[boltcaster_44]

Umm lets build a giant rubber net, why try to shoot a bullet off course instead of making a bulletproof vest? Lets absorb and capture this asteroid for all its worth $$$

[zinchenko]

Gonna laugh if they change the course of the asteroid... and then that asteroid now has a 100% chance of hitting earth.

[gatagato]

It seems that now China wants to join the party

China Reveals Solar Sail Plan To Prevent Apophis Hitting Earth in 2036
A small shove could prevent a global catastrophe, according to Chinese plans

Apophis is a 46 million tonne asteroid that will pass within a hair's breath of Earth in 2029. However, Apophis's trajectory is likely to take it through a region of space near Earth known as a keyhole that will ensure the asteroid returns in 2036.

Nobody knows how close Apophis will come on that pass. But if there's a chance of a collision, we'll have only 7 years to work out how to avoid catastrophe.

Today, Shengping Gong and pals at Tsinghua University in Beijing say they've come up with a plan that will ensure Apophis never returns to Earth on this timescale .

They point out that keyholes are tiny, in this case just 600 metres wide. So deflecting Apophis by only a small amount in the near future will ensure it misses the keyhole and so cannot return to Earth.

There are various ways to deflect an asteroid. Gong and pals say their preference is to use a solar sail to place a small spacecraft into a retrograde orbit and on collision course with Apophis. The retrograde orbit will give it an impact velocity of 90km/s which, if they do this well enough in advance, should lead to a collision large enough to do the trick.

Putting a spacecraft into a retrograde orbit about the Sun using little or no fuel is a pretty neat trick by anyone's standards.. The Chinese team's calculations demonstrate the point. They show that a 10 kg sail in retrograde orbit, that hits Apophis a year before 2029, would deflect it enough to miss the keyhole, thereby eliminating the chance that the asteroid will return in 2036.

And such a mission ought to be relatively cheap and relatively easy to deploy.

That sounds easy enough. In practice, however, threading this camel through the eye of a needle will be extremely tricky. There are all kinds of variations in the solar wind that could send such a spacecraft wildly off course.

It also requires a huge sail that will be difficult to unfurl and also liable to damage during the course of the journey, which will itself take years.

Then there's the structure and make up of Apophis, which is a complete mystery. Without knowing the material properties of the asteroid, it's impossible to determine how the impact will affect it.

So there's a little more work to be done in Beijing before this plan can get off the ground. Perhaps they should team up with the Europeans.
http://www.technologyreview.com/blog/arxiv/27088/

Utilization of H-reversal Trajectory of Solar Sail for Asteroid Deflection
Authors: Shengping Gong, Junfeng Li, Xiangyuan Zeng

Near Earth Asteroids have a possibility of impacting with the Earth and always have a thread on the Earth. This paper proposes a way of changing the trajectory of the asteroid to avoid the impaction. Solar sail evolving in a H-reversal trajectory is utilized for asteroid deflection. Firstly, the dynamics of solar sail and the characteristics of the H-reversal trajectory are analyzed. Then, the attitude of the solar sail is optimized to guide the sail to impact with the object asteroid along a H-reversal trajectory. The impact velocity depends on two important parameters: the minimum solar distance along the trajectory and lightness number. A larger lightness number and a smaller solar distance lead to a higher impact velocity. Finally, the deflection capability of a solar sail impacting with the asteroid along the H-reversal is discussed. The results show that a 10 kg solar sail with a lead-time of one year can move Apophis out of a 600-m keyhole area in 2029 to eliminate the possibility of its resonant return in 2036.

http://arxiv.org/abs/1108.3183

[Andria]

Why not blow up Earth and save the rest of the universe from humanity?

[TwistedPrincess]

Originally Posted by Andria ↗

Why not blow up Earth and save the rest of the universe from humanity?

not sure if you are serious or just kidding but i think that's not all that bad of an idea.

after all, we were put on this planet so i guess it is ours to destroy. and we are doing a damn good job of that. but we were not given other heavenly bodies and therefore we have no business trying to destroy them, especially if they are not a threat to us. we don't know for a fact that this asteroid is a threat.

who is to say that this asteroid isn't there to take a hit of something else that is heading towards our planet? we could end up destroying something that meant to protect us.