STS-125

STS-125 was NASA's last chance to visit the Hubble Space Telescope. After the Columbia disaster in 2003, agency leadership had initially cancelled further Hubble servicing missions, judging a Shuttle flight without the safe harbor of the International Space Station too risky for an aging telescope. Public outcry and continued advocacy from scientists and engineers eventually reversed that decision, and Atlantis's mission became the fifth and final servicing call to Hubble.

Commanded by Scott Altman, the seven-person crew included John Grunsfeld, an astronomer-astronaut making his third trip to service Hubble, a personal connection to the telescope unmatched by anyone else who ever flew. Launched on May 11, 2009, Atlantis carried an ambitious repair and upgrade list: two new scientific instruments, replacement batteries and gyroscopes, new insulation panels, and repairs to two existing instruments that had never been designed to be fixed in orbit.

Over five spacewalks, astronauts worked through technically extraordinary challenges, including removing hundreds of tiny screws to access and repair the Space Telescope Imaging Spectrograph and the Advanced Camera for Surveys, instruments whose internal electronics engineers had never intended anyone to touch after launch. The repairs required specially designed tools and meticulous procedures rehearsed for years in advance, and by the mission's end, the crew had installed the Wide Field Camera 3 and the Cosmic Origins Spectrograph, giving Hubble capabilities far beyond its original 1990 design.

Atlantis returned safely to Edwards Air Force Base on May 24, having left Hubble more capable than at any point in its history. The servicing extended the telescope's operational life by more than a decade, and with no further Shuttle visits possible after the program's planned retirement, STS-125 ensured Hubble could continue its scientific work independently for years to come.

STS-125 ensured Hubble's scientific legacy would extend for another decade or more, installing instruments capable of observations far beyond what the telescope's original 1990 design ever anticipated, from studying exoplanet atmospheres to probing the early universe.

The mission's unprecedented in-orbit repairs to instruments never designed for servicing demonstrated the extraordinary technical skill NASA's astronaut corps and engineering teams had developed over three decades of Shuttle spacewalking experience, a capstone achievement for the program's spacewalk expertise.

With no further Shuttle flights capable of reaching Hubble after the program's 2011 retirement, STS-125 also marked a symbolic turning point: the end of an era in which humans could travel to personally repair and upgrade a spacecraft already in orbit, a capability the Shuttle uniquely provided and no vehicle has fully replicated since.