By default, IAI selects one asteroid for checking per "cycle" of the while GameRunning() loop. On a large map with 60 asteroids, this means by the law of averages each asteroid should be checked roughly once per second.
In AIinit() there is an inbuilt "iterations" variable. It is set to 1 by default, meaning "check one asteroid per cycle". If you wish you can increase this, which will have the effect of making IAI react faster, at the cost of CPU time.