AMSAT Fox Satellite Program

Transcription

1 AMSAT Space Symposium 2012 AMSAT Fox Satellite Program Tony Monteiro, AA2TX

2 Topics Background Fox Launch Strategy Overview of Fox-1 Satellite 2

3 Background AO-51 was the most popular ham satellite Could be worked with simple equipment - HT and arrow antenna Widely used in scouting, educational and demonstration events Failed in November 2011 Need replacement ASAP! 3

4 Fox Launch Strategy Take advantage of large and growing interest in CubeSats Develop family of CubeSats with ham radio transponders that are attractive for hosting science experiments Partner with universities to develop science and education missions Get free launch from primary mission via grants or NASA ELaNa program After science mission completed, satellite becomes amateur radio transponder 4

5 CubeSat Technical Challenges Very small size (1U = 4" x 4" x 4") Very low mass limit - less than 3 lbs Limited surface area for solar cells - limited power Limited area for antennas 5

6 Fox Program Phases Phase 1 satellites (Fox-1) 1U structure FM repeater mode with sub-audible low speed data Digital data mode up to 9600 bps Phase 2 satellites (Fox-2) Probably 3U structure Software defined radio transponder Linear, FM and high-performance digital modes 6

7 Fox-1 ELaNa Proposal Proposal submitted to NASA for launch as an education mission - Nov 2011 Penn State student experiment (MEMS Gyro) Requested orbit km Requested launch - 2nd Half 2013 Accepted at priority 14 of 33 No launch date yet 7

8 Fox-based University Projects AubieSat-2 & 3 RadFxSat NASA InVEST grant 8

9 AubieSat-2 & 3 Proposal submitted for National Science Foundation grant Auburn, University of Alabama & AMSAT 1-year science mission - atmospheric physics Ham transponder after science mission is complete Response from NSF expected in November Grants are highly competitive! 9

10 RadFxSat NASA ELaNa proposal Vanderbilt University and AMSAT Fox-1 flight spare Primary focus - Space Radiation effects test bed Secondary focus - STEM education 10

11 RadFxSat - Mission Profile Experiment payload runs simultaneously with amateur radio transponder Experiment data transmitted via low-speed downlink Requested launch 2H 2014 Requested orbit - 650km (same as Fox-1) NASA ELaNa proposal due Nov 12 Response expected Feb

12 NASA InVEST Grant In-Space Validation of Earth Science Technologies Team of 2 universities and AMSAT Validate weather observation instrument Proposal due Nov 27 Launch 2H 2015 Selection expected by May

13 Fox-1 Overview 6 Solar Panels Power Card Battery Card 70 cm Antenna Science Payload IHU Card Power bus Magnetic Attitude Control 2 m Antenna Telemetry RF Rx Card RF Tx Card 13

14 Avionics PCB Stack Science Payload Battery Power IHU RF Rx RF Tx 14

15 Solar Panels 6 solar panels 2 cells per panel Spectrolab Ultra Triple Junction cells Space-rated 28% conversion efficiency 15

16 Solar Cell Characteristics 3 Spectrolab UTJ, 27cm 2, Full Sun, 28C 2.5 volts / watts volts watts milliamps 16

17 Generated Solar Power 5 4 Power (watts) 3 2 X,Y +Z -Z Total Degrees 17

18 Power Card Solar Panel MPPT Power Bus X 6 Solar Panel MPPT Telemetry Processor Telemetry To IHU 18

19 MPPT Operation Solar Panel DC/DC Converter Power Bus Feedback Control Max-voltage Sense Tracking Circuit 19

20 MPPT Test Circuit 20

21 Battery Card 6 Cadnica (NiCad) A cells 3.6 V nominal 12 watt-hours capacity Battery protection circuitry Active thermal control Telemetry processor 21

22 Battery Heater Test Prototype 22

23 IHU Card Collects telemetry information Operates science experiment Sends telemetry as sub-audible low speed FSK in transponder mode High speed FSK in data mode Executes commands from ground control 23

24 IHU Card (cont) ST Microelectronics STM32L Ultra low power CPU 32-bit processor 33 MIPS 128K FLASH program memory 16K RAM 128K non-volatile Magnetorestrictive RAM Micro-SD card MEMs gyros for student experiment 24

25 IHU Software Open source SW tools (GNU C compiler) LINUX or Windows development environment FreeRTOS operating system STM32 "Discovery" card for SW development FreeRTOS running on Discovery card Drivers for I 2 C, SPI, serial ports running Modems for high and low speed data done in software 25

26 RF Rx Card Operates on 70cm FM receiver LNA with SAW filter for high sensitivity Automatic frequency control Provides audio to IHU and RF Tx 26

27 Low Noise Amplifier 27

28 Rx and Tx Power Conditioning 28

29 RF Tx Card Operates on 2 meters Inputs from IHU and RF Rx True FM exciter Power amp produces > 400 mw 29

30 Tx Local Oscillator & Modulator 30

31 RF Power Amp 31

32 Attitude Control Passive magnetic system Aligns satellite z-axis with earth's magnetic field Bar magnet on structure Hysteresis rods on battery card for motion damping 32

33 Antennas 2 meter whip 70 cm whip 33

34 VHF Antenna Pattern 34

35 UHF Antenna Pattern 35

36 CubeSat Structure and PCB Stack 36

37 Assembled Fox-1 Satellite 37

38 AMSAT Classifieds *** HELP WANTED *** AMSAT is always hiring! Design engineering: mechanical, electrical, PCB design systems, software, project management, thermal design Satellite construction: PCB construction, parts procurement, component fabrication, assembly Satellite testing: environmental testing, functional testing, requirements and regulatory compliance testing Contact Tony Monteiro 38

39 Any Questions?