BBC Focus Magazine

[nemisis39]

From the blog were due a hit in 2181they state that if the asteroid wasn't spotted till 2080 it wouldn’t have given us enough time to come up with a effective defence. The question i was pondering was, why don't we have an effective defence already or at least looking into it. I no were monitoring and mapping potential destructive asteroids but what is the point in mapping them if we don’t have an effective defence against them

[M Paul Lloyd]

Anything could happen in the next one hundred and seventy odd years, chances are a tiny, but unforseen, change in its current orbit may mean it will miss us anyway.

[The Beige Avenger]

Ok, so Dave Cameron reveals that he's contributing a few hundred million towards the new anti-asteroid, definitely not Star Wars, definitely not for turning towards Earth, device...

You gonna be happy?

[nemisis39]

depends on what you believe BA, there could already be a existing defence against this type of thing a star wars style system with alternative use's with current stealth tech it is quite possiable that it already exists. The point i was making or trying to is the fact that we know that there are chance's albeit slim ones that we could be hit by something from space that we as a planet should have in place some sort of defence system. Also as MPL states, even the slimest of movement in any given objects orbit would more than likely take that threat away anyway assumeing that the movement is in our favour of course

[Shadowwolf]

Oh I very much doubt that there is any secret defence system, likely some secret weapons systems for terrestrial deployment but nothing beyond that.

Given that we have and are developing technologies in the space realm we should probably be developing the means to shift asteroids, however budgets are a tad limited and not helped by the threat being a bit less in our face what with it being far off and not guaranteed to hit.

[Hyrulian Outlaw]

Anything could happen in the next one hundred and seventy odd years

Or indeed in the next half hour.

I'm sure I read a few weeks ago that "scientists" had decided that far from being the destructive, comet shattering, multiple rain of fire and death that it was proposed, that a simple nuclear detonation of any inbound earth striking projectile would actually suffice. It would alter the course of any asteroid but I can't help thinking that the variables must be huge so how can they so sure.

I rather like the idea of a giant mirror array that would focus the rays of the sun into a magnifying glass, giving us a space laser that requires us to merely point and shoot. Though i'm sure if this was a viable option it would already be pointed at various locations around the planet just waiting for someone to annoy who ever owned it enough, all very hush hush of course and no doubt it would be the work of aliens

[M Paul Lloyd]

Actually focussing light from the sun onto an asteroid so as to vapourize its surface would impart a degree of thrust that would alter the asteroids trajectory...... but as to whether that would be a good idea, I really wouldn't like to say.

[nemisis39]

there is something like that in the pipe line

from here
http://www.planetary.org/programs/projects/mirrorbees/

So just what are Mirror Bees?

This new technique involves many small spacecraft -- each carrying a mirror -- swarming around a dangerous asteroid. The spacecraft could precisely tilt their mirrors to focus sunlight onto a tiny spot on the asteroid, vaporizing the rock and metal, and creating a jet plume of super-heated gases and debris. Alternatively, the satellites could contain powerful lasers pumped by sunlight, and the lasers could be used to vaporize the rock. The asteroid would become the fuel for its own rocket -- and slowly, the asteroid would move into a new trajectory.

Major questions still remain about this technique. For example, will the plume of superheated gasses ejected from an asteroid dissipate, or will it block sunlight to the mirrors? Would the debris settle on the satellite mirrors? Can the asteroid's rotation be dealt with effectively? Will the gas plumes be enough to deflect the asteroid?

Although i would have thought that placeing mirrors as opposed to using spaceships would have been more economical

[M Paul Lloyd]

You need the spacehips to help the mirrors keep up with the asreroid.

Me, I would try to use the solar wind.

[nemisis39]

Good point

i was thinking along the lines of having reflective mirrors aligned, so a laser or some such could be fired bouncing along a the mirrors. A little like the pool shot lister used in red dwarf season 4 Whitehole to plug up a whitehole

http://www.reddwarf.nildram.co.uk/rdepisode.htm#4

[M Paul Lloyd]

Problem with mirrors is, what would happen if due to some error/solar storm/accident some of them started pointing at the Earth?

[nemisis39]

Problem with mirrors is, what would happen if due to some error/solar storm/accident some of them started pointing at the Earth?

Everyone would get a suntan I would imagine there would be some sort of computer guidence or control system to keep the mirrors in the right postion. A tracking programe of some sort maybe

[M Paul Lloyd]

And then one large solar flare reboots the on board systems and hey presto, they think its launch time all over again.
Never trust a tracking programme I say.

[worldmaker]

Free floating mirrors would work better on comets (big snowballs) while alternatives would have to be found for comparable thrust-to-cost ratios on asteroids.

I've long thought of thrusters anchored on/around them to put them into safer, and commercially attractive orbits, then mine them for anything useful.