Hubble Space Telescope is a well-equipped observatory, in some ways
the most powerful telescope ever sent into space. Its mirrors direct
light from astronomical objects to various detectors. The suite
of scientific instruments includes cameras, spectrographs to split
up and analyze the light, and sensors that help to point the telescope
and also measure the distances of astronomical objects.
instruments have been designed to be serviced in orbit. During periodic
visits by Space Shuttle astronauts, new instruments can be exchanged
for old ones, batteries and many other components can be replaced,
and newer technology can be installed.