Issue 40 Unmanned Systems Technology October/November 2021 ANYbotics ANYmal D l AI systems focus l Aquatic Drones Phoenix 5 l Space vehicles insight l Sky Eye Rapier X-25 l FlyingBasket FB3 l GCS focus l AUVSI Xponential 2021

52 W hile unmanned systems built for operations on Earth come in a range of designs and sizes, their intended applications increasingly fall into a few discrete areas, such as logistics, mapping and inspection jobs. Space vehicles, however, operate on new frontiers and provide new services that are very different from those for terrestrial systems. Off-world geological and scientific research is uncovering secrets about the Solar System and the nature of the planets, while other spacecraft are to lay the ‘groundwork’ for safe, sustainable economic infrastructure, from Earth’s orbit and out towards our extraterrestrial neighbours. Orbital missions The growing number of human-made satellites and vehicles in Earth’s orbit is driving up the amount of orbital debris. If space junk is allowed to proliferate unchecked, our planet will be at risk of Kessler syndrome, a chain reaction of collisions that increases the number of particles of debris circling the planet at high speed, making it near-impossible to navigate Earth’s orbit without being struck. The need to address this worrying – and growing – possibility is driving the market for solutions to it. One of these is the Space Tug being developed by Scottish company Skyrora. The Space Tug is a 3.1 m-long, 1.9 m-wide unmanned spacecraft designed to be launched into different levels of Earth’s orbit by a three-stage rocket. Debris and obsolete satellites can be removed in one of two ways: by de-orbiting them back towards the Earth, or moving them into an orbital plane designated for further disposal steps. The system is powered by four solar arrays and propelled by a largely additively manufactured main engine, capable of producing up to 3.5 kN of thrust and which can be fuelled by Ecosene, a chemical made from otherwise unrecyclable plastics. The engine can be re-fired multiple times while in orbit, enabling the craft to conduct multiple missions per trip. The Space Tug is also being put Rory Jackson gives a round-up of the latest applications and innovations in off-world unmanned systems To the outer Skyrora’s Space Tug is being developed for repeatable missions such as de-orbiting space junk or inspecting orbital structures (Courtesy of Skyrora) October/November 2021 | Unmanned Systems Technology