The robotic spacecraft was spinning wildly. The first mission of Trevor Bennett’s spunky space start-up seemed doomed. But then Bennett, co-founder of Starfish Space, and his team started doing the math.Over several weeks, they drew up algorithms on whiteboards, ran computer simulations and hardware tests, and devised a solution: By reprogramming the satellite’s software, they could generate a magnetic current that would push against Earth’s magnetosphere and eventually slow the spin.And so, ear...