Apophis - round and round we go

[LordFerret]

German schoolboy, 13, corrects NASA's asteroid figures: paper

NASA dismisses schoolboy asteroid claims

[Adirondack]

NASA Statement on Student Asteroid Calculations

[Fightspit]

In response to inquiries, accidental impact with an artifical satellite in 2029 is vanishingly unlikely. As mentioned above, (1) Apophis does not pass near the zones where most satellites are located and (2) man-made satellites and Apophis both have small cross-sectional areas. Even if a high-velocity impact occurred, a large satellite could change Apophis' position 7 years later (in 2036) by only 100's of km at most. This is less than 1/10th the size of the smallest issues considered in the paper, very much in the noise of the calculations, and can have no meaningful effect on Earth impact probability estimation (which already incorporates more than 30 million km of uncertainty). At such a late date, impact with an artificial satellite would be like a bug on the windshield of Apophis. Deflection efforts are dependent on being early enough to leverage the dynamics of the 2029 encounter. Events during the encounter lack such leverage.

From: http://neo.jpl.nasa.gov/apophis/ (bottom page)