Comet landing timeline

12 November 2014 Stephen Clark

NOTE: All times in GMT (EST-5hrs; CET+1hr) and Earth Receive Time, when confirmation of the events is received on the ground. Events actually occur approximately 28 minutes, 20 seconds, earlier.

Nov. 12 at 0403 GMT:

Start of Philae's Separation, Descent and Landing activities. This sequence includes heating of the lander batteries to separation temperature and activation of science instruments.
Start of Philae’s Separation, Descent and Landing activities. This sequence includes heating of the lander batteries to separation temperature and activation of science instruments. The lander also turns on its separation motors and transitions to internal battery power in the last 20 minutes before release.

Nov. 12 at 0630 GMT

Rosetta conducts a "pre-delivery" maneuver to put the spacecraft in the correct position to release Philae.
Rosetta conducts a “pre-delivery” maneuver to put the spacecraft in the correct position to release Philae.

Nov. 12 at ~0700 GMT:

The fourth and final Go/No Go decision point comes after confirmation of a satisfactory pre-delivery maneuver by Rosetta.
The fourth and final Go/No Go decision point comes after confirmation of a satisfactory pre-delivery maneuver by Rosetta.

Nov. 12 at 0903 GMT:

Artist's concept of the Philae comet lander ejecting from Rosetta to begin its seven-hour descent. Credit: NASA
Three rotating screws nudge the Philae lander away from Rosetta at a velocity of about 20 centimeters per second, or 0.4 mph.

Nov. 12 from 0904-0947 GMT:

Rosetta_at_Comet_landscape
The Philae lander conducts its post-separation maneuvers, including taking images of the Rosetta orbiter with the CIVA camera payload, deployment of its three landing legs and magnetometer boom, and a 14-degree rotation of the probe’s main body relative to its legs to get into a stable orientation for touchdown.

Nov. 12 at 0943 GMT:

orbits_rosetta
Rosetta performs its post-delivery maneuver to get into position to relay data from Philae back to Earth.

Nov. 12 at 1053 GMT:

Rosetta_and_Philae_at_comet
Philae acquisition of signal from Rosetta. The two spacecraft establish communications and Philae begins downlinking data and images to the ground via Rosetta a few minutes later, including farewell shots it captured of the mothership during separation.

Nov. 12 at 1458-1517 GMT

Philae_touchdown
Philae begins its pre-landing sequence. This phase includes the switch-on of the harpoon anchoring system to be fired at touchdown, preparation of the active descent system — a cold gas thruster used to stabilize the lander at touchdown — and the start of acquisition of images with Philae’s descent camera.

Nov. 12 at 1602 GMT (possible variability)

At the moment of touchdown on comet 67P/Churyumov–Gerasimenko, landing gear will absorb the forces of landing while ice screws in each of the probe’s feet and a harpoon system will lock Philae to the surface. At the same time, a thruster on top of the lander will push it down to counteract the impulse of the harpoon imparted in the opposite direction. Credit: ESA/ATG medialab
At the moment of touchdown on comet 67P/Churyumov–Gerasimenko, landing gear will absorb the forces of landing while ice screws in each of the probe’s feet and a harpoon system will lock Philae to the surface. At the same time, a thruster on top of the lander will push it down to counteract the impulse of the harpoon imparted in the opposite direction.

Nov. 12 at 1607 GMT (possible variability)

The lander begins an automated series of science observations, including panoramic imaging.
The lander begins an automated series of science observations, including panoramic imaging.

 

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News

Researchers race to collect comet data from Philae

13 November 2014 Stephen Clark

DARMSTADT, Germany — Comet scientists planned to send up new orders to Europe’s Philae lander Thursday to kick off a second day of research after the probe endured a jumpy touchdown on comet 67P/Churyumov-Gerasimenko. Time is of the essence because the oven-sized landing craft is facing a power crunch. The lander bounced across the comet’s tortured landscape before coming to rest near a cliff that blocks sunlight from reaching Philae’s solar panels, meaning the craft’s power generation system may be unable to recharge its batteries. Officials said Thursday the Philae might be on its side, with two of its landing legs contacting the comet’s surface and another off the ground. The first images from Philae’s CIVA camera system — made up of seven micro-cameras in a ring around the lander — appeared to show fragments of rock illuminated by the sun on one side of the probe and the sky on the other side. Philae’s landing legs also appear in the images. “We saw both something that man built — the lander — you see the foot there, and something that nature built 4.6 billion years ago, which is a comet essentially preserved as it was at that time, containing all