Saving Hubble

The fortunate requirement that enabled the successful repair of Hubble was the telescope's original design philosophy that provided for periodic visits by space shuttle astronauts performing space walks to maintain, repair and upgrade the telescope. The designers of the telescope had planned ahead and provided for orbital replacement units and instruments with standardized and space walk-compatible interfaces. And the telescope itself was designed with built-in astronaut crew aids, such as handrails and tether points, sockets for attaching portable foot-restraint platforms to provide secure work sites, standardized access doors, electrical connector maps and instruction labels.