The NASA Pathfinder Web site, which is running pictures, video and audio “live from Mars,” may be approaching a popularity record. The site, which has topped 100 million “hits” since July 4, has proven so in-demand that NASA had to set up 20 “mirror” pages around the world, running the same information from different addresses, said Rich Pavlovsky of the Jet Propulsion Laboratory in Pasadena, California.