With the Russian-built Zarya Control Module orbiting about 16,000 nautical miles in front of Endeavour, Mission Specialist Nancy Currie successfully checked out the 50-foot-long robot arm she will use to grapple the Unity connecting module late this afternoon. Currie will lift Unity out of the shuttle's cargo bay and carefully position it perpendicular to the shuttle, ready for latching to the Orbiter Docking System in the front portion of the bay. Currie moved the robot arm around the cargo bay last night, offering an extensive television survey of Unity and its pressurized mating adapters.
Astronauts Jerry Ross and Jim Newman successfully tested all three of the space suits carried on Endeavour. They will use two of the suits during three space walks to hook up electrical cables and other connectors between Unity and Zarya. With the help of Pilot Rick Sturckow, the space walk choreographer on the flight, Ross and Newman also checked out a pair of jet-powered backpacks they will wear during the space walks as a precaution in the event they become untethered during their work in the void of space.
Endeavour's cabin pressure also was lowered to 10.2 pounds per square inch to set the stage for the space walks, which begin late Monday afternoon.
Commander Bob Cabana monitored the work as the astronauts extended the outer ring of the docking system on which Unity will be mounted later today, and Russian Cosmonaut Sergei Krikalev checked out other gear that will be used during Sunday's rendezvous to catch Zarya for its mating to Unity.
Endeavour is orbiting the Earth at an altitude of 202 statute miles, preparing to climb to about 240 statute miles for the rendezvous Sunday with Zarya. All of Endeavour's systems are functioning normally.
The astronauts are scheduled to be awakened at 1:36 p.m. Central time to begin their third day of work on orbit.