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Philae, we hardly knew ye


Artist’s depiction of the Rosetta spacecraft’s Philae lander on Comet 67P Churyumov–Gerasimenko. Image Credit: European Space Agency

The European Space Agency (ESA) has suspended further attempts to contact Philae, the small comet lander currently sitting on Comet 67P/Churyumov–Gerasimenko (67P). The lander has not been heard from since July of 2015, and that signal was intermittent at best.

Philae was part of the Rosetta mission – a combined lander and orbiter designed for cometary exploration. The ESA-launched Rosetta on March 2, 2004, with the spacecraft taking more than 10 years to reach its destination. After orbiting the comet for a few weeks, Philae detached from Rosetta and began the much shorter trip to the comet’s surface.

The Ariane 5 booster with Rosetta and the Philae lander lifts off from the Spaceport at Kourou, French Guiana on March 2, 2004. Photo Credit: ESA

The Ariane 5 booster with Rosetta and the Philae lander lifts off from the Spaceport at Kourou, French Guiana, on March 2, 2004. Photo Credit: ESA

The small lander arrived at the comet on Nov. 12, 2014. Upon its approach to the dirty snowball, a set of harpoon-like spikes were deployed to help anchor the spacecraft to comet 67P’s surface.

Things did not go exactly as ESA had planned, however. The landing site was not made of the soft material engineers were expecting. Instead. the finely granulated surface hid a large deposit of hard water ice. Instead of latching onto the comet, Philae bounced away.

After bouncing from its original landing location, Philae came to rest in the shadow of an outcropping, depriving the spacecraft of solar power. Relying on just its primary battery, Philae transmitted for more than 60 hours before going silent.

The outcropping prevented Philae from using solar power to charge the second battery. It was hoped that as Comet 67P approached the Sun, the solar panels would collect enough power so that contact could be re-established. ESA continued its attempts to talk to the lander, but other than the sporadic transmissions July, the craft has remained silent.

Philae was sent to study Comet 67P’s elemental, isotopic, molecular, and mineralogical composition in an effort to understand cometary structure. It that regard, the lander also characterized the physical properties of the comet including subsurface as well as surface materials.

Rosetta, meanwhile, continued to study Comet 67P collecting information on the chemical composition of the comet. Rosetta reported back on the comet’s atmospheric development as 67P approached and then withdrew from the Sun.

As the comet reached perihelion, Rosetta moved away from the comet to avoid any potential damage from cometary debris. Once Comet 67P began the long trek back to the outer reaches of the Solar System, the orbiter dropped its altitude and searched for a signal from Philae – but it never regained contact. Rosetta continues to transmit scientific data about the comet as it drifts farther away from the Sun.

“The chances for Philae to contact our team at our lander control center are unfortunately getting close to zero,” said Stephan Ulamec, Philae project manager at the German Aerospace Center, DLR. “We are not sending commands [anymore] and it would be very surprising if we were to receive a signal again.”

Philae will now traverse the Solar System in silence, a high-tech relic left on the surface of comet 67P. Its legacy, that of the first spacecraft to safely touch down on the surface of a comet, is secure.

Video courtesy of ESA


Joe Latrell is a life-long avid space enthusiast having created his own rocket company in Roswell, NM in addition to other consumer space endeavors. He continues to design, build and launch his own rockets and has a passion to see the next generation excited about the opportunities of space exploration. Joe lends his experiences from the corporate and small business arenas to organizations such as Teachers In Space, Inc. He is also actively engaged in his church investing his many skills to assist this and other non-profit endeavors.

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