(Source: NASA)

The Mobile Servicing System (MSS) is a robotic system used for space station assembly and maintenance: moving equipment and supplies around the station, supporting astronauts working in space, and servicing instruments and other payloads attached to the space station. The MSS includes facilities on Earth for mission support and astronaut training. Built at a cost of U.S. $896 million (over 20 years)

The MSS is composed of three separate components:

1. Canadarm2, also known by its technical name, the Space Station Remote Manipulator System (SSRMS). The SSRMS as part of Canada's contribution to the ISS. The next generation Canadarm is a bigger, better, smarter version of the Space Shuttle's robotic arm. It is 17.6 meters (57.7 feet) long when fully extended and has seven motorized joints. This arm is capable of handling large payloads and assisting with docking the space shuttle. The Space Station Remote Manipulator System, or SSRMS, is self-relocatable with a Latching End Effector, so it can be attached to complementary ports spread throughout the station's exterior surfaces.

The SSRMS is comprised of long composite booms made from PEEK/IM7 (PolyEtherEtherKetone / Carbon fibre) composite, which are manufactured by FRE Composites Inc.

2. The Special Purpose Dexterous Manipulator (SPDM), a smaller, highly advanced detachable two-armed robot that can be placed on the end of the space arm. It will perform sophisticated operations including installing and removing small payloads, such as batteries, power supplies and computers.

This robot can also handle tools, such as specialized wrenches and socket extensions, for delicate maintenance and servicing tasks, provide power and data connectivity to payloads, as well as manipulate, remove and inspect scientific payloads. The SPDM is also equipped with lights, video, equipment, a tool platform and four tool holders.

This robot will be able to touch and feel much like humans. It can sense various forces and moments on a payload and, in response, can automatically compensate to ensure payloads are moved smoothly. The SPDM will be controlled by the ISS crew via the Robotic Workstation, and can perform a great many of the tasks that would otherwise require an astronaut to perform during spacewalks.

3. The final component is the Mobile Remote Servicer Base System (MBS), a movable platform for Canadarm2and the SPDM that slides along rails on the Space Station's main truss structure to transport Canadarm2 to various points on the Station, providing lateral mobility for the Canadarm as it traverses the main trusses. It is equipped with four Power Data Grapple Fixtures and a Latching End Effector to hold payloads (or alternatively, the SPDM).

(Source: NASA)

(Source: NASA)

Technical Detail Remote Manipulator System Dexterous Manipulator Base System Arm Length 17.6 meters (57.7 feet) 3.5 meters (11.48 feet) linear stroke 5.7 meters x 4.5 meters x 2.9 meters (18.7 feet x 14.76 feet x 9.5 feet) Mass (approx.) 1,800 kilograms (3,968 pounds) 1,662 kilograms (3,664 pounds) 1,450 kilograms (3,196.7 pounds) Mass Handling/Transportation Capacity 116,000 kilograms (255,736 pounds) 600 kilograms (1,322.77 pounds) 20,900 kilograms (46,076.61 pounds) Degrees of Freedom 7 15 Fixed Peak Power (operational) 2,000 W 2,000 W 825 W Avg. Power (keep alive) 435 W 600 W 365 W Applied Tip Load Range 0-1,000 N 0-111 N N/A Stopping Distance (under max. load) 0.6 meters (1.96 feet) 0.15 meters (5.9 inches) N/A

(Source: NASA)