The space shuttle Atlantis, fresh from a fiery launch, was in hot pursuit of the international space station on Saturday, but will not catch it until Sunday. A slight concern about an exposed area in the shuttle's delicate heat-protection system arose overnight when engineers examined photos taken by the shuttle's crew after launch. The photo showed a small exposed area in thermal blankets on the left side of the shuttle near the thrusters Atlantis uses to move about in orbit, said NASA spokesman Louis Parker. That area is not a usual focus for potential heat problems when the shuttle returns to earth, but normal day-after-launch inspections will assess it, Parker said. "There's not a whole lot of concerns just yet," Parker said Saturday morning.