UKSEDS Satellite Design Competition: It’s now or never

Hello, I’m Iain and Co-team lead on Strath AIS’s entry to the UKSEDS Satellite Design Competition this year with the Astrathnomical team. This semester we have been working on the Critical Design Review (CDR) for the CubeSat developing the specifics of the design, the operations, the manufacture, and the test plan. This is a continuation of the work we did during the Preliminary Design Review (PDR) last semester so make sure you’ve read Emily’s blog explaining what we did for the PDR. 

We continued with our previous team of loyal members, managing to recruit 3 new members to join us whether they were interested or a captive audience for our sales pitch. Not only this, UKSEDS put us in contact with our tutor Mark Muktoyuk, an engineer at Astroscale: a company developing active methods of catching actual space debris. He has provided us extensive and useful advice on satellite design through regular meetings and encouraging the team to do their best, advising the use of caffeine to fuel innovation when necessary.  

New Design for the Robot Arm

Our mission continued from we left off, continue to develop our CubeSat to detect and capture a piece of space debris within UKSEDS’s mystery room.  We developed our ideas from being conceptual to fully thought-out system through the course of the Critical Design Review (CDR). We got started on this right away (a few weeks) after getting feedback that we’d actually done pretty well (surprised?).  

The sub-systems continued to develop their individual sections, Systems keeping everyone on budget while developing the Concept of Operations (CONOPS), budgeting being their most important work, as it turned out making everything as cheap as possible cost efficient while remaining functional would be a theme of the work on the CDR.  

Ben and Alistair continued their work on the robot arm, reducing the cost of the components, and streamlining the design so that it will fit in a smaller volume. A new streamlined version of the robot arm is shown below, still looking awesome if a little smaller. They also developed the control flow chart to carry out the capture process and started work on an inverse mathematical model to drive it to the correct position.   

New functionality to the detection payload has been added by Haroon, developing Computer Vision (CV) software. This was done with advice from Strathclyde Alumnus Noel Png, who is an Alba orbital engineer and has very kindly helped us understand computer vision algorithms. The CV software will allow the satellite to detect debris automatically, and provide us with details about it position, speed, and orientation. Below is an example of the software in action, detecting one of the most common pieces of space debris – an iPhone case. 

Test of the Computer Vision Algorithm 

The Attitude and Orbit Control System (AOCS) also worked on the theme of low cost, with Magdalena replacing some of the components with cheaper but just as functional alternatives as well as adding an Arduino nano to control it. The Arduino will evaluate the signals from the sensors and use this to find the position of the satellite and rotate the motor to reach the desired attitude for the satellite.  The motor will drive a fly wheel Zara designed which will when rotated will cause the satellite to rotate through conservation of angular momentum. Zara also made a Simulink model of the satellite was then designed which will allow the controller to be dialled in and has provided assurance that the AOCS will achieve its requirement and to tune the control loop used, the model is shown below.  

Simulink Model of the Satellite's Dynamics 

Preben has been working on communications, making sure that all the components will be able to connect to their raspberry pi (on board controller), and that they will have the necessary read/write rate for the data we need to transfer. This was also done for transferring data over Wi-Fi to the “ground station” analysing how the data can be compressed and packaged to minimise the bandwidth required. The relations between the different components can be seen in the System’s Architecture Preben made: 

Satellite System Architecture

Power has continued development under new team member Arman and competition veteran Nepheli, completely overhauling the subsystem. This included the replacement of the previously selected battery with two smaller batteries allowing them to fit into the structure. More importantly they designed protection circuitry to ensure that none of the components are accidently melted and that no one handling the satellite gets electrocuted. The overall circuit diagram of the satellite is shown in professional detail below.  

Circuit Diagram of the Satellite 

Finally, structures began development this semester under Joel, providing us with the long-anticipated CAD model of the satellite, and the chassis that will hold it together. The chassis has been developed from aluminium bar and plate that will provide plenty of space, structural rigidity, and will allow it to be easily recycled, improving the mission’s sustainability. He also analysed the satellite’s structure to assess whether it would be able to withstand the extreme conditions of launch and the somewhat less extreme conditions of the mystery room. 

CAD model of the satellite

If all this work isn’t enough to impress you, it certainly was enough to impress UKSEDS as we came first in this stage of the competition, doing excellently in our trade-offs and further development since the Preliminary Design Review. Beyond doing well the team had a great time developing the satellite to a state where it is ready to be built, and we can prove this as we submitted a document of the team’s comments on how they enjoyed their experience and learnt new skills, which were definitely not written under duress. 

With the CDR complete we will now be entering the final stage of the competition where we will build the CubeSat and it will then be tested within the mystery room, detecting and capturing a piece of debris. The team is looking forward to getting into labs to finally start building and testing our design. So stay tuned for the blog covering the final part of this journey and see how we do in the final part of the competition. 

If you have stuck around this long, congrats you’ve got a great attention span. If you have found the competition interesting there will be plenty of opportunity to get involved in Strathclyde’s next entry to the satellite design competition, as well as StrathAIS’s other teams.