High Altitude Payload Design – A Mechanical Aspect

1. High Altitude Payload Design – A Mechanical Aspect Kaysha Young and Emily Bishop – Montana State University - Bozeman Advisor: Dr. Brock J. LaMeres Mechanical System : Configuration and Testing Payload Design Requirements Mechanical System : Performance BOREALIS Flight Final Enclosure Configuration Background: In this project, 6 female engineering students (Student Team) worked as part of an interdisciplinary team to design a high altitude balloon payload. The payload collected environmental information during a high altitude flight. This data was used by a Graduate Design Team (HASP Team), to ensure that their experiment could indeed be carried out safely. The Mechanical Design Team designed an enclosure that was thermally suitable and structurally stable enough to withstand the harsh conditions of the atmosphere and rough flight conditions. The team was required to design for both the Student and HASP Teams, creating one enclosure to accomplish both teams needs. The final configuration for this enclosure consisted of ½” expanded polystyrene insulation, wrapped with fiberglass cloth and resin, and coated with non –reflective Krylon Flat White Paint . Corner Brackets secured with screws were used as the attachment mechanism to the HASP Plate. Total External Dimensions: 5.875 x 5.875 x 6 in3 Total Interior Volume : 130.7 in3 System Requirements Above: The BOREALIS Balloon that the Student payload was launched on. Above and Left: Environmental data collected by the payload during the July 27, 2012 flight in Livingston Montana. The results from this flight proved that the enclosure is capable of keeping the interior temperature in the acceptable range of -40C to 60C, this enclosure was deemed safe to carry the HASP Team’s electronic system. Enclosure Assembly Below: Interior of the open enclosure - Stability corner brackets are in view Below: The enclosure with the electronics assembled and ready for flight Mechanical System Above: Exterior of the box before it was coated with the non-reflective paint Above: The final enclosure that the Graduate Design Team flew on the High Altitude Student Payload HASP Integration Structural System Thermal Considerations Cold Chamber Test Cold Chamber Test : Started the test at -60C. The temperature was slowly raised up to 20C. Data was collected during the duration of the test, proving that the electronics were kept within operating temperature. Temperature profiles collect during flight can be seen in the performance section. Structure Temperature Material Impact Enclosure Attachment • Structural System • Enclosure • The external volume may not exceed 5.875 in x 5.875 in x 11.8 • The internal volume must be at least 111.6 in3 • Attach Enclosure Structure • HASP • Enclosure must securely attach to HASP Plate and not be disconnected for the duration of the flight • Must be easily attached and unattached from the HASP plate for ease of assembly and disassembly • BOREALIS • Must attach to the BOREALIS rope connection system • Impact Forces • Must withstand a vertical impulse force of 10 G’s • Must withstand a horizontal impulse force of 5 G’s • Thermal Considerations • Materials: Similar to the MSU HASP Research Team structure materials • Polystyrene must be used for the insulation (approx. 1 cm thickness) • A non-reflective outer coating should be applied • Additional material or support structures will be needed to make the structure strong • Temperature 1. The internal temperature of the payload must be kept between -40 C and 60 C Impact Test A drop test was completed to test the ability of the enclosure to withstand an impact load. Below: Horizontal Test - Maximum Load : X - 8 G Y – 10 G Above: This figure displaces the results for the tests that the HASP Team had to pass before their payload was accepted to fly on the High Altitude Student Payload in September 2012. Interdisciplinary Design Team Members Conclusion The results show that the enclosure preformed it’s task completely. The electronics for both flights were indeed kept at an acceptable temperature and were safe from the elements of the atmosphere. The box showed little to no deformation after decent, proving that the enclosure was structurally adequate. Jennifer Hoff (EE) Kate Ferris (ME Alison Figueira (CS) MakenzieGuyer (CS) Emily Bishop (ME) Kaysha Young (ME) Above: Vertical Test : Max Force – 15 G Above: The over all acceleration : Max : 20 + G The vertical load reached 19 G. Acknowledgements: Thank you to the wonderful Student Design Team – This was one of the best learning experiences. Thanks to the Graduate HASP Team for trusting us to design the enclosure for your very important project. Thank You Brock for all of your patience and for making this project possible. Thank you Robb Larson for all of your Mechanical Advise when we needed it. Thank you BOREALIS Team for letting our payload ride up on your balloon. Thank you to Montana Space Grant Consortium for funding this project. **U.S. Department of Education TRIO Ronald E. McNair Post baccalaureate Program under Grant Award No. P217A090198 The enclosure showed no signs of wear or tear after these impact tests. The enclosure will withstand the G loads required by HASP