Project Overview:

This is a Tether Based Capture System designed for a CubeSat class Project. This capture system works largely like a fishing net, which is cast out towards the target, captures the target, and then remains attached via a high strength line. Initially, we hoped to buy a prefabricated tether system but couldn’t find one that fit our requirements. As far a we could find, the only mission with a similar system was the removeDebris mission by ESA; but that system was made for much larger applications, weighing in at around 40 kg for the capture system alone. The next place we looked was within the drone capture market. More specifically we looked at devices that law enforcement uses to capture drones who have entered into unauthorized air space. These systems are handheld, but were unfortunately still too large. The only remaining option was to design a custom solution. Our solution consists of a spring loaded mechanism that would expel projectiles, attached to the net, towards the target. We believe that this solution successfully fits all of our requirements.

The images below show the first and second concept designs. The first concept utilized pressurized canisters that would accelerate projectiles when electronically actuated valves were released; I ran into major issues simulating this process. The simulation required transient CFD, which I have done for other projects, but couldn't get to work for this complex design. Because of this, the easily simulate-able spring loaded design was the final choice; this design uses a spring which is released via a servo motor to expel the projectile towards the target.

This system uses a stereoscopic camera system to calculate the distance towards the target. The feed from each camera runs through an algorithm which extracts features from the images using ORB (oriented fast, rotated brief) tracker, the position of the features is then used in conjunction with principles of stereoscopic images to calculate the distance to the target and relative velocities. Optimally, this data would be used with an autonomous control and navigation algorithm to achieve the correct position and orientation before capturing the target CubeSat.