ISS Repairs Drag On After Stymied Spacewalk

By Mark Carreau

HOUSTON — NASA’s International Space Station program estimates at least two more spacewalks will be necessary to resolve a vexing external cooling system failure, following a grueling weekend excursion in which two astronauts were prevented from replacing a failed pump motor assembly by an ammonia leak.

The second in the series of spacewalks by Expedition 24 ...

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