NASA Universe-Watching Satellite Losing Its Cool 153
coondoggie writes "NASA this week said its Wide-field Infrared Survey Explorer, or WISE satellite is heating up — not a good thing when your primary mission instrument needs to be kept cold to work. According to NASA, WISE has two coolant tanks that keep the spacecraft's normal operating temperature at 12 Kelvin (minus 438 degrees Fahrenheit). The outer, secondary tank is now depleted, causing the temperature to increase. One of WISE's infrared detectors, the longest-wavelength band most sensitive to heat, stopped producing useful data once the telescope warmed to 31 Kelvin (minus 404 degrees Fahrenheit)."
It's warming up--pretty much on schedule (Score:5, Informative)
If you read the article it says that the solid hydrogen was expected to disappear about 10 months after launch, and it was launched in Dec 2009. Now it's 8/10.
What's so remarkable about something being used up that was designed to be used up?
Nothing to see here, move along!
--PM
Re:It's warming up--pretty much on schedule (Score:5, Informative)
NASA said WISE completed its primary mission, a full scan of the entire sky in infrared light, on July 17, 2010.
Sounds like a non-issue there.
Re:Orbit (Score:2, Informative)
depends on whether the primary source of the offending heat is internal or external.
(no i did not RTFA)
A real shame there. You didn't even read the summary. It's not really a source of offending heat that's the issue so much as a lack of proper cooling. The outer, secondary cooling tank is depleted. The primary one is still functional but apparently it's not enough to keep it at optimal temperature.
As Planned (Score:1, Informative)
It finished the first pass a month ago and will be doing another pass as it heats up to check for differences since the last pass.
The new infrared data provided by WISE should be approximately 1000 times more sensitive than previous data.
Re:So that's like... (Score:3, Informative)
I talk in English myself.
The entire British Commonwealth uses Celsius.
Re:So that's like... (Score:5, Informative)
Re:What to do (Score:4, Informative)
The primary mission was to map the whole sky once. They left themselves some reserves in case of problems, so they were expecting to be able to do a second partial map, but we covered their success [slashdot.org] when it happened back in July. So, this is news, but not a surprise. You can find more details on their site [nasa.gov].
Re:So that's like... (Score:3, Informative)
Astronomers use a hodge-podge of units in different systems. Cgs units are common, but for the really fun things we tend to use units like solar masses, parsecs, magnitudes, and foes (although that one never really caught on).
Re:So that's like... (Score:3, Informative)
So if your server is in Nashville, all text should be in a southern accent, rest of the country be damned?
Of course not, but I would logically expect the site's text to be in English.
If a US-based organization's data is released by way of a US-based website (Network World) to what I assume is mostly a US audience I'm not going to be surprised they used Fahrenheit. Celsius would have been nice for the rest of us but it's not hard to convert.
Re:Isn't space 'cold'? (Score:4, Informative)
It's heating up due to absorbing solar radiation and the operation of the electronics on board. Space is cold, but that doesn't help our poor telescope because there's nothing for its heat to be transmitted to. It's not like setting a hot mug of coffee outside on a cold winter day. There, conduction and convection are doing most of the work. Conduction, by the way, is why the sun hitting one side of the scope results in the entire telescope heating up.
In space the only effective way to lose heat is via radiation. The amount of blackbody radiation emitted is proportional to temperature, and the equilibrium point where the telescope is losing as much heat as it is gaining is well above 12K.