On 17 Jan 2004 09:10:10 -0800, (vthokie)
wrote:

Is the James Webb Space Telescope a (more or less) secure program at
this point?

More or less, but at this point it would not surprise me if any major
project is scrapped.

Has the design been finalized?

AFAIK, Yes.

Has construction begun?

It has started, but a long way to go yet. This telescope is due for
launch in August of 2011, which means that if it still early days if
NASA wants to cut or delay this project.

I'm guessing that it was intended from the start to go up on an
expendable launch vehicle, since I've heard no mention of any impact
on the program due to the shuttle's retirement. What type of orbit
will it be in?

1.5 million km from Earth at L2 Point.

It needs to be a long distance from Earth's atmosphere in order to
reach a very cold temperature required for it's work studying the very
early Universe.

Also, what is its expected lifespan?

5 to 10 years.

No servicing on this one, which is most likely a good thing, where
when it breaks that is the end of it.

It sounds like Hubble's rate sensing gyroscopes may be the determining
factor in its remaining life.

Yes, where they often fail and need replacing.

Obviously the new space telescope will
need something more reliable, since it's not designed for on-orbit
servicing. Would ring laser or fiber optic gyros provide more life
than the Hubble's mechanical gyros?

No idea what it is using, but even had it used Hubble's gyros, which
is unlikely I guess, then you can stick 8 of them on it to last the
expected 10 years.

Cardman
http://www.cardman.com
http://www.cardman.co.uk