Author Topic: Fairing reuse  (Read 510916 times)

Offline obi-wan

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Re: Fairing reuse
« Reply #1620 on: 05/18/2018 09:31 PM »
I'm skeptical about the merit of fairing reuse. It is something every other launchers can implement at any time. The development cost is not prohibitive, there is nothing that would prevent its development. But nobody has try in space flight history.
 I guess it's just a marketing gimmick by elon musk. The question would be how much added cost they can tolerate rather than how much it can save.

Wrong in a bunch of ways. 

1.  a)SpaceX fairings are significantly different from other manufacturers'.  Because of the way that SpaceX has chosen to horizontally integrate the encapsulated payloads with their rockets, their fairings are built to support much higher forces than is normal (i.e. weight of the payload is, at times, supported by the fairing).  This means that they are much more rigid (as well as heavier).  And as a result, they may have a distinct advantage over other fairings in controllably surviving reentry without as much modification.  To see this difference, watch how wobbly/flappy other fairings are on jettison.
{rest snipped because this is what I'm replying to}

I know this has been discussed before on this site, but no, no, NO!!! The fairing DOES NOT _EVER_ support the payload, on any vehicle, for any reason! Check out the payload user's guides for any launch vehicle, including F9. ALL the loads for the payload are taken through the payload attach fitting (PAF), which is the ring at the top of the upper stage to which the payload attaches (typically with a Marman band or other low-shock separation device). The payload volume is defined as a dynamic envelope which the payload can never exceed under the worst case loading. That's because the payload fairing will never enter that volume under its worst case loading. If the payload fairing ever touches the payload, you have an indeterminate loading condition where the payload is assuming some of the fairing loads, or vice versa. There is no way to predict the loads in that case, so there's no way to qualify the payload or fairing if that happens.

When the F9 is horizontal, the payload is cantilevered from the PAF. The fairing is cantilevered from its mounting fixture around the upper stage. Most launch providers have a very large piece of GSE that will hold the integrated fairing/payload cantilevered from the mounting face for integration to the launch vehicle if they use horizontal integration.

I can't say categorically that SpaceX does not use the fairing as a lifting point for payload integration, although that would require either that every fairing is designed for the mass and inertia of its specific payload, or that every fairing is designed to take the loads of the heaviest payload F9 is capable of flying, either of which would be surprising as compared to just making some GSE to take the loads. But I will say categorically that the payload never, ever touches the inside of the fairing, as payload designers would find it impossible to definitively calculate those loads and verify against the (nondeterministic) models.

Offline deruch

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Re: Fairing reuse
« Reply #1621 on: 05/19/2018 09:29 AM »
I'm skeptical about the merit of fairing reuse. It is something every other launchers can implement at any time. The development cost is not prohibitive, there is nothing that would prevent its development. But nobody has try in space flight history.
 I guess it's just a marketing gimmick by elon musk. The question would be how much added cost they can tolerate rather than how much it can save.

Wrong in a bunch of ways. 

1.  a)SpaceX fairings are significantly different from other manufacturers'.  Because of the way that SpaceX has chosen to horizontally integrate the encapsulated payloads with their rockets, their fairings are built to support much higher forces than is normal (i.e. weight of the payload is, at times, supported by the fairing).  This means that they are much more rigid (as well as heavier).  And as a result, they may have a distinct advantage over other fairings in controllably surviving reentry without as much modification.  To see this difference, watch how wobbly/flappy other fairings are on jettison.
{rest snipped because this is what I'm replying to}
I can't say categorically that SpaceX does not use the fairing as a lifting point for payload integration, although that would require either that every fairing is designed for the mass and inertia of its specific payload, or that every fairing is designed to take the loads of the heaviest payload F9 is capable of flying, either of which would be surprising as compared to just making some GSE to take the loads. But I will say categorically that the payload never, ever touches the inside of the fairing, as payload designers would find it impossible to definitively calculate those loads and verify against the (nondeterministic) models.

This is what I was talking about.  Not that the payload ever touches the fairing but that loads are carried through it when, post encapsulation, they break it over from vertical to horizontal and then integrate it with the rocket.  Once it is integrated, the loads are either entirely or almost entirely carried by the rocket.  But SpaceX doesn't (or at least didn't in the past) use a specialized bit of GSE to keep all the forces running through the PAF.  They used the HIF cranes with lift points on the fairing which means the load path partially runs through the fairing.
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Online Comga

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Re: Fairing reuse
« Reply #1622 on: 05/19/2018 08:25 PM »
I'm skeptical about the merit of fairing reuse. It is something every other launchers can implement at any time. The development cost is not prohibitive, there is nothing that would prevent its development. But nobody has try in space flight history.
 I guess it's just a marketing gimmick by elon musk. The question would be how much added cost they can tolerate rather than how much it can save.

Wrong in a bunch of ways. 

1.  a)SpaceX fairings are significantly different from other manufacturers'.  Because of the way that SpaceX has chosen to horizontally integrate the encapsulated payloads with their rockets, their fairings are built to support much higher forces than is normal (i.e. weight of the payload is, at times, supported by the fairing).  This means that they are much more rigid (as well as heavier).  And as a result, they may have a distinct advantage over other fairings in controllably surviving reentry without as much modification.  To see this difference, watch how wobbly/flappy other fairings are on jettison.
{rest snipped because this is what I'm replying to}
I can't say categorically that SpaceX does not use the fairing as a lifting point for payload integration, although that would require either that every fairing is designed for the mass and inertia of its specific payload, or that every fairing is designed to take the loads of the heaviest payload F9 is capable of flying, either of which would be surprising as compared to just making some GSE to take the loads. But I will say categorically that the payload never, ever touches the inside of the fairing, as payload designers would find it impossible to definitively calculate those loads and verify against the (nondeterministic) models.

This is what I was talking about.  Not that the payload ever touches the fairing but that loads are carried through it when, post encapsulation, they break it over from vertical to horizontal and then integrate it with the rocket.  Once it is integrated, the loads are either entirely or almost entirely carried by the rocket.  But SpaceX doesn't (or at least didn't in the past) use a specialized bit of GSE to keep all the forces running through the PAF.  They used the HIF cranes with lift points on the fairing which means the load path partially runs through the fairing.
Please read the previous post with more care.
Your statements are false.
« Last Edit: 05/19/2018 08:26 PM by Comga »
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline deruch

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Re: Fairing reuse
« Reply #1623 on: 05/20/2018 05:34 AM »
This is what I was talking about.  Not that the payload ever touches the fairing but that loads are carried through it when, post encapsulation, they break it over from vertical to horizontal and then integrate it with the rocket.  Once it is integrated, the loads are either entirely or almost entirely carried by the rocket.  But SpaceX doesn't (or at least didn't in the past) use a specialized bit of GSE to keep all the forces running through the PAF.  They used the HIF cranes with lift points on the fairing which means the load path partially runs through the fairing.
Please read the previous post with more care.
Your statements are false.

Here's the lift and breakover of the Jason-3 mission.

https://www.flickr.com/photos/nasakennedy/23776528834/
Quote
KSC-20160111-PH_TNN0001-0006

In the SpaceX Payload Processing Facility at Vandenberg Air Force Base in California, the Jason-3 satellite is fully encapsulated in its payload fairing. With this step complete, Jason-3 will be mated to a SpaceX Falcon 9 rocket at Vandenberg's Space Launch Complex 4. Built by Thales Alenia of France, Jason-3 will measure the topography of the ocean surface for a four-agency international partnership consisting of NOAA, NASA, Centre National d’Etudes Spatiales, France’s space agency, and the European Organization for the Exploitation of Meteorological Satellites.

https://www.flickr.com/photos/nasakennedy/24322264661/
Quote
KSC-20160111-PH_TNN0001-0007

In the SpaceX Payload Processing Facility at Vandenberg Air Force Base in California, the payload fairing containing the Jason-3 satellite has been rotated to horizontal in preparation for mating to a SpaceX Falcon 9 rocket at Vandenberg's Space Launch Complex 4. Built by Thales Alenia of France, Jason-3 will measure the topography of the ocean surface for a four-agency international partnership consisting of NOAA, NASA, Centre National d’Etudes Spatiales, France’s space agency, and the European Organization for the Exploitation of Meteorological Satellites.
Photo credits: NASA/Thiep Nguyen and Christopher Wiant

Maybe things have changed or, for heavier payloads, they do things differently but we haven't seen any evidence of this [excluding Dragon which is treated differently and does have a unique breakover fixture].  When coupled with the manner that they support the fairings during roll-out and while the rocket is horizontal on the pad prior to being erected, I think the point about load paths still stands.  Of course, if you have any evidence of relevant changes (even if it's just passed along info from those who have first hand knowledge) I'd be very interested to see/hear it.
« Last Edit: 05/20/2018 05:53 AM by deruch »
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Offline OxCartMark

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Re: Fairing reuse
« Reply #1624 on: 05/24/2018 03:17 AM »
So I saw that the fairings went up and I saw them fall back down and I see that Mr. Steven is in port.  Those are the basic facts.  Can anyone fill in the details?

Offline FutureSpaceTourist

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Re: Fairing reuse
« Reply #1625 on: 05/24/2018 07:00 AM »
Quote
Mr Steven returned to port around 7pm PST May 23 with both Iridium-6/GRACE-FO fairing halves aboard, by all appearances intact! Seawater immersion means no reuse, but they may find use as drop test articles to refine accuracy :D @NASAJPL @IridiumBoss @nextspaceflight @Teslarati

https://twitter.com/13ericralph31/status/999541304437571590

Quote
Given the fact that they seem to have figured out how to recovery fairings intact from the ocean surface, it's truly just a matter of time before @SpaceX engineers & techs refine the accuracy enough for Mr Steven to catch them out of the air. Live coverage included, perhaps...

https://twitter.com/13ericralph31/status/999541309713956864

Quote
Lastly, these incredible photos were taken by @chuckbennett (Instagram username is the same) a skilled photog & editor (you may recognize him from past work w/ The Daily Breeze). Meanwhile, @w00ki33 is heading down to capture the fairings from the docks, so very neo-noir 😁 🤞

https://twitter.com/13ericralph31/status/999541310695469056

Offline john smith 19

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Re: Fairing reuse
« Reply #1626 on: 05/24/2018 07:48 AM »
Quote
Mr Steven returned to port around 7pm PST May 23 with both Iridium-6/GRACE-FO fairing halves aboard, by all appearances intact! Seawater immersion means no reuse, but they may find use as drop test articles to refine accuracy :D @NASAJPL @IridiumBoss @nextspaceflight @Teslarati

https://twitter.com/13ericralph31/status/999541304437571590

Quote
Given the fact that they seem to have figured out how to recovery fairings intact from the ocean surface, it's truly just a matter of time before @SpaceX engineers & techs refine the accuracy enough for Mr Steven to catch them out of the air. Live coverage included, perhaps...

https://twitter.com/13ericralph31/status/999541309713956864

Quote
Lastly, these incredible photos were taken by @chuckbennett (Instagram username is the same) a skilled photog & editor (you may recognize him from past work w/ The Daily Breeze). Meanwhile, @w00ki33 is heading down to capture the fairings from the docks, so very neo-noir 😁 🤞
It's pretty clear that SX have made a lot of progress on fairing recovery. Those halves look in pretty good shape compared to the large chunks the last one I saw was in.  Obviously it's impossible to say what damage exposure to seawater has done to them so I guess they'll be off to the testing shop to find out.

I'd expect fairing recovery (at least) to be a routine procedure by the end of the year.  We might even see the first fairing reuse by then, depending on wheather post recovery testing shows up any issues.

While I think fairings have been recovered before (some of the early Ariane 5 SRB had recovery parachutes under the nose for inspection) I'm not sure how much analysis was done on them before SX, beyond a quick visual check along the lines of "Looks good. No obvious damage. We could probably use it again." Not using explosive bolts probably goes a long way to minimizing damage from the initial separation event.
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Offline JamesH65

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Re: Fairing reuse
« Reply #1627 on: 05/24/2018 11:48 AM »
It does make you wonder that even if the shell cannot be used, how much of the cost is in fittings on it that can be reused. It might even be cost effective to recover and not use the shell, although I think that unlikely.

Offline rsdavis9

Re: Fairing reuse
« Reply #1628 on: 05/24/2018 12:19 PM »
So I assume because we have seen TWO intact fairings for the last couple of launches that they are putting recovery hardware on both halves?
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Offline woods170

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Re: Fairing reuse
« Reply #1629 on: 05/24/2018 12:21 PM »
So I assume because we have seen TWO intact fairings for the last couple of launches that they are putting recovery hardware on both halves?

Not an assumption but fact. Recovery hardware has been present on BOTH fairing halves on at least two recent missions.

Offline edzieba

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Re: Fairing reuse
« Reply #1630 on: 05/24/2018 12:25 PM »
Almost all the cost is going to be in the big composites (two separate CF layups, plus the sandwiching process of bonding an aluminium honeycomb between them). The other non-recovery hardware (i.e. latches, transducers for payload monitoring, valves for groundside HVAC) is comparatively pocket change, and probably costs less than the added recovery hardware like the RCS, GNC, and parachute system.

Offline laszlo

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Re: Fairing reuse
« Reply #1631 on: 05/24/2018 12:36 PM »
...Obviously it's impossible to say what damage exposure to seawater has done to them so I guess they'll be off to the testing shop to find out...

Preventing seawater damage to composite structures is a well-known technology. I wonder if it'd be cheaper to just build the fairings to tolerate seawater rather than coming up with all the elaborate boat-chasing hardware and procedures. Or are there spaceflight requirements that prevent essentially launching with a boat covering the payload?

Offline deruch

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Re: Fairing reuse
« Reply #1632 on: 05/24/2018 12:39 PM »
Plus the truly major savings is in forgoing the need to build out additional production lines to support raised launch rates.  Those added production lines are real killers in both tooling costs and square footage needs.  And if the increased launch rate isn't enough to make full use of the newly added capacity, then you end up with an inefficient investment as well.
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Offline Cheapchips

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Re: Fairing reuse
« Reply #1633 on: 05/24/2018 12:52 PM »
...Obviously it's impossible to say what damage exposure to seawater has done to them so I guess they'll be off to the testing shop to find out...

Preventing seawater damage to composite structures is a well-known technology. I wonder if it'd be cheaper to just build the fairings to tolerate seawater rather than coming up with all the elaborate boat-chasing hardware and procedures. Or are there spaceflight requirements that prevent essentially launching with a boat covering the payload?

It's presumable not just exposure but physical damage too.  Water's much harder than a net.


Offline john smith 19

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Re: Fairing reuse
« Reply #1634 on: 05/24/2018 04:02 PM »
Plus the truly major savings is in forgoing the need to build out additional production lines to support raised launch rates.  Those added production lines are real killers in both tooling costs and square footage needs.  And if the increased launch rate isn't enough to make full use of the newly added capacity, then you end up with an inefficient investment as well.
True.

The flip side of course is that if BFR is on schedule then there will not be a need to ramp up faring production as BFR will carry those payloads.

In which case this is something of a waste of time.

OTOH if BFR is late this will be a nice cost reduction contingency plan to fall back on (and allow more resources to be diverted to speeding up the BFR roll out).
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Online DistantTemple

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Re: Fairing reuse
« Reply #1635 on: 05/24/2018 04:18 PM »
With nearly 30 launches expected this year (about 20 left) but only 19 next year, there is a short term need now, so it makes even more sense to get reuse working and avoid increasing production facilities.

Assuming Starlink starts launching before BFR is flying... which seems very likely as BFR is at best only expected to do short hops etc during 2019, a lot of fairings, or lots of reuses of fairings, may suddenly be needed. But the timing of that and the overlap with early BFR is an unknown. So ISTM that fairing reuse in place well before that, should facilitate frequent Starlink flights without the cost or possible wait for new fairings, and definitely avoid more production facilities.
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Offline woods170

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Re: Fairing reuse
« Reply #1636 on: 05/24/2018 06:56 PM »
I know this has been discussed before on this site, but no, no, NO!!! The fairing DOES NOT _EVER_ support the payload, on any vehicle, for any reason! Check out the payload user's guides for any launch vehicle, including F9. ALL the loads for the payload are taken through the payload attach fitting (PAF), which is the ring at the top of the upper stage to which the payload attaches (typically with a Marman band or other low-shock separation device). The payload volume is defined as a dynamic envelope which the payload can never exceed under the worst case loading. That's because the payload fairing will never enter that volume under its worst case loading. If the payload fairing ever touches the payload, you have an indeterminate loading condition where the payload is assuming some of the fairing loads, or vice versa. There is no way to predict the loads in that case, so there's no way to qualify the payload or fairing if that happens.

When the F9 is horizontal, the payload is cantilevered from the PAF. The fairing is cantilevered from its mounting fixture around the upper stage. Most launch providers have a very large piece of GSE that will hold the integrated fairing/payload cantilevered from the mounting face for integration to the launch vehicle if they use horizontal integration.

I can't say categorically that SpaceX does not use the fairing as a lifting point for payload integration, although that would require either that every fairing is designed for the mass and inertia of its specific payload, or that every fairing is designed to take the loads of the heaviest payload F9 is capable of flying, either of which would be surprising as compared to just making some GSE to take the loads. But I will say categorically that the payload never, ever touches the inside of the fairing, as payload designers would find it impossible to definitively calculate those loads and verify against the (nondeterministic) models.

You are in fact wrong. The F9 fairing is radically stronger than those of other vehicles, exactly because it supports the entire mass of the payload after integration and breakover of the enclosed payload assembly.

Start here: https://forum.nasaspaceflight.com/index.php?topic=37727.msg1646197#msg1646197
and read the linked posts. They do a great job of explaining.

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« Last Edit: 05/24/2018 06:58 PM by woods170 »

Offline Jim

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Re: Fairing reuse
« Reply #1637 on: 05/24/2018 07:11 PM »

I can't say categorically that SpaceX does not use the fairing as a lifting point for payload integration, although that would require either that every fairing is designed for the mass and inertia of its specific payload, or that every fairing is designed to take the loads of the heaviest payload F9 is capable of flying,

It does. And the fairing lying on its side is taking the load of the payload because the PAF is supported by the fairing and not GSE.

Offline JamesH65

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Re: Fairing reuse
« Reply #1638 on: 05/25/2018 09:16 AM »
Plus the truly major savings is in forgoing the need to build out additional production lines to support raised launch rates.  Those added production lines are real killers in both tooling costs and square footage needs.  And if the increased launch rate isn't enough to make full use of the newly added capacity, then you end up with an inefficient investment as well.
True.

The flip side of course is that if BFR is on schedule then there will not be a need to ramp up faring production as BFR will carry those payloads.

In which case this is something of a waste of time.

OTOH if BFR is late this will be a nice cost reduction contingency plan to fall back on (and allow more resources to be diverted to speeding up the BFR roll out).

There are going to be well over a hundred F9 launches before BFR, probably 200! That, at $6M a pop, is between $600M and $1.2B of fairings thrown away. If it costs $600M (minus refurb costs) to get recovery working, I would be very VERY surprised, so this work is almost certainly worth doing.

Offline edzieba

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Re: Fairing reuse
« Reply #1639 on: 05/25/2018 02:14 PM »
...Obviously it's impossible to say what damage exposure to seawater has done to them so I guess they'll be off to the testing shop to find out...

Preventing seawater damage to composite structures is a well-known technology. I wonder if it'd be cheaper to just build the fairings to tolerate seawater rather than coming up with all the elaborate boat-chasing hardware and procedures. Or are there spaceflight requirements that prevent essentially launching with a boat covering the payload?
The two main techniques for preventing seawater damage to an object, and the only two that are 100% effective, are a) keep the object out of the seawater and b) keep the seawater out of the object.
The fairings need to be porous (vented) to they can be brought from 1ATM or near 0ATM and back without bursting or collapsing, which is at odds with the need to seal them against seawater ingress. Keeping them out of the seawater in the first place is preferable to a complete fairing redesign to avoid internal pockets.

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