Herschel: the first science highlights |
Herschel: the first science highlights |
Apr 30 2013, 04:45 PM
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#16
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Member Group: Members Posts: 124 Joined: 20-April 05 Member No.: 291 |
They've announced the end of mission now that coolant has run out.
Probably a stupid question, but I'm guessing that the wavelengths being observed are too far into the infrared to allow a warm mission, ala Spitzer? Seems like a lack of foresight (or penny pinching) to put up such a huge mirror, and not leave any instruments that could take advantage of it in an extended mission. EDIT: and let me answer my own question: http://isnerd.me/2013/04/04/some-more-ques...rning-herschel/ QUOTE For a telescope operating at shorter wavelengths (about ten times longer in wavelength than visible light) a “warm mission” is feasible. This could have been done with Herschel, but it would have required that the surface of the telescope be made far more precise and smooth. That would have made it very much more expensive, leaving less money available for the rest of the spacecraft and the instruments. Any space mission must be built within a certain budget, and it is usually best to design it to be as effective as possible for a certain wavelength range. Herschel actually covers a very wide range – from 55 to nearly 700 microns in wavelength. That’s more than a factor of ten, which is very impressive. To make a warm mission possible would have meant making the telescope good enough to work at ten times shorter wavelength, and adding a fourth instrument. |
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Apr 30 2013, 04:58 PM
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#17
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Senior Member Group: Members Posts: 1729 Joined: 3-August 06 From: 43° 35' 53" N 1° 26' 35" E Member No.: 1004 |
by the way, the radiation monitors are still useable, and there was a proposal to keep them on. hope they will do it...
http://herschellife.blogspot.es/1342197754...-end-of-helium/ QUOTE The ESA Space Weather Team is keen to maintain Herschel operational as long as possible because of the information that it provides on the radiation environment in Deep Space. Herschel will finish observing just as we reach solar maximum, so any time that it can spend after solar maximum will be a tremendous bonus, particularly if it could observe for a full solar cycle. For this, it does not matter of Herschel is in the Earth-Sun L2, the Earth-Moon L2, or in heliocentric orbit: the environment is similar and totally different to that in low-Earth orbit, where most satellites are, protected by the Earth’s magnetic field.
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May 18 2013, 10:22 AM
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#18
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Senior Member Group: Members Posts: 1729 Joined: 3-August 06 From: 43° 35' 53" N 1° 26' 35" E Member No.: 1004 |
some updates from Herschel's twitter account (https://twitter.com/ESAHerschel)
QUOTE Through the night of May 13/14 Herschel's thrusters fired for over 7 hours to put it into a non-return trajectory outside the Earth's orbit. QUOTE @ESAHerschel will now drift away from Earth, while continuing to work on technology tests into June. QUOTE Where is @ESAHerschel now? At midnight it was 1862398km from Earth and moving away at a leisurely pace, now working on SPIRE tests. QUOTE Around 15:30UT this afternoon HIFI was finally switched off after (almost) 4 years work in space. SPIRE is the last instrument left on. meanwhile, monitoring of solar radiation using the SREM instruments continue. particles from a flare in sunspot group 1748 were recorded the past week http://proteus.space.noa.gr/~srem/herschel...2013_P_flux.png |
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Jul 29 2013, 06:46 PM
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#19
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Senior Member Group: Members Posts: 1729 Joined: 3-August 06 From: 43° 35' 53" N 1° 26' 35" E Member No.: 1004 |
Herschel observations of comet Honda-Mrkos-Pajdusakova (see post #4) have been published in arXiv today:
A Herschel Study of D/H in Water in the Jupiter-Family Comet 45P/Honda-Mrkos-Pajdusakova and Prospects for D/H Measurements with CCAT very interesting. while most comets have D/H ratios unlike that of water in the Earth's oceans, comet HMP and Hartley 2 have Earth-like ratios |
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Dec 28 2013, 06:17 PM
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#20
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Member Group: Members Posts: 495 Joined: 12-February 12 Member No.: 6336 |
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