question: Which observatory/satellite was launched into space first, Hakucho or Chandra X-ray Observatory?
answer: Hakucho
context: Title: Martin C. Weisskopf
  Passage: Dr. Martin C. Weisskopf (born April 21., 1942) is project scientist for NASA's Chandra X-ray Observatory and Chief Scientist for X-ray Astronomy in the Space Sciences Department at NASA's Marshall Space Flight Center in Huntsville, Ala.
  Title: Hakucho
  Passage: 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 .
  Title: STS-37
  Passage: STS-37, the eighth flight of the Space Shuttle "Atlantis", was a six-day mission with the primary objective of launching the Compton Gamma Ray Observatory (CGRO), the second of the Great Observatories program which included the visible-spectrum Hubble Space Telescope, the Chandra X-ray Observatory and the infrared Spitzer Space Telescope.  The mission also featured two spacewalks, the first since 1985.
  Title: Chandra X-ray Observatory
  Passage: The Chandra X-ray Observatory (CXO), previously known as the Advanced X-ray Astrophysics Facility (AXAF), is a Flagship-class space observatory launched on STS-93 by NASA on July 23, 1999.  Chandra is sensitive to X-ray sources 100 times fainter than any previous X-ray telescope, enabled by the high angular resolution of its mirrors.  Since the Earth's atmosphere absorbs the vast majority of X-rays, they are not detectable from Earth-based telescopes; therefore space-based telescopes are required to make these observations.  Chandra is an Earth satellite in a 64-hour orbit, and its mission is ongoing as of 2017 .
citations: Chandra X-ray Observatory Hakucho