MITS was an acronym: "Micro Instrumentation and Telemetry Systems". Ed Roberts and Forrest Mims made electronics kits for model rockets.
As a 1970s kid, I built Estes rockets, but I never did anything fancy. You'd spend a week or two of free time, building the kit and painting it. Then you'd blow it up on the launch pad, or launch it into the wild blue and never see it again. Or spend all your birthday money on a Star Wars X-Wing fighter, launch it, and have it nose-dive into the dirt about ten feet away.
Come to think of it, model rocketry was exactly like real rocketry.
Forrest Mims enriched my life in other ways, with his patient lab manuals for the Radio Shack electronics kits.