Space: The final frontier..?

[kojikun]

china had some ideas based on american designs for a spaceplane that would ride atop a rocket. silly idea, like all spaceplanes.

[Kurgan]

Assuming of course, we don't find massive deposites of some valuable resource like plutonium or oil/coal or something on the moon/mars or other nearby planets, the biggest reason I can think of is the survival of the species.

We risk extinction from not just the usual stuff (diseases, war, pollution, etc) but asteroid impacts.

Sooner or later, one of those big asteroids may hit us and we go the way of the dinosaurs. If we don't have "all our eggs in one basket" that could help ensure our survival (and if our species happen to be around in 4-5 billion years, we better have found a way to leave our solar system... heh).

So ultimately long-term survival, although those other things (fighting overpopulation, resources, knowledge, exploration for its own sake, etc) are nice side benefits.

[Sea Skimmer]

Screw space. We need Seaquest DSV!

Transparent water tight doors are the future

Hydrogen peroxide would be another oxidizer. You can use it instead of LOX, but it has problems of its own. And you still need fuel to make the rocket go. Alcohol burned with hydrogen peroxide would be usable.

The V-2 used alcohol and liquid oxygen

[kojikun]

we already found those deposits Kurgan: Helium-3 on the moon and in the gas giants, almost endless supplies of precious metals in the asteroids.. But an offworld colony or 10 would help incase we nuke ourselves to oblivion or do something else to make it impossible for us to survive here.