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From Reddit Recap of the Elon Musk and Martin Halliwell press conference with lots of new info, March 31, 2017 (presumably not related to April fools day in some time zones?)

Fairing and future second stage recovery

  • Payload fairing LANDED SUCCESSFULLY. Fairing has thruster systems and steerable parachute. Was just shown pic of intact fairing floating in ocean.
  • Upper stage reuse is next.

It says "systems" (plural). Does that mean that each half of the fairing use a thruster post-deployment as part of a recovery effort? If so, how are they used?

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    $\begingroup$ That single comment from the press conference was the only bit of hard information we have on the fairing recovery system. $\endgroup$
    – Hobbes
    Commented Apr 1, 2017 at 7:51
  • $\begingroup$ The two halves are not connected so each one needs a separate system for sure. I did not clearly see the halves after separation on this launch, but I think we could see them in some previous cases when they were already testing the RCS system. CRS-9 (? iirc, will have to check) some ground cam did see the separate halves and something looking like thruster plumes. $\endgroup$
    – jkavalik
    Commented Apr 1, 2017 at 8:42
  • $\begingroup$ @jkavalik I mention "plural" as part of trying to decode this one line of text. I'm thinking that since there are two separate halves, "systems" implies a complete system for each half, and that suggests they are used post-deployment. Here is one place where we can see a fairing separate into two separate pieces: the linked video is already queued up to start playing just before separation $\endgroup$
    – uhoh
    Commented Apr 1, 2017 at 9:00

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Have a look at this video.

You can see one of the fairings stabilizing itself with a thruster around 04:00. Start watching after 02:44 when the 2nd stage engine ignites.

It looks like the bright spot at the top is the 1st stage, using cold gas thrusters, and the bright one at the bottom is the 2nd stage continuing.

The two smaller spots are the fairing halves, and the upper one shows a cold gas thruster plume in the center panel:

enter image description here

These are cropped screenshots from the video:

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  • $\begingroup$ Thanks for this stunning video! In the comments, user James Field posted the following which might explain why we only see cold gas plumes with one of the fairing halves: "SpaceX moved one of their fast response boats (Mr Steven) to the opposite coast for this launch. It has been fitted with a giant circus net to catch one of the fairing halves ... As there's only one boat, I guess they're only trying to recover one fairing half ... they orient the fairing half to enter with the curved broad side hitting the atmosphere first, dissipating as much heat over as large an area as possible." $\endgroup$
    – eerie
    Commented Dec 28, 2017 at 13:35
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In past missions, the second stage camera has caught what look like thrusters firing as the fairing separates. People have speculated that this was early attempts at recovery.

The two halves are not connected after separation so would need their own systems regardless.

The current assumption seems to be that they have cold gas thrusters to orient the fairing for better survivabilty until the parachute can be deployed.

They are light (in terms of size) and fluffy, and have a lot of surface area, so the aero forces on reentry should slow it down quite a bit before parachutes become an option.

Pictures from the recovery ship are starting to appear. An annotated version, of a fairing under a tarp, on the Go Searcher recovery vehicle is interesting to look at.

enter image description here

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  • $\begingroup$ I wonder if they could be called anti-tumble motors. Since the goodies are on the inside and the outside of each half is smooth and convex, the "anti-tumble motors" might be able to establish an outside-down attitude? $\endgroup$
    – uhoh
    Commented Apr 2, 2017 at 14:10
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    $\begingroup$ @uhoh Maybe, maybe not. Just that they recovered one, no sign of thruster or anything else. Also signs it took damage. $\endgroup$
    – geoffc
    Commented Apr 3, 2017 at 15:57
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    $\begingroup$ @eerie that's really incredible footage! Thank you for the link. You could consider leaving a supplemental answer here, possibly adding a screenshot pointing to the fairings' thruster plumes or at least a time code. Also there might be some relevance to the question What is this 'engine plume interaction'?. $\endgroup$
    – uhoh
    Commented Dec 24, 2017 at 3:39
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    $\begingroup$ @uhoh Thanks a lot, I always appreciate ideas on how to improve my posts. It just seems someone else was faster :-) The additional video is incredible, it shows even more detail. Breathtaking! $\endgroup$
    – eerie
    Commented Dec 28, 2017 at 13:29
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    $\begingroup$ @eerie Fairing separation is usually around 110 km altitude, see this question and the great answer there. So all the stuff in the video is really in outer space already (past the Karman line)! $\endgroup$
    – uhoh
    Commented Dec 28, 2017 at 13:40

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