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 .
Greenhouse Gases Observing Satellite The Greenhouse Gases Observing Satellite (GOSat), also known as Ibuki (Japanese: いぶき , Hepburn: Ibuki , meaning "breath") , is an Earth observation satellite and the world's first satellite dedicated to greenhouse-gas-monitoring. It measures the densities of carbon dioxide and methane from 56,000 locations on the Earth's atmosphere. The GOSAT was developed by the Japan Aerospace Exploration Agency (JAXA) and launched on 23 January 2009, from the Tanegashima Space Center. Japan's Ministry of the Environment, and the National Institute for Environmental Studies (NIES) use the data to track gases causing the greenhouse effect, and share the data with NASA and other international scientific organizations.