Command & Data Handling October 31 st, 2008 Tyler Tracey Tommy Yuen Karim Barakat
October, 31 st 2008 Presentation Outline Subsystem Overview Top Level Requirements LP-1 C&DH Operational Phases Descent Phase Science Phase Data Budget Derived Requirements Future Work 1
October, 31 st 2008 Subsystem Overview The Lunar Penetrator Command and Data Handling Subsystem Shall: – gather, process, and format spacecraft housekeeping and payload data for downlink or onboard use – determine and distribute commands to other spacecraft subsystems 2
October, 31 st 2008 Top Level Requirements The C&DH subsystem shall: – Be capable of acquiring and processing all “required” data generated by spacecraft sensors at a given time. – Be capable of commanding all subsystems “necessary” at a given time. – Store “important” data generated by spacecraft sensors until it can be reported to the orbiting spacecraft. – Use COTS components wherever feasible 3
October, 31 st 2008 LP-1 C&DH Operational Phases 4 Descent Phase [40 minutes] Penetration Phase [1 sec] Science Phase [120 hours] Attitude determination and control will dominate Processing Power [Instructions per Seconds] Payload’s accelerometer feeds data to DSU at high frequency [1 KHz] -Provide control functions for onboard drill -Provide processing power for thermal & power control - Store science & engineering data - Telemetry formatting Report Phase [TBD] -Receive & Store image data from camera [dominate Data Budget] -Receive & store engineering data [health of all components] -Store science data with regards to the penetration phase -Telemetry formatting - Wait for downlink order from relay satellite
October, 31 st 2008 Descent Phase Processor EPROM Data Storage Unit Data Bus e.g. -CAN bus -RS 422 Accelerometers RAM Gyroscopes Digital to Analog Converters Multiplexers Main Booster Feedback Engine/Booster ON/OFF Control [0 V – 5 V] 5 Analog to Digital Converters Multiplexers
October, 31 st 2008 Digital to Analog Converters Multiplexers Science Phase Feed to Analog components for control functions ON/OFF Control (0 V, +5 V) [Multiplexers required] Processor RAM Data Storage Unit Data Bus e.g. -CAN bus -RS 422 Subsystem health sensors and payload analog components (Analog Outputs) Digital Sensors and components Camera Analog to Digital Converters Multiplexers EPROM 6
October, 31 st 2008 Science Data [Payload] Raw Data [bits]Sampling Rate (Hz)Word Size [bits]QuantitySampling Time Camera 640*480 resolution (8 bit depth) N/A 1 Camera 1024*1024 resolution (8 bit depth) N/A 1 Mass Spectrometer Thermocouple Accelerometer Gas analyzers / sensors Drill Engineering Data [Thermal] Thermocouple Engineering Data [Propulsions & ADCS] Accelerometers Gyroscopes Main Booster Feedback Engineering Data [Power] Battery Discharge Sensor Bus Voltage Bus Current Engineering Data [Communications] Subsystem Health Data Total with 640*480 resolution In Kbits: In Mbits: Total with 1024*1024 resolution In Kbits: In Mbits:
October, 31 st 2008 Derived Requirements The C&DH system shall – Survive impact and the effects of the environment thereafter for at least 5 days – Store Mbits for at least 5 days – Provide [TBA] MIPS processing power for ADCS control algorithm – Fit into a compartment of [TBD] size – Consume less than [TBD] watts 8
October, 31 st 2008 Future Work Command budget ADCS processing algorithm (Kalman Filter) Continue to refine our Data Budget (Space Packets) Study and compare existing technologies 9
Thank you Questions?