Page 1
Introducing a Low Cost and High Performing
Interoperable Satellite Platform based on Plugand-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-andplay 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
“platform”
“platform”
plug-and-play
component
driver
USB interface chip
component
Appliqué Sensor
Interface Module
(ASIM)
plug-and-play
component
electronic
datasheet
Applique sensor interface module
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SPA – The technologies
Electronic Datasheets
Black box components
Self-organizing networks
Enhanced testability
Push-button toolflow
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Building spacecraft with SPA: you’ll need
RTU
RTU
SPA
router
sync
Computer (runs SDM and “apps”)
components…
power
“raw device”
SPA device
..at least one computer…
… and routers
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Connect together to form a spacecraft…
RTU
OBDH
Host
RTU
RTU
Battery
Radio
RTU
Payload
RTU
RTU
Hub
RTU
Payload
RTU
RTU
Payload
Charge
Reg.
Guidance
Solar
Panel
Space Plug-and-Play Avionics (SPA)
Making the Complex Simple through Architecture
Responsive Space Testbed
PnPSat-1
PnP Panel
CubeFlow Kit
TacSat-3
Spaceflight
Page 9
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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
One Size Doesn’t Fit All…
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high data rate (< 600 Mb/s)
SPA‐S (since 2007)
based on SpaceWire
Ready for space
Performance of components
Very high data rate >10 Gb/s
“SPA‐O” (Planned)
Implemented in US
Developed in NAPA
low data rate (< 12 Mb/s) SPA‐U (since 2005)
based on USB 1.1
Very low data rate (< 400 Kb/s) SPA‐1 (since 2009), based on I2C
Number of components
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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!
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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 = ”miniPnP” (MP)
– Open source
– ITAR free
• Mini-PnP can be used for any system
–When converted into space-capable form = ”SPA-1”
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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 format
Commands (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 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 Device
* XTEDS = eXtensible Transducer Electronic Datasheet
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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 Device
Mini‐PnP Device
Mini‐PnP Device
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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
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ÅAC 3-tier avionics products (1)
Feature
Processor architecture
Radiation protection
Memory [instruction words]
PCB Dimensions [mm2]
NMF facet size
Communication
Average power [W]
AD/DA
OS
RTU 2.0™
RTU ”lite”™
µRTU™
nanoRTU™
19‐24 MHz
32 bit RISC
DSP
FPU
MMU
19‐24 MHz
32 bit RISC
DSP
FPU
MMU
19‐24 MHz
32 bit RISC
DSP
16 MHz
PIC16
EDAC, Parity, Scrubber, TMR
EDAC, Parity, Scrubber, TMR
EDAC, Parity, Scrubber, TMR
EDAC, Parity, TMR
TBD
12 Mword
12 Mword
4 kword
70 x 70
1 NMF
34 x 70
½ NMF
34 x 70
½ NMF
34 x 34
¼ NMF
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)
3
1.2
1
0.25
8 x 12 bit
8 x 12 bit
8 x 12 bit
4 x 12 bit
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
nanoRTU
nanoRTU
nanoRTU
µRTU
µRTU
34 x 70
½ NMF
34 x 34
¼ NMF
34 x 34
¼ NMF
34 x 70
½ NMF
34 x 34
¼ NMF
LCL
LCL
LCL
‐
EDAC
4 x SPA‐S i/f
3 A each
4 x SPA‐U i/f
3 A each
4 x SPA‐1 i/f
1 A each
MEMS Gyro
MEMS Accel.
Flash
16 GByte
~ 0.6
~ 0.3
~ 0.3
~0.8
~ 1.2 4 x SPA‐S
1 Upstream USB port, 4 downstream
4 redundant SPA‐1 ports
‐
SPA interface
PCB Dimensions [mm2]
NMF facet size
Radiation protection
Capacity
Power consumption [W]
Extra
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User case (1), Plug ’n’ Play architecture
•
Example of medium performance distributed nanosatellite architecture based on SPA components
RS232 DRV GPS RS232 Subsystem RS232 RS232 +5 V +5 V µRTU 312 +5 V I2C bus A 400 kpbs nRTU 212
DPU‐114 or DPCU‐144 RS232 nRTU 212
64 MB RAM > 30 MB Can be used as volatile FT Mass Memory I2C bus B 400 kpbs RTU ”lite” If Operating System (OS) is wanted UART TTL RS232 nRTU 212
12 Dout (3.3V)
ACS Actuators
+5 V
DPU‐114 or DPCU‐144 I2C bus C 400 kpbs Simple board with AD (same as on nanoRTU) mapped on SPI RS422 4 Ain 2 Dout 5, 3.3 V ? SPI AIO board SPARE
SPARE +5 V
DPU‐114 or DPCU‐144 RW MTQ EPS 6 Ain MGN MGN Coarse SS 4 Ain SS Din Ain An Temp, Current Sens, etc.
ACS Sensors nRTU 212
Dout !! Each nanoRTU has 1 KB USER RAM to buffer small Tx/Rx Packets Camera SPARE
nRTU 212
Backbone
1.2 Mbps
Payload nRTU 212
nRTU 212
SPARE SPARE
UART TTL
RS232 BAT heater UHF Tx VHF Rx Page 25
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
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ÅAC nanosatellite offerings
• QuadSat-PnP is offered together with OHB and University of Applied Sciences in Bremen.
Nanosatellite
plattforms
QuadSat‐PnP
Virtual Satellite Integration
Nanosatellite Core components
Education
Avionics
Power
GNC
Thermal
RTU 2.0
PDU‐114
IMU+MGN
Kalman
Thermal
Switch
RTU ”lite”
DPCU‐144
µRTU
PDU‐U14
nanoRTU
PDCU‐U14
NVM Mass Memory
PDCU‐S
SPA/Plug’n’Play training
SPA/Plug’n’Play educational kits
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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
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System design example (QuadSat-PnP)
Orbcomm Antenna
Iridium Antenna
Sa fe Mode
ODBH
Intersatellite
Link Unit
UART
Mass
Memory
S-band
DPCU
#1
SPA/U
DPCU
SPA/1
#1
Sola r Arra y
String #1
Sola r Arra y
String #2
BA T String #2
IMU
DPCU
#1
SPA/U
DPCU
SPA/1
#2
Main Power
Distribution Unit
MPDU
DPCU
SPA/1
#3
(nanoRTU)
+ Exte rna l
AD
MGN/
MTQ
(nano RTU
PCB)
AL WAYS ON (LEVEL 0)
SPA Pow er State (LEV EL 1)
Power
SPA-1
SPA-U
CAN
Nomina l Power State (LEVEL 2)
Payload Power State (LEVEL 3)
VHF
SPA/Nomina l Mode
ODBH
DH SHK M
BA T String #1
Camera
Payload
AIS receiver
AIS Antenna
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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