If the ISS was ever to expand further and faster, additional robotic arms would be needed than were available from a visiting Space Shuttle Orbiter, or when an Orbiter was not docked with the station.

STS-100, launched on April 19, 2001, would deliver the first robotic arm assembly for the station, called the Canadarm. Like the Orbiter’s remote manipulator arm, the Canadarm was designed by the Canadian Space Agency.

In addition to the new arm, Shuttle Endeavour would carry the second of two Multipurpose Logistics Modules, Raffaello.

Shuttle Endeavour arrived on station to begin one of the station’s most complex spacewalks to-date.

STS-100 Approach
Endeavour on approach. The silver cylinder of the Raffaello MPLM rests in the aft of the payload bay. A pallet containing Canadarm2 sits closer to forward. (NASA video capture)

As with prior Orbiter arrivals, the station and Shuttle crews would not personally meet for a couple of days until the spacewalks were complete since there were pressure differentials between the Orbiter’s docking port (which also included its outer airlock) and the station itself. After some items were left in a compartment for the station crew to pick up, it was time to get the Canadarm moved–not an easy job.

The easier part was using Endeavour’s robotic arm to remove the pallet containing the station’s robotic arm from the Shuttle’s payload bay to a spot adjacent to the Destiny module.

The first task in the first of two spacewalks by astronauts Chris Hadfield and Scott Parazynski was to install a UHF communications antenna, which would improve overall station-to-ground and EVA communications.

Getting the arm out first required the removal of a series of arrow-like bolts that held the arm fast to the pallet. Once that was done, Hadfield, standing atop the Orbiter’s arm on a foot platform, lifted one-half of the arm, folded into several “elbows.” Hadfield had to exert over 140 pounds of dead-lift power to unfold and unfurl the initial segments.

After several stubborn bolts were mechanically and manually ratcheted into joints that were meant to stay fixed in place to form the booms, the primary assembly work on the arm was complete.

After the Shuttle and station crews met and exchanged pleasantries and gifts, it was time to get the Raffaello MPLM in place, using the Orbiter’s robotic arm, to unload additional supplies of food, clothing, water, experiments, and to exchange trash and unneeded materials for return to earth.

There was still the matter of moving Canadarm2 to its permanent home.

Under control of station crews, Canadarm2 made its first move like a centipede, attaching one of its two end-effectors (hands) to the side of Destiny., not quite leaving the cargo pallet where it was carried and which provided temporary electrical power.

For Canadarm2 to receive station power, another spacewalk commenced to route data and power lines along the laboratory and the Unity node, where the arm would be attached for the time being.

Canadarm2’s first job was to return its cargo pallet back to Endeavour.

STS-100 arm exch
Canadarm2, left and background, hands off the pallet to the Orbiter remote manipulator arm, right-center and foreground. (NASA video capture)

Endeavour gave the ISS a small boost in altitude before it departed the station. The new arm gave the ISS quite a different look.

STS-100 departure
The ISS with its new robotic arm. (NASA video capture)

Shuttle Atlantis would make a visit in three months time with a new airlock that would avoid future delays in Shuttle and station crews from meeting each other due to atmospheric pressure differences required for Orbiter spacewalks.

Next: Assembly 7A.

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