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AMSAT Fox-1 Overview . AMSAT Engineering Team 2011 Space Symposium. Fox-1 Introduction. AO-51 replacement 1-Unit CubeSat (4" x 4" x 4") Target orbit 650 km Magnetically stabilized FM transponder IHU for telemetry and command Science experiment. Fox-1 Operational Modes.
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AMSAT Fox-1 Overview AMSAT Engineering Team 2011 Space Symposium
Fox-1 Introduction • AO-51 replacement • 1-Unit CubeSat (4" x 4" x 4") • Target orbit 650 km • Magnetically stabilized • FM transponder • IHU for telemetry and command • Science experiment
Fox-1 Operational Modes • Transponder Mode • FM repeater • Telemetry data sent as low-speed FSK in sub-audible band • Command Mode • Transmitter dedicated for data downlink • High-speed FSK • More power available for running experiment
Special "ZombieSat" Features • Designed to extend usable life • FM Transponder will operate with dead cpu • FM Transponder will operate without ground station intervention • FM Transponder will operate while in sunlight even with dead (shorted) battery
Fox-1 Systems • Power System • Internal Housekeeping Unit (IHU) • RF System • Antennas • Science Experiment
RF System Fox-1 System Diagram Power System Solar Cells Battery Power bus 70 cm Antenna 2 m Antenna Science Experiment IHU Sensors
Power System - Solar Panels • 6 solar panels • 2 cells per panel • Spectrolab Ultra Triple Junction • Space-rated, high radiation tolerance • 28% conversion efficiency
Solar Cell Characteristics Spectrolab UTJ, 27cm2, Full Sun, 28C
MPPT Operation Switching Supply Solar Panel Power Bus Pulse Width Control Max-voltage Sense Tracking Algorithm
Power System - Block Diagram SPV1040 +Z Panel Power Bus MPPT Battery Protection SPV1040 X,Y Panels MPPT (x2) SPV1040 -Z Panel PIC I2C Interface Battery 3 x NiCd MPPT
Power System - Battery • 3 x NiCad cells • 3.6 V nominal • 10 watt-hours • 10% depth of discharge • Charge: 0 to +45 C • Discharge: -20 to +60 C
DC Power Available • 1.9 watts min in sunlight (no battery) • 2.2 watts average (max eclipse) • 2.8 watts average (no eclipse) • 10 watts peak power
Internal Housekeeping Unit • Collects telemetry information • Supports science experiment • Sends telemetry as low speed FSK w/FEC in transponder mode • High speed FSK w/FEC in command mode • Executes commands from ground control
IHU Microcontroller • STMicroelectronics STM32L151VBT6 • ARM3 Cortex CPU (32-bit) • Up to 33 MIPS @32 MHz • Designed for "ultra" low power consumption • 128K FLASH program memory • 16K RAM • On board RTC, D/A, A/D
RF System • 70 cm FM receiver (uplink) • 2 m FM Transmitter (downlink) • Transponder mode provides FM repeater • Command mode for running experiment
FM Transmitter Transponder Mode CTCSS Decoder 2-minute Timer PTT 70 cm Antenna 2 m Antenna FM Receiver Audio IHU Commands Low Speed FSK
FM Transmitter Command Mode 70 cm Antenna 2 m Antenna FM Receiver IHU Commands FSK Experiment
Antennas 2 meter whip 70 cm whip
2.0 1.5 SWR 1.1 1.0 VHF Antenna SWR
2.0 1.5 SWR 1.1 1.0 UHF Antenna SWR
Science Experiment • Penn State University - senior design project • 3-axis MEMs gyro sensor • Measures satellite spin rate, spin direction and wobble about the magnetic axis in orbit • May include GPS receiver
Fox-1 Team Developers Advisors Logo by Steve Kenwolf
Sound Like Fun? • AMSAT is always hiring! • Engineering: mechanical, electrical, systems, software, project management • Satellite construction: PCB layout, parts procurement, surface mount construction, parts machining, testing Contact Tony Monteiro, aa2tx@amsat.org
Any Questions? AMSAT Engineering Team 2011 Space Symposium