Alexey Ovchinin and Ivan Vagner will leave the confines of the ISS to attach the package designed to monitor celestial X-ray sources and new electrical connector patch panels on the station's Poisk module.
Cosmonaut Alexsandr Gorbunov will operate the ISS's robotic arm from inside during the spacewalk. The spacewalk is expected to last nearly seven hours.
They are also expected to remove several experiments for disposal. The cosmonauts will relocate a control panel for the European robotic arm.
It marks the space station's 272nd spacewalk for maintenance and upgrades to the orbiting laboratory.
Ovchinin and Vagner have been living in the space station since Sept. 11 on the Soyuz MS-26 mission along with NASA astronaut Doug Pettit.