Why ion engines barely push harder than a sheet of paper and how that whisper of thrust is quietly rewriting the economics of deep space exploration

NASA's most powerful flown ion engine produces just 237 millinewtons of thrust, roughly the weight of a sheet of paper. The 2028 SR-1 Freedom mission will quadruple that figure using a 20 kilowatt nuclear reactor, and in doing so, rewrite the cost structure of every deep-space mission that follows.