Chinese Moon Probe heads towards L2

http://science.slashdot.org/story/11/06 ... eedfetcher

Anybody know why they are heading towards L2 i would have thought the possibility of finding something interesting would be more likely at L4 or L5 does it take much more energy to get to either of those? as they are doing extra pure science after a successful mission its not really that much of extra risk is it.?

Its easier to get there from lunar orbit than any other L point. All you really have to do is time your lunar escape burn to match its apogee with the vicinity of the point. Get it right and you are left with just the right velocity to park at L2. Where as L4,5, or even 1 you have to change your solar orbit quite a bit if you don't have a likewise convenient Hohmann transfer you can take advantage of.

They may not have had the gas to get anywhere else or want to risk losing it (literally) with a much further trip away from home.

I just hope China has already sufficient skills at sending a probe to L2 and at station keeping once there, that they do not smack into Herschel or Planck

Well its not a parking lot at least.