NASA is preparing to conduct a spacewalk on Tuesday, May 23, to replace a computer component mounted on the International Space Station that failed Saturday morning. The multiplexer-demultiplexer (MDM) is one of two redundant data relay boxes used to control the solar array systems, radiators, cooling loops, and other hardware aboard the station. The backup MDM is functioning properly and the astronauts on the ISS are in no danger, according to a press release from NASA.
Expedition 51 Commander Peggy Whitson and Flight Engineer Jack Fischer, both of NASA, will suit up and venture out around 8 a.m. EDT on Tuesday. The spacewalk to replace the data relay box is expected to take about two hours. NASA added an additional task for Fischer to install a pair of wireless communication antennas while Whitson replaces the box.
Whitson assembled and tested a spare data relay box on Sunday morning, and she reported that the new box is functional and ready to be installed as a replacement. Along with Expedition 50 Commander Shane Kimbrough, Whitson helped install the MDM that recently failed during a spacewalk that was carried out March 30.
The last emergency spacewalk on the ISS took place in December 2015 when two astronauts ventured outside to release seized brakes on one of the station's robotic arms. Tuesday's spacewalk will be Whitson's tenth and Fischer's second trip outside the ISS. Coverage of the mission is expected to begin at 6:30 a.m. EDT on NASA TV.
Jay Bennett is the associate editor of PopularMechanics.com. He has also written for Smithsonian, Popular Science and Outside Magazine.
