If we can’t get a monkey alive through the Van Allen Belts, Aliens cannot invade from Alpha Centuri!
We DID get monkeys alive through the Van Allen Belts — people, also.
And if there were such a thing as Aliens from Alpha Centauri — I personally disbelieve in aliens traveling to Earth, period — whether or not they could get through the Van Allen Belts is unknowable, and irrelevant to monkeys and people’s success.