Goals: The primary mission of the European Space Agency's Solar and Heliospheric Observatory (SOHO) spacecrast is to study the solar atmosphere, helioseismology and solar wind, but it has also proved very useful for spotting comets.

Accomplishments: SOHO has found more comets than any other spacecraft -- or person -- to date. The mission logged its 2,000th comet discovery in December 2010. SOHO also has observed comet 96P Machholz three times during its regular trip around the sun roughly every six years.