Short answers, pulled from the story.
The primary goal involved investigating communications interference caused by solar flares and auroral activity. Scientists needed to understand how these space weather events disrupted radio signals while passing over high-latitude regions repeatedly.
Vandenberg Air Force Base served as the launch site for this military operation in California. The rocket carried the salvaged satellite from that location toward the polar regions after ignition completed successfully.
Budget constraints forced them to retrieve a previously displayed satellite from the National Air and Space Museum instead of building new hardware. This reuse of a decade-old display model cut development costs significantly compared to designing from scratch.
Engineers at Johns Hopkins University's Applied Physics Laboratory began designing the craft in the early 1980s. They received the designation STP P87-1 or STP P87-A for this specific task assigned by the U.S. Air Force.
Polar BEAR continued the work initiated by the previous HILAT mission which stood for High Latitude. This new craft built upon that foundation with updated instruments and sensors to provide data on similar phenomena.