Hubble Space Telescope

Floating in orbit approximately 380 miles (612 km) above the earth, the 12.5-ton Hubble Space Telescope has peered farther into the Universe than any telescope before it. The Hubble, which was launched in 1990, has produced images with unprecedented resolution at visible, near-ultraviolet, and near-infrared wavelengths since its originally faulty optics were corrected in 1993. Although ground-based technology is finally starting to catch up—the European Southern Observatory's Very Large Telescope atop Cerro Paranal, Chile, can now produce narrow-field images even sharper than Hubble's—the Hubble continues to produce a stream of unique observations. Over the last decade, the Hubble has revolutionized astronomy.

The Hubble was the first of the four great observatories planned by the United States. National Aeronautics and Space Administration (NASA). This series of orbital telescopes also includes the Compton Gamma Ray Observatory (launched 1991), the Chandra X-Ray Observatory (launched 1999), and the Space Infrared Telescope Facility (scheduled for launch in 2003). Together, the light-sensing abilities of the Great Observatories span much of the electromagnetic spectrum. They are designed to do so because each part of the spectrum conveys different astronomical information.