[WilliamEdward]

There's a reason most of these comments are saying this is impossible.

First you need some actual technical knowledge, like PhD level knowledge of some slightly innovative new space tech. I like to think one of the big boys in space money will be asteroid mining. So present a detailed and well researched pitch to some investor about how you would go about using a company to RnD this endeavour. Hopefully, they give you a lot of money.

But you said you want little external funding, so, yeah, not going to happen.