NASA astronaut Peggy Whitson is pictured with an Orbital ATK Cygnus spacecraft (left) during a May 12, 2017 spacewalk outside the International Space Station. Whitson, the station's commander, and fellow NASA astronaut Jack Fischer will conduct a repair spacewalk on Tuesday, May 23.<\/p>\n
CAPE CANAVERAL, Fla. NASA astronauts will take an unplanned spacewalk Tuesday (May 23) to replace a failed data relay box outside of theInternational Space Station, restoring critical redundancy to the orbiting outpost, agency officials said Sunday (May 21). <\/p>\n
The failed device, known as a multiplexer\/demultiplexer, or MDM, was installed on March 30 during a spacewalk by NASA astronautsPeggy Whitson, now the station's commander, and then-flight engineer Shane Kimbrough, who returned to Earth last month. Whitson will perform Tuesday's spacewalk repair with fellowNASA astronaut Jack Fischer who arrived at the orbiting laboratory in April. [Watch: Whitson and Fischer Play Zero-G Water Ping Pong] <\/p>\n
The MDM, one of two located on the outside of the station's S0 segment of the station's backbone-like main truss, controls exterior U.S. systems, including solar arrays, cooling loops, radiators and other equipment. <\/p>\n
The upgraded MDM failed on Saturday (May 20), NASA officialssaid in a statement, adding that the crew was never in any danger. <\/p>\n
\"The cause of the MDM failure is not known,\" the statement said. <\/p>\n
After the failure, the station switched over to the spare MDM, but NASA wants to restore redundancy as quickly as possible. <\/p>\n
Station program managers met on Sunday to assess troubleshooting efforts and decided to replace the failed unit with a spare. <\/p>\n
Working inside the station, Whitson spent Sunday assembling and testing a new MDM, which will be installed during a two-hour spacewalk Tuesday. The unit measures 10.5- by 14.9- by 16.4 inches (27- by 38- by 42 centimeters) and weighs 51 lbs. (23 kilograms.) <\/p>\n
Whitson and Fischerconducted the station's last spacewalk on May 12. The stations current crew also includes two Russian cosmonauts and French astronaut Thomas Pesquet of the European Space Agency. <\/p>\n
The MDM failure and replacement is not expected to impact next week's launch of aSpaceX Dragon cargo ship to the station, NASA spokesman Dan Huot said. <\/p>\n
Launch of a Falcon 9 rocket with the Dragon freighter currently is targeted for June 1. <\/p>\n
Tuesday's spacewalk is scheduled to begin at 8 a.m. EDT (1200 GMT). NASA's live webcast coverage will begin at 6:30 a.m. EDT (1030 GMT).You can watch the webcast live here, courtesy ofNASA TV. <\/p>\n
Irene Klotz can be reached on Twitter at @free_space. Follow us@Spacedotcom,FacebookandGoogle+. Original article onSpace.com. <\/p>\n
<\/p>\n
View post: NASA astronaut Peggy Whitson is pictured with an Orbital ATK Cygnus spacecraft (left) during a May 12, 2017 spacewalk outside the International Space Station. Whitson, the station's commander, and fellow NASA astronaut Jack Fischer will conduct a repair spacewalk on Tuesday, May 23. Continue reading
\nSpace Station Astronauts to Take Surprise Spacewalk Tuesday to Replace Failed Computer Relay - Space.com<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"