Ten years ago the MOST spacecraft was launched from a remote launch pad in northern Russia. MOST was placed in a Sun-synchronous orbit (which meant the Sun was always visible) Constant sunlight powered MOST as it observed single stars for weeks at a time. It constantly measured the brightness of these stars - once every minute or so.
This information told astronomers a lot about the interiors of these stars light years away. MOST performed better than space telescopes 10 time more expensive. It lasted years longer than expected.