Overview

My Mechanical Engineering capstone project at Virginia Tech  was completed in a team of seven people and sponsored by The Aerospace Corporation. We were tasked with developing a system for deploying a 50cm x 50cm cross-dipole antenna from a small satellite of 10cm x 10cm x 30cm (a 3U CubeSat), while only taking half of the available volume and weight, leaving the rest for the theoretical scientific payload of the satellite.

We developed a deployment mechanism using a spring-loaded hinge and an electronically controlled burn-wire to time the release. The design had to meet NASA GEVS standards in order to be validated for launch from the International Space Station, a common method of deploying CubeSats. We conducted environmental testing to validate the design's thermal, vibration, and pressure performance using industry-grade testing machines at the Aerospace Corporation testing facility in northern Virginia.

To start the project, we established the customer needs with the primary stakeholders, our client and project sponsor The Aerospace Corporation. Ideal and marginal values were established for all criteria, as well as importance. Several designs were generated and evaluated against the design criteria using a decision matrix to choose a final best design. Then, we had to create CAD models of the design, run vibration simulations on the models to ensure natural resonances were outside the relevant range, construct prototypes, and build a complete functional model for testing. We also had to keep track of our project budget and timeline, keep a Bill of Materials, perform failure and mitigation analysis, and complete four major reports documenting the design and build progress, each accompanied by a presentation to a panel of professors, industry professionals, and our Aerospace Corporation sponsors.

My Main Contributions

In addition to assisting with the overall design, manufacturing, testing, and reporting like all team members did, the following are the specific aspects of the project that I was the team member primarily responsible for completing.

• I was the Electronics Lead on the team, and was responsible for designing and programming the electronics controlling the burn-wire.

  • Determined what microcontroller and accessories we needed.

  • Programmed the control code using Python and JavaScript.

  • Tested burn-wire failure points to determine correct burn-wire gauge and power requirements necessary for a successful deployment, without risking the heating element breaking before the release cable.

  • Implemented the electronic design into the mechanical design to ensure proper function.

• In charge of most test runs for the design, as the burn-wire mechanism is the primary aspect of conducting a test run and that is what I was in charge of, so operating it was mainly my responsibility.

• Used the team's CAD model of the design and Unreal Engine to create a photoreal animation of the design deploying in the target environment of low earth orbit. We used this in all of presentation materials throughout the project, and received very positive feedback from the audience that it helped them understand the design by being able to see it in action.

• During the idea generation phase, I created two unique antenna deployment designs, two unique designs for potentially mitigating vibration damage, and detailed diagrams of what would become our final design to refine the concepts and sync up the team vision.

• Created a simple prototype of one of our early tape-measure coil designs, similar to our final design, as a proof-of-concept. Also created a wooden prototype of the our final antenna design demonstrating the functionality of the coil mounted to the lid and successfully deploying.

• Created the team's final presentation poster design and was responsible for writing most of the content on it as well.

• Created the team's final presentation video, showcasing the design and manufacturing process.

• Cleared up early confusion regarding desired antenna dimensions with the project sponsor. Initially, we were unclear if the antenna was supposed to be 50cm across overall or have each arm of the cross-dipole be 50cm, and talking during meetings with no visual made this distinction hard to clear up. I created diagrams and emailed our project sponsor to clear up the confusion, which the team was highly appreciative of. We were then able to proceed knowing that the antenna was intended to be 50cm across overall, resulting in 25cm arms.