CAPE CANAVERAL, Fla. (AP) — In a rare scare, astronauts fled the American side of the International Space Station on Wednesday after an alarm indicated a possible toxic leak. NASA later said there was no leak of ammonia coolant and a computer problem likely set off the false alarm.By Wednesday afternoon, the astronauts were back in the U.S. part of the orbiting outpost. Earlier, the six crew members had huddled safely on the Russian side — once when the alarm sounded and again following an initial all-clear.“Hey everybody, thanks for your concern,” Italian astronaut Samantha Cristoforetti said via Twitter.