WMAP

One of the more famous scientific probes, WMAP operated from 2001 to 2010 making all-sky surveys of the cosmic microwave background, the radiation left over from the recombination epoch which occurred roughly 380,000 years after the Big Bang. WMAP flew Lissajous orbits around L2, a Lagrange point chosen to minimize the amount of solar and terrestrial contamination with the sensors. Even still, WMAP had to use a sunshield which also added a convenient place to put the probe's solar arrays.