At least two spacewalks will be necessary to ensure proper replacement of a failed cooling pump on the International Space Station (ISS), NASA said.
One of two cooling systems serving the ISS broke down late on Saturday, and the crew had shut down several pieces of equipment, including two of the station's four gyroscopes, to cut the heat generated on board, RIA Novosti reported.
According to emergency plan approved by NASA specialists on Sunday, U.S. astronauts Doug Wheelock and Tracy Caldwell Dyson will make an initial spacewalk no earlier than Thursday to replace the Pump Module and structurally bolt it into place on the external truss.
The duo will conduct an additional spacewalk two or three days later to mate fluid and electrical connections.
The space station has two spare Pump Modules on external stowage platforms.
NASA confirmed that the station was "in a stable configuration with most systems receiving cooling and many systems operating with redundancy following the installation of jumper cables from the Destiny Lab's power system overnight."
"The crew is not in any danger and is monitoring systems and relaxing on an otherwise off duty day," NASA said.
The current ISS crew comprises Russian cosmonauts Alexander Skvortsov, Mikhail Kornienko and Fedor Yurchikhin, U.S. astronauts Tracy Caldwell Dyson, Shannon Walker and Douglas Wheelock.