Schoolboy Nico Marquardt had calculated that if the asteroid hit a satellite in 2029 it would be more likely to hit Earth on its return from the Sun in 2036.
"Nasa offices involved in near-Earth object research were not contacted and have had no correspondence with a young German student who claims that the Apophis impact probability is far higher than the current estimate," said the Near-Earth Object Program Office at Nasa's Jet Propulsion Laboratory in Pasadena.
"This student's conclusion is reportedly based on the possibility of a collision with an artificial satellite during the asteroid's close approach in April 2029.
"However, the asteroid will not pass near the main belt of geosynchronous satellites in 2029, and the chance of a collision with a satellite is exceedingly remote."