Hakucho (also known as CORSA-b before launch; CORSA stands for Cosmic Radiation Satellite) was Japan's first X-ray astronomy satellite, developed by the Institute of Space and Aeronautical Science (then a division of the University of Tokyo). It was launched from the Kagoshima Space Center by the ISAS M-3C rocket on the M-3C-4 mission on February 21, 1979 and reentered the atmosphere on April 15, 1985. Hakucho was a replacement for the CORSA satellite which failed to launch due to rocket failure on February 4, 1976. Highlights Discovery of soft X-ray transient Cen X-4 and Aql X-1 Discovery of many burst sources Long-term monitoring of X-ray pulsar (e.g. Vela X-1) Discovery of 2 Hz variability in the Rapid Burster later named Quasi Period Oscillation. See also Timeline of artificial satellites and space probes References isas.jaxa.jp heasarc.gsfc.nasa.gov Satellites formerly orbiting Earth X-ray telescopes Satellites of Japan 1979 in spaceflight Spacecraft launched in 1979