The Hubble: a mission of discovery

Vast vision

NASA's $1.55 billion Hubble Space Telescope is the country's most expensive unmanned spacecraft. Designed to last 15 years with periodic maintenance by space shuttle crews, the observatory promises to detect objects 50 times more faint with 10 times greater clarity than ground-based telescopes. The 12 ton, 43-foot long observatory will circle the Earth at an altitude of 380 miles.

Key instruments aboard the Hubble Space Telescope

Wide Field/Planetary Camera. Using this instrument, astronomers will search for planets around nearby stars and obtain crisp, regular observations of Jupiter, Saturn, Uranus and Neptune.

Faint Object Spectrograph. By studying exploding stars called supernovae with this instrument, scientists hope to measure the rate at which the expansion of the universe is slowing. If the rate is as slow as some theorists suggest, the expansion may continue forever. If it is rapid, the universe will slow and eventually contract, with all of the matter eventually colliding cataclysmically.

Goddard High Resolution Spectrograph. This instrument will permit astronomers to observe revealing ultraviolet emissions blocked from ground observers by the Earth's atmosphere. Studies of the chemical and physical composition of comets may reveal whether they seeded the Earth and perhaps other planets with water and complex organic elements that formed the basis for life.

High Speed Photometer. Using the photometer, astronomers plan to study the interaction between the dual stars, or star and black hole that comprise what are called binary systems. Past observations reveal that matter from the larger star in a binary system actually flows into a disk of matter around a smaller companion.

Faint Object Camera. It is so sensitive it can photograph objects seven times more distant than ground observatories, a scale that will enlarge the current field of observation in all directions of the sky by 350 times. With more distant horizons, astronomers will search for stars in the earliest stages of formation.