While the world waited breathlessly for the first photos to arrive from New Horizons’ July 14 encounter with Pluto and its moons, the European Space Agency’s (ESA) Rosetta spacecraft has continued sending images and data concerning Comet 67P/Churyumov-Gerasimenko back to its home planet during its recently extended scientific mission. Rosetta’s team currently is gearing up for perihelion, when the comet will make its closest approach to the Sun. In addition, the Philae lander, which famously “woke up” last month following a seven-month hibernation upon the comet’s surface, last communicated with Earth on July 9. Sadly, the Rosetta team also had to say goodbye to one of its own last week, as Dr. Claudia Alexander, project scientist/project manager of the Rosetta’s U.S. portion, passed away following a fight with breast cancer.
Rosetta Team Gets Ready for Perihelion
Rosetta’s team is counting down for perihelion, which will occur Aug. 13, over a year since the orbiter first arrived at Comet 67P/Churyumov-Gerasimenko on Aug. 6, 2014. During perihelion, activity is expected to be high, as the comet will be approximately 186 million kilometers (approximately 115 million miles) from the Sun. As a comet is warmed up by the Sun, its ice is warmed and it generates vapor; this vapor manifests itself in the form of a “coma,” or a visible tail. Rosetta is in the perfect position to observe how the comet’s activity changes as it grows closer and closer to our nearest star.
Rosetta’s project scientist Matt Taylor discussed the importance of observing the comet as is approaches—and reaches—perihelion: “Perihelion is an important milestone in any comet’s calendar, and even more so for the Rosetta mission because this will be the first time a spacecraft has been following a comet from close quarters as it moves through this phase of its journey around the Solar System. We’re looking forward to reaching perihelion, after which we’ll be continuing to monitor how the comet’s nucleus, activity and plasma environment changes in the year after, as part of our long-term studies.”
Philae Lander Communicates, Albeit Briefly, With Rosetta Again
Philae, the lucky lander that survived not one, but three landings on the comet, and a hibernation period lasting seven months on its surface, communicated through the Rosetta orbiter for 12 minutes on July 9. In addition, the lander relayed data from its COmet Nucleus Sounding Experiment by Radiowave Transmission (CONSERT) instrument. CONSERT had been powered up on July 5; it appears the instrument was activated by the lander on July 9. This gives ground controllers hope that Philae still may be usable after its long “sleep.” Philae had remained quiet since its last communication on June 24.
ESA underscored why communications with Philae may be so sporadic: “ … Philae has to communicate with the ground stations through Rosetta, which acts as a radio relay. Restrictions on the orbiter’s approach to and orbit around the comet have not permitted regular communication with the lander. The data sent on 24 June did not suggest that the lander had experienced technical difficulties. Now, Philae’s internal temperature of zero degrees Celsius [32 degrees Fahrenheit] gives the team hope that the lander can charge its batteries; this would make scientific work possible regardless of the ‘time of day’ on the comet.”
It has also been theorized in a short video released by DLR, the German Aerospace Center, that “there is a suspicion that the transmitters are not working as expected,” and ground controllers have prepared a software patch to try to improve communications. This patch has been uploaded to Rosetta, and will be sent to Philae as soon as possible. Communications with Philae are monitored by DLR Lander Control Center in Cologne, Germany.
The Rosetta Team and Colleagues Remember Dr. Claudia Alexander (1959 – 2015)
“When [science] permits us to see the far side of a new horizon, we remember those who paved the way, seeing for them also.” – Carl Sagan
While we watch the achievements made by our world’s robotic space explorers in awe (especially during this last week), it’s easy to forget that there is a very human side to these explorers: the scientists and controllers who give life to these projects on Earth. Sadly, on July 11, the Rosetta team lost one of these scientists, Dr. Claudia Alexander, who passed away after a 10-year battle with breast cancer.
Dr. Alexander was Rosetta’s U.S. project scientist/project manager, and worked at NASA’s Jet Propulsion Laboratory. A trailblazer in her field, she also worked on two other groundbreaking planetary science missions, Galileo and Cassini. She was also a prolific writer with her own publishing imprint, Red Phoenix Books. She was remembered warmly by her friends and colleagues this week as someone who was tirelessly enthusiastic about the little comet that captured the world’s imagination:
“The passing of Claudia Alexander reminds us of how fragile we are as humans, but also as scientists, how lucky we are to be part of planetary science. She and I constantly talked about comets. Comet Churyumov-Gerasimenko in particular. She was an absolute delight to be with, and always had a huge engaging smile when I saw her. It was easy to see that she loved what she was doing. We lost a fantastic colleague and great friend. I will miss her.” — Dr. James Green, Director of NASA’s Planetary Science Division
“We have lost a great colleague and friend who will live on within us and the missions to the stars she made possible.” — Matt Taylor
While her life may have been cut cruelly short and the loss to planetary science is inestimable, Dr. Alexander’s legacy will be felt forever in her field and will continue to inspire young women and students passionate about the sciences. We at AmericaSpace offer our sincerest condolences to her family, friends, and colleagues.
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