In a 2-day hackathon between Imperial College and Oxford University, sponsored by Spacebit, a winning entry of a streamlined deployment system was devised for Spacebit’s Asagumo lunar rover. Focused on simplicity and efficiency, the mechanism uses a trapdoor to release the rover, which then slides down Kevlar ropes, slowing its descent. Triggered remotely upon landing, this system ensures a controlled descent onto the lunar surface, optimizing safety and efficiency for the mission.

Project Context

Spacebit is a British company focused on developing space robotics technology. They developed the Asagumo robot, a spider-like rover and plan to send it on a mission to the moon. For this mission our team designed a deployment system for the lunar rover once the launcher lands on the moon. This aims to safely lower the Asagumo down from a height of 0.8 meters onto the lunar surface. If the robot was to be deployed and free fall from this height, even with the moons lower gravity it could cause impact damage to the rover, as well as landing in an undesired orientation. For us simplicity is key, designing a low-cost lightweight and highly automated mechanism with one single trigger.

Deployment Box Design

From the initial deploy box conditions the team decided to use a trapdoor mechanism to open the bottom face of the deployer box. Then it was decided that the rover should slide down the ropes to slow down its descent. Inspired by a rappel rack, the rover was designed to slide around two cylinders as it fell. The simplicity of the total mechanism then meant the size of the deployer box could be decreased from 20 by 25 centimetres to 15.5 by 15 centimetres. The size of the box will also be the frame with a thermal MLI foil covering it instead of solid to reduce weight. This system will be triggered by a signal sent from the command centre to the lander when it lands on the moon. This will open the bottom face of the deployer box through a trapdoor mechanism controlled by two small motors, then gravity will cause the river to descend by sliding down four Kevlar ropes the ropes are 65 centimetres long and have a diameter of three millimetres so have a total mass of 25 grams. With a breaking strength of 300 newtons, it will be able to withstand the weight of the rover on the lunar surface.

Asagumo Rover Modifications

The rover will have four sets of two aluminium rods attached to its side faces. The horizontal orientation of the rods will generate friction between them and the rope resulting in a slower descent of the rover. This impedes the acceleration by 90% and its impact velocity by around 66% this could be reduced even further with additional rods in the mechanism however this means added weight and cost. As the rover descends at low speed it can extend its legs to prepare for impact with the ground. When it reaches the end of the 65 centimetre ropes it will pass and free fall to the lunar surface for approximately 10 centimetres.

Conclusion

With a focus on simplicity, the devised mechanism employs a trapdoor system and Kevlar ropes passing through a rappel-rack to ensure a controlled descent onto the lunar surface. This approach not only optimizes safety but also enhances the overall efficiency of the mission. As humanity continues to explore space, innovative and collaborative solutions pave the way for future advancements in space exploration.