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Introducing a Low Cost and High Performing Interoperable Satellite Platform based on Plug-
and-Play Technology for Modular and Reconfigurable Civilian and Military
Nanosatellites
Fredrik Bruhn, Per Selin and Robert Lindegren (ÅAC Microtec )
Indulis Kalnins (University of Applied Sciences, Bremen)
James Lyke and Benjamin Hendersson (USAF/AFRL/Space Vehicles)
Josette Rosengren-Calixte and Rickard Nordenberg (FMV)
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Outline• Introduction – International agreement in plug-and-
play spacecraft• Space plug-and-play Avionics (SPA)• Improved miniature plug-and-play
–Protocol–Hardware
• New SPA avionics and power hardware• QuadSat-PnP spacecraft based on SPA
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Introduction – The ”NAPA” Agreement *• Project name: Nanosatellites Plug-and-Play Architectures
(NAPA)• This agreement (U.S./Sweden – AFRL/FMV) seeks:
–To engage in international cooperation regarding research development test and evaluation (RDT&E), activities which may lead to the development of miniaturized aerospace systems.
–To jointly research rapidly reconfigurable nanosat technologies to conduct R&D in miniaturized avionics components.
–To investigate PnP implementation and unification at an international level to include PnP ground prototyping, qualification of new methodologies for flight worthiness of nanosat components, and R&D of a flight worthy component.
*Bi-lateral Project Agreement (PA-TRDP-US-SW-AF-09-002).
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NAPA organization
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Space Plug-and-Play Avionics (SPA) In search of a standard approach for spacecraft
driver
USB interface chip
plug-and-playcomponent
“platform”
electronicdatasheetcomponent
App
liqué
Sens
or
Inte
rfac
e M
odul
e (A
SIM
)
Applique sensor interface module
“platform”
plug-and-playcomponent
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SPA – The technologies
Electronic Datasheets
Black box components
Self-organizing networks
Enhanced testability
Push-button toolflow
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“raw
de
vice”
RTU
SPA device
Building spacecraft with SPA: you’ll need
Computer (runs SDM and
“apps”) power
sync
RTU
SPA
router
components…
..at least one computer…
… and routers
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Connect together to form a spacecraft…RT
URadio
RTUPayload
OBDHHost RTU Battery
RTU ChargeReg.
RTU Guidance
RTUPayload
RTUPayload
RTU SolarPanel
Hub
RTU
Page 9Space Plug-and-Play Avionics (SPA) Making the Complex Simple through Architecture
PnPSat-1
CubeFlow Kit
PnP Panel
Responsive Space Testbed
TacSat-3Spaceflight
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AFRL PnPSat-1 assembly in 4 hours• Approx: 50 x 50 x 50 cm3• SPA‐SpaceWire (SPA‐S) network• Integrated harness in structural elements
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Very low data rate (< 400 Kb/s) SPA‐1 (since 2009), based on I2C
low data rate (< 12 Mb/s) SPA‐U
(since 2005)based on USB 1.1
high data rate (< 600 Mb/s)SPA‐S (since 2007)based on SpaceWire
Very high data rate >10 Gb/s“SPA‐O”
(Planned)
Number of components
Performance of com
pone
nts
One Size Doesn’t Fit All…
Implemented in US
Developed in NAPA
Ready for space
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One Size Doesn’t fit All - Simple Example• Spacecraft has 200 components
– “One Size Fits all” – 2000 W for interfaces. No good.– Four SPA levels – 65 W (5 x SPA-O, 10 x SPA-S, 30 x SPA-U, 155 x SPA-1) …. VAST SAVINGS!!! (~ 95%)
• Nanospacecraft need better SPA-interface–Smaller–Less weight–Lower power–Lower cost
Conclusion: Developing a Minimalistic SPA was a harmonization priority!
Conclusion: Developing a Minimalistic SPA was a harmonization priority!
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Minimizing Cost with Open Source• Space Plug and Play Avionics is conceived to use to the largest
extent possible open source which is well recognized and maintained.
• ÅAC ‘s Plug and Play avionics features the following Open Source tools:– Same tool chain for regular and Fault Tolerant processors– Soft core OpenRISC 1200 32 bit processor (RTU, RTU “lite”, µRTU)– Soft core PIC16F84 (nanoRTU)– GNU Project Debugger (GDB) (RTU, RTU “lite”, µRTU)– GNU Compiler Collection (GCC) (RTU, RTU “lite”, µRTU)– Linux Operating System (2.6) (RTU, RTU “lite”)– SourceBoost C compiler (nanoRTU) (license required for full
nanoRTU functionality)
• Flight hardware Fault Tolerant (FT) processors derived from open source– Soft core OpenRISC 1200-FT (fault tolerant enhanced by ÅAC)*– Soft core PIC16F84-FT (fault tolerant enhanced by ÅAC)*
* Fault tolerant (FT) versions are not provided as open source.
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Approach to Harmonized plug-and-play for nanosatellites
• Select an interface• Develop a generic plug-and-play protocol around it = ”mini-
PnP” (MP)– Open source– ITAR free
• Mini-PnP can be used for any system–When converted into space-capable form = ”SPA-1”
Page 15
Interface Selection• Examined SPI,I2C,SMBus, micro-wire, UART, RS-485, and
others– SPI – Good, fast, scalability problematic– I2C – Simple, now license-free, but lacking generic discovery /registration protocol– SMBus – Essentially I2C derivative, some undesirable constraints– Micro-Wire – Proprietary, no hopes to make rad-hard– UART – Simple and effective, but point-to-point– RS-485 – Multidrop, but lacking generic discovery
• We chose I2C– Need to develop additional protocol for address resolution– Possible to create a four-wire interface (two pins for I2C, two for power)
or two-wire version by modulating data on power (Transducers Bus).
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MP/SPA-1 message formatCommands (opcode) Responses (opcode)
Self test Status
Reset Data
Initialize xTEDS
Request version xTEDS & PID
Request xTEDS Version
Request data subscription Hello
Cancel data subscription
Power on
Power off
Command
Time at tone (SCET)
General call for registration
Update address
Ack
Not Ack
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Mini-PnP/SPA-1 Address resolution• All mini PnP devices have unique global identification (guid) • Implement address resolution by performing a ”general call”• All devices use 0x11 as an initial address• Devices become multi-master and ”walk up” address space until they find
an open spot and claim it
Mini‐PnP Host Mini‐PnP Host Mini‐PnP DeviceMini‐PnP Device
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Mini-PnP/SPA-1 Electronic Data Sheet (xTEDS*) registration
• Mechanism defined to permit the extraction of electronic datasheets from mini-PnP device
• Host parses xTEDS* and registers device services for use by other devices and applications
Mini‐PnP Host Mini‐PnP Host Mini‐PnP DeviceMini‐PnP Device
* XTEDS = eXtensible Transducer Electronic Datasheet
Page 19
Mini-PnP/SPA-1 Round Robin communication• Mini-PnP Implements a Command (”write”), Response (”read”), and
General Call as a continuous cycle using a non-weighted round-robin, visiting all known devices and looking for new ones
Mini‐PnP
Host
Mini‐PnP
Host
Mini‐PnP
Device
Mini‐PnP
Device
Mini‐PnP
Device
Mini‐PnP
Device
Mini‐PnP
Device
Mini‐PnP
Device
Page 20
Mini-PnP 2 wire (MP2) / Transducers Bus
• Innovation allow elimination of all wires except for power• Modulation of data on power allows I2C signals (SDA, SCL) to be superimposed
on power lines• Simple transceiver allows MP2 devices to convert to MP4 and vice versa for
systems and components as needed
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Three tier division – where mini-PnP/SPA-1 fits
ÅAC Avionics
products
Page 22
ÅAC 3-tier avionics products (1)
Feature RTU 2.0™ RTU ”lite”™ µRTU™ nanoRTU™
Processor architecture 19‐24 MHz32 bit RISC
DSPFPUMMU
19‐24 MHz32 bit RISC
DSPFPUMMU
19‐24 MHz32 bit RISC
DSP
16 MHzPIC16
Radiation protection EDAC, Parity,
Scrubber, TMREDAC, Parity,
Scrubber, TMREDAC, Parity,
Scrubber, TMREDAC, Parity,
TMR
Memory [instruction words] TBD 12 Mword 12 Mword 4 kword
PCB Dimensions [mm2]NMF facet size
70 x 701 NMF
34 x 70½ NMF
34 x 70½ NMF
34 x 34¼ NMF
Communication Ethernet (1)SpaceWire (4)USB Host (2)
I2C (6)CAN (1)UART (2)GPIO
Ethernet (1)USB Host (1)
I2C (4)UART (2)GPIO
SpaceWire (1)USB slave (1)
I2C (4)UART (2)GPIO
I2C (2)UART TTL (1)GPIO (12)
Average power [W] 3 1.2 1 0.25
AD/DA 8 x 12 bit 8 x 12 bit 8 x 12 bit 4 x 12 bit
OS Linux 2.6.34 Linux 2.6.34 Mem. Mapped Mem. Mapped
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ÅAC subsystems products (2)
Feature DPCU‐S DPCU‐U14 DPCU‐144 GNC MM
Description Distributed
Power Control
Unit (SPA‐S)
Distributed Power
Control Unit (SPA‐
U)
Distributed
Power Control
Unit (SPA‐1)
IMU + MGN
+Kalman filter
Non‐volatile
Mass
Memory
SPA interface nanoRTU nanoRTU nanoRTU µRTU µRTU
PCB Dimensions [mm2]NMF facet size
34 x 70½ NMF
34 x 34¼ NMF
34 x 34¼ NMF
34 x 70½ NMF
34 x 34¼ NMF
Radiation protection LCL LCL LCL ‐ EDAC
Capacity 4 x SPA‐S i/f3 A each
4 x SPA‐U i/f3 A each
4 x SPA‐1 i/f1 A each
MEMS GyroMEMS Accel.
Flash16 GByte
Power consumption [W] ~ 0.6 ~ 0.3 ~ 0.3 ~0.8 ~ 1.2
Extra 4 x SPA‐S 1 Upstream USB
port, 4
downstream
4 redundant
SPA‐1 ports‐
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User case (1), Plug ’n’ Play architecture• Example of medium performance distributed nanosatellite architecture based on SPA components
RS232
Payload
µRTU 312
GPS
Camera
DPU‐114 or DPCU‐144
DPU‐114 or DPCU‐144
RTU ”lite” If Operating System (OS) is
wanted
I2C bus A 400 kpbs RS232 nRTU 212
RS232 DRV
UART TTL
RS232 I2C bus B 400 kpbs
+5 V +5 V
+5 V
+5 V
64 MB RAM > 30 MB
Can be used as volatile FT Mass Memory
RS232
nRTU 212 RW
MTQ EPS
12 Dout (3.3V)
ACS Actuators
UHF Tx
VHF Rx nRTU 212
UART TTL
RS232
DPU‐114 or DPCU‐144
+5 V
I2C bus C 400 kpbs
SPARE
SPARE
SPARE
MGN RS422
MGN 4 Ain 2 Dout 5, 3.3 V ?
Backbone1.2 Mbps
Coarse SS
SS
nRTU 212
AIO board
6 Ain
4 Ain
SPI
ACS Sensors
nRTU 212
Simple board with AD (same as on nanoRTU) mapped on SPI
!! Each nanoRTU has 1 KB USER RAM
to buffer small Tx/Rx Packets
SPARE
SPARE
BAT heater
An Temp, Current Sens, etc.
Dout
Din Ain
RS232 Subsystem
nRTU 212
nRTU 212
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PnP Virtual Satellite Integration Equipment
Virtual Satellite Integration over internet with TCP-IP. Simulate or link plug-and-play subsystems together for cost efficient satellite integration
VSI interface: Ethernet T-base 10/100
Version 1 protocol support: SpaceWire, CAN, RS485, RS232
Version 2 protocol support: SpaceWire, USB 1.1, I2C, RS422, RS232
Internet /Intranet
PnP spacecraft
subsystem
Page 26
ÅAC nanosatellite offerings• QuadSat-PnP is offered together with OHB and University of Applied Sciences in Bremen.
Nanosatelliteplattforms
Nanosatellite Core components
Education
AvionicsAvionics PowerPower SPA/Plug’n’Play
training
SPA/Plug’n’Play
training
SPA/Plug’n’Play
educational kits
SPA/Plug’n’Play
educational kits
ThermalThermalQuadSat‐PnPQuadSat‐PnP
RTU 2.0RTU 2.0
RTU ”lite”RTU ”lite”
µRTUµRTU
PDU‐114PDU‐114
DPCU‐144DPCU‐144
PDU‐U14PDU‐U14
PDCU‐U14PDCU‐U14
GNCGNC
nanoRTUnanoRTU
NVM Mass
Memory
NVM Mass
Memory
IMU+MGNKalman
IMU+MGNKalman
ThermalSwitchThermalSwitch
PDCU‐SPDCU‐SVirtual Satellite
Integration
Virtual Satellite
Integration
Page 27
QuadSat-PnP 1 spacecraft details
Flight heritage from 10 previous flights (”RUBIN platform”)
”SPAready” (rapid integration with self describing subsystems)
Modular and scalable
4U QuadSat Formfactor , 25 x 25 x 20 cm
~15 W continous power
Weight < 15 kg
PSLV launch in H2 2011
Sun pointing stabilized (magnetorquers)
Intersatellite, S-band, and VHF data downlink
ÅAC miniaturized POL main payload
AFRL, NASA Ames, TNO payloads
Support from US DoD/ORS
Illustration of OHB QuadSat for Latvian
customer
Page 28
System design example (QuadSat-PnP)
Sa fe Mode ODBH
Intersatellite Link Unit
Orbcomm Antenna
Main Power Distribution Unit
MPDU
BA T String #1
BA T String #2
Sola r Arra y Str ing #1
Sola r Arra y String #2
SPA/Nomina l Mode ODBH
DPCU SPA/1
#1
DPCU SPA/1
#2
DPCU SPA/1
#3
(nanoRTU) + Exte rna l
AD
ALWAYS ON (LEVEL 0)
SPA Pow er State (LEV EL 1)
Payload Power State (LEVEL 3)
Payload Nomina l Power State (LEVEL 2)
MGN/ MTQ
(nano RTU PCB)
AIS receiver
VHF
S-band
Camera Mass Memory
Iridium Antenna
SPA-1
Power
SPA-U CAN
AIS Antenna
DPCU #1
SPA/U
DPCU #1
SPA/U
IMU
DHS-HKM
UART
Page 29
Conclusions
• The SPA Plug-and-play architecture offers a new model for rapidly and flexibly building spacecraft through intelligent modularity
• A joint US/Sweden program (”NAPA”) has developed improvements to SPA to allow simple spacecraft components to support plug-and-play
• The development of the generic minimalist protocol has been described• The mini-PnP protocol will be open source / ITAR free, but space adaptation of
mini-PnP (referred to as ”SPA-1”) results in ITAR restrictions (when performed in the US)
• AAC Microtec (Sweden) has created ITAR-free interface modules that implement mini-PnP (SPA-1), SPA-U, SPA-S in rad-tolerant form
• The existing Satellite Design Model (SDM) source code is ITAR• QuadSat-PnP platform has been presented
Page 30
Acknowledgments and Questions
• Configurable Space Microsystems Innovations & Applications Center (COSMIAC), Albuquerque, New Mexico
• Utah State University/Space Dynamics Laboratory, Logan, Utah• OHB System AG, Bremen, Germany• University of Applied Sciences, Bremen, Germany• Swedish National Space Board (SNSB)
• For more information, see http://pnp.aacmicrotec.com
