The Most Sophisticated Mirror in the Universe

Hank summarizes the five reasons why infrared telescopes were supposed to be impossible to build, and then describes how a team of scientists and engineers overcame those obstacles to build the James Webb Space Telescope.

Many thanks to Scott Willoughby and the entire team at Northrop Grumman for the tour.

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A note re: gold from Dr. Amber Straughn of NASA - “Gold is not the only “reddish” elemental metal (Copper is even more reddish) and other metal alloys are reddish or yellow (e.g., bronze, brass). The point is simply that gold is an excellent reflector of ALL the wavelengths of light that Webb is designed to see—from 0.6 microns out to 27 microns. Gold happens to look gold to us because it reflects blue light poorly, but this doesn’t matter because Webb doesn’t see light shorter than visible red. Silver is also an excellent reflector of IR, but it’s not as good as gold at ALL the wavelengths that Webb will observe.”

And re: the mirror - while the individual mirror segments have been completed, the full-size mirror has not yet been fully assembled and tested.  And though “polishing a 6.5m continuous mirror is incredibly difficult, it is not technically “impossible.”  In fact, a team at REOSC in France and at the mirror lab at U of AZ have been casting and polishing 8.4m optical primary mirrors for years now. But making the mirror in segments, in addition to making it deployable, makes polishing the mirror an easier-to manage process—basically polishing 18 small mirrors vs. one huge one, especially considering it is a mirror for an IR telescope operating at cryogenic temperature and enables easier transportation during the polishing and construction process (it’s really difficult, time-consuming and expensive to move a monolithic 8.4m primary—akin to moving the whole Webb observatory).”

From Kepler to Webb: The History of the Telescope

Hank regales us with the history of the telescope, and then introduces us to some folks from the team who are working on the newest telescope in the chronology - the James Webb Space Telescope, an infrared telescope due to launch in 2018.

Thanks to the team at Northrop Grumman for allowing us the privilege of touring their facility, and to the scientists at NASA Goddard Space Flight Center for their help with this video.

ikenbot:

crookedindifference:

NASA Gets Two New Hubble Telescopes — Absolutely Free

All good things must come to an end, though. The shuttle is flying no more, and within the next couple of years, the aging telescope will gradually wink out too. It will be a terrible loss to science, and it kind of makes you wish someone had a spare Hubble secretly stashed away, just waiting to be unpacked and sent into orbit. That’s what would happen in the Hollywood version, anyway.
But it turns out that it is happening in real life too. The National Science Foundation has just revealed the existence of not one but two pristine, Hubble-class space telescopes still in their original wrappings in a warehouse in Rochester, N.Y. The pair was originally built for the National Reconnaissance Office, the agency in charge of spy satellites, to look down at Earth rather than up into space. But the NRO has moved on to bigger and better instruments, and decided to hand the telescopes over. “It just blew me away when I heard about this,” says Princeton astrophysicist David Spergel, a member of the National Academy of Science’s Committee on Astrophysics and Astronomy. “I knew nothing about it.”
The unexpected gift has sent NASA and the astronomical community, both of which have learned to live with smaller budgets and lower expectations in recent years, into a mild state of shock. It’s not clear what they’ll do with this astonishing gift — and indeed, even among the handful of scientists who have been in on the secret, there’s only a general consensus on how they might use just one of the telescopes, never mind both.
But while the free scopes are essentially there for the taking, there are a lot of hurdles to overcome. The cost of adapting cameras and other instruments to the rest of the components, then launching the whole thing and operating it for years won’t be insignificant. “A 50% discount still means you have to come up with the other 50%,” says Spergel. Still, getting the new scope into space should at least be cheaper than it was to launch the Hubble. “Hubble,” he says, “is really a 1960s-era telescope. It’s very heavy and fairly long. This one will be lighter and smaller.” Even with drastic upgrades, Hertz says, it’s plausible that it would cost just $1 billion to adapt and launch the proposed WFIRST — an absurdly low figure for such a powerful machine.
As for the second free telescope, the consensus so far, says Spergel, is that “we wait until sometime in the 2020s to decide what to do with it.” At the moment, the James Webb Space Telescope, the Hubble’s official successor, is eating up the lion’s share of NASA’s science budget, and even at a discount, there’s no way the agency can move ahead with both of the unexpected freebies at once.

I sure hope this doesn’t kill the James Webb Space Telescope.

I’m with shah on this one, I was already getting pretty amped about the JWST. It seems so promising.

I don’t think there’s too much chance of them scrapping Webb, given what they’ve already invested in it and the fact that it is not just a replacement for Hubble, but its successor.  Webb operates differently - as an IR telescope, rather than an optical or UV telescope like Hubble (though Hubble does have some IR capability) - and has a much larger mirror than Hubble, so it can see more and farther.  
There’s a good summary of the comparison between the two telescopes here: http://www.jwst.nasa.gov/comparison.html
But it’s super cool that they found two secret Hubble telescopes stashed away! What else could the spies be hiding? 

ikenbot:

crookedindifference:

NASA Gets Two New Hubble Telescopes — Absolutely Free

All good things must come to an end, though. The shuttle is flying no more, and within the next couple of years, the aging telescope will gradually wink out too. It will be a terrible loss to science, and it kind of makes you wish someone had a spare Hubble secretly stashed away, just waiting to be unpacked and sent into orbit. That’s what would happen in the Hollywood version, anyway.

But it turns out that it is happening in real life too. The National Science Foundation has just revealed the existence of not one but two pristine, Hubble-class space telescopes still in their original wrappings in a warehouse in Rochester, N.Y. The pair was originally built for the National Reconnaissance Office, the agency in charge of spy satellites, to look down at Earth rather than up into space. But the NRO has moved on to bigger and better instruments, and decided to hand the telescopes over. “It just blew me away when I heard about this,” says Princeton astrophysicist David Spergel, a member of the National Academy of Science’s Committee on Astrophysics and Astronomy. “I knew nothing about it.”

The unexpected gift has sent NASA and the astronomical community, both of which have learned to live with smaller budgets and lower expectations in recent years, into a mild state of shock. It’s not clear what they’ll do with this astonishing gift — and indeed, even among the handful of scientists who have been in on the secret, there’s only a general consensus on how they might use just one of the telescopes, never mind both.

But while the free scopes are essentially there for the taking, there are a lot of hurdles to overcome. The cost of adapting cameras and other instruments to the rest of the components, then launching the whole thing and operating it for years won’t be insignificant. “A 50% discount still means you have to come up with the other 50%,” says Spergel. Still, getting the new scope into space should at least be cheaper than it was to launch the Hubble. “Hubble,” he says, “is really a 1960s-era telescope. It’s very heavy and fairly long. This one will be lighter and smaller.” Even with drastic upgrades, Hertz says, it’s plausible that it would cost just $1 billion to adapt and launch the proposed WFIRST — an absurdly low figure for such a powerful machine.

As for the second free telescope, the consensus so far, says Spergel, is that “we wait until sometime in the 2020s to decide what to do with it.” At the moment, the James Webb Space Telescope, the Hubble’s official successor, is eating up the lion’s share of NASA’s science budget, and even at a discount, there’s no way the agency can move ahead with both of the unexpected freebies at once.

I sure hope this doesn’t kill the James Webb Space Telescope.

I’m with shah on this one, I was already getting pretty amped about the JWST. It seems so promising.

I don’t think there’s too much chance of them scrapping Webb, given what they’ve already invested in it and the fact that it is not just a replacement for Hubble, but its successor.  Webb operates differently - as an IR telescope, rather than an optical or UV telescope like Hubble (though Hubble does have some IR capability) - and has a much larger mirror than Hubble, so it can see more and farther. 

There’s a good summary of the comparison between the two telescopes here: http://www.jwst.nasa.gov/comparison.html

But it’s super cool that they found two secret Hubble telescopes stashed away! What else could the spies be hiding?