With over three decades operating the iconic Canadarm on the Space Shuttle, and Canadarm2 and Dextre on board the International Space Station, Canada has earned an enviable international reputation for excellence in advanced space robotics. The Next-Generation Canadarm project (NGC) continues the legacy of the original Canadian robotic arm by advancing research, development and prototyping of tomorrow's space-based robotic technologies.
As the international space community charts its next steps towards long-duration space exploration missions to destinations like the Moon, Mars or an asteroid, Canada is looking ahead to develop the types of robotic technologies that will be versatile and critical for such missions. This may include several types of spacecraft, from space telescopes to the vehicles that may carry humans beyond Earth's orbit. Advanced space robotics will also become increasingly important to service and maintain the extensive infrastructure of satellites near Earth to ensure the delivery of continuous and reliable services that have become part of our daily lives. With over 1100 active satellites currently operating in the near-Earth environment (many of them worth hundreds of millions of dollars), and an additional 2500 inactive satellites still orbiting around our planet, the ability to service satellites instead of replacing them could offer substantial savings for satellite providers. Furthermore, technologies developed for NGC can help address the increasingly important problem of space debris, since space robotics and specialized tools could be used to relocate or remove defunct satellites and potentially harmful objects.
Through the NGC project, Canada has designed and built terrestrial prototypes of lightweight, cost-effective robotic systems and technologies for on-orbit servicing that could extend the useful lifetime of satellites by refueling or refurbishing them, or service both manned and unmanned space infrastructure. Under contract with the Canadian Space Agency, MacDonald Dettwiler and Associates (MDA) of Brampton, Ontario, has developed four robotic systems and a mission operations station that are being used to evaluate and plan servicing operations and perform other anticipated tasks for a variety of potential future missions:
Next-Generation Large Canadarm
A prototype of a robotic arm with the same 15-metre reach as Canadarm2, but much lighter and more compact for the smaller spacecrafts of the future. Designed to operate as a test-bed for use on Earth, the Next-Generation Large Canadarm rests on air cushions that allow it a wide range of movement (six degrees of freedom). It will be used to simulate arm deployment during demanding tasks such as the capture and docking of large spacecraft for refueling.
Innovations:
- While Canadarm2 and Canadarm's segments were bolted together, the Next-Generation Large Canadarm's aluminum and composites boom sections allows them to telescope one inside the other without obstructions from mechanical fasteners. The technique was developed through a partnership between the CSA, MDA and the National Research Council of Canada.
- Since future missions may require different sizes of robots to accommodate reach and spacecraft size, the arm's scale and design are flexible. The arm's telescopic sections allow it to fold up for storage in less than 5 m3—roughly the volume of a mini-van and compatible with the design of most new space capsules and vehicles. While Canadarm2 was installed on the International Space Station manually by astronauts (including the CSA's Chris Hadfield), the Next-Generation Large Canadarm is capable of being deployed remotely without the need for a spacewalk. Also, whereas Canadarm and Canadarm2 were deployed permanently on the Space Shuttle and the International Space Station, the Next-Generation Large Canadarm segments can be retracted thanks to unique boom lock mechanisms, which give the arm structural integrity but allows it to be packed up and deployed on a different spacecraft or reused for another type of mission.
Next-Generation Small Canadarm
With a 2.58-metre reach, this smaller manipulator prototype builds on the capabilities of Dextre, the Canadian-built robotic "handyman" aboard the International Space Station. The Next Generation Small Arm test bed is a smaller, light-weight, dexterous robot with advanced electronics, software and control systems. Much like Dextre's recent successful Robotic Refueling Mission, the Next-Generation Small Canadarm was designed with a suite of tools to support the refuelling of failing satellites in space and repair or replace essential components. Outfitted with specialized tools, the Next Generation Small Arm will perform a variety of intricate tasks including: removing and installing components (orbit replaceable units), removing the protective blankets that cover satellites; cutting wires; opening and closing a satellite fuel fill/drain valve, and transfer of simulated propellant between servicer and client spacecraft.
Innovations:
- MDAhas filed three patent applications for this robotics system:
- A unique robotic servicing multi-functional tool was developed for the arm, which can accommodate multiple tool tips for various tasks and tool interfaces.
- A propellant transfer system.
- A refuelling tool to allow the robot to handle the various valves and interfaces of existing satellites.
- The compact controller cards (the electronic "brains" that control the arm's motors and joints) are about 3 to 4 times smaller than Canadarm2's, which lightens the system's overall mass while the next-generation design increases functionality and flexibility.
Proximity Operations System Testbed
This test facility consists of two industrial robotic systems that simulate the delicate, precise operations involved in bringing two moving spacecraft into close proximity (within a few metres) of each other so that a robotic arm on a servicing spacecraft could capture an ailing satellite and dock it for repairs, or where an operator may command the servicing spacecraft to dock itself to a client's spacecraft.
Innovations:
Highly representative simulation models of the client and servicer spacecraft with actual sizes, realistic lighting and camera views.
Semi-Autonomous Docking System
This system was designed to take over the close operations from the Proximity Operations System Testbed, guiding a spacecraft through a series of robotically performed procedures from initial contact to the final stages of locking two space vehicles together. It is designed to evaluate docking interaction and sensor performance.
Innovations:
While current space docking systems are controlled remotely by operators, this facility is equipped with sensors that autonomously detect successful docking and trigger the mechanisms that rigidize the connections involved in the docking of two spacecraft.
Missions Operations Station
The four components of the project are choreographed through a Missions Operations Station, a mini "Mission Control" capable of planning a servicing mission, from proximity operations through docking and servicing.
Together, the infrastructure developed for NGC forms a unique facility to test, demonstrate and develop new mission concepts and hardware, thereby promoting Canada's capabilities, know-how and readiness to participate in future space missions.
This world-class test facility will be able to demonstrate the next generation of the entire operational process involved in performing robotic missions for servicing satellites, space observatories and exploration spacecraft.
Funding
The Government of Canada invested 53.1 million in designing and building NGC.
Other NGC achievements
- Since October 2009, and over the course of the project, NGC maintained an average of 71 full-time highly skilled workers with a peak of 92 full-time equivalent persons.
- 95% of the 1.2 million parts used for NGC were made in Canada.
- 1529 engineering drawings and 604 000 source lines of software coding were generated for NGC.
- Some NGC technologies are already being applied into new (export) applications.
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