Northern Arizona Space Aviation (NASA) 22'-23' Electrical Engineering Capstone Project NASA Rocket Competition NASA has a yearly competition for schools to compete in and the competition this year is a new one. This year’s competition is going to be including 69 university teams that will build a rocket that will be launched in Huntsville Alabama in April of 2023. The team from Northern Arizona is comprised of the NAU Rocket club, a mechanical engineering capstone team and an electrical engineering capstone team. Together we will build a complete rocket system that will be sent one mile into the air and safely come back down. Once the rocket has returned to the ground level, an on-board camera system will then proceed to complete several tasks that are going to be transmitted by the NASA management team through a 2 meter HAM radio. In each area of this project the NAU teams look to achieve a successful build. Electrical engineering capstone team in front of NAU Engineering Project Component Information NASA RAFCO System Power In order to power all of our electronics in the system, we are going to use three lithium ion batteries each rated at 3.7 votls and 2000 miliAmp-Hours. Two batteries will power our controller and the other will power a servo motor. Communication In order to communicate from the ground to the rocket, we are utilizing a software defined radio dongle which is going to receive between 144.9MHz and 145.1MHz. In that receiving system will also be an antenna. Microcontroller The microcontroller that will be used on the rocket will be a Raspberry Pi 4 model B. This will take the incoming radio call signals and convert those signals into executable movements for the on-board camera. Camera The on-board camera must have a FOV of at least 100 degrees and be able to take several pictures in color and monochrome. To meet these requirements we have gotten a SEE3CAM CU 81 camera which has 120 degrees for its field of view and can switch between color and monochrome. Electrical Research Antenna The antenna configuration wasn’t a priority initially. Once the team had gone through the Preliminary Design Report for NASA, that is when we realized how severe our size restrictions were. We had run the calculation for a monopole antenna and that showed us we needed a 19.2” to receive anything as low as 144MHz. After extensive research from the book “Antenna Engineering Handbook” by Richard Johnson and through meetings with professors Julie Heynssens and Paul Flikkema we realized we could use a helical antenna that is much shorter than a monopole and receives in an omnidirectional manner. That narrowed our search for an antenna and we were able to find a 6.63” helical antenna that allows us to be within our size constraints. Antenna equations for 2 Meter Radio Power diagram for the Pi Parallel battery system Power System Our power system is a critical one because the electrical system itself needs to be on for a minimum of 2 hours. While it might not seem like it that big of an issue on the surface, finding batteries small enough for the power bank that the mechanical engineering team has allotted for us it difficult. We ended up going with three 3.7-volt lithium-ion batteries. We figured that since the Raspberry Pi would also require a 5-volt input that we would also include a DC-DC boost converter in the power delivery. The schematic on the left shows a depiction of how the system would be wired, that being the battery terminals would feed into the boost converter stepping up our voltage from 3.7 to 5-volts. We need to do this or else once that battery hits a minimum voltage of 3.3-volts the Raspberry Pi will shut off even though the amp-hours still allow for more usage from that battery. The reason for having three lipo (lithium-ion) batteries is that two of them will be placed in a parallel configuration like the bottom image. Wiring thee batteries in this manner will double our amp-hour lifetime. Those two lipo batteries will be connected to the boost converter then into the Pi. The last lipo battery will be connected to our servo motor. However, we will still have the signal wire from the servo being fed back into the Pi, so that it can attain information coming from the Pi while not drawing any power from it. This setup will hopefully allow us to be function for 2.71 hours according to the numbers we’ve worked out. We have been notified by our capstone professor that there is some concern with the batteries having an difference in each of their potentials as well as some current runaway issues on the Pi, all of which we hope to have solved by the start of the next semester. Interdisciplinary Overview This project is again a combined effort between three teams. Us on the electrical capstone side are only concerned with developing the camera system that will be housed in the payload portion of the rocket. It is a new addition to this year’s competition, so we are doing an extensive amount of research about radio engineering. The mechanical engineering capstone team is focused on the deployment of the payload system and getting it free of any obstruction. We have been working together to bounce ideas of placement of parts in order to have the payload system itself work efficiently with no issues. The NAU Rock Club is in charge of building the entire rocket body along with its propulsion system and altitude sensors and parachute system. They are also running simulations that have mass budgets in the to see how the rocket will react during its flight. The small image on the right is an illustration of the various subcomponents that will be included in the rockets final build. Though the detachment points for the rocket are not shown, it will be jettisoned into two parts by the main shute and droge shute. Electrical Engineering 10% Mechanical Engineering 20% Rocket Club 70% ELECTRICAL ENGINEERING TEAM Jarrard Mountain Team Leader Greetings, my name is Jarrard Mountain and I am the team leader of the RAFCO portion for the NASA payload on the rocket. RAFCO is the radio frequency command that will control an onboard camera system. I am grateful for the opportunity to be working along side the Mechanical Engineers as well as the Rocket Club. Timothy Singleton Website Coordinator My name is Tim Singleton. I am 33 years old and a senior at Northern Arizona University. Born and raised in Maryland, I originally attended college for my paramedic’s degree. I changed professions at 26 and decided to study electrical engineering. Ever since I changed fields, I have thoroughly enjoyed learning as much as I can about designing circuits and how these circuits are implemented into a final product. I also enjoy hiking, snowboarding, fishing, riding my motorcycle, and spending time with my wife and our two dogs. I am incredibly excited to have been chosen for this project. Lane Dempsey Scheduling Manager Hello, my name is Lane Dempsey! For this 2022 NASA Student Launch competition I am part of the electronics system design and radio frequency engineering teams. What made me pursue this NASA project for my capstone project was the opportunities to learn new areas of electrical engineering and mechanical engineering, and obtaining multidisciplinary skills sets as a future engineer. CONTACT Send us a message: Flagstaff, AZ, 86001 Email: jdm678@nau.edu | tas626@nau.edu | lhd29@nau.edu Northern Arizona University Fall 2022