NASA astronauts will perform an emergency spacewalk to replace a faulty relay box outside the ISS. During the spacewalk, new antennas will also be installed to enhance wireless communications.
Two astronauts arrived at the International Space Station (ISS) aboard Soyuz rocket. The two astronauts will join Expedition 51 crew members on board.
Yurchikin and Fischer will return to Earth on June 2 after a 135-day mission, and filling the third seat of their flight is astronaut Whitson. Soyuz MS-04 is the 50th Soyuz spacecraft launched to the ISS.