James Webb Space Telescope

[bknight]

In the recent thread with Neil Baker concerning the PLSS, one link to the massive NASA vacuum Chamber A leads me to a question.
http://www.nasa.gov/centers/johnson/engineering/integrated_environments/altitude_environmental/chamber_A/
In the link NASA is in the process of a reconstruction project to allow the James Webb Space Telescope to be tested in the chamber.  I wonder whether NASA learned from a huge past mistake in the Hubble Space Telescope to checking every detail so this won't be another black eye for them?
We won't have a way of going to the telescope with people at least to fix a mistake.  Perhaps robots could be programmed to do repairs.

[Luke Pemberton]

I wonder whether NASA learned from a huge past mistake in the Hubble Space Telescope to checking every detail so this won't be another black eye for them?

What black eye, are you referring to the problem with the correction to Hubble's mirror?

[bknight]

Yes, sir.

[Luke Pemberton]

Yes, sir.

Well, unless others here want to correct me, a vacuum test would not have picked up that error. The error in the mirror was due to a contractor rushing a step in the calibration of an interferometer.

http://carpetbomberz.com/2012/04/05/charlie-pellerin-on-leadership/

[bknight]

Well, unless others here want to correct me, a vacuum test would not have picked up that error. The error in the mirror was due to a contractor rushing a step in the calibration of an interferometer.

http://carpetbomberz.com/2012/04/05/charlie-pellerin-on-leadership/

Actually I wasn't thinking about a vacuum chamber test, the article said they were remodeling it to accommodate the telescope.  I was rather hoping the guys in charge would check out all the mirrors and alignments so we don't have a repeat of Hubble.
I guess I didn't have enough coffee when I penned that this morning.

[Luke Pemberton]

Actually I wasn't thinking about a vacuum chamber test, the article said they were remodeling it to accommodate the telescope.  I was rather hoping the guys in charge would check out all the mirrors and alignments so we don't have a repeat of Hubble.

I would would like to hope too that they learn lessons from the Hubble mirror problem. The JWST mirror is impressive and there are many different problems with its deployment compared to Hubble. I should imagine that the mirror polishing was overseen to avoid the quality control issues that almost ended Hubble before it started.

[bknight]

I would would like to hope too that they learn lessons from the Hubble mirror problem. The JWST mirror is impressive and there are many different problems with its deployment compared to Hubble. I should imagine that the mirror polishing was overseen to avoid the quality control issues that almost ended Hubble before it started.

I hold the same hope.  NASA has done remarkable missions, but every so often the smallest overlooked problem derails their performance. Not to throw stones but:
1. Miscalculation of distance parameters allows Mars probe to crach into the surface.
2. O-ring problems with the external SRB's didn't pose a significant threat to any mission until Challenger
3. Foam strikes observed on many/all(?) of shuttle launches didn't pose a threat until Columbia.
4. Mirror imperfections in Hubble even during 1-2 years in cold storage waiting for the Shuttle to regain flight status.
That's all I can remember at this time.

[Allan F]

5: Testing shoddy wiring and flammable materials in a high-pressure pure O2 atmosphere.

[bknight]

5: Testing shoddy wiring and flammable materials in a high-pressure pure O2 atmosphere.

Yes that was a biggie.

[smartcooky]

Yes, sir.

Well, unless others here want to correct me, a vacuum test would not have picked up that error. The error in the mirror was due to a contractor rushing a step in the calibration of an interferometer.

http://carpetbomberz.com/2012/04/05/charlie-pellerin-on-leadership/

I think he means just do some bloody testing before committing to launch.

Hubble was undone by budget cuts and pressure to finish the task. This resulted in short cuts being taken, and one of those short cuts was to not test the mirror. A simple focault test at ANY stage before the mirror was installed would have picked up the problems with the mirror's "figure". Even an amateur telescope maker wouldn't dream of installing his newly ground and aluminised mirror into the tube without doing a focault test.

[ka9q]

2. O-ring problems with the external SRB's didn't pose a significant threat to any mission until Challenger
3. Foam strikes observed on many/all(?) of shuttle launches didn't pose a threat until Columbia.

For these two at least, there were plenty of warnings before the disaster that simply went unheeded.

[bknight]

2. O-ring problems with the external SRB's didn't pose a significant threat to any mission until Challenger
3. Foam strikes observed on many/all(?) of shuttle launches didn't pose a threat until Columbia.

For these two at least, there were plenty of warnings before the disaster that simply went unheeded.

Yes these two had many occurrences, not a one off.  I was just trying to note where NASA, generally performing well in a rather hostile environment, seems to not check everything to ensure mission success from time to time.  Then  putting a whose checking the checker on the system.

[bknight]

The mirrors are being installed, here's hoping they did it correctly this time.
http://www.nasa.gov/press-release/nasa-s-webb-space-telescope-receives-first-mirror-installation

[bknight]

The mirrors are installed.
http://www.nasa.gov/press-release/nasas-james-webb-space-telescope-primary-mirror-fully-assembled
My question what testing for the next two years will be done?

[Dalhousie]

2. O-ring problems with the external SRB's didn't pose a significant threat to any mission until Challenger
3. Foam strikes observed on many/all(?) of shuttle launches didn't pose a threat until Columbia.

For these two at least, there were plenty of warnings before the disaster that simply went unheeded.

Yes these two had many occurrences, not a one off.  I was just trying to note where NASA, generally performing well in a rather hostile environment, seems to not check everything to ensure mission success from time to time.  Then  putting a whose checking the checker on the system.

The Galileo antenna would be another one, several issues with Curiosity come to mind (the drills, the wheels) come to mind as areas where more checking would have been good.