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Slides and presentation by: David Bjanes Rajesh Atluri SHOT II Post-Launch Presentation

Violet : A High-Agility Nanosatellite for Demonstrating Small Control-Moment Gyroscope Prototypes and Steering Laws. Slides and presentation by: David Bjanes Rajesh Atluri SHOT II Post-Launch Presentation June 10-13th, 2010 Boulder, Colorado. Expected Results.

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Slides and presentation by: David Bjanes Rajesh Atluri SHOT II Post-Launch Presentation

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  1. Violet: A High-Agility Nanosatellite for Demonstrating Small Control-Moment Gyroscope Prototypes and Steering Laws • Slides and presentation by: • David Bjanes • Rajesh Atluri • SHOT II Post-Launch Presentation • June 10-13th, 2010 • Boulder, Colorado

  2. Expected Results • We expect to store the following data on to the flash memory on the MCU board: • Telemetry from sensors • GPS data signal by the GPS Receiver (RXer) Board • We expect to read flight data using a data parser application. • Expected Conclusions: • Telemetry from sensors showed reasonable flight parameters. • GPS data was logged accurately on to flash memory. • GPS receiver picked up satellites.

  3. Actual Results • Telemetry: • Low g Acc.: -0.5 to -1.5 g when within range of measure • High g Acc.: -10 to -30 g varying greatly • X & Y coupled compared to Z in both accelerometer sets • Temp.: varied too much and recorded extreme values; periods of “stable,” realistic T ~ 25°C (+/- 5°) for ~10 seconds • GPS: • Recorded packets of raw data from receiver board • Post-flight algorithm that searches for key header did not return meaningful data  algorithm was operating with corrupt data • Clue: even if antenna does not Rx, the YEAR field should say “1980”

  4. Difference between Actual & Expected Results • Telemetry: • Temp. sensor could be inherently damaged, become nonlinear at extremes, or interacted with other system in an unexpected way in flight • Test data was mostly collected at room temp. ~ 20 °C • GPS: • The packet structure was not as clear reading post-flight memory than during test  corrupt bytes / interrupt timing • MCU may not be fast enough to store raw GPS data, even with selective filtering of the RXer output

  5. Conclusions • (Telemetry) How we interface sensors with CDH MCUs ought to work • GPS test did not meet our intended goals: • Did store the transmitted signal from RXer board • RXer did not operate reliably with Mega32 MCU • Impact on UN-6 Mission: • Importance of the Interface Board to the GPS System • IB’s program and serial interface takes some of the speed “pressure” off of CDH (MCUs) since RXer outputs at the fastest rate • IB is the reason GPS data can be stored at a rate that minimizes the FC resources used for GPS (GPS IB speaks CUCP protocol) • Lessons Learned • Leave more time for debugging, integration of modules, and thorough testing • The Right Hardware: getting the IB working properly OR having more memory on SHOT II would have made the MCU programming easier

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