We Could Get to Neptune and Back in 5 Years for a Mere $4 TrillionS

Manned spaceflight is an expensive and impractical proposition. But what if we had all the funds we wanted at our disposal? What could we do? Quite a bit, it turns out.

Johns Hopkins' Applied Physics Laboratory recently did a study that examines what sorts of missions we might be able to undertake in the latter half of this century.

Sure, some of the tech, like an "onboard 100MW nuclear reactor powering magnetoplasmadynamic thrusters," don't quite exist yet. But they should in another 50 years. And we'll need all that power to send people moving faster than any spacecraft ever has before.

Speed is of the essence because of the danger of cosmic radiation. Rather than slap on a 4240-ton aluminum shield to protect the crew, it would make more sense to just make the trip as short as possible by going really fast. Hence that crazy engine.

But with that lower weight without the shield and the aforementioned engine, it could be possible to get as far as Neptune and back within 5 years, limiting the radiation exposure to those on board.

It wouldn't be cheap, however. The estimate? $4 trillion. Yes, that's more than the entire US federal budget last year. But hey, maybe by 2060 we'll have a lot more money to play with. It could happen! Please, let it happen. [Study Link; Ars Technica]