WN: Wired News:
"The proposal calls for a $300 million mission to land a transponder on the asteroid, a 1,050-foot-wide body known as 2004 MN4. Signals from the transponder would be used to pinpoint the asteroid's trajectory and determine whether it will strike Earth or simply zoom past.
To date, scientists at NASA's Near Earth Object program have maintained that the likelihood of a strike is miniscule. In 2035, the probability is just 1 in 23,000, according to their calculations. In 2036, that probability rises to a mere 1 in 14,000.
However, those numbers could change after 2004 MN4 passes between Earth and the moon in 2029. At that point, astronomers will have a chance to make extensive observations of the asteroid and will be able to calculate the risk more precisely -- for better or for worse.
Finding out in 2029 that the chances of an impact were actually on the order of 1 in 10 or worse would be disastrous because it would be too late to launch a mission to deflect the asteroid, argues Schweickart."
Sounds like a good idea to me. We must defend our planet from asteroids. I mean, we know they have caused mass extinctions before, and that would be nice to avoid.