How the Hubble Telescope became the 'Energizer bunny of spacecraft,' according to one of its astronaut visitors

The Hubble Space Telescope stands tall in the cargo bay of the Space Shuttle Atlantis following its capture and lock-down in Earth orbit.

John Grunsfeld has a model of the Hubble Space Telescope on his bookshelf. It's right next to a model of a NASA space shuttle, which delivered Hubble to space 35 years ago, and it's no secret why both are there.

Grunsfeld, a former NASA astronaut who has served as both the agency's chief scientist and science division leader, helped Hubble last as long as it has. He flew on no less than three of NASA's five fix-it missions to the iconic Hubble Space Telescope between 1999 and 2009. That final mission was the STS-125 servicing flight on the shuttle Atlantis, which NASA thought would give Hubble at least five more years of life, though the agency hoped to stretch that to 15 years. Next month, NASA will mark the 16th year since that final Hubble service call.