[omegant]

Well there've been campaigns out there that have reached above $1 mill. It's difficult but doable, I don't know what kind of money will you need this three years, probably it's not worth the (PR) risk of failing to reach the goal quantity. On the other side it could be a way a good PR move on it's own. I'm sure there is some people at YC that are able to give an autoritative opinion.

There it's also the option of getting some scientific teams(universities, institutes) to help in a crowdsourcing way. For no money, just stock and the possibility to help with a world changing project like yours.

I know it's possible because I've got some high level volunteers (NASA, European level matematic institute, Airbus ingeneers) in contact with Dirk Ahlborn (Jumpstart) to work on the Hyperloop (they got more than 80 volunteers selected).

I don't know if having ingeneering, designers and matematician teams working remotely could be helpful to you at this moment, but it's another way to get people around the world to help, and now that you have YC backing it'll be easier.