Which observatory/satellite was launched into space first, Hakucho or Chandra X-ray Observatory?
Chandra X-ray Observatory 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 .
Nordic Optical Telescope The Nordic Optical Telescope (NOT) is an astronomical telescope located at Roque de los Muchachos Observatory, La Palma in the Canary Islands. The telescope saw first light in 1988, and was officially inaugurated during September 1989. Regular observing started in 1990. It is funded by Denmark, Sweden, Norway, Finland, and (since 1997) Iceland. Access is provided directly to astronomers of the funding countries, and of all nationalities through international time allocation committees.