A cooling pump on the International Space Station malfunctioned and was shut down on Wednesday. A valve on one of the two external cooling systems was shut down, but the six person crew on board are not in immediate danger, according to NASA. "It could be a serious problem, but it's not an emergency," a Johnson Space Center spokesman told the Associated Press. The crew at the station includes: two Americans, three Russians and a Japanese astronaut, all of whom were proceeding as normal, while engineers on the ground worked to investigate the cause of the failure, according to NASA. A spacewalk maybe necessary to fix the problem, according to NASA officials. The US suspended spacewalks in July, Reuters reports, after an Italian astronaut's helmet filled with water nearly causing him to drown.