COMP4970 Embedded Systems for Space and Satellite Applications

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COMP4970Embedded Systems for Space and Satellite
Applications

• Richard Chapman
• 115-230 MWF,
• Shelby 1124
• Summer 2008

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AubieSat Program

• Website
• http//space.auburn.edu/aubiesat-1/
• Auburn Student Space Program (AUSSP), Dr. J-M
  Wersinger
• AHAB high-altitude balloon program

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Aubiesat 1 Prototype
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What is a cubesat?

• 10cm x 10cm x 10cm
• 1 kg mass
• ejected from a P-pod that holds 3 cubes
• launched by a variety of rockets

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Cubesats

• Polar orbit
• 500-600km in height
• Orbit takes approx 100 minutes
• about 10 minutes above the horizon on a given
  pass
• 3-4 pass/day in Auburn

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Launch sources

• ITC Kosmotras Dnepr, brokered by CalPoly for
  U.S.A. schools
• Space-X or other startup
• ESA
• NASA

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Launch is expensive

• Minimum 50K to launch
• Est. 50K to develop a cubesat
• NASA is much more expensive, but less risky
• Startups are the most risky

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But it is very cool.
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Space is harsh

• Temperature extremes/cycling
• Vibration and acceleration while in launch
  vehicle
• Ionizing radiation
• No chance to repair
• Lossy radio link (-60dB)

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University satellite launches

• A small and exclusive club many have tried, but
  few have succeeded
• The successful are not always the famous, well
  funded schools

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Sometimes youre the windshield

• Cal Poly, San Luis Obispo
• University of Tokyo
• University of Louisiana, Lafayette
• University of Bogota, Colombia
• U.S. Naval Academy

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And sometimes youre the bug June 6, 2006

• A much-heralded attempt to launch 15 CubeSats
  built by 11 universities and one private company
  failed this week All of the satellites appear to
  have been lost.

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Contd

• The Dnepr-1LV rocket lifted off from Russia's
  Baikonur Cosmodrome in Kazakhstan at 1943 UTC on
  July 26. Various accounts indicate that the
  mission went awry less than two minutes after
  liftoff when the first stage failed to separate
  on time, causing an emergency shutdown of the
  rocket's main engine.

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Satellite Systems

• Systems Engineering (standards, interfaces)
• Structure (thermal and mech)
• Electric Power System (EPS)
• Command and Data Handling (CDH)
• Communication (COM)
• Payload (PLD)
• Attitude control and det. (ACD)
• Ground station (GND)

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Electrical Systems
t
COM
CDH
memory
yaesu vx-2r
tnc-x
sensors
mcu
switch
secondary rcvr
GND
radio
EPS
PLD
camera magnet- ometer
solar cells
tnc
user interface
regulators
charger
AX-25 sw
batteries
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Microcontroller

• Atmel Atmega AVR 8-bit cpu, 128L
• RISC architecture, 32 registers
• 128K flash, 4k EPROM, 4k SRAM
• 6 8-pin general purpose I/O ports
• JTAG ICE capable
• 1 to 16 Mhz clock, most instructions single cycle

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Interfaces

• 2 USART serial interfaces
• Serial Peripheral Interface (SPI)
• Inter-Integrated Circuit (I2C) bus
• general purpose I/O (pin configurable for one of
  the above interfaces or for gpio)

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Software Toolchain

• Atmel AVR tools C compiler and loader
• MicroC/OS-II real-time kernel and command line
  loader/tools, have a port to the AVR chips
• Download via serial port
• STK500/501 development board

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CDH Tasks

• Monitor and control EPS function, manage power
  consumption
• Decode and respond to commands from ground
  station
• Send audio beacons to COM

• Gather and store sensor data
• Control payload operation
• Mitigate errors due to radiation
• Recover from errors/power loss
• Control COM system

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Organization of the class

• Each teams solution must be integrated with the
  other solutions at each stage of the process
  (e.g. simulate the interface if it isnt working
  yet)

• A team will work on each of the tasks, to produce
  requirements, test procedures, a working
  prototype and most importantly, documentation

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Milestones

• MILESTONE ZERO hello world
• MILESTONE ONE minimal function
• MILESTONE TWO integrate, add functionality
• MILESTONE THREE complete functionality, working
  interfaces to all other systems

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Assigning people to tasks

• Name
• Grad or undergrad
• Experience with C/C (class, research,
  industrial)
• Experience with hardware interfacing (be
  specific)
• Experience with real time OS
• Anything else relevant