Hakuchō

Mission type	X Ray Celestial Observation
Operator	Institute of Space and Astronautical Science (Japan)
COSPAR ID	1979-014A
SATCAT no.	11272
Spacecraft properties
Launch mass	96.0 kilograms (211.6 lb)
Dimensions	⌀760mm×650mm
Start of mission
Launch date	21 February 1979 UTC
Rocket	M-3C-Rocket (mission 4)
Launch site	Uchinoura Space Center, Kagoshima Prefecture, Japan
End of mission
Decay date	April 15, 1985

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 ^[1] and reentered the atmosphere on April 15, 1985.^[2]

Hakucho was a replacement for the Cosmic Radiation Satellite (CORSA) satellite which failed to launch due to rocket failure on February 4, 1976.^[3]

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.