Emily LakdawallaAug 05, 2014

Today's the day Rosetta arrives at a comet!

The latest image from comet Churyumov-Gerasimenko was taken from less than 250 kilometers away. In less than a day, Rosetta will officially arrive, becoming the first spacecraft ever to orbit a comet!

Comet Churyumov-Gerasimenko from Rosetta on August 4, 2014
Comet Churyumov-Gerasimenko from Rosetta on August 4, 2014 Rosetta took this photo of 67P/Churyumov-Gerasimenko from a distance of 234 kilometers on August 4, 2014, two days before entering orbit. The photo has been rotated and cleaned of artifacts, but not resized. ESA / Rosetta / NavCam / Emily Lakdawalla

Here's a lovely composite of all the approach images so far, by Phil Stooke:

Rosetta approach images of comet Churyumov-Gerasimenko
Rosetta approach images of comet Churyumov-Gerasimenko The images in this composite were taken by Rosetta's NavCam and OSIRIS science camera during the spacecraft's approach to the comet in July and August, 2014. The last image, at lower right, was taken on August 4. ESA / Rosetta / NavCam / MPS for OSIRIS Team MPS / UPD / LAM / IAA / SSO / INTA / UPM / DASP / IDA / Phil Stooke

ESA will be livestreaming the arrival beginning at 08:00 UTC August 6 (which is 1 in the morning my time). At 09:00 UTC, Rosetta will fire its thrusters for 6 minutes and 26 seconds. This will not be Rosetta's final burn -- in fact, in order to stay in the neighborhood of the comet, it will be turning and burning once every three or four days, performing a series of 100-kilometer arcs in a sort of triangular path around the comet.

Here is the anticipated timeline of events in Universal Time (UTC) and my local time (PDT):

  • 08:00/01:00: New Norcia tracking station begins tracking Rosetta
  • 08:00/01:00: Livestream begins
  • 09:00/02:00: Rosetta begins 6.5-minute orbit entry maneuver
  • 09:22/02:22: Start of thruster burn confirmed on the ground (one-way light time is 22.5 minutes)
  • 09:29/02:29: End of thruster burn confirmed on the ground
  • 11:00/04:00: Press briefing at the European Space Operations Centre (will be Livestreamed)

This arrival will be the triumph of a 10-year effort for the European Space Agency to match orbits with a comet. They posted a nice long feature on how they track a spacecraft following a comet, with a great photo of their navigation team. I may not be awake at the time of the orbit insertion, but I've asked German blogger Daniel Fischer to report from the media events for us; check his Twitter feed for updates!

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