1.1. MISSION BACKGROUND The scientific objective of this magnetospheric physics mission was a detailed in vestigation of the Aurora Borealis, or 'Northern Lights'. The fields experiments (electric and magnetic) were constructed by the University of California at Berke ley (UCB), and Los Angeles (UCLA) respectively. The particles instruments were constructed by UCB and the University of New Hampshire in collaboration with Lockheed Palo Alto Research Laboratory. The instrument data processing unit was provided by UCB. The spacecraft bus, telemetry, and launch services were provided by the NASA Goddard Space Flight Center SMEX office. The science principal investigator is Dr C. W. Carlson of UCB, and the program is managed by the SMEX office. The UCB design philosophy emphasizes the demonstration of design margins set by peer review. As a result, each boom system was extensively tested at a prototype level before the flight units were manufactured. Additionally, the design, assembly and testing of each boom mechanism was conducted by a single engineer solely responsible for its success.