• 2-Unit (2) CubeSat Bus:

  • 1U of internal payload volume

  • Nanoracks NRCSD compatible

  • 1.5 W average bus consumption

• Payload average power: 240 mW

  • Up to 5 W peak power

• Solar array: Body-mounted panels

  • Solar panels on ±X, ±Y, and -Z faces.

  • 7 W peak power.

• Battery: 12 Whr LTO battery

• Pointing accuracy:

  • Nadir pointing nominal

  • 3-axis stabilization

  • 1-axis (pitch) control

  • Roll and Yaw angles: < 5° error

  • Pitch angle control: < 1° error

• On board GNSS receiver:

  • Time synchronization to UTC

  • Positioning, altitude, velocity data

  • Patch antenna on Zenith face

• Data Rate: 10 kB/s down/uplink

• Antenna: 437 MHz UHF dipole antenna

• On Board Computer:

  • Safety-critical Arm Cortex-R5F

  • Dual-Core Lockstep CPU

  • Dual-redundant Real Time Clocks

  • Data storage: 128 Mb NOR Flash

  • Firmware storage: 128 Mb ECC NOR Flash

  • 256 Kb MRAM

• Over-the-air Firmware Updates

• Housekeeping Telemetry Collection:

  • Temperature

  • Voltage, current, and power consumption

  • Logs and flags

• Payload Data Bus: SPI

• Propulsion: None

• Expected mission life: 1.5 years in LEO

• PC104 cards:

  • Accommodates off-the-shelf subsystems

• 6061-T6 aluminum

• Hard anodized rails

• 316 stainless steel fasteners

• Loctite Blue 242 on all fasteners

• Internal fasteners epoxied with 3M Scotch-Weld 2216 B/A Grey

• Manufactured in Victoria BC

• Accommodates PC104 cards

• 8x deployment levers

• Omron D2F

• Each pair wired in parallel for redundancy

Overview

• Inspired by and based on OpenLST by Planet

• PC104 compliant form factor

• Single 5V DC input with application specific low noise 3.3V and 4.2V rails

• Input reverse polarity protection

• Transmit power consumption of 5.12 W and receive power consumption 0.24 W

• ESD protected digital & RF I/O

• External watchdog for SoC and manual reset functionality

• UART interfaces for C&DH & debug @ 9600bps

• Bootloader programming via CC-DEBUGGER

Communication Parameters

• ITU emission designator 25K0F1DBN

• 25 kHz necessary bandwidth

• Uncoded 2-FSK modulation

• Data whitening with the PN9 sequence

• Custom packet radio format with variable packet length

• Data rate of 10.17 kbit/s and deviation of 6.18 kHz

• AES-128 uplink encryption (permitted by ITU RR. Vol. 1 ART. 25 Sect. I 25.1 § 1), and unencrypted downlink

• Over the air firmware update capability

RF Parameters

• Texas Instrucments CC1110 SoC

• Qorvo RFFM6406 front end (PA & LNA)

• SMA-F type RF output matched to 50 Ohm

• Nominal TX power of 32 dBm at antenna port

• Sensitivity of -112 dBm at 10.17 kbit/s data rate & 6.18 kHz deviation, using 2-FSK

• On chip frequency offset (Doppler) compensation

• TCXO frequency reference, 1.85 ppm accuracy

• Receive SAW-type bandpass filter

• DC blocked RF output

Regulatory & Testing Considerations

• Hardware timer to comply with ITU RR. Vol. I ART. 22 Section I 22.1 (positive space station transmitter control, ISED approved method)

• Experimentally verified compliance with out of band emission limits set out in ITU-R SM.1541-6

• Experimentally verified compliance with spurious emission limits outlined in ITU-R SM.329-12 and Appendix 3 of the ITU Radio Regulations

• Experimentally verified receiver sensitivity performance

• Experimentally verified thermal performance in vacuum

Overview

• Half wavelength deployable tape dipole

• Burn wire antenna deployment mechanism with GPIO interface to C&DH

• Manual arming mechanism for deployment system for safe handling

• PC104 compliant form factor with reduced header size to simplify assembly

• Delrin antenna deployer, held shut but braided Dyneema fishing line

Construction

• RG-178B/U coaxial feed with direct connection from the coaxial conductors to the dipole arms (no impedance matching network)

• Lossy choke balun comprised of a single coax turn on a Fair-Rite Mix 61 round core (Fair-Rite P/N 2661480002)

• Series bleed resistors (2x 10k 0603) on antenna arm connected to coax center conductor

RF Characteristics

• Tuned by length trimming after installation in spacecraft bus, measured input VSWR 1.02:1 at 437 MHz

• Roughly 95% antenna efficiency, computer from anechoic chamber measurements

• Peak gain of 3.89 dBi

• Deployment from port-starboard sides of spacecraft, dipole pattern largely preserved

Testing

• Initial in-house verification at University of Victoria anechoic chamber (directivity pattern, estimated max. gain, input characteristics) with tin spacecraft mock-up

• In-depth characterization by Antenna Test Lab in their professional chamber with incomplete but realistic spacecraft model (ideal length estimate by manual tuning, input characteristics, gain pattern, efficiency at ideal length)

• Final verification in flight-like spacecraft model at CSA David Florida Laboratory ATF2 facility

Off-the-Shelf CubeSpace Y-Momentum ADCS

Sensors:

• Deployable magnetometer

• Fine sun sensor

Actuators:

• 2x Rod magnetorquers (±0.24 Am²)

• 1x Air core magnetorquer (±0.13 Am²)

• Momentum wheel for momentum bias and pitch control

  • Speed range: ±8000 RPM

  • Max momentum: 1.77 mNms

  • Max torque: 0.23 mNm

Estimation Modes:

• MEMS Rate Filter

• Magnetic Rate Filter

• TRIAD

• Full-state EKF

• MEMS Gyro EKF

Control Modes:

• Detumbling

• Y-Thomson

• Nadir Pointing

Pointing Accuracy (Nadir Pointing Mode):

• <10° in eclipse

• <5° in sunlight

Processor:

• Automotive-grade Texas Instruments TMS570 microcontroller

  • TMS570LS0714PGE

• Dual ARM Cortex-R4F cores, operating in lock-step

• ECC integrated flash and RAM banks

• Radiation-tested up to 6 krad

• Core clock: 80 MHz

External Memory:

• Telemetry and Log File Storage: 128 Mb NOR flash

• Firmware Storage: 128 Mb ECC NOR flash

• Non-volatile Configuration Storage: 256 Kb MRAM

Auxiliary Components:

• Dual-redundant real-time clocks

• Hardware window watchdog

• Temperature sensor

Integrated GNSS Receiver:

• NovAtel OEM719

Operating System: FreeRTOS v9

Filesystem: ARM Mbed LittleFS

• Files are organized in daily directories

• One telemetry file exists per subsystem per day

File Uplink and Downlink Protocol:

• CCSDS File Delivery Protocol

• Operated in deferred NAK mode

Command System:

• Both immediate and scheduled commands are supported

• One command is sent at a time; a single response is then awaited. A retry protocol is enacted if the response is not received within a certain timeout.

Non-volatile configuration table:

• Table of non-volatile settings that allows tweaking of various configuration settings (eg. timeouts, counters) without requiring a new firmware upload

• Each table is associated with a firmware version

• Up to 3 tables are stored in MRAM

Bootloader:

• Enables over-the-air firmware updates via CFDP protocol

• One un-upgradeable image lives on-board at all times

• Up to three slots available for uploading a new firmware image

Mission Control:

• Custom Python GUI application

• Built using Kivy 1.11

• Automated ground pass set-up and execution

• Manual command control and response display

• File uplink and downlink interface

• Log and data file viewing

• Developed in parallel with OBC

  • Main tool for testing during development

  • Now doubles as ground control software for flight

Regression Testing:

• Automated test sequencing and execution

• PyTest framework

• Command and response checking

• Tests for bootloader and firmware uploads

• Tests targeted at specific OBC firmware features and corner cases

• Tests for integration of several subsystems

• Tests for execution of the satellite concept of operations

  • Increment time on OBC

  • Check scheduled commands execute in correct order at correct time.

Firmware Unit Testing:

• Ceedling

Telemetry Database

• Database: MongoDB

• Cloud Provider: fly.io

• Frontend: NASA OpenMCT

Interfaces:

• Control/testing over EGSE UART link

• Control/testing over RF link with radio in-the-loop

  • Both wired and wireless links

Fun Statistics

• Over the course of 4+ years, the on-board computer firmware repository has accumulated:

• 2546 commits

• >32000 lines of code developed in-house

• 329 merge requests

Maximum Power Point Tracking System:

• All solar arrays connecting in parallel through blocking diodes

• Tracks entire array

• Defaults to fixed voltage tracking

• Voltage sweep tracking on command

Efficiency:

• High end-to-end efficiency

• Day Time Efficiency: 83% average

• Night Time Efficiency: 73% average

Multi-channel output:

• Centralized converters

• 4x 3.3 V channels

• 2x 5 V channels

• 2x 12 V channels

• 1x unregulated channel

Output Power: 20 W across all channels

Power Conditioning and Distribution:

• Voltage Accuracy: ±3%

• Line Regulation: ±0.5%

• Load Regulation: ±3.5%

• Transient Recovery Time: 150 us

• Transient Response: < 10% output voltage change, 0% to 100% load

• Rise Time: < 10 ms

• Ripple and Noise: < 2% Vp-p max, < 0.5% Vp-p average

Output Channel Protection:

• Short Circuit Protection: Latch Off, < 5 us

• Over Current Protection: Current limit, < 5 us response

• Over Voltage Protection: Clamp at < 120% typical output voltage, < 10 us response

• Fault flags to indicated if a channel has been shut down

Telemetry collection:

• Current, charge (mA), and energy (mW) consumed per output channel

• Battery SoC, Time at Full Charge, charge/discharge current, voltage, temperature

• Solar array output voltage, current, and temperature

Power Management Interface: SPI

Debug Interface: USB

Turn On Condition:

• In sunlight

• Deployment switches released

• Does not require charged battery to turn on

Launch Provider Compatibility:

• Nanoracks NRCSD for space station deployment approved

Deployment Timer:

• 35 minute deployment timer

Heartbeat:

• Requires 1 pps heartbeat from On Board Computer to keep alive

• Resets all output channels for 11 seconds if heartbeat signal is interrupted.

Power Management Configurations:

• Disables:

  • Entire power system (OFF EPS)

  • Just output channels (OFF DIST)

• Enables:

  • Force on EPS (ON EPS)

  • Force on debug interface (ON TLM)

• Timers:

  • Disable deployment timer (FAST ON)

  • Disable reset timer (OFF HEART)

Total Energy:

• 12.2 Whr, 2.6 A @ 4.7 V average

Charge specifications:

• CC/CV charge: 2.6 A (1C), 4 A (1.5 C) max, 5.3 V cutoff.

Discharge specifications:

• 8 A (3C) max discharge current, 3.2 V cutoff

Self Discharge:

• < 1 % of capacity per week

Cell Type:

• Hard cylindrical 65.4 mm x 18.5 mm

• Lithium Titanate Oxide (LTO)

Operating Temperature:

• Charge: -20 °C to 50 °C

• Discharge: -35 °C to 75 °C

Thermal Control System:

• Passive thermal control

• Battery chemistry can safely charge/discharge at temperatures < -20 °C with no permanent capacity degradation

Configuration:

• 4 cells in 2S2P

• No active balancing

Battery Management System:

• Short Circuit Protection (21 A. 250 us response)

• Over/Under Voltage Protection (5.46 V / 3.14 V, 1.25 s / 144 ms response)

• Over Charge/Discharge Current Protection (9.1 A / 9.1 A, 8 ms response)

• Latch off fault response

• Voltage, current, and temperature monitoring

Nanoracks Compliant:

• Passes Nanoracks NR-SRD-139 “Nanoracks Test Requirements for Lithium-ion Batteries Applicable to CubeSats & Small Satellites on the ISS”:

• Cell and pack characterization/testing

• Vacuum tested

• Vibration tested (hybrid satellite/battery vibration test profile)

Power Generation:

• Large panels (starboard, port, and zenith) produce 4.8 W peak

• Small panels (ram and wake) produce 2.4 W peak

Solar Cell Type:

• Azurspace Triple Junction GaAs solar cell assemblies

Integrated Sensors:

• Course sun sensors for attitude estimation

• Temperature sensors for thermal model validation

Substrate:

• Ventec VT 447 b high absorptivity substrate

Connectors:

• Large panels connect to ram/wake panels via board-to-board connectors (Samtec SIR1)

• Small panels connect to EPS via cable harness (Molex Picolock)

• Separate harness for course sun sensors to all direction connection to ADCS

[1] Bus Module Bracket

[2] M2.5 Mounting Holes

[3] CubeSpace CubeComputer

[4] CubeSpace X-Axis Magnetic Torquer (air core)

[5] CubeSpace CubeControl

[6] CubeSpace Y-Axis Magnetic Torquer

[7] CubeSpace Z-Axis Magnetic Torquer

[8] CubeSpace CubeWheel Small (Y-Axis)

[9] Interface Board

[10] NovAtel OEM719 GNSS Receiver

[11] On Board Computer

[12] Power Management Module

[13] Power Conditioning and Distribution Module

[14] Battery Pack

[15] Radio

[16] Radio Heatsink/Shield

[17] Antenna PCBA

[18] Antenna Burn Wire Resistors

[19] Antenna Deployer

[20] Antenna Balun

(A) Fine Sun Sensor Connector

(B) Deployment Switch Connector (Starboard)

(C) Ram Solar Panel Connector

(D) Wake Solar Panel Connector

(E) Antenna Deployer Connector

(F) Magnetometer Connector

(G) OBC Debug Connector

(H) GNSS Antenna Connector

(I) EPS Ground Charge Connector (not shown)

(J) EPS Debug Connector (not shown)

(K) Battery Management System

(L) Battery Pack Connector

(M) Radio Antenna Connector

(N) Radio Configuration Access

(O) Radio Debug Connector

(P) Course Sun Sensor Connector

(Q) Payload Module Connector

(R) Deployment Switch Connector (Port)