Reflecting the international cooperation involved in building the largest space complex in history, Commander Bob Cabana and Russian Cosmonaut Sergei Krikalev opened the hatch to the U.S.-built Unity connecting module at 1:54 p.m. Central time Thursday and floated into the new station together.
The rest of the crew followed and began turning on lights and unstowing gear in the roomy hub to which other modules will be connected in the future. Each passageway within Unity was marked by a sign leading the way into tunnels to which new modules will be connected.
About an hour later, at 3:12 p.m., Cabana and Krikalev opened the hatch to the Russian-built Zarya control module, which will be the nerve center for the station in its embryonic stage. Joined by Pilot Rick Sturckow and Mission Specialists Jerry Ross, Jim Newman and Nancy Currie, Cabana and Krikalev hailed the historic entrance into the International Space Station and said the hatch opening signified the start of a new era in space exploration.
Ross and Newman went right to work in Unity, completing the assembly of an early S-band communications system that will allow flight controllers in Houston to send commands to Unity's systems and to keep tabs on the health of the station with a more extensive communications capability than exists through Russian ground stations. The astronauts also conducted a successful test of the videoconferencing capability of the early communications system, which will be used by the first crew to permanently occupy the station in January 2000. Newman downlinked greetings to controllers in the station flight control room in Houston and to astronaut Bill Shepherd, who will command the first crew and live aboard the station with Krikalev and Cosmonaut Yuri Gidzenko.
Krikalev and Currie replaced a faulty unit in Zarya which controlled the discharging of stored energy from one of the module's six batteries. The battery had not been working properly in its automatic configuration, but the new unit was functioning normally shortly after it was installed.
The astronauts also unstowed hardware and logistical supplies stored behind panels in Zarya, relocating the items for use by the shuttle crew that will visit the station in May and Shepherd's expedition crew. Late this afternoon, the astronauts will complete their initial outfitting of the station.
The hatches to Zarya and Unity will be closed before Endeavour undocks from the new station Sunday, leaving the new complex to orbit the Earth unpiloted.
The astronauts begin an eight-hour sleep period at 2:36 a.m. Central time this morning and will be awakened at 10:36 a.m. to begin their ninth of day in orbit.
Endeavour and the International Space Station are circling the globe every 90 minutes at an altitude of 247 statute miles with all systems operating in excellent shape.