Technical, Cost Issues Persist For Webb Telescope

"Conceived in the late 1990s as a follow-on to the Hubble
Space Telescope, JWST was projected to cost just $1 billion
to build and launch an observatory so advanced it would
revolutionize scientific understanding of star and planet
formation and identify galaxies in the early universe.

By 2011, however, the program had seen almost a decade of
cost overruns and schedule delays. Under pressure from
lawmakers, NASA rebaselined the program with a revised
cost estimate of $8.8 billion, a new launch date of October
2018, and a healthy amount of schedule margin to maintain
both. At nearly nine times the original cost, and more than
a decade behind schedule, JWST was finally on track.

Since then, the program has entered a critical phase; myriad
technical concerns have emerged, including mass issues on the
spacecraft, delayed delivery of two instruments and technical
problems with key subsystems, one of which required the
addition of a third round of lengthy cryo-vacuum testing to
the Integrated Science Instrument Module (ISIM). Combined,
these issues have cost 18 of 26 months of schedule reserve on
the ISIM, the heart of the telescope that houses JWST's four
instruments, designed to detect light from distant stars and
galaxies."

See:

http://www.aviationweek.com/Article....p26-598195.xml

when it launches will it even work?

: bob haller
: when it launches will it even work?

Why do you never ask that for your own pet projects?
Anything of which you disapprove is rife with faulty faultiness...
anything of which you approve has no risks.

Quite the double standard you employ, there.

I asked when it launches will it even work because its super highly copmplex, full of brand new designs, and worse it cant be serviced........

so if it fails somehow theres no fixing it

On 7/22/2013 5:52 PM, bob haller wrote:
I asked when it launches will it even work because its super highly copmplex, full of brand new designs, and worse it cant be serviced........

so if it fails somehow theres no fixing it

This seems like a fair question to me. Is it safe to assume that the
Webb telescope will be more complex than the Hubble? If so, then ask
yourself; why is the Hubble still up there doing its job? Could it be
because we HAD the ability to make multiple trips to fix it and upgrade
it? Do you realize how useless the Hubble was with its original faulty
optics?

So if we put this hugely expensive Webb telescope up there, how long
will it be able to do serious science before something goes wrong? We
will have no way to fix it.

In article ,
says...

when it launches will it even work?

When will you learn to read what's available instead of asking vague,
inane questions?

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer

In article ,
says...

On 7/22/2013 5:52 PM, bob haller wrote:
I asked when it launches will it even work because its super highly copmplex, full of brand new designs, and worse it cant be serviced........

so if it fails somehow theres no fixing it

This seems like a fair question to me. Is it safe to assume that the
Webb telescope will be more complex than the Hubble? If so, then ask
yourself; why is the Hubble still up there doing its job? Could it be
because we HAD the ability to make multiple trips to fix it and upgrade
it? Do you realize how useless the Hubble was with its original faulty
optics?

So if we put this hugely expensive Webb telescope up there, how long
will it be able to do serious science before something goes wrong? We
will have no way to fix it.

Depending on how you run the numbers, "fixing" Hubble was of dubious
economic value compared to simply building another copy with a properly
ground primary mirror, "fixed" solar arrays, and another copy of the
instruments and then launching it.

The only reason Hubble was serviced was because shuttle was funded, so
using it for servicing seemed like a good idea at the time. It still
needed the new arrays, and a "fix" for the spherical aberration in the
primary mirror, which wasn't terribly easy.

Also, other fixes to Hubble were made to systems not designed to be
repaired in orbit. Who's to say that the same can't be done to Webb
using SLS/Orion? After all, if you use the same sort of accounting used
for Hubble, the SLS/Orion, what's the difference?
Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer

Webb isnt designed to be serviced in orbit at all, and besides servicing would require a one off special service vehicle, unlike hubble and shuttle which was already available.

and even if the shuttle was still flying webbs orbit would be too high for shuttles

In article ,
says...

Webb isnt designed to be serviced in orbit at all, and besides servicing
would require a one off special service vehicle, unlike hubble and
shuttle which was already available.

I wasn't saying servicing Webb would be economical, or even a good idea,
but it would be possible (if Orion ever does fly on SLS). Besides, with
nowhere else for SLS to send Orion (moon and Mars are currently not
funded), NASA might just decide, "why not?".

In terms of what to use it for, SLS/Orion is space shuttle all over
again.

Jeff
--
"the perennial claim that hypersonic airbreathing propulsion would
magically make space launch cheaper is nonsense -- LOX is much cheaper
than advanced airbreathing engines, and so are the tanks to put it in
and the extra thrust to carry it." - Henry Spencer

probably easier to move it back to earth orbit if any complex repairs are needed, since it wasnt built to be serviced