Dust particles from Comet 67P/Churyumov-Gerasimenko collected by ESA’s Rosetta spacecraft. Copyright ESA/Rosetta/MPS for COSIMA Team MPS/CSNSM/UNIBW/TUORLA/IWF/IAS/ESA/ BUW/MPE/LPC2E/LCM/FMI/UTU/LISA/UOFC/vH&S
One of the instruments on board ESA’s Rosetta called COSIMA, short for the COmetary Secondary Ion Mass Analyser one of three dust analysis experiments.
Essentially this instrument has a plate for catching dust grains from the comet at fairly low speeds. The dust grains shown above is two of the grains collected and they have yielded some interesting results.
I’ll let ESA explain:
Two examples of dust grains collected by Rosetta’s COmetary Secondary Ion Mass Analyser (COSIMA) instrument in the period 25–31 October 2014. Both grains were collected at a distance of 10–20 km from the comet nucleus. Image (a) shows a dust particle (named by the COSIMA team as Eloi) that crumbled into a rubble pile when collected; (b) shows a dust particle that shattered (named Arvid).
For both grains, the image is shown twice under two different grazing illumination conditions: the top image is illuminated from the right, the bottom image from the left. The brightness is adjusted to emphasise the shadows, in order to determine the height of the dust grain. Eloi therefore reaches about 0.1 mm above the target plate; Arvid about 0.06 mm. The two small grains at the far right of image (b) are not part of the shattered cluster.
The fact that the grains broke apart so easily means their individual parts are not well glued together. If they contained ice they would not shatter; instead, the icy component would evaporate off the grain shortly after touching the collecting plate, leaving voids in what remained. By comparison, if a pure water-ice grain had struck the detector, then only a dark patch would have been seen.
These ‘fluffy’ grains are thought to originate from the dusty layer built up on the comet’s surface since its last close approach to the Sun, and will soon be lost into the coma.
Be sure to check the Rosetta Blog. The have this and results from six other Rosetta’s science instruments since arriving at Comet 67P/Churyumov-Gerasimenko – great stuff!!
Artists concept of Venus Express aerobraking. Credit: ESA
Word comes from ESA the Venus Express mission has come to an end:
ESA’s Venus Express has ended its eight-year mission after far exceeding its planned life. The spacecraft exhausted its propellant during a series of thruster burns to raise its orbit following the low-altitude aerobraking earlier this year.
Since its arrival at Venus in 2006, Venus Express had been on an elliptical 24‑hour orbit, traveling 66 000 km above the south pole at its furthest point and to within 200 km over the north pole on its closest approach, conducting a detailed study of the planet and its atmosphere.
However, after eight years in orbit and with propellant for its propulsion system running low, Venus Express was tasked in mid-2014 with a daring aerobraking campaign, during which it dipped progressively lower into the atmosphere on its closest approaches to the planet.
Read the rest at ESA.
Decline in battery power aboard Philae. Credit: ESA via Twitter
The Philae lander is now in an “idle mode” in which most of the systems on board are shut down, including communications.
Before going to sleep, Philae was able to send all of the science data collected so far and completed its main mission in the 57 hours on the comet surface.
Stephan Ulamec, Lander Manager said “This machine performed magnificently under tough conditions, and we can be fully proud of the incredible scientific success Philae has delivered.”
Contact with Philae was lost at 00:36 UT (20:36 EST for the US), according to Rosetta Blog this was about the time of a scheduled loss of signal anyway as Rosetta which was acting as a repeater orbited out of sight of Philae.
Rosetta mission control did try to rotate the lander as was reported and with that effort there was a possibility of communications at 10:00 UTC (05:00 EST) this morning (15 Nov) so Rosetta was listening but no signal came.
As Comet 67P/Churyumov-Gerasimenko gets closer to the Sun there is a possibility enough sunlight will eventually revive the batteries enough to get Philae back on-line. Still I have to wonder if the deep discharge state of the batteries will preclude that given the time and cold environment – time will tell.
Philae is right at home. Credits: ESA/Rosetta/Philae/CIVA
WOW! This is just simply amazing.
This is a two image mosaic of Philae on the surface of the Comet 67P/Churyumov-Gerasimenko. Click the image and just marvel at the view of both Philae and the surface features.
You can get an even larger version at Rosetta blog’s Welcome to a Comet!
Philae is pretty close to a cliff that will shadow the solar panels for much of a day and this will limit how much Philae will be able to do at least in the short term. I’m pretty sure ESA is studying how to squeeze the most out of what they have you can be sure of that.
ESA is live streaming the media briefings, you can find out when by going to Rosetta Blog or you can check the Live Stream page.
Don’t forget about Twitter, I am on the run a lot the past couple days and it has been great for keeping up you can get all the images and briefings there too.
GOOD LUCK! I can hardly believe the day has finally come – it’s been a long time!
Update: Landing confirmed. Harpoons did not fire, investigation in progress. The one way radio travel time is a bit over 28 minutes – each way.
ESA is reporting all is well with Philae is in good shape despite the harpoons.
If you see no video above it is because ESA isn’t broadcasting at the time.
Check out the Rosetta Blog and for last second updates.