Why is the JWST so expensive?

[Flatlander]

Space Telescope to Cost $8.7bn

I'm sure Top Gear could do it for 10 and 6, chips and lard.
Space Shuttle on a budget.

[retina]

I though it was obvious.

$10m for the design
$10m for the telescope.
$10m for the launcher.
$10m for the control building.
$8.66b for bribes, political donations and lap dancers.

I thought every public project was like this?

[Flatlander]

Originally Posted by retina

I though it was obvious.

$10m for the design
$10m for the telescope.
$10m for the launcher.
$10m for the control building.
$8.66b for bribes, political donations and lap dancers.

I thought every public project was like this?

That explains it then.

[fivemack]

I can just about see how the cost went from three billion to nine billion; if you've got about five thousand engineers at $100,000 per year cost-with-overheads-and-materials each then each year's postponement adds half a billion dollars, and maybe the project's at that big a scale.

It's an edge-of-the-possible project - Hubble was quite similar to spy satellites of the time, I suspect JWST is in the same way similar to the now-cancelled Future Imagery Architecture project to build newer, better spy satellites.

[xilman]

Originally Posted by fivemack

Hubble was quite similar to spy satellites of the time

I do love good old British understatement.

HST is very nearly identical to the Keyhole satellites. The HST cameras being adapted to low-intensity imaging is by far the major physical difference. The direction in which it is pointed is the other major difference.

Question: why does the HST fit so snugly in the shuttle's payload bay?

Paul

[Christenson]

Originally Posted by xilman

I do love good old British understatement.

HST is very nearly identical to the Keyhole satellites. The HST cameras being adapted to low-intensity imaging is by far the major physical difference. The direction in which it is pointed is the other major difference.

Question: why does the HST fit so snugly in the shuttle's payload bay?

Paul

What do you think went up on those secret shuttle missions? It doesn't take a clearance to figure it out!

I'd think a KH satellite would also have some adaptive optics/wavefront correction equipment on board, though maybe the right approach in that case would be to take very short exposures (remember, lots of light half the time) and then process the results into still pictures.

[cheesehead]

Originally Posted by xilman

I do love good old British understatement.

:-)

Question: why does the HST fit so snugly in the shuttle's payload bay?

Since it, like the Keyholes, was designed from the start to be launchable by shuttle, that snug fit is simply a design spec. :-)

[xilman]

Originally Posted by Christenson

I'd think a KH satellite would also have some adaptive optics/wavefront correction equipment on board, though maybe the right approach in that case would be to take very short exposures (remember, lots of light half the time) and then process the results into still pictures.

True. That's the converse to my statement about low-light optics.

Paul

[Uncwilly]

Why was the mirror so perfect, yet in error? Maybe the blank met the right yet wrong spec.

[Christenson]

Originally Posted by xilman

True. That's the converse to my statement about low-light optics.

Paul

I have a different question:
NASA (and even the Hubble) seem to be prone to "Normal Accidents" (two shuttles preventably destroyed in flight, and some within the organisation acutely aware of the danger). The HST had a major "accident" with its mirror, the public story being about mis-assembly followed by a failure to do a foucault knife-edge test known to any amateur telescope builder worthy of the name.

Was the KH program plagued by similar problems, with similar nontechnical causes? Is the JWST program going to have the same problems -- you are busy calculating an engineering staff of thousands....

[xilman]

Originally Posted by Uncwilly

Why was the mirror so perfect, yet in error? Maybe the blank met the right yet wrong spec.

A small component in the test rig was inserted upside down.

Paul