Rosetta was a space probe, built by ESA and launched in March 2004. Rosetta, and its lander module Philae, made a detailed study of the comet 67P. During its journey, the spacecraft flew by Mars, and 2 objects in the asteroid belt.
Rosetta was the first spacecraft to:
- orbit a comet
- fly alongside a comet as it traveled towards the inner Solar System
- study a frozen comet being warmed by the Sun
- successfully land on a comet (Philae)
- take photographs from a comet's surface (Philae)
On 6th August 2014, Rosetta reached the comet 67P. The spacecraft entered an orbit of the comet, about 20 km from its surface. On 12th November, Rosetta's lander module Philae completed the first ever successful landing on a comet. However, Philae became wedged into a dark crevice of the comet, and could not generate solar power. After 2 days, its battery power ran out. Communications with Philae ended (until a brief reconnection in July 2015), and were eventually turned off in July 2016.
Philae studied the comet's activities and development over time, and investigated the chemical composition of the comet. Scientific instruments on board the spacecraft detected organic molecules, including amino acids, in the comet's atmosphere. It also discovered oxygen gas surrounding the comet.
As the orbit of the comet took it further from the Sun, Rosetta's solar panels could not generate enough power to keep the spacecraft from freezing. ESA decided to end Rosetta's mission in September 2016. The spacecraft completed a controlled crash-landing onto the comet, taking final data to return to Earth as it approached the surface.