Astronaut Missions

On April 24, 1990, the space shuttle Discovery lifted off from Earth with the Hubble Space Telescope nestled securely in its bay. The following day, the crew released Hubble into orbit, ready to peer into the vast unknown of space.

SM1 (which took place in December of 1993) was the first opportunity to conduct planned maintenance on the telescope. Astronauts installed new instruments, including equipment adjusted to correct for the flaw in Hubble's primary mirror.

During SM2 (February 1997), astronauts installed new instruments that extended Hubble's wavelength range into the near-infrared, allowing scientists to probe the most distant reaches of the universe. They also replaced failed or degraded spacecraft components to increase efficiency and performance.

Originally planned as a maintenance mission, SM3 became more urgent with the failure of the fourth of Hubble's six gyroscopes, which stabilize the telescope. NASA split the third servicing mission into two parts to bring Hubble back into operation more quickly. In SM3A (December 1999), astronauts replaced all six gyros and installed a more powerful computer, a new transmitter, new insulation, and other equipment.

During SM3B (March 2002), astronauts replaced Hubble's solar panels and installed the Advanced Camera for Surveys, which took the place of the Faint Object Camera, Hubble's last original instrument.

Hubble was reborn with SM4 (May 2009), in which astronauts installed two new scientific instruments and brought two more failed ones back to life by the first-ever on-orbit instrument repairs. They also further extended Hubble's life with new batteries, new gyros, and a new science computer. In addition, a device was attached to the base of the telescope to facilitate de-orbiting when the telescope can no longer perform science.