The Yohkoh Mission is a Japanese Solar mission with US and UK collaborators. It was launched into Earth orbit in August of 1991 and provided valuable data about the Sun's corona and solar flares. The satellite carried four instruments - a Soft X-ray Telescope (SXT), a Hard X-ray Telescope (HXT), a Bragg Crystal Spectrometer (BCS), and a Wide Band Spectrometer (WBS).

MSFC Solar Physics Group members Ron Moore, Jason Porter, David Falconer, and Alphonse Sterling have been involved in analyzing some of these images to determine the nature of the magnetic connections in the solar atmosphere and characteristics of flare-like activity.

Yohkoh suffered a spacecraft failure in December 2001 that has put an end to this mission. During the solar eclipse of December 14th the spacecraft lost pointing and the batteries discharged. The spacecraft operators were unable to command the satellite to point toward the sun.