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Old May 16th 18, 08:20 AM posted to sci.space.policy
Fred J. McCall[_3_]
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Default First flight of Block 5 successful launch and landing

JF Mezei wrote on Tue, 15 May 2018
18:22:21 -0400:

On 2018-05-15 07:13, Jeff Findley wrote:


fins: had heard that the Falcon 9 Heavy was first to use them, but
your link proves otherwise.


What? You're not going to argue with him about it?



Pretty much everything you say is new is an incremental upgrade over
previous versions, so the likelihood of failure is rather low, IMHO.


Looking at the early failures, it was often "very close but no cigar".
So introducing lots of minor changes could be seen as major for the
landing software.


And monkeys could fly out your butt. Landing software is going to
care about physical characteristics. It's going to have tolerance for
mass changes because they need to be able to land with varying amounts
of fuel. So the only changes to really care about are CG and moment
arm changes. That's easy to design around on the ground.



Also, I'd bet that all of these changes have been reviewed by NASA as
part of commercial crew.


I have not seen the contract between NASA and SpaceX. Not sure how much
micromanagement authority they have. But for sure, they would have
specifcied a number of standards and succesful tests prior to NASA
sending their crews on SpaceX flights.


The commercial crew capability is being developed under NASA contract,
so they're going to get program reviews on changes.


If NASA is reluctant to accept on-going tweaks, that would push them to
agree to re-use of a rocket that is at a version NASA tested, instead of
insisting on always new stages which would force NASA to accept on-going
tweaks and improvements being made.


No.


--
"The reasonable man adapts himself to the world; the unreasonable
man persists in trying to adapt the world to himself. Therefore,
all progress depends on the unreasonable man."
--George Bernard Shaw