Elon Musk, the billionaire founder and CEO of the private spaceflight company SpaceX, wants to help establish a Mars colony of up to 80,000 people by ferrying explorers to the Red Planet for perhaps $500,000 a trip.
Relevant Sagan quote:
(...) we've put all our eggs in one basket. If we were on many worlds and were to mess up down here, there's a way for the human species to continue. I don't for a moment propose that the Earth is a disposable planet, and we have to put enormous efforts into making sure we don't muss up down here. But there is a chance.
This should also at least somewhat reduce the x-risk stemming from uFAI (a subset of uFAI's may not concern themselves with space travel), and may significantly reduce the x-risk posed by many other x-risk categories (bioengineered threats, catastrophic climate change, global nuclear catastrophe, grey goo scenarios, etcetera).
For total x-risk reduction, prima facie it's unclear to me how supporting an endeavor such as Musk's stacks up against the SI's effectiveness, measured by total x-risk reduction per donated currency unit.
What's with the obsession with planets, anyways? Provided we have the technology to survive on another planet, it seems substantially cheaper to use that technology to survive in space, instead. Gravity wells are expensive.
Article on space.com