Contact with Philae Reestablished

Update: Nov 17, 2014: Philae lander’s battery power has dropped too low to safely maintain operations, and the lander is now in standby mode. ESA reports that the lander may be in standby mode for quite some time: http://blogs.esa.int/rosetta/2014/11/15/our-landers-asleep/

Update: 13:40 GMT, Nov 13, 2014: In ESA’s media brief, the mission team explained that, after bouncing, the Philae lander may be  positioned in a permanent shadow on the comet 67P/Churyumov–Gerasimenko. This could affect the amount of sunlight that reaches the lander, potentially limiting the energy produced by its solar panels. As of now, there’s no telling how long Philae will last. Rosetta itself has another 20 months of exploring the comet in its primary mission.

A tweet from the Philae Lander on Twitter. Credit: ESA, twitter.com/philae2014

A tweet from the Philae Lander on Twitter. Credit: ESA, twitter.com/philae2014

This image from the ESA press briefing shows the nominal landing site in red. Philae then bounced and is located somewhere within the blue diamond. Credit: ESA

This image from the ESA press briefing shows the nominal landing site in red. Philae then bounced and is located somewhere within the blue diamond. Credit: ESA


 

Rosetta’s lander Philae is safely on the surface of Comet 67P/Churyumov-Gerasimenko, as these first two CIVA images confirm. One of the lander’s three feet can be seen in the foreground. The image is a two-image mosaic. The full panoramic from CIVA will be delivered in this afternoon’s press briefing at 13:00 GMT/14:00 CET. Credit: ESA/Rosetta/Philae/CIVA

Rosetta’s lander Philae is safely on the surface of Comet 67P/Churyumov-Gerasimenko, as these first two CIVA images confirm. One of the lander’s three feet can be seen in the foreground. The image is a two-image mosaic. The full panoramic from CIVA will be delivered in this afternoon’s press briefing at 13:00 GMT/14:00 CET. Credit: ESA/Rosetta/Philae/CIVA

Yesterday, the European Space Agency’s (ESA) Rosetta mission performed the first soft landing on a comet. The landing didn’t go entirely according to plan, but contact has been reestablished and the Philae lander appears to be safely on the comet.

Bouncing Down to a Comet

When Philae touched down on the comet 67P/Churyumov–Gerasimenko, it was supposed to fire anchoring harpoons that would keep it safely attached to the comet’s surface. However, the harpoons did not fire. Instead of being safely anchored, the lander relied on the comet’s low gravity to stay in position.

The image shows comet 67P/CG acquired by the ROLIS instrument on the Philae lander during descent on Nov 12, 2014 14:38:41 UT from a distance of approximately 3 km from the surface. The landing site is imaged with a resolution of about 3m per pixel. Credit: ESA/Rosetta/Philae/ROLIS/DLR

The image shows comet 67P/CG acquired by the ROLIS instrument on the Philae lander during descent on Nov 12, 2014 14:38:41 UT from a distance of approximately 3 km from the surface. The landing site is imaged with a resolution of about 3m per pixel. Credit: ESA/Rosetta/Philae/ROLIS/DLR

During ESA’s live coverage of events, Dr. Stephan Ulamec, Head Rosetta Lander at the German Aerospace Center (DLR), suggested that Philae had “landed twice,” and may have bounced up and turned slightly after first contact with the comet.

The sequence of events during the landing was a bit harrowing for all who were watching, and it now appears that the craft bounced twice. Philae made it to the surface of the comet and sunk about four centimeters into soft dust and debris. But then the small craft bounced off as its harpoons failed to fire.

Gravity on 67P/Churyumov–Gerasimenko has been estimated (based on simulations) to be only one ten-thousandth of what we experience here on Earth.

This low gravity meant that Philae’s first bounce after landing took it about a kilometer from the surface before falling back down toward the comet two hours later. When it hit the comet a second time, Philae bounced again – but this time it only lifted a short way and fell back to the comet after 10 minutes.

Now, it appears that Philae is safely in position.

In Position for Science

Philae is currently sending a steady signal, and data is pouring back to Earth. Using its Comet nucleus Infrared and Visible Analyzer (CIVA), Philae has sent back images to confirm that it is safely at the comet’s surface.

Before the lander begins its primary mission, the mission team will work to determine exactly where Philae has come to rest on the comet.

Rosetta’s OSIRIS narrow-angle camera captured this parting shot of the Philae lander after separation. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Rosetta’s OSIRIS narrow-angle camera captured this parting shot of the Philae lander after separation. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

The Philae lander was released from the Rosetta spacecraft after a nearly decade-long journey through space. The small craft spent seven hours descending toward the surface of Comet 67P/Churyumov–Gerasimenko. At 16:03 GMT, a signal was received that Philae had become the first robotic mission to perform a soft landing on a comet.

When Philae bounced up from the comet, the comet continued turning while the lander was ‘airborne’ for two hours. When the lander finally came to rest, it ended up in a position slightly different than the intended landing site.

Philae‘s original landing site was carefully selected for scientific value, and also for optimum exposure to the sunlight that will keep the lander charged.

It is now important to determine the lander’s exact location so that the mission team can determine how effectively its solar panels can power the spacecraft, and the nature of the surface where the probe will be drilling.

RosettaTweet

ESA Rosetta Mission on Twitter. Credit: ESA

The Rosetta mission will return valuable data about Comet 67P/Churyumov–Gerasimenko that will help astrobiologists understand the formation of our solar system and the potential role of comets in delivering materials for the origin of life on the early Earth.

For more details about the mission and its goals:

Living on the Edge: Rosetta’s Lander Philae Is Set to Take the Plunge

To Catch a Comet by the Tail: Rosetta’s Historic Meet and Greet with Churyumov-Gerasimenko

Recent Images from the Rosetta Mission

The first panoramic ‘postcard’ from the surface of a comet returned by Rosetta’s lander Philae. Credit: ESA

The first panoramic ‘postcard’ from the surface of a comet returned by Rosetta’s lander Philae. Credit: ESA

The signal confirming landing arrived on Earth at 16:03 GMT (17:03 CET). Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Rosetta’s OSIRIS narrow-angle camera witnessed Philae’s descent to the surface of Comet 67P/Churyumov-Gerasimenko yesterday. This animated gif comprises images captured between 10:24 and 14:24 GMT (onboard spacecraft time). More images showing Philae closer to the surface are still to be downloaded. Separation occurred onboard the spacecraft at 08:35 GMT (09:35 CET), with the confirmation signal arriving on Earth at 09:03 GMT (10:03 CET). The signal confirming landing arrived on Earth at 16:03 GMT (17:03 CET). Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Rosetta’s lander Philae took this parting shot of its mothership shortly after separation. The image was taken with the lander’s CIVA-P imaging system and captures  one of Rosetta's 14 metre-long solar arrays. It was stored onboard the lander until the radio link was established with Rosetta around two hours after separation, and then relayed to Earth. The lander separated from the orbiter at 09:03 GMT/10:03 CET and is expected to touch down on Comet 67P/Churyumov–Gerasimenko seven hours later. Confirmation of a successful touchdown is expected in a one-hour window centred on 16:02 GMT / 17:02 CET.  Rosetta and Philae had been riding through space together for more than 10 years. While Philae is set to become the first probe to land on a comet, Rosetta is already the first to rendezvous with a comet and follow it around the Sun. The information collected by Philae at one location on the surface will complement that collected by the Rosetta orbiter for the entire comet. Credit: ESA/Rosetta/Philae/CIVA

Rosetta’s lander Philae took this parting shot of its mothership shortly after separation. The image was taken with the lander’s CIVA-P imaging system and captures one of Rosetta’s 14 metre-long solar arrays. It was stored onboard the lander until the radio link was established with Rosetta around two hours after separation, and then relayed to Earth.
The lander separated from the orbiter at 09:03 GMT/10:03 CET and is expected to touch down on Comet 67P/Churyumov–Gerasimenko seven hours later. Confirmation of a successful touchdown is expected in a one-hour window centred on 16:02 GMT / 17:02 CET.
Rosetta and Philae had been riding through space together for more than 10 years. While Philae is set to become the first probe to land on a comet, Rosetta is already the first to rendezvous with a comet and follow it around the Sun. The information collected by Philae at one location on the surface will complement that collected by the Rosetta orbiter for the entire comet. Credit: ESA/Rosetta/Philae/CIVA

A rare glance at the dark side of comet 67P/Churyumov-Gerasimenko. Light backscattered from dust particles in the comet’s coma reveals a hint of surface structures. This image was taken by OSIRIS, Rosetta’s scientific imaging system, on September 29th, 2014 from a distance of approximately 19 kilometers.   [less] ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

A rare glance at the dark side of comet 67P/Churyumov-Gerasimenko. Light backscattered from dust particles in the comet’s coma reveals a hint of surface structures. This image was taken by OSIRIS, Rosetta’s scientific imaging system, on September 29th, 2014 from a distance of approximately 19 kilometers. Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

An image without the landing site marked is available here. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA

Close-up of the region containing Philae’s primary landing site J, which is located on the ‘head’ of Comet 67P/Churyumov–Gerasimenko. The mosaic comprises two images taken by Rosetta’s OSIRIS narrow-angle camera on 14 September 2014 from a distance of about 30 km. The image scale is 0.5 m/pixel. The circle is centred on the landing site and is approximately 500 m in radius.
An image without the landing site marked is available here. Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA


After a ten-year journey, Rosetta and Philae had finally reached their destination, Comet 67P/Churyumov–Gerasimenko. Rosetta spent many weeks studying the comet, sending lots of information back to Earth. But where was Philae going to land?Credit: European Space Agency, ESA (YouTube)