NASA and Russia's space agency canceled a spacewalk by two Russian cosmonauts just as they were preparing to exit the International Space Station late Wednesday because of an apparent coolant leak from an attached space capsule.
NASA's Johnson Space Center said Sergey Prokopyev and Dmitri Petelin were not in danger, nor were other astronauts on the space station. The cosmonauts had donned spacesuits and depressurized an airlock when the leak appeared on a live video feed.
