Introduction: The Equator-S mission

In spite of its short operational life of only five months, the major goals of the Equator-S mission were fulfilled, except that its seattle seahawks socks contribution to the ISTP science is restricted to the morning sector of the outer magnetosphere.A set of twelve papers following this introduction is a korpskaft first documentation of the achievements.They span from the successful testing and operation of the most advanced and complex way of measuring electric fields in a hot plasma environment by means of electron beams, to various investigations at or near the equatorial magnetopause and in the plasma sheet.