Photograph courtesy NASA
The Hubble telescope drifts back into space with Earth as its backdrop on Christmas Day 1999 following a successful servicing mission. Seven astronauts aboard space shuttle Discovery completed three spacewalks over six days to replace the telescope's worn and outdated equipment, including its failing gyroscopes, and perform several maintenance upgrades. Astronauts had a firm return day for this mission—they needed to finish their work and return to Earth before New Year's Day to avoid possible Y2K problems. They landed safely on December 27.