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While many others may be travelling to their favourite vacation spots around the world for the first weeks of the summer, our Deployment Demonstrator Mission (DDM) engineers were drawn to a place away from sunny beaches and poolside drinks: our Delft lab. Usually working together remotely from Austria and the Netherlands, several members got together for two weeks of intense prototyping and testing of our Tumbleweed rovers’ design.
Throughout the past year, the DDM engineers have been working hard to improve the structure of our rover. In July, some went the extra mile to accelerate progress on the prototyping: Ben Placke, Lead Mechanical Engineer for the DDM project, and Project Manager Nils Neumeister made the trip from Austria to join their colleagues in Delft. Especially for Nils, being back in the lab was a change of pace: “It’s been a while since I’ve been actively involved in the day-to-day engineering, so being able to actually get my hands on what we have been working on is really exciting. While being able to work remotely is in many ways a good thing, it’s very important for me to be able to see it in person as well.”
At first glance, the construction of a Tumbleweed rover may seem simple: A spherical structure of arcs, intertwined with sails to let the wind carry it across the Martian surface. In practice however, all of these components must come together to withstand the rough Martian terrain, and perfectly execute a crucial part of the mission: the unfolding sequence. However, mid-air deployment and unfolding is estimated to reduce the cost of the landing systems by a factor of 100. Moreover, the lighter systems increase the availability for payload, allowing the rovers to cost-efficiently deliver more data. This approach is entirely novel to Mars exploration, meaning our engineers must tackle a variety of complex tasks.
Until their deployment above the Martian pole, the Tumbleweeds are transported in a folded state. During their descent, the rovers unfold, their sails slowing them down. After landing softly on the surface of the Red Planet, the Tumbleweeds can begin their data collection. This unfolding sequence forms one of the central engineering challenges for the members of our DDM team. The nodes holding the arcs in place are essential to a functioning mechanism.
Sabin Ilegitim, one of our Delft-based Structural Engineers, is thrilled with the technical progress achieved this month: “With the 3D printers in our lab, we could do one iteration of the design of the nodes per day. Over these two weeks, we were about four times faster than usual! I really enjoyed getting so much done and working together with the people in the lab – it doesn’t even feel like you are doing work, more like we are just having fun together.”
As with any engineering project, a wide array of tests must be performed with the rover prototypes before they can leave our home planet. To simulate the Tumbleweeds’ descent onto Mars, our engineers performed several drop tests with the structure. This resulted in some marked successes for the team: “The rover did exactly what we wanted, we did not expect it to work as well as it did. After making some more changes, including the thickness of the arcs, we did another drop test that also worked out fine. Now we know what we need to work on for the next iterations”, Sabin summarizes.
Ben further explains what these steps include: “We want to further iterate the mechanism of the node to try and make it lighter and more compact in general to increase the rover’s rolling capability”. He adds that one of their biggest upcoming goals is to make the node mechanism open up using a wirelessly transmitted signal. Motivated by their progress, the engineers are already planning on doing another stint in late August, where they plan to take further strides toward these goals and perform the next drop tests.
Nils is proud of what the team has been able to achieve: “Now we’ve gotten to a stage where we’re having very successful tests, which truly showcases the hard work that the entire team has been putting into their work”. We look forward to seeing their next successes!
For further information, please contact office@teamtumbleweed.eu.