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back to article NASA aims for Friday WISE up

NASA's Wide-field Infrared Survey Explorer, aka WISE, is scheduled to blast off on Friday from Vandenberg Air Force Base in California on its mission to "scan the entire sky in infrared light with a sensitivity hundreds of times greater than ever before". All being well, WISE will be carried aloft atop a Delta II rocket during a …

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Headmaster

What sort of meters?

Electricity meters, Gas meters, light meters? The public needs to know!

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Happy

Ah, two

These aren't the polar-bear sized thermos bottles you're looking for ...

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Boffin

about the height and weight of a big polar bear, only wider

Woohoo! A new standardised measurement. When can we expect to see it used more widely?

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Thumb Up

The bear - was it curled up or stretched out, ready to attack?

I think that all mass and linear dimensions should be expressed in polar bears. It does make things much more understandable, given the general public's familiarity with polar bear dimensions.

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In real units

1 polar bear is about 16Firkins

But with global warming and all the Polar bears melting it's not a very useful unit.

I was involved with it's predecessor WIRE launched almost exactly 10years ago.

Unfortunately just after launch somebody removed the lens cap and pointed it at the sun which didn't do it very much good.

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Joke

Standard Units

Allow me to clear these up for you using the El Reg standard measurement system (http://www.theregister.co.uk/Design/page/reg-standards-converter.html):

The standard unit of length shall be the EU standard (Florentine) linguine (unboiled at sea level), defined as 1lg, weight is measured in "Jubs" (naturally!)

So 2.85 Meters = 20.36 linguine tall by 14.28 linguine wide by 12.35 linguine deep with a weight of 157.38 Jubs

"2.85 meters tall (9.35 feet), 2 meters wide (6.56 feet), 1.73 meters deep (5.68 feet) and weighs 661 kilograms (1,433 pounds)".

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WTF?

wait a farking minute!

for the zillions of my tax dollars this no doubt cost, they couldn't do better than a 4MP camera (more accurately 4x 1MP, which might be even worse).

I mean, really. Lenses and stuff aside, surely they could have used higher res sensors? My crap phone has better than 1MP resolution. I can get a TEN megapixel camera for under US$100 now. Granted it's a crappy lens and crappy everything else, but it theoretically has 2.5 to 10 times the res of a $grillion research sat?

Anon because some pseudo-boffin or other wannabe will surely flame me.

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It's the sensitivty that counts

In the detector sensitivity is probably more important than the pixel count, given that they want to see dim objects. And if they're good about it, which I suspect they are, they'll be able to combine loads of 1 mega pixel images into a pretty high detail rendering.

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wow Martin 6 of WISE infamy....

http://en.wikipedia.org/wiki/Wide_Field_Infrared_Explorer ...you were not kidding. I especially like this part:

""The influx of power into the telescope caused the solid hydrogen cryostat to boil off all of its cryogen. As a result, the cryostat vent, now expelling gas at rates orders of magnitude higher than designed, acted as a tiny thruster rocket overwhelming the attitude control system and ultimately spinning the spacecraft up as high as 60 rpm."

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Consider yourself flamed

I was going to make a joke about the low pixel count but alas. Suffice it to say, your "crap phone" is probably shall we say "crap" at photographing "some of the darkest near-Earth asteroids and comets". You might want to research concepts such as "sensitivity" and "noise".

Btw does having studied physics at uni (albeit many years ago) make me a pseudo-boffin or ar wannabe.

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Happy

AC@2109

"for the zillions of my tax dollars this no doubt cost, they couldn't do better than a 4MP camera (more accurately 4x 1MP, which might be even worse)."

No doubt. Except your camera sensor works at 0.3-0.85microns, not the 3.4, 4.6, 12 and 22 microns this system is designed to see. They were built by Teledyne (who probably build by the 100s, or a couple of 1000 sensors a year). They can take about 8g and the odd soar flare or 2 and their packageing is designed to survive about -253c (-398F or thereabouts). NASA state WISE's last working predecessor sat (IAS) had 62 pixel sensors (presumably a scanning mirror to sweep the scene).

Those sensors will be susbstantally more expensive than the biggest SLR camera sensor.

And this wills tive give about a 60 fold improvement over what is already known.

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@AC@2109

It's thanks to things like this that you have a DSLR.

The first CMOS arrays ( the replacment for CCDs in most cameras) really got good for the infrared camera on Hubble.

About 15years ago they made a 1000x1000 array which cost $100K (with a 1-2um infrared sensor layer) and had noise comparable to a CCD.

1 MP camera at 22um is very very impressive at any price!

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Happy

WIRE is a nice sidelight on Hydrogen

Note that the sunlight *reflected* off the Earth was enough to vaporise *solid* hydrogen and spin it up to 60rpm

This is a few pc (IIRC) of what the sun actually emits onto the earth and a reminder that planning an H2 powered vehicle (beloved of Top Gear presenters) had better have either very strong (5000 psi) tanks or *very* good insulation as the volume change of LH2 to GH2 is about 1:700. If that does not worry advocates of this wonder fuel they should look up the phrase "fuel air explosive" along with "ignition temperature" and "explosive mixture limits"

IT Angle. The root cause was the pyro system used an Actmel FPGA to lower hadware package count, weight, volume etc. Turns out the I/O definitions and status are unreliable until for a while after power up. Some outputs (or inputs) normally putting out 0 (or 1) might put out their reverse. Bad news if one of those O/Ps was wired to a pyro device and went 1 (fire) when it had not been told to.

NB AFAIK this is not unique to Actmel parts but they are space rated and are one time programmable so don't need a seperate ROM to configure their on chip SRAM tables. Just one of those little differences between the EDA sim of a part andd real life.

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