Home > Comet, Ephemeris Program, ESA > 11/18/2014 – Ephemeris – Rosetta, Philae with Comet 67P and Maven’s discovery of the effects of it’s comet encounter

11/18/2014 – Ephemeris – Rosetta, Philae with Comet 67P and Maven’s discovery of the effects of it’s comet encounter

November 18, 2014

Ephemeris for Tuesday, November 18th.  The sun will rise at 7:43.  It’ll be up for 9 hours and 28 minutes, setting at 5:11.   The moon, half way from last quarter to new, will rise at 4:31 tomorrow morning.

Last week the Philae lander bounced down on Comet 67P/Churyumov-Gerasimenko, its harpoons not able to fire to hold the lander down.  “Where is Captain Ahab when you need him?” I Twittered at the time.  We were lucky it didn’t bounce off the comet entirely.  It ended against a cliff and in a shadow, so it couldn’t recharge its batteries from sunlight. The ESA controllers had it perform all its possible experiments quickly before its batteries died.  Philae was still an amazing success.  News from last month’s encounter Mars encounter with Comet Siding Spring. The Maven satellite detected the aftermath of a great martian meteor shower when it peaked around the planet from where it was hiding.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.



If I’m understanding the spacecraft controllers at the European Space Agency (ESA) correctly Philae was launched toward the comet with a velocity of something like .7 meters per second (m/s).  It would have accelerated to 1 m/s by the time it hit the comet.  So it was pushed into the comet at more than the comet’s escape velocity.  One meter per second is only 2.2 miles per hour.  So to bounce and not escape the comet either the lander, the surface of the comet or both would have to have a lot of give to it.  On this comet one could jump faster than escape velocity and go floating off into space.

Philae bounce

The Rosetta spacecraft spotted Philae and its shadow shortly after the lander touched down on Comet 67P/Churyumov–Gerasimenko and bounced up again. The first image is taken on Nov. 12, 2014 at 10:30 a.m. EDT (3:30 p.m. UTC) and the second five minutes later. Credit: ESA/Rosetta/NAVCAM; pre-processed by Mikel Catania. Hat tip to and credit for the caption to Universe Today.


Maven detected the aftermath of a meteor storm in the upper martian atmosphere with the signatures of eight metals.  It looks like it was prudent to hide all the satellites when Mars came closest to the comet’s path.  Here’s a link to Bob King’s post about it in Universe Today blog from 11 days ago.

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