sentences:  The MSU solar group carries on an active research program under NASA and NSF support and is actively involved in day-to-day operation and scientific utilization of satellite missions for studies of the Sun.Acton was a principal investigator for Soft X-ray Telescope (SXT) experiment on the Japan/US/UK Yohkoh mission The Yohkoh mission focused on the study of high-energy solar processes, such as solar flares, eruptions and the heating of the corona.The primary emission of the extremely hot outer atmosphere of the sun, the solar corona, is at X-ray wavelengths.