Asteroid 1950 DA's Encounter with Earth in 2880: Physical Limits of Collision Probability Prediction
Abstract
Integration of the orbit of asteroid (29075) 1950 DA, which is based on radar and optical measurements spanning 51 years, reveals a 20minute interval in March 2880 when there could be a nonnegligible probability of the 1kilometer object colliding with Earth. Trajectory knowledge remains accurate until then because of extensive astrometric data, an inclined orbit geometry that reduces inplane perturbations, and an orbit uncertainty space modulated by gravitational resonance. The approach distance uncertainty in 2880 is determined primarily by uncertainty in the accelerations arising from thermal reradiation of solar energy absorbed by the asteroid. Those accelerations depend on the spin axis, composition, and surface properties of the asteroid, so that refining the collision probability may require direct inspection by a spacecraft.
 Publication:

Science
 Pub Date:
 April 2002
 DOI:
 10.1126/science.1068191
 Bibcode:
 2002Sci...296..132G
 Keywords:

 PLANET SCI