In article ,
ess says...

On 18/10/2016 3:23 PM, Fred J. McCall wrote:
While they haven't confirmed it as the cause yet, the current leading
candidate for the cause of the explosion is SOLID oxygen forming in
the composite overwrapped pressure vessel that helium is stored in.

This is how it would work. For this flight SpaceX was apparently
trying to increase the degree of super-cryo chilling on the liquid
oxygen, so they were pumping it even colder than normal (close to
freezing point). Some of the super-chilled LOX could have gotten into
the COPV and then frozen. As tank pressure went up, the solid oxygen
could not be squeezed back out of the overwrap and detonated with the
carbon composite wrapping. This breeched the helium pressurization
tank, overpressuring the LOX tank and things go up from there.

SpaceX has not confirmed that this is their leading theory (or even a
theory). It is being reported as something that came out of a private
conversation with Musk and SpaceX says they have a policy of not
commenting on private conversations by Musk.

If that's really the problem, it makes a return to flight easier. Just
revert to the 'normal' amount of chilling that they used on previous
flights.



Customers might be less than happy with the idea that their production
launch vehicle is being experimented on, though the contract may allow
for that.

Sylvia, this quite often the case with SpaceX. It's still a young
company and is still optimizing Falcon 9. Unfortunately, when you push
the envelope like this, sometimes an "unknown unknown" bites you in the
ass.

But, look at the usual suspects. ULA has done very little in the way of
innovation related to the EELV's and costs still went up! Why is that?
You'd think if everything was "standardized", costs would come down, but
they didn't.

Orbital ATK is "innovating" a bit, but mostly by seeking out the lowest
bidders for the bits of their liquid fueled stage(es). The rest is
solid stages made in house. I *really* hate solids for launch. Too
much vibration, extremely violent failure modes, can't be economically
reused, and little chance that costs will ever drop by orders of
magnitude. So, on the "solids" side of the house, Orbital ATK isn't
innovating in a way that would ever reduce costs.

The other way to look at this is that if we never innovate, costs will
not come down by the orders of magnitude that is needed for the US to
become a truly space-fairing nation. That's really Musk's long term
goal, to send a truly huge number of people to Mars. This vision is in
stark contrast to NASA's "vision" of sending a handful of NASA
astronauts to Mars (citizens can apply, but will have a snowball's
chance in hell of becoming a NASA astronaut).

Jeff
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