In this historical photo from the U.S. space agency, in the Vehicle Assembly Building, Ken Strite, NASA Quality Control, inspects the connection between Space Shuttle Discovery and the external tank that will be used to launch mission STS-103 in early December of 1999.
This 10 day mission is designed to replace aging parts on the nine year old Hubble Space Telescope and to upgrade some of its functioning systems. During the flight, the astronaut crew will replace all six of the observatory's gyroscopes, a fine guidance sensor, its main computer, and other equipment.
Each weekday, SPACE.com looks back at the history of spaceflight through photos (archive).