Spacewalk planned to fix ammonia leak

WASHINGTON – Two astronauts will make a hastily planned spacewalk today to try to fix an ammonia leak in the power system of the International Space Station.

The leak in a cooling system was discovered Thursday when “snowflakes” of ammonia were seen flying away from the station.

Spacewalks are rarely done on such short notice, but the space agency wanted to check out the leak before all the ammonia escaped and also to take advantage of a spacewalking crew member who is about to return home.

Officials emphasized that the six-member crew is not in danger and the outpost has plenty of power.

Space station program manager Michael Suffredini said the chief suspect for the leak is space junk hitting a cooling tube, but he said the area had a slow small leak for many years that suddenly accelerated Thursday.

NASA hopes the leak is in a small pump box. During the six-hour spacewalk today, U.S. astronauts Chris Cassidy and Tom Marshburn will replace the 260-pound box with a nearby spare.