A planning page for asteroids 2009 FD and 2015 TB145 | Hacker News Reader

A planning page for asteroids 2009 FD and 2015 TB145

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36 pointsintrasight17 comments

Don't know about you, but "2015 TB145" scares the shit out of me. What if the projected trajectory was an earth strike. There'd be no time to react. Humanity really needs to get together to address these existential threats.

What could we possibly do to prepare/handle something like this?

Thank god that Hollywood had the foresight to give us a playbook (and live action simulation) for this exact situation: http://www.imdb.com/title/tt0120591/

And http://www.imdb.com/title/tt1307068/ Seeking a Friend for the End of the World

And Deep Impact http://www.imdb.com/title/tt0120647/

There are a whole range of options, if we have enough warning and invest in the technology[1]. My personal favourite is the gravity tractor:

> One more alternative to explosive deflection is to move the asteroid slowly over a time. Tiny constant thrust accumulates to deviate an object sufficiently from its predicted course. Edward T. Lu and Stanley G. Love have proposed using a large heavy unmanned spacecraft hovering over an asteroid to gravitationally pull the latter into a non-threatening orbit.

And the same technology could be used to actively "capture" asteroids for fun and profit

[1] https://en.wikipedia.org/wiki/Asteroid_impact_avoidance

https://en.wikipedia.org/wiki/Asteroid_impact_avoidance

Shoot it with an ICBM. Better to be hit with buckshot than with a slug.

ICBMs reach a velocity of about 5 km/sec., aren't reprogrammable in minutes to shoot at spsce rocks, and US ones at least carry weapons of less than 500 kt. This isn't going to do it. If we want to use nukes, which is questionable, the devices need to already be in high orbit to respond fast enough, have a radar guidance system, and be much more powerful. This is also a recipe to trigger WW 3.

I'm not suggesting it as a "minutes to go" safety measure. More of a "we have tons of rockets with nukes on them that can make it into space" just sitting around measure.

Making it to space isn't enough. They have to be able to escape completely and deliver a very large warhead to the asteroid.

An asteroid that size has a very small escape velocity, on the order of a few meters per second. I think a mass driver which broke off small chunks of asteroid and hurled them to escape would not take too much power and be able to disassemble the asteroid in less than one orbit. (Advanced detection would be a plus here.) If we aimed the ejecta, to get a momentum change in a given direction, we would not have to completely disassemble the asteroid, because its orbit would change and eventually miss Earth. Complete disassembly would be safer, because small chunks would burn up in Earth's atmosphere.

It's an entire 1.3 lunar distances away! Don't sweat it! =p

But yeah, if it were a projected impact, the point of impact on Earth would see the largest evacuation ever. And/or we'd bring in the brightest minds and say you have 10 days, failure is not an option and hopefully history books would be made.

But you learn more from failure.

They could always say: We haven't failed. We just found a way that won't work to not save the human race the next time.

I take it back lol. At that velocity, we'd be screwed. We have nothing that could get something big enough, to a high enough orbit, and at that velocity...So yeah, it's pretty reassuring lol....

According to Wikipedia, a 300m+ impactor is indeed a serious threat. https://en.wikipedia.org/wiki/Impact_event

I think 2009 FD is the worrying one. It's incredibly dark, with a surface albedo of just 0.01. That means optical surveys would struggle to find it in deep space, even when it's half a kilometer wide, even with [0] the LSST telescope in the 2020's.

This is why some people want space-based infrared telescopes for NEO surveys [1].

[0] http://arxiv.org/abs/astro-ph/0701506

[1] http://neocam.ipac.caltech.edu/page/whyinfrared

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