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.
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.
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.
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.
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:
Recent Images from the Rosetta Mission
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)