The Hubble repair crew

The crew of STS-61 (Dec 1993) - the first to repair a space telescope: commander Story Musgrave, pilot J. Michael Smith, and mission specialists including John Hunsaker and Mary Cleave.

Hubble launched in 1990 with its main mirror ground incorrectly - a spherical aberration that compromised the telescope. The STS-61 crew spent weeks in space installing COSTAR, a corrective optics device, and a new camera, and 'the optics were corrected to their intended quality'. Hubble is the only telescope designed to be maintained in space by astronauts: five shuttle missions repaired, upgraded and replaced its systems, including all five of the main instruments (the last in 2009). The most famous mistake in astronomy history, fixed by hand.

Built on the Space Shuttle program and on Hubble's serviceability design (the telescope was built to be repaired). Enabled Hubble's three decades as the most productive telescope in history - it completed 30 years of operation in April 2020.