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Aug 15 2014 01:04am
Tracking topic. I love this stuff
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Aug 15 2014 02:35am
Quote (James84 @ 30 Jul 2014 02:34)
Cool stuff.
So am I to guess that once it gets closer to our Sun (the comet), Rosetta and Philae who are following it, will most likely burn away, explode, malfunction, die? But the info they gather will be sent to Earth.


sorry, forgot to answer your question till now
but no, hopefully nothing will "burn away, malfunction, die"
the link in post#16 shows the flight path and while some stuff from the comet will evaporate
it will return to realms further away from the sun with the probe following (not sure how far)
the mission is timed so that the probe gets enough solar power
and will end when the probe's solar panels don't provide enough power anymore

another worthwhile article: http://www.newscientist.com/article/mg22329822.400-rosetta-probe-poised-to-touch-and-taste-a-comet.html?page=1#.U-3FHqNht8E
the most interesting points:

22-24 August European Space Agency will use data from Rosetta to choose up to five possible landing sites on the comet
13-14 September ESA will select a primary and backup landing site
...
Green marks the spot




Comet 67P's bulbous shape, which has been likened to a rubber duck, means only a few spots are suitable for landing. Those highlighted in green are probably safe places for a lander to touch down. The other colours mark where sunlight falls – blue for always dark, red for always light, and the rest in between.

This post was edited by brmv on Aug 15 2014 02:40am
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Aug 15 2014 09:32am
makes me want to play kerbal space program
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Aug 16 2014 06:36am
another sketch of the flight path indicating temperature zones and coma development (take note 'James84') in

http://rosetta.jpl.nasa.gov/sites/default/files/rosetta_info/index.html
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Aug 16 2014 04:57pm
Ty, I havn't posted but been checking out the links, etc. :)

Took me a while to get to read the "real hot" zone, lol. Was so small, couldn't make it any big.
I see Rosetta is moving along to hide and so forth from the heat, although I wonder again, how hot is it?
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Aug 16 2014 05:23pm
Quote (James84 @ 16 Aug 2014 22:57)
... although I wonder again, how hot is it?


we'll know for sure (*) when the comet and the probe pass through those zones, VIRTIS will tell us, from ESA:

VIRTIS (Visible and Infrared Thermal Imaging Spectrometer) maps and studies the nature of the solids and the temperature on the surface of the nucleus. Also identifies comet gases, characterises the physical conditions of the coma and helps to identify the best landing sites.
Principal Investigator: Fabrizio Capaccioni, Istituto di Astrofisica e Planetologia Spaziali, Rome, Italy.


there is also the following BBC article with new information including several pictures -> http://www.bbc.com/news/science-environment-28741244
apart from the images the most interesting part is:

The Grain Impact Analyser and Dust Accumulator (Giada), has reported detecting its first dust grains - just four, but it will not be long before it is being peppered by material coming off the comet.
67P is relatively quiet at the moment, moving some 530 million km from the Sun. As it gets closer to our star in the coming months, its ices will warm and copious amounts of gas and dusty particles will be ejected.


&

... the roughly 4km-wide comet as it turns on its axis - a rotation that takes 12.4 hours.

/edit

(*) with the temperature on the moon ranging up to '253 Fahrenheit (123 Celsius)' it should be a little lower on the comet since it stays outside of the orbit of earth
but it will also depend on how much heat can be trapped by material on the comets surface so could even be higher (just a rough indicator)

This post was edited by brmv on Aug 16 2014 05:38pm
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Aug 16 2014 07:58pm
Quote (brmv @ Aug 16 2014 07:23pm)
we'll know for sure (*) when the comet and the probe pass through those zones, VIRTIS will tell us, from ESA:

VIRTIS (Visible and Infrared Thermal Imaging Spectrometer) maps and studies the nature of the solids and the temperature on the surface of the nucleus. Also identifies comet gases, characterises the physical conditions of the coma and helps to identify the best landing sites.
Principal Investigator: Fabrizio Capaccioni, Istituto di Astrofisica e Planetologia Spaziali, Rome, Italy.


there is also the following BBC article with new information including several pictures -> http://www.bbc.com/news/science-environment-28741244
apart from the images the most interesting part is:

The Grain Impact Analyser and Dust Accumulator (Giada), has reported detecting its first dust grains - just four, but it will not be long before it is being peppered by material coming off the comet.
67P is relatively quiet at the moment, moving some 530 million km from the Sun. As it gets closer to our star in the coming months, its ices will warm and copious amounts of gas and dusty particles will be ejected.


&

... the roughly 4km-wide comet as it turns on its axis - a rotation that takes 12.4 hours.

/edit

(*) with the temperature on the moon ranging up to '253 Fahrenheit (123 Celsius)' it should be a little lower on the comet since it stays outside of the orbit of earth
but it will also depend on how much heat can be trapped by material on the comets surface so could even be higher (just a rough indicator)


Good stuff.
I was wrong, I kept thinking it was going to be much much hotter, closer to the 1k + Celsius, instead of only a couple to a few hundred.
But tis true, depending on components on mats on the comet, they could be higher.

This post was edited by James84 on Aug 16 2014 07:59pm
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Aug 17 2014 02:20am
Quote (James84 @ 17 Aug 2014 01:58)
Good stuff.
I was wrong, I kept thinking it was going to be much much hotter, closer to the 1k + Celsius, instead of only a couple to a few hundred.
But tis true, depending on components on mats on the comet, they could be higher.


even on venus with the thick cloud layer the temperature stays below half of that with an average temperature around 460C
and the comet which has no atmosphere would have to venture noticeably closer than mercury (which has a maximum temperature of 430C) to reach 1kC
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Aug 17 2014 07:27pm
@ 'James84', some more comments on temperature:

from http://www.armaghplanet.com/blog/ison-things-you-need-to-know.html

Comet ISON will make its closest approach to the Sun, or perihelion, on 28 November 2013 at a distance of only 1.2 million km (about 750 000 miles) from the surface of the Sun. This orbit will actually take the comet through the Sun’s outer atmosphere and the comet’s surface temperature may exceed that of molten iron (1538 °C).

that indicates how close has a comet to get to the sun to reach a surface temperature of over 1000C
but the temperature in the tail is a totally different matter as can be seen in the following article http://www.agu.org/books/sp/v027/SP027p0242/SP027p0242.pdf
and also a general article http://earthsci.org/fossils/space/comets/comet.html
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Aug 19 2014 09:01am
slowly slowly the probe is getting closer to the comet, now on the second triangular leg

The mission team are now planning the next CAT burns, CAT 4, 5 and 6, on 20, 24 and 27 August, respectively.
"The mission team are working intensively, and we've transitioned onto a new weekly planning cycle to cater for the CAT burns that happen every Wednesday and Sunday in August," says Jose-Luis Pellon-Bailon, acting Spacecraft Operations Manager.
To give an idea of the incredible precision of the flight dynamics work being done to support these intricate manoeuvres, note that the orbit determination done after the 13 August burn found that Rosetta’s thrusters had over-performed by about 0.2% – a tiny amount in the order of an astonishing +2 mm/second!


and the latest image, now from ~84km:

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