With the completion of the STS-92 mission, the first permanent crew of the International Space Station were ready to go aboard.

Astronaut Bill Shepherd became the second American to fly into space aboard a Russian Soyuz spacecraft, accompanied by cosmonauts Yuri Gidzenko and Sergei Krikalev, as the Expedition 1 crew, on November 2, 2000.


With the manned shakedown of the station underway,  it was time to increase the available electrical power to the station to support later modules. STS-97, launched on November 30, 2000, would arrive with the first of the four large solar arrays on December 3.

The first of the solar arrays would generate five times more energy than the combined power of the solar arrays from Zarya and Zvezda. That array is part of the P6 Truss, which in turn was temporarily placed atop the Z1 Truss. Over future missions, the P6 Truss and array would be eventually moved to the farthest end of the port side of the Integrated Truss Structure as the ITS expanded.

For this mission, the Orbiter couldn’t dock to the Unity node’s forward Pressurized Mating Adapter. To install the truss and solar array, Endeavour parked itself on the nadir of Node 1 on Pressurized Mating Adapter #3, installed there by STS-92.

The personal greetings by Endeavour’s crew would have to wait a while, however. While the station and the Orbiter shared similar atmosphere pressures and gas types, Endeavour’s external airlock for their planned three EVAs doubled as their station’s nadir docking port with PMA #3. The Shuttle crew could perform EVAs or have access to the station interior, but not both simultaneously.

Before their construction spacewalks began, the STS-97 crew opened the hatch to the as-yet unoccupied Unity node to leave some supplies. After the hatch was closed, first Expedition crew entered Unity for the first time. The station crew left the node unoccupied before as it was little equipment to manage there and and would be useful only for now when a Shuttle was docked. Unity would have more uses by Expedition 1 in two months when a new module would arrive.

Assy 4A 0101424_orig
A NASA illustration of Shuttle Endeavour docked on Unity’s nadir (bottom) PMU, with the assembled P6 Truss and solar array installed.

For later missions, installation of additional modules would get a bit more difficult. As the station grew, the various windows aboard the Orbiter would not afford a direct view to reliably install components. The Orbiter’s Remote Manipulator System operator would have to rely on the various cameras installed along that robotic arm–but these cameras would not provide sufficient depth perception for assembly operations without an assist.

Included with the STS-97 assemblies was a system first developed by the National Research Council of Canada, with later developments through the Canadian company NEPTEC, contracted by the Canadian Space Agency.

Originally called the Orbiter Space Vision System (with many other name variations), the Advanced Space Vision System leverages the many cameras on the Orbiter’s RMS arm, inside an Orbiter’s payload bay, on the future Canadarm remote manipulator arm, and cameras that would be later installed all over the ISS exterior.

Ever see modules covered with these black dots over a square white background?

The ASVS alignment dots cover the Unity node and many other assemblies of the ISS. (NASA)

These dots form the magic of the ASVS. These dots are formed from layers of silicon dioxide (effectively, quartz) and Inconel, a super-tough metal alloy that would resist changes in temperature so they wouldn’t deform. This layering forms a very black dot with no reflectivity to light, making it suitable for the second element of ASVS.

The ASVS knows the precise location of these dots relative to the modules where they are installed, No matter what the orientation, the ASVS would be able to tell the distance and position of other modules relative to the item to be installed, allowing higher precise use of cameras to install modules without the operators being able to directly see the assembly from windows. The ASVS would play a critical role in the first interim installation of P6.

Overnight, before the first spacewalk, the crews removed the P6 Truss (the solar arrays are an element of that truss) to a hovering orientation just inside the Orbiter’s payload bay to warm up its various elements.

The next day, during the 7 hour 33 minute spacewalk, the truss was mounted atop the Z1 Truss with mechanical and some electrical connections made to lock down the truss. After removing protective covers on the two wings of the solar arrays, they were deployed. One wing of the solar array wouldn’t deploy properly at first and would require some adjustment on a later spacewalk.

There wasn’t a lot of time given for photos during the STS-97 spacewalks. Here. astronaut Carlos I. Noriega, mission specialist, waves toward his space walk partner, astronaut Joseph R. Tanner, during EVA #2 on Dec. 5, 2000. Part of the newly-deployed solar array structure extends above. (NASA)

The second spacewalk, lasting 6 hours 37 minutes, completed the electrical connections between the Z1 and P6 truss as well as to Unity. The first of the step-down voltage converters, the DDCU, was connected to provide the necessary power levels for station interior equipment as well external equipment such as the baseband signal processor, which managed the conversion of audio and video signals transmitted to and from the station. The S-Band Antenna was also reoriented with the truss, and power and data connections that would be needed for the Destiny laboratory module were prepared. In particular, PMA #2’s connections to Unity on the forward end of the node were removed to prep it for removal on the next Shuttle assembly mission.

The last spacewalk, lasting 5 hours 10 minutes, repaired the sticking solar array wing, completed additional cabling needed for exterior cameras and installed floating probes that nullified potentially dangerous electrical charges that could build up around the station’s body.

Exp1 0400386_orig
The STS-97 and Expedition 1 crews. On the front row, left to right: Astronauts Brent W. Jett, Jr., STS-97 commander; William M. Shepherd, Expedition One mission commander; and Joseph R. Tarner, STS-97 mission specialist. Second row, from the left are Cosmonaut Sergei K. Krikalev, Expedition One flight engineer; astronaut Carlos I. Noriega, STS-97 mission specialist; cosmonaut Yuri P. Gidzenko, Expedition One Soyuz commander; and Michael J. Bloomfield, STS-97 pilot. Behind them is astronaut Marc Garneau, STS-97 mission specialist representing the Canadian Space Agency (CSA). (NASA photo)

The two crews finally greeted each other face-to-face on December 8. But Endeavour’s crew visit was short. After more supplies were exchanged for trash and some equipment checks done, STS-97 departed the following day.

Looking forward at Unity and PMA#2, the new P6 truss and its solar arrays now provided substantially greater power for the ISS. (NASA)

The new station had greater power reserves. These would be put to good use when STS-98 arrived with the first long-term American space laboratory in space since Skylab in 1973.

Next: Assembly 5A.