De-orbit
After one of its gyroscopes failed, the observatory was deliberately de-orbited. At the time, the observatory was still operational, however the failure of another gyroscope would have made de-orbiting much more difficult and dangerous. With some controversy, NASA decided in the interest of public safety that a controlled crash was preferable to letting the craft come down on its own at random. Unlike the Hubble Space Telescope, it was not designed for on-orbit repair and refurbishment. It entered the Earth's atmosphere on 4 June 2000, with the debris that did not burn up falling harmlessly into the Pacific Ocean.
This de-orbit was NASA's first intentional controlled de-orbit of a satellite.
Read more about this topic: Compton Gamma Ray Observatory