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98 PS | Robots in near-Earth space A lmost everything that humans have sent into space has been unmanned, starting with the Soviet Union’s launch of Sputnik 1 in 1957 and extending through every satellite and space probe lifted out of Earth’s gravity well since then (writes Peter Donaldson). However, the two Northrop Grumman Mission Extension Vehicle (MEV) spacecraft launched on October 9 last year and August 15 this year herald the start of something different from the Earth-centric satellites and cosmologically focused telescopes and planetary missions to which we have become accustomed. Broadly, the role of the MEVs is in- orbit robotic maintenance and support of space infrastructure. They represent a small conceptual step towards something much more ambitious – using robots to build the things we need to become a spacefaring species. Their more modest and specific purpose is to lengthen the service lives of satellites in Geostationary Equatorial Orbit, by latching on to them and using their thrusters to keep the satellites in the correct orbit and pointing in the right direction. MEV-1 has been doing that for Intelsat 901, after docking with the almost spent comms satellite on February 26. Robots scuttling in and around space stations to conduct maintenance and repair tasks form a staple of science fiction and futurism, as do those that assemble enormous structures by connecting smaller modules together in orbit. The Gateway Foundation, which promotes its vision of a large rotating wheel spaceport called the Gateway, has designed a robotic machine to assemble the structure. Called the Gateway Segment Assembly Line (GSAL), the machine will consist of a box containing automated welding equipment. The GSAL will be configured to produce square-section truss modules to form the station’s hub, then reconfigured to assemble wedge- shaped ones to form sections of the rim. Completed trusses will be assembled by smaller robots, and their external panelling will then be welded to form an airtight shell by other robots, teleoperated from the ground or in orbit by astronauts. In this and similar visions of the future, numerous other types of robot are depicted carrying tools, hovering nearby to provide multiple viewpoints of work in progress. They will act as rescue vehicles to rescue any astronauts who may have lost their tether, and to retrieve any lost tools, for example, before they can add to the amount of space debris. With more than 42,000 tracked objects in orbit, of which only about 1200 are operational satellites, the problem of space debris is already recognised. The fear is that with a ‘business as usual’ launch rate and no mitigation, collisions between debris could eventually create a runaway cascade that could destroy every human-made object in Low Earth Orbit and render access to space essentially impossible. This scenario is known as Kessler syndrome, after NASA scientist Donald Kessler who warned about it back in 1978. Robotic vehicles such as the MEVs could play a crucial role in preventing that. As well as extending the operational lives of satellites, thereby reducing the number of launches required, they could also de-orbit them to ensure that they re-enter the atmosphere and burn up. Humanity’s future in space might depend on it. Now, here’s a thing “ ” October/November 2020 | Unmanned Systems Technology The problem with space debris is that collisions between them could lead to a cascade and render access to space impossible