Cosmonauts Sergey Prokopyev and Dmitri Petelin were dressed in spacesuits, with the airlock depressurized, when flight controllers told them to standby while the leak in a Soyuz spacecraft was investigated.Public affairs officer Rob Navias, who was commentating on the spacewalk for NASA Television, characterized the spacecraft as leaking "fairly substantially."Video of the coolant leak showed particles streaming continuously from the Soyuz, a rather remarkable sight.At no time were any of the crew members on the space station in danger, including Prokopyev and Petelin, their fellow cosmonaut Anna Kikina; NASA astronauts Frank Rubio, Nicole Mann, and Josh Cassada; and Japanese astronaut Koichi Wakata.Much of the ammonia would probably boil off the surface of the hardware over time, but it will certainly complicate operations as the US space agency works toward conducting a spacewalk of its own on December 19 to install new solar arrays."