JF Mezei wrote:

On 2017-04-17 21:45, Jeff Findley wrote:

Those are all tests of individual components. The first "all up" test
will be EM-1.


Once the thing has been assembled and perhaps at the pad, don't they
spend mucho time doing integration tests and simulations, test engine
firings etc?


No, they do none of that. The 'take the vehicle to launch ready' that
SpaceX does is very unusual. Usually the first time the vehicle gets
fueled is when you're going to light it off and fly.


Once it gets to EM-1 with an actual launch day/time announced and it
gets to that date, doesn't that mean NASA is confident it has worked out
the bugs and that the thing won't blow up in its face?


They certainly hope they have, but there is only one way to be sure
that the all up vehicle works and that is to fly it.


With modern computer simulations, doesn't that allow NASA to perform a
lot of validation before first first flight?


You can only simulate the stuff you know about.

snip trip to the weeds


--
"Some people get lost in thought because it's such unfamiliar
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