Author Topic: Fairing reuse  (Read 329309 times)

Offline envy887

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Re: Fairing reuse
« Reply #540 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.

Online nacnud

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Re: Fairing reuse
« Reply #541 on: 02/22/2017 06:13 PM »
Any idea of the timing? I.E. Which lands first, the rocket or the fairing?

Offline envy887

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Re: Fairing reuse
« Reply #542 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.

Online nacnud

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Re: Fairing reuse
« Reply #543 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.

Offline cscott

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Re: Fairing reuse
« Reply #544 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?

Offline Lars-J

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Re: Fairing reuse
« Reply #545 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. ;)
« Last Edit: 02/22/2017 08:20 PM by Lars-J »

Offline QuantumG

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Re: Fairing reuse
« Reply #546 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.
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Re: Fairing reuse
« Reply #547 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  :)
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Offline Kaputnik

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Re: Fairing reuse
« Reply #548 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?
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Offline envy887

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Re: Fairing reuse
« Reply #549 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.

Online Stan-1967

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Re: Fairing reuse
« Reply #550 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. 

Offline Lars-J

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Re: Fairing reuse
« Reply #551 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)

Offline woods170

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Re: Fairing reuse
« Reply #552 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.

Offline fast

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Re: Fairing reuse
« Reply #553 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 :)

Offline Hobbes-22

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Re: Fairing reuse
« Reply #554 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?

Offline cscott

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Re: Fairing reuse
« Reply #555 on: 02/23/2017 12:55 PM »
I think woods170 may be referring to loads during horizontal integration.

Offline woods170

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Re: Fairing reuse
« Reply #556 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

And Joek's drawing of it here: 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

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.
« Last Edit: 02/23/2017 01:26 PM by woods170 »

Offline Jim

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Re: Fairing reuse
« Reply #557 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

Offline Jim

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Re: Fairing reuse
« Reply #558 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

Offline mrkmrsk

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Re: Fairing reuse
« Reply #559 on: 02/23/2017 01:22 PM »
And does anyone know the airspeed velocity of an unladen payload fairing?

African, or European?

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