Which observatory/satellite was launched into space first, Hakucho or Chandra X-ray Observatory?
Hakucho Hakucho (also known as CORSA-b before launch) 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 by the ISAS M-3C-4 rocket on February 21, 1979 and reentered the atmosphere on April 16, 1985 .
Constellation-X Observatory The Constellation-X Observatory (HTXS or Con-X) was a mission concept for an X-ray space observatory to be operated by NASA; in 2008 it was merged with ESA and JAXA efforts in the same direction to produce the International X-ray Observatory project, announced on July 24, 2008.