This is extremely challenging as operators will have to contend with the harsh environment of space, while dealing with the complexity of satellite systems. The rewards, however, are huge – deliver satellite repair capabilities and you can enhance satellite performance as well as explore new possibilities in space exploration and communications.
All of this is uncharted territory for the space industry but here in the UK the British government has set an ambition of capturing at least 10 percent of the market by 2030.
To that end a new facility was set up in Oxfordshire and run by the Satellite Applications Catapult to accelerate innovation in the space sector by facilitating collaboration between industry and academia.
Jeremy Hadall is Robotics Development Lead at the Catapult and works in the In Orbit Servicing and Manufacturing Yard, which is a large darkroom facility created to simulate orbital environments.
The Satellite Applications Catapult is currently working on a research initiative to prolong the life of satellites and build the next generation of facilities in orbit.
“This facility is focused on in-orbit servicing, assembling and manufacturing and end of life removal from orbit,” Hadall explained. “Over the years we have launched thousands of satellites into space and there are now plenty out there that are dead and simply floating around as debris. Not only satellites but spent rocket components, bearings, bits and pieces that have come off over time and all other forms of debris that have been jettisoned off into space.
“At the beginning it wasn’t seen as an issue. Space is massive and there’s a lot of it. But over time we’ve realised that the debris orbiting the earth is dangerous and can prevent satellites from being able to function properly. In fact, just 4 per cent of what we launch returns, so the amount of waste has simply added up.
“With so much up there space craft are having to have their orbits altered, which uses both fuel and resources, and if a satellite breaks up that can have a profound impact leading to what we call the Kessler Effect, which suggests that when the amount of space debris in Low Earth Orbit (LEO) reaches a certain level, it will trigger a cascade effect in which debris will be constantly colliding and breaking up to multiply the amount of debris, creating a permanent danger for any satellite of spacecraft in orbit.
“Our aim at the Catapult is to provide active debris removal as well as the ability to service satellites in orbit to prolong their life. But that’s incredibly hard to do as nothing currently in orbit was designed to enable that.”
To test and verify
The facility, which was established in 2021 and then opened to academics and industry in 2022, uses robots to simulate how satellites would come together to carry out servicing, refuelling, assembly and manufacturing operations.
“Our role is to test and verify test technologies in an environment as near to that as experienced in space,” said Hadall.
Industrial robots have been installed to mimic propulsion systems and low gravity conditions in space. One has been mounted to the floor and another is capable of tracking across the entire yard which measures 27m by 7m.
Above: Vero cameras from Vicon provide full coverage of the entire working envelope of the robots.
“The robots are off-the-shelf industrial robots,” explained Hadall. “You would never launch one of these into space, but they give us a degree of stiffness and a degree of repeatability that we need for some of the operations that we do here in the yard. Industrial robots are extremely good at carrying out repeatable tasks accurately but tell them to move to a new position and their accuracy falls away, usually by plus or minus 10 mm, which is simply not good enough if you want to operate safely in space.
“The best way to think about these robots is not as robots - these are stand-in satellite propulsion systems. What’s important is what’s on the end of them, whether that be a vision-based navigation system, a camera, some sensors, some grappling mechanisms or another robot,” Hadall added. He continued, “Are the robots that are going to be carrying out servicing duties doing what we want them to do? The data that’s generated is taken by us and then turned into a command so that the robot moves how we want it to.”
To that end the Satellite Applications Catapult has deployed a Vicon system to help it simulate orbital operations. Vicon is a developer of tailored motion capture systems, and its cameras and software are used to map the entire environment – and to collect accurate data on the movements and performance of the robots.
“In the yard we have 33 Vicon Vero cameras. That means we’ve got full coverage of the entire working envelope of both robots, which is important because although we’re working on close proximity operations, we'll need to do that at quite a long range. Even as large as this facility is, we have to actually scale some of the models to simulate operations in space.
“Using the Vicon system allows us to map the entire environment, where the robots are and where they’re traveling to and that gives us a degree of reliability in judging how the robots are actually performing the tasks that are being asked of them.”
According to Hadall motion capture is expected to become even more integral to the In Orbit Servicing and Manufacturing Yard in the future.
“How we use motion capture is going to evolve by linking the outputs and motion capture into the robots directly. So, feeding back into the robots what the motion capture system said. The next evolution of the manufacturing field is going to be rapid.
“The most important thing this facility is working on is close proximity operations, which is getting two objects operating close to each other and almost formation-flying in orbit,” Hadall explained. “We’re aiming to fly things that are small and don’t necessarily have all of the capture mechanisms that the International Space Station, for example, would have and Vicon’s technology is playing a crucial part in enabling this.
“The operations we’re modelling are really important because they mean we can prolong the lives of satellites in orbit and remove debris or end-of-life satellites from orbit. But we can also start to build larger structures, like the next generation of space stations; or space-based solar power stations,” said Hadall.
Beyond that the research being undertaken at the yard will support and enable future space exploration.
“If we can move manufacturing into space the possibilities for both lunar and Mars exploration will be enhanced,” said Hadall. “At a small scale that’s already possible but we’re trying to do things that nobody’s ever done before. And we need to do them at a relatively high pace. So, we’re always finding out new things such as how the systems are reacting and it gives us a new insight into the whole process,” Hadall concluded.
Conclusion
The work being undertaken at the yard, along with the technology provided by Vicon, has an important role in reducing the costs and limited accessibility of manned missions for satellite servicing by developing autonomous robotic satellite servicing solutions as well as enabling manufacturing in space for remote repairs and component replacements.
While satellite maintenance presents many challenges, ranging from the cost and complexity of missions to operating in a harsh space environment with limited accessibility, the Catapult is leading the way in developing viable solutions.
