Hubble Space Telescope.

The Hubble Space Telescope (named after the famous astronomer, Edwin Hubble) is a telescope that orbits Earth at an orbital velocity of 7, 500 m/s with an orbit height of 559 km. It was carried into orbit on April 24th, 1990, by Space Shuttle Discovery. This telescope, which was built by NASA and the European Space Agency, is controlled by the Space Telescope Science Institute. Though Hubble cost $36 million, it has sent back thousands of images that have helped explain to us many mystery's of astronomy.

Hubble moves 5 miles per second when orbiting Earth, resulting in a 97 minute orbit period. It is a Cassegrain Reflector: A telescope that uses the light hitting its several mirrors to focus that light into a hole with science instruments on the other end. Telescopes collect more light than the human eye.
When Hubble slowly degrades and eventually stops working, it will continue orbiting Earth until it's fully decayed, at which point it will spiral towards Earth (and hopefully land in the ocean).