On June 30, 1983, the International Sun-Earth Explorer-3 spacecraft (ISEE-3) was at an apogee of 236 earth radii (RE) exploring particle and field phenomena in the earth's distant magnetic tail region. Most of what we know about the earth's magnetotail is based on spacecraft observations made inside of the lunar orbit distance (approximately 60 RE), and a few brief passes of several interplanetary spacecraft through the more distant tail. ISEE-3 is greatly extending the exploration of the geotail by spending a large part of 1983 in the earth's magnetic tail between 60 and 240 RE.
There will be a special session at the 1983 AGU Fall Meeting which will focus on the new geotail results. In December, ISEE-3 will make a final lunar swing-by, coming within 100 km of the surface of the moon. This maneuver will propel ISEE-3 out into the solar system, where it will pass through the tail of comet Giacobini-Zinner in early September 1985. Later, in March-April 1986, ISEE-3 will monitor the solar wind conditions near Halley's comet while other spacecraft from around the world get a close-up view. ISEE-3 celebrated the fifth anniversary of its launch on August 12.