/Churyumov-Gerasimenko is known as a short-period comet . Rosetta will be the first spacecraft to orbit a comet and to place a lander on the surface . ESA says the mission objective is to help understand the evolution of the solar system . Comment: Some believe Earth may have received its water from comets .
Rosetta will be the first spacecraft to orbit a comet and to place a lander on the surface . ESA says the mission objective is to help understand the evolution of the solar system . Comment: Some believe Earth may have received its water from comets .