The Falcon will rise again

SpaceX has released some information about the Falcon 9 mishap; they have managed to reproduce the failure condition on the ground at their Hawthorne, Texas test facility, purely by manipulating the helium load process.  So that’s good news, because it means there’s no hardware that needs redesign in order to return to flight.  Lots of hardware that needs repair at SLC-40 at Cape Canaveral, of course, but that’s not a showstopper since they still have SLC-4E at Vandenberg, and LC-39A at KSC is nearly ready.  It would appear that when they modified their procedures and requalified everything with the superchilled LOX loading, the one thing they didn’t fully analyze was their original helium loading procedure.  There’s something about it that is able to cause uneven heat distribution across the composite overwrapped pressure vessels (COPVs) that make up the helium tanks. COPVs are particularly vulnerable to issues with uneven heating, since their strength comes from the combined force of millions of wound fibers.  Disrupt just a few and the whole thing comes apart like a house of cards.  They are widely used in the industry, however, because of a very attractive combination of high strength and low mass.

With this in mind, SpaceX is now targeting mid-December for their return to flight, which is amazingly fast in this industry.  They are fortunate that it was not an equipment problem, and even more fortunate that they happen to have a spare launch complex; that’s a very unusual circumstance, so the timing was fortuitous.  It appears the return-to-flight mission will likely be the inaugural LC-39A flight, with Echostar 23, a commercial geosynchronous commsat, as the payload.

Meanwhile, this whole incident is raising additional questions with NASA’s astronaut office, wanting to fully understand whether it’s going to be safe to, for the first time in history, allow crew to board the vehicle before propellant loading.  NASA was aware of that practice prior to the accident, and had concerns even then, but not enough to ask SpaceX to preserve the lower-thrust Falcon 9 that doesn’t require late propellant loading, nor to ask them to accelerate the methane-burning Merlin variant.  So I personally suspect they will ultimately allow SpaceX to use Full Thrust Falcon 9 for crewed flights.  This is just giving the safety people more urgency with their questions.


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