Lituanica SAT-1. AMSAT-UK Colloquium July, Gintautas Sulskus AMSAT-UK International Space Colloquium July, 2014

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1 Lituanica SAT-1 Gintautas Sulskus AMSAT-UK International Space Colloquium July, 2014

2 Lituanica SAT-1 team is very grateful to radio amateur community for all support and enthusiasm! Thank You!

3 Driven by the Idea Launch the first Lithuanian satellite Take the first photo from space Stimulate collaboration between universities Raise the interest of general public Create a platform for future projects Create new opportunities for business and education

4 The Mission Article about the first Lithuanian satellite Core team HW Dev New competitor SW Dev Testing Sent-off to NASA Launched by Antares, aboard Cygnus Ejected from ISS First contact! Comm problems Brownouts Finally, got under control Re-entry Development Jul 2012 Oct 2013 The wait Impatience 9 Jan Feb 2014 Fun ~29 Jul 2014

5 Lituanica SAT-1 Architecture ARM module (OBC) Lituanica SAT-1 Comms with GS, SAT control Peripherals URAT - commands, data transfer I2C - EPS control, telemetry, WD Electrical Power System I2C multimaster Arduino module UART ARM module FM Repeater UART Transceiver Ground Station

6 ARM module Arm Cortex M4F 32 bit, 192kb Ram, 92 MHz, 3.3V Downclocked Sensors Gyro, accel and magnetometer SD Card Telemetry data storage Watchdogs the link with GS

7 Helium-100 FSK/GMSK transceiver Frequencies TX: MHz or MHz RX: MHz or MHz Sensitivity: BER 10-3 Max bandwidth: 38.4kbps, full duplex AX.25 protocol

8 Arduino Atmega 2560V-16AU 8bit, 8MHz, 8kb RAM, 3.3V Beacon Message updates, ON/OFF Camera SD Card Photo storage Watchdogs ARM

9 Arduino Module: BeeLine Radio Beacon FM or CW modulation Frequencies MHz Transmitter power -20 to +12 dbm Starts independently Guaranteed communication

10 Arduino Module: Camera VGA 640x480 JPG compression Automatic exposure Manual focus (infinity) Fisheye lens

11 Selfie

12 Electrical Power System GOMSpace - NanoPower 3.3V@3A and 5V@3A fully controllable channels Predefined power modes Blackout, Brownout, Safe, Nominal Watchdogs I2C bus

13 Electrical Power System: Solar Cells Silicon based Custom built Low cost Still in good condition

14 FM Repeater TX MHz RX , 67 Hz CTCSS Only 2 more in orbit Saudi SO50 - full time ISS - activated manually Feedback Good conn quality & pwr efficiency Simple equipment for comm

15 FM Repeater Prototype

16 Key System Requirements Fault tolerance Failures anytime, anywhere Redundant component control Via SW and HW power channels Watchdogging Power modes Safe, Nominal, Science Lightweight Network Protocol commands, packet data transfer

17 Experimental Requirements Specification An attempt to leverage formal methods Requirements specification in natural language Translation to mathematical model (Event-B formalism) Stepwise refinement of SAT states Correct requirements according the mathematical model Barely scratched the surface Still highlighted some inconsistencies in requirements Time consuming, slow

18 Abstract level: Physical On/Off

19 1st Refinement: Control Zones

20 2nd Refinement: Power Modes

21 3rd Refinement: Operational Modes

22 Implementation Decisions Good old C for SAT Keil RTX for ARM Arduino package for Atmel Ground Station Erlang Communication Lightweight UDP-like network protocol Developed in-house

23 ARM SW Architecture Background tasks always initiated No new tasks are ever created Schedule CMD [Received CMD] Scheduler [max 10 CMDs] All cmd s go into scheduler Create Runner task [Delay=0] Operations run as tasks Runner Lib Stack Background Operation Tasks (On/Off) Telemetry Housekeeping Power manager (Always ON) Scheduler Discard CMD [PowerMode=FAIL or OpMode=FAIL] Continue with CMD [PowerMode=OK and OpMode=OK] Remove from Scheduler stack

24 Success Criteria Minimal Get it launched Deploy antennae Possible problems in the first few weeks Receive radio beacon signal Nominal Establish SAT-GS communication Test FM repeater

25 Success Criteria Maximum Satellite stabilisation Receive telemetry data Take photo Misfortune Telemetry archiving to SD card does not work (ARM module) Pleasant surprise OSCAR-78, or LO-78 award!

26 The First Photo

27 Lessons Learned Operators struggled to use the satellite Confusing functionality: overlapping EPS and ARM power modes Poor\Lack of documentation or reluctance to read it :-) Do it quickly and make it right later does not work! Do not try! All timers must be configurable! Use homogeneous environments for reusability (e.g. only ARMs) Reflash option

28 Thank You!