  By then the 2nd stage should have moved well ahead and we shouldn't be seeing exhaust impingement.
Title: Re: Fairing reuse
Post by: Robotbeat on 03/07/2016 04:10 AM
I could not see the puffs in question. Can you take a screenshot or series of stills to highlight what you believe is puffs from the fairing?? Even better would be a zoomed-in and stabilized GIF or video...
Title: Re: Fairing reuse
Post by: Ilikeboosterrockets on 03/07/2016 04:27 AM
At 5:00 you can see 4 bright objects on the frame. The top object (in the frame) is a fairing, the one below that is the second stage, the one below that is the other fairing half, and the object near the bottom is the first stage. At 5:03 you can see a puff from the first stage, which is a GN2 ACS thruster firing to reorient the stage for reentry.

At 5:20, you can kinda see a small puff from the top fairing directed downwards. At 5:27, just as the camera is focussing back you can see a big puff from the top fairing (which has by now fallen below the second stage) directed towards the left of the screen.
Title: Re: Fairing reuse
Post by: CJ on 03/07/2016 04:36 AM
I spotted one puff (there may have been others) from a fairing half. It looked just like the N2 puffs we see (and have seen before) from the first stage when it's maneuvering post-MECO, only weaker.

Seeing as how there aren't any known gas bottles on the fairings (?) IMHO, this is evidence of something new on the fairings, and probably to do with recovery.     

I can't get it to show well in a screengrab, and I can't edit video or make GIFs from one. If you watch the vid, make sure to set it to HD or you won't see it. The puff occurs at 5:27 and emanates from the upper fairing half, and moves right to left.

 
Title: Re: Fairing reuse
Post by: dorkmo on 03/07/2016 04:47 AM
I could not see the puffs in question. Can you take a screenshot or series of stills to highlight what you believe is puffs from the fairing?? Even better would be a zoomed-in and stabilized GIF or video...

around 5:20 youtube time, there appears to be one main puff then maybe a short one immediately following, then a third right as the camera pans down.

at 5:28 there is a single puff.

i think there might be two small puffs simultaniously at 5:08 on the upper fairing.
Title: Re: Fairing reuse
Post by: dorkmo on 03/07/2016 05:06 AM
ill mention that it seems like only one of the fairing halves is puffing. if this is indeed manuvering perhaps they are only testing one half to save weight.

personally i dont think there is enough evidence to say go searcher was for fairing recovery. though it could be possible.
Title: Re: Fairing reuse
Post by: OnWithTheShow on 03/07/2016 05:12 AM
Here is a gif
Title: Re: Fairing reuse
Post by: Jdeshetler on 03/07/2016 06:43 AM
Stabilized and close up...
Title: Re: Fairing reuse
Post by: thor1872 on 03/07/2016 06:54 AM
may be this can help

Fairing Jason-3
https://imgur.com/a/anZ4r
Source:
https://www.flickr.com/photos/nasakennedy/sets/72157651824508130

edit: I just saw that if you zoom in, you can see some black round, they hide something.
Title: Re: Fairing reuse
Post by: WBY1984 on 03/07/2016 07:22 AM
Can't quite understand what you're getting at: If you zoom in *where*, we see a black round *what*?
Title: Re: Fairing reuse
Post by: thor1872 on 03/07/2016 08:26 AM
Can't quite understand what you're getting at: If you zoom in *where*, we see a black round *what*?
https://imgur.com/lUPlvL9  ;)
Title: Re: Fairing reuse
Post by: ugordan on 03/07/2016 08:29 AM
Those would be separation joints/pushers. It's just your regular eyetar censorship.
Title: Re: Fairing reuse
Post by: woods170 on 03/07/2016 10:50 AM
Those would be separation joints/pushers. It's just your regular eyetar censorship.
No, not even that. Proprietary censorship. Blanking out the details in those images was done by SpaceX itself. They are the source for those images.
Title: Re: Fairing reuse
Post by: ugordan on 03/07/2016 10:52 AM
Those would be separation joints/pushers. It's just your regular eyetar censorship.
No, not even that. Proprietary censorship.

Perhaps, but eyetar sure comes in handy as an excuse.
Title: Re: Fairing reuse
Post by: WBY1984 on 03/07/2016 11:58 AM
So we've seen what might be RCS pulses coming from a fairing. My question is how does attitude control help recovery? I have no expertise, but why wouldn't you just stick a parachute on the thing and maybe a floatation device?
Title: Re: Fairing reuse
Post by: Robotbeat on 03/07/2016 12:19 PM
Stabilized and close up...
Wow, you all sure delivered!

There can be no question. Those look precisely like thruster firings.

They need thrusters to orient the fairings to come in at the correct orientation.

This is all fascinating. SpaceX continues to make surprising steps forward in reuse even when almost everyone else wouldn't bother. Bravo!
Title: Re: Fairing reuse
Post by: Chris Bergin on 03/07/2016 12:35 PM
I'm pulling this face:

(http://i.kinja-img.com/gawker-media/image/upload/s--D8CQa-Ot--/18gscgz2z6pnrjpg.jpg)

Didn't get any pre-note about this element (unlike the ballsy first stage landing attempt under three engines). I'm asking around, however!
Title: Re: Fairing reuse
Post by: WBY1984 on 03/07/2016 12:39 PM


They need thrusters to orient the fairings to come in at the correct orientation.



I guess what I'm asking is why do the fairings need to maintain a particular orienation at all? They aren't seperating much higher/faster than stage 1 MECO, and the fairings are both big and light, so I can't imagine they're all that thermally stressed on reentry. Why not let them tumble until parachute altitude?
Title: Re: Fairing reuse
Post by: R7 on 03/07/2016 12:45 PM
I guess what I'm asking is why do the fairings need to maintain a particular orienation at all? They aren't seperating much higher/faster than stage 1 MECO, and the fairings are both big and light, so I can't imagine they're all that thermally stressed on reentry. Why not let them tumble until parachute altitude?

Allowing something big, light and aerodynamically unstable to freely tumble in hypersonic wind is a good recipe for destructive mechanical stresses.
Title: Re: Fairing reuse
Post by: WBY1984 on 03/07/2016 12:48 PM
Thanks :)
Title: Re: Fairing reuse
Post by: OxCartMark on 03/07/2016 12:59 PM
what I'm asking is why do the fairings need to maintain a particular orienation at all?...Why not let them tumble until parachute altitude?

Buncha speculations:
- Because they've modeled the re-entry and found that one orientation is better than others
- Because they want to expose the outside surface which is not very heat tolerant epoxy to the heat rather than the inside surface which has expanded foam which is even less heat tolerant.
- Because they fly a predictable stable path if you get them concave down rather than tumbling and producing a less predictable landing point otherwise
- Because their longer range plan if they can get through re-entry is to add control surfaces to "fly" them through the lower atmosphere to a designated point for collection and you need to get them to a stable orientation to start that process

Separate observation: I find it interesting that the fairings are so far separated considering that their separation speed isn't that great and there is little aerodynamic influence.

What cameras or other resources do we have available in Port Canaveral to see if they were successful?
Title: Re: Fairing reuse
Post by: dorkmo on 03/07/2016 12:59 PM
Can't quite understand what you're getting at: If you zoom in *where*, we see a black round *what*?
https://imgur.com/lUPlvL9  ;)

not sure if its related but it looks like there is the top of a COPV with a pipe coming out right above the right shoulder of the guy on the right in blue jumpsuit.
Title: Re: Fairing reuse
Post by: Jim on 03/07/2016 01:29 PM
seeing as how there aren't any known gas bottles on the fairings

There are and this could be the system breaching from aero affects
Title: Re: Fairing reuse
Post by: WBY1984 on 03/07/2016 01:39 PM
seeing as how there aren't any known gas bottles on the fairings

There are and this could be the system breaching from aero affects

Yeah, seems just as likely as RCS to me. Should be skeptical until we know more.
Title: Re: Fairing reuse
Post by: ugordan on 03/07/2016 01:42 PM
seeing as how there aren't any known gas bottles on the fairings

There are and this could be the system breaching from aero affects

A mere 50 or so seconds after fairing sep? Unlikely. The thing was likely to still be way up above the atmosphere at that time.

Edit: trajectory analysis (https://plot.ly/~iannis/folder/iannis:96) by Reddit user ianniss shows fairing sep at a velocity of around 2.5 km/s, velocity angle around 13 deg above horizontal. The vertical displacement from faring sep altitude is then:

sin(13 deg)*2500m/s*50s - 10m/s /2*50s*50s = 28 km upward - 12.5 km downward. So the fairing halves were, in fact, still coasting up at that point.

The gas might have been autonomously vented, but aeroloads it wasn't.
Title: Re: Fairing reuse
Post by: thor1872 on 03/07/2016 01:44 PM
Can't quite understand what you're getting at: If you zoom in *where*, we see a black round *what*?
https://imgur.com/lUPlvL9  ;)

not sure if its related but it looks like there is the top of a COPV with a pipe coming out right above the right shoulder of the guy on the right in blue jumpsuit.
well seen
https://imgur.com/aRsIuDm
Title: Re: Fairing reuse
Post by: Jim on 03/07/2016 02:09 PM
seeing as how there aren't any known gas bottles on the fairings

There are and this could be the system breaching from aero affects

A mere 50 or so seconds after fairing sep? Unlikely. The thing was likely to still be way up above the atmosphere at that time.

Edit: trajectory analysis (https://plot.ly/~iannis/folder/iannis:96) by Reddit user ianniss shows fairing sep at a velocity of around 2.5 km/s, velocity angle around 13 deg above horizontal. The vertical displacement from faring sep altitude is then:

sin(13 deg)*2500m/s*50s - 10m/s /2*50s*50s = 28 km upward - 12.5 km downward. So the fairing halves were, in fact, still coasting up at that point.

The gas might have been autonomously vented, but aeroloads it wasn't.

Or the actual separation event.

https://www.youtube.com/watch?v=5r5me6mTQb4
Title: Re: Fairing reuse
Post by: obsever on 03/07/2016 02:16 PM
seeing as how there aren't any known gas bottles on the fairings

There are and this could be the system breaching from aero affects

A mere 50 or so seconds after fairing sep? Unlikely. The thing was likely to still be way up above the atmosphere at that time.

Edit: trajectory analysis (https://plot.ly/~iannis/folder/iannis:96) by Reddit user ianniss shows fairing sep at a velocity of around 2.5 km/s, velocity angle around 13 deg above horizontal. The vertical displacement from faring sep altitude is then:

sin(13 deg)*2500m/s*50s - 10m/s /2*50s*50s = 28 km upward - 12.5 km downward. So the fairing halves were, in fact, still coasting up at that point.

The gas might have been autonomously vented, but aeroloads it wasn't.

Or the actual separation event.

...

Wouldn't it be a lot less violent on F9 compared to Atlas, since they are using a non-pyrotechnic method (pushers) on F9 ?

Edit: in the video from the test the separation event looks more smooth than the Atlas one you linked above:

https://www.youtube.com/watch?v=LtI1V624vWM
Title: Re: Fairing reuse
Post by: Flying Beaver on 03/07/2016 02:46 PM
The Helium bottles used for pneumatic fairing sep are pictured here (from Nov 2012):

https://www.flickr.com/photos/jurvetson/8233306859/
Title: Re: Fairing reuse
Post by: Ilikeboosterrockets on 03/07/2016 02:53 PM
I'm wondering if it was those helium bottles leaking instead of thrusters. Is there any difference in the visibility of helium outgassing vs. something like nitrogen?
Title: Re: Fairing reuse
Post by: Flying Beaver on 03/07/2016 03:05 PM
I'm wondering if it was those helium bottles leaking instead of thrusters. Is there any difference in the visibility of helium outgassing vs. something like nitrogen?

I might be mistaken, but in a vacuum Nitrogen freezes and produces ice crystals (hence the name "Cold Gas Thrusters" on the first stage). Where as helium simply disperses invisibly.
Title: Re: Fairing reuse
Post by: Robotbeat on 03/07/2016 03:17 PM
I'm wondering if it was those helium bottles leaking instead of thrusters. Is there any difference in the visibility of helium outgassing vs. something like nitrogen?
Although helium does not condense, I wouldn't expect a visible sign from helium venting, but... That is the best alternative explanation I've heard so far.

But it might not even be contradictory. They may be venting what's left in the bottles out through a nozzle to test some aspect of fairing recovery hardware.

Do we know for a fact the pushers use helium and not nitrogen?
Title: Re: Fairing reuse
Post by: Jim on 03/07/2016 03:25 PM

I might be mistaken, but in a vacuum Nitrogen freezes and produces ice crystals (hence the name "Cold Gas Thrusters" on the first stage). Where as helium simply disperses invisibly.

No, nitrogen does not freeze nor does it contain any water.  Any gas venting in a vacuum would be visible
Title: Re: Fairing reuse
Post by: Saabstory88 on 03/07/2016 03:45 PM
Maybe this is a stupid question, but wouldn't the fairing half passing through the second stage plume also create an effect like this?
Title: Re: Fairing reuse
Post by: ugordan on 03/07/2016 03:48 PM
Maybe this is a stupid question, but wouldn't the fairing half passing through the second stage plume also create an effect like this?

There would be around 10 km distance between the fairing and engine around 50 seconds after fairing sep. Highly unlikely.
Title: Re: Fairing reuse
Post by: AS-503 on 03/07/2016 03:51 PM

I might be mistaken, but in a vacuum Nitrogen freezes and produces ice crystals (hence the name "Cold Gas Thrusters" on the first stage). Where as helium simply disperses invisibly.

No, nitrogen does not freeze nor does it contain any water.  Any gas venting in a vacuum would be visible

Then I am puzzled why most upper stage exhaust plumes are not visible?
Title: Re: Fairing reuse
Post by: Saabstory88 on 03/07/2016 03:57 PM
Maybe this is a stupid question, but wouldn't the fairing half passing through the second stage plume also create an effect like this?

There would be around 10 km distance between the fairing and engine around 50 seconds after fairing sep. Highly unlikely.

I mention this because we only see the "thrusts" from the fairing half which appears to be trailing in the second stage exhaust plumes. I mean, of course, this is SpaceX we are talking about, but I'm just trying to remain skeptical. What's more likely, that only one of the fairings needs to complete maneuvers, or that the fairing caught in the plume redirects some gas as it spins in free fall?
Title: Re: Fairing reuse
Post by: Hauerg on 03/07/2016 03:58 PM
They only test with one half. The other is a point of reference.
Title: Re: Fairing reuse
Post by: pippin on 03/07/2016 04:08 PM
If this is really a reuse experiment, are they trying to land the fairing without a parachute? I mean... Given the shape and lightness it _should_ be possible to use that thing as a wing if they find a way to get enough control authority
Title: Re: Fairing reuse
Post by: Kabloona on 03/07/2016 04:10 PM
They only test with one half. The other is a point of reference.

Yes, logical explanation for why gas jet is visible from only one fairing half.
Title: Re: Fairing reuse
Post by: ugordan on 03/07/2016 04:16 PM
Another thing is that only one half of the fairing contains the gas bottles for the sep pushers. Easier to outfit that one with ACS than introduce gas bottles to the other half as well.
Title: Re: Fairing reuse
Post by: Jim on 03/07/2016 04:26 PM
Another thing is that only one half of the fairing contains the gas bottles for the sep pushers. Easier to outfit that one with ACS than introduce gas bottles to the other half as well.

Or it is the only half that can leak gas, since the other doesn't have bottles.
Title: Re: Fairing reuse
Post by: ugordan on 03/07/2016 04:44 PM
Another thing is that only one half of the fairing contains the gas bottles for the sep pushers. Easier to outfit that one with ACS than introduce gas bottles to the other half as well.

Or it is the only half that can leak gas, since the other doesn't have bottles.

http://forum.nasaspaceflight.com/index.php?topic=34077.msg1500497#msg1500497

Title: Re: Fairing reuse
Post by: dorkmo on 03/07/2016 07:09 PM

I might be mistaken, but in a vacuum Nitrogen freezes and produces ice crystals (hence the name "Cold Gas Thrusters" on the first stage). Where as helium simply disperses invisibly.

No, nitrogen does not freeze nor does it contain any water.  Any gas venting in a vacuum would be visible

Then I am puzzled why most upper stage exhaust plumes are not visible?

im not an expert but i believe it has to do with the short amount of time it takes for the gas to dissipate in the vacuum.
Title: Re: Fairing reuse
Post by: Nomadd on 03/07/2016 07:14 PM
 I don't believe that venting gas is visible. The liquid or ice that it turns into is visible.
Title: Re: Fairing reuse
Post by: matthewkantar on 03/07/2016 08:16 PM
The exhaust plume from the second stage seems huge, maybe what is observed is the vented gas displacing the plume, not the gas itself.

Matthew
Title: Re: Fairing reuse
Post by: llanitedave on 03/07/2016 10:05 PM
I guess what I'm asking is why do the fairings need to maintain a particular orienation at all? They aren't seperating much higher/faster than stage 1 MECO, and the fairings are both big and light, so I can't imagine they're all that thermally stressed on reentry. Why not let them tumble until parachute altitude?

Allowing something big, light and aerodynamically unstable to freely tumble in hypersonic wind is a good recipe for destructive mechanical stresses.


Is it possible that what we're seeing is fragmentation of some of the fairing internals, for instance, the softer insulation materials, under re-entry stresses?  Or is it too early in the sequence for that?


Edit: After reading the posts following the one I quoted I agree this is unlikely.
Title: Re: Fairing reuse
Post by: Kabloona on 03/07/2016 10:22 PM
Support ships GO Quest and GO Searcher have returned to port, with no fairing pieces visible on deck. So I lost my dollar bet...
Title: Re: Fairing reuse
Post by: Jim on 03/08/2016 01:20 AM
I don't believe that venting gas is visible. The liquid or ice that it turns into is visible.

http://history.nasa.gov/SP-4206/ch12.htm
Title: Re: Fairing reuse
Post by: dorkmo on 03/08/2016 01:37 AM
just some "duh" thoughts...

since the latch mechanism has a pretty heavy duty gas supply, it seems like there would always be some gas left over as margin. adding thrusters could mean tapping into an existing infrastructure. for not much added weight they can play around till the gas is depleted.
Title: Re: Fairing reuse
Post by: Jim on 03/08/2016 01:44 AM
just some "duh" thoughts...

since the latch mechanism has a pretty heavy duty gas supply,

it may be high pressure but it would be a small amount of gas
Title: Re: Fairing reuse
Post by: intrepidpursuit on 03/08/2016 04:37 AM
If they are doing reentry control testing with the fairings, I highly doubt they would touch the existing fairing separation system. If something goes wrong with that the mission fails. They would put in a separate system for the reuse functions and not mess with the fairing sep that has worked perfectly every time. I also don't see why they would vent helium in this case. Once the fairing separates it is gone, why do they care if there is a half full helium tank on it?

The video looks very, very much like the nitrogen thrusters firing around the same time from the first stage. I doubt they would do this on just one fairing half though, they have plenty of data on the fairings falling. Seems odd too that they would separate in such an orientation that one fairing half is above the other, as opposed to jettisoning them side to side. Then one has to fall back through the plume and the other doesn't. Perhaps the plume is hitting the stage and causing it to tumble, so we see irregular plume interference based on the orientation of the fairing.

I hope it is fairing reuse, and the evidence is somewhat compelling. But I'm not yet convinced.
Title: Re: Fairing reuse
Post by: rst on 03/08/2016 08:30 PM
If they are doing reentry control testing with the fairings, I highly doubt they would touch the existing fairing separation system. If something goes wrong with that the mission fails.

That depends, to some extent, on what modifications we're talking about.  If it involves changing the number or positioning of thrusters, that's risky.  If, on the other hand, it involves just giving the pre-existing thrusters bigger propellant tanks, perhaps less so...
Title: Re: Fairing reuse
Post by: Chris_Pi on 03/08/2016 09:11 PM
That depends, to some extent, on what modifications we're talking about.  If it involves changing the number or positioning of thrusters, that's risky.  If, on the other hand, it involves just giving the pre-existing thrusters bigger propellant tanks, perhaps less so...

Separation is done with pushers - A few pages back there's video of a separation test where they can be seen. Any attitude control stuff would be additional to that. Could be entirely separate, Could be tied in to the gas supply and using whatever leftovers there after separation. That would allow limited tests with very little weight added.
Title: Re: Fairing reuse
Post by: OxCartMark on 03/09/2016 03:50 PM
Separation is done with pushers

I've always known it was done with pushers and I think N gas pushers but I'm surprised by the technology path they've chosen. I always assumed that they used COTS nitrogen gas springs of the type used in automotive lift gates or the type used in stamping dies.  In my scenario the halves would be held together with electrically releasable latches such as on car trunks.  I guess those assumptions show the field that I've been working in.  But also now see that if they'd have chosen the path that I envision there'd be challenges in bringing the fairing halves together evenly against the multiple springs.
Title: Re: Fairing reuse
Post by: sghill on 03/10/2016 03:47 PM
Why not develop a fairing that peels back like a banana peel and locks against the second stage skin? Kind of like the legs, but in reverse.

It could be used as a TPS for the second stage so the stage can be recovered.
Title: Re: Fairing reuse
Post by: Jim on 03/10/2016 03:53 PM
Why not develop a fairing that peels back like a banana peel and locks against the second stage skin? Kind of like the legs, but in reverse.

It could be used as a TPS for the second stage so the stage can be recovered.

No need to peel it back if it is taken to orbit.  It could be opened right before spacecraft deployment.  But the fairing would reduce payload mass.
Title: Re: Fairing reuse
Post by: CyndyC on 03/10/2016 04:28 PM
Why not develop a fairing that peels back like a banana peel and locks against the second stage skin? Kind of like the legs, but in reverse.

It could be used as a TPS for the second stage so the stage can be recovered.

No need to peel it back if it is taken to orbit.  It could be opened right before spacecraft deployment.  But the fairing would reduce payload mass.

Bouncing off these 2 posts and after reading most everything in the L2 thread on the subject, why not just close the thing back up, and recover stage 2 and the fairing together. During the time the fairing is hanging open for payload separation, the aerodynamics would be related to opening a convertible top while driving, which I was told to never do because it would act like a sail and flip the car, but in space, there you have your boostback maneuver.

Edit: Maybe forget the last part since I just remembered there's little to no air that high, but maybe the shifts in mass could be used to assist in boostback.
Title: Re: Fairing reuse
Post by: Robotbeat on 03/10/2016 05:39 PM
 Atlas has its 5 m faring attached to the first stage. Something like that might make sense for a reasonable fairing since you don't have to take the whole thing to orbit. It would also protect the thermal protection system on the upper stage from water ingress  and condensation while it's sitting on the pad .
Title: Re: Fairing reuse
Post by: OxCartMark on 03/10/2016 05:59 PM
Rough numbers but you get the idea;

What's F9's payload capacity to GTO?  10,000 pounds?
What's the weight of the payload fairing?  5,000 pounds?
What's the revised payload capacity if you take the payload fairing along for the whole ride?  ?5000? pounds.

Substitute in actual numbers and you get actually poor numbers.  Weight carried on the first stage is not good.  Weight carried on the second stage is really not good.
Title: Re: Fairing reuse
Post by: mfck on 03/10/2016 06:25 PM
Atlas has its 5 m faring attached to the first stage. Something like that might make sense for a reasonable fairing since you don't have to take the whole thing to orbit. It would also protect the thermal protection system on the upper stage from water ingress  and condensation while it's sitting on the pad .
Am I right to remember that AV booster separates much higher and at a higher speed?
Title: Re: Fairing reuse
Post by: RanulfC on 03/10/2016 08:58 PM
Rough numbers but you get the idea;

What's F9's payload capacity to GTO?  10,000 pounds?
What's the weight of the payload fairing?  5,000 pounds?
What's the revised payload capacity if you take the payload fairing along for the whole ride?  ?5000? pounds.

Substitute in actual numbers and you get actually poor numbers.  Weight carried on the first stage is not good.  Weight carried on the second stage is really not good.

Not actual numbers but IIRC the quoted formula was something like order of the 30% penalty for first stage reusability to payload was closer to one-to-one for the second stage, which would include keeping the fairing. The fairing is jettisoned when it is specifically because the mass is enough to impact the payload mass to orbit.

It's been touched on but not addressed specifically as far as I've seen but adding ANY mass to the fairing would also change the separation dynamics. Enough so you'd have to test the whole system again to ensure clean separation from the payload which is your MAIN (and that includes anything about reusability) metric. If they added piping and a thruster, (and really it would be at least four nozzles for proper control) and control and regulator equipment you've off-balanced the system and voided any previous testing results.

Randy
Title: Re: Fairing reuse
Post by: Chris Bergin on 03/10/2016 09:04 PM
I'll add my "update" on this after asking around. SpaceX has not commented on it, but a few sources (not SpaceXers it's worth adding) note it was an ACS experiment as part of fairing recovery evaluations.

For it to become official, SpaceX needs to say something and that would likely be either Elon tweeting or Gywnne mentioning it at a conference....but there you go from my chair.

For the interim this can be a fun thread where you talented folks can work the imagery, as we saw with this cool gifs:
http://forum.nasaspaceflight.com/index.php?topic=37727.msg1500634#msg1500634
Title: Re: Fairing reuse
Post by: symbios on 03/11/2016 07:23 PM
New image on Facebook.

Anyone recognises the logo in the fairing in the background back right.
Title: Re: Fairing reuse
Post by: ugordan on 03/11/2016 07:35 PM
Eutelsat?

FH booster nosecone as well.
Title: Re: Fairing reuse
Post by: Retired Downrange on 03/11/2016 08:08 PM
Any guesses about what the white curved structure barely visible in the extreme lower right of the photo might be? If it is not part of the building, it certainly is of a much larger diameter that anything else in the photo.
Title: Re: Fairing reuse
Post by: Kabloona on 03/11/2016 09:40 PM
Eutelsat?

Probably for Eutelsat's Satmex 9, which is up next after CRS-8.
Title: Re: Fairing reuse
Post by: pippin on 03/11/2016 09:55 PM

Any guesses about what the white curved structure barely visible in the extreme lower right of the photo might be? If it is not part of the building, it certainly is of a much larger diameter that anything else in the photo.
Oven to bake composite structures?
Title: Re: Fairing reuse
Post by: OxCartMark on 03/11/2016 10:46 PM
Nice pic.  Thanks.  I'm not convinced that the round thing is significantly larger in diameter but maybe it is larger in which case an autoclave makes sense.  Perhaps they chose the interesting route of making their own cylindrical housing with friction stir welding.  Say, what's that robot arm process going on under the unpainted fairing half in the foreground?
Title: Re: Fairing reuse
Post by: Robotbeat on 03/12/2016 12:39 AM
Autoclaves definitely don't look like that.
Title: Re: Fairing reuse
Post by: Lee Jay on 03/12/2016 12:45 AM
Autoclaves definitely don't look like that.

Yeah...they look a lot like a submarine with one end that opens.
Title: Re: Fairing reuse
Post by: Robotbeat on 03/12/2016 12:47 AM
And they're made out of thick steel. That thing looks like it's made out of aerospace materials like aluminum or carbon fiber.
Title: Re: Fairing reuse
Post by: Lee Jay on 03/12/2016 12:53 AM
Yeah...like a submarine!

(https://upload.wikimedia.org/wikipedia/en/4/47/Industrial_Autoclaves.jpg)
Title: Re: Fairing reuse
Post by: Lee Jay on 03/12/2016 12:59 AM
Do they autoclave their fairings?  That would be a huge autoclave.
Title: Re: Fairing reuse
Post by: virnin on 03/12/2016 01:08 AM
Any guesses about what the white curved structure barely visible in the extreme lower right of the photo might be? If it is not part of the building, it certainly is of a much larger diameter that anything else in the photo.

It's too blurry to be sure but it looks like there is a removable port near the base like you would see in a boiler or a storage tank that had to be periodically cleaned.
Title: Re: Fairing reuse
Post by: Burninate on 03/12/2016 01:46 AM
Wild-ass guesses corroborated by nothing whatsoever:

The observed thrust is venting of the remaining pressure in an N2 pneumatic tank normally used in separation, associated with some safety procedure they're testing for Falcon Heavy, which will drop fairings (or perhaps interstage?) on a trajectory much closer to the launchsite in order to optimize RTLS.  They want the chance of ballistically dropping pressurized cylinders near population to be closer to zero than it is at present.

The cylinder is either a finished fairing at an angle, or a fairing spray/cure booth.  As mentioned upthread, fairings are delivered from overseas rather than manufactured in-house, but the center of the picture indicates they may not be painted when they get here.  Alternately, it's possible that it's an interstage or a stage that's simply suffering from some flavor of perspective distortion.
Title: Re: Fairing reuse
Post by: Robotbeat on 03/12/2016 01:57 AM
Wild-ass guesses corroborated by nothing whatsoever:

The observed thrust is venting of the remaining pressure in an N2 pneumatic tank normally used in separation, associated with some safety procedure they're testing for Falcon Heavy, which will drop fairings (or perhaps interstage?) on a trajectory much closer to the launchsite in order to optimize RTLS.  They want the chance of ballistically dropping pressurized cylinders near population to be closer to zero than it is at present.

The cylinder is either a finished fairing at an angle, or a fairing spray/cure booth.  As mentioned upthread, fairings are delivered from overseas rather than manufactured in-house, but the center of the picture indicates they may not be painted when they get here.  Alternately, it's possible that it's an interstage or a stage that's simply suffering from some flavor of perspective distortion.
They make fairings in-house. Do you have a source for your statement that they aren't?
Title: Re: Fairing reuse
Post by: Burninate on 03/12/2016 02:03 AM
Wild-ass guesses corroborated by nothing whatsoever:

The observed thrust is venting of the remaining pressure in an N2 pneumatic tank normally used in separation, associated with some safety procedure they're testing for Falcon Heavy, which will drop fairings (or perhaps interstage?) on a trajectory much closer to the launchsite in order to optimize RTLS.  They want the chance of ballistically dropping pressurized cylinders near population to be closer to zero than it is at present.

The cylinder is either a finished fairing at an angle, or a fairing spray/cure booth.  As mentioned upthread, fairings are delivered from overseas rather than manufactured in-house, but the center of the picture indicates they may not be painted when they get here.  Alternately, it's possible that it's an interstage or a stage that's simply suffering from some flavor of perspective distortion.
They make fairings in-house. Do you have a source for your statement that they aren't?

My mistake, I misread something a few pages back.
Title: Re: Fairing reuse
Post by: sewebster on 03/12/2016 04:28 AM
Do they autoclave their fairings?  That would be a huge autoclave.

I assume they do? Aerospace autoclaves are rather large... Dreamliner autoclave is 9 m dia, 30 m long.
Title: Re: Fairing reuse
Post by: kkellogg on 03/13/2016 11:48 PM
Any guesses about what the white curved structure barely visible in the extreme lower right of the photo might be? If it is not part of the building, it certainly is of a much larger diameter that anything else in the photo.

I think it's a tank section for either F9 or FH.
Title: Re: Fairing reuse
Post by: CraigLieb on 03/14/2016 02:49 AM
Any guesses about what the white curved structure barely visible in the extreme lower right of the photo might be? If it is not part of the building, it certainly is of a much larger diameter that anything else in the photo.

I think it's a tank section for either F9 or FH.

I looked through as many of the building tour videos and pictures as I could find and didn't
See that in any of them.
Title: Re: Fairing reuse
Post by: dorkmo on 03/14/2016 03:01 AM
Any guesses about what the white curved structure barely visible in the extreme lower right of the photo might be? If it is not part of the building, it certainly is of a much larger diameter that anything else in the photo.

I think it's a tank section for either F9 or FH.

I looked through as many of the building tour videos and pictures as I could find and didn't
See that in any of them.

to me it looks like an interstage that has wiring on its exterior. what can be seen at the base looks like the holes for gridfins. not completely painted there. exterior wiring is a bit perplexing but makes me think its for a test flight which might mean heavy demo?
Title: Re: Fairing reuse
Post by: iamlucky13 on 03/14/2016 07:31 PM
Separation is done with pushers

I've always known it was done with pushers and I think N gas pushers but I'm surprised by the technology path they've chosen. I always assumed that they used COTS nitrogen gas springs of the type used in automotive lift gates or the type used in stamping dies.  In my scenario the halves would be held together with electrically releasable latches such as on car trunks.  I guess those assumptions show the field that I've been working in.  But also now see that if they'd have chosen the path that I envision there'd be challenges in bringing the fairing halves together evenly against the multiple springs.

Using a depressurized actuator, separate pressure reservoir, and a control valve can allow you to withdraw the latch pin without the push loads already on the fairing trying to bind up the latches.

The assembly problem of your idea can be avoided, however, by designing room for a retainer to hold the spring compressed in the right position until the latches are closed. Forgetting to do this with high force springs is huge pain the rear. Been there, done that, fortunately did not lose any fingers.
Title: Re: Fairing reuse
Post by: CyndyC on 03/15/2016 01:09 AM
(http://public.cyndyclayton.fastmail.us/Flight/Rocket%20Fairing%20Closed%20139w.png)          (http://public.cyndyclayton.fastmail.us/Flight/Rocket%20Fairing%20Open%20200w.png)
Title: Re: Fairing reuse
Post by: meekGee on 03/15/2016 01:56 AM
(http://public.cyndyclayton.fastmail.us/Flight/Rocket%20Fairing%20Closed%20200w.png)          (http://public.cyndyclayton.fastmail.us/Flight/Rocket%20Fairing%20Open%20200w.png)

An odd patent... (Low shock separation joint - US 7127994 B2)

Most of the spec is about a separation joint - nothing to do with a retained split fairing design...

Then there are these two figures at the end, seemingly out of the blue, a bit of text, and no claims related to this mechanism.

Sometimes you add text to prove the utility of the patent, but this doesn't look like it at all...

head scratch...

(And I doubt anyone can patent the idea of a retained split fairing anyway...  )
Title: Re: Fairing reuse
Post by: CyndyC on 03/15/2016 02:11 AM
An odd patent... (Low shock separation joint - US 7127994 B2)

Most of the spec is about a separation joint - nothing to do with a retained split fairing design...

Then there are these two figures at the end, seemingly out of the blue, a bit of text, and no claims related to this mechanism.

Sometimes you add text to prove the utility of the patent, but this doesn't look like it at all...

head scratch...

(And I doubt anyone can patent the idea of a retained split fairing anyway...  )

Wow, how were you able to find the name and number? I came across it for a Biomimicry class assignment, and it seemed to fit the discussion here in a few & funny ways. Your doubts are not surprising since the patent has lapsed.
Title: Re: Fairing reuse
Post by: meekGee on 03/15/2016 03:13 AM
An odd patent... (Low shock separation joint - US 7127994 B2)

Most of the spec is about a separation joint - nothing to do with a retained split fairing design...

Then there are these two figures at the end, seemingly out of the blue, a bit of text, and no claims related to this mechanism.

Sometimes you add text to prove the utility of the patent, but this doesn't look like it at all...

head scratch...

(And I doubt anyone can patent the idea of a retained split fairing anyway...  )

Wow, how were you able to find the name and number? I came across it for a Biomimicry class assignment, and it seemed to fit the discussion here in a few & funny ways. Your doubts are not surprising since the patent has lapsed.

Google Image Search, click the camera, then can search by URL...  If using chrome, there's a direct right-click short cut.

The amount of riddles this has solved for me...
Title: Re: Fairing reuse
Post by: wannamoonbase on 03/18/2016 02:47 PM
Anyone hazard a guess on how well retrieval would work during night launches?
Title: Re: Fairing reuse
Post by: Jarnis on 03/18/2016 03:50 PM
Anyone hazard a guess on how well retrieval would work during night launches?

Night vision goggles are fairly mature tech, as is flying in darkness with them.
Title: Re: Fairing reuse
Post by: Rabidpanda on 03/19/2016 08:59 AM

Do they autoclave their fairings?  That would be a huge autoclave.

I assume they do? Aerospace autoclaves are rather large... Dreamliner autoclave is 9 m dia, 30 m long.

The fairings are cured in an oven, not an autoclave.
Title: Re: Fairing reuse
Post by: sewebster on 03/20/2016 05:33 PM

Do they autoclave their fairings?  That would be a huge autoclave.

I assume they do? Aerospace autoclaves are rather large... Dreamliner autoclave is 9 m dia, 30 m long.

The fairings are cured in an oven, not an autoclave.

Thanks. Do you know how they apply pressure to the parts?
Title: Re: Fairing reuse
Post by: Robotbeat on 03/20/2016 06:11 PM

Do they autoclave their fairings?  That would be a huge autoclave.

I assume they do? Aerospace autoclaves are rather large... Dreamliner autoclave is 9 m dia, 30 m long.

The fairings are cured in an oven, not an autoclave.

Thanks. Do you know how they apply pressure to the parts?
Perhaps they vacuum bag them?
Title: Re: Fairing reuse
Post by: sewebster on 03/20/2016 08:39 PM
The fairings are cured in an oven, not an autoclave.

Thanks. Do you know how they apply pressure to the parts?
Perhaps they vacuum bag them?

Yes, seems likely, but autoclaves are used in addition to vacuum to apply more pressure to reduce voids etc. Vacuum can only give you one atmosphere. There are other techniques for applying more pressure that don't involve an autoclave... https://en.wikipedia.org/wiki/Out_of_autoclave_composite_manufacturing
Title: Re: Fairing reuse
Post by: Rabidpanda on 03/21/2016 03:45 AM


Do they autoclave their fairings?  That would be a huge autoclave.

I assume they do? Aerospace autoclaves are rather large... Dreamliner autoclave is 9 m dia, 30 m long.

The fairings are cured in an oven, not an autoclave.

Thanks. Do you know how they apply pressure to the parts?
Perhaps they vacuum bag them?

Yes, they are vacuum bagged.
Title: Re: Fairing reuse
Post by: Stan-1967 on 03/21/2016 04:04 AM
Rough numbers but you get the idea;

What's F9's payload capacity to GTO?  10,000 pounds?
What's the weight of the payload fairing?  5,000 pounds?
What's the revised payload capacity if you take the payload fairing along for the whole ride?  ?5000? pounds.

Substitute in actual numbers and you get actually poor numbers.  Weight carried on the first stage is not good.  Weight carried on the second stage is really not good.

Very poor numbers indeed.  Recall the Taurus XL vehicle that failed to jettison the fairing on the launch of the "Orbiting Carbon Observatory", and "Glory".  In both cases the vehicle failed to reach orbit.   
Title: Re: Fairing reuse
Post by: Stan-1967 on 03/21/2016 04:47 AM
(http://public.cyndyclayton.fastmail.us/Flight/Rocket%20Fairing%20Closed%20139w.png)          (http://public.cyndyclayton.fastmail.us/Flight/Rocket%20Fairing%20Open%20200w.png)

Why not develop a fairing that peels back like a banana peel and locks against the second stage skin? Kind of like the legs, but in reverse.

It could be used as a TPS for the second stage so the stage can be recovered.

No need to peel it back if it is taken to orbit.  It could be opened right before spacecraft deployment.  But the fairing would reduce payload mass.

1.  Is there substantial advantage to recovering a fairing like in the schematic above as a single assembly, vs. trying to recover two individual halves?   The aerodynamics of the fairing re-joined together seem more suited to surviving & conducting a controlled reentry. 

2.  The fact that F9 fairings have been recovered, either in pieces or near complete halves, show that they are strong enough to withstand reentry.  However I don't see that the "halves" are going to be controllable during descent, which makes the condition they survive in questionable.

3.   If the springs in the schematic were mounted on the outside of that "interstage" looking attachment hoop instead of the inside, they could still be used to open up the hinged fairing.   (encasing the springs in an aeroshell/fairing of sorts)   If the mounting hoop that the fairing halves are hinged to has a larger inner diameter than the outer diameter of the second/final stage, you could slide the entire opened up fairing & mounting hoop down the side of the stage and jettison it at the rear of the rocket, into the plume of the accelerating stage.  It would have to have clearance of the payload pedestal & payloads, as well as any exterior plumbing on the side of the rocket.

4.  After the fairing halves & mounting hoop has slid down the length of the accelerating rocket, & is clear of the engine nozzles & associated gas plume,  you could close and lock the halves and have a very aerodynamic shape for controlled reentry and recovery.
Title: Re: Fairing reuse
Post by: Jim on 03/21/2016 02:52 PM


2.  The fact that F9 fairings have been recovered, either in pieces or near complete halves, show that they are strong enough to withstand reentry.

It was pieces, which is standard for all fairings and not just F9.  Most just sink.  It has nothing to with strength or withstanding.
Title: Re: Fairing reuse
Post by: cambrianera on 03/21/2016 07:09 PM

If the mounting hoop that the fairing halves are hinged to has a larger inner diameter than the outer diameter of the second/final stage, you could slide the entire opened up fairing & mounting hoop down the side of the stage and jettison it at the rear of the rocket, into the plume of the accelerating stage.  It would have to have clearance of the payload pedestal & payloads, as well as any exterior plumbing on the side of the rocket.


You don't need a full clamshell opening to slide your fairing back.
And making the cylindrical part of the fairing in a single piece, without joints, you can save a good amount of mass.
"Small" problem: sliding the fairing into the plume of the accelerating stage you are likely going to shred it in pieces smaller than those previously recovered.
I did this animation to look at the concept some month ago, then I realized the "small" problem .
Title: Re: Fairing reuse
Post by: Stan-1967 on 03/21/2016 11:19 PM

If the mounting hoop that the fairing halves are hinged to has a larger inner diameter than the outer diameter of the second/final stage, you could slide the entire opened up fairing & mounting hoop down the side of the stage and jettison it at the rear of the rocket, into the plume of the accelerating stage.  It would have to have clearance of the payload pedestal & payloads, as well as any exterior plumbing on the side of the rocket.


You don't need a full clamshell opening to slide your fairing back.
And making the cylindrical part of the fairing in a single piece, without joints, you can save a good amount of mass.
"Small" problem: sliding the fairing into the plume of the accelerating stage you are likely going to shred it in pieces smaller than those previously recovered.
I did this animation to look at the concept some month ago, then I realized the "small" problem .

Nice animation!  Captures the concept exactly.  I wonder if the "small" problem of the exhaust plume could be avoided if the rocket flew a more highly lofted trajectory and jettison the fairing right after MECO and before second stage ignition, using smaller ullage rockets?  Alternately throttle down the S2 engine as far as possible during jettison.   My first thoughts was that the potential to tear apart the fairing would look like the Saturn V second stage interstage in this clip.  ( it survived a bit scorched apparently )

https://www.youtube.com/watch?v=HTGk3UM-IOU#t=4m23s

Title: Re: Fairing reuse
Post by: Chris_Pi on 03/22/2016 02:00 AM
That Saturn interstage started to tumble pretty quick. I think having the engine running at all when the longer Falcon fairing drops down the whole length of the second stage might be a problem. Jettisoning or folding out the rear bevel on the fairing would increase the clearance quite a bit but it still has to come off very straight and preferably fast so the second stage can get started.

More than a few degrees rotation during separation and the fairing starts bumping into important parts. It could probably work but fairing separation would definitely not be boring for a while. :-\ More like a second really long interstage.
Title: Re: Fairing reuse
Post by: dorkmo on 03/22/2016 02:31 AM
im not really following, but for an idea, perhaps following seperation using thrusters the two halves could quickly dock with one another to become one again.
Title: Re: Fairing reuse
Post by: hrissan on 03/22/2016 10:12 AM
Might the future fairing be attached to the first stage and return together with it?
Title: Re: Fairing reuse
Post by: rpapo on 03/22/2016 10:51 AM
Might the future fairing be attached to the first stage and return together with it?
To do that, it would probably have to (1) cover the entire second stage, (2) be able to open very quickly at staging time and (3) survive the starting of the second stage motors.

If it could do all that, and close on its own, then it would probably help the aerodynamics of stage return by pushing the center of drag even higher on the stage.  That said, that would reduce the effectiveness of the grid fins unless they were moved even higher than they already are.
Title: Re: Fairing reuse
Post by: cambrianera on 03/22/2016 10:59 AM
@Stan:
Sliding the fairing before MECO you can lock it on the upper part of the interstage, and get a free ride back to earth (what hrissan wrote): I remember Jim said spacecrafts need protection also after MECO, therefore this should be carefully balanced.
Throttling down second stage engine to minimum during sliding may be ok (but not a given).
@Chris:
A sliding fairing should have rails, therefore a straighter path & no lateral jerks on separation.
@dorkmo:
This means add to them complete navigation & RCS....
Title: Re: Fairing reuse
Post by: Stan-1967 on 03/23/2016 02:53 PM
@Stan:
Sliding the fairing before MECO you can lock it on the upper part of the interstage, and get a free ride back to earth (what hrissan wrote): I remember Jim said spacecrafts need protection also after MECO, therefore this should be carefully balanced.
Throttling down second stage engine to minimum during sliding may be ok (but not a given).
@Chris:
A sliding fairing should have rails, therefore a straighter path & no lateral jerks on separation.
@dorkmo:
This means add to them complete navigation & RCS....

I like the idea of sliding the fairing all the way onto S1 for the return ride, but I think this concept would then be limited to rockets with a S1 that delivers S2 & payload at very high altitudes where the exposed payload would not be damaged.  In reading the SpaceX F9 users manual, fairing jettison is predicated on the dyanamic pressure on the fairing falling to a specified amount.   The vehicle does not reach this until well into the burn of S2 and the rocket is only around 50km up at MECO. ( hence the lofted trajectory idea )   

The Atlas V S1 on the other hand, is likely around 100km high at MECO.  I would note that the Atlas V sequence after MECO is to start S2 and immediately jettison the fairing once S2 thrust is nominal.   The Atlas V vehicle has other problems with this concept that make it less interesting to consider.   The concept of the sliding fairing might work on the FH center core, since it will be throttled down and have a longer burn time, plus the side cores will be giving extra push to get it to a high altitude at center core MECO.   

I agree that some type of rail, plus bearings, would be needed to guide the fairing as it slides.   A stuck fairing in the wrong position would be loss of mission for the rocket.
Title: Re: Fairing reuse
Post by: Stan-1967 on 03/23/2016 03:01 PM
im not really following, but for an idea, perhaps following seperation using thrusters the two halves could quickly dock with one another to become one again.

Watch the animation from cambrianera in reply#200.   How would separate halves autonomously dock after jettison?  You will need more than thrusters. You would need to install a separate docking mechanisms, avionics & special software, laser/radar rangefinding gear?  I think it would be a long list of very complicated stuff. 

Title: Re: Fairing reuse
Post by: spacenut on 03/23/2016 03:48 PM
Fairing could also be attached to the second stage to protect the engine during reentry if and when a second stage is reused. 

Title: Re: Fairing reuse
Post by: Comga on 03/23/2016 05:26 PM
[sarcasm]They could just have Scotty beam them back to the HIF.[/sarcasm]

If fairings are not ejected, their mass takes away from the payload, possibly driving it negative.
We have seen payloads launched into "hydrosynchronous orbits" when fairings don't eject.

SpaceX is staging earlier than optimum to recover the first stage.  They are not going to stage later than optimum to be out of the atmosphere and try to include the fairing in the first stage recovery. edit: IMO

Fairing halves will stay separate once separated.  As Stan-1967 said, rejoining would be of overwhelming complexity.

How about we not come up with more Rube Goldberg systems and wait to see what SpaceX actually does?
Title: Re: Fairing reuse
Post by: Lar on 03/23/2016 06:01 PM
We tried the second stage as ship with cargo bay thing... didn't work that well... all of these fairing slides up and down ideas smack of that.

I agree with Comga, rather than doing what-if, why not try to figure out what SpaceX is doing and why and what things they are going to try next.  Some of the best threads on the site are those kind (the barge threads in many cases are like that)
Title: Re: Fairing reuse
Post by: sevenperforce on 03/23/2016 07:59 PM
Last I heard, FH will use FT side boosters but a v1.1 core. So SpaceX isn't averse to retaining multiple versions of the same stage for different purposes.

To that end, might SpaceX consider two versions of the upper stage -- one that is expendable with the current breakaway fairing, and one that is reusable with a clamshell PICA-X-covered fairing that opens around 30 degrees to release the payload, then locks? It's a payload cut, but it might be worthwhile for lower-mass payloads to LEO.

With the fairing locked out at 30 degrees, the upper stage would passively orient into a retrograde attitude, and the PICA-X layer on the locked fairing would absorb the brunt of the compressive heating. It would also result in a significantly lower terminal velocity, which is good for landing. Higher center of gravity, though, which is less good for landing.
Title: Re: Fairing reuse
Post by: Lar on 03/23/2016 08:50 PM
Last I heard, FH will use FT side boosters but a v1.1 core. So SpaceX isn't averse to retaining multiple versions of the same stage for different purposes.

Do you have a cite for that.. I doubt they are building v1.1 cores any more.

As to the rest, I think it much more interesting to try to figure out what SpaceX actually are up to near term. But that's just me.
Title: Re: Fairing reuse
Post by: spacenut on 03/23/2016 08:59 PM
Sorry, when I posted, I was thinking about the interstage between first and second stage, not the nose fairing.  What is wrong with dumping the fairings?  You can't save everything yet. 
Title: Re: Fairing reuse
Post by: sevenperforce on 03/23/2016 09:01 PM
Sorry, when I posted, I was thinking about the interstage between first and second stage, not the nose fairing.  What is wrong with dumping the fairings?  You can't save everything yet.
The fairings are hella expensive.
Title: Re: Fairing reuse
Post by: robert_d on 03/23/2016 09:05 PM
Has anyone considered going the other way with the Faring? By that I mean make it super cheap like the wrapping on a candy bar? I know there are aerodynamic loads and all that but just wondering if a dry nitrogen pressurized gas bag made out of some tough material could be used. After all NASA is investigating inflatables for potential reentry use, so maybe not so crazy? Just wondering.
Title: Re: Fairing reuse
Post by: mme on 03/23/2016 09:32 PM
Sorry, when I posted, I was thinking about the interstage between first and second stage, not the nose fairing.  What is wrong with dumping the fairings?  You can't save everything yet.
The fairings are hella expensive.
My understanding is that they take a long time to make, are big to store and it's hard to ramp up production.
Title: Re: Fairing reuse
Post by: Jim on 03/23/2016 09:38 PM
Has anyone considered going the other way with the Faring? By that I mean make it super cheap like the wrapping on a candy bar? I know there are aerodynamic loads and all that but just wondering if a dry nitrogen pressurized gas bag made out of some tough material could be used. After all NASA is investigating inflatables for potential reentry use, so maybe not so crazy? Just wondering.

there is a thread on this and reasons that it is not feasible.
Title: Re: Fairing reuse
Post by: Stan-1967 on 03/24/2016 03:42 AM
Has anyone considered going the other way with the Faring? By that I mean make it super cheap like the wrapping on a candy bar? I know there are aerodynamic loads and all that but just wondering if a dry nitrogen pressurized gas bag made out of some tough material could be used. After all NASA is investigating inflatables for potential reentry use, so maybe not so crazy? Just wondering.

It's not just aero loads.   The fairing shroud also provides an acoustic, thermal, chemical, & EMI environment that keeps the payload safe while waiting for launch as well as during ascent to orbit.  No cheap bag of gas is going to work for all those requirements.


 

Title: Re: Fairing reuse
Post by: HMXHMX on 03/24/2016 03:55 AM
Has anyone considered going the other way with the Faring? By that I mean make it super cheap like the wrapping on a candy bar? I know there are aerodynamic loads and all that but just wondering if a dry nitrogen pressurized gas bag made out of some tough material could be used. After all NASA is investigating inflatables for potential reentry use, so maybe not so crazy? Just wondering.

It's not just aero loads.   The fairing shroud also provides an acoustic, thermal, chemical, & EMI environment that keeps the payload safe while waiting for launch as well as during ascent to orbit.  No cheap bag of gas is going to work for all those requirements.



Apropos of that:  http://www.parabolicarc.com/2016/03/21/paragon-wins-nasa-sbir-phase-ii-contract-improved-inspace-transportation/#more-57831
Title: Re: Fairing reuse
Post by: dorkmo on 03/24/2016 04:23 AM
Fairing halves will stay separate once separated.  As Stan-1967 said, rejoining would be of overwhelming complexity.

i think you could potentially be trading one complex problem for a slightly less complex problem.

in a hypothetical world where joining the halves makes rentry significantly more survivable, i think youd want to consider it.

edit: and to satisfy the calls for realism. the new thrusters could enable a rejoining operation. plus they make a lot of docking hardware/software for dragon already.
Title: Re: Fairing reuse
Post by: robert_d on 03/24/2016 01:52 PM
Has anyone considered going the other way with the Faring? By that I mean make it super cheap like the wrapping on a candy bar? I know there are aerodynamic loads and all that but just wondering if a dry nitrogen pressurized gas bag made out of some tough material could be used. After all NASA is investigating inflatables for potential reentry use, so maybe not so crazy? Just wondering.

there is a thread on this and reasons that it is not feasible.
OK. Sorry, didn't realize there was another thread. At least the downthread comment by HMXHMX shows people are trying different concepts. Even I know that most of what is proposed here would be unworkable due to weight and complexity.

I would think they would start simple to see what could be done with the current fairing. What could stabilize it in at least one dimension for some period of time? Maybe add a small reel of ribbon to each half near the base and unreel it after separation. Like a kite tail. See if it will stabilize in pitch and maybe a bit in yaw. See how long the ribbon survives. Then if that gets anywhere, add a few deployable tabs that would autonomously adjust for roll. If those don't help, it seems that a far larger (he he he - Falcon 2 core) first stage would be required to have a much more massive system in place. Too complex and expensive.


 
Title: Re: Fairing reuse
Post by: sevenperforce on 03/24/2016 02:35 PM
I think you could potentially be trading one complex problem for a slightly less complex problem.

in a hypothetical world where joining the halves makes rentry significantly more survivable, i think youd want to consider it.

edit: and to satisfy the calls for realism. the new thrusters could enable a rejoining operation. plus they make a lot of docking hardware/software for dragon already.
All the active docking on Dragon V2 depends on the androgynous docking port. Not going to work in free-fall.

For second-stage reuse on lower-velocity missions with bulky payload requiring the fairing, the two fairing halves could be hinged, with struts connecting them to the landing legs. The fairing could be made more lightweight because the same opening mechanism is used for two different things. The landing legs would lock into place, maintaining the fairing halves firmly in a 30-degree open configuration. The two halves would thus feather like the hinged wings on SpaceShipOne, producing tremendous drag and distributing the heat flux very efficiently.

I attached a diagram to show how the overall sequence could work.

There are several major advantages. Rather than making the fairings sturdier to survive independent re-entry, the fairings can actually be made even lighter because they don't leave the vehicle. The heat redistribution is excellent and terminal velocity is much lower, placing less stress on the vehicle and requiring less dV. Recovery is in one piece and doesn't require retrieval of three different objects. Perhaps most importantly, this design means that the entire second stage can do a tiny burn at apogee and complete an entire orbit, then re-enter west of launch for a controlled RTLS landing. Finally, the greater weight of the fairing is a huge advantage with a suicide burn, as the T/W ratio is significantly lower.
Title: Re: Fairing reuse
Post by: Jim on 03/24/2016 02:55 PM
the fairings can actually be made even lighter because they don't leave the vehicle.

Can't say that.   Keeping them open and the landing loads would likely make them heavier than stand alone.
Title: Re: Fairing reuse
Post by: sevenperforce on 03/24/2016 03:26 PM
the fairings can actually be made even lighter because they don't leave the vehicle.

Can't say that.   Keeping them open and the landing loads would likely make them heavier than stand alone.
They aren't support structures.

Easier (from a weight basis) than making them reusable independently.
Title: Re: Fairing reuse
Post by: Jim on 03/24/2016 03:48 PM

They aren't support structures.

Easier (from a weight basis) than making them reusable independently.

Again, you have no data to support your claim.  All that might be needed to support independent reusability (as in standalone) is an attitude control system and parachute. 

Supporting the fairing on the stage partially open for entry and landing will require major reinforcement of the fairing.
Title: Re: Fairing reuse
Post by: sevenperforce on 03/24/2016 04:11 PM

They aren't support structures.

Easier (from a weight basis) than making them reusable independently.

Again, you have no data to support your claim.  All that might be needed to support independent reusability (as in standalone) is an attitude control system and parachute. 

Supporting the fairing on the stage partially open for entry and landing will require major reinforcement of the fairing.
Parachutes are heavy.

The reinforcement would primarily be needed for the landing legs, but they already need to be really strong.

Sure, I'm making educated guesses here, but it would be worth investigation.
Title: Re: Fairing reuse
Post by: RanulfC on 03/24/2016 04:12 PM
You're assuming a very narrow, and highly limited criteria for the concept;
"For second-stage reuse on lower-velocity missions with bulky payload requiring the fairing"

And the fairing would require structural additions to stand the heating and aero-loading of being attached to the seconds stage in a high-drag configuration. "Easier" than being reusable independently will not automatically translate to saving in weight. Your heat loading is going to be greater on the deployed legs AND you will have added aerodynamic problems with that configuration. (There are very good reasons why no one suggests deploying landing legs prior to reentry)

I'd actually question the idea of fairing reuse on an operational and economic basis because it only makes sense in either case if doing so costs (operationally AND financially) as close as possible to nothing beyond current costs. Trying to make everything on the F9 system "reusable" is gong to end up being self-defeating as the LV system is only an interim vehicle anyway. The architecture can only go so far before it runs into engineered in issues that limit it. (You lose the payload/upper-stage, and probably the vehicle in any abort/incident once its off the pad. Dragon/Dragon-2 are the only exceptions because any attempt at a similar LES abort system for unmanned payload will significantly detract from the payload itself)

Once you move to making the entire second stage reusable (and all that implies which includes things like fully INTACT abort modes for payload recovery during ALL aspects of flight, which is tough even when you START with a 'reusable' design and not a expendable one) you move sharply away from an interim vehicle and have to make significant modifications (as we've seen in these discussions) costing time, effort and money that directly subtracts from other programs.

If Elon and SpaceX are as focused on Mars as they seem to be then there is a point very close to where we are now where "good enough" is as far as you want to go with the Falcon-9 family, and instead focus on the next generation vehicle design which will be reusable from the start.

Randy
Title: Re: Fairing reuse
Post by: Jim on 03/24/2016 04:21 PM

Parachutes are heavy.

The reinforcement would primarily be needed for the landing legs, but they already need to be really strong.

More  (and heavy) reinforcements are needed for the fairing to handle to the additional loads that I list.
Title: Re: Fairing reuse
Post by: sevenperforce on 03/24/2016 06:00 PM
If they can allow for an additional SECO event, then what about having the fairing hinged at the nose? They could SECO, unhinge the thing and push it away with RCS, then restart the engine. It could then close on its own (or not, if re-entry characteristics were better).
Title: Re: Fairing reuse
Post by: robert_d on 03/25/2016 02:03 AM
Does anyone think it would be worth the cost of a bottom up test program as in dropping fairings with parachutes from airplanes to see if that end of things can be made to work? Seems to again lead to a lot of cost for questionable gains.
Title: Re: Fairing reuse
Post by: cscott on 03/25/2016 02:53 PM
SpaceX is already doing a test program, and its lift to altitude is free.  They get a test opportunity about once a month.  How can you beat that?
Title: Re: Fairing reuse
Post by: sevenperforce on 03/25/2016 03:19 PM
You know, if it would be possible to hinge the damn thing, why not simply hinge it along one long edge? Then it could open along that edge and tumble away still connected.
Title: Re: Fairing reuse
Post by: JasonAW3 on 03/25/2016 03:48 PM
You know, if it would be possible to hinge the damn thing, why not simply hinge it along one long edge? Then it could open along that edge and tumble away still connected.

Aerodynamics, while minimal at the altitudes that fairings are generally dropped from, would likely either bounce the fairing pairs back into the rocket, or simply tear them apart at the hinge.
Title: Re: Fairing reuse
Post by: JasonAW3 on 03/25/2016 03:53 PM

Parachutes are heavy.

The reinforcement would primarily be needed for the landing legs, but they already need to be really strong.

More  (and heavy) reinforcements are needed for the fairing to handle to the additional loads that I list.

What about an RCS system with a Ram-air Ballute?  Less issues with rigging and can be made fairly low mass.

     I'm not certain, but I think it might even be able to be made with a lower overall mass than a conventional parachute.
Title: Re: Fairing reuse
Post by: sevenperforce on 03/25/2016 04:56 PM
You know, if it would be possible to hinge the damn thing, why not simply hinge it along one long edge? Then it could open along that edge and tumble away still connected.

Aerodynamics, while minimal at the altitudes that fairings are generally dropped from, would likely either bounce the fairing pairs back into the rocket, or simply tear them apart at the hinge.
I thought the fairing was only jettisoned once it was far enough into space that there was no risk of harm to the payload from any aerodynamic effects.
Title: Re: Fairing reuse
Post by: cambrianera on 03/25/2016 05:42 PM
You know, if it would be possible to hinge the damn thing, why not simply hinge it along one long edge? Then it could open along that edge and tumble away still connected.
If you push a long edge hinged fairing over the other long edge, you get an inward movement of the hinge.
You can add a reaction beam to keep the hinge clear from the payload, but this would increase the mass of the fairing.
Title: Re: Fairing reuse
Post by: sevenperforce on 03/25/2016 11:41 PM
You know, if it would be possible to hinge the damn thing, why not simply hinge it along one long edge? Then it could open along that edge and tumble away still connected.
If you push a long edge hinged fairing over the other long edge, you get an inward movement of the hinge.
You can add a reaction beam to keep the hinge clear from the payload, but this would increase the mass of the fairing.
This is probably crazy, but what about manufacturing the fairing in three pieces rather than two: one the current size, then two 90-degree ones. Have the larger section hinge to both the other smaller sections so they open up like double doors.
Title: Re: Fairing reuse
Post by: NWade on 03/26/2016 07:16 AM
C'mon folks, this is all a bit ridiculous.  ??? You're forgetting a major issue: MASS
 
If you keep the fairing attached to the second stage you are having to accelerate a lot more mass up to your final velocity - plus carry it around for any maneuvering and de-orbit burns. And on top of that, having it hinged open or cantilevered out means your center of thrust may no longer be going through your center of mass - have fun with that! All of these things are tremendously wasteful and makes all of your operations harder. The best thing to do is keep the fairings as light as possible and jettison them as early as possible. The slower the rocket is going when you ditch them, the lower your re-entry energy is going to be (coming in from slower or a lower altitude, or both).
 
The K.I.S.S. principle applies, always.
 
--Noel
 
Title: Re: Fairing reuse
Post by: sevenperforce on 03/26/2016 11:54 AM
C'mon folks, this is all a bit ridiculous.  ??? You're forgetting a major issue: MASS
 
If you keep the fairing attached to the second stage you are having to accelerate a lot more mass up to your final velocity - plus carry it around for any maneuvering and de-orbit burns. And on top of that, having it hinged open or cantilevered out means your center of thrust may no longer be going through your center of mass - have fun with that! All of these things are tremendously wasteful and makes all of your operations harder. The best thing to do is keep the fairings as light as possible and jettison them as early as possible. The slower the rocket is going when you ditch them, the lower your re-entry energy is going to be (coming in from slower or a lower altitude, or both).
 
The suggestion of hingeing the fairing was to allow it to be jettisoned in one piece, not with the intent of carrying it to orbit.
Title: Re: Fairing reuse
Post by: Jim on 03/26/2016 01:07 PM
Hingeing would take too long to come off
Title: Re: Fairing reuse
Post by: OxCartMark on 03/27/2016 12:35 AM
Before we get too deep into designing this (which I think began a dozen or so pages back) can someone provide some numbers for pitot static pressure at that altitude and speed?  Maybe then with that we can do some slightly more educated guessmongering.
Title: Re: Fairing reuse
Post by: Arb on 03/27/2016 02:03 PM
Before we get too deep into designing this (which I think began a dozen or so pages back) can someone provide some numbers for pitot static pressure at that altitude and speed?  Maybe then with that we can do some slightly more educated guessmongering.

And if this is going to become a design thread it should be so renamed and a separate updates thread created for any news (official or otherwise) about what SpaceX are really doing...

Mods, please.
Title: Re: Fairing reuse
Post by: rickyramjet on 03/27/2016 03:42 PM
Before we get too deep into designing this (which I think began a dozen or so pages back) can someone provide some numbers for pitot static pressure at that altitude and speed?  Maybe then with that we can do some slightly more educated guessmongering.

And if this is going to become a design thread it should be so renamed and a separate updates thread created for any news (official or otherwise) about what SpaceX are really doing...

Mods, please.
How is this thread any different than the hundreds of others where NSFers make design suggestions in the absence of info from SpaceX?  Or, even in the absence of scientific knowledge? I say leave it as is!
Title: Re: Fairing reuse
Post by: cscott on 03/27/2016 05:54 PM
For the same reason many other threads on this site are split into "update" and "discussion" threads---some of us have much less patience for rube goldberg guesswork or (on other threads) concern trolling than others.
Title: Re: Fairing reuse
Post by: iamlucky13 on 04/01/2016 02:01 AM
You know, if it would be possible to hinge the damn thing, why not simply hinge it along one long edge? Then it could open along that edge and tumble away still connected.

That radically changes the separation dynamics, and not in a good way. As Orbital Sciences can attest, making a fairing separate reliably under thrust loads is not a trivial problem.

Sorry, when I posted, I was thinking about the interstage between first and second stage, not the nose fairing.  What is wrong with dumping the fairings?  You can't save everything yet.
The fairings are hella expensive.

I don't know if they're "hella" expensive, but they are significantly more expensive than I think most people realize. Apparently Ariane 5 fairings are around $6 million, and that's a similar size composite fairing. SpaceX might be doing theirs for cheaper, but even half that is still no small pile of pennies.
http://spacenews.com/41132ruag-books-order-for-18-ariane-5-fairings/

The fairing is certainly a lot less expensive than a first stage, but I suspect SpaceX is hoping it will prove one of the easiest parts to retrieve, so even if the value of the savings is not in the same ballpark as re-using a 1st stage, it might have a high return relative to the amount they have to invest developing the recovery technique.
Title: Re: Fairing reuse
Post by: JamesH65 on 04/01/2016 10:04 AM
 It does beg the questions of WHY they are so expensive. Anyone know?
Title: Re: Fairing reuse
Post by: rpapo on 04/01/2016 10:14 AM
It does beg the questions of WHY they are so expensive. Anyone know?
They're big, and they're composite.  The cost of making composite structures goes up rapidly with size, for a variety of reasons (material, tooling, processes required, difficulty in avoiding flaws, etc).
Title: Re: Fairing reuse
Post by: JamesH65 on 04/01/2016 01:24 PM
It does beg the questions of WHY they are so expensive. Anyone know?
They're big, and they're composite.  The cost of making composite structures goes up rapidly with size, for a variety of reasons (material, tooling, processes required, difficulty in avoiding flaws, etc).

Still, $6M seems a lot. Once you have the tooling in place, and have sorted the process and the QA, I would expect the price to drop fairly rapidly.
Title: Re: Fairing reuse
Post by: sevenperforce on 04/01/2016 02:26 PM
You know, if it would be possible to hinge the damn thing, why not simply hinge it along one long edge? Then it could open along that edge and tumble away still connected.

That radically changes the separation dynamics, and not in a good way. As Orbital Sciences can attest, making a fairing separate reliably under thrust loads is not a trivial problem.
What about something like this?

(http://s17.postimg.org/va7ysuhlr/fairing.png)

One seam, two hinges. Each hinge only needs 45 degrees of movement to provide full clearance; the imbalanced thrust loading immediately pulls the entire fairing off to the side opposite the seam. Spring-loading the hinges ought to provide a smooth enough and rapid enough deployment to clear the payload, and would be lighter than using a pneumatic system. You might need a puff of RCS to correct for the millisecond of imbalanced thrust on the rocket but given the mass of the rocket, fuel, and payload in comparison to the mass of the fairing the misalignment would be minuscule.

Assuming that the springs push the hinge into a locked position, the fairing would present a high surface area for re-entry and naturally align itself along an aerodynamic plane which protects the inside.
Title: Re: Fairing reuse
Post by: Jim on 04/01/2016 03:20 PM
1.  Spring-loading the hinges ought to provide a smooth enough and rapid enough deployment to clear the payload,

2. and would be lighter than using a pneumatic system.

3. You might need a puff of RCS to correct for the millisecond of imbalanced thrust on the rocket but given the mass of the rocket, fuel, and payload in comparison to the mass of the fairing the misalignment would be minuscule.


1.  What type of springs?  And how do you know they "ought" to?

2.  Based on what?  If no pneumatics, what pushes the fairing away?

3.  What RCS?

Do you know that the fairing separates while the vehicle is under thrust and still accelerating.

Also, the bottom of the fairing is disconnected at the same time as the seam splits.
Title: Re: Fairing reuse
Post by: Joffan on 04/01/2016 04:29 PM
Question - would it be possible to open the fairing between stage 1 MECO and stage 2 engine start, or is that still too low in the atmosphere for a typical payload? Would there be any issues with shedding the fairing either under no thrust or with the engine start-up thrust?

My expectation is that one of these issues is a deal-breaker for slightly earlier jettison of the fairing, but I don't know for sure...
Title: Re: Fairing reuse
Post by: Senex on 04/01/2016 04:47 PM
I just re-read the thread — leads me to the following points:

The fairing must be jettisoned.  Carrying the mass to orbit kills your payload capacity.  Not debatable.

The fairing has a large surface area and a low mass.  "Fluffy" recovery — less heating.  A whole different recovery mode from the second stage.  A paper airplane "dropped" from orbit will survive.  (See Japanese origami experiment - the problem is finding it!)

The shape of the half-fairings is a good approximation of a lifting body.  If you can organize the fairing's mass to put the centre of gravity in the right place it will "fly."  The trick may be initially stabilizing it in the correct attitude — which may be what SpaceX is working on.

They may be trying to figure out how much damage is from wave action.  Minor flotation bags and a beacon could help in recovering the fairing before it is damaged.

This should be doable — after some trial and error.  And they get a trial for "free" on every launch.
Title: Re: Fairing reuse
Post by: sevenperforce on 04/01/2016 05:35 PM
1.  Spring-loading the hinges ought to provide a smooth enough and rapid enough deployment to clear the payload,

2. and would be lighter than using a pneumatic system.

3. You might need a puff of RCS to correct for the millisecond of imbalanced thrust on the rocket but given the mass of the rocket, fuel, and payload in comparison to the mass of the fairing the misalignment would be minuscule.


1.  What type of springs?  And how do you know they "ought" to?

2.  Based on what?  If no pneumatics, what pushes the fairing away?

3.  What RCS?

Do you know that the fairing separates while the vehicle is under thrust and still accelerating.

Also, the bottom of the fairing is disconnected at the same time as the seam splits.
Outward-opening hinges mounted on the inside. Steel springs, I assume. I'm saying they could be designed to open smoothly and rapidly enough.

The fairing would be pushed away by the continued acceleration of the vehicle; as soon as the springs opened, the center of mass would shift and cause differential force on the fairing. You would need only one pneumatic clip holding the two doors together and fixed to the second stage body; once that clip retracts, the doors swing open and acceleration takes care of the rest.

I was talking about the RCS on the upper stage being used to correct the stage misalignment due to the momentary COM shift.
Title: Re: Fairing reuse
Post by: RDoc on 04/01/2016 05:46 PM
I just re-read the thread — leads me to the following points:

The fairing must be jettisoned.  Carrying the mass to orbit kills your payload capacity.  Not debatable.

The fairing has a large surface area and a low mass.  "Fluffy" recovery — less heating.  A whole different recovery mode from the second stage.  A paper airplane "dropped" from orbit will survive.  (See Japanese origami experiment - the problem is finding it!)

The shape of the half-fairings is a good approximation of a lifting body.  If you can organize the fairing's mass to put the centre of gravity in the right place it will "fly."  The trick may be initially stabilizing it in the correct attitude — which may be what SpaceX is working on.

They may be trying to figure out how much damage is from wave action.  Minor flotation bags and a beacon could help in recovering the fairing before it is damaged.

This should be doable — after some trial and error.  And they get a trial for "free" on every launch.

This is my view as well, but with the addition of some control surfaces and flight computers.
Title: Re: Fairing reuse
Post by: cambrianera on 04/01/2016 05:54 PM
@sevenperforce,
once your “doors“ open, the center of mass of the system follow the movement of the doors.
Moreover the doors are loosing their stand on the second stage.
The result is the fairing collapsing on the payload.
Title: Re: Fairing reuse
Post by: The Amazing Catstronaut on 04/01/2016 06:20 PM
You can reuse a fairing with a normal fairing separation, indeed, you should be. Fairings ain't broke and are a fairly rare failure mode if your quality assurance is indeed assured. It works, it's optimal, we should focus our attention on what the fairing is doing once detached from the structure of the rocket.

I've always been of the opinion giving the fairing a few thrusters to orient itself, a (light) parafoil, a GPS, and then scooting the the fairing out of the air SMART reuse/CORONA style is the right idea. You can do shebang without adding a ridiculous amount of mass, although you are going to have to accept a certain minor amount of performance loss.

I don't know if they're actually doing that. To me the idea seems sensible enough I have the feeling I've heard it somewhere before. Unsure. I didn't read the whole thread nor have I read too deeply into it.

Edit: And after looking back in the thread it seems that idea has been suggested before and I even replied to it. Doh!
Title: Re: Fairing reuse
Post by: sevenperforce on 04/01/2016 07:34 PM
@sevenperforce,
once your “doors“ open, the center of mass of the system follow the movement of the doors.
Moreover the doors are loosing their stand on the second stage.
The result is the fairing collapsing on the payload.
Then add a vertical bearing arm to the inside of the upper stage coupler to hold the fairing in place until the COM shifts far enough out.
Title: Re: Fairing reuse
Post by: Jim on 04/01/2016 09:09 PM

The fairing would be pushed away by the continued acceleration of the vehicle;

Fairings aren't pushed away by the vehicle.  They are detached at the base at the same time as the seams open and are pushed away by a pneumatic system or ordnance.

You would need only one pneumatic clip holding the two doors together and fixed to the second stage body;

Fairings use many bolts or devices (more than 5 and some in the tens) to hold them together.

Outward-opening hinges mounted on the inside. Steel springs, I assume. I'm saying they could be designed to open smoothly and rapidly enough.


To generate the forces and the acceleration required, they would have to huge and hence heavy

This is how fast a fairing comes off

https://www.youtube.com/watch?v=Fvte4KfEWGI
Title: Re: Fairing reuse
Post by: CyndyC on 04/02/2016 04:59 PM
Along with the video Jim posted, this video of a SpaceX fairing separation test might help with the brainstorming:

https://www.youtube.com/watch?v=LtI1V624vWM
Title: Re: Fairing reuse
Post by: D_Dom on 04/02/2016 06:54 PM
Thank you Jim and CyndyC! I really enjoy good high speed imagery, it helps me understand the forces involved. The Atlas fairing flex as it separates for example. The SpaceX chamber test demonstrates their fine tuned inertia absorbing system, just amazing.
Title: Re: Fairing reuse
Post by: chalz on 04/04/2016 03:44 AM
Suppose you wanted to add a parachute to try to make a fairing more survivable. Where on the fairing would you put it? Could the pushers handle the extra weight and would a change in CG affect the opening motion? I'm thinking they might have to attach a parachute halfway up the outside. Drill some holes in it and bolt it to it, maybe 100kg extra. Also perhaps a buoyancy aid will be necessary for the post splashdown procedure but SpaceX won't find that out until they can get one down in one piece.
Title: Re: Fairing reuse
Post by: Stan-1967 on 04/04/2016 06:24 AM
The problem of fairing reuse is really lacking a problem statement(s) to drive potential solutions.

Take for example the problem of precision landing hoverslams:
1.  Pioneer the work to execute hypersonic retropulsion
2.  Slow the stage to "x" meters/sec., +- some value "y", at elevation "A"
3.  perform #2 velocity change with "M1" kg's of fuel and oxidizer.
4.  perform #2 & #3 above with +- 15 meters accuracy to a predetermined latitude/longitude coordinate
5.  Do all the above, but don't land at an angle and tip over and explode, don't break a leg and tip over and explode, don't have horizontal velocity and hit the barge and explode, don't run out of fuel and explode, etc. etc.

My point being is that the hoverslam maneuver first defined the vehicle orientation, stability, velocity change requirements, navigation requirements, and load tolerance requirements before SpaceX added all the systems that adapted mass trade-offs against them. ( i.e grid fins, landing legs, ASDS vs. RTLS, etc. )

So for fairing reuse, what are the problems?   How do they limit ( or eliminate ) the possible solutions?

Here is what I can come up with:
1.  The fairing needs to be slowed to a speed that does not fracture the composite structure no matter the orientation at impact.  ( let imaginations flow if this is to be done with parachutes, active flight control surfaces deployed, sliding the fairing down the side of S1 prior to MECO, rocket retropropulsion aka Soyuz capsule etc.)

2.  Methods proposed in #1 cannot jeopardize the payload, or be less reliable than existing disposable fairings.

3.  Landing accuracy needs to occur in a specified landing ellipse or search grid that is a 100X smaller area than a ballistic reentry with unstable aerodynamics.  Want a bigger margin for area?  How will you search it before winds & currents expand the search area to unmanagable proportion?

4.  The fairings cannot be left in the ocean for extended search times in excess of 24-36 hours.  Again want more time? fine, how will you home in on the fairing when wind, current, weather, and search resources make recovery moot.

5.  Allowable extra mass is 1000kg per half.   This addition penalizes S1 about 9200 kg's of extra fuel that cannot be used for RTLS or DPL, not to mention less mass to orbit.  If you want a bigger mass budget, fine.  It comes at the expense of S1 reuse probability, and could be the difference between RTLS or DPL, not to mention success or failure of S1 reuse.  If you can propose some method using less mass, great! Better chance for S1 re-use.
Title: Re: Fairing reuse
Post by: bioelectromechanic on 04/04/2016 12:58 PM
How much does it weight? dimensions? surface area? how much additional mass would systems require? will it require a change in the F9 flight profile? what is dV cost of the flight profile change?
Title: Re: Fairing reuse
Post by: cambrianera on 04/04/2016 08:06 PM

So for fairing reuse, what are the problems?   How do they limit ( or eliminate ) the possible solutions?


Nice post, I would like to add my comment.

Let me start with #2:
Would we discuss addition/tweaks to existing disposable fairings to avoid too many variables? This also not jeopardizes payload nor worsen reliability.

#1 Orientation is paramount, going convex first you can spread conveniently the shock wave at the atmospheric interface, then going concave first when subsonic you can slow down under 20 m/s of terminal velocity. I see deployable panels for convex first, and midsize drogues/parachutes for concave first.

#3 Radio beacons?

#4 Agree on search time, I think would be enough w radio beacon.

#5 I will start the "guesstimate" phase soon, but let me say 1000 kg is too much. Not more than 300 kg per half to avoid compounding effects on the fairing itself (more mass, more structure and so on)

Title: Re: Fairing reuse
Post by: Lars-J on 04/04/2016 08:20 PM
All this "fairing reuse" talk seems to be misleading. You don't want that. What you actually want - but somehow refuse to call it - is a payload bay with doors that can open and close. (like on Shuttle)

It's a certainly doable and a good idea for a reusable upper stage, but it will weigh significantly more and be a lot more complex. You need a lot of mass margin to pull it off.

(An upper stage with an integrated cargo bay is what I have been advocating for commercial BFR use, where margins would be plentiful)

But don't think of it is a "reused fairing". Think of it as a payload bay - it is a far more realistic approach.
Title: Re: Fairing reuse
Post by: OxCartMark on 04/04/2016 09:25 PM
All this "fairing reuse" talk seems to be misleading. You don't want that. What you actually want - but somehow refuse to call it - is a payload bay with doors that can open and close. (like on Shuttle)

It's a certainly doable and a good idea for a reusable upper stage, but it will weigh significantly more and be a lot more complex. You need a lot of mass margin to pull it off.

(An upper stage with an integrated cargo bay is what I have been advocating for commercial BFR use, where margins would be plentiful)

But don't think of it is a "reused fairing". Think of it as a payload bay - it is a far more realistic approach.

Then you'd be taking it all the way up and as has been hashed and re-hashed above won't work because taking the current fairing along for the whole ride cuts your payload to orbit in half and you're talking about making it weigh more and then taking it to orbit.  And not only do you pay the mass penalty once going up but you've also added more energy to the second stage that needs to be dissipated on the way down with thrust and with heating.  And, since under the scenario you propose it would have to survive re-entry at many times the speed that it currently hits at it would need to be made structurally stouter (heavier) to survive and would need a heat shield (more weight) if it is even possible to make a heat shield work on a piece of plastic.  My seat of the pants feel is that you'd reduce the payload to orbit to 1000 pounds but I may be off by a few thousand pounds and maybe it wouldn't be capable of going that fast.
Title: Re: Fairing reuse
Post by: savuporo on 04/04/2016 09:46 PM
Not sure if this is feasible or buys you anything much, but one could envision a system where separated sides fairing will remain connected via a tether. Definitely would require extra pyrotechnics to make the separation clean - and separation is risky as it is.
Title: Re: Fairing reuse
Post by: Jdeshetler on 04/05/2016 03:22 AM
Speed up the slow motion of SpaceX fairing separation test back to "real time".
It moved faster than the test straps that is holding it.

https://www.youtube.com/watch?v=k0MziXDlblU

This is how fast a fairing comes off
Title: Re: Fairing reuse
Post by: Stan-1967 on 04/05/2016 04:58 AM
Not sure if this is feasible or buys you anything much, but one could envision a system where separated sides fairing will remain connected via a tether. Definitely would require extra pyrotechnics to make the separation clean - and separation is risky as it is.

Why is my brain having images of "Space Clackers"?

https://www.youtube.com/watch?v=7leq3vn8P3A

But seriously, to what effect would the tether do anything useful?  What benefit is derived from this?   What do you want to do with two fairing halves connected with a tether?
Title: Re: Fairing reuse
Post by: Stan-1967 on 04/05/2016 06:01 AM

snip...

#1 Orientation is paramount, going convex first you can spread conveniently the shock wave at the atmospheric interface, then going concave first when subsonic you can slow down under 20 m/s of terminal velocity. I see deployable panels for convex first, and midsize drogues/parachutes for concave first.

#3 Radio beacons

 snip...


As to radio beacons, I think that not only could the fairings be instrumented with either radio beacons, but also sono emitters that could be picked up and triangulated with prepositioned sonobouys in the landing zone.  The tough part is still getting to a landing zone.

I get the convex/concave choices for managing shock and drag, but I am not sure a fairing (half) can maintain attitude control during re-entry, or during decent at terminal velocity.   Are you certain of the stability?  I do not know.   

It looks like it would have dynamic instability and tumble, roll, & spin all over the place.  Indeed I think figuring out the existing stability characteristics is a good starting point.  At the simple end of the spectrum, maybe a drogue chute can fix it, if that doesn't do the job, move on to deployable passive control surfaces, then active surfaces. 


I had another idea for stability.   Imagine the inside of each fairing to have a bladder ( thin rubber/plastic/composite?) lightly adhered ( think 3M yellow stick notes type of adhesion) to the inside surface of the composite fairing shell.   All the anechoic foams,insulation, & active sonic devices are layered on top of this bladder, and continue to perform the functions needed for the fairing environment.   The fairing can look and work just as the existing items currently do.

When the fairing is jettisoned, a COPV attached inside the fairing half will inflate the bladder, and the pressure of the gas will peel the bladder away from the inside of the fairing and inflate to a form that mirrors the composite fairing half, and once inflated the fairing will have virtually the same shape as a full fairing.  Most of the anechoic foams/insulation will pop off during this event.

What next?   I might want to try and spin it up for some stability, or I might try to have some passive aero surfaces spin it.   Whatever the method ( passive surfaces or drogue chute ) it takes to impart stability, that is what I want to solve.  The reason is so that it follows a stable ballistic trajectory, no tumbling, surfing, or gliding all over the downrange ocean.    This minimizes the area of the landing zone, and enables location and recovery.   At some point, maybe 2000'-3000' above sea level, it would deploy a chute for a soft landing at some angle on it's side, and preferably with the gas bladder impacting the ocean first. (like an airbag softening the impact)

Title: Re: Fairing reuse
Post by: JamesH65 on 04/05/2016 09:13 AM

snip...

#1 Orientation is paramount, going convex first you can spread conveniently the shock wave at the atmospheric interface, then going concave first when subsonic you can slow down under 20 m/s of terminal velocity. I see deployable panels for convex first, and midsize drogues/parachutes for concave first.

#3 Radio beacons

 snip...


As to radio beacons, I think that not only could the fairings be instrumented with either radio beacons, but also sono emitters that could be picked up and triangulated with prepositioned sonobouys in the landing zone.  The tough part is still getting to a landing zone.


Isn't the obvious route for location to simple have a GPS + satellite link on board that transmits its exact location in real time? Cost and weight minimal, accuracy within 1m.
Title: Re: Fairing reuse
Post by: Jim on 04/05/2016 11:33 AM

When the fairing is jettisoned, a COPV attached inside the fairing half will inflate the bladder, and the pressure of the gas will peel the bladder away from the inside of the fairing


How are you going to keep it in place and yet make inflation "peel" it off.
Title: Re: Fairing reuse
Post by: Stan-1967 on 04/05/2016 01:54 PM

When the fairing is jettisoned, a COPV attached inside the fairing half will inflate the bladder, and the pressure of the gas will peel the bladder away from the inside of the fairing


How are you going to keep it in place and yet make inflation "peel" it off.

Peeling it off is going to be an important trick.   I think adhesives engineered like this one would be candidates.

http://solutions.3m.com/wps/portal/3M/en_US/Adhesives/Tapes/Products/~/3M-Repositionable-75-Spray-Adhesive-Net-Wt-10-25-oz-12-per-case?N=5396314+4294924311&rt=rud

This class of adhesives have a storied past regarding the 3M Post-it-notes, however the adhesive can be engineered to adjust the strength/holding properties, but more importantly, the peel strength properties.   It needs to be strong enough to hold all the inner linings materials and insulation of the fairing to the bladder.   If you look at the mass of the fairing materials, and the very large surface area of the inside of the composite fairing shell, the holding strength is not very large in terms of Newtons/cm^2.   The peel strength probably the more critical property.   You need to get the inside of the bladder lifted from a small corner or edge, and then "unzip" the entire length of the assembly.
Title: Re: Fairing reuse
Post by: savuporo on 04/05/2016 03:43 PM
But seriously, to what effect would the tether do anything useful?  What benefit is derived from this?   What do you want to do with two fairing halves connected with a tether?
You could have the tether reel in a few seconds after clean separation, pulling the sides together. This might make the reentry tumble more survivable, or worse. No idea - just an idle thought
Title: Re: Fairing reuse
Post by: cambrianera on 04/05/2016 07:00 PM
But seriously, to what effect would the tether do anything useful?  What benefit is derived from this?   What do you want to do with two fairing halves connected with a tether?
You could have the tether reel in a few seconds after clean separation, pulling the sides together. This might make the reentry tumble more survivable, or worse. No idea - just an idle thought
I thought to that. Fishing reels are reliable, small mass, small friction devices that can be modified on purpose.
Still remaining important issues:
-risk of tangling into payload (or between tethers, if more than one);
-rejoining of halves to be completed by other devices (hooks, clamps or similar);
-terminal velocity probably too high to survive sea impact (need some other device).

Assuming the same mass, obviously separate halves have smaller mass/surface ratio.

Title: Re: Fairing reuse
Post by: llanitedave on 04/05/2016 07:02 PM
The fairing is not that heavy, and it's already relatively robust as it is.  I think it might not need anything more than a small drogue chute and a homing device, at least for starters.
Title: Re: Fairing reuse
Post by: cambrianera on 04/05/2016 07:11 PM

I had another idea for stability.   Imagine the inside of each fairing to have a bladder ( thin rubber/plastic/composite?) lightly adhered ( think 3M yellow stick notes type of adhesion) to the inside surface of the composite fairing shell.   All the anechoic foams,insulation, & active sonic devices are layered on top of this bladder, and continue to perform the functions needed for the fairing environment.   The fairing can look and work just as the existing items currently do.

When the fairing is jettisoned, a COPV attached inside the fairing half will inflate the bladder, and the pressure of the gas will peel the bladder away from the inside of the fairing and inflate to a form that mirrors the composite fairing half, and once inflated the fairing will have virtually the same shape as a full fairing.  Most of the anechoic foams/insulation will pop off during this event.


Intriguing idea, but I see a couple of important drawbacks:
-mass. The bladder should have some structural integrity, otherwise should not stand the stresses of peeling, mantaining a pressure enough to stabilize against airflow and finally splashdown; this having the same surface as a fairing half.
-reusability. You basically throw away all the internal parts of the fairing, moreover you have to reapply the bladder to the half fairing (assuming the bladder itself can be reused).
Title: Re: Fairing reuse
Post by: savuporo on 04/05/2016 07:20 PM
-risk of tangling into payload (or between tethers, if more than one);
If you had three sided fairing, tangling potential could be maybe smaller, if there are three tethers connecting the corners. Hard to clear the rocket with two-halve clamshell fairing, would need extra pyro gear or something
Title: Re: Fairing reuse
Post by: cambrianera on 04/05/2016 07:46 PM
-risk of tangling into payload (or between tethers, if more than one);
If you had three sided fairing, tangling potential could be maybe smaller, if there are three tethers connecting the corners. Hard to clear the rocket with two-halve clamshell fairing, would need extra pyro gear or something

True, but three sided fairings should call for more joints, more pushers, more mass overall.
But not a given, maybe interesting.
Tangling of the tethers still remain a possibility, and rejoining three pieces requires more effort.
Title: Re: Fairing reuse
Post by: cambrianera on 04/05/2016 07:49 PM

I get the convex/concave choices for managing shock and drag, but I am not sure a fairing (half) can maintain attitude control during re-entry, or during decent at terminal velocity.   Are you certain of the stability?  I do not know.   


Thinking to something like this, very light.
For first part, reentry, managing the shock
Title: Re: Fairing reuse
Post by: CraigLieb on 04/05/2016 08:21 PM
How about the fairings split into 28.3 degree sections, sprout little wings,  with small jet engines that pop out, and fly themselves independently down to a specially designed run-way like a mini-shuttle?   ::)
Please no serious replies.  This was meant as a joke to point out how little value there is in trying to engineer a solution here.
Title: Re: Fairing reuse
Post by: llanitedave on 04/05/2016 11:37 PM
Perhaps if we built a large, wooden badger...



Title: Re: Fairing reuse
Post by: sewebster on 04/06/2016 02:13 AM
Then you'd be taking it all the way up and as has been hashed and re-hashed above won't work because taking the current fairing along for the whole ride cuts your payload to orbit in half and you're talking about making it weigh more and then taking it to orbit.  And not only do you pay the mass penalty once going up but you've also added

Not that I'm advocating for taking the fairing to orbit, but does it really have a mass of half the payload? Do we know the mass? (maybe I just forget from upthread...)
Title: Re: Fairing reuse
Post by: D_Dom on 04/06/2016 02:22 AM
The weight of the fairing must be overcome by burning rocket fuel. The mass of the fuel is dictated by the rocket equation. It is not that mass of the fairing is equal to half the payload, it is the tyranny of the rocket equation that cuts the payload mass if you carry the fairing further than absolutely necessary.
Title: Re: Fairing reuse
Post by: sewebster on 04/06/2016 02:41 AM
The weight of the fairing must be overcome by burning rocket fuel. The mass of the fuel is dictated by the rocket equation. It is not that mass of the fairing is equal to half the payload, it is the tyranny of the rocket equation that cuts the payload mass if you carry the fairing further than absolutely necessary.

Right, but presumably the worst case scenario is subtracting the fairing mass from the maximum payload mass (if you take the fairing to orbit)? In reality it isn't this bad, because you were already planning on taking the fairing up part of the way?
Title: Re: Fairing reuse
Post by: savuporo on 04/06/2016 02:53 AM
Right, but presumably the worst case scenario is subtracting the fairing mass from the maximum payload mass (if you take the fairing to orbit)? In reality it isn't this bad, because you were already planning on taking the fairing up part of the way?
Its this bad, as fairing separates roughly after 1/3rd of the flight time. For the rest of the 2/3rd of flight, you are not trying to accelerate that weight.
Title: Re: Fairing reuse
Post by: OxCartMark on 04/06/2016 02:48 PM
In my opinion the combined productive benefit of the preceding 15 pages is about as useful to human endeavor as a parachute on a well driller.
Title: Re: Fairing reuse
Post by: Lar on 04/06/2016 04:26 PM
Mod here: I've been trying to figure out how to split out the "what they could do" from "what we think... based on evidence, that SpaceX IS doing". I couldn't find a good set of posts to split out, but I'm trying.

Maybe the way to go is to start a new thread that focuses only on the evidence, and stays narrowly focused, and leave this thread for those folks that want to come up with ever wilder schemes.... (not me, so much, I'm more interested in the kremlinology around what SpaceX appears to actually be doing)  I will continue to try to find a way to split but if not, will lock this, and start two threads.
Title: Re: Fairing reuse
Post by: dorkmo on 04/06/2016 10:27 PM
known spacex advances:
thrusters to control orientation
go pros to record fall
possible extra recovery ship
a few statements about recovery intentions
?

i vote for one thread to speculate at will. its not perfect but we dont have much to go on in the first place.
(says the guy that thinks they could dock the two halves together lulz)
Title: Re: Fairing reuse
Post by: llanitedave on 04/06/2016 10:42 PM
Maybe we need a fairing Bingo thread.
Title: Re: Fairing reuse
Post by: wannamoonbase on 04/07/2016 12:28 AM
known spacex advances:
thrusters to control orientation
go pros to record fall
possible extra recovery ship
a few statements about recovery intentions
?

i vote for one thread to speculate at will. its not perfect but we dont have much to go on in the first place.
(says the guy that thinks they could dock the two halves together lulz)

This whole development is exciting and interesting.  They'll likely proceed incrementally and slowly and we won't know how far they are until they succeed.  I'd bet they start with recovering one half first.

With all the developments they have going on, if they try hooking one in the next year that would be pretty quick in my opinion.
 
Title: Re: Fairing reuse
Post by: cscott on 04/07/2016 02:45 PM
I like the two thread idea.  It's obvious (to me) that SpaceX is recovering the fairing halves individually, and is experimenting with RCS mechanisms to stabilize them.  The outlandish clamshell and tether ideas here have no evidence supporting them -- putting aside completely the question of their practicality, superiority, etc.  Sign me up for the low-volume thread discussing actual *evidence* and theories grounded in that evidence.  I have no problem with folks continuing to try to "build a better mousetrap"... I'm just not personally interested in following that thread.

Ob. Fairing news: in the ASDS thread we've noticed that Go Searcher, who has gone out for recovery attempts involving fairings, is staying in port for the dragon launch (which doesn't involve a fairing).  We'll see if this pattern holds, but it's beginning to look like evidence for a "fairing recovery" role for Go Searcher.
Title: Re: Fairing reuse
Post by: D_Dom on 04/07/2016 04:09 PM
Huge benefit to people unfamiliar with the statement "space is hard" is that on this site you can ask any questions you like and expect a responsible answer. Agreed that some of the topics on this thread defy all the known laws of physics, so be it. Also thinking of channeling Jim for one word responses if only just to increase the number of replies I have time for. Not at all offended by having to wade through the outlandish ideas to consider the "evidence". My humble opinion is leave it as one thread, cultivate the signal, address the noise (respectfully) and we may all learn something about this most interesting aspect of re-usability.
Title: Re: Fairing reuse
Post by: Space Ghost 1962 on 04/07/2016 04:16 PM
... and do your own reading/searching/research on the substantial body of what has been attempted already.

For example, Kistler K-1 was to be a TSTO 100% reusable vehicle, which had ... a kind of fairing that was reused.

Also, keep in mind that some conceived ideas change as you take a concept and put it into action. For example, Dragon's solar panels were encased inside the trunk and a complex articulation of booms deployed them - never flown - they chose to mount them on the side for a simpler deploy with jettisoned fairings.

Ask yourself "why" these decisions were/are made first. Think of the trades for each.
Title: Re: Fairing reuse
Post by: D_Dom on 04/07/2016 04:27 PM
In my opinion the combined productive benefit of the preceding 15 pages is about as useful to human endeavor as a parachute on a well driller.

Having jumped out of perfectly good airplanes before I can see the advantage of "dropping in" heavy equipment to a remote site. just saying...
Title: Re: Fairing reuse
Post by: manoweb on 04/08/2016 11:15 PM
Today at the press debriefing Mr. E. Musk mentioned they are pursuing fairing reuse, because it costs several million dollars.
Title: Re: Fairing reuse
Post by: Mader Levap on 04/08/2016 11:17 PM
Today at the press debriefing Mr. E. Musk mentioned they are pursuing fairing reuse, because it costs several million dollars.
Wouldn't that be first official mention of fairing reuse?
Title: Re: Fairing reuse
Post by: mlow on 04/08/2016 11:20 PM
The way I heard it, sounded like he was referring to couple mil each.
Title: Re: Fairing reuse
Post by: iamlucky13 on 04/09/2016 02:58 AM
Yes, and estimated costs in the $5-6 million range for the similarly sized Ariane 5 fairing, which is also composite, have been documented further up thread. Fairings are more complicated structures than most people realize.

I'm pretty sure this is the first public mention of fairing recovery plans.
Title: Re: Fairing reuse
Post by: leetdan on 04/09/2016 05:34 AM
Today at the press debriefing Mr. E. Musk mentioned they are pursuing fairing reuse, because it costs several million dollars.
Wouldn't that be first official mention of fairing reuse?

Fairing reuse has been mentioned in response to people posting images of fairing fragments washing up elsewhere.

My questions is, have we officially heard anything about thrusters on the fairing?  I know people 'saw something' in the SES-9 launch videos, but has SpaceX ever confirmed what we were seeing?
Title: Re: Fairing reuse
Post by: meekGee on 04/09/2016 06:05 AM
Today at the press debriefing Mr. E. Musk mentioned they are pursuing fairing reuse, because it costs several million dollars.
Wouldn't that be first official mention of fairing reuse?

Fairing reuse has been mentioned in response to people posting images of fairing fragments washing up elsewhere.

My questions is, have we officially heard anything about thrusters on the fairing?  I know people 'saw something' in the SES-9 launch videos, but has SpaceX ever confirmed what we were seeing?
There was informal but credible info on L2 for a while now.
Title: Re: Fairing reuse
Post by: mikelepage on 04/09/2016 10:25 AM
Some "fairing blimp" calculations: feel free to skip.

Coming over from the airship thread, and reading upthread about the potential for having some kind of bladder on the inside of the fairing, I just wanted to do a back of the envelope on the possibility of converting each fairing half into a lighter-than-air craft before it reaches the ground.  Could inform potential Venus airship mission too.

Total fairing weight for the 13.1x5.2m ("bus containing") is supposed to be 1750kg.  Dividing that by 2 gives 875kg per half:
Pre-empting the results below, I'm assuming we're adding 225kg per half to take it to 1100kg per half:

1) Amount of Helium required to provide equivalent buoyancy force:
Each mole of Helium is 4 grams, displaces ~29g of atmosphere, and expands to 22.4 L at STP.
1100000g fairing half/ 25g = 44000 moles of helium (176kg).
At STP that would fill a bladder to ~985.6m3 (call it 1000m3)

2) Assuming the bladder expands to a cylinder 13.1m long capped with hemispheres
V = 4/3πr3 + 26.2πr
r ~ 5.2 m

3) Surface area of inflated bladder
5.2π*13.1+ 4π(5.2)2 = 340m2
Standard blimp envelope material seems to be 80-90g per m2
giving us 30.6kg of envelope material.

Not really sure of the weight/size requirements of the helium gas canister you'd need, but it seems to me this could be within the realms of workability, if you can have some kind of drogue chute that would keep the fairing somewhat oriented to protect the bladder material on the way down.
Title: Re: Fairing reuse
Post by: Radical_Ignorant on 04/09/2016 10:54 AM
Many  here like the idea of keeping both pieces connected and closing them before reentering atmosphere. I find it compelling as connected they create shape which seems to be much more stable. And easier to keep afloat.

And how to keep them connected? Well, I see on the video were they test separation mechanism that both parts are connected, so it seems possible. And in old days there were those rockets controlled by cables, so there are things which can survive and do the job.

But then is it required at all? Pieces found are pretty large, so maybe it's enough to reduce impact speed (with water) by small parachute and no need anything more than orienting it on the start to protect the parachute from burning in initial phase.

But still I'm intrigued if connection as on test video could be used with some minor modifications in real mission.
Title: Re: Fairing reuse
Post by: Jim on 04/09/2016 01:49 PM

And how to keep them connected? Well, I see on the video were they test separation mechanism that both parts are connected, so it seems possible. And in old days there were those rockets controlled by cables, so there are things which can survive and do the job.


not true on either point.  The cables would put loads on the fairings and there is no way to bring them together in a controlled matter without them slamming together.

Which rockets were controlled by cables?
Title: Re: Fairing reuse
Post by: tyrred on 04/09/2016 03:25 PM
May be a reference to TOW missiles (Tube-launched Optically tracked Wire-guided)?
Title: Re: Fairing reuse
Post by: Radical_Ignorant on 04/09/2016 04:31 PM

And how to keep them connected? Well, I see on the video were they test separation mechanism that both parts are connected, so it seems possible. And in old days there were those rockets controlled by cables, so there are things which can survive and do the job.


not true on either point.  The cables would put loads on the fairings and there is no way to bring them together in a controlled matter without them slamming together.

Which rockets were controlled by cables?

Of course that they would put loads, and so? This load would be symetric, fairings would be tiny bit heavier.
No way to bring them together? You mean that it's impossible to control  force required to pull the cable? Or you say that using force in only one way it's not possible to gently stop momentum? Like for example on rocket falling from the sky? Or you claim that TOWs (thanks tyrred - I was lazy) weren't working because there is no cable which could easily withstand rocket exhaust?

It's always super easy to claim "no it's impossible". But that's rarely true. That would be too hard, or that would not be cost effective, or that could be dangerous/not reliable because of... that I could believe.
Title: Re: Fairing reuse
Post by: llanitedave on 04/09/2016 04:53 PM

And how to keep them connected? Well, I see on the video were they test separation mechanism that both parts are connected, so it seems possible. And in old days there were those rockets controlled by cables, so there are things which can survive and do the job.


not true on either point.  The cables would put loads on the fairings and there is no way to bring them together in a controlled matter without them slamming together.

Which rockets were controlled by cables?

Of course that they would put loads, and so? This load would be symetric, fairings would be tiny bit heavier.
No way to bring them together? You mean that it's impossible to control  force required to pull the cable? Or you say that using force in only one way it's not possible to gently stop momentum? Like for example on rocket falling from the sky? Or you claim that TOWs (thanks tyrred - I was lazy) weren't working because there is no cable which could easily withstand rocket exhaust?

It's always super easy to claim "no it's impossible". But that's rarely true. That would be too hard, or that would not be cost effective, or that could be dangerous/not reliable because of... that I could believe.


How about "it's simply unnecessary."
Title: Re: Fairing reuse
Post by: Stan-1967 on 04/09/2016 05:42 PM

And how to keep them connected? Well, I see on the video were they test separation mechanism that both parts are connected, so it seems possible. And in old days there were those rockets controlled by cables, so there are things which can survive and do the job.


not true on either point.  The cables would put loads on the fairings and there is no way to bring them together in a controlled matter without them slamming together.

Which rockets were controlled by cables?

Of course that they would put loads, and so? This load would be symetric, fairings would be tiny bit heavier.
No way to bring them together? You mean that it's impossible to control  force required to pull the cable? Or you say that using force in only one way it's not possible to gently stop momentum? Like for example on rocket falling from the sky? Or you claim that TOWs (thanks tyrred - I was lazy) weren't working because there is no cable which could easily withstand rocket exhaust?

It's always super easy to claim "no it's impossible". But that's rarely true. That would be too hard, or that would not be cost effective, or that could be dangerous/not reliable because of... that I could believe.

I'll try offer my criticism, and not just dismissal.  Although I would add that "dismissal", when it comes from many veteran sources pretty clued into real world experience with space hardware, is a good hint that an idea may not be great.   I like that this site because it has threads that allow some speculation.  Maybe this thread should be split, as the MOD has indicted he is considering.  I do think a thread based solely on what we "know", would be about 10 posts long, and boring.   Most of us here are probably of a technical/engineering background, and so we have PI's that either like to ruminate endlessly over such speculation, or we don't suffer fools, and dismiss things with little tact or feeling when we are so inclined.

So back to the topic of cables....

I don't think the cables seen in the SpaceX fairing test video from the Plum Brook facility indicate in any way that cables would work like this in a freefall/zero-g environment.   It's nice to imagine in our gravitationally conditioned minds that the fairings will magically come back together and reattach.  That's because our earth environment conditions our minds with lots of dampening and frictional forces.   

It's too easy to think of this problem like a household vacuum cord automatically winding itself back inside the appliance housing, but it just won't work like that.  Each pull of the cord/cable on attached fairing halves will accelerate the halves in the direction of the pull.   Unless the vector of that acceleration exactly moves the halves to a rendezvous, they will impact obliquely, & spin apart from each other from an in-elastic collision, and not rendezvous.   Furthermore, once they are accelerating towards each other, cables cant slow them down.   Ever try making compression forces with a string?  That means RCS and sensors, and you may as well eliminate the cables entirely.   I see a a big tangled mass of cable and fairing resulting after a few collisions together.
Title: Re: Fairing reuse
Post by: Stan-1967 on 04/09/2016 05:49 PM

And how to keep them connected? Well, I see on the video were they test separation mechanism that both parts are connected, so it seems possible. And in old days there were those rockets controlled by cables, so there are things which can survive and do the job.

It is not the cable that control the rocket, ( i.e TOW's) but electrical signals sent through the cable.  The cable is spooled out behind the rocket in a manner that tries to eliminate or reduce any drag or moments that affect the rockets guided flight path.   
Title: Re: Fairing reuse
Post by: Stan-1967 on 04/09/2016 05:57 PM

Thinking to something like this, very light.
For first part, reentry, managing the shock

http://forum.nasaspaceflight.com/index.php?topic=37727.msg1511754#msg1511754

I'd like it even more if it worked in a passive mode, vs. needing active control.  Something like this seems simple if it can keep the orientation stable.   So assuming this method keeps it stable and gets it into a landing zone, would you still need a parachute for soft landing?
Title: Re: Fairing reuse
Post by: cambrianera on 04/09/2016 06:08 PM

Thinking to something like this, very light.
For first part, reentry, managing the shock

http://forum.nasaspaceflight.com/index.php?topic=37727.msg1511754#msg1511754

I'd like it even more if it worked in a passive mode, vs. needing active control.  Something like this seems simple if it can keep the orientation stable.   So assuming this method keeps it stable and gets it into a landing zone, would you still need a parachute for soft landing?

No active control needed to keep it stable, basically  the shuttlecock principle.

Parachute still needed for softer landing.
Reorienting the half fairings concave first, drag increases two-three fold (plus parachute drag).
Title: Re: Fairing reuse
Post by: Stan-1967 on 04/09/2016 06:14 PM
Some "fairing blimp" calculations: feel free to skip.

Coming over from the airship thread, and reading upthread about the potential for having some kind of bladder on the inside of the fairing, I just wanted to do a back of the envelope on the possibility of converting each fairing half into a lighter-than-air craft before it reaches the ground.  Could inform potential Venus airship mission too.

Snip...

Not really sure of the weight/size requirements of the helium gas canister you'd need, but it seems to me this could be within the realms of workability, if you can have some kind of drogue chute that would keep the fairing somewhat oriented to protect the bladder material on the way down.

Thanks for doing those calcs.  I did some BOE that suggested the mass of the HE gas would be much less than the flexible bladder material.  My point in the bladder idea was not to make it "lighter than air" but to give it a shape that would be stable during a ballistic re-entry, and thereby aid in a smaller recovery zone.  Furthermore, if it could be landed with the bladder impacting the ocean as a type of "airbag", it would aid in preservation.

I think the adhesion of the bladder to the composite shell would be tricky, but doable.   Jim and others pointed out that problem.   It didn't seem overly complex to me, certainly not trivial.    It is very likely more simple methods would be tested long before the wilder ideas tossed around here.

1. nothing..just find it floating in the ocean
2. Some sort of controlled impact achieved with deployable control surfaces
3. Impact with drogue chute orienting the impact
4. Drogue chute plus bigger parachute orienting the impact
5. other ideas.
Title: Re: Fairing reuse
Post by: bstrong on 04/09/2016 06:29 PM
Today at the press debriefing Mr. E. Musk mentioned they are pursuing fairing reuse, because it costs several million dollars.
Wouldn't that be first official mention of fairing reuse?
Elon mentioned it in a tweet last year:

https://twitter.com/elonmusk/status/605460768516014080
Title: Re: Fairing reuse
Post by: Space Ghost 1962 on 04/09/2016 06:44 PM
Before you design a system, you must appreciate the environment of an existing system, what occurs in the life cycle of use, what qualities / requirements you have for the new system that the old one didn't have. E.g. aclear statement of the problem.

If I understand this wandering thread, what is desired is a jettisonable multipart fairing that largely works as the current one has done, but retains the integrity/registration/tensile qualities/compression/other of the fairing so that after its located/recovered, it can be economically remanufactured/reprocessed and qualified for reuse without refabrication?

The environment of this is to undergo payload/launch integration with US/LV, launch, ascent, staging, jettison ... as before. Then, either passively/actively negotiate the dissipation of extreme frictional heating and dynamic aeroloads in increasing atmospheric densities with decreasing velocities, until near terminal velocity and ocean impact.

And like the original system, you don't wish to greatly increase the mass penalty that robs from payload to orbit.

A lesser cost possibly is the drag of the system, so within the trades might be a larger effective diameter design with a hypothetical "fluffier" construction of some kind.

Also within the trades might be a design where the inside is much like the outside which already handles the ascent environment, with all the other requirements handled by stage or payload adapter or jettisonable (structure only reusable).

Next - prior experience. What allows past fairings to survive intact, and not others? When we compare a best case to an unused one, how has it been affected that makes the best case undesireable for reuse. What now do we have to preserve that we didn't before, and how do we instrument/test/prove such through consecutive flight, such that we converge on a useful solution.

All of this discussions would make this thread more focused and useful to address the topic.

Or is this just more jawing about random things that appeal or not?

add:
Approaches:
a) more durable version of the existing two part design (refinement)
b) reduced ballistic coefficient design with more, smaller components that each more easily survive to surface  (divide and conquer)
c) active structure that reconfigures post jettision to adapt to descent environment for better survival of structure (vehicle/glider?)
Title: Re: Fairing reuse
Post by: savuporo on 04/09/2016 06:53 PM
If I understand this wandering thread, what is desired is a jettisonable multipart fairing that largely works as the current one has done, but retains the integrity/registration/tensile qualities/compression/other of the fairing so that after its located/recovered, it can be economically remanufactured/reprocessed and qualified for reuse without refabrication?
Is symmetrical separation a must have ? Or can upper stage RCS deal with asymmetries ?

EDIT: also, what are the reasonable time limits for separation event ? A few seconds ? or tens of seconds ?
Title: Re: Fairing reuse
Post by: Space Ghost 1962 on 04/09/2016 07:13 PM
If I understand this wandering thread, what is desired is a jettisonable multipart fairing that largely works as the current one has done, but retains the integrity/registration/tensile qualities/compression/other of the fairing so that after its located/recovered, it can be economically remanufactured/reprocessed and qualified for reuse without refabrication?
Is symmetrical separation a must have ? Or can upper stage RCS deal with asymmetries ?


Symmetrical stress/loading is a must due to dynamic loads on launch. This dictates design and leads to fewer surprises in separation. Fabrication/test/qualification of symmetric parts simplifies proving such a design.

Titan had a triple gore design. There have been some unusual shrouds on certain payload in the past.

If you have any asymmetry/complexity, you risk recontact with the stage/payload. The more components/differences, the greater the risk.

That said, yes, such a design could possibly be made to work. The hard part would be proving that it always would work.

When you jettision, aeroloads are at a minimum by definition. The lower you jettison, the more mass you don't carry. Too low and the delicate payload is at risk.

add:
Quote

EDIT: also, what are the reasonable time limits for separation event ? A few seconds ? or tens of seconds ?
Sorry. Too quick.

We're talking seconds. Otherwise you are coasting, which for the ascent you are planning may not be feasible. And to be fair, coasts of a hundred seconds can occur, although likely not optimal.

Another item with asymmetry. Your payload and vehicle stack have to have at least a well known center of mass that you thrust through. If you partial jettison or asymmetric part jettison , your center of mass will shift, which you may or may not be able to compensate for in various ways - how do you avoid the cosine loss or attitude change?
Title: Re: Fairing reuse
Post by: savuporo on 04/09/2016 07:30 PM
Symmetrical stress/loading is a must due to dynamic loads on launch. This dictates design and leads to fewer surprises in separation. Fabrication/test/qualification of symmetric parts simplifies proving such a design.

Titan had a triple gore design. There have been some unusual shrouds on certain payload in the past.

If you have any asymmetry/complexity, you risk recontact with the stage/payload. The more components/differences, the greater the risk.

That said, yes, such a design could possibly be made to work. The hard part would be proving that it always would work.

When you jettision, aeroloads are at a minimum by definition. The lower you jettison, the more mass you don't carry. Too low and the delicate payload is at risk.
Well, any gadget you add beyond current system is always an added risk anyway. Question is, is the risk manageable and worth it.

For example, the two current fairing halves could be joined by servoed hinges on one side that fully opens one side before separation push, and then push it to one side. But thats a huuge asymmetry, not sure if this is remotely feasible.

The point would be to close clamshell again after separation to have the same aerodynamic shape reenter that went up. And then do trailing ballute, streamer or parachute or whatnot to survive the splash
Title: Re: Fairing reuse
Post by: Space Ghost 1962 on 04/09/2016 07:45 PM
Symmetrical stress/loading is a must due to dynamic loads on launch. This dictates design and leads to fewer surprises in separation. Fabrication/test/qualification of symmetric parts simplifies proving such a design.

Titan had a triple gore design. There have been some unusual shrouds on certain payload in the past.

If you have any asymmetry/complexity, you risk recontact with the stage/payload. The more components/differences, the greater the risk.

That said, yes, such a design could possibly be made to work. The hard part would be proving that it always would work.

When you jettision, aeroloads are at a minimum by definition. The lower you jettison, the more mass you don't carry. Too low and the delicate payload is at risk.
Well, any gadget you add beyond current system is always an added risk anyway. Question is, is the risk manageable and worth it.

Yes. Likely negligible gain just from the start. Have to have significant advantage. Like forming a reentry vehicle w/o much additional cost.

Quote
For example, the two current fairing halves could be joined by servoed hinges on one side that fully opens one side before separation push, and then push it to one side. But thats a huuge asymmetry, not sure if this is remotely feasible.

The point would be to close clamshell again after separation to have the same aerodynamic shape reenter that went up.

The asymmetries also affect the flight of the payload + US.

Here's a rude thought. You jettison with a hinge that opens, and the halves later "bounce" and relatch ;)

Now for the downsides of any of these. You have three vehicles that have to be axis symmetric/stable for flight - the original launch stack, the payload+US, and the reformed fairing/shroud.

And, to avoid recontact, you'd have to guarantee that the separation planes (two, not one)  could never be coincident - e.g. it "sticks" in one or both and the still combined fairing "tilts" into the payload.

Quote
And then do trailing ballute, streamer or parachute or whatnot to survive the splash

Separate issue entirely. Make it into a hypersonic glider.
Title: Re: Fairing reuse
Post by: cambrianera on 04/09/2016 07:50 PM

The point would be to close clamshell again after separation to have the same aerodynamic shape reenter that went up. And then do trailing ballute, streamer or parachute or whatnot to survive the splash

The shape that went up is not optimal for reentry.
It probably has a stable attitude, but the two half fairing have half mass/surface, therefore more chances to survive reentry (if stabilized).
Title: Re: Fairing reuse
Post by: Space Ghost 1962 on 04/09/2016 07:54 PM

The point would be to close clamshell again after separation to have the same aerodynamic shape reenter that went up. And then do trailing ballute, streamer or parachute or whatnot to survive the splash

The shape that went up is not optimal for reentry.
It probably has a stable attitude, but the two half fairing have half mass/surface, therefore more chances to survive reentry (if stabilized).

Yes, and the mass distribution will be all wrong as well for return/recovery "flight".

What you'd be after is some kind of "nested" (or recursive) design, where the offsets in one are balanced by the others. Not an easy design challenge.

The cost of jettison isn't cheap here. Remember, you could lose a mission in saving a buck.
Title: Re: Fairing reuse
Post by: Joel on 04/09/2016 08:51 PM
Is it out of the question to have the fairing separation event coincide with MECO and let the fairings attach to the first stage? From my understanding, MECO now happens at around 80 km (correct me if I'm wrong) which is not that far from space.

Doesn't the desire to eventually reuse the entire rocket suggest that the first stage needs to stage later in order to give more margin to the second stage?
Title: Re: Fairing reuse
Post by: cambrianera on 04/09/2016 09:05 PM
Is it out of the question to have the fairing separation event coincide with MECO and let the fairings attach to the first stage? From my understanding, MECO now happens at around 80 km (correct me if I'm wrong) which is not that far from space.

Doesn't the desire to eventually reuse the entire rocket suggest that the first stage needs to stage later in order to give more margin to the second stage?

Look at page 11 (all page, but specially this post http://forum.nasaspaceflight.com/index.php?topic=37727.msg1507081#msg1507081 )
Title: Re: Fairing reuse
Post by: savuporo on 04/09/2016 09:11 PM
The cost of jettison isn't cheap here. Remember, you could lose a mission in saving a buck.
Yeah but that somewhat of a weak argument for a rocket that already sprouted legs and grid fins. And yes, these are on first stage, but losing the payload with the first stage pays just as little as screwing up fairings or something else later.
Title: Re: Fairing reuse
Post by: robert_d on 04/10/2016 12:28 AM
So Here is a (just notional) picture based on the fact that E. Musk is really trying to find a way to reuse the fairings.
It assumes 1) that no possible set of equipment could be mounted within the fairing that would guarantee reuse. 2) No possible means will be found to rejoin the halves; and 3) the deceleration/reentry must include added energy and not just rely on a passive system. I understand the weight penalty such an idea entails. But in theory that could be offset a bit by firing the outer engines starting just before MECO and until fairing separation. Still to be determined would be final landing method. Dropping it directly into the ocean seems counter to the whole idea of reuse.
Title: Re: Fairing reuse
Post by: meekGee on 04/10/2016 12:33 AM
There's another idea that was batted around a long time ago.

Have fairing retract, as a whole cylinder, onto the first stage, and return with it.

What's left around the pilot is a light cover that's sufficient to protect the payload against the residual atmosphere at 100 km.

(I believe that this damage is from the speed of the flow, but that the actual force on the payload is very low)

The clear negative is that you need to separate this secondary cover as well.

The positives are that A) you carry the heavy payload to a lower altitude, and B) that they come back with the first stage and so don't need an additional recovery mechanisms, helicopters, etc.

EDIT:  To clarify - this is just blue sky thinking.   The plan right now is clearly to parachute the two individual halves, and then recover mid-air.
Title: Re: Fairing reuse
Post by: robert_d on 04/10/2016 01:04 AM
Just had another thought. Make second stage 5 meters like the original fairing but then mount the payload BEHIND the second stage propellant tanks. Interstage would then be just really long.  Engine bell would swing away on a hing just before the payload deploys behind the tanks. How's THAT for the crazy meter?
Title: Re: Fairing reuse
Post by: CJ on 04/10/2016 01:07 AM
I'll take a stab at reading the tea leaves here, based on what's known plus some wild theorizing on my part as to what SpaceX might have in mind.

Okay, what's known? I'm taking it as a given that they want to recover and reuse fairings. I'm also taking it as a given that one of the fairing halfs had a cold gas thruster of some sort on SES9.

So here's my wild guesswork; the eventual plan is to, via very tiny clod gas thrusters, stabilize the fairing halfs so that they are enter outside-first (sort of like a boat floating) relative to the velocity vector. To damp out oscillation and impart a little stability, spin them at a few RPM (with the rotational axis aligned with the velocity vector). Based on what we've seen washed up, that might (I'm guessing) get them past the reentry.

After reentry, deploy a small drogue chute on a strong line. Assuming the fairings can't be immersed in salt water (?) this line and drogue could be snagged by a helicopter with the correct gear.

It would be far easier if the fairings could be immersed in salt water, assuming their terminal velocity (perhaps aided by a small drogue) would make water impact survivable, but I don't know whether that's feasible.

For location and tracking in either case, a small GPS-based transponder could be used. 

 
Title: Re: Fairing reuse
Post by: Radical_Ignorant on 04/10/2016 07:22 AM

And how to keep them connected? Well, I see on the video were they test separation mechanism that both parts are connected, so it seems possible. And in old days there were those rockets controlled by cables, so there are things which can survive and do the job.


not true on either point.  The cables would put loads on the fairings and there is no way to bring them together in a controlled matter without them slamming together.

Which rockets were controlled by cables?

Of course that they would put loads, and so? This load would be symetric, fairings would be tiny bit heavier.
No way to bring them together? You mean that it's impossible to control  force required to pull the cable? Or you say that using force in only one way it's not possible to gently stop momentum? Like for example on rocket falling from the sky? Or you claim that TOWs (thanks tyrred - I was lazy) weren't working because there is no cable which could easily withstand rocket exhaust?

It's always super easy to claim "no it's impossible". But that's rarely true. That would be too hard, or that would not be cost effective, or that could be dangerous/not reliable because of... that I could believe.


How about "it's simply unnecessary."

Could you then please explain me what is necessary? I could believe that all is really required it's to reduce speed of impact with water. Pieces found are already quite large, so it would be believable.
Can you then help me and explain what for are those tests with controlling them? What could it help?
Title: Re: Fairing reuse
Post by: Radical_Ignorant on 04/10/2016 07:54 AM
{....}

I'll try offer my criticism, and not just dismissal.  Although I would add that "dismissal", when it comes from many veteran sources pretty clued into real world experience with space hardware, is a good hint that an idea may not be great.   
{....}
This is wrong. I'm not disrespecting his opinion, I'm not even saying he is wrong and I'm right. All I was saying is that he provided nothing more than an opinion. And if something is valid because senior engineer said that - that is argument from person, from authority, not from fact. It's no educational value or no value at all. It's more an order than an answer "I'm senior here, be quiet and listen". And there is infinite amount of examples where senior (old, experienced) space guys were wrong :p

Sure I understand that lot of you folks are tired of our ignorance and dumb ideas. But then patience and politeness are things thanks to which we could admire your knowledge and learn from this forum even more.

So back to the topic of cables....

I don't think the cables seen in the SpaceX fairing test video from the Plum Brook facility indicate in any way that cables would work like this in a freefall/zero-g environment.   It's nice to imagine in our gravitationally conditioned minds {....}
It's accelerating, not free falling, so you are wrong here. However force is probably not 1g so it would behave differently, but I don't know why much differently.

It's too easy to think of this problem like a household vacuum cord automatically winding itself back inside the appliance housing, but it just won't work like that.  Each pull of the cord/cable on attached fairing halves will accelerate the halves in the direction of the pull.   Unless the vector of that acceleration exactly moves the halves to a rendezvous, they will impact obliquely, & spin apart from each other from an in-elastic collision, and not rendezvous.   Furthermore, once they are accelerating towards each other, cables cant slow them down.   Ever try making compression forces with a string?  That means RCS and sensors, and you may as well eliminate the cables entirely.   I see a a big tangled mass of cable and fairing resulting after a few collisions together.

1) They won't spin apart because they will be hold together by the very cable we talk about. That's the reason why IMO it could make sense - there I s no docking mechanism.

2) "Each pull will..." Sure it will. So you have 8 points to attach force. Quite a control system. It's not complicated to simulate it in software. Of course much harder to make it working in this simulation. But I believe it's software problem how to bring them back together gently.

3) "Can't slow them down." That's why you do it gently. Like shuttle landing. Once it was over airfield you could not move it up and try again. I don't see it as no go.

Title: Re: Fairing reuse
Post by: Ohsin on 04/10/2016 11:08 AM
So at the moment they are looking to recover one half if I am right. But lets say in future after all experience gained they are recovering both halves, if recovery of one half goes wonky would that make other piece useless? Or these halves are designed to be swap-able?
Title: Re: Fairing reuse
Post by: cambrianera on 04/10/2016 12:11 PM
So at the moment they are looking to recover one half if I am right. But lets say in future after all experience gained they are recovering both halves, if recovery of one half goes wonky would that make other piece useless? Or these halves are designed to be swap-able?
Halves are manufactured separately (not single piece fairing cut in half) on computer controlled machinery.
Likely swappable.
Title: Re: Fairing reuse
Post by: Jim on 04/10/2016 12:23 PM
It's always super easy to claim "no it's impossible". But that's rarely true. That would be too hard, or that would not be cost effective, or that could be dangerous/not reliable because of... that I could believe.

"too hard, or that would not be cost effective, or that could be dangerous/not reliable because of." equates to "it's impossible"
Title: Re: Fairing reuse
Post by: Jim on 04/10/2016 12:29 PM

2) "Each pull will..." Sure it will. So you have 8 points to attach force. Quite a control system. It's not complicated to simulate it in software. Of course much harder to make it working in this simulation. But I believe it's software problem how to bring them back together gently.

3) "Can't slow them down." That's why you do it gently. Like shuttle landing. Once it was over airfield you could not move it up and try again. I don't see it as no go.


No, it is not a software problem. Cables are inadequate in that they can not provide 6 DOF control, since the only other anchor is the other fairing..   They will not prevent the fairing from twisting or hitting each other. There still are aero loads at separation.
Title: Re: Fairing reuse
Post by: Jim on 04/10/2016 12:32 PM
 
Or you claim that TOWs (thanks tyrred - I was lazy) weren't working because there is no cable which could easily withstand rocket exhaust?

Not relevant example.  Those cables weren't hundreds of miles long.  Also, the two TOW exhausts are angled way from the center line
Title: Re: Fairing reuse
Post by: Kaputnik on 04/10/2016 12:48 PM
You know, if it would be possible to hinge the damn thing, why not simply hinge it along one long edge? Then it could open along that edge and tumble away still connected.
If you push a long edge hinged fairing over the other long edge, you get an inward movement of the hinge.
You can add a reaction beam to keep the hinge clear from the payload, but this would increase the mass of the fairing.
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=37727.0;attach=1106960)


Is it just me or does that looks rather Rogallo-esque? Hmmm...
Title: Re: Fairing reuse
Post by: llanitedave on 04/10/2016 03:23 PM

And how to keep them connected? Well, I see on the video were they test separation mechanism that both parts are connected, so it seems possible. And in old days there were those rockets controlled by cables, so there are things which can survive and do the job.


not true on either point.  The cables would put loads on the fairings and there is no way to bring them together in a controlled matter without them slamming together.

Which rockets were controlled by cables?

Of course that they would put loads, and so? This load would be symetric, fairings would be tiny bit heavier.
No way to bring them together? You mean that it's impossible to control  force required to pull the cable? Or you say that using force in only one way it's not possible to gently stop momentum? Like for example on rocket falling from the sky? Or you claim that TOWs (thanks tyrred - I was lazy) weren't working because there is no cable which could easily withstand rocket exhaust?

It's always super easy to claim "no it's impossible". But that's rarely true. That would be too hard, or that would not be cost effective, or that could be dangerous/not reliable because of... that I could believe.


How about "it's simply unnecessary."

Could you then please explain me what is necessary? I could believe that all is really required it's to reduce speed of impact with water. Pieces found are already quite large, so it would be believable.
Can you then help me and explain what for are those tests with controlling them? What could it help?


I've suggested a small parachute.  That and maybe a couple of small aerodynamic surfaces to add a bit of stability.  Don't see the need for much else.
Title: Re: Fairing reuse
Post by: Radical_Ignorant on 04/10/2016 06:00 PM

2) "Each pull will..." Sure it will. So you have 8 points to attach force. Quite a control system. It's not complicated to simulate it in software. Of course much harder to make it working in this simulation. But I believe it's software problem how to bring them back together gently.

3) "Can't slow them down." That's why you do it gently. Like shuttle landing. Once it was over airfield you could not move it up and try again. I don't see it as no go.


No, it is not a software problem. Cables are inadequate in that they can not provide 6 DOF control, since the only other anchor is the other fairing..   They will not prevent the fairing from twisting or hitting each other. There still are aero loads at separation.

Since there are four points of attachments on each fairing half it's easy to control twisting. You know how long is each cable. As well as it's easy to measure pressure on the cable. If one is longer that means it should be pulled little bit faster than other ones.

No 6DOF control? Why you need that?

I doubt now we talk about the same they thing? Why should they prevent fairing halves from hitting each other? It's all about hitting each other in controlled manner to reconnect and make shape which is safe in atmospheric heat and can be easily make floatable.

Sorry for lacking animation skill.

I see there two problems, which no one mentioned.
1) cables can touch payload or rocket in initial phase
2) it makes no difference really - it's all just about making it hit water little slower, atmospheric part makes no harm for them in current state or half fairing are good and stable enough lifting body and it's just enough to attach small parachutes to them and stabilize their rotation for a moment of launching it?
Title: Re: Fairing reuse
Post by: S.Paulissen on 04/10/2016 08:15 PM
It just seems the simplest solution would be to put a 'light' TPS on the outer surface of the fairing and stabilize the reentry orientation with an inflatable drag augmentation device (al la NASA's low density supersonic decelerator)  and eat the mass penalty by throwing performance at it. 

I seriously doubt they'll go much further down the fairing recovery road until they have enough excess performance to make the more error resistant plan work (i.e. keep sep nearly identical to current practice, then add steps later to reduce risk).
Title: Re: Fairing reuse
Post by: Jim on 04/11/2016 01:58 PM
Since there are four points of attachments on each fairing half it's easy to control twisting. You know how long is each cable. As well as it's easy to measure pressure on the cable. If one is longer that means it should be pulled little bit faster than other ones.

No 6DOF control? Why you need that?

I doubt now we talk about the same they thing? Why should they prevent fairing halves from hitting each other? It's all about hitting each other in controlled manner to reconnect and make shape which is safe in atmospheric heat and can be easily make floatable.



there is no "hitting" of the fairing halves.  they would get damaged.  Fairing mate is a slow and controlled motion.

What four attach points?

6DOF is needed because the cables are going to be tens of feet long and the fairing halves are going to be subject to aero and plume loads which will give them different rotation and translation rates.  They are not going to remain "collinear"  . The cables will be long enough to get twisted or have the fairings halves contact each other in weird attitudes


Title: Re: Fairing reuse
Post by: JamesH65 on 04/11/2016 02:19 PM
I'm still not sure why people want to bring the fairing back together. Why not just attempt to land each half individually. It's going to act more like a leaf when still in halves, rather than a bullet when recombined, which should mean an overall less stressful reentry.
Title: Re: Fairing reuse
Post by: Remes on 04/11/2016 10:46 PM
I found the comment in the after launch press conference from EM interesting (at 33:33): Each of the fairing halfs cost several millions.

Playing around with numbers: if each fairing half is 2mio (lower boundary), then the complete fairing is 4 mio. If I take 4mio per engine as an absolute upper boundary (then 10 engines would be 40mio, fairing 4 million and leaving 16mio for everything else including launch, testing and perhaps profit), then one fairing would equal the cost of one engine. Which seems somehow odd, given the complexity of an engine. And I would rather guess an engine is less then 4mio (because 16mio for everything else is not too much).
Title: Re: Fairing reuse
Post by: envy887 on 04/11/2016 11:18 PM
For a low temperature, low stress re-entry it helps to increase area, reduce mass, and increase drag coefficient.

Orienting halves individually with the concave side forward helps with all those.
Title: Re: Fairing reuse
Post by: georgegassaway on 04/11/2016 11:34 PM

BALLUTE
Title: Re: Fairing reuse
Post by: hrissan on 04/12/2016 04:17 PM
Each half should land independently, that's clear.

Here is how: each half has large parts of each on hinges, so it splits open, obtaining the shape of maple seed, then splashes down into water on autorotation!!! :):):)
Title: Re: Fairing reuse
Post by: Doesitfloat on 04/12/2016 04:48 PM

BALLUTE

Don't be silly that could be lightweight and practical. :)

Then when they are lower... just catch em

https://www.youtube.com/watch?v=XxFZ-VStApo
Title: Re: Fairing reuse
Post by: wannamoonbase on 04/12/2016 05:59 PM
I found the comment in the after launch press conference from EM interesting (at 33:33): Each of the fairing halfs cost several millions.

Playing around with numbers: if each fairing half is 2mio (lower boundary), then the complete fairing is 4 mio. If I take 4mio per engine as an absolute upper boundary (then 10 engines would be 40mio, fairing 4 million and leaving 16mio for everything else including launch, testing and perhaps profit), then one fairing would equal the cost of one engine. Which seems somehow odd, given the complexity of an engine. And I would rather guess an engine is less then 4mio (because 16mio for everything else is not too much).

The engines are a volume production product and could be getting cheaper with each one produced.  Depending on material costs.  SpaceX should be getting smarter and more efficient as they continue to crank out these engines, plus development costs get spread out more with each one made.

Fairings are a large structure, lower volume, hard to make, hard to handle, hard to ship. 

I can see the fairings as being more expensive than a single Merlin 1D.

Re-use will put additional pressure on competitors.
Title: Re: Fairing reuse
Post by: rds100 on 04/12/2016 06:15 PM

They should just learn how to build these cheaper, say some sort of 3D printing. Nowadays even large structures can be 3D printed.

Title: Re: Fairing reuse
Post by: Kaputnik on 04/12/2016 07:18 PM

They should just learn how to build these cheaper, say some sort of 3D printing. Nowadays even large structures can be 3D printed.



Composite materials get their strength from the use of (long) directional fibres.
3D printing isn't the answer to everything...
Title: Re: Fairing reuse
Post by: iamlucky13 on 04/12/2016 08:41 PM
3-D printing is massively over-hyped in the pop-science world. It has a growing, but still small place in the real engineering world, primarily for relatively complex shapes with low tolerances made in low volumes of single materials. 3-D printing as the most people recognize it is not suited for producing rocket fairings.

That said, there is a 3-D printing-like technology for carbon fiber (actually, a couple, but the types that extrude short-fiber+binder mixes like a regular 3-D printer are far from optimal strength or production rate wise): The NASA ISAAC robot definitely can do carbon fiber structure layup on this scale, when combined with rotating tooling. It's a variation of the same technology that produces the 787 fuselage sections. A larger custom gantry machine could do it with static tooling. SpaceX is well aware of this technology.

That only produces the uncured laminate, however. A single step would have been automated. That reduces the labor cost for that step somewhat, but whether it is enough to justify the up-front cost of the robot and more complex tooling is for SpaceX to figure out based on required production rates.

It still requires curing, trimming, stiffener and bracket installation, acoustic panel installation, and systems installation, including the latches and separation pushers, which themselves are relatively expensive parts.

I might as well also point out that SpaceX said a year or two ago that as they transition to higher production rates, they are doing work to streamline production throughout the factory, and part of the result of that should be lower production costs, but the fairings will remain a relatively significant cost that re-use could potentially lessen.
Title: Re: Fairing reuse
Post by: Robotbeat on 04/15/2016 09:28 PM

They should just learn how to build these cheaper, say some sort of 3D printing. Nowadays even large structures can be 3D printed.



Composite materials get their strength from the use of (long) directional fibres.
3D printing isn't the answer to everything...
The relevant tech here would be an automated fiber layup machine like is used for airplanes. It's still technically "Additive Manufacturing," so it's a kind of 3d printing except it uses a mandrel.

Still, SpaceX is better off trying reuse. They need to get good at this sort of thing anyway.

EDIT: Yes, the ISAAC machine. But these kind of machines are actually much better understood and more effectively utilized in industry than at NASA, to be absolutely honest. ISAAC is kind of a "me too!" sort of development, not anything ground-breaking (except in the literal sense since they need to reinforce the floor).
Title: Re: Fairing reuse
Post by: Space Ghost 1962 on 04/15/2016 10:46 PM

They should just learn how to build these cheaper, say some sort of 3D printing. Nowadays even large structures can be 3D printed.



Composite materials get their strength from the use of (long) directional fibres.
3D printing isn't the answer to everything...

6 months ago I was listening to a presentation on 3D printing composite materials for space/LV application, where they were laying down fibers with long range orientation/registration/no kinks/no twist. (They are thinking about forming them like "pre-stressed" concrete beams, with a programmed distribution of fiber characteristics so as to make structural parts that are otherwise impossible to fabricate any other way ...
Title: Re: Fairing reuse
Post by: cambrianera on 04/18/2016 07:47 PM
This is how fairing flaps can behave/deploy.
Obviously really simplified  ;)
Title: Re: Fairing reuse
Post by: sanman on 04/19/2016 06:04 AM
This is how the professionals do it - the clamshell way:

https://www.youtube.com/watch?v=4FTB8TgvgUk

(http://www.stopelonmusk.org/tumblr_m90ka7Zr021rby5xwo1_500.jpg)
Title: Re: Fairing reuse
Post by: Blackjax on 04/23/2016 06:36 PM

In this post
https://forum.nasaspaceflight.com/index.php?topic=39181.msg1521556#msg1521556

...an idea gets laid out that the F9 might be relegated to more mid-sized payloads well inside its performance envelope once the FH is flying regularly and that this might leave reserve capacity for RTLS.  If you take this idea and run with it on the fairing front, what you might end up with is an improved mass budget for a redesigned & reusable fairing flying on a sandbagged F9 or a FH (which is otherwise overkill for most payloads that the market might produce in the foreseeable future).  Consider also that a redesigned fairing does not need to be optimized for shipping considerations the same way that an expendable would, because shipping logistics complexity and cost are amortized over many flights and you are shipping much fewer of them.

I have often wondered if the point of the FH isn't to loft big payloads, but to enable a combined F9/FH reusable fleet to shift mass margins across the existing market for payloads to maximize reusability and "aircraft like operations".
Title: Re: Fairing reuse
Post by: rds100 on 04/23/2016 07:19 PM

 Consider also that a redesigned fairing does not need to be optimized for shipping considerations the same way that an expendable would, because shipping logistics complexity and cost are amortized over many flights and you are shipping much fewer of them.


Am imissing something here? A reused fairing would need to be shipped many times, since it wouldn't return to the launch site, it would end somewhere in the ocean. Then it need to be retrieved, brought to land, transported by road, etc.


Title: Re: Fairing reuse
Post by: launchwatcher on 04/23/2016 07:29 PM

 Consider also that a redesigned fairing does not need to be optimized for shipping considerations the same way that an expendable would, because shipping logistics complexity and cost are amortized over many flights and you are shipping much fewer of them.


Am imissing something here? A reused fairing would need to be shipped many times, since it wouldn't return to the launch site, it would end somewhere in the ocean. Then it need to be retrieved, brought to land, transported by road, etc.
Short-distance road transport of oversized items from Port Canaveral to various launch pads at the Cape is clearly a solved problem.   



Title: Re: Fairing reuse
Post by: iamlucky13 on 04/27/2016 07:06 PM
The relevant tech here would be an automated fiber layup machine like is used for airplanes. It's still technically "Additive Manufacturing," so it's a kind of 3d printing except it uses a mandrel.

Still, SpaceX is better off trying reuse. They need to get good at this sort of thing anyway.

EDIT: Yes, the ISAAC machine. But these kind of machines are actually much better understood and more effectively utilized in industry than at NASA, to be absolutely honest. ISAAC is kind of a "me too!" sort of development, not anything ground-breaking (except in the literal sense since they need to reinforce the floor).

There might be a bit of "me-too" involved in the decision making to purchase ISAAC, but the stated intent is to allow NASA to prototype structures more easily.

It's somewhat surprising how much work is still going on within the aerospace industry just characterizing the performance of different layup patterns. I have a friend who recently left his aerospace engineering job in part because he was looking for more variety than continuously iterating small variations in fiber orientation, ply thickness, etc, analyzing their strength in various load cases, then sending along the better patterns to the test engineers to fabricate samples of to test and compare to the analysis. He spent several years doing this.

I presume NASA tends to work with different fibers and resins than the aircraft industry, and certainly different part shapes, so they may well have their own justification for on-site prototyping, such as for subscale or truncated fairing and interstage pieces or stiffeners for SLS. Fairings or interstages have large axial loads, but less significant pressure and bending loads. Aircraft fuselages have large pressure and bending loads, but relatively little axial loading, so what is optimal for aircraft is not what is optimal for rockets. I suppose from NASA's point of view, they'll pay for that optimization one way or another: either their suppliers figure it out and factor the development costs into what they charge, or NASA figures it out and shares the data with suppliers and the whole industry benefits.


6 months ago I was listening to a presentation on 3D printing composite materials for space/LV application, where they were laying down fibers with long range orientation/registration/no kinks/no twist. (They are thinking about forming them like "pre-stressed" concrete beams, with a programmed distribution of fiber characteristics so as to make structural parts that are otherwise impossible to fabricate any other way ...

That's automated fiber placement (AFP), like ISAAC. I believe it, or at least automated tape laying (ATL), started to be used for medium-sized aircraft structures in the 90's. NASA is not the only spaceflight organization starting to look at AFP.

It is possible to fabricate large parts in other ways. Hand layup is still an option, but very tedious. Most hand layup is done with woven or stitched multi-directional fiber cloth. Larger pieces can be put down that way, which helps with production efficiency, but you have less ability to play with the fiber direction since the material you're working with has been woven or stitched with fibers in specific orientations relative to each other. Most machine layup is done with ribbon-like "tows", frequently 1/4 to 1/2 inch wide, or for low curvature parts, sometimes with "tape" 6+ inches wide. Each fiber can have its orientation chosen more or less how the engineer wants within the final structure.

As a result of how each company evaluates those trade offs, I know of different aircraft that have similar parts made in different ways (AFP vs. ATL vs. hand layup of multi-directional fibers). So although SpaceX has the option of investing in fiber placement for their fairings, don't assume that it's necessarily the best choice for what they're doing.
Title: Re: Fairing reuse
Post by: mme on 05/16/2016 04:31 AM
https://twitter.com/elonmusk/status/732042627445460992 (https://twitter.com/elonmusk/status/732042627445460992)

Quote
Raket_Mand @bittdk
@elonmusk how did the recovery of the fairings go?

Quote
Elon Musk ‏@elonmusk  1h1 hour ago
@bittdk Better. Not there yet, but a solution is likely.
Title: Re: Fairing reuse
Post by: sevenperforce on 05/16/2016 12:46 PM
https://twitter.com/elonmusk/status/732042627445460992 (https://twitter.com/elonmusk/status/732042627445460992)

Quote
Raket_Mand @bittdk
@elonmusk how did the recovery of the fairings go?

Quote
Elon Musk ‏@elonmusk  1h1 hour ago
@bittdk Better. Not there yet, but a solution is likely.
Good to see an update on this.

With the current ballistic re-entry, what are the estimated damage ratios? Like, 40% re-entry and 60% ocean impact? Or flipped?
Title: Re: Fairing reuse
Post by: cscott on 05/16/2016 04:20 PM
We haven't seen any recovered fairing pieces come back on go searcher yet.  So I'd say 100% re-entry right now.  The re-entry damage is sufficient to destroy any chance of recovering locatable pieces at least.
Title: Re: Fairing reuse
Post by: RDMM2081 on 05/16/2016 04:39 PM
Sorry if this is too elementary of a question or if I missed it being asked or answered previously, but is there any indication if the fairing pieces have any GPS or beacon tracking capabilities yet?  This would assume that the recovery boat could at least check in the right location to find any pieces that did make it to the surface. 

edit: removed GPS, apparently off-the-shelf models "self-destruct" upon nearing anything resembling ICBM speeds/altitudes, also removed completely redundant link to old article after re-reading the thread.

Still seems to me like finding any pieces of currently designed fairing is the most informative path forward to inform any more advanced recovery options in the future after seeing what the pieces look like, just need to find some.
Title: Re: Fairing reuse
Post by: kevin-rf on 05/16/2016 07:53 PM
edit: removed GPS, apparently off-the-shelf models "self-destruct" upon nearing anything resembling ICBM speeds/altitudes, also removed completely redundant link to old article after re-reading the thread.

Self destruct??? More like become civilian off the shelf devices become inaccurate because they can not properly process the timing signals and arrive at the correct result. Once they slow down, like hitting terminal velocity or bobbing in the ocean, accuracy should be restored.
Title: Re: Fairing reuse
Post by: launchwatcher on 05/16/2016 08:44 PM
edit: removed GPS, apparently off-the-shelf models "self-destruct" upon nearing anything resembling ICBM speeds/altitudes, also removed completely redundant link to old article after re-reading the thread.

Self destruct??? More like become civilian off the shelf devices become inaccurate because they can not properly process the timing signals and arrive at the correct result. Once they slow down, like hitting terminal velocity or bobbing in the ocean, accuracy should be restored.
Commodity GPS receivers have hard-coded speed and altitude limits and will shut down if they see they're moving too fast and/or too high.   

See, for instance, http://support.spectracom.com/articles/FAQ/Why-are-there-altitude-and-velocity-limits-for-GPS-equipment

Receivers without the limits are subject to export controls to ensure they don't end up guiding ICBM's.
Title: Re: Fairing reuse
Post by: manoweb on 05/16/2016 09:41 PM
I believe SpaceX might have the permissions in place to use GPS units that are enabled to work in a "rocket" scenario.
Title: Re: Fairing reuse
Post by: RDMM2081 on 05/16/2016 09:54 PM
edit: removed GPS, apparently off-the-shelf models "self-destruct" upon nearing anything resembling ICBM speeds/altitudes, also removed completely redundant link to old article after re-reading the thread.

Self destruct??? More like become civilian off the shelf devices become inaccurate because they can not properly process the timing signals and arrive at the correct result. Once they slow down, like hitting terminal velocity or bobbing in the ocean, accuracy should be restored.
Commodity GPS receivers have hard-coded speed and altitude limits and will shut down if they see they're moving too fast and/or too high.   

See, for instance, http://support.spectracom.com/articles/FAQ/Why-are-there-altitude-and-velocity-limits-for-GPS-equipment

Receivers without the limits are subject to export controls to ensure they don't end up guiding ICBM's.

Yeah, shut down is probably a better way to phrase it than "self-destruct", and that is the "feature" I was referring to, sorry if that was overly dramatic...  Also, SpaceX probably does have access to the "military grade" receivers so GPS might still be an option, but definitely not as easy as gluing a Garmin inside the fairing and seeing what happens.  Some sort of transmitter beacon seems much more likely to me.  Assuming they are doing any tracking at all, but otherwise how would they find any fairing which did make it to the surface, either intact, or in large enough pieces to be found?
Title: Re: Fairing reuse
Post by: kevin-rf on 05/17/2016 01:28 AM
Uuuuum... Radar, the range does track these things and they do know where they generally splashed. Add to that for a fairing to survive it's final speed will be slow enough that civilian gps systems will work. Impact will not be at mach 10.

Easiest solution, stick an iridium phone in each half and have it call home as soon as it splashed down. The phone will have gps. I don't know how fancy iridium phones are, but maybe they can write an app. Provide it a Twitter feed. Tweets like whoa, that was intense, and a shark just swam by. They did get a go pro back from one of the fairings.
Title: Re: Fairing reuse
Post by: kevin-rf on 05/17/2016 01:32 AM
Also, a spaceX fairing has already washed ashore. It had a go pro in it, and they did post the video.
Title: Re: Fairing reuse
Post by: meekGee on 05/17/2016 08:55 AM


Easiest solution, stick an iridium phone in each half and have it call home as soon as it splashed down. The phone will have gps.

Yeah, but who will make the call?

Aha! Trained dolphins!  On both ends of the call of course!  I can see it now!

Title: Re: Fairing reuse
Post by: JamesH65 on 05/17/2016 10:54 AM
edit: removed GPS, apparently off-the-shelf models "self-destruct" upon nearing anything resembling ICBM speeds/altitudes, also removed completely redundant link to old article after re-reading the thread.

Self destruct??? More like become civilian off the shelf devices become inaccurate because they can not properly process the timing signals and arrive at the correct result. Once they slow down, like hitting terminal velocity or bobbing in the ocean, accuracy should be restored.
Commodity GPS receivers have hard-coded speed and altitude limits and will shut down if they see they're moving too fast and/or too high.   

See, for instance, http://support.spectracom.com/articles/FAQ/Why-are-there-altitude-and-velocity-limits-for-GPS-equipment

Receivers without the limits are subject to export controls to ensure they don't end up guiding ICBM's.

Yeah, shut down is probably a better way to phrase it than "self-destruct", and that is the "feature" I was referring to, sorry if that was overly dramatic...  Also, SpaceX probably does have access to the "military grade" receivers so GPS might still be an option, but definitely not as easy as gluing a Garmin inside the fairing and seeing what happens.  Some sort of transmitter beacon seems much more likely to me.  Assuming they are doing any tracking at all, but otherwise how would they find any fairing which did make it to the surface, either intact, or in large enough pieces to be found?

Even if they had no access to 'military' GPS (ie usable at all speeds and altitudes) hardware, they could always make their own high accuracy system. Already been done by a guy I used to work with.

http://www.aholme.co.uk/GPS/Main.htm

Title: Re: Fairing reuse
Post by: Jim on 05/17/2016 01:48 PM
but otherwise how would they find any fairing which did make it to the surface, either intact, or in large enough pieces to be found?

They see it floating.  If it sinks they don't care about it.
Title: Re: Fairing reuse
Post by: Nomadd on 05/17/2016 02:47 PM
Uuuuum... Radar, the range does track these things and they do know where they generally splashed. Add to that for a fairing to survive it's final speed will be slow enough that civilian gps systems will work. Impact will not be at mach 10.

Easiest solution, stick an iridium phone in each half and have it call home as soon as it splashed down. The phone will have gps.
No need for even that much. If it's OK with the Coast Guard, they can just stick an off the shelf EPIRB in them with some sort of custom trigger.
Title: Re: Fairing reuse
Post by: kevin-rf on 05/17/2016 03:11 PM
No need for even that much. If it's OK with the Coast Guard, they can just stick an off the shelf EPIRB in them with some sort of custom trigger.
Raised eyebrows. Like I said, several off the shelf tracking solutions exists. Miss using EPIRB is not one of them.

The simplest and most foolproof are devices that communicate with existing LEO networks (Orbcomm, Iridium) and just say here I am, over here... Besides, both Orbcomm and Iridium should have very good relations with SpaceX, maybe they will give them a discount.

Heck, Iridium is about to roll out an aircraft tracking service.

No need to invent anything, and the fairings are already coming down intact enough that people do find them from time to time.
Title: Re: Fairing reuse
Post by: kevin-rf on 05/17/2016 03:17 PM
Off the shelf: https://www.iridium.com/products/details/spidertracks-satellite-tracking

Quote
Spidertracks Satellite Tracking

Spidertracks is more than just a tracking system: as well as knowing exactly where people and valuable assets are at any moment in time, it can also tell you how they are. If something goes wrong, and the website loses contact with the spider device, the system will automatically send text and email alerts to the right people, including rescue services, within minutes of the accident occurring. Because the alert is generated by the system, it doesn’t rely on the device surviving an accident, so it will always be sent, enabling rescue services to locate the site quickly based on the last transmitted position. With Spidertracks, no one needs to be lost at sea, on land, or in the air again.

It combines a portable tracking unit, the Spider, with a web-based client interface, enabling users to access their flight following and tracking details from anywhere at any time via the internet. Powered by a 10 V – 32 V power source, it has no external antenna and can be moved between aircraft or vehicles, so it doesn’t require expensive installation or certification. Partnered with Iridium, it offers global coverage.

Spidertracks also offers simple two-way global communication. Customers can send and receive texts with a compatible phone from anywhere on earth, via Iridium, through the Spidertracks website—ideal for anyone who needs to communicate from a remote region without GSM/cellphone coverage.

The unit is portable, with the tracks accessed from any internet connected device, and it is AFF compliant, offering a cost-effective, simple and reliable tracking-based safety system for anyone working or traveling in remote locations or risky situations.

Problem solved. Though, adding a smoke generator and disco lights would be a nice touch.
Title: Re: Fairing reuse
Post by: RDMM2081 on 05/17/2016 03:44 PM
but otherwise how would they find any fairing which did make it to the surface, either intact, or in large enough pieces to be found?

They see it floating.  If it sinks they don't care about it.
Uuuuum... Radar, the range does track these things and they do know where they generally splashed. Add to that for a fairing to survive it's final speed will be slow enough that civilian gps systems will work. Impact will not be at mach 10.

Easiest solution, stick an iridium phone in each half and have it call home as soon as it splashed down. The phone will have gps. I don't know how fancy iridium phones are, but maybe they can write an app. Provide it a Twitter feed. Tweets like whoa, that was intense, and a shark just swam by. They did get a go pro back from one of the fairings.

If all the following are true, then what has stopped them before?

1)  SpaceX are and have been interested in fairing recovery
2)  The fairing's are trackable via range radar
3)  One landed intact enough to float to shore

Was the Bahamas fairing making it to shore unclaimed a case where they were simply not interested in tracking it down and attempting recovery?  Or is it harder to find a fairing based only off a "last known position" obtained via range radar and then some hours later when they arrive at the spot, it's not there?  Oceans are big.

I think if the fairings/pieces are making it to the water, SpaceX needs a slightly better method for tracking them down and finding them.  GPS seems doable, but a beacon also seems like a good way to zero in on a spot if you have a ballpark area to start looking (range radar tracking will get you there apparently). 

The other opinion of mine I will toss out there is that they are, can, should, and will continue to experiment with RSC thrusters and start adding deployable control surfaces to help the fairings make it to the surface, in order to be tracked and then recovered.  I am not a fan of any of the "clamshell" or "reassembly" methods described upthread.  I do like the direction of the inflatable recovery mods, either ballooning, ballistic spinup, or just a flotation assist to keep the pieces from sinking.
Title: Re: Fairing reuse
Post by: cscott on 05/17/2016 04:25 PM
Go Searcher, which we believe to be the fairing recovery ship, has only gone out on the last few (three?) missions.  The washed-ashore fairings were well before that, likely before the fairing recovery program was begin in earnest.  In fact, it may have been those serendipitous discoveries which encouraged them to accelerate fairing recovery.

The fact that two fairing pieces made it to the surface intact doesn't mean they all are doing so.  There may have been luck involved.  Further, they are now experimenting with active recovery mechanisms; it is possible that failures in the active control are leading to worse outcomes (at this early point) than the passive fairings.  It's also possible that Go Searcher's primary role is to capture telemetry from the fairing, and actual recovery of pieces is not a priority.

Lastly, the ocean is a very big place.  They may well have trackers on board, but if the re-entry disables the trackers or tears them loose, Go Searcher might not be able to easily locate any remaining scraps even if they did make it to the surface.  If they know that the pieces they are interested in tend to sink after X hours, then they might not even attempt to rendezvous with any piece further than X hours travel away, so there could be luck in the prelaunch positioning of Go Searcher as well.

So there are lots of possible reasons (and I'm sure others can contribute more) why Go Searcher is still returning empty-handed despite a few instances of large fragments of fairing washing up on shore.  I don't think SpaceX needs our advice on what style of tracker and/or trained dolphin they should be using.
Title: Re: Fairing reuse
Post by: spacenut on 05/17/2016 04:27 PM
How much would a parachute, beacon, and a flotation bag add to the weight/cost?  Also, how much would a recovery boat operational costs add.  All that subtracted from the cost of the fairing? 
Title: Re: Fairing reuse
Post by: Jim on 05/17/2016 04:29 PM
It's also possible that Go Searcher's primary role is to capture telemetry from the fairing, and actual recovery of pieces is not a priority.


There is no antenna on it.

The issues is knowing how the fairing is breaking up and placing cameras/"beacons" on the pieces. 
Title: Re: Fairing reuse
Post by: RDMM2081 on 05/17/2016 06:17 PM
Go Searcher, which we believe to be the fairing recovery ship, has only gone out on the last few (three?) missions.  The washed-ashore fairings were well before that, likely before the fairing recovery program was begin in earnest.  In fact, it may have been those serendipitous discoveries which encouraged them to accelerate fairing recovery.

The fact that two fairing pieces made it to the surface intact doesn't mean they all are doing so.  There may have been luck involved.  Further, they are now experimenting with active recovery mechanisms; it is possible that failures in the active control are leading to worse outcomes (at this early point) than the passive fairings.  It's also possible that Go Searcher's primary role is to capture telemetry from the fairing, and actual recovery of pieces is not a priority.

Lastly, the ocean is a very big place.  They may well have trackers on board, but if the re-entry disables the trackers or tears them loose, Go Searcher might not be able to easily locate any remaining scraps even if they did make it to the surface.  If they know that the pieces they are interested in tend to sink after X hours, then they might not even attempt to rendezvous with any piece further than X hours travel away, so there could be luck in the prelaunch positioning of Go Searcher as well.

So there are lots of possible reasons (and I'm sure others can contribute more) why Go Searcher is still returning empty-handed despite a few instances of large fragments of fairing washing up on shore.  I don't think SpaceX needs our advice on what style of tracker and/or trained dolphin they should be using.

Interesting theories (fravorite/relevant ideas bolded), thanks for the response.

Here's another idea from left field, is it possible there are any optical telescope resources on the Go Searcher which could resolve the fairings during the end of their flight rather than the shore based systems which obviously cant resolve the fairings with much clarity once they are 300+ miles downrange?
Title: Re: Fairing reuse
Post by: Jim on 05/17/2016 06:29 PM

Here's another idea from left field, is it possible there are any optical telescope resources on the Go Searcher which could resolve the fairings during the end of their flight rather than the shore based systems which obviously cant resolve the fairings with much clarity once they are 300+ miles downrange?

No, there is nothing on the boat, optical or RF.

http://forum.nasaspaceflight.com/index.php?topic=39766.msg1526042#msg1526042
Title: Re: Fairing reuse
Post by: RDMM2081 on 05/17/2016 06:47 PM

Here's another idea from left field, is it possible there are any optical telescope resources on the Go Searcher which could resolve the fairings during the end of their flight rather than the shore based systems which obviously cant resolve the fairings with much clarity once they are 300+ miles downrange?

No, there is nothing on the boat, optical or RF.

http://forum.nasaspaceflight.com/index.php?topic=39766.msg1526042#msg1526042

Thanks for clarifying that for me. 

Can/Should they look into adding that capability, or is it presumed that the shore based optics are sufficient for them to determine what is happening to the fairings after separation well enough to inform changes to their recovery strategies?
Title: Re: Fairing reuse
Post by: kevin-rf on 05/17/2016 09:02 PM
Thanks for clarifying that for me. 

Can/Should they look into adding that capability, or is it presumed that the shore based optics are sufficient for them to determine what is happening to the fairings after separation well enough to inform changes to their recovery strategies?
SpaceX when working on the Falcon recovery problem did at one point use recoverable data pods. If they wanted, they could do the same with the fairing.

They called them Talon Pods.
Title: Re: Fairing reuse
Post by: iamlucky13 on 05/18/2016 03:34 AM
How much would a parachute, beacon, and a flotation bag add to the weight/cost?  Also, how much would a recovery boat operational costs add.  All that subtracted from the cost of the fairing? 

I'm guessing this is a bit larger than what each fairing half needs (similar size Ariane V fairing weighs 2675 kg), and it weighs 250 pounds. I'm guessing this model is static line deployed. SpaceX would need one that is mortar deployed, which will add a bit more weight. They may also need a drogue chute or ballute for stability in the upper atmosphere and initial slowing.
http://www.millsmanufacturing.com/products/cargo-parachutes/14-products/44-g-11-cargo-parachute-assembly

I'm not sure it will need a flotation bag. Most of the structure would be honeycomb, so the density should be low. I suppose bags could be used to help keep the fairing stable in the water.

I think it's generally assumed they use a cold gas thruster system to stabilize the fairing during entry. That has a weight penalty, too, but since they're already attempting re-entries, this is presumably already present. There may also be some additional TPS beyond what is normally needed for ascent.

I'm guessing all this plus integration to the fairing runs in the high 5 to low 6-figure range, not counting development costs.

It looks like offshore supply vessels like GO Searcher hire out for rates in the $10-15,000 per day range.
http://www.dnaindia.com/india/report-ongc-takes-charter-route-for-offshore-supply-vessels-1994093

So recovery costs in the 1/4 to 1/2 million dollar range don't seem inconceivable to me. There will be some refurbishment costs, too. I assume any TPS on the outside and acoustic lining on the inside will be likely places for damage. Obviously salt water exposure means a good cleaning and inspection, testing, or replacement of any parts that could corrode or be fouled by salt precipitation. My wild guesstimating leads me to think total recovery and refurbishment costs would be in the 1/2 to 1 million dollar range.

Musk's prior comment was that fairings cost "several" million dollars.
Title: Re: Fairing reuse
Post by: Spidertracks on 05/18/2016 04:54 AM
Spidertracks here - We're happy to donate a Spider to see if this might work.

They weigh 160g and can be fed with 10-32vDC drawing 1A every two-mins so a small battery should keep it alive long enough.

We attached one to a weather balloon recently and sent it skywards and it managed to get as high as 104,000ft with the Spider tracking every two-mins. We were able to put the Spider coords into our GPS and go right to the device when back on the ground. Video here - https://www.youtube.com/watch?v=tOOQ47mUfF4 (https://www.youtube.com/watch?v=tOOQ47mUfF4)

But I'm also with Kevin, smoke would be a nice touch too.

Off the shelf: https://www.iridium.com/products/details/spidertracks-satellite-tracking

Quote
Spidertracks Satellite Tracking

Spidertracks is more than just a tracking system: as well as knowing exactly where people and valuable assets are at any moment in time, it can also tell you how they are. If something goes wrong, and the website loses contact with the spider device, the system will automatically send text and email alerts to the right people, including rescue services, within minutes of the accident occurring. Because the alert is generated by the system, it doesn’t rely on the device surviving an accident, so it will always be sent, enabling rescue services to locate the site quickly based on the last transmitted position. With Spidertracks, no one needs to be lost at sea, on land, or in the air again.

It combines a portable tracking unit, the Spider, with a web-based client interface, enabling users to access their flight following and tracking details from anywhere at any time via the internet. Powered by a 10 V – 32 V power source, it has no external antenna and can be moved between aircraft or vehicles, so it doesn’t require expensive installation or certification. Partnered with Iridium, it offers global coverage.

Spidertracks also offers simple two-way global communication. Customers can send and receive texts with a compatible phone from anywhere on earth, via Iridium, through the Spidertracks website—ideal for anyone who needs to communicate from a remote region without GSM/cellphone coverage.

The unit is portable, with the tracks accessed from any internet connected device, and it is AFF compliant, offering a cost-effective, simple and reliable tracking-based safety system for anyone working or traveling in remote locations or risky situations.

Problem solved. Though, adding a smoke generator and disco lights would be a nice touch.
Title: Re: Fairing reuse
Post by: kevin-rf on 05/18/2016 10:49 AM
But no disco lights?
Title: Re: Fairing reuse
Post by: Hobbes-22 on 05/18/2016 05:24 PM

If all the following are true, then what has stopped them before?

1)  SpaceX are and have been interested in fairing recovery
2)  The fairing's are trackable via range radar
3)  One landed intact enough to float to shore

Was the Bahamas fairing making it to shore unclaimed a case where they were simply not interested in tracking it down and attempting recovery?

What would be the point in recovering scrap?
Title: Re: Fairing reuse
Post by: RDMM2081 on 05/18/2016 05:36 PM

If all the following are true, then what has stopped them before?

1)  SpaceX are and have been interested in fairing recovery
2)  The fairing's are trackable via range radar
3)  One landed intact enough to float to shore

Was the Bahamas fairing making it to shore unclaimed a case where they were simply not interested in tracking it down and attempting recovery?

What would be the point in recovering scrap?

Identify weak points in the fairing design, either to strengthen those points of failure, or modify their recovery system to avoid creating loads which lead to that type of failure.
Title: Re: Fairing reuse
Post by: Lar on 05/18/2016 05:58 PM
Spidertracks here - We're happy to donate a Spider to see if this might work.

I would think SpaceX doesn't need a donation, they have money... (but maybe you give them one for their use in exchange for featuring them in your adverts?)

Also I think lights are better than smoke, usually smoke from electronics is not a good sign :)

Also, welcome to the forums, what an awesome first post!!!!
Title: Re: Fairing reuse
Post by: Hobbes-22 on 05/18/2016 06:49 PM

If all the following are true, then what has stopped them before?

1)  SpaceX are and have been interested in fairing recovery
2)  The fairing's are trackable via range radar
3)  One landed intact enough to float to shore

Was the Bahamas fairing making it to shore unclaimed a case where they were simply not interested in tracking it down and attempting recovery?

What would be the point in recovering scrap?

Identify weak points in the fairing design, either to strengthen those points of failure, or modify their recovery system to avoid creating loads which lead to that type of failure.

Sure, that has value when they start adding a recovery system to the fairing. I had the impression the Bahamas fairing (and all fairings before that) didn't have any recovery system, so the only thing they'd learn from recovering those would be the amount of damage an unbraked sea impact does. That has limited usefulness in my opinion, so to answer your question, that's what stopped them before.
Title: Re: Fairing reuse
Post by: kevin-rf on 05/18/2016 07:13 PM
Sure, that has value when they start adding a recovery system to the fairing. I had the impression the Bahamas fairing (and all fairings before that) didn't have any recovery system, so the only thing they'd learn from recovering those would be the amount of damage an unbraked sea impact does. That has limited usefulness in my opinion, so to answer your question, that's what stopped them before.

Here is the odd thing about that. They attached a Go-Pro to it. A very odd thing to do if you have zero chance of getting it back. I wonder if they where hoping on an off chance of getting one back someday. And now one has washes ashore they are going, hmmm.....

I do think going from recovering a fairing to reflying it will be a stretch. You are going from a clean room environment to a swim and then have to clean it so it can again be used in a clean room. No saying it's impossible, but...
Title: Re: Fairing reuse
Post by: rickyramjet on 05/19/2016 04:01 AM
Sure, that has value when they start adding a recovery system to the fairing. I had the impression the Bahamas fairing (and all fairings before that) didn't have any recovery system, so the only thing they'd learn from recovering those would be the amount of damage an unbraked sea impact does. That has limited usefulness in my opinion, so to answer your question, that's what stopped them before.

Here is the odd thing about that. They attached a Go-Pro to it. A very odd thing to do if you have zero chance of getting it back. I wonder if they where hoping on an off chance of getting one back someday. And now one has washes ashore they are going, hmmm.....

I do think going from recovering a fairing to reflying it will be a stretch. You are going from a clean room environment to a swim and then have to clean it so it can again be used in a clean room. No saying it's impossible, but...
I would have assumed there was live video being transmitted back to SpaceX, that they wouldn't have relied on random chance to provide them a video.  Also, the fairing was built in a non-clean room environment, so I see no problem reusing one after clean up.  Perhaps they hope to snatch the fairings before they reach the ocean with some type of mid-air retrieval, so no salt water contamination.
Title: Re: Fairing reuse
Post by: envy887 on 05/19/2016 02:06 PM
...
Perhaps they hope to snatch the fairings before they reach the ocean with some type of mid-air retrieval, so no salt water contamination.

This seems like the most reusability-friendly solution. Surviving re-entry is hard enough, no point in building it to survive impact with the ocean if they don't have to. A small chute, a long line, and a rather large helicopter should do. But first they have to get it down the lower atmosphere in one piece and track where it's going accurately enough to be there waiting.
Title: Re: Fairing reuse
Post by: LouScheffer on 05/19/2016 07:15 PM
You are going from a clean room environment to a swim and then have to clean it so it can again be used in a clean room. No saying it's impossible, but...
The people who work in a clean room do exactly this every day.  Plus people are harder to pressure-wash or steam clean than fairings.
Title: Re: Fairing reuse
Post by: Kaputnik on 05/19/2016 07:28 PM
...
Perhaps they hope to snatch the fairings before they reach the ocean with some type of mid-air retrieval, so no salt water contamination.

This seems like the most reusability-friendly solution. Surviving re-entry is hard enough, no point in building it to survive impact with the ocean if they don't have to. A small chute, a long line, and a rather large helicopter should do. But first they have to get it down the lower atmosphere in one piece and track where it's going accurately enough to be there waiting.

I don't have the numbers to hand... what is the downrange impact distance of the fairing? A big helicopter has a working radius of aronud 200nm so might not be enough to reach the area. Would this need a ship-based helicopter?
Title: Re: Fairing reuse
Post by: kevin-rf on 05/19/2016 08:23 PM
You are going from a clean room environment to a swim and then have to clean it so it can again be used in a clean room. No saying it's impossible, but...
The people who work in a clean room do exactly this every day.  Plus people are harder to pressure-wash or steam clean than fairings.
Never seen anyone pressure wash sound insulation like what is found inside a fairing... My point is that the fairing will be encasing something that has lived all it's life in a clean room. The inside of a fairing is not a solid hard surface that you can just apply some elbow grease to.
Title: Re: Fairing reuse
Post by: D_Dom on 05/19/2016 08:42 PM
Maybe, if you planned on R&R of the insulation? Nooks and Crannies could be avoided with sufficient detail design.
Title: Re: Fairing reuse
Post by: LouScheffer on 05/20/2016 12:17 AM
You are going from a clean room environment to a swim and then have to clean it so it can again be used in a clean room. No saying it's impossible, but...
The people who work in a clean room do exactly this every day.  Plus people are harder to pressure-wash or steam clean than fairings.
Never seen anyone pressure wash sound insulation like what is found inside a fairing... My point is that the fairing will be encasing something that has lived all it's life in a clean room. The inside of a fairing is not a solid hard surface that you can just apply some elbow grease to.
Sound insulation is not very structurally strong, or heat resistant, or wind proof.  I would guess they would strip off the soft stuff, carefully wash and inspect the structural parts, then re-apply the soundproofing.  Most of the cost of the fairing has to be in the large composite pieces, not the sound insulation.
Title: Re: Fairing reuse
Post by: envy887 on 05/20/2016 12:21 AM
...
Perhaps they hope to snatch the fairings before they reach the ocean with some type of mid-air retrieval, so no salt water contamination.

This seems like the most reusability-friendly solution. Surviving re-entry is hard enough, no point in building it to survive impact with the ocean if they don't have to. A small chute, a long line, and a rather large helicopter should do. But first they have to get it down the lower atmosphere in one piece and track where it's going accurately enough to be there waiting.

I don't have the numbers to hand... what is the downrange impact distance of the fairing? A big helicopter has a working radius of aronud 200nm so might not be enough to reach the area. Would this need a ship-based helicopter?

Or a barge based helo...
Title: Re: Fairing reuse
Post by: bioelectromechanic on 05/28/2016 09:49 AM
Fairing sep earlier on this one?
Title: Re: Fairing reuse
Post by: southshore26 on 05/28/2016 01:23 PM
Didn't seem like it.
Title: Re: Fairing reuse
Post by: Silmfeanor on 06/02/2016 08:54 PM
https://twitter.com/elonmusk/status/738471747540783104 (https://twitter.com/elonmusk/status/738471747540783104)

in response to a question: Are RCS thrusters the sole component for fairing recovery? Are chutes required?

Quote
@mattyteare @karaswisher @waltmossberg @YouTube autosteering chutes will be added soon

So, we'll perhaps see some fairing halves coming back under chutes!
Title: Re: Fairing reuse
Post by: AncientU on 06/02/2016 09:07 PM
Soon!

Wonder how far a self-steering chute could travel from the top of the atmosphere?
Hundreds of miles??? Seems doubtful, but gliders do travel that far from few 10k ft releases.
Title: Re: Fairing reuse
Post by: bstrong on 06/02/2016 09:41 PM
A bit of googling on "autosteering chutes" turns up that there are some available from the folks who make the Dragon chutes that sound pretty close to their needs. I wasn't expecting this to be available off-the-shelf.

Quote
Nov 7/12: JPADS 10k. HDT Global subsidiary Airborne Systems announces that their “Dragonfly external link” JPADS 10K is in full rate production, with the first 243 type classified systems set to be delivered by April 2013.

The renamed JPADS 10K is the 2nd type classified JPADS platform to be fielded by the U.S. military. Unlike the lighter JPADS 2K’s 150m accuracy, the 10,000 pound capacity JPADS 10K is accurate only to within 250 meters. On the other hand, it can be used with Type V airdrop platforms to carry vehicles like Humvees, artillery pieces like an M777, or irregularly shaped items like shelters, generators, etc.

http://www.defenseindustrydaily.com/jpads-making-precision-airdrop-a-reality-0678/
Title: Re: Fairing reuse
Post by: Jim on 06/03/2016 01:26 AM
Soon!

Wonder how far a self-steering chute could travel from the top of the atmosphere?
Hundreds of miles??? Seems doubtful, but gliders do travel that far from few 10k ft releases.

The chutes wouldn't come out until much lower in the atmosphere.  The ACS on the fairing is to keep it oriented until it is lower.
Title: Re: Fairing reuse
Post by: envy887 on 06/03/2016 02:05 AM
Soon!

Wonder how far a self-steering chute could travel from the top of the atmosphere?
Hundreds of miles??? Seems doubtful, but gliders do travel that far from few 10k ft releases.

The chutes wouldn't come out until much lower in the atmosphere.  The ACS on the fairing is to keep it oriented until it is lower.

Gliders ride thermals to get that distance and have better glide ratios than chutes. Tens of miles is more likely. Think they will try to land it on a ship?
Title: Re: Fairing reuse
Post by: arsenal on 06/03/2016 06:52 AM
Soon!

Wonder how far a self-steering chute could travel from the top of the atmosphere?
Hundreds of miles??? Seems doubtful, but gliders do travel that far from few 10k ft releases.

The chutes wouldn't come out until much lower in the atmosphere.  The ACS on the fairing is to keep it oriented until it is lower.

Gliders ride thermals to get that distance and have better glide ratios than chutes. Tens of miles is more likely. Think they will try to land it on a ship?
My guess would be similar to what they did with recovering the first stage. First they will pick a target in the ocean and see how close they can get to it. Additionally, this time they probably will send one of their boats try and recover it since unlike the first stage a fairing will probably stay in tact on impact with water. Then they may potentially try to land it on a ship, but I doubt it would be the same on that the first stage lands on. Pretty high chance that stuff collides.
Title: Re: Fairing reuse
Post by: Kaputnik on 06/03/2016 06:59 AM
A mid-air capture by a helicopter would seem feasible, but a fairly expensive exercise- especially as you'd need two. But any other option means either splashing the fairing, or fitting (heavy) equipment to deal with impact. Plus I really doubt a steerable chute could have the accuracy to get it down onto a boat anyway.
Title: Re: Fairing reuse
Post by: savuporo on 06/03/2016 07:28 AM
Plus I really doubt a steerable chute could have the accuracy to get it down onto a boat anyway.
Military precision airdrop steerable parafoils ( Atair, MMIST, SPADES, Zodiac etc) had accuracy of about 50-200 meters ~8 years ago. Depending on payload size and drop altitude of course. Not hitting a barge with that, but i guess military never had a land on a dime requirement.
Title: Re: Fairing reuse
Post by: envy887 on 06/03/2016 01:29 PM
Plus I really doubt a steerable chute could have the accuracy to get it down onto a boat anyway.
Military precision airdrop steerable parafoils ( Atair, MMIST, SPADES, Zodiac etc) had accuracy of about 50-200 meters ~8 years ago. Depending on payload size and drop altitude of course. Not hitting a barge with that, but i guess military never had a land on a dime requirement.
Maybe the boat can drive the last 50-100m to get under the fairing. It doesn't have to land on a droneship, since a fairing coming down under a chute isn't all that dangerous... mass in only ~2t, terminal velocity is probably a few m/s, and there's no explosives aboard. Land it on a airbag sitting on the deck.
Title: Re: Fairing reuse
Post by: Kaputnik on 06/03/2016 05:14 PM
Look up the old episode of Top Gear (UK) where they tried to land a stunt parachutist in the back seat of a convertible car. It took a whole day of filming before they got it right.

My bet is
A) splash the stage, write off the foam but reuse the composite structure.
B) Much less likely, snag it out of the air with a pair of helicopters. But replacing the foam might be cheaper.
Title: Re: Fairing reuse
Post by: Lar on 06/03/2016 05:20 PM
Look up the old episode of Top Gear (UK) where they tried to land a stunt parachutist in the back seat of a convertible car. It took a whole day of filming before they got it right.

My bet is
A) splash the stage, write off the foam but reuse the composite structure.
B) Much less likely, snag it out of the air with a pair of helicopters. But replacing the foam might be cheaper.

Er, splash the FAIRING... they tried the "splash the stage" thing already :)

As for the landing in a convertable, you don't really have x and y authority, all you can do is turn... with thrusters an ASDS like catcher could move in any desired direction.

I agree that replacing the foam is probably cheaper than helicopters ... especially because you have to figure out how to base them at sea since they don't have the range/loiter to fly out 500 nm, loiter around through a whole launch cycle and return.
Title: Re: Fairing reuse
Post by: AncientU on 06/03/2016 05:27 PM
Soon!

Wonder how far a self-steering chute could travel from the top of the atmosphere?
Hundreds of miles??? Seems doubtful, but gliders do travel that far from few 10k ft releases.

The chutes wouldn't come out until much lower in the atmosphere.  The ACS on the fairing is to keep it oriented until it is lower.

Understand using ACS to control orientation until it hits the top of the atmosphere, and control that part of the descent where parachutes are useless, but wondering how high the parachute could deploy and how far it could travel back toward land to see if it is possible to get back to within helecopter flight range of the launch site or where ever helos can fly from.
Title: Re: Fairing reuse
Post by: Chris_Pi on 06/03/2016 06:20 PM
Soon!

Wonder how far a self-steering chute could travel from the top of the atmosphere?
Hundreds of miles??? Seems doubtful, but gliders do travel that far from few 10k ft releases.

The chutes wouldn't come out until much lower in the atmosphere.  The ACS on the fairing is to keep it oriented until it is lower.

Understand using ACS to control orientation until it hits the top of the atmosphere, and control that part of the descent where parachutes are useless, but wondering how high the parachute could deploy and how far it could travel back toward land to see if it is possible to get back to within helecopter flight range of the launch site or where ever helos can fly from.

I was was thinking the same about the possibility for the fairing to fly itself back. It's already pretty light for it's size, Adding parachutes might be more for the steering than anything else. Paragliders https://en.wikipedia.org/wiki/Paragliding (https://en.wikipedia.org/wiki/Paragliding) can manage a 9:1-16:1 glide ratio. Get the parachutes open nice and high and a fairing could cover a whole lot of distance back towards land.
Title: Re: Fairing reuse
Post by: manoweb on 06/03/2016 06:24 PM
especially because you have to figure out how to base them at sea since they don't have the range/loiter to fly out 500 nm, loiter around through a whole launch cycle and return.

What was ULA's plan to recover the engines then?

Title: Re: Fairing reuse
Post by: Jim on 06/03/2016 06:44 PM
but wondering how high the parachute could deploy and how far it could travel back toward land to see if it is possible to get back to within helecopter flight range of the launch site or where ever helos can fly from.

It takes different chutes for different altitudes,  Chutes for landing are usually deployed low in the atmosphere, 10kft.  They have issues opening higher.  Drogues open around 50kft.  There isn't going to be a parafoil that will open at high altitudes.
Title: Re: Fairing reuse
Post by: envy887 on 06/03/2016 06:45 PM
especially because you have to figure out how to base them at sea since they don't have the range/loiter to fly out 500 nm, loiter around through a whole launch cycle and return.

What was ULA's plan to recover the engines then?

The Falcon 9 1st stage engines and thrust structure weigh more than 12,000 kg, and Vulcan would probably be heavier. Would need multiple choppers or a heavy airplane to catch that.
Title: Re: Fairing reuse
Post by: cambrianera on 06/03/2016 06:59 PM
especially because you have to figure out how to base them at sea since they don't have the range/loiter to fly out 500 nm, loiter around through a whole launch cycle and return.

What was ULA's plan to recover the engines then?

The Falcon 9 1st stage engines and thrust structure weigh more than 12,000 kg, and Vulcan would probably be heavier. Would need multiple choppers or a heavy airplane to catch that.
Nine M1D engines are about 4000 kg, octaweb and piping should be one ton.
Title: Re: Fairing reuse
Post by: Lar on 06/03/2016 07:01 PM
especially because you have to figure out how to base them at sea since they don't have the range/loiter to fly out 500 nm, loiter around through a whole launch cycle and return.

What was ULA's plan to recover the engines then?

The Falcon 9 1st stage engines and thrust structure weigh more than 12,000 kg, and Vulcan would probably be heavier. Would need multiple choppers or a heavy airplane to catch that.
We do have threads to cover SMART, probably should review those, IIRC some of these questions were answered... To this specific question I don't think the engines return nearly as far down range as a fairing does so it's within reach of a land based helo to get them.

Not sure this is the best thread but it's a start  http://forum.nasaspaceflight.com/index.php?topic=37777
This one also has a lot of good background and links to papers and presentations:  http://forum.nasaspaceflight.com/index.php?topic=38403
Title: Re: Fairing reuse
Post by: sewebster on 06/03/2016 08:20 PM
I agree that replacing the foam is probably cheaper than helicopters ... especially because you have to figure out how to base them at sea since they don't have the range/loiter to fly out 500 nm, loiter around through a whole launch cycle and return.

You can do in-air refueling of helicopters.

Basing them at sea.... whoa... I mean, we just figured out how to land a simple rocket on a ship, now suddenly you're talking about moving directly to something with huge spinning blades!
Title: Re: Fairing reuse
Post by: Robotbeat on 06/03/2016 08:25 PM
Or use an airplane to recover them. Doesn't have to be a helicopter. Corona used airplanes. Seems like it'd be cheaper, faster, maybe safer. Airplanes are lower maintenance, can cover a much longer range, and SpaceX already uses them sometimes just for observing the booster recovery attempts.

Once a fairing halve is caught by the plane, however, I'm not entirely sure how it'd be gently placed on the ground.
Title: Re: Fairing reuse
Post by: Lar on 06/03/2016 08:30 PM
I agree that replacing the foam is probably cheaper than helicopters ... especially because you have to figure out how to base them at sea since they don't have the range/loiter to fly out 500 nm, loiter around through a whole launch cycle and return.

You can do in-air refueling of helicopters.

Basing them at sea.... whoa... I mean, we just figured out how to land a simple rocket on a ship, now suddenly you're talking about moving directly to something with huge spinning blades!
SpaceX optimizes for cost. Are you sure that in-air refueling of not one, but two, helos is going to be the cheapest way? If not, are you sure that basing them on a ship is going to be the cheapest?
Title: Re: Fairing reuse
Post by: sewebster on 06/03/2016 08:43 PM
I agree that replacing the foam is probably cheaper than helicopters ... especially because you have to figure out how to base them at sea since they don't have the range/loiter to fly out 500 nm, loiter around through a whole launch cycle and return.

You can do in-air refueling of helicopters.

Basing them at sea.... whoa... I mean, we just figured out how to land a simple rocket on a ship, now suddenly you're talking about moving directly to something with huge spinning blades!
SpaceX optimizes for cost. Are you sure that in-air refueling of not one, but two, helos is going to be the cheapest way? If not, are you sure that basing them on a ship is going to be the cheapest?

Don't forget the other helicopters with high speed cameras live streaming to the public!

Yeah, sorry, my whole post was basically supposed to be sarcastic. And I realize you were actually advocating against the ship-based concept. Here's the translation of my post:

"Basing helicopters on ships is pretty much a solved problem if they wanted to go that way... but I'm guessing they will try to avoid something like that if at all possible to reduce costs.
Title: Re: Fairing reuse
Post by: arsenal on 06/03/2016 09:15 PM
Another factor is wind. Not sure how well the parachutes will be able to steer in heavy wind. There will probably be some severe restrictions to where you can aim the chutes based on the weather conditions.
Title: Re: Fairing reuse
Post by: Kaputnik on 06/03/2016 10:15 PM
Do we genuinely think that splashing the fairing halves is a no-go? They must be relatively sturdy to withstand aero loads, and are nowhere near the size/scale of a first stage.
Title: Re: Fairing reuse
Post by: manoweb on 06/03/2016 10:29 PM
Kaputnik, I was under the impression that the expensive part of the fairings, the composite, can survive a splash down and not be damaged by saltwater.
Title: Re: Fairing reuse
Post by: georgegassaway on 06/03/2016 10:53 PM
Or use an airplane to recover them. Doesn't have to be a helicopter. Corona used airplanes.
……
Once a fairing halve is caught by the plane, however, I'm not entirely sure how it'd be gently placed on the ground.

Fairings way too big and flimsy (once in separated halves) to use a plane.  Air-snag of satellites, they were around 3 feet diameter and very robust.

And even if they could survive, no way to land them gently as you noted (Discoverer/Coronas were winched inside of the open back section of a C-117 Flying Boxcar).

Another factor is wind. Not sure how well the parachutes will be able to steer in heavy wind. There will probably be some severe restrictions to where you can aim the chutes based on the weather conditions.

An airborne vehicle can “steer” fine once it is off the ground and into the air.  Wind direction and velocity is not a factor for steering.  Severe turbulence can be.

Keep in mind for example that if a hot air balloon is a few hundred feet up flying in 10 mph wind, from the perspective of those on board, the balloon is in calm air, while the ground is moving at 10 mph.

One good thing is that over the ocean there does not tend to be as much turbulence as occurs over land due to trees, buildings, mountains, and thermal activity from uneven heating of the ground.

With a smart enough autonomous steering system for chutes, it could turn into the wind to use a headwind for a slower landing into the water.  Say if a 30 mph glide speed and 15 mph wind, fly into the wind for a net 15 mph horizontal velocity (which of course human parachutists do, usually with some nearby wind direction indicator such as windsock or smoke canister).  There are various means that it could use to determine the wind direction while over the water, such as comparing the  GPS based horizontal velocity and  with the indicated airspeed, while in a wide circle (or flying a rounded-square pattern) to derive the likely wind direction and speed.

I am not saying I think landing by chute into the water is how they’d do it vs say grabbing in midair by helicopter.  Just noting that an airplane type of air-snag seems unfeasible, and that in the most basic sense wind does NOT make it harder to steer (Landing during a very serious storm, that would be a different issue, as that would be a problem for any system.  Any air-snag during a storm, a risk of mid-air collision and loss of crew. ).  If K.I.S.S. rules, then chutes into water would seem the most practical. Unless there's a really big reason why salt-water landing is not good even though they are mostly composite (since they are not 100.00% composite, possibly some critical not-practical-to-replace components might be affected)

However, I just got to thinking about the aerodynamic interaction of  steerable chutes and the relatively lightweight  very large fairings.   I would hope that the suspension lines would put the fairing at a horizontal or near horizontal angle, in such a way that the rear edges of the fairing would act like rudders to keep the fairing pointed into the wind. Otherwise might need a little tail chute at the back of the fairing to keep the nose pointed into the airflow, as often used with long-distance helicopter transport of cargo to keep it from spinning around.
Title: Re: Fairing reuse
Post by: DAZ on 06/03/2016 11:05 PM
You can probably can get between a 4/1 to 8/1 glide ratio off the parachutes.  It really depends on how much weight you want to use for the parachutes.  The other downside to a better glide ratio, other than weight, is the ability to glide into the wind.  If the wind is too high for the glide ratio you might actually be going backwards.  Although it is probably the most desirable to glide all the way back to the ship probably the best reason to have them glide is so they can meet at the same known points for recovery.

So depending on deployment height/winds they could possibly glide for as little as 4 miles with a 4/1 and deployment at 5000 feet.  If deployed at 35,000 to 45,000 feet you could possibly get between 25 and 50 miles.  You could definitely employ them higher than this but it might not gain you as much as you might think.  The glide ratios at let’s say 80,000 feet might be closer to 1/1 and would leave them subjected to high-altitude wind’s.  It might be better to get through these wind’s faster than trying to glide through them.

It has got to be cheaper, not to mention less costly, to try to find and recover 2 mostly submerged/bobbing fairings a quarter-mile from each other (at a predetermined known location) than to try to find those same fairings someplace within 100 square miles separated by something like 50 miles of ocean.

I really don’t see how the fairings can be so damaged by a little immersion in salt water that it could possibly justify the cost of a helicopter recovery.  And really what you’re talking about here is 2 long-range helicopters.  Most of the parts should be safe from a little salt water immersion, they would just get rinsed off once they’re on board the ship.  The few parts that absolutely can’t be made to tolerate the salt water have just got to be cheaper to be replaced than the cost of a helicopter recovery.
Title: Re: Fairing reuse
Post by: friendly3 on 06/04/2016 01:12 AM
The few parts that absolutely can’t be made to tolerate the salt water have just got to be cheaper to be replaced than the cost of a helicopter recovery.

No, the few parts that absolutely can’t be made to tolerate the salt water and the cost of a boat recovery have just got to be cheaper to be replaced than the cost of a helicopter recovery.
Title: Re: Fairing reuse
Post by: oiorionsbelt on 06/04/2016 01:18 AM
Seems as though ya just need to get them down rather gently and pick em up rather quickly.
Title: Re: Fairing reuse
Post by: tleski on 06/04/2016 03:06 AM
Seems as though ya just need to get them down rather gently and pick em up rather quickly.

I think the first photo (the one with the flag) shows a fragment of the interstage, not fairing.
Title: Re: Fairing reuse
Post by: CJ on 06/04/2016 03:28 AM
Something to bear in mind regarding helicopters (or planes, for that matter); range does not mean the same thing for military craft as it does for civilian. The military definition is usually out and back, whereas the civilian is one-way.

Another factor with helicopters; is they are carrying their cargo underslung (outside), range will be significantly decreased over carrying it internal.

Here's an article of how NASA tried to do a mid-air retrieval, via helicopter, of the Genisis probe.  (that's the one that crashed due to chute failure). http://www.space.com/281-sky-capture-nasa-bring-genesis-earth.html

So, seeing as how the fairings would tend to come down not too far (50 miles?) from the ASDS on non-boostback-burn missions, I wonder if it's feasible to use the ASDS as a launch point for the helicopters; they ride out on the ASDS, take off a few minutes before launch, snag the fairings, and lower them to either the support ship or ASDS deck. (I strongly suspect the former.) and then fly to shore.  You'd need helicopters with longer than normal range (some have that kind of range, and others can have an extra fuel tank added). I think the timing would be pretty daunting, so perhaps it'd be better (also from a cost perspective, perhaps) to emulate what the Air Force did way back in 1960 and after; use a cargo plane. 
Title: Re: Fairing reuse
Post by: Comga on 06/04/2016 04:20 AM
(snip)
So, seeing as how the fairings would tend to come down not too far (50 miles?) from the ASDS on non-boostback-burn missions, I wonder if it's feasible to use the ASDS as a launch point for the helicopters; they ride out on the ASDS, take off a few minutes before launch, snag the fairings, and lower them to either the support ship or ASDS deck. (I strongly suspect the former.) and then fly to shore.  You'd need helicopters with longer than normal range (some have that kind of range, and others can have an extra fuel tank added). I think the timing would be pretty daunting, so perhaps it'd be better (also from a cost perspective, perhaps) to emulate what the Air Force did way back in 1960 and after; use a cargo plane. 

At the risk of going farther down the rabbit hole....
A big problem with staging helicopters from the ASDS is what happens if they fail to take off?  They would have people and a helicopter on the ASDS. That would probably mean calling off the booster recovery.
Title: Re: Fairing reuse
Post by: The Amazing Catstronaut on 06/04/2016 04:55 AM
Salt water isn't really good for anything metallic (see STS SRBs), but helicopters cut into the fairing reuse cost. Are we completely sure that helicopter recovery is what they intend to do? Are there any alternative methods for ensuring the fairing doesn't end up in the drink?

Edit: If air recovery truly is the way to go, a fixed winged aircraft does indeed seem preferable. Helicopters are not fun to fly far over water notwithstanding. A pity there isn't a sufficiently large drone.
Title: Re: Fairing reuse
Post by: IntoTheVoid on 06/04/2016 05:29 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
Title: Re: Fairing reuse
Post by: CJ on 06/04/2016 05:31 AM
(snip)
So, seeing as how the fairings would tend to come down not too far (50 miles?) from the ASDS on non-boostback-burn missions, I wonder if it's feasible to use the ASDS as a launch point for the helicopters; they ride out on the ASDS, take off a few minutes before launch, snag the fairings, and lower them to either the support ship or ASDS deck. (I strongly suspect the former.) and then fly to shore.  You'd need helicopters with longer than normal range (some have that kind of range, and others can have an extra fuel tank added). I think the timing would be pretty daunting, so perhaps it'd be better (also from a cost perspective, perhaps) to emulate what the Air Force did way back in 1960 and after; use a cargo plane. 

At the risk of going farther down the rabbit hole....
A big problem with staging helicopters from the ASDS is what happens if they fail to take off?  They would have people and a helicopter on the ASDS. That would probably mean calling off the booster recovery.

Hrmmm. I think you're right - they'd have to skip the F9 recovery. That, plus other factors (such as the tight margins for them getting back to land) probably make this a bad idea.

A fixed wing old cargo plane, on the other hand, would be easier, cheaper, and not potentially hinder F9 recovery. Water recovery would be even better IMHO, if (and that's a mighty big if) the fairings can tolerate salt water landing and immersion.



Title: Re: Fairing reuse
Post by: OnWithTheShow on 06/04/2016 05:39 AM

Quote

Hrmmm. I think you're right - they'd have to skip the F9 recovery. That, plus other factors (such as the tight margins for them getting back to land) probably make this a bad idea.


Plenty of ships with helipads out there to rent.
Title: Re: Fairing reuse
Post by: guckyfan on 06/04/2016 05:46 AM
They can use a ship with helipad. But what when they have caught the bus? The helicopter would likely not have the range to get to land from there. How to land the fairing under parachute on a ship? Something with a flat area as large as the big barges may be needed. It would not necessarily need station keeping thrusters.
Title: Re: Fairing reuse
Post by: Kaputnik on 06/04/2016 05:52 AM
Are we completely sure that helicopter recovery is what they intend to do?

No, everything is speculation at this point.
Title: Re: Fairing reuse
Post by: DAZ on 06/04/2016 02:28 PM
As with most experiments on recovery that SpaceX does, they start with the simplest/cheapest options they can think of and only add more complexity/cost when they find those solutions are not tenable/optimal.  At the moment the simplest/cheapest option would appeared to let the fairing just splash into the ocean and then tow them back to land or possibly to the barge.  Even if SpaceX ultimately thinks this may not be the final working solution this is probably where they will start until they actually get fairings back and see how they fare their ordeal.  This is how they are doing it with the returning stages. After they have these fairings in hand and can inspect them only then will they determine what additional modifications they might make.  So even if SpaceX is thinking that they might need to ultimately use aircraft retrieval for these fairings the 1st recoveries we observe will still probably be those from the ocean.
Title: Re: Fairing reuse
Post by: georgegassaway on 06/04/2016 07:12 PM
DAZ,  what you say makes a lot of sense.

First they need to get one or two fairings back just to see what shape they are in after enduring re-entry and splashdown in the ocean with whatever type of chute is used (probably simple non-steerable).  Also, likely documentation with several GoPros (they did that with one GoPro years ago, for more serious testing they’d use several plus a likely small “black box” to record all sorts of sensor data including G sensors).  I also would suspect the fairings themselves do not tend to float (unless they have a honeycomb construction or some other fabrication method that adds buoyancy as a side benefit), so they may need to add some buoyancy to them such as foam (K.I.S.S.) or inflatable air bags (If they use a ballute to help with re-entry, that could do double duty as a “bouy” after landing)

If  the fairings are badly damaged by re-entry heating or aerodynamic loads, that would be a key upstream problem to work on , such as perhaps a “Ballute” system to cause enough high drag (and stability) during re-entry to make the heating effects gentler (and the fairings may not be practical to make them aerodynamically stable without some deployable system such as ballute or far more complex means).

So once they get 1-2 back and learn what needs to be done, and what is fine as-is, they can move on with upgrades and determine whether a parachute landing into the ocean is good enough, to refine the chute system, or if they have to try to snag it with a copter (To me the only good reason for copter air-snag would be if the fairings can't get soaked in saltwater).

I am 99%+ sure that an “airplane” based horizontal air-snag recovery is totally impractical.  The aerodynamic and mass forces of a small  Discoverer / Corona satellite being snagged horizontally, and the forces of the relatively HUGE fairing halves are orders of magnitude differences.  Indeed the fairings are also relatively flimsy once separated, they would tend to deform and rip due to the massive loads of the air-snag, as well as spin and wobble like crazy until ripping apart.  To “reel one inside” the fuselage, would require a cargo plane of about the size of a C-5 , and one heck of a method to stabilize the fairing half so it could be reeled inside the rear opening.  Actually I am not even sure a fairing would be small enough to fit thru the rear ramp door of a C-5, and it seems so unlikely that a horizontal air-snag by airplane could be practical that I’m not inclined to go look up the stats on fairing dimensions vs C-5 or other very large cargo aircraft.
Title: Re: Fairing reuse
Post by: Kabloona on 06/05/2016 12:03 AM
Quote
  I also would suspect the fairings themselves do not tend to float (unless they have a honeycomb construction or some other fabrication method that adds buoyancy as a side benefit),

The fairings do have a honeycomb core and we've already seen at least one fairing half wash up on shore (the one from which the GoPro video of fairing descent was recovered). Additional flotation wouldn't hurt, of course, but the fairings are likely quite buoyant already.
Title: Re: Fairing reuse
Post by: Bob Shaw on 06/05/2016 12:35 AM
'Buoyant' is pretty easy. Using the suckers again is hard.
Title: Re: Fairing reuse
Post by: ppb on 06/05/2016 12:52 AM
Plus I really doubt a steerable chute could have the accuracy to get it down onto a boat anyway.
Military precision airdrop steerable parafoils ( Atair, MMIST, SPADES, Zodiac etc) had accuracy of about 50-200 meters ~8 years ago. Depending on payload size and drop altitude of course. Not hitting a barge with that, but i guess military never had a land on a dime requirement.
Maybe the boat can drive the last 50-100m to get under the fairing. It doesn't have to land on a droneship, since a fairing coming down under a chute isn't all that dangerous... mass in only ~2t, terminal velocity is probably a few m/s, and there's no explosives aboard. Land it on a airbag sitting on the deck.
I really like this idea if salt water immersion is an obstacle to reuse. After a few notable learning experiences (see e.g. F1 fuel slosh failure) Spacex has proven themselves to harbor a pretty good stable of controls engineers. I wouldn't be surprised if they could reduce parafoil CEP to the point where the ship catcher wouldn't have to move much at all (Yes, I know analysis without numbers is just an opinion, to quote another poster's byline)

Sent from my LGLS885 using Tapatalk

Title: Re: Fairing reuse
Post by: Bob Shaw on 06/05/2016 01:10 AM
Plus I really doubt a steerable chute could have the accuracy to get it down onto a boat anyway.
Military precision airdrop steerable parafoils ( Atair, MMIST, SPADES, Zodiac etc) had accuracy of about 50-200 meters ~8 years ago. Depending on payload size and drop altitude of course. Not hitting a barge with that, but i guess military never had a land on a dime requirement.
Maybe the boat can drive the last 50-100m to get under the fairing. It doesn't have to land on a droneship, since a fairing coming down under a chute isn't all that dangerous... mass in only ~2t, terminal velocity is probably a few m/s, and there's no explosives aboard. Land it on a airbag sitting on the deck.
I really like this idea if salt water immersion is an obstacle to reuse. After a few notable learning experiences (see e.g. F1 fuel slosh failure) Spacex has proven themselves to harbor a pretty good stable of controls engineers. I wouldn't be surprised if they could reduce parafoil CEP to the point where the ship catcher wouldn't have to move much at all (Yes, I know analysis without numbers is just an opinion, to quote another poster's byline)

Sent from my LGLS885 using Tapatalk



Look at the AI in quadcopter drones; give the latest commercially available examples a Lat/Long and they'll go there, or follow a signal. SpaceX doesn't need to re-invent the wheel, just to place a landing pad in the right place. Once the things hit the water they are probably useless anyway...
Title: Re: Fairing reuse
Post by: meekGee on 06/05/2016 03:57 AM
Or use an airplane to recover them. Doesn't have to be a helicopter. Corona used airplanes. Seems like it'd be cheaper, faster, maybe safer. Airplanes are lower maintenance, can cover a much longer range, and SpaceX already uses them sometimes just for observing the booster recovery attempts.

Once a fairing halve is caught by the plane, however, I'm not entirely sure how it'd be gently placed on the ground.

There's a trick to that.

If the line is long, and the airplane flies in a tight circle, the bottom of the line remains stationary  (so the line describes a down-vertex cone.

Title: Re: Fairing reuse
Post by: pericynthion on 06/05/2016 05:54 AM
There's a trick to that.

If the line is long, and the airplane flies in a tight circle, the bottom of the line remains stationary  (so the line describes a down-vertex cone.

Unfortunately that doesn't work well if there's any wind.  But there are some tricks you can do.
Title: Re: Fairing reuse
Post by: The Amazing Catstronaut on 06/05/2016 06:02 AM
Could it pop floatation bags and would it stay in one (well, two) piece(s) under wave action? I'm trying to think of ways a fairing half could reach the surface of the sea without being either totally inundated or lost under anything but the most ideal sea conditions, just as a counterpoint to air recovery. I'm not having very good ideas.
Title: Re: Fairing reuse
Post by: AncientU on 06/05/2016 01:44 PM
When fairings are making a controlled descent, are there any more significant (dangerous) pieces planned to fall immediately downrange of the launch site?  (Second stages obviously deorbit in the Southern Sea or elsewhere.)

Will this either begin to shrink the NOTAM restrictions, or eventually eliminate them?
Can reusable rockets eventually be launched from interior (desert SouthWest, for instance) launch sites?

This could be a driver for fairing recovery, since the cost argument seems to be weak, and production capacity is trivial to scale.  If it is just cost, then someone is planning for really cheap launches.
Title: Re: Fairing reuse
Post by: Lar on 06/05/2016 01:57 PM
This could be a driver for fairing recovery, since the cost argument seems to be weak, and production capacity is trivial to scale.  If it is just cost, then someone is planning for really cheap launches.
Weak cost argument? If fairings really cost 5M a pair and you can recover/refurbish for 30% of that steady state (long term that's a generous number I GUESS (don't know)) it's a strong argument. even if it's only 3M or so you save a time.

As for scaling capacity, there's a step function there somewhere if you're already running parts of the process 24/7, they may want to avoid the cost of duplicating most or all of the line. 

Do we have hard numbers on the production process and timings?
Title: Re: Fairing reuse
Post by: cscott on 06/05/2016 02:59 PM
AIUI the production capacity is *not* trivial to scale.  The equipment is large, a lot of manual labor is involved; you'd need to build a new factory to hold the new equipment and train a new workforce.  And those are then ongoing fixed costs you incur even when you don't happen to need the excess capacity.

SpaceX has run the spreadsheets.
Title: Re: Fairing reuse
Post by: joek on 06/05/2016 03:08 PM
...
This could be a driver for fairing recovery, since the cost argument seems to be weak, and production capacity is trivial to scale.  If it is just cost, then someone is planning for really cheap launches.

If they save $1 in all-up costs, they are ahead.  That they are seriously pursuing fairing recovery-reuse at this time suggests that it is high on the list of potential cost saving measures.
Title: Re: Fairing reuse
Post by: AncientU on 06/05/2016 04:23 PM
...
This could be a driver for fairing recovery, since the cost argument seems to be weak, and production capacity is trivial to scale.  If it is just cost, then someone is planning for really cheap launches.

If they save $1 in all-up costs, they are ahead.  That they are seriously pursuing fairing recovery-reuse at this time suggests that it is high on the list of potential cost saving measures.

I agree that the cost argument is most likely -- though I doubt they'd do all of this capability augmentation for your $1 net per launch (did you mean $1M?).  If fairing pairs are $5M as Lar speculates (my guess would be half or less of that), they would have to save a substantial portion of that to avoid locking in that $5M into the base price.  If they can save a substantial portion, say 75% or more, then baseline cost improvement is relevant.

Going back to the circa $43M price for reused booster, a couple million dollars saved on fairing recovery is less than 5%... never getting to the ultimate price range that way.  But, that said, if they see $2-3M as significant cost factor down the road, then this could actually be a harbinger of something incredible.
Title: Re: Fairing reuse
Post by: guckyfan on 06/05/2016 05:13 PM
Production capacity may not be trivial to scale. It seems they are limited in space at the Hawthorne site. They may have to transfer the whole fairing production to another location to increase capacity. They may not want to do that.

Plus Elon Musks just likes reuse as long as the cost balance is positive.
Title: Re: Fairing reuse
Post by: Lar on 06/05/2016 05:17 PM
I think they'd do it for positive 1.00 USD per fairing. Because it's a way to learn about stuff, and just because it was barely marginal on this ship, it might be hugely positive on the next one.

I don't think it's barely marginal, I think it's a big win but even if it was.... The 5M isn't from me, I read it somewhere but I forget where. I think Musk said it was in the millions...
Title: Re: Fairing reuse
Post by: MP99 on 06/05/2016 07:14 PM
For FH, which obviously stages the centre core later, could the fairing be retained on the core, and recovered as part of the core landing?

It would obviously imply a larger fairing which would also encapsulate the upper stage. Could imagine this causing various issues, including loss of commonality with F9 fairing.

Cheers, Martin
Title: Re: Fairing reuse
Post by: oiorionsbelt on 06/06/2016 12:00 AM
It appears as though the fairings end up as flotsam.
Get it in the water gently, pick it up quickly, design for salt water and see if it's any good to use again.
Title: Re: Fairing reuse
Post by: joek on 06/06/2016 03:30 AM
I agree that the cost argument is most likely -- though I doubt they'd do all of this capability augmentation for your $1 net per launch (did you mean $1M?).
...

Meant $1.00.  That SpaceX is pursuing fairing reuse at this point suggests that it is potentially low-hanging fruit.  That is, if you put recovery-reuse-cost-benefit on a Pareto chart, it would probably be near the top.  In any case, that savings from any single effort must be large in order to justify pursuit is a disease that SpaceX does not seem to be afflicted with.
Title: Re: Fairing reuse
Post by: wannamoonbase on 06/06/2016 04:58 AM
I agree that the cost argument is most likely -- though I doubt they'd do all of this capability augmentation for your $1 net per launch (did you mean $1M?).
...

Meant $1.00.  That SpaceX is pursuing fairing reuse at this point suggests that it is potentially low-hanging fruit.  That is, if you put recovery-reuse-cost-benefit on a Pareto chart, it would probably be near the top.  In any case, that savings from any single effort must be large in order to justify pursuit is a disease that SpaceX does not seem to be afflicted with.

I think it could also mean that upper stage recovery is some distance down the road.   Falcon 9 replacement type stuff.
Title: Re: Fairing reuse
Post by: S.Paulissen on 06/06/2016 05:25 AM
It could also mean they need fairings as much as they need reused cores to launch satellites.
Title: Re: Fairing reuse
Post by: Mariusuiram 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.
Title: Re: Fairing reuse
Post by: JamesH65 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.
Title: Re: Fairing reuse
Post by: Kaputnik 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.
Title: Re: Fairing reuse
Post by: rpapo 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.
Title: Re: Fairing reuse
Post by: cscott 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.
Title: Re: Fairing reuse
Post by: kevin-rf 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.
Title: Re: Fairing reuse
Post by: envy887 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?
Title: Re: Fairing reuse
Post by: Lar 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...
Title: Re: Fairing reuse
Post by: Bubbinski on 06/19/2016 02:31 AM
Did SpaceX attempt a fairing recovery on the Eutelsat/ABS mission?
Title: Re: Fairing reuse
Post by: cscott 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.
Title: Re: Fairing reuse
Post by: Adriano 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!
Title: Re: Fairing reuse
Post by: Jim 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
Title: Re: Fairing reuse
Post by: RAN 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.
Title: Re: Fairing reuse
Post by: Robotbeat 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.
Title: Re: Fairing reuse
Post by: meekGee 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! 

Title: Re: Fairing reuse
Post by: oiorionsbelt 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.
Title: Re: Fairing reuse
Post by: envy887 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.
Title: Re: Fairing reuse
Post by: DAZ 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.
Title: Re: Fairing reuse
Post by: meekGee 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.
Title: Re: Fairing reuse
Post by: envy887 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)
Title: Re: Fairing reuse
Post by: Robotbeat on 08/12/2016 11:21 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.
I take that as a compliment. :)

http://spacecraft.ssl.umd.edu/akins_laws.html
Akin's Laws of Spacecraft Design:
"36. Any run-of-the-mill engineer can design something which is elegant. A good engineer designs systems to be efficient. A great engineer designs them to be effective."
Title: Re: Fairing reuse
Post by: Nomadd on 08/13/2016 01:57 AM
 You need to stop posting these ideas in a public forum before Boeing or BO patents them all.
 (I'm for the giant ball pit landing zone myself)
Title: Re: Fairing reuse
Post by: CuddlyRocket on 08/13/2016 06:13 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! 

Why not a net? What's the terminal velocity of a fairing compared to a human?
Title: Re: Fairing reuse
Post by: envy887 on 08/13/2016 07:32 PM
Why not a net? What's the terminal velocity of a fairing compared to a human?

Musk said they were planning to try steerable chutes, so terminal velocity is probably only a few m/s. The only question is whether they are willing to splash them, use a built-in inflatables, or land them on something.

Stretching a net between two ships seems a lot harder than floating a bunch of airbags though...
Title: Re: Fairing reuse
Post by: docmordrid on 08/13/2016 09:04 PM
I'm thinking the collapsed air bag(s) will be conformal to the inside of the fairing, expanded by an N2 cylinder or chemical gas generator. Access cutouts or uncovered  positions as needed per fairing design.

Basically, large Turtle-Pacs

Perhaps the parafoil will be externally mounted and conformal under a blister fairing?
Title: Re: Fairing reuse
Post by: meekGee on 08/14/2016 06:44 AM
I'm thinking the collapsed air bag(s) will be conformal to the inside of the fairing, expanded by an N2 cylinder or chemical gas generator. Access cutouts or uncovered  positions as needed per fairing design.

Basically, large Turtle-Pacs

Perhaps the parafoil will be externally mounted and conformal under a blister fairing?

Yeah, but bouncing around in the waves, this is a large structure, and it's in two pieces that are much weaker than the whole thing.

I'm honestly baffled by all of this.  Heli recovery sounds odd because the range is so long.   Airplane recovery I can believe, but landing it is tricky. 

Hey, if the fairing is going to see salt water anyway, maybe have it sink, and hang underwater using a buoy. 

Then pick it up with a boat and a crane.
Title: Re: Fairing reuse
Post by: gregpet on 08/15/2016 03:24 AM
It would make sense that SpaceX would want the fairings to end up as close to a recovery vessel as possible.  Given the success using GPS and steering/landing 1st stage, why wouldn't SpaceX not bring fairings back to OCISLO (using steerable chutes and GPS to steer).  Maybe even try to land them on the barge somehow (after the first stage lands so timing would obviously have to work).

Given the height of release, do you have enough altitude to cove the ground (water) back to the SpaceX flotilla?   
Title: Re: Fairing reuse
Post by: Comga on 08/15/2016 03:56 AM
From over in the Missions section

(snip)


 I happened to watch the launch this morning standing next to some of the crew who work the Go Quest and Go Searcher and among other things they mentioned that they secure the rockets where they land as soon as possible and don't try to move them on deck for fear of toppling. They said the last successful one was a real handful with the bent leg.

They also said they are routinely within 5 miles of the splashdown point of the fairings and they can see them "tumbling like a leaf" before hitting the water, where they then break up. Pieces are recovered.


If they are whole and tumbling within sight one would think some moderate amount of parachute deployed at low altitude might be enough to get them into the water without breaking up.
Title: Re: Fairing reuse
Post by: meekGee on 08/15/2016 05:30 AM
It would make sense that SpaceX would want the fairings to end up as close to a recovery vessel as possible.  Given the success using GPS and steering/landing 1st stage, why wouldn't SpaceX not bring fairings back to OCISLO (using steerable chutes and GPS to steer).  Maybe even try to land them on the barge somehow (after the first stage lands so timing would obviously have to work).

Given the height of release, do you have enough altitude to cove the ground (water) back to the SpaceX flotilla?   

I'm surprised at that.  The second stage is burning for a while there before the fairings are jettisoned.  Covering more distance, and increasing velocity...

And without a lot of aerodynamics, and only, what, 10 miles of somewhat useful atmosphere - I can't see them flying back.  I'd think they need to back track 100s of miles.
Title: Re: Fairing reuse
Post by: Robotbeat on 08/15/2016 05:43 AM
There's a little more than 10 miles, but yeah. I think you could glide for about 100 miles maybe. More like 50 miles reliably.
Title: Re: Fairing reuse
Post by: envy887 on 08/15/2016 02:00 PM
For JCSAT-16, S1 sep happened at 2265 m/s velocity and ~1000 m/s change in altitude, so ~2050 m/s downrange velocity. Fairing sep happened 59 seconds later at 2500 m/s velocity and ~400 m/s change in altitude, so ~2460 m/s downrange velocity.

It shouldn't be too hard to figure the downrange distance between the fairings and the S1 as they each coast uphill after sep, but things get a lot tougher after that. To start with, the downrange distance between them at fairing sep is the average velocity of the fairing relative to the S1, multiplied by the time that it is accelerating: d_sep = (v_S1 - v_f)/2 * 59 = 12,100 m.

The S1 is coasting up for ~100 seconds to bleed off the 1,000 m/s vertical velocity at MECO. MECO is at ~65 km, so it coasts up to ~116 km at about T+253 sec. Fairing sep is at 113 km altitude with enough velocity up to coast to ~120 km about 40 seconds after sep (T+252 sec). Additional distance between the two while going uphill is 410 m/s for 40 seconds, or 16.5 km.

So the S1 and fairing end up at nearly the same apogee at almost exactly the same time, separated by about 28.5 km, but with the fairing still going downrange somewhat faster. Depending on how much faster aero drag slows the relatively light and large fairing, the S1 might actually land farther downrange than the fairings.
Title: Re: Fairing reuse
Post by: Comga on 08/15/2016 03:59 PM
For JCSAT-16, S1 sep happened at 2265 m/s velocity and ~1000 m/s change in altitude, so ~2050 m/s downrange velocity. Fairing sep happened 59 seconds later at 2500 m/s velocity and ~400 m/s change in altitude, so ~2460 m/s downrange velocity.

It shouldn't be too hard to figure the downrange distance between the fairings and the S1 as they each coast uphill after sep, but things get a lot tougher after that. To start with, the downrange distance between them at fairing sep is the average velocity of the fairing relative to the S1, multiplied by the time that it is accelerating: d_sep = (v_S1 - v_f)/2 * 59 = 12,100 m.

The S1 is coasting up for ~100 seconds to bleed off the 1,000 m/s vertical velocity at MECO. MECO is at ~65 km, so it coasts up to ~116 km at about T+253 sec. Fairing sep is at 113 km altitude with enough velocity up to coast to ~120 km about 40 seconds after sep (T+252 sec). Additional distance between the two while going uphill is 410 m/s for 40 seconds, or 16.5 km.

So the S1 and fairing end up at nearly the same apogee at almost exactly the same time, separated by about 28.5 km, but with the fairing still going downrange somewhat faster. Depending on how much faster aero drag slows the relatively light and large fairing, the S1 might actually land farther downrange than the fairings.

All well and good, but it doesn't matter.
Quote
[The recovery crew] said they are routinely within 5 miles of the splashdown point of the fairings and they can see them "tumbling like a leaf" before hitting the water, where they then break up.

I am as surprised as anyone that the fairings don't come down a hundred kilometers downrange, but they don't.
There is no need for said "50 miles" of fairing glide range, or even any controlled landing (yet). 
It seems to be not a large step to get the fairings into the water without being destroyed, so that they can be fetched whole by the recovery crew just like the "Pieces are recovered".
Title: Re: Fairing reuse
Post by: Kaputnik on 08/15/2016 04:22 PM
Is that quote from the ASDS/Elsbeth etc crew, or from the Go Searcher crew who are/were specifically looking for the fairings?
Title: Re: Fairing reuse
Post by: Hobbes-22 on 08/15/2016 05:13 PM

All well and good, but it doesn't matter.
Quote
[The recovery crew] said they are routinely within 5 miles of the splashdown point of the fairings and they can see them "tumbling like a leaf" before hitting the water, where they then break up.

I am as surprised as anyone that the fairings don't come down a hundred kilometers downrange, but they don't.
There is no need for said "50 miles" of fairing glide range, or even any controlled landing (yet). 
It seems to be not a large step to get the fairings into the water without being destroyed, so that they can be fetched whole by the recovery crew just like the "Pieces are recovered".

The first stage (when in the proper orientation for recovery) has a much higher ratio of mass vs. surface area than the fairings so it experiences much less deceleration due to drag.
Title: Re: Fairing reuse
Post by: Jcc on 08/15/2016 06:03 PM

All well and good, but it doesn't matter.
Quote
[The recovery crew] said they are routinely within 5 miles of the splashdown point of the fairings and they can see them "tumbling like a leaf" before hitting the water, where they then break up.

I am as surprised as anyone that the fairings don't come down a hundred kilometers downrange, but they don't.
There is no need for said "50 miles" of fairing glide range, or even any controlled landing (yet). 
It seems to be not a large step to get the fairings into the water without being destroyed, so that they can be fetched whole by the recovery crew just like the "Pieces are recovered".

The first stage (when in the proper orientation for recovery) has a much higher ratio of mass vs. surface area than the fairings so it experiences much less deceleration due to drag.

It's a pity SpaceX cut off the "falling back" video before it hit the atmosphere, but you can bet they know what happens to it:
https://m.youtube.com/watch?v=4_sLTe6-7SE

Apparently, it remains intact until it hits the water at terminal velocity, so a parachute would allow it to splash down intact, but I would think it much better if it never falls n saltwater.

So, my thought is to put 2 helicopters on a barge or ship with helipads, and take off at launch time, snag the fairings in mid-air, and set them back on the barge and land again on the helipads. Solves the helicopter endurance problem.
Title: Re: Fairing reuse
Post by: rickyramjet on 08/15/2016 08:38 PM

Apparently, it remains intact until it hits the water at terminal velocity, so a parachute would allow it to splash down intact, but I would think it much better if it never falls n saltwater.

So, my thought is to put 2 helicopters on a barge or ship with helipads, and take off at launch time, snag the fairings in mid-air, and set them back on the barge and land again on the helipads. Solves the helicopter endurance problem.
I think the cost of two ships, two helicopters, crew, fuel, and always on call for whenever a launch is planned would soon negate the advantage of fairing recovery.  I would also imagine trying to snag a fairing on a chute at night would be super difficult and dangerous.  Now that S1 recovery kinks are getting ironed out I think we'll soon see fairings with chutes of some kind, and a soft landing in the ocean.  Being composite it may be that salt water is not as terrible as many think. 
Title: Re: Fairing reuse
Post by: abaddon on 08/15/2016 09:09 PM
Is that quote from the ASDS/Elsbeth etc crew, or from the Go Searcher crew who are/were specifically looking for the fairings?
From the original quote up above:
Quote
next to some of the crew who work the Go Quest and Go Searcher
Title: Re: Fairing reuse
Post by: abaddon on 08/15/2016 09:10 PM
I think the cost of two ships, two helicopters, crew, fuel, and always on call for whenever a launch is planned would soon negate the advantage of fairing recovery.
The fairing costs in the "millions", I've seen the estimate of 3-5 million thrown around.  You can do a lot for that, assuming the results are worth it.

Not saying it would be easy or cheap.
Title: Re: Fairing reuse
Post by: Jcc on 08/15/2016 09:44 PM

Apparently, it remains intact until it hits the water at terminal velocity, so a parachute would allow it to splash down intact, but I would think it much better if it never falls n saltwater.

So, my thought is to put 2 helicopters on a barge or ship with helipads, and take off at launch time, snag the fairings in mid-air, and set them back on the barge and land again on the helipads. Solves the helicopter endurance problem.
I think the cost of two ships, two helicopters, crew, fuel, and always on call for whenever a launch is planned would soon negate the advantage of fairing recovery.  I would also imagine trying to snag a fairing on a chute at night would be super difficult and dangerous.  Now that S1 recovery kinks are getting ironed out I think we'll soon see fairings with chutes of some kind, and a soft landing in the ocean.  Being composite it may be that salt water is not as terrible as many think.

You may be right, we will find out. They can have gps and a radio transmitter to report their location in real time, and lights to help see them at night. That would be useful for a splashdown recovery also.
Title: Re: Fairing reuse
Post by: Comga on 08/17/2016 04:18 AM
All well and good, but it doesn't matter.
Quote
[The recovery crew] said they are routinely within 5 miles of the splashdown point of the fairings and they can see them "tumbling like a leaf" before hitting the water, where they then break up.

I am as surprised as anyone that the fairings don't come down a hundred kilometers downrange, but they don't.
There is no need for said "50 miles" of fairing glide range, or even any controlled landing (yet). 
It seems to be not a large step to get the fairings into the water without being destroyed, so that they can be fetched whole by the recovery crew just like the "Pieces are recovered".

(snip)
Apparently, it remains intact until it hits the water at terminal velocity, so a parachute would allow it to splash down intact, but I would think it much better if it never falls n saltwater.

So, my thought is to put 2 helicopters on a barge or ship with helipads, and take off at launch time, snag the fairings in mid-air, and set them back on the barge and land again on the helipads. Solves the helicopter endurance problem.

Define "better" and remember that "Better is the enemy of good enough".

We generally agreed to NOT propose mechanical solutions and wait for SpaceX to tell us what they are actually doing.

I didn't say how SpaceX could do that.  Risking violating this agreement, parachutes are a solution SpaceX has tried to use, back on Falcon 1 and the original Falcon 9.  Those boosters didn't survive reentering the atmosphere, so they never got to the point they could deploy their parachutes.  However we have reliable information from participants that this is not the case for fairings.

It still seems that the fairing halves' flight could be changed from "falling leaf" to something stable. With the right angle and reduced velocity, they could land without breaking up.  Then SpaceX can see if salt water immersion is fatal or tolerable, if it is "good enough" or if they need something "better".
Title: Re: Fairing reuse
Post by: guckyfan on 08/17/2016 07:22 AM
Then SpaceX can see if salt water immersion is fatal or tolerable, if it is "good enough" or if they need something "better".

That is the one thing I expect them to know already. It is quite easy to dump a piece into the water and get it out after a few hours. They may have a defective fairing half to do that or they produce a sheet using the same production methods.

Title: Re: Fairing reuse
Post by: vaporcobra on 08/18/2016 01:22 AM
I think the cost of two ships, two helicopters, crew, fuel, and always on call for whenever a launch is planned would soon negate the advantage of fairing recovery.
The fairing costs in the "millions", I've seen the estimate of 3-5 million thrown around.  You can do a lot for that, assuming the results are worth it.

Not saying it would be easy or cheap.

Good to remember that possibly the main motivator behind fairing recovery is the fact that fairings themselves act as a significant roadblock to even relatively minor increases in cadence, and definitely act as a hard ceiling for any serious increases in cadence. Price is very much secondary, though it is significant :)
Title: Re: Fairing reuse
Post by: vaporcobra on 08/18/2016 01:29 AM
Quote
I am as surprised as anyone that the fairings don't come down a hundred kilometers downrange, but they don't.
There is no need for said "50 miles" of fairing glide range, or even any controlled landing (yet). 
It seems to be not a large step to get the fairings into the water without being destroyed, so that they can be fetched whole by the recovery crew just like the "Pieces are recovered".

Worth noting that fairings already almost certainly have a significant level of control over their course, at least to the extent that they almost certainly already have RCS and some serious onboard avionics. They likely have a surprising amount of control over where they end up!
Title: Re: Fairing reuse
Post by: joncz on 08/18/2016 11:17 AM
Worth noting that fairings already almost certainly have a significant level of control over their course, at least to the extent that they almost certainly already have RCS and some serious onboard avionics. They likely have a surprising amount of control over where they end up!

Source for this claim?
Title: Re: Fairing reuse
Post by: The_Ronin on 08/18/2016 06:06 PM
There was footage a couple launches ago of one of the fairing halves firing RCS thrusters.
Title: Re: Fairing reuse
Post by: Comga on 08/18/2016 10:31 PM
There was footage a couple launches ago of one of the fairing halves firing RCS thrusters.

While a true statement, that does not say they "have a significant level of control over their course".
At least one fairing had RCS.  Whether that was sufficient to control its attitude and course is not known.

If it was sufficient, they would be stable in the atmosphere.  It's unlikely that SpaceX would have abandoned an effective control system, so the fact that the fairings are seen as falling like leaves means it was probably not sufficient.
Title: Re: Fairing reuse
Post by: Burninate on 08/18/2016 11:50 PM
There was footage a couple launches ago of one of the fairing halves firing RCS thrusters.

IIRC, there was footage of a gas release.  This is distinct from an RCS in goals and degree of control.  Emptying the pneumatic cylinders would just be a safety measure designed to ensure that anything which lands on the ground doesn't explode on impact with greater than kinetic energy.
Title: Re: Fairing reuse
Post by: Chris_Pi on 08/19/2016 12:25 AM
There was footage a couple launches ago of one of the fairing halves firing RCS thrusters.

While a true statement, that does not say they "have a significant level of control over their course".
At least one fairing had RCS.  Whether that was sufficient to control its attitude and course is not known.

If it was sufficient, they would be stable in the atmosphere.  It's unlikely that SpaceX would have abandoned an effective control system, so the fact that the fairings are seen as falling like leaves means it was probably not sufficient.

RCS to start, But IMHO it's unlikely to be RCS all the way down* - Earlier in this thread:
https://twitter.com/elonmusk/status/738471747540783104 (https://twitter.com/elonmusk/status/738471747540783104)

in response to a question: Are RCS thrusters the sole component for fairing recovery? Are chutes required?

Quote
@mattyteare @karaswisher @waltmossberg @YouTube autosteering chutes will be added soon

So, we'll perhaps see some fairing halves coming back under chutes!

RCS just has to keep it stable until the air is thick enough to deploy a parachute without tangling it. And probably can't do much more - Increasing forces on the fairing will chew through the gas supply pretty quick. Big enough and it could be made to work, But at some point the parachute is probably lighter than the gas bottles.

Since it sounds like they're coming down pretty close to the support ships the impact point must be pretty predictable even if they can't steer them to where they want. Pretty sure they know the ships won't take a hit from a fairing, So the return location is probably known within a couple miles or less. In one piece until impact at least suggests they don't tumble during re-entry.

I think this problem is being solved form separation on down - Control orientation, keep stable until parachutes can be used (Where things appear to be now), Then add expensive/heavy parachutes and prove they work. Soft-splashdown or midair snag last.

*It's turtles, Of course.**
** I couldn't just leave that one sitting there. Had to.

Title: Re: Fairing reuse
Post by: CraigLieb on 08/19/2016 03:38 PM
Green Goblin Glider?
 Deploy small jet engines from the back curve and steer it down using the curved shape to surf the air.
Title: Re: Fairing reuse
Post by: Comga on 08/20/2016 03:00 AM
What Chris-PI said

And it IS turtles all the way down!
Title: Re: Fairing reuse
Post by: Jet Black on 08/22/2016 08:09 AM
I think the cost of two ships, two helicopters, crew, fuel, and always on call for whenever a launch is planned would soon negate the advantage of fairing recovery.
The fairing costs in the "millions", I've seen the estimate of 3-5 million thrown around.  You can do a lot for that, assuming the results are worth it.

Not saying it would be easy or cheap.

Good to remember that possibly the main motivator behind fairing recovery is the fact that fairings themselves act as a significant roadblock to even relatively minor increases in cadence, and definitely act as a hard ceiling for any serious increases in cadence. Price is very much secondary, though it is significant :)

Given the investment interest that people have in SpaceX, but the relatively closed shop since they aren't going for IPO, I wonder whether it would be worth them starting up a public supplier company to raise the money just for that job.
Title: Re: Fairing reuse
Post by: Geron on 02/20/2017 06:23 AM
Gwynne shot well stated the fairings will be recovered this year mid air as submersion in salt water is not allowable.
Title: Re: Fairing reuse
Post by: FutureSpaceTourist on 02/20/2017 08:44 AM
Gwynne's other key quote from the 39A press conference on Friday was that they'd love to re-use fairings and maybe this year you'll see that.

Must imply some fairing recovery attempts rather sooner?
Title: Re: Fairing reuse
Post by: Jarnis on 02/20/2017 10:45 AM
Gwynne's other key quote from the 39A press conference on Friday was that they'd love to re-use fairings and maybe this year you'll see that.

Must imply some fairing recovery attempts rather sooner?

Maybe as soon as... 2 weeks  :)
Title: Re: Fairing reuse
Post by: envy887 on 02/20/2017 01:33 PM
Gwynne shot well stated the fairings will be recovered this year mid air as submersion in salt water is not allowable.

Did she specifically say airborne recovery? There are other methods of recovery that can prevent immersion.
Title: Re: Fairing reuse
Post by: Robotbeat on 02/20/2017 02:23 PM
Always important to get exact phrasing.
Title: Re: Fairing reuse
Post by: rsdavis9 on 02/20/2017 02:36 PM
All she said was "we don't want to get it wet".
Never anything about airborne or whatever(barge?).
Title: Re: Fairing reuse
Post by: dorkmo on 02/20/2017 05:10 PM
I think there was some speculation that they were outfitting one of the GO vessels for fairing recovery? Wonder if thats still on the table. Hard to imagine they could use a ship for recovery while keeping the fairings dry. Maybe they could deploy some big inflatable rafts?
Title: Re: Fairing reuse
Post by: cscott on 02/20/2017 11:36 PM
Or RTLS if they have enough cross-range.  I was listening carefully as well and @rsdavis9 has it right. "Not wet" but not specific on how that was to be done.
Title: Re: Fairing reuse
Post by: Kaputnik on 02/21/2017 01:27 PM
Any merit in a poll? Mid air recovery, support ship deck, RTLS, other?
Title: Re: Fairing reuse
Post by: rsdavis9 on 02/21/2017 01:32 PM
If I remember correctly there was already a calculation of maximum glide ratio with a parasail and the distance from launch site to location of meco occurs at and it wouldn't make it back. How about grand bahama(freeport) or abaco?

EDIT
Title: Re: Fairing reuse
Post by: wannamoonbase on 02/21/2017 02:09 PM
Any merit in a poll? Mid air recovery, support ship deck, RTLS, other?

My vote is Mid air recovery depositing the halves on a ship/barge. 
Title: Re: Fairing reuse
Post by: Lee Jay on 02/21/2017 02:30 PM
What Gwen said was, "we're going to try to bring them back"..."we would eventually love to reuse them so you got to land them not in the water".

https://www.youtube.com/watch?v=xjXYSJF-7Cs?t=13m3s
Title: Re: Fairing reuse
Post by: Daniels30 on 02/21/2017 03:42 PM
Morning/Evening All,

This is regarding the Echostar-23 GTO Mission faring recovery plans.
As this is the first Faring recovery attempt SpaceX has planned i have been thinking on what risks may occur.
Firsty there's weight of the fairing. Presumably this has some kind of heat shield much like stage 1 uses and Dragon to re enter Earth's atmosphere. (obviously not orbital speeds but still a decent amount of velocity just over 9000 Km/H on the SES-9 mission)
There's also a potential for a parachute that would be mounted inside so that's a little more weight to cope with.
What measures would the pneumatically activated fairings clamps have to change in order to achieve sufficient clearance of stage 2? Would a higher pressure charge be adequate in removing the fairings and cleaning F9 safely.
I'd appreciate any responses from folks. 
Title: Re: Fairing reuse
Post by: cscott on 02/21/2017 04:12 PM
"land" makes it sound like mid-air recovery isn't the primary focus right now; they might try to catch it with an ASDS first.  Especially for Echostar, since the ASDS won't need to catch the booster.  We should keep an eye out for the ASDS leaving port.
Title: Re: Fairing reuse
Post by: nacnud on 02/21/2017 04:21 PM
I wonder if they could be recovered in a similar way to scaneagle by flying into a wire or net.

https://www.youtube.com/watch?v=NY1Y9LBATHo
Title: Re: Fairing reuse
Post by: getitdoneinspace on 02/21/2017 08:32 PM
I wonder if they could be recovered in a similar way to scaneagle by flying into a wire or net.

That is a very interesting idea. I wonder how much time would pass between the Falcon 9 landing on the ASDS and the two fairing halves arriving at the ASDS. Keying off the "Autonomous" word, just imagine immediately after the Falcon 9 lands a simple robot autonomously secures the rocket to the deck, while at the same time, two autonomous articulating boom lift type devices move to opposite edges of the ASDS and each position themselves to snag one of the fairing halves. The parafoil (para something ?) for each fairing would need to be very accurate, but I would guess this may be easier than landing the 1st stage.  ;)
Title: Re: Fairing reuse
Post by: Kaputnik on 02/21/2017 09:04 PM
I don't suppose anybody makes a drone that could catch a fairing half?
Title: Re: Fairing reuse
Post by: IanThePineapple on 02/21/2017 09:07 PM
I don't suppose anybody makes a drone that could catch a fairing half?

You'd need a BIG drone
Title: Re: Fairing reuse
Post by: matthewkantar on 02/21/2017 09:45 PM
just imagine immediately after the Falcon 9 lands a simple robot autonomously secures the rocket to the deck, while at the same time, two autonomous articulating boom lift type devices move to opposite edges of the ASDS and each position themselves to snag one of the fairing halves.

I think it would have to be a different ship. You would not want your safely landed ship getting kerblowed by an incoming fairing half.

Matthew
Title: Re: Fairing reuse
Post by: envy887 on 02/21/2017 10:34 PM
I don't suppose anybody makes a drone that could catch a fairing half?

There are some quite large "pilot optional" aircraft.
Title: Re: Fairing reuse
Post by: TrevorMonty on 02/22/2017 01:15 AM
Midair recovery would require 2 helicopters or drones.
Title: Re: Fairing reuse
Post by: docmordrid on 02/22/2017 02:36 AM
I don't suppose anybody makes a drone that could catch a fairing half?

You'd need a BIG drone

The K-MAX UAV chopper can carry 2.6 tonnes. Used in A'stan.

https://www.youtube.com/watch?v=-4OyZZ71RqY

Title: Re: Fairing reuse
Post by: meberbs on 02/22/2017 03:58 AM
I don't suppose anybody makes a drone that could catch a fairing half?

You'd need a BIG drone

The K-MAX UAV chopper can carry 2.6 tonnes. Used in A'stan.

https://www.youtube.com/watch?v=-4OyZZ71RqY
I had actually thought about the K-MAX as well. The K-MAX is actually a regular helicopter retrofitted to act as a UAV. It is probably cheaper to by the regular version (or some other manned helicopter) than pay Lockheed to convert one to a UAV. Also, the K-MAX UAV actually is very light itself, so it may not be best at dynamically grabbing a parachuting fairing.

Some other military drones also might have the payload capacity for a fairing, but again, I think it might actually be safer to go with larger aircraft.
Title: Re: Fairing reuse
Post by: Zed_Noir on 02/22/2017 04:05 AM
Midair recovery would require 2 helicopters or drones.

Or better yet 2 V-22 Osprey VTOLs. Conventional Helos is relatively slow to transit to a parking orbit at a reasonably high altitude plus a low service ceiling and short range. IMO Helos might only get one shot per sortie to attempt a mid-air recovery of a payload fairing section. If they can be operated from a platform near the recovery site if the helos are not equipped with in-flight refueling.
Title: Re: Fairing reuse
Post by: meekGee on 02/22/2017 05:20 AM
Can they fit two helicopters on the barge?  It halves the required range, and gets rid of endurance issues, since they only take off once the clamp release.

The helicopters should probably be unmanned, since if you have people on the barge at launch time, it complicates things...
Title: Re: Fairing reuse
Post by: cscott on 02/22/2017 03:05 PM
We've been over the mid-air recovery options before. It seems you are missing Gwynne's major hint: "land".  What are the possible options that she might call "landing"?
Title: Re: Fairing reuse
Post by: rsdavis9 on 02/22/2017 03:46 PM
I think catching them on the deck of a ship is a good possibility. They shouldn't be a risk to personnel on the ship. The fairings can move and steer and the ship can move and steer.
Title: Re: Fairing reuse
Post by: Semmel on 02/22/2017 05:22 PM
I think you all miss the unspoken 'eventually' here. Why assume a full fledged recovery procedure at the first try? It would be enough to just have glidechutes or parachutes dumping the fairing into the ocean. Maybe even for multiple flight just to make sure they understand the behaviour. Only then go out with a retrieval method.

Also it seems unlikely that the barge would be considered as a landing base since it might have a rocket sitting in the middle and no personal to handle the fairing half's after dump off. Not impossible but I would consider it unlikely.
Title: Re: Fairing reuse
Post by: SDSmith on 02/22/2017 05:31 PM
I think you all miss the unspoken 'eventually' here. Why assume a full fledged recovery procedure at the first try? It would be enough to just have glidechutes or parachutes dumping the fairing into the ocean. Maybe even for multiple flight just to make sure they understand the behaviour. Only then go out with a retrieval method.

Also it seems unlikely that the barge would be considered as a landing base since it might have a rocket sitting in the middle and no personal to handle the fairing half's after dump off. Not impossible but I would consider it unlikely.
Don't forget the fairing is quite large. The height is 43' (13.1m) x 17.1 ft (5.2m). 
Title: Re: Fairing reuse
Post by: envy887 on 02/22/2017 06:05 PM
We've been over the mid-air recovery options before. It seems you are missing Gwynne's major hint: "land".  What are the possible options that she might call "landing"?

The only option I can realistically envision is a large inflatable raft set up at specified GPS coordinates, with guided parachutes dropping the fairing halves on the coordinates and thus on the raft.

The fairings under chute would be moving pretty slowly, so they aren't real dangerous and the raft could be deployed and controlled by the ASDS support ships. The chutes should have enough cross-range to set up the raft ~10 km away from where a ballistic trajectory takes the fairings, so they don't crash into the raft or support ships in the event a chute fails to open or loses control.

IIRC the support ships already stand-off from the ASDS by about 10 km, and I've seen reports that they can see the fairings falling into the ocean. So the stand-off location can't be too far away from where the ballistic trajectory takes the fairings, but far enough to not get hit.
Title: Re: Fairing reuse
Post by: nacnud on 02/22/2017 06:13 PM
Any idea of the timing? I.E. Which lands first, the rocket or the fairing?
Title: Re: Fairing reuse
Post by: envy887 on 02/22/2017 06:51 PM
Any idea of the timing? I.E. Which lands first, the rocket or the fairing?

The fairings separate later and travel a lot slower through the atmosphere, so they will arrive later than the rocket.
Title: Re: Fairing reuse
Post by: nacnud on 02/22/2017 07:31 PM
Thanks, I thought so.
* So the barge is occupied, can't land there.
* The tug has people on, can't land there.
* The fairings are huge so mid air catching would be expensive if not impossible

Depending on the flight accuracy I wonder if you could use something like this to catch them just before they hit the water. Once the fairing is aboard they could also find lunch.
Title: Re: Fairing reuse
Post by: cscott on 02/22/2017 08:13 PM
ASDS isn't occupied for Echostar 23.  So they might well start with the large unmanned barge before trying something smaller.

Someone thought the fairings might have enough cross range to make Bermuda?
Title: Re: Fairing reuse
Post by: Lars-J on 02/22/2017 08:18 PM
ASDS isn't occupied for Echostar 23.  So they might well start with the large unmanned barge before trying something smaller.

Someone thought the fairings might have enough cross range to make Bermuda?

The first attempt will likely just be to parachute them into the ocean, for analysis. Then the next time they can improve the parachute landing accuracy, and the as a final step guide the parachute to a ship or an inflated surface in the water.

Imaging this inflated thing, but larger. ;)
Title: Re: Fairing reuse
Post by: QuantumG on 02/23/2017 12:19 AM
The fairings are basically flying wings. I wouldn't be surprised if they were aiming to fly them all the way back to the launch site.
Title: Re: Fairing reuse
Post by: IanThePineapple on 02/23/2017 12:20 AM
The fairings are basically flying wings. I wouldn't be surprised if they were aiming to fly them all the way back to the launch site.

Land them on the SLF  :)
Title: Re: Fairing reuse
Post by: Kaputnik on 02/23/2017 01:18 AM
How far downrange will they be when they hit the atmosphere?
And does anyone know the airspeed velocity of an unladen payload fairing?
Title: Re: Fairing reuse
Post by: envy887 on 02/23/2017 03:21 AM
The fairings separate after the booster does and are going downrange on the same ballistic arc. They splash hundreds of miles downrange and would need insane glide ratios to RTLS.

And no, they aren't doing a powered return.

Terminal velocity will depend a lot on exactly how heavy they are and what orientation they fall in, but 20 to 30 m/s is probably a good place to start. Chutes will cut that by 50-80%, maybe more.
Title: Re: Fairing reuse
Post by: Stan-1967 on 02/23/2017 04:11 AM
How far downrange will they be when they hit the atmosphere?
And does anyone know the airspeed velocity of an unladen payload fairing?
Considering the fairings are made by RUAG Space,  we need to use the data tables for unladen European payload fairings. 
Title: Re: Fairing reuse
Post by: Lars-J on 02/23/2017 05:03 AM
How far downrange will they be when they hit the atmosphere?
And does anyone know the airspeed velocity of an unladen payload fairing?
Considering the fairings are made by RUAG Space,  we need to use the data tables for unladen European payload fairings.

SpaceX makes their own fairings, but a goog joke nonetheless.  ;D (RUAG makes the Atlas V and Ariane V fairings)
Title: Re: Fairing reuse
Post by: woods170 on 02/23/2017 07:06 AM
How far downrange will they be when they hit the atmosphere?
And does anyone know the airspeed velocity of an unladen payload fairing?
Considering the fairings are made by RUAG Space,  we need to use the data tables for unladen European payload fairings.

SpaceX makes their own fairings, but a goog joke nonetheless.  ;D (RUAG makes the Atlas V and Ariane V fairings)
Also, the SpaceX fairings are considerably more heavy than their RUAG counterparts given that the SpaceX fairings are structurally carrying the payload while the Atlas V and Ariane V fairings are not.
Title: Re: Fairing reuse
Post by: fast on 02/23/2017 07:23 AM
Also, the SpaceX fairings are considerably more heavy than their RUAG counterparts given that the SpaceX fairings are structurally carrying the payload while the Atlas V and Ariane V fairings are not.

Is it even possible?
In this case I assume payload will have to separate from second stage together with fairing :)
Title: Re: Fairing reuse
Post by: Hobbes-22 on 02/23/2017 08:14 AM
as far as I know, SpaceX use an interface ring on top of the second stage as the load-bearing element for the payload, just like everybody else?
Title: Re: Fairing reuse
Post by: cscott on 02/23/2017 12:55 PM
I think woods170 may be referring to loads during horizontal integration.
Title: Re: Fairing reuse
Post by: woods170 on 02/23/2017 01:06 PM
I think woods170 may be referring to loads during horizontal integration.
Correct.

See Jim's explanation of it here: https://forum.nasaspaceflight.com/index.php?topic=39181.msg1561918#msg1561918 (https://forum.nasaspaceflight.com/index.php?topic=39181.msg1561918#msg1561918)

And Joek's drawing of it here: https://forum.nasaspaceflight.com/index.php?topic=39181.msg1561934#msg1561934 (https://forum.nasaspaceflight.com/index.php?topic=39181.msg1561934#msg1561934)

And Jim's endorsement of Joek's drawing here: https://forum.nasaspaceflight.com/index.php?topic=39181.msg1561969#msg1561969 (https://forum.nasaspaceflight.com/index.php?topic=39181.msg1561969#msg1561969)

And this news article shows a rare image of an encapsulated payload going horizontal: https://www.noozhawk.com/noozhawk/print/falcon_9_rocket_moving_toward_nasa_launch_at_vandenberg_afb

You will notice that the payload and fairing are not held via the PAF (Payload Attachment Fitting), but via the fairing halves. Consequently, the load of the payload goes thru the fairing, not the PAF. This requires a strong fairing. Much stronger than those from RUAG et al.
Title: Re: Fairing reuse
Post by: Jim on 02/23/2017 01:06 PM
Also, the SpaceX fairings are considerably more heavy than their RUAG counterparts given that the SpaceX fairings are structurally carrying the payload while the Atlas V and Ariane V fairings are not.

Is it even possible?
In this case I assume payload will have to separate from second stage together with fairing :)

no, the adapter (with payload) stays with the second stage
Title: Re: Fairing reuse
Post by: Jim on 02/23/2017 01:08 PM
as far as I know, SpaceX use an interface ring on top of the second stage as the load-bearing element for the payload, just like everybody else?

no, there is an adapter between payload and stage, which the fairing also mates to
Title: Re: Fairing reuse
Post by: mrkmrsk on 02/23/2017 01:22 PM
And does anyone know the airspeed velocity of an unladen payload fairing?

African, or European?
Title: Re: Fairing reuse
Post by: JasonAW3 on 02/23/2017 01:45 PM
How far downrange will they be when they hit the atmosphere?
And does anyone know the airspeed velocity of an unladen payload fairing?
Considering the fairings are made by RUAG Space,  we need to use the data tables for unladen European payload fairings.

SpaceX makes their own fairings, but a goog joke nonetheless.  ;D (RUAG makes the Atlas V and Ariane V fairings)

So what's your favorite fairing color?
Title: Re: Fairing reuse
Post by: meekGee on 02/23/2017 02:28 PM
I think woods170 may be referring to loads during horizontal integration.
Correct.

See Jim's explanation of it here: https://forum.nasaspaceflight.com/index.php?topic=39181.msg1561918#msg1561918 (https://forum.nasaspaceflight.com/index.php?topic=39181.msg1561918#msg1561918)

And Joek's drawing of it here: https://forum.nasaspaceflight.com/index.php?topic=39181.msg1561934#msg1561934 (https://forum.nasaspaceflight.com/index.php?topic=39181.msg1561934#msg1561934)

And Jim's endorsement of Joek's drawing here: https://forum.nasaspaceflight.com/index.php?topic=39181.msg1561969#msg1561969 (https://forum.nasaspaceflight.com/index.php?topic=39181.msg1561969#msg1561969)

And this news article shows a rare image of an encapsulated payload going horizontal: https://www.noozhawk.com/noozhawk/print/falcon_9_rocket_moving_toward_nasa_launch_at_vandenberg_afb

You will notice that the payload and fairing are not held via the PAF (Payload Attachment Fitting), but via the fairing halves. Consequently, the load of the payload goes thru the fairing, not the PAF. This requires a strong fairing. Much stronger than those from RUAG et al.
The fairing doesn't carry the payload since it doesn't touch it.  At worst, during horizontal integration, the fairing half carries its own weight.

There was never a good explanation of why they are heavy, except perhaps the desire for them to survive reentry.
Title: Re: Fairing reuse
Post by: cscott on 02/23/2017 02:37 PM
[...]
And this news article shows a rare image of an encapsulated payload going horizontal: https://www.noozhawk.com/noozhawk/print/falcon_9_rocket_moving_toward_nasa_launch_at_vandenberg_afb

You will notice that the payload and fairing are not held via the PAF (Payload Attachment Fitting), but via the fairing halves. Consequently, the load of the payload goes thru the fairing, not the PAF. This requires a strong fairing. Much stronger than those from RUAG et al.
The fairing doesn't carry the payload since it doesn't touch it.  At worst, during horizontal integration, the fairing half carries its own weight.

There was never a good explanation of why they are heavy, except perhaps the desire for them to survive reentry.
This photo posted above by @woods170 is pretty definitive. The fairing is carrying the weight of the payload.
Title: Re: Fairing reuse
Post by: woods170 on 02/23/2017 02:43 PM
I think woods170 may be referring to loads during horizontal integration.
Correct.

See Jim's explanation of it here: https://forum.nasaspaceflight.com/index.php?topic=39181.msg1561918#msg1561918 (https://forum.nasaspaceflight.com/index.php?topic=39181.msg1561918#msg1561918)

And Joek's drawing of it here: https://forum.nasaspaceflight.com/index.php?topic=39181.msg1561934#msg1561934 (https://forum.nasaspaceflight.com/index.php?topic=39181.msg1561934#msg1561934)

And Jim's endorsement of Joek's drawing here: https://forum.nasaspaceflight.com/index.php?topic=39181.msg1561969#msg1561969 (https://forum.nasaspaceflight.com/index.php?topic=39181.msg1561969#msg1561969)

And this news article shows a rare image of an encapsulated payload going horizontal: https://www.noozhawk.com/noozhawk/print/falcon_9_rocket_moving_toward_nasa_launch_at_vandenberg_afb (https://www.noozhawk.com/noozhawk/print/falcon_9_rocket_moving_toward_nasa_launch_at_vandenberg_afb)

You will notice that the payload and fairing are not held via the PAF (Payload Attachment Fitting), but via the fairing halves. Consequently, the load of the payload goes thru the fairing, not the PAF. This requires a strong fairing. Much stronger than those from RUAG et al.
The fairing doesn't carry the payload since it doesn't touch it.  At worst, during horizontal integration, the fairing half carries its own weight.

There was never a good explanation of why they are heavy, except perhaps the desire for them to survive reentry.
Did you bother to read the referenced posts from Jim and Joek?
The payload is attached to the PAF and the PAF is attached to the bottom of the fairing halves. However, SpaceX does not handle this entire assembly by grabbing hold of the (bottom of the) PAF, but by grabbing the fairing itself. Thus, the load exerted by the payload goes thru the fairing. This applies for all ground-handling sequences once the payload is encapsulated. Lifting, break-over to horizontal, lifting for mating with the launch vehicle. All those are done by grabbing the fairing, not the PAF.

Only times the PAF carries the payload are while vertical, and the PAF is sitting on either the encapsulation fixture or on top of the erected rocket. But in all break-over and horizontal operations the payload is carried by the fairing, via the PAF.
Title: Re: Fairing reuse
Post by: rsdavis9 on 02/23/2017 02:49 PM
But to be perfectly clear... :)

When the fairing is supported the load of the payload goes through the PAF and then to the fairing.
There is no direct connection between the payload and fairing.

Correct?
Title: Re: Fairing reuse
Post by: woods170 on 02/23/2017 02:52 PM
But to be perfectly clear... :)

When the fairing is supported the load of the payload goes through the PAF and then to the fairing.
There is no direct connection between the payload and fairing.

Correct?
Correct. See drawing from Joek below. It makes this perfectly clear. No direct connection between fairing and payload. Loadpath (indicated as red line in Joek's drawing) is from payload to PAF to fairing. Hoisting points are on the fairing only. Not on the PAF. So, in any hoisting operation of the encapsulated payload, the load of the payload goes thru the fairing, via the PAF.
Title: Re: Fairing reuse
Post by: Lee Jay on 02/23/2017 02:53 PM
There was never a good explanation of why they are heavy, except perhaps the desire for them to survive reentry.

Surviving the transition to supersonic and max-q are the reasons.  The thing is really large (it would easily swallow most people's entire living room), and max-q is a lot of force distributed over a lot of area.
Title: Re: Fairing reuse
Post by: woods170 on 02/23/2017 02:58 PM
There was never a good explanation of why they are heavy, except perhaps the desire for them to survive reentry.

Surviving the transition to supersonic and max-q are the reasons.  The thing is really large (it would easily swallow most people's entire living room), and max-q is a lot of force distributed over a lot of area.
No, not the real reason. Same forces apply to fairings from RUAG and other manufacturers. But those fairings are much lighter (mass-wise). Those fairings do not have to carry the payload mass during ground handling. Atlas 5 (for example) grabs the encapsulated payload via the PAF, not the fairing. Ariane 5 first has the PAF and payload integrated on the rocket, then places the fairing over them. Hence, those fairings only need to be strong enough to carry their own weight, unlike the F9 fairing.
Title: Re: Fairing reuse
Post by: cscott on 02/23/2017 03:54 PM
Granted, we haven't answered meekgee's "why" question yet.  Presumably at some early phase of design, SpaceX could have chosen to have hold the encapsulated payload by the PAF during horizontal processing. There would be a lot of cantilever forces, but I'd sure it would be technically possible.  They must have done some trade-off and determined that beefing up the payload fairing to carry the loads was worth it.  It is *possible* that thoughts about future reuse mechanisms for the fairing played some role in that decision.

IE, the "why" might be, "greatly simplifies handling during horizontal integration and the added structure can do double duty if we succeed in our reuse plans."  Much like with the sizing of the F9 first stage or the use of common fuels for S1 and S2, SpaceX appears not averse to giving up some performance (due extra fairing weight in this case) if it serves their bigger picture goals of streamlined manufacturing, rapid turnaround, and reuse.

But that's just speculation.
Title: Re: Fairing reuse
Post by: Semmel on 02/23/2017 04:06 PM
How do you mate an incapsulated payload fairing assembly with the second stage horizontally when you cannot grab the fairing? The only attachment points for the adapter is at the mating surface. I don't see how that can be done without adding a lot of mass to the adapter assembly. Remember, the heavy fairing gets off the rocket shortly after stage separation while the mass on the adapter goes to orbit. Maybe the reason the second stage including the adapter are so light is because the fairing is so heavy.

Also shines new light on the payload restrictions of about 10 T to the current payload. It was speculated that FH can not bring heavy payloads to LEO because the adapter is not capable to hold heavy loads. Maybe the adapter is not the limitation.. Maybe it's the fairing.
Title: Re: Fairing reuse
Post by: meekGee on 02/23/2017 06:14 PM
There was never a good explanation of why they are heavy, except perhaps the desire for them to survive reentry.

Surviving the transition to supersonic and max-q are the reasons.  The thing is really large (it would easily swallow most people's entire living room), and max-q is a lot of force distributed over a lot of area.

Yup. The diagram above is what I understand too.

My comments were regarding a) the payload not directly contact the fairing, and b) the fairing only holding the payload, while fully assembled, through the payload ring. (as shown).

In that case, the loading seems to me very similar to what a fairing normally experiences, or even more benign.

A closed fairing, while held at the payload ring, experiences (at the ring), torque to counteract:
- Its own mass, times any transverse acceleration during launch  (applied at the cg of the fairing)
- The aerodynamic pressure, sometimes while flying at an angle.  (applied closer to the tip of the fairing)

In the processing configuration, on the cart, it experience (at the ring), torque to counteract:
- The mass of the payload times the payload moment arm.

FWIW, if maxQ is about 30 kPa, and the fairing were to present an area of 15 m2 to the wind, that's 45 tons of force.

If transverse vibrations are, oh, 4 g max, then just the inertia of the fairing would add 16 tons, sideways.

Meanwhile, the whole satellite weighs, what, 4-5 tons?

So clearly the problem can't be at the ring.

What's left is the "eggshell", but if that was a problem, the cart would simply have a larger cradle - much easier than making the whole fairing 2x heavy just so the cradle can remain thin.


Long story short - I don't think it's the payload weight during handling.

I think a much likelier explanation is that the fairing has to take aerodynamic loads, WHILE IN TWO HALVES, during re-entry.  The half-fairing is a very weak physical structure compared to a closed fairing, and I think it the main reason for the extra mass.
Title: Re: Fairing reuse
Post by: Jim on 02/23/2017 06:18 PM
In that case, the loading seems to me very similar to what a fairing normally experiences, or even more benign.


It is nowhere near the same. On most other vehicles, the fairing never sees any loads from the payload. They could not be used in the same

Title: Re: Fairing reuse
Post by: meekGee on 02/23/2017 06:28 PM
In that case, the loading seems to me very similar to what a fairing normally experiences, or even more benign.


It is nowhere near the same. On most other vehicles, the fairing never sees any loads from the payload. They could not be used in the same

Just a matter of distributing the loads.  SpaceX clearly designed for this, but it shouldn't double the mass of the fairing.  Worst case they'd have added a ribbed structure from the support point to the payload ring, which would not weight multiple tons.  (And I don't think they needed to do that either).

What makes the SpaceX fairing twice as heavy as other fairings has to be a fairing-wide issue, and the only thing that fits the bill is either incompetence (they don't know how to build a lightweight fairing) or some unique aerodynamic requirements - and the second option is staring us right in the face, since we know they're trying recovery.


Title: Re: Fairing reuse
Post by: Jim on 02/23/2017 06:37 PM

FWIW, if maxQ is about 30 kPa, and the fairing were to present an area of 15 m2 to the wind, that's 45 tons of force.


That is an axial load and not the same as a side load
Title: Re: Fairing reuse
Post by: meekGee on 02/23/2017 06:40 PM

FWIW, if maxQ is about 30 kPa, and the fairing were to present an area of 15 m2 to the wind, that's 45 tons of force.


That is an axial load and not the same as a side load

True, but the rocket is designed to fly with an angle of attack, so there's a sideways component.  even 10% of 45 tons is comparable to the satellite, and that's on top of the dynamic loads.

Also - the moment arm is longer probably about twice of where the satellite CG is.
Title: Re: Fairing reuse
Post by: meberbs on 02/23/2017 06:43 PM
In that case, the loading seems to me very similar to what a fairing normally experiences, or even more benign.


It is nowhere near the same. On most other vehicles, the fairing never sees any loads from the payload. They could not be used in the same

Just a matter of distributing the loads.  SpaceX clearly designed for this, but it shouldn't double the mass of the fairing.  Worst case they'd have added a ribbed structure from the support point to the payload ring, which would not weight multiple tons.  (And I don't think they needed to do that either).

What makes the SpaceX fairing twice as heavy as other fairings has to be a fairing-wide issue, and the only thing that fits the bill is either incompetence (they don't know how to build a lightweight fairing) or some unique aerodynamic requirements - and the second option is staring us right in the face, since we know they're trying recovery.
Or a structural requirement. The pictures clearly show the fairing with enclosed payload being lifted by the middle of the fairing. From other's comments here, such an operation never happens with fairings for other rockets. SpaceX probably does this for some reason based on their processing flow (maybe not having to have special equipment to deal with the torque on the payload adapter before the adapter gets attached to the rocket.)

Aerodynamic concerns for recovery don't make sense, because information relating to fairing recovery has indicated that the current fairings were not designed for recovery. The current fairings were designed long before they would have been ready to seriously consider fairing recovery.

Also, you are really, really oversimplifying structural analysis in some of your posts.
Title: Re: Fairing reuse
Post by: meekGee on 02/23/2017 06:50 PM
In that case, the loading seems to me very similar to what a fairing normally experiences, or even more benign.


It is nowhere near the same. On most other vehicles, the fairing never sees any loads from the payload. They could not be used in the same

Just a matter of distributing the loads.  SpaceX clearly designed for this, but it shouldn't double the mass of the fairing.  Worst case they'd have added a ribbed structure from the support point to the payload ring, which would not weight multiple tons.  (And I don't think they needed to do that either).

What makes the SpaceX fairing twice as heavy as other fairings has to be a fairing-wide issue, and the only thing that fits the bill is either incompetence (they don't know how to build a lightweight fairing) or some unique aerodynamic requirements - and the second option is staring us right in the face, since we know they're trying recovery.
Or a structural requirement. The pictures clearly show the fairing with enclosed payload being lifted by the middle of the fairing. From other's comments here, such an operation never happens with fairings for other rockets. SpaceX probably does this for some reason based on their processing flow (maybe not having to have special equipment to deal with the torque on the payload adapter before the adapter gets attached to the rocket.)

Aerodynamic concerns for recovery don't make sense, because information relating to fairing recovery has indicated that the current fairings were not designed for recovery. The current fairings were designed long before they would have been ready to seriously consider fairing recovery.

Also, you are really, really oversimplifying structural analysis in some of your posts.

Of course I am...   I also don't have the details of their structure necessary to even start a more complex analysis....   But neither do the other posters...

All I'm saying is that the extra weight of the fairing (twice what a normal fairing would weigh) seems excessive for  the support outlined, since IMO at the worse case it would have been a small penalty, or more likely, none at all.

OTOH, those fairings are doing something else very differently from regular fairings.... trying to perform controlled re-entry...  so that should be the likely suspect.

As for when did SpaceX start thinking about fairing recovery - I don't know, and neither do you.  It's clearly not the final design, but whether they were built more robustly to enable even initial experimentation - we simply can't tell.  But probably earlier than a year ago...
Title: Re: Fairing reuse
Post by: Jim on 02/23/2017 06:53 PM

As for when did SpaceX start thinking about fairing recovery - I don't know, and neither do you.  It's clearly not the final design, but whether they were built more robustly to enable even initial experimentation - we simply can't tell.  But probably earlier than a year ago...


The fairing design predates the first launch
Title: Re: Fairing reuse
Post by: meekGee on 02/23/2017 07:36 PM

As for when did SpaceX start thinking about fairing recovery - I don't know, and neither do you.  It's clearly not the final design, but whether they were built more robustly to enable even initial experimentation - we simply can't tell.  But probably earlier than a year ago...


The fairing design predates the first launch

Why would that support your case?
Title: Re: Fairing reuse
Post by: Zed_Noir on 02/23/2017 08:02 PM
....

Also shines new light on the payload restrictions of about 10 T to the current payload. It was speculated that FH can not bring heavy payloads to LEO because the adapter is not capable to hold heavy loads. Maybe the adapter is not the limitation.. Maybe it's the fairing.

It will be interesting to see what the maximum payload will be for the FH when vertically integrated at LC-39A
Title: Re: Fairing reuse
Post by: Jim on 02/24/2017 02:06 AM

As for when did SpaceX start thinking about fairing recovery - I don't know, and neither do you.  It's clearly not the final design, but whether they were built more robustly to enable even initial experimentation - we simply can't tell.  But probably earlier than a year ago...


The fairing design predates the first launch

Why would that support your case?

because nothing supports yours and the fairing supports the payload and that it why it is heavy.  There is no other US fairing that can support a payload in the same manner without major redesign.
Title: Re: Fairing reuse
Post by: meekGee on 02/24/2017 02:08 AM

As for when did SpaceX start thinking about fairing recovery - I don't know, and neither do you.  It's clearly not the final design, but whether they were built more robustly to enable even initial experimentation - we simply can't tell.  But probably earlier than a year ago...


The fairing design predates the first launch

Why would that support your case?

because nothing supports yours and the fairing supports the payload and that it why it is heavy.  There is no other US fairing that can support a payload.
What I asked was why would the fact that the fairing design is old support your assertion.  You brought it up, not me.
Title: Re: Fairing reuse
Post by: Jim on 02/24/2017 02:08 AM
....

Also shines new light on the payload restrictions of about 10 T to the current payload. It was speculated that FH can not bring heavy payloads to LEO because the adapter is not capable to hold heavy loads. Maybe the adapter is not the limitation.. Maybe it's the fairing.

It will be interesting to see what the maximum payload will be for the FH when vertically integrated at LC-39A

if it happens at all.
Title: Re: Fairing reuse
Post by: Semmel on 02/24/2017 11:50 AM
....

Also shines new light on the payload restrictions of about 10 T to the current payload. It was speculated that FH can not bring heavy payloads to LEO because the adapter is not capable to hold heavy loads. Maybe the adapter is not the limitation.. Maybe it's the fairing.

It will be interesting to see what the maximum payload will be for the FH when vertically integrated at LC-39A

if it happens at all.

True. The primary customer for FH would be heavy GTO sats. These are not so heavy to exceed the GTO capacity of FH. So there would be no reason to update to vertical integration or new fairings that support heavier loads. Time will tell if SpaceX wants to launch heavy LEO payloads like bigelow modules and national security payloads.
Title: Re: Fairing reuse
Post by: watermod on 02/24/2017 12:59 PM
If it can be made/machined to size this new material (metal foam) might make a great next-gen faring.
http://www.foxnews.com/tech/2017/02/23/this-foam-stops-bullets-cold-and-pulverizes-them-to-dust.html (http://www.foxnews.com/tech/2017/02/23/this-foam-stops-bullets-cold-and-pulverizes-them-to-dust.html)
Title: Re: Fairing reuse
Post by: Doesitfloat on 02/24/2017 03:04 PM
This theory hasn't been mentioned yet so:
Spacex fairing are heavier because they use a less expensive but lower strength carbon fiber. The high strength aerospace carbon fiber is double to triple the cost of a utility strength fiber. In addition to ensure the higher strength the resin system is also more expensive. ( Resin system + manufacturing system)
Simply to get an equivalent strength out of lower strength fiber  there must be more... hence heavier.
But Cheaper
Title: Re: Fairing reuse
Post by: ennisj on 02/24/2017 07:15 PM
One other thing I haven't seen mentioned is that SpaceX uses a pneumatic system for fairing separation; everyone else (to my knowledge) uses pyrotechnics.

I can't imaging why that would double the weight though. But it is another difference.
Title: Re: Fairing reuse
Post by: AAPSkylab on 02/24/2017 07:34 PM
This theory hasn't been mentioned yet so:
Spacex fairing are heavier because they use a less expensive but lower strength carbon fiber. The high strength aerospace carbon fiber is double to triple the cost of a utility strength fiber. In addition to ensure the higher strength the resin system is also more expensive. ( Resin system + manufacturing system)
Simply to get an equivalent strength out of lower strength fiber  there must be more... hence heavier.
But Cheaper

Is this cheaper construction known as fact or is it speculation?

If this is true, could this mean that their intent is to research and develop fairing recovery and reuse while using this less expensive construction method.  After they succeed (if possible) then they could transfer their recovery tech to a more expensive but lighter construction method.  This way the recovery tech might not be a weight penalty and the ability to recover and reuse would mitigate the increased cost of construction.
Title: Re: Fairing reuse
Post by: Lar on 02/24/2017 08:02 PM
I like the idea that they built a cheap but heavy fairing .... knowing that eventually they would reengineer it with more expensive but lighter materials... more expensive ONCE, yes,  but since now it's recoverable (the mass savings is used for whatever the recovery mechanism is), actually LESS expensive iff they mostly get it back.

they were thinking ahead.

People focus on SpaceX changing plans but they miss that they also have been taking the long view here for a long time.

Also I don't see the need for a lot of heat shielding (said upthread a lot).... These have very low density so terminal velocity is low.
Title: Re: Fairing reuse
Post by: cscott on 02/24/2017 11:28 PM
I don't see any evidence they are using anything other than current state-of-the-art aerospace composites for the fairing.  Let's not pile speculation on speculation.
Title: Re: Fairing reuse
Post by: Lee Jay on 02/25/2017 12:20 AM
I like the idea that they built a cheap but heavy fairing ....

What makes you think it's cheap?  Elon said it was "millions of dollars", which is quite a lot for a structure this size.
Title: Re: Fairing reuse
Post by: JamesH65 on 02/25/2017 05:24 PM
I don't see any evidence they are using anything other than current state-of-the-art aerospace composites for the fairing.  Let's not pile speculation on speculation.

Of course, there is no evidence they are using state of the art aerospace composites either...unless you want to assume/speculate that they are....;-)
Title: Re: Fairing reuse
Post by: cscott on 02/25/2017 06:27 PM
We know the original manufacturer of the fairings was doing current aerospace grade work.  You can speculate that SpaceX simplified or complexified things after they brought manufacturing in-house, but until they do a major fairing redesign Occam's razor would state they are still using something close to standard manufacturing practice for composites.

And SpaceX disclaims any craziness:
Quote
. The fairing is 13.1 meters (43 feet) high and 5.2 meters (17 feet) wide. It consists of an aluminum honeycomb core with carbon-fiber face sheets fabricated in two half-shells.
http://www.spacex.com/news/2013/04/12/fairing

Note: when I say "state-of-the-art" I mean, same as any other current manufacturer would use.  I'm not claiming super secret sauce or unicorn novelty.
Title: Re: Fairing reuse
Post by: Robotbeat on 02/25/2017 06:33 PM
Toray makes the best carbon fiber, bar none. They got a monopoly on the best stuff. But it's very, very difficult to get ahold of it if you aren't Boeing. You need an agreement with them, which SpaceX only recently got. Safe to say SpaceX has not been using Toray in the past.
Title: Re: Fairing reuse
Post by: DOCinCT on 02/25/2017 08:47 PM
Even though the fairing is somewhat constrained in terms of usable volume there are spaces available not normally assigned to payload as shown in the hatched area in the picture. If they went the parachute route, the spaces by the PAF seem most useful.
(Note:the heavy PAF can handle payloads up to 24,000 lb, far short of the FH throw wgt.)
Title: Re: Fairing reuse
Post by: Jim on 02/25/2017 11:23 PM
Fairing 2.0 will be a little different and slightly larger
Title: Re: Fairing reuse
Post by: Jcc on 02/25/2017 11:31 PM
Fairing 2.0 will be a little different and slightly larger

Do you have a source (and if so, please tell)?
Title: Re: Fairing reuse
Post by: cscott on 02/26/2017 12:43 AM
Jim is a source.
Title: Re: Fairing reuse
Post by: meekGee on 02/26/2017 12:50 AM
It'll be interesting to see how much it will weigh...

Though the principle of "performance loss for reusability" still applies.
Title: Re: Fairing reuse
Post by: envy887 on 02/26/2017 01:16 AM
Any idea when this will be flying? Only on Heavy or on F9 also?
Title: Re: Fairing reuse
Post by: Jim on 02/26/2017 01:27 AM

Though the principle of "performance loss for reusability" still applies.

The current fairing existed before thoughts of such
Title: Re: Fairing reuse
Post by: Jim on 02/26/2017 01:28 AM
Any idea when this will be flying? Only on Heavy or on F9 also?

there isn't going to be a different fairing for the heavy
Title: Re: Fairing reuse
Post by: Lar on 02/26/2017 01:31 AM
I like the idea that they built a cheap but heavy fairing ....

What makes you think it's cheap?  Elon said it was "millions of dollars", which is quite a lot for a structure this size.

two things....

1) it's an idea which I like but it's not necessarily my idea, I just like it. So ask the originator.
2) cheap is a relative term. If they aren't using buckyballs in it, or unobtanium or whatever, it's cheaper than if they were.

Any idea when this will be flying? Only on Heavy or on F9 also?

there isn't going to be a different fairing for the heavy

Which I guess means that FH will be volume limited in many cases before it is mass limited?
Title: Re: Fairing reuse
Post by: cppetrie on 02/26/2017 02:03 AM
In that case, the loading seems to me very similar to what a fairing normally experiences, or even more benign.


It is nowhere near the same. On most other vehicles, the fairing never sees any loads from the payload. They could not be used in the same

Just a matter of distributing the loads.  SpaceX clearly designed for this, but it shouldn't double the mass of the fairing.  Worst case they'd have added a ribbed structure from the support point to the payload ring, which would not weight multiple tons.  (And I don't think they needed to do that either).

What makes the SpaceX fairing twice as heavy as other fairings has to be a fairing-wide issue, and the only thing that fits the bill is either incompetence (they don't know how to build a lightweight fairing) or some unique aerodynamic requirements - and the second option is staring us right in the face, since we know they're trying recovery.
Or a structural requirement. The pictures clearly show the fairing with enclosed payload being lifted by the middle of the fairing. From other's comments here, such an operation never happens with fairings for other rockets. SpaceX probably does this for some reason based on their processing flow (maybe not having to have special equipment to deal with the torque on the payload adapter before the adapter gets attached to the rocket.)

Aerodynamic concerns for recovery don't make sense, because information relating to fairing recovery has indicated that the current fairings were not designed for recovery. The current fairings were designed long before they would have been ready to seriously consider fairing recovery.

Also, you are really, really oversimplifying structural analysis in some of your posts.

Of course I am...   I also don't have the details of their structure necessary to even start a more complex analysis....   But neither do the other posters...

All I'm saying is that the extra weight of the fairing (twice what a normal fairing would weigh) seems excessive for  the support outlined, since IMO at the worse case it would have been a small penalty, or more likely, none at all.

OTOH, those fairings are doing something else very differently from regular fairings.... trying to perform controlled re-entry...  so that should be the likely suspect.

As for when did SpaceX start thinking about fairing recovery - I don't know, and neither do you.  It's clearly not the final design, but whether they were built more robustly to enable even initial experimentation - we simply can't tell.  But probably earlier than a year ago...

First post to NSF so forgive the likely uninformed intrusion on a long-running discussion, but what if the reasoning for the heavier fairing design was as follows: by integrating structural support for the payload during launch and MaxQ into the fairing rather than the payload adapter it allows them to jettison the weight of said support when fairing separation occurs meaning less weight is riding on stage 2 afterwards. If all the support is in the payload adapter, then you haul that and it's extra weight all the way out to your destination. Does the SpaceX fairing design allow a lighter payload adapter that is consequently lighter. I've not seen anything in the discussions I've visited thus far indicating one way or the other. Anyone with some insight that can chime in on the hypothesis I put forward?


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Title: Re: Fairing reuse
Post by: woods170 on 02/26/2017 10:22 AM
First post to NSF so forgive the likely uninformed intrusion on a long-running discussion, but what if the reasoning for the heavier fairing design was as follows: by integrating structural support for the payload during launch and MaxQ into the fairing rather than the payload adapter it allows them to jettison the weight of said support when fairing separation occurs meaning less weight is riding on stage 2 afterwards. If all the support is in the payload adapter, then you haul that and it's extra weight all the way out to your destination. Does the SpaceX fairing design allow a lighter payload adapter that is consequently lighter. I've not seen anything in the discussions I've visited thus far indicating one way or the other. Anyone with some insight that can chime in on the hypothesis I put forward?


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Welcome to the forum.
The fairing only supports the payload, via the PAF, during ground handling: rotation from vertical to horizontal, any horizontal handling and horizontal integration onto the rocket. Payload mass throughout launch and MaxQ is supported by the upper stage, via the PAF.
Title: Re: Fairing reuse
Post by: DOCinCT on 02/26/2017 02:59 PM
...Does the SpaceX fairing design allow a lighter payload adapter that is consequently lighter. I've not seen anything in the discussions I've visited thus far indicating one way or the other. Anyone with some insight that can chime in on the hypothesis I put forward?
Sent from my iPhone using Tapatalk
The Payload Adapter Fitting (PAF) comes in two standard versions: the light PAF payloads weighing up to 3,453 kg (7,612 lb), and  the heavy PAF up to 10,886 kg (24,000 lb). 
Title: Re: Fairing reuse
Post by: cppetrie on 02/26/2017 05:09 PM
...Does the SpaceX fairing design allow a lighter payload adapter that is consequently lighter. I've not seen anything in the discussions I've visited thus far indicating one way or the other. Anyone with some insight that can chime in on the hypothesis I put forward?
Sent from my iPhone using Tapatalk
The Payload Adapter Fitting (PAF) comes in two standard versions: the light PAF payloads weighing up to 3,453 kg (7,612 lb), and  the heavy PAF up to 10,886 kg (24,000 lb).

Those are the weight limits for PAFs, but how do the weights of the PAFs themselves compare to PAFs of other launch vehicles with similar weight capacities?


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Title: Re: Fairing reuse
Post by: cppetrie on 02/26/2017 05:14 PM
First post to NSF so forgive the likely uninformed intrusion on a long-running discussion, but what if the reasoning for the heavier fairing design was as follows: by integrating structural support for the payload during launch and MaxQ into the fairing rather than the payload adapter it allows them to jettison the weight of said support when fairing separation occurs meaning less weight is riding on stage 2 afterwards. If all the support is in the payload adapter, then you haul that and it's extra weight all the way out to your destination. Does the SpaceX fairing design allow a lighter payload adapter that is consequently lighter. I've not seen anything in the discussions I've visited thus far indicating one way or the other. Anyone with some insight that can chime in on the hypothesis I put forward?


Sent from my iPhone using Tapatalk
Welcome to the forum.
The fairing only supports the payload, via the PAF, during ground handling: rotation from vertical to horizontal, any horizontal handling and horizontal integration onto the rocket. Payload mass throughout launch and MaxQ is supported by the upper stage, via the PAF.

That would seems to disprove my hypothesis. Are other launch vehicles with lighter fairings only vertically integrated? Could SpaceX have made a compromise on fairing weight in order to permit horizontal integration rather than vertical? Is there an advantage in terms of rocket design or launch prep to be able to integrate horizontally?


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Title: Re: Fairing reuse
Post by: envy887 on 02/26/2017 07:38 PM
Any idea when this will be flying? Only on Heavy or on F9 also?

there isn't going to be a different fairing for the heavy

Is it related to one of the upcoming F9 blocks?
Title: Re: Fairing reuse
Post by: RoboGoofers on 03/15/2017 03:50 PM
[...]
And this news article shows a rare image of an encapsulated payload going horizontal: https://www.noozhawk.com/noozhawk/print/falcon_9_rocket_moving_toward_nasa_launch_at_vandenberg_afb

You will notice that the payload and fairing are not held via the PAF (Payload Attachment Fitting), but via the fairing halves. Consequently, the load of the payload goes thru the fairing, not the PAF. This requires a strong fairing. Much stronger than those from RUAG et al.
The fairing doesn't carry the payload since it doesn't touch it.  At worst, during horizontal integration, the fairing half carries its own weight.

There was never a good explanation of why they are heavy, except perhaps the desire for them to survive reentry.
This photo posted above by @woods170 is pretty definitive. The fairing is carrying the weight of the payload.

Are the payloads designed to be positioned with a specific CG inside the fairing? The picture shows it perfectly balanced, but the lift points don't look repositionable, so it's not clear how they deal with different payload sizes and masses. Maybe they add ballast to 'even out the scales'?
Title: Re: Fairing reuse
Post by: Jim on 03/15/2017 03:54 PM

Are the payloads designed to be positioned with a specific CG inside the fairing? The picture shows it perfectly balanced, but the lift points don't look repositionable, so it's not clear how they deal with different payload sizes and masses. Maybe they add ballast to 'even out the scales'?

There are two cranes in use.  One is attached to the aft of the fairing.
Title: Re: Fairing reuse
Post by: RoboGoofers on 03/15/2017 05:00 PM

Are the payloads designed to be positioned with a specific CG inside the fairing? The picture shows it perfectly balanced, but the lift points don't look repositionable, so it's not clear how they deal with different payload sizes and masses. Maybe they add ballast to 'even out the scales'?

There are two cranes in use.  One is attached to the aft of the fairing.

Ok I see it now. I guess it's those spiderweb-y looking lines, and maybe that blue square.

Regarding mid-air capture; has anything as large as a F9 fairing been caught mid-air before? I'd imagine its shape would make it whip around a lot behind a plane or below a helicopter.
Title: Re: Fairing reuse
Post by: Alastor on 03/15/2017 09:05 PM
Some helicopter pilots on the forum have estimated that it would be a delicate operation, but possible.
Their main concern is actually the range of the helicopters.

As for slowing down the fairing, it's a matter of flying in formation with it, grab it and then slowly enough decelerate it. As for the weight itself, there are some pretty heavy lift helicopters around. That shouldn't be a problem in itself.
Title: Re: Fairing reuse
Post by: IanThePineapple on 03/15/2017 09:12 PM
The fact that CCAFS is an air force base should fare well for helicopters catching fairings
Title: Re: Fairing reuse
Post by: leetdan on 03/15/2017 09:21 PM
The fact that CCAFS is an air force base should fare well for helicopters catching fairings

Specifically, CCAFS and the 920th Rescue Wing (HC-130P, HH-60G) are both headquartered at nearby Patrick AFB.
Title: Re: Fairing reuse
Post by: mme on 03/15/2017 09:41 PM
The fact that CCAFS is an air force base should fare well for helicopters catching fairings

Specifically, CCAFS and the 920th Rescue Wing (HC-130P, HH-60G) are both headquartered at nearby Patrick AFB.
Yeah, but it's not like SpaceX is going to use military assets to recover fairings.
Title: Re: Fairing reuse
Post by: Kaputnik on 03/15/2017 09:58 PM
Range does seem to be the killer for helicopter recovery.
I guess you could snag the fairing halves using a fixed wing, then tow them back home, release and catch with a chopper. A bit Rube Goldberg though...
Title: Re: Fairing reuse
Post by: manoweb on 03/15/2017 10:38 PM
Honestly I would be very surprised if SpaceX wants to recover the fairings, for the sole purpose of saving money, by catching them on the fly with (military) helicopters. In my opinion they will come out with something much less expensive, even if it will take some time to develop the technology to do so
Title: Re: Fairing reuse
Post by: Jim on 03/16/2017 02:15 AM
The fact that CCAFS is an air force base should fare well for helicopters catching fairings

It has no bearing on the matter.
Title: Re: Fairing reuse
Post by: Hobbes-22 on 03/16/2017 08:33 AM
Honestly I would be very surprised if SpaceX wants to recover the fairings, for the sole purpose of saving money, by catching them on the fly with (military) helicopters. In my opinion they will come out with something much less expensive, even if it will take some time to develop the technology to do so

A helicopter capable of lifting the fairing can be rented for a few thousand/hour. Not cheap, but not prohibitively expensive either if the potential savings is $2M.
Title: Re: Fairing reuse
Post by: D_Dom on 03/16/2017 03:15 PM
Lifting the fairing does not seem to me nearly as challenging as catching one on the fly.
Title: Re: Fairing reuse
Post by: meekGee on 03/16/2017 05:08 PM
Lifting the fairing does not seem to me nearly as challenging as catching one on the fly.

True, but ironically, the same helicopter that can catch a fairing may not be able to take off with one...

Fuel weight is a big deal for helicopters in long range operations. 

Also, the weight you can carry while move forward is higher than what you can carry while hovering, so a helicopter may grab a fairing, and actually not be able to set it down, until later, when it burned off the rest of its fuel.

Ah, but at sea level you get more lift than at whatever altitude they'll be catching them at.  But then Florida air may be warmer.  Helicopters are a pain in the a**.
Title: Re: Fairing reuse
Post by: envy887 on 03/16/2017 06:01 PM
Why would they use precision GPS-guided chutes if they were going after them with a helo? The whole point of guidance is to drop them somewhere specific.
Title: Re: Fairing reuse
Post by: Kaputnik on 03/16/2017 06:29 PM
If helicopters are out of the question, the only feasible alternative that I can think of is parachuting down onto a huge inflatable raft. But it really would need to be impressively large- precision airdrops are only 50m accurate and I'm sure that's with a relatively dense and sturdy crate as cargo, not a big floppy fairing half that catches the wind and probably needs a low impact speed.

You have to wonder how they would then retrieve the fairing from within the raft, which would need to be very soft to act as any kind of a cushion.

It will be fascinating to see how they are going to do this.
Title: Re: Fairing reuse
Post by: Lar on 03/16/2017 06:52 PM
The fact that CCAFS is an air force base should fare well for helicopters catching fairings

Specifically, CCAFS and the 920th Rescue Wing (HC-130P, HH-60G) are both headquartered at nearby Patrick AFB.
Yeah, but it's not like SpaceX is going to use military assets to recover fairings.
Yeah, but that part of FL is pretty nice to live in, and ex Air Force helo drivers[1] that are hot shots might be fairly easy to find around there since they might want to retire there after 20 in the AF and out... So kind of using military SURPLUS assets, as it were. :)

1 - not that I know anyone like that.
Title: Re: Fairing reuse
Post by: Zed_Noir on 03/17/2017 09:50 PM
Lifting the fairing does not seem to me nearly as challenging as catching one on the fly.

True, but ironically, the same helicopter that can catch a fairing may not be able to take off with one...

Fuel weight is a big deal for helicopters in long range operations. 

Also, the weight you can carry while move forward is higher than what you can carry while hovering, so a helicopter may grab a fairing, and actually not be able to set it down, until later, when it burned off the rest of its fuel.

Ah, but at sea level you get more lift than at whatever altitude they'll be catching them at.  But then Florida air may be warmer.  Helicopters are a pain in the a**.

Just fitted an inflight refueling kit on the helicopter. So it isn't carrying a lot of fuel during the recovery, then top up after recovery.
Title: Re: Fairing reuse
Post by: Robotbeat on 03/18/2017 01:24 AM
Oh great, inflight refueling...

This is looking more and more like a bad idea.
Title: Re: Fairing reuse
Post by: dorkmo on 03/18/2017 05:00 AM
ignoring all the cons, would in-air recovery be the least stressful option on the fairing structure? or does it not even have that going for it?
Title: Re: Fairing reuse
Post by: Kaputnik on 03/18/2017 06:23 AM
ignoring all the cons, would in-air recovery be the least stressful option on the fairing structure? or does it not even have that going for it?

It can be pretty gentle. The aircraft matches velocity with the target and then decelerates it gradually.
Title: Re: Fairing reuse
Post by: Hobbes-22 on 03/18/2017 09:56 AM
ignoring all the cons, would in-air recovery be the least stressful option on the fairing structure? or does it not even have that going for it?

US armed forces and CIA use the Fulton (https://en.wikipedia.org/wiki/Fulton_surface-to-air_recovery_system) surface-to-air recovery system to pick up people from the ground without landing. An agent behind enemy lines launches a balloon with a line attached to it. A C-130 flies over, snatches the line and then reels in the agent. By using a long line, the acceleration load on the agent was limited, "the person being picked up experienced less of a shock than during a parachute opening."

So even with a fixed-wing aircraft, this recovery method can be made survivable for humans and other fragile loads.
Title: Re: Fairing reuse
Post by: Zed_Noir on 03/18/2017 02:00 PM
Oh great, inflight refueling...

This is looking more and more like a bad idea.

Most of the combat SAR helos of the USAF are already equipped with the inflight refueling kit. They need it for extended operational radius and/or time on station. 
Title: Re: Fairing reuse
Post by: JamesH65 on 03/18/2017 02:50 PM
Oh great, inflight refueling...

This is looking more and more like a bad idea.

Most of the combat SAR helos of the USAF are already equipped with the inflight refueling kit. They need it for extended operational radius and/or time on station.

They have unlimited cash, and own the refueling tankers...and they ain't cheap.
Title: Re: Fairing reuse
Post by: meekGee on 03/18/2017 03:50 PM
Oh great, inflight refueling...

This is looking more and more like a bad idea.

Most of the combat SAR helos of the USAF are already equipped with the inflight refueling kit. They need it for extended operational radius and/or time on station.

They have unlimited cash, and own the refueling tankers...and they ain't cheap.
Heli-on-barge is an option to consider, since it eliminates half the range, and maybe the whole "fly out before launch" thing.

If the fairing ends up close enough to the barge, the helicopter might take off only after launch.

(On RTLS launches, there isn't even a conflict)
Title: Re: Fairing reuse
Post by: chalz on 03/18/2017 10:31 PM
Not to state the obvious too much but since fairings come in halves all these special operations have to be done twice and simultaneously. This makes catching it look daunting. Two barges, two landing pads, two refuelling ops, two specialist pilots. How close could the Heli's get to each other? And what happens if you only catch one, how useful would it be without its partner?
Title: Re: Fairing reuse
Post by: meekGee on 03/19/2017 12:53 AM
Not to state the obvious too much but since fairings come in halves all these special operations have to be done twice and simultaneously. This makes catching it look daunting. Two barges, two landing pads, two refuelling ops, two specialist pilots. How close could the Heli's get to each other? And what happens if you only catch one, how useful would it be without its partner?
Yup, from day one, the helicopter side seems very very difficult.

Unless they are unmanned, it pushes every edge of the envelope, and as you point out, including safety.

But clearly SpaceX has some plan in mind.  Hope we find out soon.
Title: Re: Fairing reuse
Post by: Zed_Noir on 03/19/2017 01:48 PM
After some thinking. Maybe SX will just added a parachute with radar transponder and some floatation devices to the PLF. Then fished the 2 PLF halves out of the water with a crane. Might need a couple of spotter aircraft to tracked the PLF descends and maintained visual contact until recovery assets are on the scene.
Title: Re: Fairing reuse
Post by: guckyfan on 03/19/2017 07:01 PM
After some thinking. Maybe SX will just added a parachute with radar transponder and some floatation devices to the PLF. Then fished the 2 PLF halves out of the water with a crane. Might need a couple of spotter aircraft to tracked the PLF descends and maintained visual contact until recovery assets are on the scene.

Sounds reasonable but Gwynne Shotwell said in her LC-39A interview that they don't want the fairing to get wet. Which surprised me somewhat.
Title: Re: Fairing reuse
Post by: Bargemanos on 03/19/2017 09:08 PM
After some thinking. Maybe SX will just added a parachute with radar transponder and some floatation devices to the PLF. Then fished the 2 PLF halves out of the water with a crane. Might need a couple of spotter aircraft to tracked the PLF descends and maintained visual contact until recovery assets are on the scene.
Sounds reasonable but Gwynne Shotwell said in her LC-39A interview that they don't want the fairing to get wet. Which surprised me somewhat.
Encapsulate just before splash down? Somewhat like the mars rovers.

Or is it possible to use the gliding shape of the half fairing to slow down speed enough to splash down real gently. Maby with the use of droge chutes for stability and if needed main chutes to slow down even further
Title: Re: Fairing reuse
Post by: matthewkantar on 03/19/2017 09:36 PM
SpaceX has stated the fairing are not going in the water.

Matthew
Title: Re: Fairing reuse
Post by: Space Ghost 1962 on 03/19/2017 09:42 PM
They aren't intended for immersion. You'll have to get them w/o reaching the water.

Which means either airborne recovery e.g. snag them with a drone, not unlike with Smart recovery, or you fly them back to land, and somehow recover them.
Title: Re: Fairing reuse
Post by: envy887 on 03/19/2017 11:58 PM
They aren't intended for immersion. You'll have to get them w/o reaching the water.

Which means either airborne recovery e.g. snag them with a drone, not unlike with Smart recovery, or you fly them back to land, and somehow recover them.

Or land them on something floating on the water.
Title: Re: Fairing reuse
Post by: meekGee on 03/20/2017 12:43 AM
They aren't intended for immersion. You'll have to get them w/o reaching the water.

Which means either airborne recovery e.g. snag them with a drone, not unlike with Smart recovery, or you fly them back to land, and somehow recover them.

Or land them on something floating on the water.

To the extent that they can remain "dry", in wave action, salt spray, etc.

And that bouncing around on the waves doesn't exceed structural limits, or that at least such issues can be identified afterwards.
Title: Re: Fairing reuse
Post by: Lars-J on 03/20/2017 03:39 AM
They aren't intended for immersion. You'll have to get them w/o reaching the water.

Which means either airborne recovery e.g. snag them with a drone, not unlike with Smart recovery, or you fly them back to land, and somehow recover them.

Or the third option (most likely IMO), precision land them on a barge or boat.
Title: Re: Fairing reuse
Post by: ChrisWilson68 on 03/20/2017 07:21 AM
They aren't intended for immersion. You'll have to get them w/o reaching the water.

Which means either airborne recovery e.g. snag them with a drone, not unlike with Smart recovery, or you fly them back to land, and somehow recover them.

Or the third option (most likely IMO), precision land them on a barge or boat.

Then, just refuel them and let them fly themselves back to the launch site.
Title: Re: Fairing reuse
Post by: Kaputnik on 03/20/2017 09:17 PM
In the absence of better information we are going round and round in circles here. I think that every possibility has been suggested by somebody at some point. By way of recap, I think these are:
- mid air recovery by long range helo
- mid air recovery by short range ship based helo
- unmanned variant of the above
- mid air recovery by fixed wing aircraft with handover to helo for landing
- precision touchdown on ship/barge
- precision touchdown on inflatable raft
- modified PLF with aerodynamic control surfaces for flyback

The fascinating thing is that *all* of these options can be discounted as unworkable for various reasons.
Have I missed any off the list?
Title: Re: Fairing reuse
Post by: Lars-J on 03/20/2017 10:00 PM
In the absence of better information we are going round and round in circles here. I think that every possibility has been suggested by somebody at some point. By way of recap, I think these are:
- mid air recovery by long range helo
- mid air recovery by short range ship based helo
- unmanned variant of the above
- mid air recovery by fixed wing aircraft with handover to helo for landing
- precision touchdown on ship/barge
- precision touchdown on inflatable raft
- modified PLF with aerodynamic control surfaces for flyback

The fascinating thing is that *all* of these options can be discounted as unworkable for various reasons.
Have I missed any off the list?

How in the world is precision touchdown on ship/barge/raft unworkable?
Title: Re: Fairing reuse
Post by: docmordrid on 03/21/2017 12:44 AM
In the absence of better information we are going round and round in circles here. I think that every possibility has been suggested by somebody at some point. By way of recap, I think these are:
- mid air recovery by long range helo
- mid air recovery by short range ship based helo
- unmanned variant of the above
- mid air recovery by fixed wing aircraft with handover to helo for landing
- precision touchdown on ship/barge
- precision touchdown on inflatable raft
- modified PLF with aerodynamic control surfaces for flyback

The fascinating thing is that *all* of these options can be discounted as unworkable for various reasons.
Have I missed any off the list?

How in the world is precision touchdown on ship/barge/raft unworkable?

Airborne Systems Dragonfly precision drop system, good for 10,000 lbs, only specs a 250m accuracy.

http://airborne-sys.com/wp-content/uploads/2016/08/ASG-DragonFly-20170206-English.pdf
Title: Re: Fairing reuse
Post by: ChrisC on 03/21/2017 02:19 AM
In the absence of better information we are going round and round in circles here. I think that every possibility has been suggested by somebody at some point.

And we will again in about two weeks.  Wash, rinse, repeat until more facts come in.  See you in April.
Title: Re: Fairing reuse
Post by: meekGee on 03/21/2017 05:23 AM
In the absence of better information we are going round and round in circles here. I think that every possibility has been suggested by somebody at some point. By way of recap, I think these are:
- mid air recovery by long range helo
- mid air recovery by short range ship based helo
- unmanned variant of the above
- mid air recovery by fixed wing aircraft with handover to helo for landing
- precision touchdown on ship/barge
- precision touchdown on inflatable raft
- modified PLF with aerodynamic control surfaces for flyback

The fascinating thing is that *all* of these options can be discounted as unworkable for various reasons.
Have I missed any off the list?
You can add long line dropoff from fixed wing aircraft. I don't think it was ever tried with something this big tho
Title: Re: Fairing reuse
Post by: JamesH65 on 03/21/2017 09:24 AM
Anyone have any guesses on what the glide angle of a fairing is? Perhaps with fins/winglets? And how far downrange are they released, and how fast are they going at release?
Title: Re: Fairing reuse
Post by: Kaputnik on 03/21/2017 11:22 AM
In the absence of better information we are going round and round in circles here. I think that every possibility has been suggested by somebody at some point. By way of recap, I think these are:
- mid air recovery by long range helo
- mid air recovery by short range ship based helo
- unmanned variant of the above
- mid air recovery by fixed wing aircraft with handover to helo for landing
- precision touchdown on ship/barge
- precision touchdown on inflatable raft
- modified PLF with aerodynamic control surfaces for flyback

The fascinating thing is that *all* of these options can be discounted as unworkable for various reasons.
Have I missed any off the list?
You can add long line dropoff from fixed wing aircraft. I don't think it was ever tried with something this big tho

How does that work? Do you reel it out realky fast, to negate airspeed, or do you fly a circle with a long tow?
Title: Re: Fairing reuse
Post by: Kaputnik on 03/21/2017 11:28 AM
Anyone have any guesses on what the glide angle of a fairing is? Perhaps with fins/winglets? And how far downrange are they released, and how fast are they going at release?

I can't put any number to this right now (making it opinion rather than analysis) but I think the terminal velocity of a fairing half will be pretty low, making for a slow glide and a short range. Also, they are released ahortly after staging and will continue up on a ballistic trajectory alongside the first stage, making entry at a similar distance downrange (they are too high in the atmosphere, I think, to be able to make any aerodynamic manoeuvres).
So, if y are wondering whether the fairing halves would be able to glide back towards to the landing site for easier helo recovery, the answer is probably no.
Title: Re: Fairing reuse
Post by: meekGee on 03/21/2017 01:51 PM
In the absence of better information we are going round and round in circles here. I think that every possibility has been suggested by somebody at some point. By way of recap, I think these are:
- mid air recovery by long range helo
- mid air recovery by short range ship based helo
- unmanned variant of the above
- mid air recovery by fixed wing aircraft with handover to helo for landing
- precision touchdown on ship/barge
- precision touchdown on inflatable raft
- modified PLF with aerodynamic control surfaces for flyback

The fascinating thing is that *all* of these options can be discounted as unworkable for various reasons.
Have I missed any off the list?
You can add long line dropoff from fixed wing aircraft. I don't think it was ever tried with something this big tho

How does that work? Do you reel it out realky fast, to negate airspeed, or do you fly a circle with a long tow?
The latter.

Long line, draggy device, fly in a circle.

Legend has it that you can hand pick mail that way, but legends are famously exaggerated....

And it's a hypothetical, I don't think that's really in the plan.
Title: Re: Fairing reuse
Post by: LouScheffer on 03/21/2017 02:48 PM
In the absence of better information we are going round and round in circles here. I think that every possibility has been suggested by somebody at some point. By way of recap, I think these are:
- mid air recovery by long range helo
- mid air recovery by short range ship based helo
- unmanned variant of the above
- mid air recovery by fixed wing aircraft with handover to helo for landing
- precision touchdown on ship/barge
- precision touchdown on inflatable raft
- modified PLF with aerodynamic control surfaces for flyback

The fascinating thing is that *all* of these options can be discounted as unworkable for various reasons.
Have I missed any off the list?
How in the world is precision touchdown on ship/barge/raft unworkable?
Airborne Systems Dragonfly precision drop system, good for 10,000 lbs, only specs a 250m accuracy.
http://airborne-sys.com/wp-content/uploads/2016/08/ASG-DragonFly-20170206-English.pdf
But parachutes can be much more accurate.  Parachute landing competitions (http://www.fai.org/ipc-our-sport/accuracy-landing-freefall-style) have accuracies in the low cm range (they don't even record above 16cm, which is considered a complete miss).  So I would not rule this one out, if SpaceX cares to put some work into landing accuracy.
Title: Re: Fairing reuse
Post by: Swoopert on 03/21/2017 04:19 PM
But parachutes can be much more accurate.  Parachute landing competitions (http://www.fai.org/ipc-our-sport/accuracy-landing-freefall-style) have accuracies in the low cm range (they don't even record above 16cm, which is considered a complete miss).  So I would not rule this one out, if SpaceX cares to put some work into landing accuracy.

The types of parachute used for accuracy landing competitions are distinctly unsuited to these purposes. They are designed to open at very low speed, come in at an extremely steep glide angle, and require a very small range of wind conditions (usually less than 10-15kts and steady) to achieve that level of accuracy, which you're unlikely to see in the middle of the ocean where the fairings will end up due to the poor glide angle.

Swoopert.

2-time British Collegiate Parachute Accuracy champion
Title: Re: Fairing reuse
Post by: Kaputnik on 03/21/2017 04:55 PM
Another one to suggest and instantly dismiss:
Steerable foil landing on a moving platform (the idea being that the moving platform, e.g. a ship with a cushion on its aft deck, or towing an inflatable raft) can compensate somewhat for the inaccuracy of the incoming fairing.
Having seen an episode of Top Gear where they tried landing a parachutist in the back of a moving car, it seems that moving the landing target only makes things much harder...
Title: Re: Fairing reuse
Post by: LouScheffer on 03/21/2017 04:59 PM
But parachutes can be much more accurate.  Parachute landing competitions (http://www.fai.org/ipc-our-sport/accuracy-landing-freefall-style) have accuracies in the low cm range (they don't even record above 16cm, which is considered a complete miss).  So I would not rule this one out, if SpaceX cares to put some work into landing accuracy.

The types of parachute used for accuracy landing competitions are distinctly unsuited to these purposes. They are designed to open at very low speed, come in at an extremely steep glide angle, and require a very small range of wind conditions (usually less than 10-15kts and steady) to achieve that level of accuracy, which you're unlikely to see in the middle of the ocean where the fairings will end up due to the poor glide angle.

Swoopert.

2-time British Collegiate Parachute Accuracy champion
I certainly agree you could not use the type of parachute used in accuracy contests, but you don't need cm class accuracy either.  If you could do only two orders of magnitude worse than humans with special parachutes, you'd have meter class accuracy, which would be plenty good enough to hit a ship/barge/raft.

In 1958, using parachutes certainly not optimized for accuracy,  parachutists were achieving 4 meter accuracy (http://www.parachutehistory.com/men/sanbornl.html).  Surely with modern parachute technology, we can do at least as well...
Title: Re: Fairing reuse
Post by: dwheeler on 03/21/2017 06:06 PM
Another one to suggest and instantly dismiss:
Steerable foil landing on a moving platform (the idea being that the moving platform, e.g. a ship with a cushion on its aft deck, or towing an inflatable raft) can compensate somewhat for the inaccuracy of the incoming fairing.
Having seen an episode of Top Gear where they tried landing a parachutist in the back of a moving car, it seems that moving the landing target only makes things much harder...

Yeah, if the blokes at Top Gear found it difficult I'm sure the hardware/software/aero engineers at SpaceX wouldn't stand a chance...  ::) :P
Title: Re: Fairing reuse
Post by: RoboGoofers on 03/21/2017 06:57 PM
The catch idea seems a bit crazy to me because if you could catch a fairing, why not a second stage?
Title: Re: Fairing reuse
Post by: Comga on 03/21/2017 07:09 PM
The catch idea seems a bit crazy to me because if you could catch a fairing, why not a second stage?
If you have to ask, you need to do more research
The fairings don't re-enter from orbital speed, come in not too far from the launch site, have low ballistic coefficients and terminal velocity, have much lower mass, and detract from payload at well below the 1:1 ratio of the second stage.
Title: Re: Fairing reuse
Post by: Kaputnik on 03/21/2017 07:24 PM
I don't think we can extrapolate directly from a human parachutist to a fairing descending under a foil.

The human has three distinct advantages: great control authority (big control actuators, aka arms), extremely good undercarriage with long travel (aka legs), and much higher density (this varies from human to human, of course).

So a human can come in at a relatively higher speed, without being blown around by the wind, and make a fairly forceful impact whilst remaining intact.

Gut feeling is that a fairing half is not the sturdiest of things, when it comes to sudden impact loads. But anybody with insight into this please chip in.
Title: Re: Fairing reuse
Post by: RoboGoofers on 03/21/2017 07:53 PM
The catch idea seems a bit crazy to me because if you could catch a fairing, why not a second stage?
If you have to ask, you need to do more research
The fairings don't re-enter from orbital speed, come in not too far from the launch site, have low ballistic coefficients and terminal velocity, have much lower mass, and detract from payload at well below the 1:1 ratio of the second stage.

yeah I'm just hand-waving away all of that. I'm only talking about the difficulty of the catch and the effects on the aircraft. After all, catching something as large as a fairing hasn't been done before, either.

Then again ULA plans to air-catch their Vulcan engines. ::)

(Edited for clarity)

another edit:
At the end of this video they say "it's conceivable that this technique can be scaled up to payloads up to 22,000 lbs" so maybe catching the fairing isn't that crazy, though the logistics are still hard.
https://www.youtube.com/watch?v=3cnr3pX4tyw
Title: Re: Fairing reuse
Post by: Comga on 03/21/2017 08:03 PM
The catch idea seems a bit crazy to me because if you could catch a fairing, why not a second stage?
If you have to ask, you need to do more research
The fairings don't re-enter from orbital speed, come in not too far from the launch site, have low ballistic coefficients and terminal velocity, have much lower mass, and detract from payload at well below the 1:1 ratio of the second stage.

yeah just hand-waving away all of that. After all, catching something as large as a fairing hasn't been done before, either.
Then again ULA plans to air-catch their Vulcan engines. ::)

It is not clear who you are accusing of "hand waving".
Vulcan engine recovery will also be from speeds well below orbital, plan on using a massive heat shield, and are again part of the first stage, not the second.  (Fairings come off around staging, so their trajectories and mass impacts are very much like first stage elements.)  And it's still a decade out on ULA's plan.
Title: Re: Fairing reuse
Post by: manoweb on 03/21/2017 08:32 PM
Do you think ULA was serious when they said they will catch the engines? Was it not only because at the time, SpaceX announced something crazy about landing a stage, and they felt compelled to say something as crazy? Sorry I do not follow the ULA forum so maybe I do not have new info on the subject.
Title: Re: Fairing reuse
Post by: Comga on 03/21/2017 09:57 PM
Do you think ULA was serious when they said they will catch the engines? Was it not only because at the time, SpaceX announced something crazy about landing a stage, and they felt compelled to say something as crazy? Sorry I do not follow the ULA forum so maybe I do not have new info on the subject.

Many years ago, before SpaceX landed any rockets, "our own" Jonathan Goff posted about recovering the RD-180 engines of an Atlas-V using helicopter caught parafoils.  ULA has studied this.  It's not impossible.  If they need to address the issue that they are developing a new expendable rocket while a competitor is perfecting reusability, they throw up that slide.  How serious they are is hard to know.
Title: Re: Fairing reuse
Post by: TrevorMonty on 03/21/2017 10:11 PM
The catch idea seems a bit crazy to me because if you could catch a fairing, why not a second stage?
If you have to ask, you need to do more research
The fairings don't re-enter from orbital speed, come in not too far from the launch site, have low ballistic coefficients and terminal velocity, have much lower mass, and detract from payload at well below the 1:1 ratio of the second stage.

yeah just hand-waving away all of that. After all, catching something as large as a fairing hasn't been done before, either.
Then again ULA plans to air-catch their Vulcan engines. ::)

It is not clear who you are accusing of "hand waving".
Vulcan engine recovery will also be from speeds well below orbital, plan on using a massive heat shield, and are again part of the first stage, not the second.  (Fairings come off around staging, so their trajectories and mass impacts are very much like first stage elements.)  And it's still a decade out on ULA's plan.
The SMART system could be applied to 2nd stage or its engines, as HIAD is design for orbital reentry speeds.
At one stage NASA considered testing HIAD using Cygnus.
Title: Re: Fairing reuse
Post by: meekGee on 03/22/2017 01:13 AM
We're *drifting* off topic.

Sorry, had to say it.

But yeah, the difficult part in second stage recovery is not snagging it, since it actually can occur closer to home base than the fairings can.  The problem is whether the weight penalty of the heat shield and maybe structural reinforcement is worth it.

Title: Re: Fairing reuse
Post by: darkenfast on 03/22/2017 02:52 AM
Okay, I KNOW they said they don't want to get it wet, but I can't help but notice that the fairing halves are most of the way to being a boat.  Seal up any openings and perhaps an inflatable "bulkhead" at the back (bottom, when on the rocket) and a parachute.  The insides of the fairing are probably what they don't want to get a lot of salt-water on.  If the paint (or SPAM, or whatever coats the outside) is tolerant, the halves will just float until pick-up.  I wouldn't tow them, I would crane them into a cradle.

But...they said they wouldn't want to get them wet.  I imagine they have something else planned.  Oh, well.
Title: Re: Fairing reuse
Post by: manoweb on 03/22/2017 04:58 AM
darkenfast, yes I was also surprised by that declaration. What I mean is: composites should have a pretty good resistance to saltwater, the fairing is not made out of mild steel; we are also talking about few hours max, not years floating in the sea. If recoveries become the norm they can always invest in better paint, sealing etc.
Title: Re: Fairing reuse
Post by: meekGee on 03/22/2017 07:03 AM
darkenfast, yes I was also surprised by that declaration. What I mean is: composites should have a pretty good resistance to saltwater, the fairing is not made out of mild steel; we are also talking about few hours max, not years floating in the sea. If recoveries become the norm they can always invest in better paint, sealing etc.
Maybe the problem is bouncing around unpredictably on the waves?
Title: Re: Fairing reuse
Post by: darkenfast on 03/22/2017 08:09 AM
darkenfast, yes I was also surprised by that declaration. What I mean is: composites should have a pretty good resistance to saltwater, the fairing is not made out of mild steel; we are also talking about few hours max, not years floating in the sea. If recoveries become the norm they can always invest in better paint, sealing etc.
Maybe the problem is bouncing around unpredictably on the waves?
Obviously, in rough weather, some water is going to get in.  As hulls go, this is a very buoyant potential boat.  In the kind of waves and swells that you get out in deep water, I believe it would just ride over everything, responding very quickly.  It would probably roll a lot because of its circular cross section.  Something called a "flopper-stopper" might help (it hangs over the side, like a sea anchor, but straight down - the drag slows the roll).  The chute(s) would make something of a sea-anchor, unfortunately if it didn't collapse, it would be like chasing a light dinghy flying a spinnaker!  Jettison capability might be good. 

Having said all that, it will be interesting to see what they REALLY have planned.
Title: Re: Fairing reuse
Post by: AncientU on 03/22/2017 10:27 PM
darkenfast, yes I was also surprised by that declaration. What I mean is: composites should have a pretty good resistance to saltwater, the fairing is not made out of mild steel; we are also talking about few hours max, not years floating in the sea. If recoveries become the norm they can always invest in better paint, sealing etc.

The fairing uses honeycomb aluminum and carbon composites as I recall.
Question: Are the void areas in the honeycomb filled and/or vented*? 

Doesn't seem like a good idea to have them air-filled and working to de-laminate the structure when under vacuum (zero pressure) externally.  But if vented, they could fill with sea water if landed in the pond which would destroy the fairing or at least make it unfit for reuse.

*All of the vacuum components we build are provided a means to vent each of the void areas to ensure no gas is trapped after vacuum is drawn.
Title: Re: Fairing reuse
Post by: iamlucky13 on 03/23/2017 09:24 PM
Oh great, inflight refueling...

This is looking more and more like a bad idea.

Most of the combat SAR helos of the USAF are already equipped with the inflight refueling kit. They need it for extended operational radius and/or time on station.

They have unlimited cash, and own the refueling tankers...and they ain't cheap.

And they're able to keep up with a C-130 because they're not towing a giant air brake.


How in the world is precision touchdown on ship/barge/raft unworkable?

Airborne Systems Dragonfly precision drop system, good for 10,000 lbs, only specs a 250m accuracy.

http://airborne-sys.com/wp-content/uploads/2016/08/ASG-DragonFly-20170206-English.pdf

Is that because 250m is the best theoretically achievable with current technology, or because there has been minimal incentive so far to improve the system to better than 250m accuracy?

It has not been demonstrated as workable, but that is different from being known to be unworkable.

darkenfast, yes I was also surprised by that declaration. What I mean is: composites should have a pretty good resistance to saltwater, the fairing is not made out of mild steel; we are also talking about few hours max, not years floating in the sea. If recoveries become the norm they can always invest in better paint, sealing etc.

The composites are probably not their concern. The fairing is more than just a shell. There are mechanical systems inside it like pushers and latch actuators that are potentially susceptible to both corrosion and salt fouling.
Title: Re: Fairing reuse
Post by: Robotbeat on 03/23/2017 10:29 PM
You can get GPS-guided parafoil payload systems that, with tweaking, can reliably hit the barge deck of an ASDS (50m x 90m). So maybe put a huge net on 4 poles (one on each corner of an ASDS) 15m high.
Title: Re: Fairing reuse
Post by: virnin on 03/23/2017 10:36 PM
You can get GPS-guided parafoil payload systems that, with tweaking, can reliably hit the barge deck of an ASDS (50m x 90m). So maybe put a huge net on 4 poles (one on each corner of an ASDS) 15m high.

That leads to the, unanswerable by us, question of how many fairings would they have to recover to pay for at least two, but more likely four, additional ASDS?
Title: Re: Fairing reuse
Post by: Robotbeat on 03/23/2017 10:38 PM
Could be a smaller and simpler vessel than an ASDS, but here's a shot:
Title: Re: Fairing reuse
Post by: nacnud on 03/23/2017 10:39 PM
I still like the scaneagle method of capture. Rather that thinking of landing these think of flying them through a volume of space within which they can be captured.
Title: Re: Fairing reuse
Post by: LouScheffer on 03/23/2017 10:58 PM

Is that because 250m is the best theoretically achievable with current technology, or because there has been minimal incentive so far to improve the system to better than 250m accuracy?

250m is definitely not a theoretical limit.    Human in the loop systems  (https://arc.aiaa.org/doi/abs/10.2514/6.2015-0075) have hit 17m (50% of the time), 42m 90% of the time.   Automated systems (http://www.staratechnologies.com/mosquito.html) have hit 30 m (50%).
Title: Re: Fairing reuse
Post by: Jet Black on 03/24/2017 08:13 AM
You can get GPS-guided parafoil payload systems that, with tweaking, can reliably hit the barge deck of an ASDS (50m x 90m). So maybe put a huge net on 4 poles (one on each corner of an ASDS) 15m high.

That leads to the, unanswerable by us, question of how many fairings would they have to recover to pay for at least two, but more likely four, additional ASDS?

It's not the cost of the farings themselves, but whether they provide a bottleneck in launches. Even if they only cost $100 each, if they can't make them fast enough to keep up with their launch cadence, it would still be worth investing $100,000 per launch to catch them, because it would mean that they would be able to launch more rockets, earning millions of dollars each time.
Title: Re: Fairing reuse
Post by: guckyfan on 03/24/2017 08:38 AM
You can get GPS-guided parafoil payload systems that, with tweaking, can reliably hit the barge deck of an ASDS (50m x 90m). So maybe put a huge net on 4 poles (one on each corner of an ASDS) 15m high.

That leads to the, unanswerable by us, question of how many fairings would they have to recover to pay for at least two, but more likely four, additional ASDS?

They would be a lot simpler than the Falcon ASDS. Also unlike a Falcon core it is perfectly feasible to transfer fairing halves to a ship for transport and leave the ASDS at position for a while. So just 2.
Title: Re: Fairing reuse
Post by: Basto on 03/24/2017 01:38 PM
Could be a smaller and simpler vessel than an ASDS, but here's a shot:

Another thought... aren't there two support ships that tow the barge out?  What I you had a net suspended between these two ships...
Title: Re: Fairing reuse
Post by: rsdavis9 on 03/24/2017 01:41 PM
Barges with inflatable bouncy houses.  :)
Basically like the inflatable domes that are currently available for sports events.
Inflate before landing. Allow quick deflation when fairing lands.

EDIT:
So how cheap can the barges be?
Do they need the four hydraulic props?
Could they just be actively towed? In other words 1 mph headway. Should be little or no risk to towing ship.

Title: Re: Fairing reuse
Post by: bstrong on 03/24/2017 01:56 PM
Could be a smaller and simpler vessel than an ASDS, but here's a shot:

I like this a lot. Angle the support poles outwards, and you can make do with a much smaller barge (or have a much larger net). Add the ability to quickly roll out a second net a couple of meters above the first and you can make do with one barge instead of two.
Title: Re: Fairing reuse
Post by: cscott on 03/24/2017 02:37 PM
Elon tweeted something interesting, maybe a hint at a fairing recovery experiment?
https://twitter.com/elonmusk/status/845290713776451584
Title: Re: Fairing reuse
Post by: Toast on 03/24/2017 03:15 PM
Elon tweeted something interesting, maybe a hint at a fairing recovery experiment?
https://twitter.com/elonmusk/status/845290713776451584

I don't think that has anything to do with fairing recovery, he's referring to it being the first reuse of a Falcon 9 first stage.
Title: Re: Fairing reuse
Post by: intrepidpursuit on 03/24/2017 07:10 PM
Elon tweeted something interesting, maybe a hint at a fairing recovery experiment?
https://twitter.com/elonmusk/status/845290713776451584

I don't think that has anything to do with fairing recovery, he's referring to it being the first reuse of a Falcon 9 first stage.

Referring to fate seems to indicate something experimental. He wouldn't refer to a successful launch as requiring fate, and landings have become pretty routine as well. He could just be trying to avoid over confidence, but to me that indicates something more. I think only nerds would care about the roomba, but seeing parafoils pop out of a fairing would be pretty exciting.
Title: Re: Fairing reuse
Post by: virnin on 03/24/2017 07:31 PM
You can get GPS-guided parafoil payload systems that, with tweaking, can reliably hit the barge deck of an ASDS (50m x 90m). So maybe put a huge net on 4 poles (one on each corner of an ASDS) 15m high.

That leads to the, unanswerable by us, question of how many fairings would they have to recover to pay for at least two, but more likely four, additional ASDS?

They would be a lot simpler than the Falcon ASDS. Also unlike a Falcon core it is perfectly feasible to transfer fairing halves to a ship for transport and leave the ASDS at position for a while. So just 2.

Two on each coast, so four.  Maybe 6 after Boca Chica comes online.

Agreed simpler than ASDS.  Just has to be big enough to hold the net stable during off-center catches.
Could even be manned, with crew under protective cover during catch ops.  Like a retired container ship.
Title: Re: Fairing reuse
Post by: Toast on 03/24/2017 07:39 PM
Referring to fate seems to indicate something experimental.

Relaunch of a first stage is experimental.


Title: Re: Fairing reuse
Post by: iamlucky13 on 03/24/2017 07:45 PM

Referring to fate seems to indicate something experimental. He wouldn't refer to a successful launch as requiring fate, and landings have become pretty routine as well. He could just be trying to avoid over confidence, but to me that indicates something more. I think only nerds would care about the roomba, but seeing parafoils pop out of a fairing would be pretty exciting.

Reflying a booster is experimental, and it's a significant part of SpaceX's business plan. I see nothing inconsistent with talking about fate for such a significant milestone.

Fate has bitten him twice in as many years on brand new hardware on missions thought to be routine. Although he has talked up his confidence in the past about reflight, even going as far as talking about "flight proven" hardware and booking a paying customer for the launch, I don't for one second believe he is completely free from doubts.
Title: Re: Fairing reuse
Post by: Robotbeat on 03/25/2017 12:14 AM
Referring to fate seems to indicate something experimental.

Relaunch of a first stage is experimental.
It's almost like you and iamlucky13 have no idea of who Musk is. When Musk is given an opportunity to double down, he does. No way he's just a referring to reflying a stage.
Title: Re: Fairing reuse
Post by: meekGee on 03/25/2017 12:18 AM
My vote is for the fact it's a re-launch.

Confident as he may be, you gotta get butterflies before this launch.  Are you kidding?

Title: Re: Fairing reuse
Post by: Toast on 03/25/2017 12:26 AM
Referring to fate seems to indicate something experimental.

Relaunch of a first stage is experimental.
It's almost like you and iamlucky13 have no idea of who Musk is. When Musk is given an opportunity to double down, he does. No way he's just a referring to reflying a stage.

I won't go so far as to rule out SpaceX trying something else new on this flight (after all, they're almost always trying something new, even if we don't see it), I just think Elon referring to first stage reuse is a much more likely interpretation of this tweet. Every time Elon tweets, people bend over backwards trying to interpret his tweets (and almost always trying to make them fit their personal desires), and I think people lose sight of the fact that he probably only spends less than a minute on each tweet and most likely isn't really deliberating on his word choice. In fact, I know he spent less than a minute on this tweet, because he sent out another tweet about the Model 3 less than a minute before sending out this one (plus ~50 more in the same hour).
Title: Re: Fairing reuse
Post by: Robotbeat on 03/25/2017 01:30 AM
Referring to fate seems to indicate something experimental.

Relaunch of a first stage is experimental.
It's almost like you and iamlucky13 have no idea of who Musk is. When Musk is given an opportunity to double down, he does. No way he's just a referring to reflying a stage.

I won't go so far as to rule out SpaceX trying something else new on this flight (after all, they're almost always trying something new, even if we don't see it), I just think Elon referring to first stage reuse is a much more likely interpretation of this tweet. Every time Elon tweets, people bend over backwards trying to interpret his tweets (and almost always trying to make them fit their personal desires), and I think people lose sight of the fact that he probably only spends less than a minute on each tweet and most likely isn't really deliberating on his word choice. In fact, I know he spent less than a minute on this tweet, because he sent out another tweet about the Model 3 less than a minute before sending out this one (plus ~50 more in the same hour).

You've got a good point in people over-interpreting Musk tweets. But, since we're doing it anyway: Musk often writes up drafts of tweets before he sends them. And just because it doesn't take long to say something doesn't mean he wasn't thinking about such things for a long time.

Look, everyone already knows about the fact that SES10 is a recovered booster. There's zero surprise, there, and while the reusability-can't-work goal-post-movers might have at one point said "but they just /recovered/ a rocket, they haven't actually launched it again," I really don't think this is terribly amazing (it is expected), at least not worth Musk noting what is already obvious (that SES10 will be a reused core) as if it's something unexpected.

For context, this is the actual exchange:
Quote
BlueBowles:
@elonmusk how excited are you about the SES launch next week?! I don't know how you're focused on model 3 with that ahead! #makinghistory
Quote
Elon Musk‏:
@BlueBowles If fate is on our side, it will be amazing. Will talk about that in detail next week.

What is there to discuss in detail?
Title: Re: Fairing reuse
Post by: dglow on 03/25/2017 01:39 AM
What is there to discuss in detail?

The Roomba. It'll be a 'cool new surprise' for the public and nice embodiment of their efficiency and reuse ambitions.
Title: Re: Fairing reuse
Post by: Robotbeat on 03/25/2017 01:44 AM
What is there to discuss in detail?

The Roomba. It'll be a 'cool new surprise' for the public and nice embodiment of their efficiency and reuse ambitions.
That's my point. It's something extra like Optimus Prime, fairing recovery, or something else like that. If Musk is discussing such stuff in detail, I doubt he'd ignore Optimus Prime, even if it weren't (for whatever reason) ready for this flight.

(But I think they're trying very hard to get it to work for this flight. That's why there are work lights around it. People are working late on this.
Title: Re: Fairing reuse
Post by: georgegassaway on 03/25/2017 06:00 AM
BTW - what is the estimated mass of each  fairing half?

Given the potential changes in wind velocity at sea, I'm not so sure that a big net over a station-keeping barge (thrusters in four corners) would allow for enough of a margin for error. Also very hard to justify the cost of outfitting two barges for that, even at less cost than an ASDS landing barge.

A BIG net between two ships? They can't station keep, they'd have to be moving thru the water at some minimal speed to try to be parallel, as Navy ships have to do in refueling or taking on other supplies side-by-side from a resupply ship. That is an idea that certainly has simplicity (?) going for it (Well, relative to some other ideas), but does not seem very practical. Indeed with the mass of the fairings laid into such a big net, then the net would want to sag and pull the ships towards each other. So one ship would have to steer away from parallel to keep net taut, and may need to do so in very rough seas. That seems like a lot of precise steering to expect of a sea vessel not designed for precise maneuvering. Plus how to get the fairings out of the big big net onto the deck of a ship without a swell allowing the net to go slack and let the fairings dip into the sea water even once, negating the whole reason for a dry landing.

They would be a lot simpler than the Falcon ASDS. Also unlike a Falcon core it is perfectly feasible to transfer fairing halves to a ship for transport and leave the ASDS at position for a while. So just 2.

My thoughts, ONE barge, with aviation fuel storage onboard.  Two helicopters, each to air-snag one fairing coming down on gliding parafoil as shown in a previous post. The helicopter lowers the fairing half onto the deck and lands at one end. The other copter lowers the other fairing half and lands at the other end. Copters get refueled (if necessary, especially if they flew directly from on shore shortly before launch) and then fly back to shore alone, the fairings stay on the barge which is towed back to port.

It may not end up that way, but that seems feasible given that SpaceX does not want them to land in the ocean.

I just do not think it is very practical to air-snag the fairings then fly them back to shore under the copter. The fairings would have a lot of air drag and relatively light for their area, and would need to be flown back at a relatively low speed such as perhaps 30 knots (or perhaps less). That is a long time to be flying back from 200 or more miles out without any practical way to refuel (the idea of doing air to air refueling behind a C-130 while towing one of those ..... no way in Hades.  And AFAIK there are no civilian/commercial refueling capabilities. Only the military has such assets, which would be extremely unlikely to be used for a commercial venture such as this).

However, a lot of the mission-to-mission expense of using typical helicopters could be greatly reduced, if SpaceX developed something almost revolutionary. Because they don't have to truly design anything new, mostly scale up and build to their needs. There are big electric powered multicopters that can carry people. Scale that up a bit more, to develop a multicopter capable of carrying the mass of a payload fairing, and the automation (perhaps with remote human assist) to track down, approach, and air-snag the parachute. Then the rest could be totally automated like a hobby-type multicopter doing an automatic return to home.

I'm not counting on that actually happening. Not likely, but possible.

 Probably sounds too far-fetched right now. But then so did the idea of them doing a "Roomba" 6 months ago, or a rocket powered landing of a Falcon-9 on a barge 7 years ago. Certainly it would cost more to develop and build these than it would cost to use manned helicopters for the first few missions. But if they worked, over time they'd be far more cost effective and earn their keep. And in case of disaster, no risk to human pilots and the more expensive helicopters they fly.

The plus side of it is that making a full sized prototype of such a multicopter  would not require a long time.  Electric motor characteristics , LiPo batteries, and propellers are a known quantity so that choosing the right combo for a scaling up, for the desired payload capability, would not be too hard.  The level of automation would be the bigger issue to work out and that could be tested out and perfected in smaller scale. 

I wonder where in  the Musk-Verse that they might find anyone who knows about how to make a vehicle know exactly where it is and how to self-navigate? As well as to visually recognize certain shapes (like a parafoil canopy), and exactly how close it is to such a "target shape" in 3 dimensions, and guide itself along the correct path to intercept from behind?  :)   And at that, real-time remote human assistance might also be worth including in case the automation might be too difficult to handle every aspect of it reliably enough.

Whatever they do, or may have already tested on a flight, if they do get it to work, it'll be really great to see whatever method and techniques they use for safely landing fairings without getting wet.

Of course they may have something else up their sleeves that's not been considered much in this thread......   :)

(Yeah, I went shopping for this unreal photo, and not seriously suggesting it)
Title: Re: Fairing reuse
Post by: Kaputnik on 03/25/2017 10:56 AM
Each fairing half is estimated at about a tonne (see further back in this thread).

An in house developed drone would hbe a very Musky way of tackling this. But it would be a pretty big project in its own right. Would an upsized quad opter have the speed and manoeuvrability for the task?
Title: Re: Fairing reuse
Post by: rsdavis9 on 03/25/2017 11:38 AM
barge landing on air bag.
https://www.youtube.com/watch?v=3KwyftaLT-k
Title: Re: Fairing reuse
Post by: meekGee on 03/25/2017 02:49 PM
Each fairing half is estimated at about a tonne (see further back in this thread).

An in house developed drone would hbe a very Musky way of tackling this. But it would be a pretty big project in its own right. Would an upsized quad opter have the speed and manoeuvrability for the task?
Quadcopters as a form factor are much less efficient than helicopters when it comes to flying range, and automated helicopters exist.

But yes - the idea of a drone is very Musky.
Title: Re: Fairing reuse
Post by: douglas100 on 03/25/2017 04:38 PM
If you've got a vessel downrange, then the range of the helicopters or drones is less of an issue. They would be fueled or recharged on the ship or barge. They would only take off only after the rocket had left the pad. Essentially you'd be doing SMART twice, in short order. The cost of operating a second downrange vessel is an important consideration, of course.
Title: Re: Fairing reuse
Post by: Robotbeat on 03/25/2017 05:16 PM
A Megawatt peak should be more than sufficient to carry a fairing halve with a multicopter video. A battery similar to what's in a Tesla.

Scales better electrically with more motors than simply bigger motors. So 60 motors, maybe?

Anyway, I doubt they'll pursue a custom flying fairing catcher, but it's fun to speculate.
Title: Re: Fairing reuse
Post by: georgegassaway on 03/25/2017 06:40 PM
Multicopters can fly pretty fast, and are very maneuverable (check out video of “Drone racing”.  I do not know what the record speed is, but some can fly over 100 mph).  And while they can be very maneuverable, they can also do very precise smooth maneuvering as well.

If there were some big custom multicopters used for air-snagging the parachute of a descending fairing half, I would expect that the single recovery barge (or ship with a very big deck) would be located at the sweet spot of where the fairings would likely splash down from their ballistic descent if they didn’t have chutes (not accounting for local wind variation). So, the multicopters would not have to travel too far horizontally, mainly climb to altitude, and then begin to home in on its assigned fairing/parachute.  Also, being designed to have the thrust to fly back with 1 ton underneath, it would be able to ascend crazy-fast without a payload (as well as fly very fast horizontally to catch-up to rendezvous for the air-snag maneuver).  After the snag,  not needing to fly very fast horizontally (mostly the issue of the drag and wobbling of fairing underneath while traveling horizontally). And ideally the whole thing would happen mostly directly above the barge (also thanks in part to the steerable parachute), so if the air-snag was say a mile up, it may have less than a mile to fly horizontally. 

This video (link below) by Casey Neistat gives info on the multicopter that was used for the Christmas video that he made.  16 motors, 16 props…..  a “HexaDecaCopter” (Hmm, with 8 x 2 layout I'd say more like a OctoCopter 2X, though I do get that hex + deca implies the number 16. An 8-armed multicopter  is called an OctoCopter).   By itself, it weighs 165 pounds. With Neistat, all the rigging, snowboard, total flying weight of about 365 pounds.  Max thrust of 1050 pounds. That info comes from this video he made about it:

https://www.youtube.com/watch?v=DyUrqZBs2XA&t=2s

It was made by three people, (two of whom are husband and wife) over a period of about a year. It is not known if they did this full-time as their one and only project, or a side project.  It is described as “home made”. So I suspect it was done as a side project. I suspect that if they were a small “mom and pop and friend” company that had the $ and time to do nothing else but this, they could have done it in far less time. Just as a hobbyist I may have a project that takes me 6 months to get done…. but that does not mean I put in 40 hours a week on it for 6 months, it’s a side project.  I do wish I knew more about them. Whoever they are, he trusted his life to them. For anyone who does not watch the whole thing, for the flying scenes he wore a harness with a cable running up one arm, hooked to the copter,  not just holding on by one hand.

One company that has made a “sit inside” passenger Multicopter prototype is Volocopter:

http://volocopter.com/index.php/en/

No CGI  and no photoshop stuff here,  their prototype really does exist and flies (youtube videos). I’m not suggesting that SpaceX would buy two of these and modify them, as for one they are probably not big enough to have enough thrust to handle a fairing half. But as an example of a yet larger configuration that actually does exist. It has 18 motors & props (thrust could be nearly doubled if it also had a lower set of motors/props  under the upper ones as the one Niestat used has, at a cost of about half the duration for the same battery. Still probably not quite enough thrust). So this generic multicopter scale-up of a scale-up could be….. scaled-up.  And we know SpaceX ain’t afraid of flying vehicles that have dozens of clustered motors…… :)

So, I do not expect they will do this. But it has potential. I do think that such a  one ton cargo carrying multicopter will exist someday.  Just a matter of how soon some company (or military branch) can justify doing it and make it happen.
Title: Re: Fairing reuse
Post by: bstrong on 03/25/2017 06:47 PM
And don't forget that Elon's buddy Larry Page has not one, but two separate VTOL electric aircraft companies.

https://electrek.co/2016/10/25/first-picture-of-what-is-believed-to-be-larry-pages-electric-vtol-aircraft/
Title: Re: Fairing reuse
Post by: Lar on 03/26/2017 11:05 AM
Referring to fate seems to indicate something experimental.

Relaunch of a first stage is experimental.
It's almost like you and iamlucky13 have no idea of who Musk is. When Musk is given an opportunity to double down, he does. No way he's just a referring to reflying a stage.

His ENTIRE CAREER has been one big giant parlay. So far he's been winning (and we all benefit).  That's off topic but I wanted to throw it out there. Because, ya, to Elon, this reuse is already routine, IMHO.

I don't think the "fate" comment applies to fairing reuse, unless we fanspies really blew it, as there isn't any gear on the "fairing" ship to speak of yet. I think it's the Xoomba, but we'll find out soon enough.
Title: Re: Fairing reuse
Post by: intrepidpursuit on 03/26/2017 02:22 PM
My original post implied that stage reuse was not experimental. They can't consider it very experimental since they have a paying customer's payload on top. No, Elon has something else planned, and I don't think the roomba is exciting enough to be it.
Title: Re: Fairing reuse
Post by: Robotbeat on 03/26/2017 02:35 PM
My original post implied that stage reuse was not experimental. They can't consider it very experimental since they have a paying customer's payload on top. No, Elon has something else planned, and I don't think the roomba is exciting enough to be it.
The Roomba is pretty dang exciting, because Musk probably wants to use it or things like it to do more crazy things. And they need to do similar crazy things on Mars.

Smart money is on the Roomba. Optimus Prime.
Title: Re: Fairing reuse
Post by: LouScheffer on 03/26/2017 02:56 PM
Considering the technical problem only, and not cost, it seems like this is entirely feasible with existing technology.

(a) Fairing deploys a parachute.  There are many that can handle such loads (2 tonnes for a fairing half?)

(b) Two helicopters, taking off from a ship, catch the parachutes.  There are plenty of helicopters (not even the largest ones) that can handle this load (say Mi-8/Mi-17).  Range is not a problem since the ship is close to where the fairing comes down.

(c) The helicopters lower the fairings onto large airbags on the deck of a ship.  An internet search shows 15x15m airbags are stock items.  This should be gentle enough to not damage the fairing, and it never gets wet.

So now we have a working scheme, so the problem is to reduce the cost.  Perhaps they could put the airbags on the ASDS, and bring the fairings back with the booster.   Perhaps the helicopters can go out on the ASDS, take off before the booster lands, catch the fairings, then return to land unladen (the ferry range would indicate this might be possible.  Bahamas are about 400 km from landing zone.  Ferry range is close to 1000 km.   So the helicopter could use half its fuel making the catch, and still have enough to get to shore.).

Anyway, at an estimated cost of $3M per fairing, costs could be quite high and still worthwhile.

EDIT:  Added range to Bahamas, and ferry range.
Title: Re: Fairing reuse
Post by: Lar on 03/26/2017 09:41 PM
Sorry for being diversionary but let's stick to fairing reuse here, not what the big surprise is. Mea culpa.
Title: Re: Fairing reuse
Post by: Johnnyhinbos on 03/26/2017 09:54 PM
Humm - I'm going to be on a research vessel off Bimini, departing Miami April 3. I'll have to keep an eye out...
Title: Re: Fairing reuse
Post by: Robotbeat on 03/27/2017 12:21 AM
A K-max helicopter should be capable of capturing the fairing half. It's $5m, plus operations. But they're relatively affordable to operate. If based from an ASDS, they wouldn't need to fly much.

But I think SpaceX could build their own, short-range electric drone capable of capturing a fairing half for about $1 million.
Title: Re: Fairing reuse
Post by: Jet Black on 03/27/2017 11:28 AM
Referring to fate seems to indicate something experimental.

iirc this next launch is pretty far out on the edge of the envelope for a successful landing - where I include the rocket still being useable in successful.
Title: Re: Fairing reuse
Post by: CraigLieb on 03/27/2017 03:10 PM
We are beginning to see the designs of Elon, the evil genius...  (pinkie firmly planted in corner of mouth)

The fairing will deploy cold-gas thrusters and small pop-out grid fins to stabilize into a flyable aeroshell, navigating to a selected capture zone. At which point, the very large airship will open up it's large under slung cargo hold and the fairings will fly in and be caught in nets. The airship will then make its way to Elon's secret volcano lair ... which opens up it's hidden landing pad area, etc. Submarines or fast boats will return the shells to shore for additional processing.

 8)

 
Title: Re: Fairing reuse
Post by: oiorionsbelt on 03/27/2017 07:39 PM
A K-max helicopter should be capable of capturing the fairing half. It's $5m, plus operations. But they're relatively affordable to operate. If based from an ASDS, they wouldn't need to fly much.

But I think SpaceX could build their own, short-range electric drone capable of capturing a fairing half for about $1 million.
Or the fairing half is the drone.
Title: Re: Fairing reuse
Post by: georgegassaway on 03/27/2017 10:03 PM
Or the fairing half is the drone.

I actually considered that idea.  But the added mass of the motors, props, various other hardware (including deployment mechanisms), and especially the batteries, would likely be so much that it would impact either the payload mass to orbit or reduce the orbit for the same payload mass. That presumes not short-changing the core's fuel to land itself, by burning a bit longer to make up for the performance hit of heavier shrouds.

Of course, adding a steerable chute also adds SOME mass too. Gut feeling is that it would be way less extra mass than a "Transformer" Shroud-Drone, but must admit I don't have a good mass estimate for what it would take.
Title: Re: Fairing reuse
Post by: RobLynn on 03/27/2017 10:48 PM
A K-max helicopter should be capable of capturing the fairing half. It's $5m, plus operations. But they're relatively affordable to operate. If based from an ASDS, they wouldn't need to fly much.

But I think SpaceX could build their own, short-range electric drone capable of capturing a fairing half for about $1 million.
Or buy 6x robinson R22s or R44s for abut $2-3 million (less than a single k-max), implement autonomous control on them, and adapt the software these guys made to catch the falling fairing halves:
https://www.youtube.com/watch?v=oDyfGM35ekc?t=67

The helicopters can use long ropes to be 100's of meters away from the falling fairings, the nets can be pretty big so less precision is required, the net impacts can be very gentle, and apart from whatever modifications are needed to successfully re-enter almost no other add-ons or controls are needed on the fairings.
Title: Re: Fairing reuse
Post by: Robotbeat on 03/28/2017 03:56 AM
More complicated, tho. I think they'd prefer to roll their own drone or use autonomous (or piloted, I suppose) K-Maxes.
Title: Re: Fairing reuse
Post by: Kaputnik on 03/28/2017 06:56 AM
Zero evidence for this, but splitting the fairing into four would simplify things a fair bit.
Title: Re: Fairing reuse
Post by: matthewkantar on 03/28/2017 07:24 AM
Zero evidence for this, but splitting the fairing into four would simplify things a fair bit.

The washering, flanging, and hardware for the joint adds a lot of weight.
Title: Re: Fairing reuse
Post by: Kaputnik on 03/28/2017 12:07 PM
Zero evidence for this, but splitting the fairing into four would simplify things a fair bit.

The washering, flanging, and hardware for the joint adds a lot of weight.

Fair point. I can't t think of any LVs that use anything other than a two part clamshell.
Title: Re: Fairing reuse
Post by: cscott on 03/28/2017 12:11 PM
Zero evidence for this, but splitting the fairing into four would simplify things a fair bit.
What's your reasoning?

It seems to me it would just multiply the complexity: four avionics packages, four parafoils, four joints, four ASDSes, four helicopters, four airbags, etc.

In fact, some folks spent a lot of time upthread trying to figure out how to reattach the fairing halves after separation to create *one* flyback item.  That also adds a lot of complexity.

Seems like two halves is the sweet spot.  But I'm interested to hear why you think four is better.
Title: Re: Fairing reuse
Post by: Robotbeat on 03/28/2017 12:14 PM
Two halves connected by a huge hinge? 😂
Title: Re: Fairing reuse
Post by: Confusador on 03/28/2017 12:16 PM
Two halves connected by a huge hinge? 😂

That was the idea, yes, from the very first page of this thread.  I think it's been done to death at this point.

Edit for clarity: I suspect Robotbeat remembers that, and is joking. But I don't want that to accidentally encourage anyone...
Title: Re: Fairing reuse
Post by: rsdavis9 on 03/28/2017 12:44 PM
Zero evidence for this, but splitting the fairing into four would simplify things a fair bit.
What's your reasoning?

It seems to me it would just multiply the complexity: four avionics packages, four parafoils, four joints, four ASDSes, four helicopters, four airbags, etc.

In fact, some folks spent a lot of time upthread trying to figure out how to reattach the fairing halves after separation to create *one* flyback item.  That also adds a lot of complexity.

Seems like two halves is the sweet spot.  But I'm interested to hear why you think four is better.

Each piece is lighter and easier to "catch"?

I personally like barge with "fall bag" or basically large inflatable dome material.
Title: Re: Fairing reuse
Post by: Welsh Dragon on 03/28/2017 01:01 PM
Zero evidence for this, but splitting the fairing into four would simplify things a fair bit.

The washering, flanging, and hardware for the joint adds a lot of weight.

Fair point. I can't t think of any LVs that use anything other than a two part clamshell.
Pretty sure some Titans used three part fairings.
Title: Re: Fairing reuse
Post by: MP99 on 03/28/2017 06:53 PM
Two halves connected by a huge hinge? 😂

Make them flap, and you'd have an ornithopter!!  BFG.

Cheers, Martin

Title: Re: Fairing reuse
Post by: Jim on 03/28/2017 08:23 PM
Zero evidence for this, but splitting the fairing into four would simplify things a fair bit.

The washering, flanging, and hardware for the joint adds a lot of weight.

Fair point. I can't t think of any LVs that use anything other than a two part clamshell.

Titan IV, Titan III, Delta II 10 metal, Skylab
Title: Re: Fairing reuse
Post by: cscott on 03/28/2017 08:42 PM
Didn't Apollo also have a four-part fairing around the LEM?
Title: Re: Fairing reuse
Post by: nacnud on 03/28/2017 08:46 PM
Yep
Title: Re: Fairing reuse
Post by: iamlucky13 on 03/28/2017 11:28 PM
Referring to fate seems to indicate something experimental.

Relaunch of a first stage is experimental.
It's almost like you and iamlucky13 have no idea of who Musk is. When Musk is given an opportunity to double down, he does. No way he's just a referring to reflying a stage.

When has he doubled down as you suggest?

Maybe I'm confused about who Musk is, but I'm fairly certain he's proud of his businesses and can't resist talking about them. When he's got something up his sleeve, he's generally dropped clear hints he's got something up his sleeve. He wants you paying attention for the punchline, not turning off the stream once the rocket touches down, so you miss the fairing landing.

Two make two more specific comments: using a fancy peace of ground support equipment to assist with recovery after the hard part is over is not fateful.

Successfully recovering a fairing is arguably fateful, but not nearly to the same degree as proving he really can refly rocket stages. Reflying a rocket stage is significant enough there's no reason to ascribe comments about fate to anything else unless Musk acts like Musk usually does and gives you a clear reason.

I have other reasons for expecting they will probably not be recovering a fairing this launch, but I'm not able to discuss them at this time.
Title: Re: Fairing reuse
Post by: cscott on 03/29/2017 01:12 AM
This will be a very hot landing, but if it comes back, SES gets "bits" for their boardroom.

The hot landing probably explains Elon's "fate" tweet from last week, then.  Maybe a three-engine landing burn again, and they've never yet only once been successful with that.

EDIT: from the launch log (http://forum.nasaspaceflight.com/index.php?topic=40544.msg1550541#msg1550541), only 4 attempts at multi-engine burns:
SES-9: 3-engine burn, unsuccessful.
JCSAT-14: 3-engine burn, successful.
Thaicom-8: 1-3-1 burn, successful. (Not a 3-engine *landing* burn AIUI.)
Eutelsat 117W: 3-engine burn, unsuccessful.

This landing is apparently "hot".  SES-9 was a 3-engine landing burn that took out OCISLY from space.  "Fate" could be simply referring to the narrow-margin landing attempt on this launch.

I hope OCISLY's clover is working!
Title: Re: Fairing reuse
Post by: Robotbeat on 03/29/2017 01:12 AM
It's not fairing recovery I think he'll be talking about, but our roomba friend. My main point has always been that the thing he's referring to in the tweet is not just reuse of the first stage.
Title: Re: Fairing reuse
Post by: Semmel on 03/29/2017 06:29 AM
My main point has always been that the thing he's referring to in the tweet is not just reuse of the first stage.

I am pretty sure it is first stage reuse. It's the one thing that is disruptive of the launch industry. It's the one thing the success of SpaceX will hinge on. I mean not this flight particularly but reuse in general. This flight is the first occasion where proving reuse is possible and maybe even economic. Any other technical challenge like fairing reuse will not determine SpaceXs future. But reuse must work or SpaceX has failed. That's why (in my opinion) musk is talking about fate.
Title: Re: Fairing reuse
Post by: john smith 19 on 03/29/2017 06:38 AM
I associate a "hot" landing with a stage that has pushed the rest of the stack to higher velocity or altitude than usual missions.

It will therefor be coming in at a faster velocity. OTOH it had to burn harder on launch suggests it will also have tighter restrictions on how much landing propellant it can carry.

So propellant margins are tight and the terminal landing process is shorter than usual. That means this time round engines really need to start at the first attempt and burn at full planned thrust for the full duration. It's unlikely the landing legs can soak up much of the KE left if the engines do their part fully.

All of which will make for very exciting video.
Title: Re: Fairing reuse
Post by: john smith 19 on 03/29/2017 06:41 AM
TBH I've never really understood need for the very rigid, heavy fairings that LV's use.

I've often wondered if you could get by with an inflatable design, soft of like those emergency half circular shelters, but with two edge to edge and both on end.
Title: Re: Fairing reuse
Post by: Kaputnik on 03/29/2017 11:36 AM
TBH I've never really understood need for the very rigid, heavy fairings that LV's use.

I've often wondered if you could get by with an inflatable design, soft of like those emergency half circular shelters, but with two edge to edge and both on end.

 Seriously? For max Q, we're talking around mach 1 and airliner cruising altitude. That's a pretty tough gig. I don't see too many inflatable supersonic aircraft going about.
Title: Re: Fairing reuse
Post by: john smith 19 on 03/29/2017 01:05 PM
TBH I've never really understood need for the very rigid, heavy fairings that LV's use.

I've often wondered if you could get by with an inflatable design, soft of like those emergency half circular shelters, but with two edge to edge and both on end.

 Seriously? For max Q, we're talking around mach 1 and airliner cruising altitude. That's a pretty tough gig. I don't see too many inflatable supersonic aircraft going about.
The difference between launch and cruise.  During launch dynamic pressure is quoted in pounds per sq foot because the rise in terms of psi (IE 1/144 smaller) is pretty small. I could see the need for a rigid fairing if there is a real fear of impact damage to the outside of the payload or if the fairing has inside ties to the payload to keep in place. 

The former is a real threat but the latter is not done AFAIK, even for payloads that require "vertical launch" due to the fragility of some of their components.

A lot of common practice in this industry seems to have evolved during the development of ICBMs.

I'd also point out that Joseph Kittinger and Felix Baumgarntner have gone supersonic in free fall inside nothing but a flexible sack (or "pressure suit" as I like to call it   :)  ).

Rigid nose cones assured the aerodynamics and their weight was acceptable. But LV's don't sit in silos for decades with staff walking around them periodically for inspection that might damage their payloads by dropping tools on them. The best way to protect a payload is inside a vehicle assembly building, followed by a transfer to the pad and a launch ASAP.

The two issues I can see are the very high noise levels and maintaining a controlled environment, which means making it pressure tight to slightly above atmospheric pressure.

Very little in this industry is original so I'd love to find some NASA report from the 1960's that looked at this and explains why it's unrealistic but so far all I've found is a brief discussion from 2015.

Title: Re: Fairing reuse
Post by: Kaputnik on 03/29/2017 05:21 PM
The notion that we only see PLFs because that's what works for an ICBM seems a bit unrealistic. I'm sure the question of payload fairing mass, and how to reduce it, has been given at least *some* consideration by aerospace engineers over the last five decades.

But let's consider an inflatable fairing. It would be a pressure-stabilised structure, which we know works well on tankage. However propellant is incompressible so you can fairly pump up the tank pressure. A payload designed to operate in a vacuum would need to also be rated for the pressure of the inflated fairing (assuming a single skin structure). This pressure would be whatever max-Q is plus whatever is needed to make the PLF completely rigid and aerodynamically stable. That's got to be a fair bit of pressure...
Title: Re: Fairing reuse
Post by: Jim on 03/29/2017 05:37 PM
A lot of common practice in this industry seems to have evolved during the development of ICBMs.


Wrong, single warhead ICBM's have no need for fairings
Title: Re: Fairing reuse
Post by: Jim on 03/29/2017 05:40 PM
I could see the need for a rigid fairing if there is a real fear of impact damage to the outside of the payload or if the fairing has inside ties to the payload to keep in place. 


Neither are applicable.
Title: Re: Fairing reuse
Post by: matthewkantar on 03/29/2017 05:45 PM
Having to be rated for pressure would seem less consequential than having to be rated for rapid decompression. Fairings let the pressure drop as the rocket climbs. With an inflatable fairing, you would need to maintain the correct pressure differential until the faring is unneeded, then figure out how to get rid of it in a reliable way, not by popping it like a balloon. The valving problem seems doable if problematic. The disposal part less so.

I suppose an inflatable fairing could be an envelope that is inflated, leaving the resulting cavity at ambient pressure. It could have two halves that meet at rigid frames and separate as normal, but any weight savings start to disappear with rigid structure, hardware, and two layers of material.

Matthew

edit, fixed typo, 3.29.17 1:49 edt
Title: Re: Fairing reuse
Post by: Jim on 03/29/2017 05:46 PM

I've often wondered if you could get by with an inflatable design,

Not viable.  See elsewhere in the forum as to why.
Title: Re: Fairing reuse
Post by: whitelancer64 on 03/29/2017 06:00 PM
TBH I've never really understood need for the very rigid, heavy fairings that LV's use.

I've often wondered if you could get by with an inflatable design, soft of like those emergency half circular shelters, but with two edge to edge and both on end.

 Seriously? For max Q, we're talking around mach 1 and airliner cruising altitude. That's a pretty tough gig. I don't see too many inflatable supersonic aircraft going about.
The difference between launch and cruise.  During launch dynamic pressure is quoted in pounds per sq foot because the rise in terms of psi (IE 1/144 smaller) is pretty small. I could see the need for a rigid fairing if there is a real fear of impact damage to the outside of the payload or if the fairing has inside ties to the payload to keep in place. 

The former is a real threat but the latter is not done AFAIK, even for payloads that require "vertical launch" due to the fragility of some of their components.

A lot of common practice in this industry seems to have evolved during the development of ICBMs.

I'd also point out that Joseph Kittinger and Felix Baumgarntner have gone supersonic in free fall inside nothing but a flexible sack (or "pressure suit" as I like to call it   :)  ).

Rigid nose cones assured the aerodynamics and their weight was acceptable. But LV's don't sit in silos for decades with staff walking around them periodically for inspection that might damage their payloads by dropping tools on them. The best way to protect a payload is inside a vehicle assembly building, followed by a transfer to the pad and a launch ASAP.

The two issues I can see are the very high noise levels and maintaining a controlled environment, which means making it pressure tight to slightly above atmospheric pressure.

Very little in this industry is original so I'd love to find some NASA report from the 1960's that looked at this and explains why it's unrealistic but so far all I've found is a brief discussion from 2015.

Fairings do several things to protect the payload. They protect against environmental hazards, as well as thermal, aerodynamic, noise, and EM stresses. Environmental and thermal is very important during the sit on the pad, which could be for several days in varying weather conditions, but could also be helpful during launch, if there's flight through a cloud, or a bird strike. Aerodynamic and noise during launch - as noted, Max Q is almost always supersonic and still well within the stratosphere. If there's an airplane with inflatable leading wing edges that can go supersonic, I'd love to know about it. EM conditions can vary during launch and on the pad, but the most extreme would be a lightning strike - the EM forces must be diverted so the payload isn't harmed.

Inflatable is just not going to cut it for any of these functions.
Title: Re: Fairing reuse
Post by: SLC on 03/29/2017 11:21 PM
TBH I've never really understood need for the very rigid, heavy fairings that LV's use.

I've often wondered if you could get by with an inflatable design, soft of like those emergency half circular shelters, but with two edge to edge and both on end.

 Seriously? For max Q, we're talking around mach 1 and airliner cruising altitude. That's a pretty tough gig. I don't see too many inflatable supersonic aircraft going about.
The difference between launch and cruise.  During launch dynamic pressure is quoted in pounds per sq foot because the rise in terms of psi (IE 1/144 smaller) is pretty small. I could see the need for a rigid fairing if there is a real fear of impact damage to the outside of the payload or if the fairing has inside ties to the payload to keep in place. 

The former is a real threat but the latter is not done AFAIK, even for payloads that require "vertical launch" due to the fragility of some of their components.

A lot of common practice in this industry seems to have evolved during the development of ICBMs.

I'd also point out that Joseph Kittinger and Felix Baumgarntner have gone supersonic in free fall inside nothing but a flexible sack (or "pressure suit" as I like to call it   :)  ).

Rigid nose cones assured the aerodynamics and their weight was acceptable. But LV's don't sit in silos for decades with staff walking around them periodically for inspection that might damage their payloads by dropping tools on them. The best way to protect a payload is inside a vehicle assembly building, followed by a transfer to the pad and a launch ASAP.

The two issues I can see are the very high noise levels and maintaining a controlled environment, which means making it pressure tight to slightly above atmospheric pressure.

Very little in this industry is original so I'd love to find some NASA report from the 1960's that looked at this and explains why it's unrealistic but so far all I've found is a brief discussion from 2015.

Fairings do several things to protect the payload. They protect against environmental hazards, as well as thermal, aerodynamic, noise, and EM stresses. Environmental and thermal is very important during the sit on the pad, which could be for several days in varying weather conditions, but could also be helpful during launch, if there's flight through a cloud, or a bird strike. Aerodynamic and noise during launch - as noted, Max Q is almost always supersonic and still well within the stratosphere. If there's an airplane with inflatable leading wing edges that can go supersonic, I'd love to know about it. EM conditions can vary during launch and on the pad, but the most extreme would be a lightning strike - the EM forces must be diverted so the payload isn't harmed.

Inflatable is just not going to cut it for any of these functions.
Then again, NASA seems quite serious about HIAD inflatable heat-shields for atmospheric entry - see the two references quoted in the Wikipedia NASA HIAD paragraph here:

http://en.wikipedia.org/wiki/Atmospheric_entry#NASA_HIAD

If a re-entry heat-shield can be made inflatable, why not a fairing?
Title: Re: Fairing reuse
Post by: Jim on 03/30/2017 12:16 AM

If a re-entry heat-shield can be made inflatable, why not a fairing?

It isn't a whole heat heat, it is only the parameter and it is not protecting anything in the interior.
Title: Re: Fairing reuse
Post by: Jim on 03/30/2017 12:30 AM

Random max q number of 1000 psf.

typical fairing frontal area 200 sq ft.

so, what inflatable tube of 50 ft or so can support 100 tons.

Now add in a slight angle of attack which:
a.  increases the frontal area
b.  induces bending forces.
c. while still maintaining a dynamic envelope of a few inches.
Title: Re: Fairing reuse
Post by: Robotbeat on 03/30/2017 02:40 AM
I think you could build an inflatable fairing if you pumped it to a high enough pressure, but why? It's dumb. Separation is actually more complicated. The payload now has to handle higher than Earth pressure. It's now a pad hazard as it could pop. It probably is worse acoustically as well.

I think you could definitely build an inflatable tube to hold 50-100 tons. But it's a terrible idea.
Title: Re: Fairing reuse
Post by: LouScheffer on 03/30/2017 04:40 AM

Random max q number of 1000 psf.

typical fairing frontal area 200 sq ft.

so, what inflatable tube of 50 ft or so can support 100 tons.

Atlas balloon tank.
Title: Re: Fairing reuse
Post by: guckyfan on 03/30/2017 10:39 AM
Atlas ballon tank is not inflatable.
Title: Re: Fairing reuse
Post by: Johnnyhinbos on 03/30/2017 11:02 AM
Ok, I'm not jumping on the inflatable fairing bandwagon, but I do want to point out that perhaps when posters refer to an inflatable fairing they aren't referring to an outer shell that encapsulates the payload and the entire volume is pumped up to desired pressure for rigidity, but rather an inflatable fairing would be, say, two parts just like a traditional SpaceX fairing, but each half has an outer and an inner wall so that only the fairing itself is pressurized. It would still have the same bulkhead fittings for HVAC etc, the same vents to allow the payload to equalize to ambient pressure, etc.

The perceived benefits would be weight, possible cost, and possibly the halves would be easier to recover.

Boosting this hollow shell to required stiffness pressure isn't that hard, requires much less gas, and stiffness increases with height (though no doubt a pressure relief valve is required to prevent overpressure events.)

Materiel science and tech have come a long way and I'd say this concept is definitely solvable if desired.

But again, just making a point. Not stating my personal opinion.
Title: Re: Fairing reuse
Post by: Lar on 03/30/2017 11:15 AM
SpaceX optimize for cost. Not PMF, not anything else. Cost.

I'm not seeing how an inflatable fairing, even if it could be made to work, makes recovery easier, or costs so much less that it can be discarded without concern like the blisterpack on your next phone charger cable[1]... Even if you could figure out how to discard (separate) cleanly.

I mean, I see paths to solving many of these problems. But no reason to do so. Rigid fairings are going to fly better once separated anyway.

1 - there are movements afoot to get rid of blisterpacks in favor of reusable packaging but you know what I mean.
Title: Re: Fairing reuse
Post by: Kaputnik on 03/30/2017 11:20 AM
This inflatable fairing thing is like beating a dead horse.
Single skin: too much pressure on the payload
Double skin: you lose all the weight advantages

There must be realistic methods of reducing fairing weight. E.g. a weaker fairing connected to a load bearing pathway through the payload (trade payload mass for fairing mass). Or a single piece fairing with a higher risk jettison manoeuvre. Or reduced fairing size to cater for smaller payload, trading higher manufacturing costs and multiple configurations for slight weight loss.
Title: Re: Fairing reuse
Post by: Lar on 03/30/2017 12:03 PM
This inflatable fairing thing is like beating a dead horse.
Single skin: too much pressure on the payload
Double skin: you lose all the weight advantages

There must be realistic methods of reducing fairing weight. E.g. a weaker fairing connected to a load bearing pathway through the payload (trade payload mass for fairing mass). Or a single piece fairing with a higher risk jettison manoeuvre. Or reduced fairing size to cater for smaller payload, trading higher manufacturing costs and multiple configurations for slight weight loss.

I'm sure there are.  Let ULA pursue them. SpaceX optimizes for cost. Not weight. It so happens that a high PMF often reduces cost, but it's not the goal per se...
Title: Re: Fairing reuse
Post by: Jim on 03/30/2017 01:35 PM

Random max q number of 1000 psf.

typical fairing frontal area 200 sq ft.

so, what inflatable tube of 50 ft or so can support 100 tons.

Atlas balloon tank.

That is at 30 to 40 psi and did not separate
Title: Re: Fairing reuse
Post by: john smith 19 on 03/30/2017 02:29 PM
I'm sure there are.  Let ULA pursue them. SpaceX optimizes for cost. Not weight. It so happens that a high PMF often reduces cost, but it's not the goal per se...
That's a fair point .

Turning the question on its head how much mass does making the opening mechanism reclosable add to the current design. In fact what does a current PLF for the F9 weigh? I'm guessing several tonnes.
Title: Re: Fairing reuse
Post by: Jim on 03/30/2017 02:36 PM

There must be realistic methods of reducing fairing weight. E.g. a weaker fairing connected to a load bearing pathway through the payload (trade payload mass for fairing mass).

That isn't realistic.  Fairing mass is not a one to one ratio with payload mass.
Title: Re: Fairing reuse
Post by: meekGee on 03/30/2017 04:28 PM
This inflatable fairing thing is like beating a dead horse.
Single skin: too much pressure on the payload
Double skin: you lose all the weight advantages

There must be realistic methods of reducing fairing weight. E.g. a weaker fairing connected to a load bearing pathway through the payload (trade payload mass for fairing mass). Or a single piece fairing with a higher risk jettison manoeuvre. Or reduced fairing size to cater for smaller payload, trading higher manufacturing costs and multiple configurations for slight weight loss.
The central pillar is exactly what I was thinking for the fairings of the comsats deployers, since you already have the dispenser spine in place.

You could even take it a step further, with radial support, and remove most of the structural demand on the fairing.
Title: Re: Fairing reuse
Post by: MikeAtkinson on 03/30/2017 04:36 PM
This inflatable fairing thing is like beating a dead horse.
Single skin: too much pressure on the payload
Double skin: you lose all the weight advantages

There must be realistic methods of reducing fairing weight. E.g. a weaker fairing connected to a load bearing pathway through the payload (trade payload mass for fairing mass). Or a single piece fairing with a higher risk jettison manoeuvre. Or reduced fairing size to cater for smaller payload, trading higher manufacturing costs and multiple configurations for slight weight loss.
The central pillar is exactly what I was thinking for the fairings of the comsats deployers, since you already have the dispenser spine in place.

You could even take it a step further, with radial support, and remove most of the structural demand on the fairing.

But that central pillar would then go all the way to orbit, wouldn't it? So might not end up being a net win, even for LEO, unlikely to be a net win for GTO.
Title: Re: Fairing reuse
Post by: meekGee on 03/30/2017 04:42 PM
This inflatable fairing thing is like beating a dead horse.
Single skin: too much pressure on the payload
Double skin: you lose all the weight advantages

There must be realistic methods of reducing fairing weight. E.g. a weaker fairing connected to a load bearing pathway through the payload (trade payload mass for fairing mass). Or a single piece fairing with a higher risk jettison manoeuvre. Or reduced fairing size to cater for smaller payload, trading higher manufacturing costs and multiple configurations for slight weight loss.
The central pillar is exactly what I was thinking for the fairings of the comsats deployers, since you already have the dispenser spine in place.

You could even take it a step further, with radial support, and remove most of the structural demand on the fairing.

But that central pillar would then go all the way to orbit, wouldn't it? So might not end up being a net win, even for LEO, unlikely to be a net win for GTO.
It already does, and is already holding 10 tons of cantilevered satellites off of it, at high g.

Designing it to give support for the fairing would not add significant weight IMO, but would not only save fairing weight, but make it much easier to manufacture.

With less constraints, maybe also easier to recover and reuse.
Title: Re: Fairing reuse
Post by: Kaputnik on 03/30/2017 04:49 PM

There must be realistic methods of reducing fairing weight. E.g. a weaker fairing connected to a load bearing pathway through the payload (trade payload mass for fairing mass).

That isn't realistic.  Fairing mass is not a one to one ratio with payload mass.

I meant 'realistic compared to inflatable PLFs'. I'm not saying it's a good idea compared to what already happens.

If someone did think it was a good idea to pass fairing loads through the payload (or, more specifically, the dispenser), then you have to think of a way to reliably decouple that load for jettison, and also swallow the additional manufacturing and qualifying for a complete second PLF system (because not all payloads are going to be able to do this).
Title: Re: Fairing reuse
Post by: ChrisC on 03/30/2017 04:59 PM
Steve Jurvetson on Facebook (https://www.facebook.com/jurvetson/posts/10158475022955611) :

Quote from: Steve Jurvetson
At the historic Apollo 11 Pad 39A for the first reuse of a SpaceX booster (and first attempt at a fairing recovery). Go SpaceX and SES-10, go, go go!
Title: Re: Fairing reuse
Post by: cscott on 03/30/2017 05:06 PM
Confirmation!
Title: Re: Fairing reuse
Post by: Lar on 03/30/2017 05:11 PM
Steve Jurvetson on Facebook (https://www.facebook.com/jurvetson/posts/10158475022955611) :

Quote from: Steve Jurvetson
At the historic Apollo 11 Pad 39A for the first reuse of a SpaceX booster (and first attempt at a fairing recovery). Go SpaceX and SES-10, go, go go!

He probably has a better handle than most of us on this, since he is (from his FB page)....
- Board of Directors at SpaceX
- Board of Directors at Tesla
- Partner at DFJ

He didn't accept my friend request yet, oddly...

We've not seen a lot of signs of this being tested but maybe they did most of it out at sea. 

(just wow!)
Title: Re: Fairing reuse
Post by: Jarnis on 03/30/2017 05:23 PM
Must mean that the recovery gear doesn't weight much as this is a marginal mission for booster recovery to start with. Would've expected the next one (NROL) to be far more likely candidate due to the margins there since it is a RTLS.

Of course on SES-10 they have the SpaceX Flotilla out there already, while on a RTLS mission they would have to go out separately just for the fairing(s).
Title: Re: Fairing reuse
Post by: Toast on 03/30/2017 05:58 PM
Steve Jurvetson on Facebook (https://www.facebook.com/jurvetson/posts/10158475022955611) :

Quote from: Steve Jurvetson
At the historic Apollo 11 Pad 39A for the first reuse of a SpaceX booster (and first attempt at a fairing recovery). Go SpaceX and SES-10, go, go go!

Guess I get to eat my words then. Sounds like this will be an awesome launch!
Title: Re: Fairing reuse
Post by: Machdiamond on 03/30/2017 06:04 PM
When Musk tweeted a few days ago "If fate is on our side, it will be amazing", maybe this is what he was referring to.
Title: Re: Fairing reuse
Post by: NX-0 on 03/30/2017 06:53 PM
How fast is the fairing going when it splashes now? The shape creates some drag. How slow does a fairing have to be to withstand damage at splash?

Also, it's odd how, when I heard "inflatable," I was thinking something completely different than the rest of you.
Suppose that inside the fairing wall you installed a deflated "beach ball".
As the fairing tumbled and fell through the atmosphere, at some point, the beach ball would inflate. This would increase drag significantly.
At splash, it also makes it very buoyant. It just rides the waves until someone comes and gets it.
Title: Re: Fairing reuse
Post by: Kaputnik on 03/30/2017 07:20 PM
How fast is the fairing going when it splashes now? The shape creates some drag. How slow does a fairing have to be to withstand damage at splash?

Also, it's odd how, when I heard "inflatable," I was thinking something completely different than the rest of you.
Suppose that inside the fairing wall you installed a deflated "beach ball".
As the fairing tumbled and fell through the atmosphere, at some point, the beach ball would inflate. This would increase drag significantly.
At splash, it also makes it very buoyant. It just rides the waves until someone comes and gets it.

Except Gwynne Shotwell has explicitly stated that they will not be getting the fairings wet.
Title: Re: Fairing reuse
Post by: envy887 on 03/30/2017 07:21 PM
How fast is the fairing going when it splashes now? The shape creates some drag. How slow does a fairing have to be to withstand damage at splash?

Also, it's odd how, when I heard "inflatable," I was thinking something completely different than the rest of you.
Suppose that inside the fairing wall you installed a deflated "beach ball".
As the fairing tumbled and fell through the atmosphere, at some point, the beach ball would inflate. This would increase drag significantly.
At splash, it also makes it very buoyant. It just rides the waves until someone comes and gets it.

Musk said a while ago that they were going to try steerable parachutes, and Shotwell said a few weeks ago that they don't want to get the fairings wet.

Maybe they will have both an inflatable and a chute on the fairing, but I have a hard time seeing anything like that keeping it totally out of the water.
Title: Re: Fairing reuse
Post by: vanoord on 03/30/2017 07:31 PM
Just getting the thing down in one piece would be an achievement, even if it got wet at the end - that's how they started with F9.
Title: Re: Fairing reuse
Post by: Chris_Pi on 03/30/2017 07:33 PM
Musk said a while ago that they were going to try steerable parachutes, and Shotwell said a few weeks ago that they don't want to get the fairings wet.

Maybe they will have both an inflatable and a chute on the fairing, but I have a hard time seeing anything like that keeping it totally out of the water.

Don't think packing enough airbags into the fairing to make it it's own boat is practical, So:

Flyback to land - Probably can't cover the distance.

Landing on barge/ship - Needs to be pretty accurate and haven't seen anything other than the usual support ships, But a plain old deck cargo barge is all that's likely needed. Rent a couple for a week or so and throw some big airbags on top as cushions.

Mid-air snag with aircraft -  Not much anyone would know about publicly until a helicopter flies past trailing a fairing half behind. Wait and see.

Title: Re: Fairing reuse
Post by: CraigLieb on 03/30/2017 07:43 PM
I'm sticking with the airship with a cargo hold model till they tell me otherwise..
You KNOW he has to have a secret island somewhere too... right!
Title: Re: Fairing reuse
Post by: AncientU on 03/30/2017 08:14 PM
Secret Island is my bet, too.

Since so many eyes are on this launch, though, they might forego the real plan and snag the steerable gliders from a 'civilian' base in the Bahamas (Marsh Harbor).
Title: Re: Fairing reuse
Post by: vanoord on 03/30/2017 08:35 PM

Don't think packing enough airbags into the fairing to make it it's own boat is practical, So:

Not a thoroughly daft idea, but it might add 200kg to each fairing.

I reckon any decent inflatable boat / liferaft manufacturer would be able to make a deployable 'boat' that could be popped out from the outside of the fairing and rapidly inflated just before touchdown under parachute, but the weight gain might equate to the loss of the booster core. Which is less than ideal.

I'm also unconvinced that even with some sort of pop-out liferaft the fairing would remain dry in the sort of conditions we've seen stages land in.
Title: Re: Fairing reuse
Post by: john smith 19 on 03/30/2017 10:59 PM
I take it SX have not released a nifty little video of their plans. That is curiously shy of them :)

Well assuming you're going to do it I guess a key question would be do you want the segments together or apart?

Historically they've separated. Those segments don't look very stable so how do you stabilize them to minimize damage from high speed airflow. While the look sort of canoe shaped they are a canoe with  no back, so likely to be quite flimsy. Despite their high surface area they are still likely to be moving too fast to survive if they hit the water without something to slow them down.

Then how do you recover them? Mid air capture?  Helium balloon?

Title: Re: Fairing reuse
Post by: Kabloona on 03/30/2017 11:57 PM
Chris Gebhardt reporting pic of SES-10 fairing has been shown intact floating on ocean after splashdown.
Title: Re: Fairing reuse
Post by: Lars-J on 03/30/2017 11:59 PM
Chris Gebhart reporting fairing has been recovered.

 :o Cool!
Title: Re: Fairing reuse
Post by: Chris Bergin on 03/31/2017 12:00 AM
BREAKING news:  Payload fairing LANDED SUCCESSFULLY.  Fairing has thruster systems and steerable parachute.  Was just shown pic of intact fairing floating in ocean.

Wowzers.
Title: Re: Fairing reuse
Post by: Dao Angkan on 03/31/2017 12:25 AM
Wow! If they can ocean land succesfully then landing on an ocean based platform might seem plausible. What an awesome mission!
Title: Re: Fairing reuse
Post by: john smith 19 on 03/31/2017 12:46 AM
BREAKING news:  Payload fairing LANDED SUCCESSFULLY.  Fairing has thruster systems and steerable parachute.  Was just shown pic of intact fairing floating in ocean.

Wowzers.
Very impressive.

Does anyone have any idea what one of these fairing costs? IIRC they were made by a Swiss company, but I'm not sure if SX brought their mfg in house.
Title: Re: Fairing reuse
Post by: Dao Angkan on 03/31/2017 12:55 AM
In the press conference Musk said they'll try to land it on a "bouncy castle" (inflatable).
Title: Re: Fairing reuse
Post by: Dao Angkan on 03/31/2017 12:56 AM
BREAKING news:  Payload fairing LANDED SUCCESSFULLY.  Fairing has thruster systems and steerable parachute.  Was just shown pic of intact fairing floating in ocean.

Wowzers.
Very impressive.

Does anyone have any idea what one of these fairing costs? IIRC they were made by a Swiss company, but I'm not sure if SX brought their mfg in house.

In the press conference Musk said $6 million.
Title: Re: Fairing reuse
Post by: Lar on 03/31/2017 12:59 AM
So this pair of fairings (floating at sea) was perhaps analogous to the first F9 S1 that "landed" in the ocean... and perhaps we'll see more leased barges equipped for fairing recovery duty?

The SpaceX flotilla is going to need a flagship and an Admiral :)

Has anyone run calcs on the kg ratio? (1kg of S2 mass is one less kg of payload mass, but one kg of additional fairing mass is less than 1g of lost payload because the fairings are ejected early, but it's not the same ratio as S1 mass which is more like 10:1 I think?) Maybe I missed it?

Also ...  AFRS??? (Automated Fairing Recovery Ship)
Title: Re: Fairing reuse
Post by: Joel on 03/31/2017 01:06 AM
How far from the drone ship should one expect the fairing to splash down? With a reasonable glide ratio, could it splash down next to it?
Title: Re: Fairing reuse
Post by: john smith 19 on 03/31/2017 01:17 AM
In the press conference Musk said $6 million.
Interesting.

When Shotwell was talking about a fully reusable F9 she said they were looking to lower prices to about $6m

Obviously you can't do that if just the fairing replacement eats that up.  :(

With this as 10% of your retail price something will have to be done.

Title: Re: Fairing reuse/cost
Post by: Geron on 03/31/2017 01:19 AM
At my SpaceX tour it was explained that the fairings were very expensive and difficult to manufacture. It was either 3.5 or 7 million at that time. I'm not sure if 3.5 was for one clamshell or both.

It's possible the cost has dropped since then though...
Title: Re: Fairing reuse
Post by: virnin on 03/31/2017 01:33 AM
BREAKING news:  Payload fairing LANDED SUCCESSFULLY.  Fairing has thruster systems and steerable parachute.  Was just shown pic of intact fairing floating in ocean.

Wowzers.

Maybe this is what SES gets in their Board Room?  ;)  (Yes, that would need a really BIG board room!)
Title: Re: Fairing reuse
Post by: Lar on 03/31/2017 01:34 AM
Maybe this is what SES gets in their Board Room?  ;)  (Yes, that would need a really BIG board room!)

It's already got their logo on it... :)
Title: Re: Fairing reuse
Post by: chad1011 on 03/31/2017 01:37 AM
It would make on heck of a boardroom table....
Title: Re: Fairing reuse
Post by: TrevorMonty on 03/31/2017 01:38 AM
.
Title: Re: Fairing reuse
Post by: Dao Angkan on 03/31/2017 02:05 AM
In the press conference Musk said $6 million.
Interesting.

When Shotwell was talking about a fully reusable F9 she said they were looking to lower prices to about $6m

Obviously you can't do that if just the fairing replacement eats that up.  :(

With this as 10% of your retail price something will have to be done.

He also joked(?) about despite not designing the second stage to return that maybe they should attempt to anyway as nothing to lose. He can sound mischievous at times, but there's usually some basis to what he says, so maybe they'll start to experiment with the second stage?
Title: Re: Fairing reuse
Post by: ClayJar on 03/31/2017 02:06 AM
Maybe this is what SES gets in their Board Room?  ;)  (Yes, that would need a really BIG board room!)

It's already got their logo on it... :)

In the presser, Martin Halliwell laughed that it was the wrong half (with the American flag instead of SES's logo).  From the sound of it, the photo was of one half.  I wonder if they had recovery hardware on both halves or just on one half (for a control test from space down to a water landing).
Title: Re: Fairing reuse
Post by: Dao Angkan on 03/31/2017 02:12 AM
Musk following on from fairing recovery;

Quote
Then the only thing left is the upper stage. We didn't originally intend for Falcon 9 to have a reusable upper stage, but it might be fun to try a Hail Mary and you know, what's the worst thing that can happen? It blows up. You know, It blows up anyway.
Title: Re: Fairing reuse
Post by: manoweb on 03/31/2017 02:15 AM
I cannot express how excited I am for this dream that is becoming true. Fairing recovery! So many dismissed this idea as impossible, especially on this flight. I cannot wait to see images and know more details, but apparently what we know now is:
- thrusters
- automated parachutes
- in the future, some sort of floating structure to keep it dry
- we also know that it landed close enough to some support boat that they were able to shoot a picture of it about an hour from separation

I hope we will see soon what is the trajectory of the fairings during their descent.
Title: Re: Fairing reuse
Post by: Dao Angkan on 03/31/2017 02:18 AM
Maybe this is what SES gets in their Board Room?  ;)  (Yes, that would need a really BIG board room!)

It's already got their logo on it... :)

In the presser, Martin Halliwell laughed that it was the wrong half (with the American flag instead of SES's logo).  From the sound of it, the photo was of one half.  I wonder if they had recovery hardware on both halves or just on one half (for a control test from space down to a water landing).

That makes sense, no need to double the extra weight when you only need to bring one back to prove the feasibility.
Title: Re: Fairing reuse
Post by: rsdavis9 on 03/31/2017 02:27 AM
Did he really say bouncy house? I said that upthread a ways.
Title: Re: Fairing reuse
Post by: meekGee on 03/31/2017 02:28 AM
Maybe this is what SES gets in their Board Room?  ;)  (Yes, that would need a really BIG board room!)

It's already got their logo on it... :)

Very good observation there.  A no-brainer if you think about it.

EDIT:

... and if they got the wrong half, at least a bumper sticker: "The other half says SES on it"
Title: Re: Fairing reuse
Post by: ClayJar on 03/31/2017 02:34 AM
https://www.youtube.com/watch?v=jC3LQFpuzqs

Fairing recovery starts at 12:05 when a guy walks in and shows Elon the photo of the floating fairing.

Did he really say bouncy house? I said that upthread a ways.

14:16 "So, what we'll have is kinda like a bouncy castle for it to land on."
Title: Re: Fairing reuse
Post by: Galactic Penguin SST on 03/31/2017 02:40 AM
Do we know how intact the fairing is on the sea? If you check out the Chinese rockets threads you will see multiple examples of the fairing making back on land relatively intact, but I am sure no one will like to use them back.  ;)
Title: Re: Fairing reuse
Post by: Space Ghost 1962 on 03/31/2017 03:28 AM
Today's was a test of the concept. Soft landed a fairing half at a known location.

Ariane, Soyuz, and others have by accident recovered fairings mostly intact. The difference here is deterministic result with controlled flight and a means to direct recovery to a specific location.

Next time its done you get both fairings recovered and dry.

The best benefit of this success is that it will lower the time it will take to recover the cost of reuse, because the increment of payoff has grown.
Title: Re: Fairing reuse
Post by: CameronD on 03/31/2017 06:01 AM
Finally, Go Searcher has a trophy to bring home..  :)
Title: Re: Fairing reuse
Post by: darkenfast on 03/31/2017 06:30 AM
"Look, Ma!  I caught a big one!"
Title: Re: Fairing reuse
Post by: manoweb on 03/31/2017 07:05 AM
Anyway - has anybody seen this image with the landed fairing? Or was it only shown to Mr. E. Musk during the press conference and never shown to the public, yet?
Title: Re: Fairing reuse
Post by: Lars-J on 03/31/2017 07:27 AM
I guess the fairing landed, but was not recovered. (sunk before they could get to it?)
https://twitter.com/SpaceBrendan/status/847599001746644996
Quote
Brendan Byrne @SpaceBrendan
Musk: Correction, not recovered, but it was directed to a landing area. Will have "bouncy" castle soon.

Aha! So it looks like my guess that they will try to land it on an inflated surface was correct.  8)
Title: Re: Fairing reuse
Post by: john smith 19 on 03/31/2017 07:42 AM
Thinking about faring reuse raises some interesting questions.

Historically there seems to have been a fair bit of customizing on the fairing for each payload. Custom sized (and shaped) doors and access panels. Specialized fluid and electrical connectors and windows for RF and various optical wavelengths.  I think they've been a nice options-at-extra-cost addition to the basic launch service for all LV mfgs.

In principle any fairing could wrap any payload, since they all have basically the same interior, but those different fittings will change the mechanical properties a bit. Any given hole is a potential stress concentrator so increase the risk of failure.  There is also the issue that composite structures can suffer impact damage leading to 30% loss of strength with no visible damage (NASA COPV tests).

The upside is that not being a closed surface (more like 2 canoes with the tails chopped off) the two halves can absorb a lot of stress by flexing in a wide variety of modes during the re entry.

So the question is will SX continue the practice of customized PLF's, and if so do customers get to choose which ones are used.Likewise if they chose the "no special mods" option do they get a stock PLF, or just get the next one that's available, regardless of what fittings are on it, as it's good enough to do the job?

BTW
First attempted PLF recovery (but plenty of data collected)

First re-flight of booster stage

First ground test of a new nuclear reactor designed for space in 7 decades (Kilopower in November)

2017 is looking to be an exciting year.  With luck it will also see SLC 40 working again and the long awaited FH maiden flight.

Title: Re: Fairing reuse
Post by: Lars-J on 03/31/2017 07:53 AM
So the question is will SX continue the practice of customized PLF's, and if so do customers get to choose which ones are used.Likewise if they chose the "no special mods" option do they get a stock PLF, or just get the next one that's available, regardless of what fittings are on it, as it's good enough to do the job?

I don't think SpaceX customizes their PLF's. (unless I am mistaken) There is only one model available.
Title: Re: Fairing reuse
Post by: woods170 on 03/31/2017 09:36 AM
Thinking about faring reuse raises some interesting questions.

Historically there seems to have been a fair bit of customizing on the fairing for each payload. Custom sized (and shaped) doors and access panels.

SpaceX doesn't do customized fairings (yet). "Historically" applies to other LSP's.
Title: Re: Fairing reuse
Post by: Welsh Dragon on 03/31/2017 09:41 AM
So the question is will SX continue the practice of customized PLF's, and if so do customers get to choose which ones are used.Likewise if they chose the "no special mods" option do they get a stock PLF, or just get the next one that's available, regardless of what fittings are on it, as it's good enough to do the job?

I don't think SpaceX customizes their PLF's. (unless I am mistaken) There is only one model available.
I think the customisation here would be adding the recovery mods. So in a sense you'd have two models, with or without those mods.
Title: Re: Fairing reuse
Post by: rpapo on 03/31/2017 10:19 AM
I don't think SpaceX customizes their PLF's. (unless I am mistaken) There is only one model available.
"Any customer can have a car painted any color that he wants so long as it is black."  -- Henry Ford
Title: Re: Fairing reuse
Post by: Robotbeat on 03/31/2017 11:24 AM
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. 😂
Title: Re: Fairing reuse
Post by: john smith 19 on 03/31/2017 11:30 AM
Thinking about faring reuse raises some interesting questions.

Historically there seems to have been a fair bit of customizing on the fairing for each payload. Custom sized (and shaped) doors and access panels.

SpaceX doesn't do customized fairings (yet). "Historically" applies to other LSP's.
Interesting. I recalled both Orbital (for Pegasus) and ULA offering PLF mods for various services and assumed it was SOP for all LV mfgs.

Keeping them standardized let's them do a batch and allow them them to swap PLF's round if one is damaged.

I note it took them a year to re-fly a first stage. Obviously a PLF is simpler but they still need to recover one intact. AIUI they were only trying to recover one of the pair of segments. My guess would be their next attempt will be for both halves to get a full set.

This is clearly the start of a journey. I think they will want to accumulate quite a lot of PLF's before they start re-flying.

It's interesting to ask if this could have been done decades ago if anyone was prepared to do so, or if only the advent of small, powerful GNC hardware has allowed something this complex to be flown.
Title: Re: Fairing reuse
Post by: john smith 19 on 03/31/2017 11:35 AM
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. 😂
That suggests either an inflatable structure draped over the ADRS or an even bigger "crash mat" towed behind it.


Either is quite possible, provided you can deliver enough air flow to keep the structure a couple of psi above atmospheric.  It should (in principle) allow a smaller parachute on thePLF, which is clearly a good thing, given how close the PLF gets to orbit.
Title: Re: Fairing reuse
Post by: JamesH65 on 03/31/2017 11:49 AM
I'm assuming something along these lines

https://www.youtube.com/watch?v=j9QrKzLVujs

Title: Re: Fairing reuse
Post by: Jcc on 03/31/2017 12:03 PM
I'm assuming something along these lines

https://www.youtube.com/watch?v=j9QrKzLVujs

Yes, only considerably larger than a bus, and floating in the ocean. And probably they need 2 of them. Then, visit with a ship with a crane, pick them up and put them on the deck, deflate and retrieve the "bouncy castle". All in a day's work.

Maybe they stay close together with the ship. Not much danger to the crew if they stay sheltered when they land. Or, possibly already on the deck. If the ship is big enough, it can hold 2 bouncy castles.
Title: Re: Fairing reuse
Post by: rpapo on 03/31/2017 12:06 PM
Yes, only considerably larger than a bus, and floating in the ocean. And probably they need 2 of them. Then, visit with a ship with a crane, pick them up and put them on the deck, deflate and retrieve the "bouncy castle". All in a day's work.

Maybe they stay close together with the ship. Not much danger to the crew if they stay sheltered when they land. Or, possibly already on the deck. If the ship is big enough, it can hold 2 bouncy castles.
Since the fairing descends without a tail of flame, if the landing is reasonably accurate, it may be possible for the tender to be closer than the tugs are at present to the ASDS.
Title: Re: Fairing reuse
Post by: rsdavis9 on 03/31/2017 12:47 PM
I think 2 separate barges with air bags on deck for the landing. Maybe transfer after landing to one ship to make fast trip back to land. Could even keep barges out there instead of making trip back and forth withlong trip back with barge.
Title: Re: Fairing reuse
Post by: matthewkantar on 03/31/2017 01:21 PM
Is anyone else surprised the fairing sank? They were close enough to photograph it, they didn't have the gear to retrieve it? Also, isn't it filled with air pockets from the construction method? A sizable piece floated to the Bahamas not so long ago.

Matthew
Title: Re: Fairing reuse
Post by: AncientU on 03/31/2017 01:46 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. 😂

We're well past the laughing stage...

Quote
First they ignore you, then they laugh at you, then they fight you, then you win*.
-- Mahatma Gandhi

https://www.brainyquote.com/quotes/quotes/m/mahatmagan103630.html

* We are here.
Title: Re: Fairing reuse
Post by: sghill on 03/31/2017 01:50 PM
I fly paraplanes and paragliders. The control mechanism setup is be very easy and cheap for a steerable parachute (parafoil).

Parafoils use wing warping for heading changes and throttle or thermals for altitude changes. One servo with a capstan holding both control wires will provide perfect directional control. Pulling on one set of risers while  releasing the other set is how control is maintained. Pitch is mostly irrelevant with a parafoil, and altitude can be bled off by circling as needed. 

They can circle down and fly the shell halves back towards shore remotely for helicopter pickup just off the coast or airbag landing in the water (Elon's "bouncy house").  Or just land them right in the brush at LZ-1. They are going to want a fairly low glide ratio (like 2:1 or 3:1) because the huge surface area of the aeroshell half underneath that is also catching the wind.
Title: Re: Fairing reuse
Post by: Norm38 on 03/31/2017 02:03 PM
Of the next 4 launches, two are RTLS, two are expendable.  So OCISLY is going to be mighty bored with nothing to do.  So maybe they'll use it to land fairings on?
Title: Re: Fairing reuse
Post by: padrat on 03/31/2017 03:03 PM
So the question is will SX continue the practice of customized PLF's, and if so do customers get to choose which ones are used.Likewise if they chose the "no special mods" option do they get a stock PLF, or just get the next one that's available, regardless of what fittings are on it, as it's good enough to do the job?

I don't think SpaceX customizes their PLF's. (unless I am mistaken) There is only one model available.

There isn't really much customization done to the fairings. We're working towards keeping them very generic, obviously an advantage when you want to eventually reuse them. The goal, at least for the commercial customers, is to get to a basic universal design where the only differences are the logo and antenna setup. The most customization gets done to the payload adapter, of course. But yet, even those are surprisingly the same few basic setups (mostly)
Title: Re: Fairing reuse
Post by: cscott on 03/31/2017 03:11 PM
Is anyone else surprised the fairing sank? They were close enough to photograph it, they didn't have the gear to retrieve it? Also, isn't it filled with air pockets from the construction method? A sizable piece floated to the Bahamas not so long ago.

Matthew
We don't know exactly what the photo was: it's possible it was a "chutes out but not yet in contact with ocean" shot from a considerable distance, like we get of dragon recovery.  The fairing could easily have broken apart on contact w the ocean surface, plus night was falling so it could be difficult to find the pieces once the recovery ship gets to the last known position, in darkness.

I bet they've got good video/telemetry, though, so they should know exactly what happened, how close they got to their aim point, etc.
Title: Re: Fairing reuse
Post by: launchwatcher on 03/31/2017 03:15 PM
Thinking about faring reuse raises some interesting questions.

Historically there seems to have been a fair bit of customizing on the fairing for each payload. Custom sized (and shaped) doors and access panels.

SpaceX doesn't do customized fairings (yet). "Historically" applies to other LSP's.
In 2015 at least they offered a little bit of customization.   The user guide says:
Quote
The fairing can accommodate up to two access doors in the cylindrical portion as a standard service. The
standard payload fairing door is elliptical, with a maximum size of 450 x 550 mm (17.7 x 21.7 in.).

Through-fairing RF antenna (re-radiation) systems are available as a nonstandard service; they are
intended for use during payload antenna testing while on the launch pad, not for use during flight.
(top of page 37 of http://www.spacex.com/sites/spacex/files/falcon_9_users_guide_rev_2.0.pdf)
Title: Re: Fairing reuse
Post by: cscott on 03/31/2017 03:27 PM
Thinking about faring reuse raises some interesting questions.

Historically there seems to have been a fair bit of customizing on the fairing for each payload. Custom sized (and shaped) doors and access panels.

SpaceX doesn't do customized fairings (yet). "Historically" applies to other LSP's.
In 2015 at least they offered a little bit of customization.   The user guide says:
Quote
The fairing can accommodate up to two access doors in the cylindrical portion as a standard service. The
standard payload fairing door is elliptical, with a maximum size of 450 x 550 mm (17.7 x 21.7 in.).

Through-fairing RF antenna (re-radiation) systems are available as a nonstandard service; they are
intended for use during payload antenna testing while on the launch pad, not for use during flight.
(top of page 37 of http://www.spacex.com/sites/spacex/files/falcon_9_users_guide_rev_2.0.pdf)
Padrat is a SpaceX employee. His post is definitive.
Title: Re: Fairing reuse
Post by: CharlieWildman on 03/31/2017 03:36 PM
I fly paraplanes and paragliders. The control mechanism setup is be very easy and cheap for a steerable parachute (parafoil).

Parafoils use wing warping for heading changes and throttle or thermals for altitude changes. One servo with a capstan holding both control wires will provide perfect directional control. Pulling on one set of risers while  releasing the other set is how control is maintained. Pitch is mostly irrelevant with a parafoil, and altitude can be bled off by circling as needed. 

They can circle down and fly the shell halves back towards shore remotely for helicopter pickup just off the coast or airbag landing in the water (Elon's "bouncy house").  Or just land them right in the brush at LZ-1. They are going to want a fairly low glide ratio (like 2:1 or 3:1) because the huge surface area of the aeroshell half underneath that is also catching the wind.

I wonder how long it took for the fairing halves to reach the water.  If under a parafoil obliviously significantly longer than the booster.  Maybe there would be enough time to safe the booster, attach Rumba, scooch the booster to one end of the ASDS then inflate a bouncy house and land the fairings. Just a crazy idea.
Title: Re: Fairing reuse
Post by: JasonAW3 on 03/31/2017 03:49 PM
Is anyone else surprised the fairing sank? They were close enough to photograph it, they didn't have the gear to retrieve it? Also, isn't it filled with air pockets from the construction method? A sizable piece floated to the Bahamas not so long ago.

Matthew

Even if the didn't, a couple of float bags with CO2 inflation cartridges would't be too hard to rig.  Heck, they could even rig the inflaters to go off when the are immersed in seawater, like the Navy has for their lifeboats.
Title: Re: Fairing reuse
Post by: cscott on 03/31/2017 04:19 PM
Is anyone else surprised the fairing sank? They were close enough to photograph it, they didn't have the gear to retrieve it? Also, isn't it filled with air pockets from the construction method? A sizable piece floated to the Bahamas not so long ago.

Matthew

Even if the didn't, a couple of float bags with CO2 inflation cartridges would't be too hard to rig.  Heck, they could even rig the inflaters to go off when the are immersed in seawater, like the Navy has for their lifeboats.
Float bags don't help you find small pieces in the middle of the Atlantic at night.
Title: Re: Fairing reuse
Post by: Phil Stooke on 03/31/2017 04:23 PM
No... but if it's in one piece it will be there in the morning.
Title: Re: Fairing reuse
Post by: cscott on 03/31/2017 04:29 PM
No... but if it's in one piece it will be there in the morning.
I'm not ruling out seeing pieces return on the deck of Go Searcher.  I think that's consistent with Elon's clarification.

I think you're underestimating the difficulty of finding even a mostly intact fairing half in the middle of the ocean if telemetry ceases on impact or after battery exhaustion.
Title: Re: Fairing reuse
Post by: Paul_G on 03/31/2017 05:09 PM
We don't know exactly what the photo was: it's possible it was a "chutes out but not yet in contact with ocean" shot from a considerable distance, like we get of dragon recovery.

Didn't Martin Halliwell joke that it was the wrong half - which I take to mean the half with the SES log on. Presumably the photo must have been taken relatively close for that to be visible?

Paul
Title: Re: Fairing reuse
Post by: mme on 03/31/2017 05:20 PM
Is anyone else surprised the fairing sank? They were close enough to photograph it, they didn't have the gear to retrieve it? Also, isn't it filled with air pockets from the construction method? A sizable piece floated to the Bahamas not so long ago.

Matthew

Even if the didn't, a couple of float bags with CO2 inflation cartridges would't be too hard to rig.  Heck, they could even rig the inflaters to go off when the are immersed in seawater, like the Navy has for their lifeboats.
Gwynne Shotwell has stated that they want to keep them out of the water.  So I believe the next steps will be working toward landing them on something.
Title: Re: Fairing reuse
Post by: cscott on 03/31/2017 05:24 PM
We don't know exactly what the photo was: it's possible it was a "chutes out but not yet in contact with ocean" shot from a considerable distance, like we get of dragon recovery.

Didn't Martin Halliwell joke that it was the wrong half - which I take to mean the half with the SES log on. Presumably the photo must have been taken relatively close for that to be visible?

Paul
Maybe?  Hard to say.  Compare this photo of Dragon, perhaps taken at roughly similar stand-off distance and light. (However, note that dragon landing is at sun*rise*, to give the recovery team maximum working time, while the fairing reentered at sun*set*.)

Now imagine that the fairing was *catching* the light, instead of being silhouetted.  You'd have to make some assumptions about the angle the fairing is held under the parafoil.  I could argue either way.  If things are just right, you might be able to just make out the flag (or, more likely, lack of SES logo).  Or if the conditions are wrong (fairing close to horizontal, fairing in silhouette) I could see how it would be impossible to tell at that distance.

Maybe this actually came up in earlier banter, so the SES CEO knew already that only one half would be recovered, and that it wouldn't be the "right" one, so it didn't have to be visible in the photo either way.
Title: Re: Fairing reuse
Post by: CraigLieb on 03/31/2017 06:06 PM
We are beginning to see the designs of Elon, the evil genius...  (pinkie firmly planted in corner of mouth)

The fairing will deploy cold-gas thrusters and small pop-out grid fins to stabilize into a flyable aeroshell, navigating to a selected capture zone. At which point, the very large airship will open up it's large under slung cargo hold and the fairings will fly in and be caught in nets. The airship will then make its way to Elon's secret volcano lair ... which opens up it's hidden landing pad area, etc. Submarines or fast boats will return the shells to shore for additional processing.

 8)

I was really close here...   
    thrusters (check - sort of)
    flyable aeroshell  (sort of again, check)
    airship = really large bouncy castle  (check)

volcano lair ... welllll, we don't know the whole plan yet, really so I still have a shot.

 8)

Edit/Lar: Followups probably at some point belong in the party thread. That's where I replied anyway... :)
Title: Re: Fairing reuse
Post by: Stan-1967 on 03/31/2017 06:29 PM
If the parafoil can maneuver for a precision landing, I think SpaceX should be able to recover both halves with a single ship or barge.  I envision deploying booms off the starboard & port sides, and each half has it's own landing space.  See the attached image & replace a barge or ship instead of the proud guy who needs floaties in the swimming pool.

The ship or barge in the middle would have a crane or hoist to move the fairing onto the vessel.  It may also be an open question if this method can work like the rocket DPL concept where the barge is at a predetermined GPS coordinate.  This method may require the ship to chase the fairings within the landing ellipse & the fairings may need a way to identify the landing target & self guide.   Not enough information to know what it will be at this point.
Title: Re: Fairing reuse
Post by: rsdavis9 on 03/31/2017 07:26 PM
If the parafoil can maneuver for a precision landing, I think SpaceX should be able to recover both halves with a single ship or barge.  I envision deploying booms off the starboard & port sides, and each half has it's own landing space.  See the attached image & replace a barge or ship instead of the proud guy who needs floaties in the swimming pool.

The ship or barge in the middle would have a crane or hoist to move the fairing onto the vessel.  It may also be an open question if this method can work like the rocket DPL concept where the barge is at a predetermined GPS coordinate.  This method may require the ship to chase the fairings within the landing ellipse & the fairings may need a way to identify the landing target & self guide.   Not enough information to know what it will be at this point.

Or the BO method. Moving recovery vessel and bring PLF down on a moving vessel. Vessel could be lots of things...
Title: Re: Fairing reuse
Post by: john smith 19 on 03/31/2017 07:47 PM
There isn't really much customization done to the fairings. We're working towards keeping them very generic, obviously an advantage when you want to eventually reuse them. The goal, at least for the commercial customers, is to get to a basic universal design where the only differences are the logo and antenna setup. The most customization gets done to the payload adapter, of course. But yet, even those are surprisingly the same few basic setups (mostly)
This is one of those odd little quirks that only seems important to space geeks but is actually turning out to be a key to making the reuse of this structure affordable.

I note you specify commercial customers. That suggests govt payloads under the EELV contracts may be more customized. Will that rule out reuse entirely?
Is anyone else surprised the fairing sank? They were close enough to photograph it, they didn't have the gear to retrieve it? Also, isn't it filled with air pockets from the construction method? A sizable piece floated to the Bahamas not so long ago.

Matthew

Even if the didn't, a couple of float bags with CO2 inflation cartridges would't be too hard to rig.  Heck, they could even rig the inflaters to go off when the are immersed in seawater, like the Navy has for their lifeboats.
Float bags don't help you find small pieces in the middle of the Atlantic at night.
The obvious answer to which is of course don't launch at night.  :)

However failing that this has been a problem before. The usual answer are some high intensity low frequency strobe beacons. I'm guessing you could put them in some little fairings on the outside so as the halves floated down their flickering would be seen for miles, barring heavy fog.
Title: Re: Fairing reuse
Post by: CraigLieb on 03/31/2017 07:48 PM
anyone notice the image before fairing release? In hosted webcast? Mission time 3:43
Title: Re: Fairing reuse
Post by: Bargemanos on 03/31/2017 08:37 PM
anyone notice the image before fairing release? In hosted webcast? Mission time 3:43


Just compared with the Echostar 23 launch but didn't find any notable difference.
Title: Re: Fairing reuse
Post by: cscott on 03/31/2017 08:47 PM
We could be looking at the wrong side of the fairing in those pictures.
Title: Re: Fairing reuse
Post by: DAZ on 03/31/2017 09:37 PM
I guess the fairing landed, but was not recovered. (sunk before they could get to it?)
https://twitter.com/SpaceBrendan/status/847599001746644996
Quote
Brendan Byrne @SpaceBrendan
Musk: Correction, not recovered, but it was directed to a landing area. Will have "bouncy" castle soon.

Aha! So it looks like my guess that they will try to land it on an inflated surface was correct.  8)

Your guess and others.
Title: Re: Fairing reuse
Post by: gosink on 04/01/2017 05:38 PM
The following links might be of general interest with respect to the topic of steerable automated parachutes & parafoils: 

https://www.youtube.com/watch?v=iFNFUqIRbkc
https://www.youtube.com/watch?v=yQlj5-aWdSk
Title: Re: Fairing reuse
Post by: savuporo on 04/01/2017 06:48 PM
The following links might be of general interest with respect to the topic of steerable automated parachutes & parafoils:..

https://www.youtube.com/results?search_query=joint+precision+airdrop+system
Title: Re: Fairing reuse
Post by: NX-0 on 04/01/2017 09:23 PM
I guess the fairing landed, but was not recovered. (sunk before they could get to it?)
https://twitter.com/SpaceBrendan/status/847599001746644996
Quote
Brendan Byrne @SpaceBrendan
Musk: Correction, not recovered, but it was directed to a landing area. Will have "bouncy" castle soon.

Aha! So it looks like my guess that they will try to land it on an inflated surface was correct.  8)

I was told by one of the fairing recovery engineers this morning the fairing was recovered.
"It was recovered and hoisted into the boat."
Confirmed they only experiment with one piece of the fairing at a time.
Problem, I was told, is that some of the 'chute lines used for steering broke.

This is the first time I have had anything close to first-hand information like this.
Title: Re: Fairing reuse
Post by: cppetrie on 04/01/2017 09:26 PM
I guess the fairing landed, but was not recovered. (sunk before they could get to it?)
https://twitter.com/SpaceBrendan/status/847599001746644996
Quote
Brendan Byrne @SpaceBrendan
Musk: Correction, not recovered, but it was directed to a landing area. Will have "bouncy" castle soon.

Aha! So it looks like my guess that they will try to land it on an inflated surface was correct.  8)

I was told by one of the fairing recovery engineers this morning the fairing was recovered.
"It was recovered and hoisted into the boat."
Confirmed they only experiment with one piece of the fairing at a time.
Problem, I was told, is that some of the 'chute lines used for steering broke.

This is the first time I have had anything close to first-hand information like this.
So Elon probably meant it wasn't recovered in the "we can reuse it" sense but it was recovered in the "we found it and retrieved it" sense
Title: Re: Fairing reuse
Post by: FutureSpaceTourist on 04/03/2017 07:22 AM
Gwynne Shotwell is speaking at the 33rd Space Symposium on Wednesday. Hopefully there'll be some more info then and at least a photo? Just time to get everything back to port and do some editing prior to the presentation.
Title: Re: Fairing reuse
Post by: FutureSpaceTourist on 04/03/2017 11:28 AM
Possible return of recovered fairing to port? (image re-attached for convenience)

Quote
Scott M‏ @Restrantek 13m13 minutes ago

The Go Searcher is back in port. #SpaceX is there a fairing or portion of under the tarps? Will be docked at SpaceX Barge Dock

https://twitter.com/Restrantek/status/848855345556533248 (https://twitter.com/Restrantek/status/848855345556533248)
Title: Re: Fairing reuse
Post by: Semmel on 04/03/2017 12:51 PM
removed my comment as images show, it was not a April fools joke. Thanks for the info NX-0!
Title: Re: Fairing reuse
Post by: Darga on 04/03/2017 01:36 PM
Loads of pics from Reddit user aftersteveo https://imgur.com/gallery/qa2rB
Title: Re: Fairing reuse
Post by: Wolfram66 on 04/03/2017 01:47 PM
The need to equip or obtain a boat with an A-Frame hoist on the rear like they use to launch ROV's or deep sea research subs. That will make fairing retrieval easier
Title: Re: Fairing reuse
Post by: JamesH65 on 04/03/2017 02:19 PM
The need to equip or obtain a boat with an A-Frame hoist on the rear like they use to launch ROV's or deep sea research subs. That will make fairing retrieval easier

Only if they need to crane out of the water, and they have said they don't want to get it wet.
Title: Re: Fairing reuse
Post by: Wolfram66 on 04/03/2017 02:42 PM
The need to equip or obtain a boat with an A-Frame hoist on the rear like they use to launch ROV's or deep sea research subs. That will make fairing retrieval easier

Only if they need to crane out of the water, and they have said they don't want to get it wet.

Or to get it off the Bouncy Castle
Title: Re: Fairing reuse
Post by: whitelancer64 on 04/03/2017 02:51 PM
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.
Title: Re: Fairing reuse
Post by: JamesH65 on 04/03/2017 02:55 PM
The need to equip or obtain a boat with an A-Frame hoist on the rear like they use to launch ROV's or deep sea research subs. That will make fairing retrieval easier

Only if they need to crane out of the water, and they have said they don't want to get it wet.

Or to get it off the Bouncy Castle

Needs more than an a-frame on the back of a support ship for that.
Title: Re: Fairing reuse
Post by: Lar on 04/03/2017 03:01 PM
The need to equip or obtain a boat with an A-Frame hoist on the rear like they use to launch ROV's or deep sea research subs. That will make fairing retrieval easier

Only if they need to crane out of the water, and they have said they don't want to get it wet.

Or to get it off the Bouncy Castle

Needs more than an a-frame on the back of a support ship for that.

Do that in port. Just cinch it down with cross straps and leave the castle inflated (at least partly) to cushion it where it rests for transport.
Title: Re: Fairing reuse
Post by: mattstep on 04/03/2017 03:03 PM
The need to equip or obtain a boat with an A-Frame hoist on the rear like they use to launch ROV's or deep sea research subs. That will make fairing retrieval easier

Only if they need to crane out of the water, and they have said they don't want to get it wet.

Or to get it off the Bouncy Castle

Do that in port. Just cinch it down with cross straps and leave the castle inflated (at least partly to cushion it where it rests for transport.

Needs more than an a-frame on the back of a support ship for that.

That's assuming the bouncy castle is on the back of a ship. It could be floating on its own and just anchored or tethered to the support ship or ASDS.
Title: Re: Fairing reuse
Post by: AAPSkylab on 04/03/2017 04:17 PM
How about towing a bouncy castle into the wind.

Fairing under parafoil (or stearable parachute) turns into the wind on landing leg.

Similar to landing on aircraft carrier.

Minimize relative horizontal motion at touchdown.
Title: Re: Fairing reuse
Post by: Kaputnik on 04/03/2017 04:32 PM
How about towing a bouncy castle into the wind.

Fairing under parafoil (or stearable parachute) turns into the wind on landing leg.

Similar to landing on aircraft carrier.

Minimize relative horizontal motion at touchdown.

I've done a bit of paragliding in the past, and a steerable foil has fairly limited control available. Obviously as a glider you cannot increase speed or altitude using power, so you need to stay on the 'high side' all the way in.
I was taught to land by making a gentle curving approach towards my LZ. If I felt I was too high, widen the curve to increase the distance travelled. If I thought I was too low, tighten the curve.

I'm not going to say it's impossible to do this manoeuvre onto a moving target, but it kind of makes my head hurt thinking about how you would fly that. But of course the fairings won't be flown by a mere human.
Title: Re: Fairing reuse
Post by: Barrie on 04/03/2017 04:38 PM
Maybe it will be less like a bouncy castle and more like a big lilo, turned up at the sides and at one end.  Like a stylized catcher's mitt.  The fairing approaches from the more open end.
Title: Re: Fairing reuse
Post by: rsdavis9 on 04/03/2017 05:01 PM
Fast catamarans to do the final catch.
What can a cat do on the water and what will a paragliding PLF be doing?
35 knots?
Title: Re: Fairing reuse
Post by: TrevorMonty on 04/03/2017 06:08 PM
Why not bouncing castle on boat in picture, looks big enough. Will need two boats.  At $3m a half fairing they can afford to charter another boat for a few days.
Title: Re: Fairing reuse
Post by: savuporo on 04/03/2017 08:40 PM
... it kind of makes my head hurt thinking about how you would fly that. ..
Eh .. i've done a few swoop landing competitions. Not that i  won a lot, but it's not that hard. A few sky gods i know have done landings in a back of a truck.
Plus, look up thread and read up on what JPADs are doing today fully autonomously.
Title: Re: Fairing reuse
Post by: RDoc 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.
Title: Re: Fairing reuse
Post by: savuporo 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.
Title: Re: Fairing reuse
Post by: iamlucky13 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.
Title: Re: Fairing reuse
Post by: deruch 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. 
Title: Re: Fairing reuse
Post by: cppetrie 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.
Title: Re: Fairing reuse
Post by: meekGee 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?
Title: Re: Fairing reuse
Post by: cppetrie 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.
Title: Re: Fairing reuse
Post by: JamesH65 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.
Title: Re: Fairing reuse
Post by: rsdavis9 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.
Title: Re: Fairing reuse
Post by: sevenperforce 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.
Title: Re: Fairing reuse
Post by: Robotbeat 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. 😂

We're well past the laughing stage...

Quote
First they ignore you, then they laugh at you, then they fight you, then you win*.
-- Mahatma Gandhi

https://www.brainyquote.com/quotes/quotes/m/mahatmagan103630.html

* We are here.
Yeah, but "bouncy castle" is funny! :)
Title: Re: Fairing reuse
Post by: Kaputnik 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.
Title: Re: Fairing reuse
Post by: speedevil 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.
(https://ichef-1.bbci.co.uk/news/624/cpsprodpb/5172/production/_86905802_rocketttrescoisland.jpg)
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 :)
Title: Re: Fairing reuse
Post by: JamesH65 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.





Title: Re: Fairing reuse
Post by: rsdavis9 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. :)
Title: Re: Fairing reuse
Post by: Basto 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.
Title: Re: Fairing reuse
Post by: ellindsey 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.
Title: Re: Fairing reuse
Post by: JamesH65 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.
Title: Re: Fairing reuse
Post by: Basto 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!
Title: Re: Fairing reuse
Post by: speedevil 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.
Title: Re: Fairing reuse
Post by: Alastor on 04/04/2017 03:54 PM
Any form of moving target would either require precise pre-planning, which doesn't work if you don't compensate the effects of winds, or require real time communication between the target and the fairing.

Comms means more weight, and the risks of communication failiures.
They already avoid doing that for the first stage and use a fixed rendez-vous point instead.

My bet is they will use the same strategy for the fairing, as it removes a lot of requirements and additional failiure modes:  fixed predetermined rendez-vous point.
Title: Re: Fairing reuse
Post by: iamlucky13 on 04/04/2017 05:51 PM
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.

True, but the damage looks pretty extensive to me. Depending which end we're looking at (I think aft), either nose or the boat tail seems to be largely broken off. As discussed upthread, the fairing is a much more substantial structure than most people realize. It seems likely to me it sustained non-trivial damage on entry and/or splashdown, and handling it aboard the vessel no doubt made it worse.

I doubt we'll get detailed comments from SpaceX on their findings, but this should be quite helpful to them in understanding what it takes for a fairing to survive.

Note that there have been some references in the past to "Fairing 2.0." Some changes are already in the works, so there could be a major improvement in re-entry performance pending.

By the way, Musk mentioned in the post-launch press conference that the fairing has thrusters to stabilize it during entry. I don't think that had been confirmed before.
Title: Re: Fairing reuse
Post by: OnWithTheShow on 04/05/2017 01:27 AM
Why not put the "bouncy castle" in the fairing?
Title: Re: Fairing reuse
Post by: JamesH65 on 04/05/2017 08:45 AM
Any form of moving target would either require precise pre-planning, which doesn't work if you don't compensate the effects of winds, or require real time communication between the target and the fairing.

Comms means more weight, and the risks of communication failiures.
They already avoid doing that for the first stage and use a fixed rendez-vous point instead.

My bet is they will use the same strategy for the fairing, as it removes a lot of requirements and additional failiure modes:  fixed predetermined rendez-vous point.

I still cannot see how, without knowing the instantaneous wind conditions at the LZ, how they expect to accurately land under parachute. Remember, parachutes are much more affected by the wind, and have more time to be affected than the 1st stage. You always want to land in to the wind to reduces ground speed, so you NEED to know the wind direction, which could easily have changed between launch and landing.

If you are preprogramming the wind direction, what is the last point at which you can do so? Days in advance? Just prior to launch? There needs to be some mechanism to tell the fairing the wind direction, even before launch.
Title: Re: Fairing reuse
Post by: JJB on 04/05/2017 09:45 AM
https://vimeo.com/133990314 (https://vimeo.com/133990314)
Landing on the "Bouncy Castle" Is not that hard, I do this without instruments,with instruments and a 360 overhead even a computer can do this.
Title: Re: Fairing reuse
Post by: JamesH65 on 04/05/2017 09:55 AM
https://vimeo.com/133990314 (https://vimeo.com/133990314)
Landing on the "Bouncy Castle" Is not that hard, I do this without instruments,with instruments and a 360 overhead even a computer can do this.

Can you do it so accurately when flying downwind? You clearly turned in to the wind for the final landing approach.
Title: Re: Fairing reuse
Post by: JJB on 04/05/2017 10:03 AM
https://vimeo.com/133990314 (https://vimeo.com/133990314)
Landing on the "Bouncy Castle" Is not that hard, I do this without instruments,with instruments and a 360 overhead even a computer can do this.

Can you do it so accurately when flying downwind? You clearly turned in to the wind for the final landing approach.
Thats why you do a 360 turn overhead the target, gps derived wind speed and direction.
Title: Re: Fairing reuse
Post by: Kaputnik on 04/05/2017 11:05 AM
Why not put the "bouncy castle" in the fairing?

A big enough inflatable to keep the fairing completely out of the water is probably far too big/heavy to carry on the fairing.
Title: Re: Fairing reuse
Post by: JamesH65 on 04/05/2017 11:27 AM
https://vimeo.com/133990314 (https://vimeo.com/133990314)
Landing on the "Bouncy Castle" Is not that hard, I do this without instruments,with instruments and a 360 overhead even a computer can do this.

Can you do it so accurately when flying downwind? You clearly turned in to the wind for the final landing approach.
Thats why you do a 360 turn overhead the target, gps derived wind speed and direction.

Ah ha, thanks for the explanation. That's the missing information.  Question is now -does a falling fairing have enough time to do a 360 loop round the target to assess wind speed/direction. Which is a question we don;t have an answer for without knowing the glide ratio.
Title: Re: Fairing reuse
Post by: speedevil on 04/05/2017 12:01 PM
Ah ha, thanks for the explanation. That's the missing information.  Question is now -does a falling fairing have enough time to do a 360 loop round the target to assess wind speed/direction. Which is a question we don;t have an answer for without knowing the glide ratio.

It doesn't need it - there are various ways of getting live wind data from the landing platform, up to and including a dozen $1K drones standing off 500m and reporting live windspeeds and gusts 10s before they hit.
Title: Re: Fairing reuse
Post by: cppetrie on 04/05/2017 01:49 PM
Ah ha, thanks for the explanation. That's the missing information.  Question is now -does a falling fairing have enough time to do a 360 loop round the target to assess wind speed/direction. Which is a question we don;t have an answer for without knowing the glide ratio.

It doesn't need it - there are various ways of getting live wind data from the landing platform, up to and including a dozen $1K drones standing off 500m and reporting live windspeeds and gusts 10s before they hit.
It also has onboard thrusters that could assist with positioning/trajectory.
Title: Re: Fairing reuse
Post by: kaiser on 04/05/2017 03:31 PM
Ah ha, thanks for the explanation. That's the missing information.  Question is now -does a falling fairing have enough time to do a 360 loop round the target to assess wind speed/direction. Which is a question we don;t have an answer for without knowing the glide ratio.

It doesn't need it - there are various ways of getting live wind data from the landing platform, up to and including a dozen $1K drones standing off 500m and reporting live windspeeds and gusts 10s before they hit.

If you had a good multi-hypothesis navigation filter, you might be able to fairly accurately tell the wind speed just during normal descent based upon the transfer function between your control inputs and positional change during the descent.
Title: Re: Fairing reuse
Post by: Alastor on 04/05/2017 03:33 PM
It also has onboard thrusters that could assist with positioning/trajectory.