Comet landing

The rock that killed the dinosaurs was 10km across and would be very trackable and findable well in advance by the instruments of our time. We have so far discovered 865 near earth objects larger than 1km, all of which the orbits are being tracked precisely, so for all of these objects we would know WELL in advance of their impending impact with the earth and work together to change their path at the best time to do so. A

Intercepting a NEO is easy and has been accomplished many times. What to do at the intercept is problematical, though most scientists agree that changing its orbit is the best course of action.

Discovery rate of 1km+ asteroids by year:

2000 - 93
2001 - 67
2002 - 71
2003 - 57
2004 - 50
2005 - 49
2006 - 30
2007 - 28
2008 - 21
2009 - 14
2010 - 12
2011 - 19
2012 - 18
2013 - 10
2014 - 11 (so far).

Now the goal is to find 90%+ of the objects 140m (500 feet) or larger.

Quote: boymimbo

The rock that killed the dinosaurs was 10km across and would be very trackable and findable well in advance by the instruments of our time.

Quite possibly. But asteroids, and comets more so, have rather chaotic orbits, easily disturbed by the planets. A really long period comet could be heading straight for us right now, but it's so far away we haven't seen it.

Quote:

Intercepting a NEO is easy and has been accomplished many times. What to do at the intercept is problematical, though most scientists agree that changing its orbit is the best course of action.

For a major body, it's the only course. the only alternative is to let it hit and cause major damage to our selves and our world.

The problem lies in altering the trajectory. there are three main methods:

1) Rockets. This is pretty simple to explain. You strap a rocket to the offending object and change its speed and thus its orbit. So it will either intersect the Earth's orbit before or after it would have done so. the problem is getting the many, many, many tons of fuel that would be needed all the way to the asteroid; perhaps millions of tons would be needed, or even more than that.

2) Mass drivers. This is essentially the rocket idea, but using the asteroid's or comet's own mass to alter the orbit. The way to do it is by hurling pieces of the intruder at high speed, with the use of things like a magnetic launch track. Essentially this is what a rocket does, and it works the same way: by Newton's third law of motion, for every action there is an equal and opposite reaction.

3) Explosives. Of course this means nuclear explosives. this would be the cheapest means, and also the own with easier and cheaper backups. The idea is to detonate the nuke a short distance from the surface of the asteroid or comet, and use the shockwave (made from the evaporating bomb casing and components), to impart or remove energy from its orbit. The other advantage is that you can send several nukes and detonate them in sequence, if needed. The disadvantage is that without knowing the composition and structure of an object, you risk breaking it up in several pieces, each with its now independent trajectory.

there are other exotic methods like strapping solar sails to comets or asteroids, blasting them with high-powered lasers, shining high-powered lasers on a solar sail strapped to the intruder, and variants on the rocket idea by use of ion engines and nuclear engines.