JF Mezei wrote on Wed, 16 May 2018
04:32:49 -0400:

On 2018-05-16 03:20, Fred J. McCall wrote:

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.


If it were that easy, they would have succeeded with their first
attempt. It took a number of attempts before they got it to work.


You're confused (as usual). Doing it the first time is hard. However,
once you've figured it out, so long as you don't make major changes in
CG or mass you don't even have to change the software.


The fact they succeeded on first attempt with a rocket where many
variables were changed shows the software has gained maturity and
reliability.


Or it shows that they took care that their changes didn't make any
significant changes in CG or moment arms.


Remember that the "revolutionary" part starts with Block 5 which can be
reused more than once, and this depends on reliable landings.


Remember that if the issue was 'reliable landings', they were already
doing that. The Block 5 changes are to reduce need for refurbishment
and make it easier when it is required.



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


Yet, weren't you the one arguing that a commercial crew contract was no
different than putting their employees on a commercial jetliner?


No, I wasn't. Once again you are confused. What I was arguing was
that a commercial crew contract ON AN ALREADY EXISTING AND FAA
CERTIFICATED VEHICLE is no different from getting on a commercial
airliner. But this is not that. This is development of a vehicle and
system under NASA contract to carry NASA personnel AS CREW. No FAA
certificate; NASA controls the 'man rating' of the system.


--
"Some people get lost in thought because it's such unfamiliar
territory."
--G. Behn