SpaceX armchair quarterbacking

I know I should probably wait for the official statement from spacex,
but I will speculate on the cause of the failure anyway.

I just looked at the video again after downloading it from
nasaspaceflight.

The insulating blanket they stuck on the first stage lox tank did not
peel off at launch like it was designed to do. It flapped around wildly
in the wind and peeled off bit by bit as the rocket accelerated.

They should have listened to the experts on this group. The insulation
was probably frozen to the tank as predicted by Henry Spencer:

http://groups.google.com/group/sci.space.policy/browse_frm/thread/7c755cc1a2bfd572/2364512cef7e1681?q=henry+spencer+lox+boiloff&rnum=2#2364512cef7e1681

Maybe they should employ him for his encyclopedic knowledge of space
history.

But that was not the real problem. All that flapping insulating blanket
did not seem to affect the trajectory of the rocket noticeably. It
might have become a problem at max Q, but they never got that far.

At about 25 seconds into the flight, you can see a huge flame bursting
out of the engine to the right. It is much too sudden and too big to be
engine gimballing, so it is probably a burnthrough of the ablative
chamber. This might have been caused by the blanket hitting the engine,
but I find this highly unlikely.

So probably it was a burnthrough of the ablative chamber. All these
flight readiness firings were probably not such a good idea after all.
But it might be that pintle injectors and ablative chambers are not a
good combination. Jon Goff has some very insightful thoughts on that
issue:

http://selenianboondocks.blogspot.com/2006/01/some-spacex-commentary.html

They are planning to replace the ablative chamber by a regen chamber.
Hopefully the merlin 1 regen is in an advanced state of development.
After all this trouble they had with the ablative pintle engine, they
might want to switch to a regen engine once and for all.

The whole incident emphasizes the importance of not only incremental
development, but also incremental tesing. Spacex have a very tight
connection between engineering and fabrication, and they also do a lot
of subsystem testing in house. So in these areas they are really doing
things right.

But when it comes to actual flight testing, their approach is not too
different to the old aerospace companies. That is really a pity, since
this failure mode would probably have occured in a test flight of just
the first stage on a ballistic trajectory with a reduced fuel load, so
they could have found out about this much earlier and without losing a
perfectly good upper stage and a payload. It would also have caused
much less embarrassment.

They really need the capability to do these kinds of tests without the
overhead of a real orbital mission. Maybe they should do suborbital
hops from the middle of the ocean launching from a ship. Jim Maser of
sea launch would certainly be helpful in setting up such an operation.

Anyway, the important thing is that they try again. If wernher von
braun had thrown in the towel after his first blown up A4, there would
never have been a moon landing.

I am certain that they will learn a lot from this launch, and they will
have better luck next time

.

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