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The Mobile Servicing System

Canada’s Next Generation of Space Robotics for the International Space Station

The Mobile Servicing System (MSS) is essential to the construction of the Station, to many Station operations and to the maintenance of the Station throughout its service life.

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The Mobile Servicing System includes facilities on Earth for mission support and astronaut training. Built at a cost of $1.4 billion (over 20 years), the MSS is actually composed of three separate parts:

• Canadarm2, also known by its technical name, the Space Station Remote Manipulator System;

• 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.

• The final component is the Mobile Remote Servicer Base System, a movable platform for Canadarm2 and the SPDM that slides along rails on the Space Station’s main truss structure to transport Canadarm2 to various points on the Station. It is equipped with four Power Data Grapple Fixtures and a Latching End Effector to hold payloads (or alternatively, the SPDM).

Specifications

With the collaboration of MD Robotics, prime contractor of the MSS.

	SSRMS	SPDM	MBS
Length (metres)	17.6	3.5	5.7 x 4.5 x 2.9
Mass (approx.)	1641 kg	1662 kg	1500 kg
Mass Handling Capacity	116 000 kg	600 kg	20 900 kg
Degrees of Freedom	7	15	Fixed
Peak Power (operational)	2000 W	2000 W	825 W
Average Power (keep alive)	1200 W	600 W	365 W
Stopping Distance (Under Maximum Load)	0.6 m	0.05 m	N/D