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 .
SNAP-1 SNAP-1 is a British nanosatellite orbiting in Low Earth Orbit. The satellite was built at the Surrey Space Centre by Surrey Satellite Technology Ltd (SSTL) and members of the University of Surrey. It was launched on 28 June 2000 on board a Kosmos-3M rocket from the Plesetsk Cosmodrome in northern Russia. It shared the launch with a Russian Nadezhda search and relay spacecraft and the Chinese Tsinghua-1 microsatellite.