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Canadarm

The technology behind the Canadarm is one of Canada’s scientific strengths! Let’s give all of the designers, scientists, and astronauts a big hand! Look at the history and technology behind these well-oiled joints.

What Is It?

The Canadarm is a 16.9 metre-long robotic arm that operates like a human arm but runs on wires and motors! Its nerves are copper wires. Its bones are graphite-fibre-reinforced tubing, and its muscles are made of electric motors. It’s operated by a computer, the "brains of the system," which also gives guidance information to the astronaut.

Getting A Grasp On How it Works

Look at your arm. It’s made up of a bunch of parts that work together. Your hand is connected to your wrist. Your wrist and elbow are separated by your forearm, and your elbow and shoulder are separated by your upper arm. All of this is covered with skin.

Now let’s look at the Canadarm. It doesn’t have a hand, but it does have what’s called an “end effector" that works like your hand—sort of.

When you want to pick up an object, you put your fingers around it and then tighten your grip. The end effector doesn’t have fingers, but it does have a wire loop that can tighten around the object onto which it needs to grasp.

The Canadarm has three joints: a shoulder, elbow and wrist joint. The shoulder joint is capable of two different movements, while the elbow can only move in one direction. The wrist joint can move in three ways. The joints have been upgraded so that they can handle more than 120,000 kg—the mass of the Shuttle! All of the joints are separated from each other with upper and lower arm booms or poles.

All of the "bones and joints" are covered with a "skin" which is a white, fitted insulated blanket. This blanket maintains the temperature of the arm so that it doesn’t get too hot from the sun or too cold while it’s in the shadow of the Earth.

Astronauts use two-hand controllers to manage the movement of the robotic arm. All of the joints can be coordinated to move together or to operate individually. A translational hand controller manages the arm’s left, right, up, down, forward and backward movements while a rotational hand controller manages the joints. The cameras and lights on the arm and in the cargo bay transmit pictures to the astronauts so they can precisely move the arm.

Elbow Room - The History Behind the Canadarm

NASA was looking for international partners to help build the Space Shuttle so they gave countries a choice in picking and choosing what parts they wanted to build. This elbow room gave Canada a space to move in! After considering all of the options, they decided to create something that would move in space: The Shuttle Remote Manipulator System, now known as the Canadarm.

Canada was given very specific instructions: build a tool that simulated the movement of a human arm that could work perfectly in the hostile space environment.

In July 1975, Spar Aerospace Ltd. (now called MacDonald Dettwiler Space and Advanced Robotics Ltd.) began designing and building the arm, but the most challenging part was testing it!

At 410 kg, the arm could not lift itself off the ground in Earth’s gravity. A special room had to be constructed with a rig that would allow it to flex its joints. A video-game-styled simulator was also built to train astronauts. The finished unit was given to NASA for the orbiter Columbia. There is now one arm on all four space shuttles.

To date, the Canadarm has performed flawlessly on more than 50 missions!

The Canadarm Lends a Hand

The Canadarm has reached up into space to grab satellites that needed repairs and to put some into orbit. It has also been used to loosen a jammed solar panel, and to knock ice off of a Shuttle’s waste water dumping vents.

Its most notable mission occurred in December 1993. The Hubble Space Telescope needed repairs so the astronauts used the arm as if it were a cherry picker! They stood on it during five space walks! It was also used to retrieve the telescope to move it into Endeavour’s cargo bay for repairs, and then to move it back out into space.

Although the technology behind the robotic arm has a number of uses, it’s just not limited to outer space! It’s used in lots of environments that are too dangerous for humans. It has been used to service nuclear power stations, to weld and repair pipelines on the ocean floor, and to clean up hazardous wastes.

Extending the Canadarm’s Capabilities

MacDonald Dettwiler (formerly known as Spar Aerospace Ltd.) and a Canada-wide team are building on the Canadarm technology. The goal is to create the Mobile Servicing System (MSS)—robotic technology to help build and maintain the International Space Station (ISS). The MSS will reduce the amount of time that astronauts and cosmonauts have to spend in the hostile space environment.

The MSS will be made of four parts:

1. Robotic Workstations

   This will allow astronauts to control the robotic functions of this system from the pressurized environment of the ISS.

2. Space Station Remote Manipulator System (SSRMS)

   This is a 16.9-meter-long second generation Canadarm. Unlike its predecessor, the SSRMS has seven joints and therefore a greater degree of freedom of movement. It will even be able to "walk" over the length of the Station like an inchworm —or a Slinky. Neet!

3. Special Purpose Dexterous Manipulator (SPDM)

   This is a two-armed robot that will perform very delicate assembly work and servicing tasks.

4. Mobile Base System (MBS)

   This is a work platform and storage area that’s mounted onto the Space Station that can move from one end of the truss to the other.

In April 2001, STS-100 will mark two major moments in the history of Canada's Space Program. First, Canadian Space Agency Astronaut Chris Hadfield will install the huge new Canadian robotic arm on the Space Station (SSRMS). This is a major element of the MSS. Second, Chris will be the first Canadian to perform a space walk. He has been assigned the role of Lead Space walker! Wow!