The head of Russian space agency Roscosmos on Tuesday praised Russia-U.S. cooperation at the International Space Station following a major coolant leak from a Soyuz crew capsule.Russian cosmonauts Sergei Prokopyev and Dmitry Petelin, as well as U.S. astronaut Frank Rubio, flew from Kazakhstan to the ISS on a Soyuz rocket on Sept. 21.The coolant leak reported on Thursday forced the last-minute cancellation of a routine spacewalk by the two Russians, and could potentially impact the return flight of the three crew members to Earth.Roscosmos said on Monday that, following an initial temperature spike inside the Soyuz capsule, it had "stabilized" at around 30 degrees Celsius.It added that the cause of the leak was being established and that a special commission would determine whether the capsule could be used to bring the astronauts back to Earth."