NASA's Chandra X-ray Observatory was launched by Space Shuttle Columbia in July 1999. It is considered to be the most sophisticated X-ray observatory built to date. Chandra is designed to observe X-rays from high-energy regions of the universe, such as the remnants of exploded stars.
XMM-Newton, the European Space Agency's X-ray Multi-Mirror satellite, is the largest science satellite ever built in Europe. XMM-Newton carries three advanced X-ray telescopes, each containing 58 high-precision concentric mirrors. The mirrors are nested and optimized to provide a large collecting area for X-ray detection.
The Hubble Space Telescope was launched into orbit using the Space Shuttle Discovery in 1990. Since then, service calls by shuttles have upgraded Hubble with state-of-the-art instrumentation. Hubble utilizes imaging cameras and spectrometers that have provided unprecedented observations of planets, stars, quasars, and galaxies.
FUSE, launched into orbit aboard a Delta II rocket in June 1999, observes light in the far ultraviolet portion of the electromagnetic spectrum (approximately 900 to 1200 angstroms). FUSE observes these wavelengths with much greater sensitivity and resolving power than previous instruments used in this wavelength range.