Author: William Easdown -
Since October my team of eight students from Bath SpaceSoc, Aqua Lunae, has been working on a small lunar rover engineering model for the national UKSEDS Lunar Rover Competition. The competition challenges teams from UK universities to design and build a small rover to collect a dry ice sample from within a crater in a simulated lunar environment. It aims to teach participants about spacecraft engineering and give them useful project management experience. So how did we go about designing such a challenging vehicle and what did we learn along the way?
The concept
The first milestone in the project was the Preliminary Design Review (PDR), which we submitted on New Year’s Eve. In this, we outlined our concept and made estimations of management elements such as budget and schedule. We came up with our concept design by supplementing the standard practices taught by the Department of Mechanical Engineering with our own knowledge of the peculiarities of the lunar environment. I produced an initial CAD model in Autodesk Fusion 360 and it was this that we used as visual inspiration going forward.
Detailed design
After the PDR came the Critical Design Review (CDR), for which the team did a great deal of analysis of each of the rover subsystems (propulsion, control and sampling). They described what had changed with their design since the PDR and outlined how the rover would be assembled and tested. My work on the CAD also meant we had a clear picture going forward of what the finished rover would look like and how the different parts would fit together. Once we submitted the CDR at the end of March, we received some feedback from an industry expert, which we then used to clarify our intentions during a Skype presentation to him.
Build phase
Once our industry expert had cleared us past the presentation, we could start work on assembling the rover. This progressed slowly at first because of exam season, but after that the team dived into cutting holes in our chassis, mounting motors and printing the wheels and sampler components.
Two of our electrical engineers, Laurabelle and Izzy, also very quickly put our video transmission system together, which will feed live video from a camera on the front of the rover back to the control point so we can see where we’re going.
Jacob and I spent several days in the mechanical engineering workshop filing, drilling and printing to put together the rest of the mechanical components, after Declan and Peter had prepared the chassis and installed the motors and their controllers. Only the electrical system is left to sort out now before we’re ready for the big test day in July.
The final test
The actual competition will take place at RAL Space on the Harwell Science Campus near Didcot, with Aqua Lunae competing against five other teams from universities around the country. The rovers will have two attempts at travelling to the centre of a crater in RAL Space’s moon yard, picking up a 500g sample of dry ice, then returning to the start point. Between the two runs they’ll also be subjected to a vibration test that will accurately simulate the shaking of a launch on a Falcon 9 rocket, so the rovers will have to be rigorously built to withstand this.
Overall, I’ve really enjoyed working with my team over the past few months on what has been a very rewarding but also challenging project. We’re looking forward to running our rover at RAL Space to really put Bath on the UK student space map and can’t wait to compete again next year.
Really interesting. Wondering - how do you pick up the dry ice? A claw-like arm, a suction or vacuum apparatus or some sort of scooping method - or is that a 'trade' secret? Good luck. Only 4 days to go. Janet. Canada
Hi Janet,
The dry ice is picked up by the red arm on top of the rover. The arm swings down in front, driven by a servo, then as the rover drives forward the dry ice is collected in the scoop of the arm. As the servo rotates the arm back over the top, the dry ice pours down the groove in the arm and into the hopper on the top of the rover, where it is held for the trip back to the lander. We didn’t use suction or vacuum because of the extra complexity and because they wouldn’t work in the airless environment on the actual Moon.
William