Philae Phones Home

The European Space Agency’s (ESA’s) Philae comet lander has awakened and is sending data back to Earth once more.  Scientists have anxiously waited seven months for this moment.

Philae (pronounced fee-LAY) landed on Comet 67P/Churyumov-Gerasimenko on November 12, 2014 Eastern Standard Time (EST) — three times, in fact, as it bounced off the surface and finally settled in an area shaded from the Sun.   Because the Sun could not recharge its batteries, the lander fell silent after its initial round of experiments using its 10 scientific instruments. 

Philae journeyed to Comet 67P attached to the Rosetta orbiter, which continues to orbit the comet as it comes closer and closer to the Sun.   Philae communicates with Earth via Rosetta.

Rosetta is the first spacecraft to orbit a comet and Philae is the first to land on one.  Comet 67P was about 510 million kilometers from Earth when the landing took place.  It took the spacecraft 10 years to reach the comet after traveling a circuitous 6.5 billion-kilometer route.

Philae wakes up.  Image credit:  European Space Agency tweet @esa June 14, 2015

Stephan Ulamec of the German space agency DLR and Philae’s project manager said the lander is doing well and is “ready for operations.”  He reported that it has 24 watts of power available, indicating that its solar panels are recharging the spacecraft’s batteries.  Signals were received at ESA’s European Space Operations Centre in Darmstaad, Germany on June 13 at 22:28 Central European Summer Time (CEST) for 85 seconds.

The solar panels were in shadow in November after Philae finally stopped bouncing and landed for the third time.   The project’s scientists and engineers hoped that as the comet changed its position relative to the Sun that the solar panels might be illuminated sufficiently to recharge the batteries.  Their wish came true.

ESA describes the purpose of the mission as to “unlock the mysteries of
the oldest building blocks of our solar system — comets” and therefore the names are associated with deciphering hieroglyphics.  Rosetta is named after the Rosetta Stone that allowed the deciphering of hieroglyphics and therefore an understanding of the Egyptian civilization.  Philae is the name of an island in the Nile River where an obelisk was found with the final clues to enable the decryption.

The comet is named after the two Kiev, Ukraine astronomers who discovered it in 1969, Klim Churyumov and Svetlana Gerasimenko, while conducting comet observations at the Alma-Ata Astrophysical Institute in Kazakhstan.