The Japanese Asuka spacecraft (formerly Astro-D), an X-ray mission .
ASCA (formerly named ASTRO-D) is the fourth cosmic X-ray astronomy mission by Japan's (JAXA), and the second for which the United States is providing part of the scientific payload. The satellite was successfully launched on February 20, 1993. The first eight months of the ASCA mission were devoted to performance verification. Having established the quality of performance of all ASCA's instruments, the project changed to a general/guest observer for the remainder of the mission. In this phase the observing program is open to astronomers based at Japanese and US institutions, as well as those who are located in member states of theEuropean Space Agency