On Nov. 12, 2014, 317 million miles (510 million kilometers) from Earth and 14 miles (22.5 km) from comet 67p, the European Space Agency's Rosetta probe releases the Philae lander.
A comet nucleus has very low gravity, so the lander relied on harpoons, hold-down thrusters and ice screws to secure itself to the surface. When these mechanisms all failed, the lander bounced back into space for a 1 hour and 50 minute ballistic flight. Due to Comet 67P's low gravity, Philae weighed about the same as a paper clip. On its first rebound, Philae ascended with a speed of 15 inches (38 centimeters) per second. Escape velocity from the comet is 19.7 inches (50 cm) per second.