Posted on 10/30/2020 12:45:32 PM PDT by BenLurkin
The capsule is scheduled to send up four astronauts no earlier than 7:49 p.m. Eastern time on November — a mission dubbed "Crew-1." It will be the first non-test, crewed mission since the successful crewed test flight in May 2020.
But ahead of the big launch, SpaceX vice president Hans Koenigsmann explained in a NASA briefing this week that a problem with a "nail polish"-like substance discovered during a previous launch threatened to derail the grand plans. The problem already caused NASA to delay the Crew-1 flight earlier this month.
The problem dramatically came to light during the GPS-III SV04 launch earlier this month, Koenigsmann said, when SpaceX stopped the October 2 launch with just two seconds till lift off.
The issue? Two of the engines attempted to start early. To find out what happened, the team removed the engines and took them to the McGregor test facility in Texas for further testing.
They found a component inside the gas generator – "basically like a little rocket engine" — that feeds propellant into the main chamber. The tests found a masking lacquer, left over from the build process, had blocked a vent hole.
The lacquer is used to mask components during the surface treatment. Koenigsmann speculated that some went into the vent during the washing or cleaning process.
Upon closer inspection, the team found the same issue on two of the Crew-1 booster's engines. The same problem also affects one engine for the booster to be used in the Sentinel 6 mission, which is scheduled to launch a satellite on November 10.
(Excerpt) Read more at inverse.com ...
Rocket science ping
“Inside the gas generator”
Nicknamed “Hillary”.
Oopsie. Someone forgot to wash off the PVA before assembly.
Recall some years ago Marine helicopters were falling out of the air because of de-laminating rotor blades
Was eventually traced to a laminating technician who would varnish her nails at beak time
The nail varnish vapor on the blades prevented proper adhesion.
We had to make a call and this was my first big leadership job so I went to the bigshots, VP of engineering on down they all said 'wow, that's a tough decision you have. Let us know what happens.' Thanks, guys. Lead from behind I guess. So it was all on me.
Knowing I could cook the transmitter and end my career, I said 'enough is enough, turn it on and let's radiate.' It was fine. But I aged five years in the meantime.
Not a robust system if it can be stopped with some misapplied nail polish (lacquer).
Sounds like a QA/QC problem.
Lacquer in the gas line.
I remember something like this clogging a carb on my motorcycle in 1974. As much as it seems silly, it stopped me in the middle of the woods.
We had one operator who wasn’t allowed in the photolithography line. Her perfume interfered with the photoresist...
"Let private industry do it cheaper" they said...
/s
Turns out that people who had aluminized christmas decorations at home were bringing the particles to work on their clothes and shoes. Even though we wore lab coats the particles were mobile enough to get into the air and mix with the conformal coat during the application process, the last step before final test.
We had a vapor phase degreaser that the gals in PCB assembly found worked wonderfully and much more quickly than cleaning by scrubbing.
Unfortunately, it’s real purpose was to clean stainless steel parts for penile implants, and left traces of flux on parts bound for the cleanroom.
Is that what you meant by engineer (hardware/firmware)?
A frozen o-ring took out the Challenger.
Not one Morton-Thiokol engineer signed off on that launch. Not a single one. It was approved by (presumably non-technical) managers.
How about them Bears!
Yeppers.
Ya make ‘em to ever closer and closer tolerances,
ya make lighter and stronger and lighter and stronger,
ya start makin’ ‘em too easy to be “just a little bit” wrong.
Cadmium playing on tools caused titanium to get brittle during development of the SR-71.
Some things just aren’t known in advance.
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