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NASA Debates How And When To Kill Hubble Telescope
Amy's Robot writes "The Washington Post reports that after 13 years of wear and tear, the Hubble telescope may be on the way out. NASA and some outside scientists have become involved in a heated debate about how and when to end the Hubble telescope program. Keeping Hubble in service until 2020 would require an extra maintenance visit by astronauts at a cost of at least $600 million. Some even worry the batteries could fail by 2010, since the next maintenance visit has been delayed by the Columbia accident and space station priorities. Is it worth maintaining our old friend Hubble, or should NASA let him go out in a blaze of glory?"
Hubble is a very upkeep-intensive device. Only very good engineering lets it last the length of time that it does between servicing missions.
Even if you don't upgrade the equipment, there is servicing that needs to be done. The biggest problem in the past has been the reaction wheels; they have spares but they DO fail. At one time they were one failure away from not being able to control the scope.
If you ARE going to go up and replace a few reaction wheels though, you might as well cart along an extra new instrument or two; no point in boosting to orbit and not bringing along new toys.
Lunar observatory? How 'bout the James Webb Space Telescope, slated to launch on August 2011.
According to the JWST Website, the next generation space telescope will cost "$824.8 million". What were you saying about comparative cost, again?
It looks like they were planning on bringing it back..
"Before the Columbia accident, NASA intended eventually to have a crew of astronauts maneuver the 43-foot-long telescope into a cargo bay and bring it home for installation in the National Air and Space Museum as an inspiration for future generations. A general unwillingness to subject astronauts to such risks for a museum exhibit, among other things, eliminated that option, Weiler said. "
but I know... that's from the second page : )
The Hubble Telescope has a 2.4 meter primary mirror (it's a Ritchey-Critien type Cassegrain design). Hubble's successor is currently in development and will have a 6-meter multi-cell primary mirror. This will give the James Webb telescope roughly 25 times the light-gathering ability of Hubble. Improved electronics will let the new telescope resolve objects about 400 times fainter than Hubble.
What's more, the new telescope will not be in low Earth orbit like Hubble. Instead, it'll reside at the L2 Lagrange point which is about 1.5 million KM from Earth. This means it's a one-shot deal. It has to work right the first time: there won't be any manned repair missions. One of the benefits of sitting at the L2 point is that it can be oriented so that one side always faces the sun...put a good solar shield on that side of the telescope and the rest of the telescope will remain frigid...essentially, you get a cryogenic cooling system for free.
Why visible light? One of the great advantages of a space-based telescope is it's wonderful resolving power (although, with adaptic optics, ground-based observatories are getting damned impressive), which allows it to observe very deep sky objects. And, due to redshift, the deepest observations that will be made will be in the infrared and far infrared. So, it seems to me that, in order to explore the ancient universe, it makes more sense to have a telescope with a sensitivity centered closer to the infrared end of the spectrum. Moreover, in order to explore objects deep in our own galaxy, or on the other side of the galactic plane, the only option is infrared observations.
Frankly, IMHO, the obsession with true-color images has more to do with public relations than true science. After all, some of the most interesting, recent discoveries have been in the ultra-long wavelengths (eg, WMAP) and the ultra-short (eg, Chandra).
It isn't, actually. The Hubble weighs about 24,000lbs, and the shuttle can bring down about 43,500.
This article sums up the scientific value of Hubble so far: http://news.bbc.co.uk/2/hi/science/nature/3115159. stm