Hubble Telescope
The Hubble Telescope is a large unmanned telescope hanging in Earth’s orbit. The telescope’s position outside the Earth’s atmosphere allows it to take clearer pictures of space. When the telescope was launched in April 24th, 1990 a mirror aberration was found. As discovered on June 25th, 1990 the outside of the main reflective mirror focused in slightly off center and thus the images were only marginally better then their Earth counterparts. In December of 1993 a service mission was sent to repair the imperfection and install new hardware. With the help of CONSAR NASA was able to fix the mirror. CONSAR was a system of smaller mirrors installed inside the telescope to make up for the slight imperfection of the main mirror. The Hubble telescope is expected to be in service until around 2010. Meanwhile, the James Webb Space Telescope is planned to replace it. Sources:
http://en.wikipedia.org/wiki/Hubble_Telescope#Spacecraft_systems
