 ABC's Brian Clark, the TSA, expects to screen more than 3 million people today. Your chances are greater of getting hit by lightning than space junk, but the FAA says that probability gap is shrinking. Just this year, space debris has been found in Canada, North Carolina, and Florida, where a Naples homeowner has demanded payment from NASA for damage caused to his home. Dr. Samantha Lawler teaches astronomy at the University of Regina in Saskatchewan. She's worried.