History of X-Ray Astronomy
ASCA (Advanced Satellite for Cosmology and Astrophysics) was a joint mission by Japan and the United States. The ASCA X-ray observatory, launched in 1993, was especially designed to study the detailed distribution of X-rays with energy, which provide important information about the elements that make up the hot X-ray emitting gas. ASCA ceased operations in July of 2000.
The Rossi X-ray Timing Explorer (RXTE) is a NASA mission which was launched in December 1995. Although RXTE does not have focusing X-ray mirrors, it has the unique capability to study rapid time variability in the emission of cosmic X-ray sources over a wide band of X-ray energies, and is expected to make valuable contributions to our understanding of neutron stars and black holes.
BeppoSAX was a program of the Italian Space Agency with participation of the Netherlands Agency for Aerospace Programs. It was launched on April 30, 1996 from Cape Canaveral, and was the first X-ray mission with a scientific payload covering more than three decades of energy - from 0.1 to 300 keV, with moderate imaging capability. BeppoSAX proved to be useful for X-ray imaging sources associated with Gamma-ray bursts, determining their positions with unprecedented precision, and monitoring the X-ray afterglow. All in-orbit operations of the BeppoSAX mission ended in April, 2002. In April 2003, the spacecraft re-entered Earth's atmosphere and splashed down in the Pacific Ocean.
XMM (The High-Throughput X-ray Spectroscopy Mission) is a large X-ray astrophysics observatory developed by the European Space Agency. It was launched on December 10, 1999. This facility class observatory, with an anticipated lifetime of ten years, will enable astronomers to conduct sensitive X-ray spectroscopic obsverations of a wide variety of cosmic sources, and should be a powerful complement to Chandra.
Revised: January 29, 2008