1. Team MADD Michael Davies Andrew Mountain Dan Hoang Daniel Brink Team MADD Michael Davies Andrew Mountain Dan Hoang Daniel Brink Power Distribution Control Unit

2. History/Background Citizen Explorer

4. Citizen Explorer-I (CX-I) Designed and built by students at Colorado Space Grant Consortium in Boulder. The mission design allows K-12 schools around the world to be involved as ground stations available to receive science data and telemetry from CX-I. Two instruments, an aerosol meter and UV detector, will be used by the K-12 students to take measurements on the surface of the Earth. A low level of artificial intelligence will be supplied to the spacecraft through the use of the Automated Scheduling and Planning Environment (ASPEN). ASPEN is used to maintain a spacecraft schedule in order to achieve the objectives a mission operator would normally have to complete.

5. MADD Project Purpose Design a new Power Distribution Control Unit (PDCU) for the Colorado Space Grant Consortium’s Citizen Explorer spacecraft. The new PDCU must meet CSGC’s reliability requirements and integrate as a functional subsystem the satellite.

6. Control the power distribution to seventeen component systems of the spacecraft Receive desired state commands from the flight controller and ensure that the component system is in the desired state – otherwise send flight computer an error message Store the state of each relay into memory every 5 seconds, in case of a power failure Check for proper functionality of flight computer Authorize digital signature from flight controller, otherwise provide a power pulse to restart flight controller Relay the status of the PDCU through voltage, current and temperature readings MADD Objectives Software Functionality

7. Using a 12V source, provide four alternate voltage power buses Secondary Objective is to design the 24V boost converter Using relays that receive a signal from the micro controller, control the power distribution to seventeen component parts of the system Fit the dimensions – 7.15" X 7.65" X 2.7" Build wire wrapped prototype Transfer to PCB MADD Objectives Hardware Functionality

8. Nature of project reliability is a critical concern Included in design should be ability to check proper function of system Devise a system for testing to prove reliability Expand the test to use LED or other display devices Emphasis on very tight, consistent and reliable code MADD Objectives Reliability

9. Flight Computer PDCU Micro Controller Relays Critical Decoder ADCSScienceCOMM Power Converters Battery Thermistors PCB

10. LED Power Converters 17 Relays Micro Controller Flash Memory Therm RS485 CPU PCB

11. Micro Controller Manufacturer: Microchip Technology Part number: PIC16C877 Micro controller specified by CSGC Choose the 877 over 77 because of the flash memory incorporated into the chip RS-422/485 chip Manufacturer: Maxim Integrated Products Part number: Max3082E Provides communication between micro controller and flight computer Hardware

12. RS-232 chip Manufacturer: Maxim Integrated Products Part number: Max208 Provides mechanism for interface with PC serial port, can be converted to RS-422/485 Relays Manufacturer: Crydom Part number: DM063 Part specification from CSGC Hardware

13. Thermistors Manufacturer: Yellow Springs Instrument Part number: YSI44901 Memory Flash or FRAM –Looking into the necessity of memory in addition to the memory on the micro controller, depends on program storage requirements –FRAM more stable for space conditions –Decision to be made within a week Hardware

14. Power 24V boost converter –CSGC design Power Buses all capable of 5 watts –15V converter –-15V converter –5V converter –12V converter Hardware

15. Risks Unfamiliar technology Part availability Time constraints Funding Risks/Contingency Contingency Help from Space Grant Order parts early Drop PCB UROP/Space Grant

16. Project Schedule

17. Divisions of Labor Mountain: PCB Design Brink: Hardware Layout Davies: RS422/485 Protocol, PIC Programming Hoang: RS422/485 Protocol, PIC Programming