Author Topic: James Webb Space Telescope  (Read 23227 times)

Offline 12oh2alarm

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Re: James Webb Space Telescope
« Reply #45 on: May 12, 2016, 12:55:53 PM »

... 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.

Shit happens. So much so, it fills an entire book:
Springer, "Space System Failures", by David M. Harland and Ralph Lorenz with chapters on

1. The Missiles
2. The Shuttle
3. Back to Expendables
4. Heavyweights
5. Lightweights
6. Boom and Bust
7. The Chinese Experience
8. The Current Crop
9. Failures and Redundancy
10. Propulsion System Failures
11. Attitude Control System Failures
12. Electrical Failures
13. Environmental Failures
14. Structural Failures
15. Failures on the Ground
16. Operator and Software Errors
17. Conclusions

One more example: if you don't follow the "Count the bolts before you tilt the platform, mate!" protocol, a mishap might happen.

Offline Trebor

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Re: James Webb Space Telescope
« Reply #46 on: May 13, 2016, 07:35:42 AM »
...
One more example: if you don't follow the "Count the bolts before you tilt the platform, mate!" protocol, a mishap might happen.
That's a bit embarrassing, you would think that checking your extremely costly bit of kit was actually attached to something before spinning it around would have been obvious.

Offline bknight

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Re: James Webb Space Telescope
« Reply #47 on: June 01, 2016, 01:41:30 PM »
One step closer! :)
http://www.nasa.gov/feature/goddard/2016/science-instruments-of-nasa-s-james-webb-space-telescope-successfully-installed

Science Instruments of NASA’s James Webb Space Telescope Successfully Installed
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Offline Dalhousie

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Re: James Webb Space Telescope
« Reply #48 on: June 04, 2016, 02:09:03 AM »
Still like Hank Green's video

Offline Glom

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Re: James Webb Space Telescope
« Reply #49 on: June 04, 2016, 05:10:48 AM »
I suppose after seeing that, I should get out of bed and get back to work on my science thing.

Offline godscountry

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Re: James Webb Space Telescope
« Reply #50 on: June 04, 2016, 02:33:16 PM »
Good point and lets not forget the loss of the 125 million dollar Mars Climate Orbiter spacecraft,due to the use of two different measuring systems by the engineering teams,one engineering team used the english system while the other team used the metric system,which resulted in navigational errors to the spacecraft.I would like to think NASA has implicated some new rules,along with a long list of QC checks.With a budget of 1/2 of one percent,you can't afford losses like that.

Offline bknight

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Re: James Webb Space Telescope
« Reply #51 on: June 04, 2016, 04:00:21 PM »
I suppose after seeing that, I should get out of bed and get back to work on my science thing.

Instead of the insurance, health, infrastructure thing?
Truth needs no defense.  Nobody can take those footsteps I made on the surface of the moon away from me.
Eugene Cernan

Offline ka9q

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Re: James Webb Space Telescope
« Reply #52 on: June 05, 2016, 03:56:05 AM »
The specific units that were confused during Mars Climate Observer were those of force -- the thrust of the attitude control thrusters. They were used in a model to estimate the unwanted perturbations on the trajectory as a result of various attitude changes. The thruster manufacturer specified them in pounds-force and JPL interpreted them in newtons. A pound is bigger than a newton, so this underestimated the effect.

The spacecraft was on a collision course with the Martian atmosphere. The trajectory seemed off and the staff asked for more tracking time but was turned down by management. Had the extra tracking been done, they would have confirmed the problem with enough time to fix the problem.

Offline Peter B

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Re: James Webb Space Telescope
« Reply #53 on: June 05, 2016, 04:54:38 AM »
http://spectrum.ieee.org/aerospace/robotic-exploration/why-the-mars-probe-went-off-course

Superb article by James Oberg which details the problems with the spacecraft - or, more precisely, people and processes within JPL.

Offline smartcooky

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Re: James Webb Space Telescope
« Reply #54 on: June 05, 2016, 06:31:47 AM »
http://spectrum.ieee.org/aerospace/robotic-exploration/why-the-mars-probe-went-off-course

Superb article by James Oberg which details the problems with the spacecraft - or, more precisely, people and processes within JPL.


What a complete and utter cock-up!!!

A multi million dollar probe was lost because people didn't fill in the correct forms.... that's bureaucrats for you!!!
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Offline bknight

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Re: James Webb Space Telescope
« Reply #55 on: June 05, 2016, 07:50:44 AM »
This reminds me of a favorite saying in my profession:
Companies NEVER have enough money to perform an operation the right way, but they ALWAYS have enough money to fix the problem that was caused.
Truth needs no defense.  Nobody can take those footsteps I made on the surface of the moon away from me.
Eugene Cernan

Offline BazBear

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Re: James Webb Space Telescope
« Reply #56 on: June 05, 2016, 03:28:47 PM »
This reminds me of a favorite saying in my profession:
Companies NEVER have enough money to perform an operation the right way, but they ALWAYS have enough money to fix the problem that was caused.
Penny wise, dollar/pound foolish.
"It's true you know. In space, no one can hear you scream like a little girl." - Mark Watney, protagonist of The Martian by Andy Weir

My Youtube Apollo playlist http://www.youtube.com/watch?v=8SfyE9qsG8k&list=PL2aEC7cUMrGCNrtGMMWRXYob-kqCz2zz8

Offline Allan F

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Re: James Webb Space Telescope
« Reply #57 on: June 05, 2016, 06:39:36 PM »
http://spectrum.ieee.org/aerospace/robotic-exploration/why-the-mars-probe-went-off-course

Superb article by James Oberg which details the problems with the spacecraft - or, more precisely, people and processes within JPL.

Just like Apollo 1, Challenger and Columbia.
Well, it is like this: The truth doesn't need insults. Insults are the refuge of a darkened mind, a mind that refuses to open and see. Foul language can't outcompete knowledge. And knowledge is the result of education. Education is the result of the wish to know more, not less.

Offline smartcooky

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Re: James Webb Space Telescope
« Reply #58 on: June 05, 2016, 07:48:36 PM »
http://spectrum.ieee.org/aerospace/robotic-exploration/why-the-mars-probe-went-off-course

Superb article by James Oberg which details the problems with the spacecraft - or, more precisely, people and processes within JPL.

Just like Apollo 1, Challenger and Columbia.


I agree, all avoidable tragedies.

This is especially so of Challenger as administrators in NASA ignored repeated warnings from Engineers that launching in freezing temperatures was dangerous. It was only a piece of blind luck (a small piece of aluminium oxide sealing a leak at the last moment) that prevented STS-51L from exploding right there on the launch pad.

In particular, fluid dynamics engineer Roger Boisjoly correctly predicted that the O-Rings would fail in the freezing temperatures. He was ignored, and that decision cost seven astronauts their lives.

In a further insult to Boisjoly, he was treated abysmally by his bosses and colleagues at Morton-Thiokol for telling the truth about what happened.

For mine, the Challenger disaster remains as one of the most disgraceful examples in spaceflight of bureaucratic negligence, right from the political pork-barrelling that resulted in the SRB's being made in Utah and needing to have O-Rings in the first place (a design compromise so that they could be transported to the Cape) to the ignoring of repeated warnings about the SRB's safety in cold conditions.
► What you can assert without evidence, I can dismiss without evidence
► When you argue with idiots you risk being dragged down to their level and beaten with experience.
► Conspiracism is a shortcut to the illusion of erudition

Offline ka9q

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Re: James Webb Space Telescope
« Reply #59 on: June 05, 2016, 07:53:02 PM »
I think the Columbia disaster was worse. The technical details of the failure were different but the management failures were the same. They didn't learn from Challenger.