This is an interesting point that has worried me in the past. The clock is ticking on this planet, and this solar system. But the more I've thought about it, the less convinced I am that this really justifies manned exploration at its current costs.

It will take some big changes to make space more habitable than Earth. If we can make a survivable enclosure in space, odds are that we can make a survivable enclosure on Earth and save the fuel costs, keeping us closer to some nifty raw materials. Massive impacts might make that unsafe,[0] but mostly we're looking at being engulfed by the sun in 5 billion years as a hard stop.

It's hard to really comprehend how much time that is. It's ten times longer than primates have been around. It's almost 1.5 times as long as all life has been around. Humanity as we know it will no longer exist at that point. If we have living descendents, they could be as unrecognizable to us as apes are to amoebas.

At that point we're just planning for "life in general" to survive, which we could accomplish by just sending probes with some spores or dormant bacteria on long voyages to distant habitable planets.

I wouldn't generally recommend procrastination, but this is probably a problem we can kick down the road a few generations. If we hit snooze for just 1/5000th of the remaining time we have, that'd give us a solid million years to up our technological game before tackling interstellar travel. At that point, the problem will probably have become either trivial or hopeless.

So ultimately, I'm not yet convinced that human survivability experiments are 1000 times as urgent as telescopes, probes, and rovers. That's what I'd be looking for to justify manned's absurd cost premium.

I was actually hoping this article would convince me otherwise, but if put up next to the top things we've learned from unmanned space experiments, I don't think it would compare very favorably. Definitely not 1000 times favorably.

I think we all yearn for the stars, and know this is the sort of thing we want to conquer, we want it to be among the great triumphs of humanity. But if we really want it, we should be smart about it. There's so much low hanging fruit we can get from unmanned. It could aid technological progress and deep understanding of the universe, leading to breakthroughs that ultimately leapfrog us past some challenges we'd meet if we just tried to bang our head against colonization today.

[0] Note that mammals have survived some crazy impacts before, probably by living underground. If we can make a survivable enclosure underground or under the ocean, that will be easier than making one and then launching it into space. Also, near earth object detection and mitigation programs are probably the best way to improve humanity's survivability given current technological capacities (ie, we can't build megastructures in space yet), and those programs compete for NASA money against humans in space too! Gradual climate change is unlikely to make Earth less habitable than Venus or Mars or space. Even if we lost most of our atmosphere and temperatures began to fluctuate by +/- 50 degrees, there'd still be advantages to building controlled structures on Earth rather than building such structures and launching them into inhospitable space. There are degrees of inhospitably, and Earth would have to become nightmarish (eg, probably engulfed by the sun) before we left.