AUBURN UNIVERSITY STUDENT LAUNCH. Project Nova. 211 Davis Hall AUBURN, AL Post Launch Assessment Review

Transcription

1 AUBURN UNIVERSITY STUDENT LAUNCH Project Nova 211 Davis Hall AUBURN, AL Post Launch Assessment Review April 19, 2018

2 Table of Contents Table of Contents...2 List of Tables...3 Section 1: Launch Vehicle Summary...4 Section 2: Vehicle Summary...4 Section 2.1: Motor Specifications...5 Section 2.2: Flight...5 Section 3: Recovery...5 Section 3.1: Data Analysis and Results of Vehicle...6 Section 3.1.1: Altitude...6 Section 4: Rover...7 Section 4.1: Post Mission Report...7 Section 4.2: Mission Analysis...8 Section 5: Embedded Systems...8 Section 6: Education Engagement Summary...9 Section 7: Overall Experience Summary...11 Section 8: Budget Summary

3 List of Tables Table 1: Launch Vehicle Summary... 4 Table 2 : Summary of Educational Engagement Table 3 : Budget Allocation Table 4: Funding Sources

4 Section 1: Launch Vehicle Summary Table 1 gives the basic details of the launch vehicle. More information regarding the launch vehicle can be found in Section 2 of this report. Table 1: Launch Vehicle Summary Total Length Estimated Mass Motor Selection Recovery 113 inches 38.5lbs Aerotech L1520T Double Separation, Dual Deployment Section 2: Vehicle Summary The primary design philosophy of the team s vehicle body structure was to create a rocket that had the space necessary for all payloads and recovery systems while minimizing weight. The team found that an inner rocket diameter of 6 gave the necessary space for all of the team s payloads and a wall thickness of.125 yielded the required strength. The team reduced weight by utilizing woven carbon-fiber composite for the structures that were manufactured in-house. Four separate carbon fiber tubes were coupled together to manufacture a rocket that met both strength and safety requirements. The team has decided not to continue with braided carbon fiber as a body tube material for this year. The team successfully built and flew a braided carbon fiber rocket, but the weight reduction of the structure was minimal and the rugged shape of the skin overlaying the braid induced additional drag. With additional research, this construction style could improve rocket performance, but given time constraints the team constructed and flew a solid carbon fiber airframe rocket for competition purposes. 4

5 Upon completion of construction of an isogrid tube, the team realized that the design in the constructed configuration did not provide the performance improvements expected. For this reason, the team decided to default to standard, rolled carbon fiber tubes for the competition due to their lower coefficient of drag. Section 2.1: Motor Specifications The team was supposed to fly with the Aerotech L1420R. However, the team had to change the motor due to missing components. The team instead flew with an Aerotech L1520T engine which gave a smaller than desired specific impulse, 855 Ib s versus 1038 Ib s, and shorter burn times, 2.4 s versus 3.2 s necessary for the flight. Section 2.2: Flight The team successfully flew and recovered the rocket at the competition in Huntsville, Alabama. The rocket performed as expected; however, the desired altitude of 5280 ft. was not achieved due to the rocket using a weaker motor. Next year, packing checklists will be made and followed to ensure that all components of the rocket will be available at launch. The rocket reached an altitude of 4233 ft. before being successfully recovered. Section 3: Recovery The Auburn University recovery system design for this past season consisted of a dual deploy, triple parachute system. This design had two separation events during its descent. At apogee, a redundant set of black powder charges separated the nose cone from the rest of the rocket body and deployed the drogue parachute and the upper main parachute. At this event, the upper main parachute is held closed by a redundant set of Jolly Logic Chute releases. The rocket then fell under this configuration until the second event at 750ft. At this second event, the Jolly Logic System released and deployed the upper main parachute as well as a second set of redundant black powder charges in the middle of the rocket body. This second set of charges created a full 5

6 separation of the rocket and pushed the lower main parachute from its housing in the upper section of the rocket. The rocket then descended the rest of the way to the ground in two separate pieces under two separate main parachutes. Redundancy of both sets of charges was achieved through having two separate altimeters housed on the rocket, each with its own apogee and main charge. Section 3.1: Data Analysis and Results of Flight The recovery system did not perform exactly as designed. At an apogee of 4233ft. the drogue and rifled upper main parachute deployed according to plan. However, the main separation charges also deployed at apogee, causing the rocket to split into two separate pieces and deploy the lower main parachute prematurely. Upon descent of the upper section from apogee, the shock cord became entangled around the upper parachute and did not allow it to open even though the Jolly Logic Chute releases released. This caused the upper section to fall the entire way under drogue with a significantly higher velocity than intended of 57 ft./s. This final descent velocity combined with the weight of the upper section caused the rocket to land with a kinetic energy of 706 ft.-lbs. Albeit early, the lower section of the rocket did have full parachute deployment which allowed the lower section to descend with a more reasonable velocity of 19.7 ft./s and land with a kinetic energy of 144 ft.-lbs. Analysis of the launch vehicle after landing revealed that the mass of the rover was not taken into account for the lower section which caused the rocket to descend faster than it was designed. Both sections exceeded the limit on kinetic energy at landing, thereby invalidating the recovery. Section 3.1.1: Altitude The primary altimeter used was an Altus Metrum Telemega and it recorded a final altitude of 4233 ft. This altitude is lower than the projected final altitude due to the competition flight not being flown with the intended motor. 6

7 Section 4: Rover The deployable rover was the mission objective for the USLI competition. The rover consisted of a 3D printed onyx chassis with a set of 3D printed nylon treads. It utilized two 1000:1 12V Pololu Micro Metal Gearmotors for propulsion, with one motor attached to each side of the rover. These motors were controlled by an Arduino Uno and powered by a single 9V battery. In order to deploy the solar panels required for the mission, a third motor was affixed to the back of the rover. This motor unraveled an accordion folded stack of solar panels such that their solar cells were all face up. All of these functions were controlled by a command computer located with the team rover pilot, which transmitted instructions to the rover via an embedded antenna attached to an Xbee Pro 900 communication system. This system allowed for communication with the rover at an effective range of.5 miles upon vehicle body ground contact. In order to safely and effectively transport the rover, a rover bay was installed directly above the motor mount in the lower section of the rocket. This location was chosen such that when the rocket split at apogee to deploy its drogue parachute, the rover would have a clear exit upon landing. In order to ensure the rover did not prematurely exit the rover bay, a servo was installed on the back of the rover. This servo clamped onto a bolt at the base of the rover bay, held the rover in place, and released upon receiving a signal from the command computer. Section 4.1: Post Mission Report After flight completion of the rocket, it was discovered that communication between the command computer and the rover had been hampered. This was caused by damage to the rover s antenna system at an unknown point during rocket flight. However, communication with the rover was possible at close range, as the damaged antenna could still receive powerful signals. Unfortunately, the servo holding the rover inside the rover bay was also damaged at some point midflight, making automated extraction of the rover impossible. All other functions of the rover were tested and performed flawlessly after manual removal from the rocket body. Additionally, the lower section containing the rover landed approximately 2500 ft. from the launch site, and was in range of the command computer, had the antenna not been damaged. Upon inspecting the rover bay at the 7

8 landing position, the rover was oriented in an upright position and had an unobstructed path of exit from the rocket body to its solar cell deployment zone. Section 4.2: Mission Analysis This mission has provided valuable information on real world payload preparation and deployment requirements. It has highlighted the need for shock testing of all electronic equipment and the importance of backup systems. Additionally, it reinforced the benefits of durable construction in creating a payload for high powered rocketry. In analyzing the data obtained from this year s payload deployment, Auburn USLI is better prepared to produce a quality solution to any payload challenge presented. Section 5: Embedded Systems The IPDS (Internal Plate Drag System) was intended to control the final altitude of the rocket using flat plates that actuate out from the sides of the vehicle. The position of the fins was calculated using a PID controller using acceleration data from an accelerometer. The system consisted of: (1) NeveRest 40 Gear Motor with encoder. (2) 9V batteries. One battery for the motor shield and one for the Arduino Uno. (1) Arduino Uno controller. (1) Adafruit Motor Shield v.2.3. Interfaces the motor with the Arduino. (1) Adafruit Micro SD card breakout. Collects data printed from the Arduino. (1) Adafruit barometric pressure sensor. Used to calculate the current altitude. (1) Adafruit accelerometer. 8

9 Unfortunately, IPDS could not be flown at competition this year because it was not flight certified. The vehicle was unable to reach the target altitude during the system s qualifying flight and therefore the system did not activate. However, IPDS yielded good results in testing and will be used next year due to its modular design and simplicity. Section 6: Education Engagement Summary This year USLI was able to reach over two thousand individuals in our community during our outreach events. The team continued to maintain long term partnerships such as Drake Middle School Rocket Week, Auburn Junior High School E-Day, and local Boy Scout troops. By maintaining these partnerships over several years, the team can build a relationship with the community. Some of the students touring Auburn s College of Engineering this year remembered our team and team members from previous Rocket Weeks. By continuing to maintain consistent partnerships, the team can better prepare for events and have many team members knowledgeable and ready to help. Additionally, the team began to lay the groundwork for new events and had our first successful event with the Girl Scouts of America. The team s goal is to try to expand our outreach efforts every year to reach more of our community, and although planning for new events and making new partnerships cannot always be accomplished in one year s competition cycle, we do so anyways to build for the next year. ULSI has established a stockpile of Alpha rocket kits, tools, launchers and motors to allow us to flexibly respond to any opportunities for new outreach events without waiting on supplies. Next year the team plans to have more events and reach more participants. A breakdown of the team s completed events and participants is in Table 2: Summary of Educational Engagement on the next page. 9

10 Table 2 : Summary of Educational Engagement

11 Section 7: Overall Experience Summary This year experienced some setbacks, but the team has continued to improve and innovate and is proud of this year s performance. Addressing the negatives first, main issues encountered at Huntsville this year were non-deployment of the rover and the main parachute deployment at apogee. The rover issue was due to damage to the antenna that may be due to the last minute nature of the antenna attachment in the future the antenna will be better protected. The separation of the vehicle body into two sections and deployment of the main chute at apogee is also an issue that the team is confident that it will be able to fix in next year s design. After this year s launch, the team came up with the following new policies that we hope will improve our performance moving forward. The testing team will be restructured to serve more as quality control, and ensure that the other teams systems are fully functional prior to launch. On a related note, the rocket will be completely assembled (minus energetics, of course) a day or two prior to launch to identify any fitting issues and ensure integration. The number of positives from this year far outweigh the negatives. The vehicle team s ability to design and manufacture a reliable rocket design has been proven and a great foundation for future competitions. Testing and prototyping with isogrid airframes will continue and hopefully provide the expected weight savings. The recovery team has shown an ability to support a wide variety of sizes of rocket and custom made chutes to fit safely recover any size of rocket. The rover payload demonstrated the usefulness and the versatility of rapid design iteration through 3D printing and extensive testing. Although the altitude control system could not be flight certified, it is completely modular and ready to be integrated into next year s rocket with little modification. The team plans to continue to fabricate a backup rocket to provide an opportunity for freshmen to gain valuable experience. With no incidents to report, the safety officer can be considered to have performed his job well. Finally, our educational engagement continues to foster lasting community partnerships that will sustain our team s outreach efforts for years to come. In all, the Auburn Student Launch Team is satisfied with this year s performance, and the team looks forward to next year s challenge.

12 Section 8: Budget Summary The budgets displayed in Table 3: Budget AllocationSection 8: are the final costs allocated to the full-scale vehicle, research and development, the subscale (rounded up for a factor of safety), travel, and test flight fees. With the competition cycle over, this costs are not going to change, and any costs associated with educational engagement activities that occur over the summer will contribute to next year. The total expenses for this year therefore were $13,111, and based on the $16,500 amount for total funding presented in Table 4: Funding Sources, this leaves $3,389 left over. A major contributing factor to the team s surplus of funds this year was the success of the launches conserving materials and parts, as rebuilding was not necessary. Overall, the team is quite happy with how the finances were managed this year. Thanks to the extra money left over from this year, funds will be spent on accruing materials for level 2 certification flights, additional research for future endeavors, and updated facilities for next year.. Table 3 : Budget Allocation Item Cost Full-Scale $3, Sub-Scale $2,000 Travel $2,200 Educational Outreach $ Test flights (3) $600 Research and Development $1,794 Promotional Items $1,000 12

13 Total $13,111 Table 4: Funding Sources Source Amount Alabama Space Consortium $12,000 Dynetics $2,500 Lockheed Martin $2,000 Total Funding $16,500 13