Maintenance and servicing of large construction projects are nowhere more needed than in space, where the conditions are extreme, and human technology has a short lifespan. Extravehicular activities, robotics, and autonomous systems have been useful for maintenance missions and have helped conduct groundbreaking research. Researchers at the University of Lincoln today said the E-Walker robot demonstrates a new way to handle such projects.
Advances in robotics and related systems facilitate numerous in-space services, including manufacturing, assembly, maintenance, astronomy, earth observation, and debris removal, noted the scientists. With the countless risks involved, relying only on human builders is not enough, and current technologies are becoming outdated.
“We need to introduce sustainable, futuristic technology to support the current and growing orbital ecosystem,” said Manu Nair, a Ph.D. candidate at the University of Lincoln in the U.K. He is also corresponding author of the report, which presented his team's findings in Frontiers in Robotics and AI.
“As the scale of space missions grows, there is a need for more extensive infrastructures in orbit,” Nair said. “Assembly missions in space would hold one of the key responsibilities in meeting the increasing demand.”
In their paper, Nair and his colleagues introduced a dexterous walking robot that can be used for in orbital assembly missions. As a use case, the researchers tested the robot for the assembly of a 25-m (82-ft.) Large Aperture Space Telescope (LAST).
Why telescopes are assembled in orbit
Ever since the launch of the Hubble Space Telescope and its successor, the James Webb Space Telescope (see video below), the space community has been continuously moving towards deploying newer and larger telescopes with larger apertures—the diameter of the light-collecting region.
Assembling telescopes such as LAST on Earth is not possible because of the limited size of current launch vehicles. That is why larger telescopes ideally need to be assembled in orbit.
“The prospect of in-orbit commissioning of a LAST has fueled scientific and commercial interests in deep-space astronomy and Earth observation,” said Nair.
To assemble a telescope of that size in space, the right tools are necessary.
“Although conventional space-walking robotic candidates are dexterous, they are constrained in maneuverability,” Nair observed. “Therefore, it is significant for future in-orbit walking robot designs to incorporate mobility features to offer access to a much larger workspace without compromizing the dexterity.”
E-Walker robot offers versatility
The University of Lincoln team proposed a seven degrees-of-freedom (DoF), fully dexterous, end-over-end walking robot, or E-Walker. The limbed system uses the Robot Operating System (ROS) and can move along a surface to different locations to perform tasks.
The researchers conducted an in-depth design engineering exercise to test the robot for its capabilities to efficiently assemble a 25 m LAST in orbit. They compared the robot to the existing Canadarm2 and the European Robotic Arm on the International Space Station.
In addition, the team developed a scaled-down prototype for Earth-analog testing and performed another design engineering exercise.
“Our analysis shows that the proposed innovative E-Walker design proves to be versatile and an ideal candidate for future in-orbit missions,” said Nair. “The E-Walker would be able to extend the life cycle of a mission by carrying out routine maintenance and servicing missions post-assembly in space.”
“The analysis of the scaled-down prototype identifies it to also be an ideal candidate for servicing, maintenance, and assembly operations on Earth, such as carrying out regular maintenance checks on wind turbines,” he explained.
Much remains to be explored, acknowledged the team. Its research was limited to the design engineering analysis of a full-scale and prototype model of the E-Walker.
“The E-Walker prototyping work is now in progress at the University of Lincoln; therefore, the experimental verification and validation will be published separately,” said Nair.
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