Satellite-servicing technology is being used to upgrade the Hubble Space Telescope to perform beyond its initial design requirements. Twice astronauts have replaced the telescope's solar panels with higher-performance ones. The most impressive improvement, however, has come with the ______ of a new camera to record the images seen by the Hubble . Its increased sensitivity makes it ten times as powerful as its predecessor, and it has produced dramatically sharper images, some of them of stars and galaxies that were invisible to the old Hubble.