First probe to land on a comet powers down

The European Space Agency made history last Wednesday when Philae, named after an island in the Nile, became the first space probe to land on a comet. Philae’s landing took place 311 million miles from Earth; its exact position on the comet, however, is unknown. Launched on March 2, 2004, the probe’s mission is to take pictures of the comet’s surface, determine the comet’s composition, and analyze the comet’s magnetic environment. The comet is comprised of compounds frozen in time from the formation of the solar system. Philae’s mother ship, the Rosetta spacecraft, will examine the comet from a distance as it heads deeper into the solar system.

Landing on a consists of many complicated parts. In Philae’s case, the target comet was irregularly shaped and only 2.5 miles in diameter. ESA experts report that Philae landed more than once as further analysis indicated that the lander bounced on the surface. The bounce has been attributed to a malfunction in Philae’s anchoring harpoons and the comet’s weak gravity. Fortunately, the probe hasn’t sustained any significant damage from the bouncing. Furthermore, images taken by Philae show it pressed up against a slope which reduces the amount of sunlight received by the probe’s solar panels. It was predicted that the probe would receive around seven hours of sunlight per day. Now, however, Philae only gets one and a half hours of sunlight per 12-hour comet day. As a result, Philae is unable to charge its batteries enough to support sustained scientific operations, after having transmitted a plethora of data and images back to Earth and drilling into the comet’s surface, Philae has been put into standby mode by ESA controllers after the probe’s batteries fell dangerously low. Philae was intended to transmit data for nine months, collecting energy as the comet approaches the sun.

Despite its glitches, Philae has completed nearly all of its intended missions. ESA experts hope that by maneuvering the probe more sunlight will reach its solar panels. Additionally, the ESA is hoping to reestablish communication with Philae as it receives more intense solar illumination as its comet comes closer to the sun by August 2015.