  Satellite conjunctions involving "near misses" of space objects are becoming
increasingly likely. One approach to risk analysis for them involves the
computation of the collision probability, but this has been regarded as having
some counter-intuitive properties and its interpretation has been debated. This
paper formulates an approach to satellite conjunction based on a simple
statistical model and discusses inference on the miss distance between the two
objects, both when the relative velocity can be taken as known and when its
uncertainty must be taken into account. It is pointed out that the usual
collision probability estimate can be badly biased, but that highly accurate
inference on the miss distance is possible. The ideas are illustrated with case
studies and Monte Carlo results that show its excellent performance.
