In SpaceX’s most recent Falcon user’s guide, they released more detailed information about the long-awaited extended payload fairings was released; and it seems that these larger fairing halves will not be recovered.
The extended payload fairing
In physical size, SpaceX’s extended payload fairing maintains almost the exact same diameter as the standard fairing, while the extended Fairing allows an extra 17 feet of height for payloads. This change in size is basically what we expected. The longer fairings will allow Falcon Heavy to support missions with physically larger payloads like NASA’s lunar Gateway.
One notable exclusion from the extended payload fairing diagram is note number three, which references the recovery hardware that normally would take up some of the room within the fairings. For the extended payload fairing, they make no reference to recovery hardware.
This is not the only hint in the user’s guide that these fairings will be expended. On page 9 of the user’s guide, under Section 2.4 “Retention, Release and Separation Systems” they go into detail on the fairing separation mechanism. The reuseable standard fairing makes use of mechanical latches along the seam. They use a helium circuit that releases the latches and pneumatic pushers to deploy the fairings. The system on the extended fairings is very different.
The two halves of the extended fairing are fastened by a bolted frangible seam joint. To deploy the fairing, redundant detonators initiate a detonation cord contained inside an expanding tube assembly. The detonation causes the expanding tube to expand outwards and break the structural seam between the two fairings in a controlled and contained manner. Four pneumatic pushers facilitate positive-force deployment of the two halves. The use of a non- bolted clamshell interface between the payload fairing and the rest of the vehicle provides significant shock attenuation of the separation event, maintaining environments for the payload well within nominal payload requirements.SpaceX Falcon User’s guide
This detonation-based deployment mechanism is certainly a simpler system than the reusable deployment system used for standard fairings. The detonation system, however, is one-time use and lacks the repeatability of the pneumatic system.
Why wouldn’t SpaceX recover the fairings?
It’s not surprising that the extended payload fairings likely won’t be recovered. While it would be great, a whole new parachute recovery system would need to be built to adjust for the dramatically increased size and weight of the fairings. It would take a lot of additional development time, in addition to the required training and time for recovery teams. These teams could already be spread thin for a dual-droneship recovery. Even with the standard payload fairings, SpaceX has had a hard time recovering them. After regular catch attempts, SpaceX opted to let the fairing halves splash down then recover them from the water.
There are also very few payloads that will make use of the extended fairings. Beyond a few classified National Security launches and NASA’s lunar gateway, it is unlikely these fairing will be put to regular use (by SpaceX standards).
This larger payload fairing also opens up the possibility that Dream Chaser could be launched on a Falcon Heavy rocket. While Dream Chaser is meant to be launched on ULA’s upcoming Vulcan in 2022, the larger payload volume opens the possibilty for Dream Chaser to be adapted to fly on a Falcon.
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