Prior to installation, technicians inspect the primary mirror of the Hubble Space Telescope (HST). The first in a series of great observatories launched by NASA, Hubble was designed to last approximately 15 years. The Marshall Space Flight Center had management responsibility for the development of Hubble and played a major role in ground tests and orbital checkout of the telescope. Hubble was launched April 24, 1990, aboard Space Shuttle Discovery's STS-31 mission.