Sorry, Spaceflight fuels. I just heard Fusion is being pushed back a few decades. Not even accounting for the singularity. But that's no matter - todays tried and tested systems will do for all the scientific exploring that's required. Anyone posturing about rocket fuels as some sort of ecological disaster probably needs psychiatric attention. They're like those rolled-gold frauds raving and ranting about Btc burning up oceans. In the spirit of accepting 'reinforcements from the future ' I suggest quantum-computing combined with strong AI will help us upload ourselves and that will, in turn, greatly assist the effort to spread out in this galaxy and colonize back-up and respawn-points in a sustainable and defensible manner. Gassing wilderness planets just so meatspace humanity can pollute new worlds is the losers play. An enders game. But youse knew that.
