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From a phone call to a satellite orbiting Earth
Xavier WernerSpace Structures and Systems Lab. Aerospace & Mechanical Engineering Dept. University of Liège
My background
2011: HELMo Gramme, Industrial engineer (electronics)
2011-2014: ULg, OUFTI-1 team member (COMM and payload)
2014-2016: ULg, Project Manager for OUFTI-1
2016-…: ULg S3L, Research Engineer: nanosatellite design
207/12/2016 Satellite Engineering - Nanosatellites
Outline
1. Objectives
2. Space Segment
1. Payloads
2. Orbit and mission analysis
3. Platform
4. Protoflight model
3. Ground segment
4. What’s next?
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Decrease size,Increase interactions!
1. Objectives
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→ Hands-on satellite experience for students
Primary Goal
1. Objectives
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→ Hands-on satellite experience for students
Primary Goal
Long-term Goal
→ Series of CubeSats for scientific experiments
Granular materialsFormation flying
1. Objectives
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Long-term Goal
→ Series of CubeSats for scientific experiments
→ Hands-on satellite experience for students
Primary Goal
Short-term Goal
→ Orbital Utility For Telecommunication Innovation
1. Objectives
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Outline
1. Objectives
2. Space Segment
1. Payloads
2. Orbit and mission analysis
3. Platform
4. Protoflight model
3. Ground segment
4. Unique experience for students
5. What’s next?
807/12/2016 Satellite Engineering - Nanosatellites
• Digital-Smart Technology for Amateur Radio
• Simultaneous data and voice digital transmission
• Complete routing capacity, including roaming
• 3 frequencies and 2 data rates
- VHF: 144 MHz (2m) 4.8 kbit/sec
- UHF: 435 MHz (70cm) 4.8 kbit/sec
- SHF: 1.2 GHz (23cm) 4.8 kbit/sec or 128kbit/sec
• Data : 1200 bps - Voice : 3600 bps
• Open protocol (! AMBE)
• GMSK modulation
2.1 Payloads – D-STAR
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2.1 Payloads – D-STAR
• 3 types of communications:
• Direct visibility
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11
2.1 Payloads – D-STAR
• 3 types of communications:
• Repeater zone
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12
• 3 types of communications:
• Internet roaming
2.1 Payloads – D-STAR
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13
2.1 Payloads – D-STAR
• Directly through OUFTI-1
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ARelais
D-STARRelais
D-STAR
Internet
BExtension
SAT
14
2.1 Payloads – D-STAR
• Through OUFTI-1 and internet
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• High-performance solar cells (30% GaAs triple junction)
2.1 Payloads – solar cells
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• Technology demonstration (…)
• Imaging
• Communications
• Earth remote sensing
• Biology
• Re-entry
• Debris removal
• Security (AIS, ADS-B…)
• …
Payloads – More and more applications!
1607/12/2016 Satellite Engineering - Nanosatellites
Outline
1. Objectives
2. Space Segment
1. Payloads
2. Orbit and mission analysis
3. Platform
4. Protoflight model
3. Ground segment
4. Unique experience for students
5. What’s next?
1707/12/2016 Satellite Engineering - Nanosatellites
CubeSats = secondary payloads
Orbit imposed by primary payload
Mission analysis
=
Analyze impact of this imposed orbit
designed for Vega maiden flight
1447 x 354 km, i = 71°
Very demanding!
But finally:
Soyuz VS14
437 x 683 km, i = 98°
More comfortable!
2.2 Orbit and mission analysis
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Outline
1. Objectives
2. Space Segment
1. Payloads
2. Orbit and mission analysis
3. Platform
4. Protoflight model
3. Ground segment
4. What’s next?
2207/12/2016 Satellite Engineering - Nanosatellites
• Payloads: no specific pointing requirement
• COMM: max 10°/s (avoid signal modulation)
• Mass, volume, and power constraints
Passive control is sufficient!
2.3 Platform – ADCS: requirements
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2.3 Platform – ADCS: passive magnetic
A permanent magnet interacts with the geomagnetic field, producing a restoring torque, which align satellite axis with Earth’s magnetic field.
The spacecraft will oscillate around energy minima
The oscillation are damped out by hysteretic rods.
2507/12/2016 Satellite Engineering - Nanosatellites
© B
lue
Can
yon
Tec
hn
olo
gy
© S
urr
ey S
pac
eC
ente
r +
Stel
len
bo
sch
Un
iver
sity
ADCS – State of the Art
Actuators:
- Magnetorquers- Reaction wheels
Sensors:- Magnetometers
- Star trackers
- Sun/Earth sensors- Gyroscopes
Pointing accuracy < 1°
+ propulsion (cold gas thrusters, pulsed plasma thrusters)
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2.3 Platform – COMM: IARU
• All links must be located within the agreed ham band specific space allocations
• Coordination process
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2.3 Platform – COMM: frequency bands
Uplink: 70-cm band (435 MHz, UHF)
Downlink: 2-m band (145 MHz, VHF)
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2.3 Platform – COMM: 3 channels
• Payload:D-STAR (GMSK, 4800 bauds)
• TC/TM: AX.25 telecommunication protocol:
• simple and standard within the ham community
• 2FSK, 9600 bauds.
• Beacon: extreme reliability (Morse code).
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• 01111110
• Start and end of frame
2.3 Platform – COMM: AX.25 frame
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• Source and destination
2.3 Platform – COMM: AX.25 frame
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• Type of frame (unnumbered)
• Link integrity
2.3 Platform – COMM: AX.25 frame
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• Protocol Identification (network)
• OUFTI-1 : 11110000
2.3 Platform – COMM: AX.25 frame
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• Useful information
2.3 Platform – COMM: AX.25 frame
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• Checksum
• Error detection
2.3 Platform – COMM: AX.25 frame
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General Model OUFTI-1
Application
Application PUSPresentation
Session
TransportTransport CCSDS
Network
Data link Data link AX.25
Physical Physical RF & Modulation
2.3 Platform – COMM: TC/TM
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ADF 7021Demod D-STARZone 1 et 2
ADF 7021Demod AX.25
BEACON
MSP430CodecD-STAR
MSP430 OBCTC/TMProcessing
ADF 7021ModulationAX.25 / D-STARRF
RF
RX:
435 MHz
TX:
145 MHz
Data
D-STA
RA
X.2
5
2.3 Platform – COMM: block diagram
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2.3 Platform – COMM: low-gain antennas
Two monopole (quarter-wave) antennas : 17 and 50 cm
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Too short !(non-radiating parts)
Re-dimensionningImpact on MECH
2.3 Platform – COMM: low-gain antennas
Two monopole (quarter-wave) antennas : 17 and 50 cm
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© ISIS
COMM: State of the art
• Mainly VHF & UHF
• S-band more and more used
• X-band (COTS available)
• Limitations: licensing, power,
ground segment
• Inter-satellites link
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2.3 Platform – EPS: requirements
• Defined by other subsystems
• Power needed by client
• Voltage required by hardware
• Influenced by orbit
• Eclipse duration
• Influenced by the mission
• Payload operation
Power budget
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Power Source
Power Storage Unit
Power Conditioning Unit
Users
2.3 Platform – EPS: block diagram
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2.3 Platform – EPS: solar cells
GaInP/GaAs/Ge on Ge substrate
Triple junction solar cells
At 28ºC 5207/12/2016 Satellite Engineering - Nanosatellites
Kokam SLB 603870H
54
2.3 Platform – EPS: 2 Kokam batteries
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2.3 Platform – EPS: conditioning
• Direct energy transfer
• Choice of unregulated bus with three DC/DC converters:
• 5 V
• redundant 3,3 V
Design validated by Thales Alenia Space ETCA
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Solar cellsprotection
Dissipation system
MECH circuit
Battery-charger module
MHP ( T, V, I )
Battery protection module
5V 3,3 V (A)3,3 V (B)
MHP protection
58
2.3 Platform – EPS: engineering model
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EPS: State of the art
• Triple junction solar cells (28-30 % efficiency)
• Li-Ion batteries (200 Wh/kg)
• MPPT: Maximum Power Point Tracking
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2.3 Platform – MECH: requirements
CubeSat Design Specification:“ 2.4.2. All deployables such as booms, antennas, and solar panels shall wait to deploy a minimum of 30 minutes after the CubeSat’s deployment switch(es) are activated from P-POD ejection.”
• Antennas are wound around a guide before deployement
• Dyneema retention wire is used
• Retention wire is melted by a thermal knife
6107/12/2016 Satellite Engineering - Nanosatellites
© ULg – JL Wertz
2.3 Platform – MECH: flight model
6207/12/2016 Satellite Engineering - Nanosatellites
Cre
dit
: A
less
and
ra B
abu
scia
Antenna – State of the art
• Mostly burned wire and spring material
• Patch antennas for higher frequencies (S, X)
• Inflatable devices under development
6307/12/2016 Satellite Engineering - Nanosatellites
I/Os
Texas
Instruments
MSP430
Periodic « heartbeat » signal
2.3 Platform – OBC: hardware
Reliability and simplicity
• One central processor, handles all tasks
• Doubled for redundancy: only one active at a time
6407/12/2016 Satellite Engineering - Nanosatellites
accelerations, low frequencies
2.3 Platform – STRU: requirements
6707/12/2016 Satellite Engineering - Nanosatellites
Engines, wind ; high frequencies
2.3 Platform – STRU: requirements
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Fairing jettison, stages separation
Engines, turbulences
2.3 Platform – STRU: requirements
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Modes 1 & 2
2.3 Platform – STRU: models vs reality
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STRU – State of the art
• Aluminum
• COTS or homemade structures, very similar
• Coming: composites, 3D printed
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Determination of the frame contact resistance: face 6 is heated up
Face 1 Face 3
2.3 Platform – THER: measurements
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Battery is too cold !
2.3 Platform – THER: analysis (cold)
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Hot spot due to dissipation transistor !
2.3 Platform – THER: analysis (hot)
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The available surface on the satellite panels is very limited.
Difficult to control the overall energy balance between the spacecraft and its environment.
2.3 Platform – THER: thermal control
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Copper angle bracket
Thermal control can be achieved by an appropriate study and design of the conductive links within the satellite.
2.3 Platform – THER: conductive links
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• Mechanical thermostats
• 2 thermostats per battery, in series
• 7.2°C 23.9°C
• 1 heater per battery
• 2 x 250mW patch heaters
• 26.3
• 59.4 x 35.6 mm
Heaters + Thermostats
2.3 Platform – THER: active control
8507/12/2016 Satellite Engineering - Nanosatellites
THER – State of the art
• Passive means (MLI, coating)
• Heaters for sensitive equipment
8707/12/2016 Satellite Engineering - Nanosatellites
2.3 Platform – Configuration
UHF antenna
Thermal knives
VHF antenna
Pumpkin structure
Solar cells
COMMBeaconBatteriesEPSMAIN OBCBACKUP OBC (FM430)
8807/12/2016 Satellite Engineering - Nanosatellites
Outline
1. Objectives
2. Space Segment
1. Payloads
2. Orbit and mission analysis
3. Platform
4. Protoflight model
3. Ground segment
4. What’s next?
8907/12/2016 Satellite Engineering - Nanosatellites
Engineering model qualification tests+ Flight model acceptance tests + Space
Protoflight model protoflight tests + Space(= qualification levels with acceptance duration)
2.4 Protoflight model: philosophy
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• Write, test, and correct integration procedures
• Perform integration at
Centre Spatial de Liège (CSL) of ULg
2.4 Protoflight model
© ESA
Tests at ESA/ESTEC thanks to ESA Fly Your Satellite! program
2.4 Protoflight model: TVC
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Tests at ESA/ESTEC thanks to ESA Fly Your Satellite! program
2.4 Protoflight model: vibration tests
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X-rays at ESA/ESTEC thanks to ESA Fly Your Satellite! program
2.4 Protoflight model: X-rays
EM FM
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102
Soyuz Flight VS14Centre Spatial Guyanais, Kourou25 April 2016
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2.4 Protoflight model: Launched!
103
> 500 Beacon messages received from HAM operators
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2.4 Protoflight model: signal received
Outline
1. Objectives
2. Space Segment
1. Payloads
2. Orbit and mission analysis
3. Platform
4. Protoflight model
3. Ground segment
4. What’s next?
10407/12/2016 Satellite Engineering - Nanosatellites
3. Ground segment
105
TCP / IP
D-Star
Repeater
Satellite
Extension
Ground Station
Control segment D-STAR segment
Mission
Control Center
12:05:49
TC / TM
channel
(AX.25)
User
channel
(D-STAR)
07/12/2016 Satellite Engineering - Nanosatellites
12:05:49
Mission Control Center Ground Station
GS computer
TCP / IP
Tracking card
Rotatorscontroller
CI-V
TNC
UHF/VHFTransceiver
Phasing line
Phasing line
azel H V H V
AX.25
FM UHF FM VHF
ControlPointing data
UHF Antenna
VHF Antenna
Serial Data
3. Ground segment
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Gateway
Controller
Duplexer
UHF module
Duplexer
VHF module
Internet
Tx Rx Tx Rx
D-Star Repeater Satellite extension
UHF/VHF Transceiver
TrackingSystem
D-STAR mod/demod
OUFTI-1OUFTI-1
3. Ground segment
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Outline
1. Objectives
2. Space Segment
1. Payloads
2. Orbit and mission analysis
3. Platform
4. Protoflight model
3. Ground segment
4. What’s next?
10807/12/2016 Satellite Engineering - Nanosatellites
• 1U CubeSat
• Design improvements based on experience
• 3 payloads:• D-STAR (OUFTI-1 mission)
• RAD
• IMU (Sint Pieterscollege – Jette, Belgium)
109
4. What’s next? OUFTI-2
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Main payload: D-STAR
• Digital Smart Technologies for Amateur Radio
• Digital radio protocol
• 2 modes :
• DV (Digital Voice) : Voice + data (145MHz, 435MHz et 1.2GHz)
• DD (Digital Data) : Data only (1.2GHz)
110
ARelais
D-STARRelais
D-STAR
Internet
BExtension
SAT
2
4. What’s next? OUFTI-2
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111
Secondary payload: RADDegradation of electronical components by radiations
• Same experience
• 3 different shieldings
Dose measured by a RADFET
4. What’s next? OUFTI-2
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Secondary payload: IMUDeveloped by secondary school students
Free access to space thanks to OUFTI-2
112
4. What’s next? OUFTI-2
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Platform improvements• On-Board Computer
• COMM
• Beacon
• Structure
• EPS
113
4. What’s next? OUFTI-2
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4. What’s next? Earth observation
• Innovation in space with ULg
• Scientific and technological demonstrations in an
educational frame
• Currently designing a new Earth observation mission
• Define potential applications
• Define satellite (payload and platform)
• Build first model
11407/12/2016 Satellite Engineering - Nanosatellites
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