#Created by Mikey Limotta and Lance Plater
Our drone consists of a simple design that adds onto the current sphere drones on the ISS. Since the weight and transportation to and from the ISS has a large price tag, our team wanted to design something that was as light as possible and utilizes realistic technology instead of theoretical technology. Such theoretical technology, such as a plasma generator, may pose an unknown threat to the astronauts once developed. Furthermore, the cost to produce and send a plasma generator to the ISS would only be a complex solution to a simple problem.
One disadvantage to the SPHERES drones is the lack of space inside the drone to allow for new sensors. Furthermore, since GPS serves no purpose once a space craft is in orbit, the SPHERES drones are only capable of recognizing each other without any awareness of where they are located in the ISS. Our drone attachment design solves this problem by utilizing QR codes on the walls of each space module. Once the drone scans the QR code, the drone will know which component of the space station that it is currently in. This will allow the drone to become aware of it’s current location (in front of the QR code) and the location of the package-for-transport inside said space station module. Additional QR codes on the packages would also allow the drone to confirm that it has located the correct package. As the drone returns with the package, each module's QR code would be scanned until the drone reaches the module where it left off. The camera also doubles as a depth sensor, measuring distances autonomously so it does not interfere with equipment or endanger the astronauts.
The SPHERE drone add-on will be a circular sub-assembly that mounts to the SPHERE. Because using the existing CO2 propellent is not enough for the 5lb payload, fans will be used in the add-on to counteract this. The subassembly itself would consist of two tubes to contain the necessary electronics and batteries for the subassembly. Additionally, the subassembly will contain eight fans for maximum manueverability and to compensate for the greater amount of inertia that will be needed to propel the drone. The bottom of the subassembly will contain two claws to grasp (autonomously) normal and abnormally sized items that are currently on the ISS. These claws can also pull a large tote bag that astronauts can place their items into.
In order to recharge, the drone will have a docking port with a autonomous capabilities, similar to the iRobot’s autonomous docking capabilities. The autonomous program would be similar to the iRobot’s program. However, the program will have to be modified to include a z axis variable for docking. The docking station itself will have a converter to convert 120 V DC (station power) to 12 V DC (the drones power). The drone will not be utilizing the 68 V or the 120V plugs in the other station modules where a large amount of clutter may exist. Rather, the charging station will be placed with the other experiments where charging plugs are readily available and accessible.
The drone will be utilizing standard computer fans as a method of propulsion. While such fans may have a weak pushing force, an astronaut on the Skylab Space Station had recalled that only a small breath would cause someone to propel forward. The fans will be located in tubes with perforated holes on the sides to allow for air flow. The perforated holes will prevent the drone from making a drastic course turn due to the suction the fans produce. Additionally, the drones will not need CO2 canisters, unlike the original SPHERE models. The CO2 canisters would need to be constantly replaced, thus adding more and more weight to the next payload delivery.