NASA's WISE begins scanning sky.

[MKSheppard]

NASA infrared survey returns first snap
By Lester Haines • Get more from this author
Posted in Space, 7th January 2010 11:34 GMT

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NASA's Wide-field Infrared Survey Explorer (WISE) has returned its first photograph - a calibration shot of "about 3,000 stars in the Carina constellation":

NASA explains* that the eight-second exposure was "captured as the spacecraft stared in a fixed direction, in order to help calibrate its pointing system". Once fully up and running, WISE will "scan the sky continuously as it circles the globe, while an internal scan mirror counteracts its motion".

William Irace, the mission's project manager at NASA's Jet Propulsion Laboratory , said: "Right now, we are busy matching the rate of the scan mirror to the rate of the spacecraft, so we will capture sharp pictures as our telescope sweeps across the sky."

Operating at an altitude of 525km, WISE will pass over the poles 15 times a day taking a picture every 11 seconds through its 40-cm (16-inch) telescope. It will eventually deliver around 1,500,000 images of the entire sky in the infrared "with a sensitivity hundreds of times greater than ever before".

NASA expects to spot "millions of hidden objects, including asteroids, 'failed' stars and powerful galaxies". The data will serve as "navigation charts for other missions, such as NASA's Hubble and Spitzer Space Telescopes, pointing them to the most interesting targets the mission finds".

Since WISE's infrared-spying capability depends on it not emitting any detectable infrared light of its own, its scope and four one million-pixel infrared detectors are chilled to as low as 8 Kelvin in a frozen-hydrogen-filled cryostat (see pic).

NASA has described the cryostat as resembling "a giant Thermos bottle" or "the Star Wars robot R2-D2", and being "about the height and weight of a big polar bear, only wider".

The agency's big polar bear in this case is 2.85 metres tall, 2 metres wide, 1.73 metres deep and weighs 661kg.

The spacecraft's mission will end once the hydrogen evaporates away, by around October 2010, according to NASA's estimate.

[Mayabird]

It's too bad that we can't replenish the hydrogen supply. It'd be nice to keep it going, take a lot more pictures, or pictures of the same places later to see if there are any differences. Though I do wonder what'll happen to WISE once the mission is complete - I hope it won't be deorbited, and it was built with the hopes that maybe they could put in another tank in later to restart it. Always makes me think of the Martian rovers which were only supposed to last for 90 days but are still running after however many years it's been.

[MKSheppard]

This is what grabbed my attention:

NASA expects to spot "millions of hidden objects, including asteroids, 'failed' stars and powerful galaxies". The data will serve as "navigation charts for other missions, such as NASA's Hubble and Spitzer Space Telescopes, pointing them to the most interesting targets the mission finds".

We need more space based sensors looking OUTWARDS, to prevent us from getting whacked with another dino killer.

[cosmicalstorm]

Yes that always baffled me considering how much money is spent on monitoring hostile nuclear forces and what not, asteroids have exactly the same kind of ability to fuck things up.

I wonder what is most likely to happen over the next fifty years; that we will have a nuclear war/nuclear terror attack or that an asteroid capable of causing nuclear bomb sized devastation will fall down on a populated area?

Hopefully neither, of course.

[starslayer]

I wonder what is most likely to happen over the next fifty years; that we will have a nuclear war/nuclear terror attack or that an asteroid capable of causing nuclear bomb sized devastation will fall down on a populated area?

Nuclear war and/or terror attack, by a mile. Tunguska sized asteroid impacts are once a century events to begin with, and they can hit anywhere on the planet. One landing in a populated area is extremely unlikely, considering how little land area cities cover in the scheme of things.

Though I do wonder what'll happen to WISE once the mission is complete - I hope it won't be deorbited, and it was built with the hopes that maybe they could put in another tank in later to restart it.

The tank is the entire outside of the telescope, as you can see from the picture in the article Shep posted. There is no way short of bringing the entire thing back down on a Constellation in maybe 10 years' time that the cryostat could be replaced. WISE is a survey mission anyway; it's usefulness ends after its initial mission is complete, unlike the rovers you mentioned.