For the first time ever, a spacecraft has landed on a comet. The European Space Agency’s Philae, the size of a washing machine, decended from the mother ship Rosetta to Comet 67P on Wednesday. Overnight, commands were sent to wake up Philae, but the robotic lander began using a backup computer rather than the main computer. The result was that not all the telemetry data was being sent to Earth. The agency solved the problem by “power-cycling” the lander. Philae has spent 10 years fixed to the side of Rosetta during the journey across the solar system. Scientists hope the probe will help them learn a lot more about the composition of comets and how they react when they get close to the sun.