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carbon fibre and Kevlar are used to reduce the load on the actuators and battery pack. Integrating tailored composites early on in the development of the autonomous platform achieves the weight reductions, says Astrobotic, as well as allowing the excavator to operate at temperatures from -175 to +120 C. Thermally conductive composites are used for lightweight thermal management of sensitive components. Astrobotic has also developed a new drive system for the excavator. Instead of the traditional model of one actuator per wheel drive and one actuator per steered joint, it uses two total actuators – one per side – with torque transfer to all wheels on that side. This is a major move, says the company, as it allows larger motors to be used with lower gear reductions, dramatically reducing cycles at motor per distance and increasing cycle life by operating with a 10x torque margin. Alongside Astrobotic’s Andy rover, Peregrine will also carry a rover from Japanese team Hakuto, which recently signed up Japanese engineering firm Suzuki and the Japanese Aerospace Agency (JAXA) as sponsors. After six prototypes, the team has developed a more skeletal and lighter design for its rover. Hungarian company Puli Space Technologies will send a ‘Memory of Mankind on the Moon’ time capsule as a payload on the first flight of the Peregrine lander, and has an option to add its own rover. The capsule will hold ceramic tablets containing archival imagery and texts of up to 5 million characters per tablet, readable with a 10x magnifier. The remaining nine teams in the competition have until December 31, 2016, for their launch agreements to be verified by the organiser XPrize in order to proceed in the competition, and they will all have to launch before the end of 2017. For Astrobotic though this is just the beginning. It first developed a larger lander called Griffin, with a 4.5 m diameter, that can deliver a payload of 270 kg to the lunar surface, and the company sees this being used for the autonomous mining and excavation systems it is developing. The key challenge in excavation on other planets is the mass of a craft. High mass is costly in terms of fuel for launching and landing, but low-mass machines in low-gravity environments can produce only limited traction to move the regolith. This has led to new design approaches. Astrobotic’s low-mass autonomous excavator for example combines a bucket wheel, a high-volume dump bed and is made from composite materials. The bucket wheel keeps excavation resistance low by taking only small bites of the regolith at a time, but taking a large number of these small bites repeatedly. Composites such as