TARGIT CubeSat Target Subsystem
Background
For a little background information, The Tethering and Ranging Mission of the Georgia Institute of Technology (TARGIT) is a CubeSat Mission with the primary objective of demonstrating a LiDAR imaging system on a CubeSat platform. In order to test this imaging system, the satellite will deploy a small target with its own power system, electronics, communications equipment, and sensors, that will inflate a mylar balloon. This mylar balloon will serve as the target for the satellite’s imaging operations.
System Overview
On another page, you can see my work on the electronics used inside the “target” subsystem. This page mostly contains my work on the target subsystem structure and its manufacture/assembly. I started working on the target subsystem during the summer of 2019 and continued working on it through the spring of 2020. The target structure houses all of the necessary systems to allow the mylar balloon I mentioned earlier to inflate so that the main satellite can image it. This includes solar panels, retroreflectors, batteries, a microcontroller, a pressurized gas reservoir, valves, a hard mounting point to tether the target to the main satellite, and a number of other systems. The poster below, which a friend and I presented at the 2019 Symposium on Space Innovations, gives a good overview of the system operations.
In order to inflate the balloon, pressurized gas must flow from a reservoir through air channels and valves and into the balloon. Due to the complexity of these reservoirs and channels, the target structure is almost entirely SLA 3D printed. The basic idea is that there is a centerbody composed of several 3D printed parts. These parts incorporate a number of features, including a gas reservoir, recesses for electronics and a battery, and a series of air channels. The centerbody structure is surrounded by spring-loaded hinged panels that fold out once the target is deployed from the main satellite. While the basic geometric constraints of these parts were established when I began working on the project, I ended up designing from the ground up much of the structure. The flight hardware was outsourced to a professional 3D printing company using SLA technology and a material with high stiffness and temperature resistance. We actually were able to get my designs manufactured before the end of the spring 2020 semester, which was super exciting. To prototype the structure, I used a Formlabs Form 2 SLA 3D printer with standard resin. Using the same printing technology as the professional manufacturers allowed me to see what sort of features were possible to print and which features would be problematic.
Future Work
The design phase for the target structure is largely complete. As mentioned earlier, we’ve ordered the professionally manufactured parts and are in the process of moving on to assembling flight hardware and testing.