Triton said:
I object to the idea that a comet or asteroid impact within the next twenty to thirty years is a good thing. I want other drivers for the creation of a space transportation infrastructure.
Oh, I dunno. From a philosophical point of view, I like the idea. This crystalized for me back around Saturnalia, 2004, when asteroids 2004 MN4 (aka Apophis) started hitting the news. At the time, it was looking not impossible that it might plow into Earth in 2036... 32 years in the future. At about a thousand feet in diameter, it masses something like 40,000,000 tons... a big rock, but not a Dinosaur Killer. It would wipe out a country and trash the environment for a bit, probably bring civilization to its knees. But it was also far enough out, and "small" enough, that mankind could *easily* prevent the impact. Even if it took twenty years to get the mission in place, it'd still leave ten years to get it done.
So, what did we have: a possible source of DOOM, but a doom we can do something about if we are smart and non-lazy. Well, what would our options be?
1) Sit back and wait for Odin to come riding in to our rescue.
1A) Odin rides in. Yay. We're saved.
1B) Odin doesn't ride in. D'oh. We're doomed.
2) We go take care of it ourselves
2A) We're successful. Yay, us.
2B) We fail. D'oh.
3) We squabble and fingerpoint and duck responsibility.
3A) D'oh.
3B) D'oh.
This would have been a test humanity *could* pass. But if it chose not to... then perhaps we as a species *deserve* to go the way of some dumbass who decides on a dare to go stand in front of traffic or play Russian Roulette or ignore that smell of smoke coming from the basement or make the beast with two backs with random strangers in the middle of the AIDS epidemic or not evacuate from the shoddily constructed house in the path of the Category Eleven hurricane. Monumentally stupid behavior has obvious and virtually inevitable consequences.
The sooner/bigger the impact risk, the more difficult the interception mission. But something a lot bigger and closer than Apophis can be conceivably diverted, so long as humanity chooses to do so.
And if humanity takes up the challenge and succeeds... then we as a species will come out *awesome.* Let's say the threat is so dire that whole national economies get diverted to the effort. Well, hell... a five-year effort that turns the US FedGuv budget from Social Security, Medicare and a little bit of Military into a whole lot of Space Launch would be better for *everybody.* Kick *everybody* currently on unemployment insurance and EBT off unemployment insurance and EBT and tell them that if they want to eat they'd better get on the work crews... holy Hel, that alone would be worth the risk of impact!