David Spain wrote on Thu, 18 Jul 2019 08:39:31
-0400:

On 7/16/2019 7:33 PM, Fred J. McCall wrote:

One story I read indicated (by an ex-SpaceX engineer) that it was for
reusability, as burst valves would have to be replaced (with some
difficulty) after any pressurization of the escape system. Some
reports also made it sound as if the titanium parts were only used on
the fuel side and if there had been no backflow everything would have
^^^^^^^^^^^^^

been fine (and we know they've successfully done this before). This
is sort of supported by reported SpaceX comments that they had no
reason to suspect this could happen.


Fred just a nit, but I think you meant to write on the helium side...


Actually I meant what I wrote but it's a little unclear. Yes, the
oxidizer was on the 'helium side', but it was at the check valve to
the fuel system.


--
"Insisting on perfect safety is for people who don't have the balls to
live in the real world."
-- Mary Shafer, NASA Dryden