"The 24th was technically the best date to do the (space walk)," said Mike Suffredini, a space station manager at NASA's Johnson Space Center near Houston, Texas.
US astronaut Michael Fincke and Russian cosmonaut Gennady Padalka, who arrived at the space station April 21, will repair one of four gyroscopes controlling the station's orientation as it orbits Earth.
The crew will replace a circuit breaker that failed and cut power from the gyroscope, NASA says on its website. A second gyroscope is also broken, but the station can work on the two remaining ones, it said.
The space walk will last from 2150 GMT to 0350 GMT, said John Curry, director of ISS Extravehicular Activity.
"The crew will be (Wednesday) starting to do some of the deconfiguration activities to get prepared," Curry said.
The space walk was originally scheduled for June 16, but it was delayed to avoid possible communication problems resulting from the launch of a satellite from Russia.