The International Space Station (ISS) is the largest and most ambitious space program since the Apollo moon landings and the largest scientific joint effort among nations in history. The International Space Station partners a global team led by NASA. Countries participating in the program include the United States, Canada, Japan, Russia, Brazil and a consortium of European communities under the flag of the European Space Agency. Each of the international partners is providing key elements to the program. The first components of the station were placed in orbit in late 1998. 

The space station will provide unique laboratories to conduct research in fields such as astronomy, life sciences and materials, as well as locations to assemble satellites and space platforms too large and fragile to launch directly from Earth. The advanced technologies being used to construct the station will find applications in many industries on earth. 

Under government contract to the Canadian Space Agency, MDA, with the help of a Canada-wide industrial team, developed the robotic systems that represent Canada's contribution to the International Space Station. The Mobile Servicing System (MSS) provides the International Space Station with sophisticated space-based robotics to assemble, transport, and maintain payloads in orbit, as well as help build and maintain the space station itself. 

The MSS comprises the following elements: 

• Canadarm2 - Space Station Remote Manipulator System (SSRMS) - a 17-meter long arm with seven motorized joints capable of handling large payloads and assisting with docking of the 100,000-kg shuttle.
• Special Purpose Dexterous Manipulator (SPDM)  - a two armed robot capable of handling many of the servicing and assembly tasks currently performed by astronauts on space walks.
• The Mobile Base (MBS) - a work platform and storage area for SSRMS, SPDM, various tools and payloads.
• Astronauts inside the space station operate the SSRMS and SPDM robotics from the Robotic Workstation (the RWS is an element related to the MSS and is being supplied under separate contract to NASA).

MSS System Design

The Space Station itself will be built around pre-integrated truss segments which will form the backbone to which all other systems and modules will be attached. The truss segments will be equipped with rails on which an element called the Mobile Transporter will ride, carrying the Mobile Base System (MBS). Normally the Canadarm2 will be attached to the MBS, as will the Special Purpose Dexterous Manipulator (SPDM). However, the Canadarm2 has been designed in such a manner that a Latching End Effector is mounted at each end of the arm, thus allowing the arm to "walk", hand over hand, around the entire space station. The range of accessibility of the Canadarm2 will be limited only by the number of Power Data Grapple Fixtures (PDGF) installed on the station.

The SPDM is an extremely advanced, highly dexterous robot with two arms that will perform a great many of the tasks that would otherwise require an astronaut to perform in Extra-Vehicular Activity. The SPDM can operate from the Mobile Base System or can be "grappled" by the free end of the Canadarm2 and maneuvered into position.