NASA astronauts wrap up second spacewalk

Washington: NASA astronauts Scott Kelly and Kjell Lindgren ended their second spacewalk ​outside the International Space Station (ISS) at 2:10 p.m. EST with the repressurization of the US Quest airlock. 

The astronauts restored the port truss (P6) ammonia cooling system to its original configuration, the main task for Friday’s spacewalk. They also returned ammonia to the desired levels in both the prime and back-up systems.

The pair encountered leaking ammonia and minor glove damage while performing their spacewalk.

Lindgren reported intermittent flakes of toxic ammonia while making connections in a cooling line. However, he assured Mission Control it appeared to be just a small leak.

The 7 hour and 48 minute spacewalk was the second for both astronauts, and the 190th in support of assembly and maintenance of the orbiting laboratory. 

The duo switched their spacesuits to battery power at 6:22 a.m. EST, signifying the start of Friday’s spacewalk, which was planned for 6 hours and 30 minutes initially.

In 2012, NASA detected a major leak in the ammonia cooling system. Astronauts replaced the ammonia pump on the station's truss in May 2013.

Friday's spacewalk is the 190th in support of the International Space Station, which just marked 15 continuous years of human habitation.

Kelly and Lindgren took their first spacewalk on October 28, during which they performed a number of tasks.