Student Rocketry: Out-of-Class Learning Experiences from a Year-Long Capstone Project at University

Abstract Work in Progress, Student Paper: Student Rocketry – Out of Class Learning Experiences from a Year-Long Capstone Project at University Abstract Every year, teams nationwide participate in rocket competitions such as the Spaceport America Cup 1 or NASA Student Launch Challenge 2. These competitions have various altitude requirements that student-designed and built rockets must reach to qualify. Although most rockets meet the altitude requirement to qualify, they typically overachieve and fly beyond the threshold. In this paper, we describe the process of a senior design project to design, build, and test a Rocket Altitude Determination and Response System (RADARS) to reach within ± 50 ft of a given target altitude. To achieve this, our team will integrate an airbrake control system on our rocket, designed to decelerate the rocket during ascent using real-time data. Testing how rockets behave in flight can be challenging; however, it can be done using wind tunnel tests, Computational Fluid Dynamics (CFD) simulations, and physics-based dynamics simulations. Extensive topical knowledge is required to perform each of the tasks successfully. Moreover, rocket launches and flight tests bring their own requirements of operations and safety. This knowledge is readily available at many academic institutions with established experimental rocketry programs through coursework and institutional knowledge. Our University does not have any courses focused on rocket design, fabrication or operations; consequently, to complete this project, our team has to seek this information and learn outside the classroom. This paper will describe the steps we have taken to accomplish this (including where to seek the information, struggles, and successes) and document the process to serve as a roadmap for other student teams in similar situations at their universities. Our first step towards this goal was to explore the use of an open-source software program, OpenRocket 3, designed to simulate the flight and dynamics of a custom-designed rocket. Among other results, OpenRocket can estimate the stability margin of a rocket and how that affects its flight; this information will be used to evaluate the placement of the airbrakes in the rocket as it changes the stability margin. The open-source software, mainly developed for a niche segment, has advantages and shortcomings. The significant advantage is that it is open source – meaning it is free and provides access to its source code. Resource-strapped student teams, like ours, can leverage this to analyze preliminary designs. It also has a vibrant community of users and developers and can be a knowledge resource. On the other hand, a potential downside is that a community develops this, and updates to the software and documentation happen on their schedule. For instance, as of this writing, the user manual was last updated in February 2022. We have not yet encountered issues with this, but we anticipate doing so. Another aspect of our effort is the simulation of our custom airbrake designs – in the form of actuated fins. OpenRocket allows a limited creation of such structures as thick fins, which is inadequate for our purposes; our team is exploring the use of CFD simulations and wind tunnel tests to determine the position of the airbrakes. With the help of OpenRocket software, we chose to explore using another opensource software for CFD simulations, namely OpenFOAM 4. Simulations using the OpenFOAM CFD are computationally intensive to be executed on standard desktop/laptop computers. To address this issue, we have put together a custom computing cluster using available hardware at our university. The cluster hardware consists of 20 desktops, each with an Intel i7-4790 quad-core 3.60 GHz processor and 16Gb of RAM, running Ubuntu 22.04.3 LTS connected to a 24-port gigabit switch. One of the computers on the cluster is designated as the main computer, which communicates with each node using Open MPI 5 and shares directories using Network File System (NFS). The user can also use each node from the main computer using the Secure Shell Protocol (SSH). The cluster will run CFD simulations using OpenFOAM. While we were able to leverage the free and open-source software packages, it did involve a significant investment of time in self-directed learning to assemble the cluster hardware, ensure its functionality, and the installation and testing of OpenFOAM. While our University offers classes on high-performance computing (HPC), there are no corresponding classes on building a computing cluster. For this task, our team explored using ChatGPT 6 as a resource to help translate and debug code, complementing online guides for building the cluster. While the wide use of ChatGPT among students has only generated negative responses, we intend to explore and document its use as a resource to learn skills outside the classroom, particularly as it pertains to our project, hoping to serve as a framework for other student teams. Other aspects of this project involve the hands-on portion, including the fabrication process, integration of the avionics, and testing and validation; as with the other aspects, these are not taught in formal classes at our university. We intend to seek input and guidance from the model rocketry community in our area and our peers at other academic institutions. While this has been a great learning opportunity so far, much work is left to do. In the final version of the paper, we will describe and document our efforts in acquiring the knowledge and hands-on skills needed to meet the goals of our capstone project.