Imagine waiting ten years to see if your hard work paid off, only to have your hopes dashed at the 11th hour. This was the situation faced by European Space Agency (ESA) scientists working on the Rosetta Project; a mission designed to undertake the first ever soft-landing on a comet. Launched in 2004, the Philae lander and Rosetta orbiting satellite spent a decade racing towards the Churyumov–Gerasimenko comet. When the time came to land, Philae touched down at the intended spot, only for its graspers to fail. This caused it to bounce twice for more than a kilometer down the comet, coming to land in a sub-optimal spot.
The final resting place of Philae saw the craft situated in a location with insufficient exposure to the Sun, a factor critical for the solar-powered mission to succeed. While scientists were initially at a loss, they calculated that as Churyumov–Gerasimenko came closer to the Sun, Philae would receive enough sunlight to operate. Uwe Meierhenrich, an analytical chemist working on the project details the trepidation felt by the science team regarding Philae’s fate:
“We all said the chance that the lander would wake up was 50:50, but actually many of us thought it was much less.”
Fortunately, on June 13th at 22:28 CEST the ESA received a signal from Philae. The spacecraft had weathered the extreme cold and lack of power, and reported better than expected conditions. Scientists must first re-align the orbiting Rosetta satellite to ensure uninterrupted communication with Philae. Once this is completed, Philae will be able to start science experiments including, probing the comet’s interior, photographing the surface, and determining the composition of the celestial body.
The trials for the mission are not over yet though, for as the comet approaches the Sun, particles are blasted off by solar radiation and heat. While this provides Philae with more particles to analyze, this detritus poses a risk to Rosetta’s navigation system. Consequently, Rosetta will have to eventually withdraw to a safe distance where it cannot communicate with Philae, although once the comet rounds the Sun in September, Rosetta will be able to return and reinitialize communications with Philae.