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48 Insight | Space vehicles swarms of these UGVs to discover and develop resources around which industry infrastructure can be planned and built. Elsewhere in Japan, NASA has teamed up with the Japan Aerospace Exploration Agency (JAXA) and Toyota to develop Toyota’s self-driving lunar rover. The rover, unveiled in March last year, is undergoing continued development from its initial concept, which laid out plans for a 6 x 5.2 x 3.8 m six-wheeled electric vehicle with a maximum range of about 10,000 km. It will house a pressurised 13 m 2 internal environment for two astronauts to live and work in, and it will be recharged by a combination of Toyota’s hydrogen fuel cell technology and retractable solar panels. While contributing to and collaborating with JAXA’s and Toyota’s work, however, NASA also intends to continue development of its own (unpressurised) lunar rover for its planned 2024 return to the Moon, as the Toyota-JAXA rover is not due to be ready before 2029. Mars The Mars 2020 Perseverance rover mission successfully launched from Cape Canaveral on July 30 this year, and is on track to land on February 18 next year. Carried into space by an Atlas V-541 rocket, the mission involves two unmanned systems intended to survey for signs of past habitability and lifeforms on Mars. The first is the Perseverance UGV, which is carrying a payload of seven key research instruments. These include stereoscopic EO/VNIR cameras with 3.6x zooms – a notable upgrade over the Curiosity rover, which had no zooming capability. It also has a ground-penetrating radar for producing images of ground structural layers and densities, as well as (potentially) meteorites, underground water and ice down to 10 m, along with other sensor sets for measuring and defining Mars’ atmospheric and mineral content. Perseverance will also be used to collect samples of rock and soil (potentially to be stored and brought back to Earth in a future mission), and test the feasibility of producing oxygen from the carbon dioxide in the Martian atmosphere, for use in fuel, life support or other applications. The samples will be collected using a drill installed on the vehicle, while the CO 2 experiment will use a solid-oxide electrolysis cell to split the collected carbon dioxide into oxygen and carbon monoxide. The rover is powered by a thermoelectric generator co-developed with Teledyne Energy Systems and Aerojet Rocketdyne. It will produce 110 W after the UGV is deployed, with some minimal decrease over the mission’s duration. That power will drive the 1025 kg UGV’s four wheels, which have been redesigned to be stronger than those on Curiosity, which sustained damage during its mission. Also on the Atlas V is the 1.8 kg Ingenuity helicopter UAV, which has been installed in the undercarriage of Perseverance and is poised to be the first aircraft flown in the atmosphere of a planet other than Earth’s. Although long-range exploration and aerial surveys of the Martian surface are the eventual goals of the mission, this first Ingenuity is intended primarily as a trial, to see how it handles in the Martian atmosphere and how future variants could be improved. Engineering a helicopter to fly in the Martian atmosphere requires thrust with extremely high power and speed relative to weight – more so than on Earth, as Mars’ atmospheric density is only about 1% that of Earth’s. To achieve lift on the Red Planet, the UAV is designed with a pair of coaxial rotors that drive two dual-bladed propellers about 121 cm in diameter. They are made from carbon composite skins and foam cores, and will spin at roughly 2400 rpm during flight. Power for the lift motors will be supplied by a battery pack in the cube- shaped fuselage. They will store up to 40 Wh, while above the rotors is a multi- junction solar panel, made and supplied by SolAero Technologies, for recharging the battery. The fuselage also contains the sensors – which include an IMU, a laser altimeter and two navigational cameras – for tracking the craft’s speed and heading. The main computer is a Qualcomm Snapdragon SoC running Linux, and it is supported during landing by four carbon composite struts. October/November 2020 | Unmanned Systems Technology The Lunar Cruiser is a self-driving six-wheeled rover, powered by hydrogen and solar panels to carry two astronauts (Courtesy of Toyota)