Washington, July 23 (DPA) Problems with a spacesuit has caused NASA to cut short a spacewalk outside the International Space Station.

Problems with a system that removes carbon dioxide from the air in astronaut Chris Cassidy's spacesuit caused mission control to end the spacewalk at 2031 GMT Wednesday after five hours and 59 minutes. Carbon dioxide levels were beginning to rise in his suit, but he was not in any imminent danger, NASA said. The spacewalk was to have lasted about six and a half hours.

Cassidy and fellow US astronaut Dave Wolf spent the spacewalk changing batteries on one of the station's solar panels. Because of the spacesuit problems they were able to swap out just two of four batteries that were to be exchanged during the spacewalk. A third old battery was removed, but they did not have time to install a new one when the spacewalk was cut short.

Each solar panel on the station has six batteries, and the panels' other batteries will be swapped during a spacewalk later in the mission.