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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) Page 2
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 Page 3
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). Page 4
NAPA organization Page 5 Space Plug-and-Play Avionics (SPA) In search of a standard approach for spacecraft
“platform” “platform”
plug-and-play plug-and-play component component electronic component driver (ASIM) datasheet Appliqué Sensor Interface Module
USB interface chip Applique sensor interface module Page 6 SPA – The technologies
Electronic Datasheets
Black box components
Self-organizing networks
Enhanced testability
Push-button toolflow Page 7
Building spacecraft with SPA: you’ll need
SPA device
RTU “raw components… device”
Computer (runs SDM and
sync ..at least one computer… “apps”) power SPA RTU … and routers router Page 8
Connect together to form a spacecraft…
OBDH RTU Host RTU Battery Radio RTU RTU Charge Reg. Payload RTU
Hub RTU Payload Solar RTU Panel
Payload RTU RTU Guidance Space Plug-and-Play Avionics (SPA) Page 9 Making the Complex Simple through Architecture
Responsive Space Testbed
PnPSat-1
PnP Panel
TacSat-3 CubeFlow Kit Spaceflight Page 10
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… Page 11
Very high data rate >10 Gb/s “SPA‐O” (Planned) high data rate (< 600 Mb/s) SPA‐S (since 2007) Implemented in US based on SpaceWire Developed in NAPA components space
low data rate of
for (< 12 Mb/s) SPA‐U
(since 2005)
Ready based on USB 1.1
Performance Very low data rate (< 400 Kb/s) SPA‐1 (since 2009), based on I2C
Number of components Page 12
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! Page 13
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. Page 14
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). Page 16
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 Page 17 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 Page 18
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 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 Mini‐PnP Mini‐PnP Mini‐PnP Host Device Device 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 Page 21
Three tier division – where mini-PnP/SPA-1 fits
ÅAC Avionics products
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ÅAC 3-tier avionics products (1)
Feature RTU 2.0™ RTU ”lite”™ µRTU™ nanoRTU™
Processor architecture 19‐24 MHz 19‐24 MHz 19‐24 MHz 16 MHz 32 bit RISC 32 bit RISC 32 bit RISC PIC16 DSP DSP DSP FPU FPU MMU MMU Radiation protection EDAC, Parity, EDAC, Parity, EDAC, Parity, EDAC, Parity, Scrubber, TMR Scrubber, TMR Scrubber, TMR TMR Memory [instruction words] TBD 12 Mword 12 Mword 4 kword
PCB Dimensions [mm2] 70 x 70 34 x 70 34 x 70 34 x 34 NMF facet size 1 NMF ½NMF ½NMF ¼NMF Communication Ethernet (1) Ethernet (1) SpaceWire (1) I2C (2) SpaceWire (4) USB Host (1) USB slave (1) UART TTL (1) USB Host (2) I2C (4) I2C (4) GPIO (12) I2C (6) UART (2) UART (2) CAN (1) GPIO GPIO UART (2) GPIO 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 Page 23
ÅAC subsystems products (2)
Feature DPCU‐S DPCU‐U14 DPCU‐144 GNC MM
Description Distributed Distributed Power Distributed IMU + MGN Non‐volatile Power Control Control Unit (SPA‐ Power Control + Mass Unit (SPA‐S) U) Unit (SPA‐1) Kalman filter Memory
SPA interface nanoRTU nanoRTU nanoRTU µRTU µRTU
PCB Dimensions [mm2] 34 x 70 34 x 34 34 x 34 34 x 70 34 x 34 NMF facet size ½NMF ¼NMF ¼NMF ½NMF ¼NMF Radiation protection LCL LCL LCL ‐ EDAC
Capacity 4 x SPA‐S i/f 4 x SPA‐U i/f 4 x SPA‐1 i/f MEMS Gyro Flash 3 A each 3 A each 1 A each MEMS Accel. 16 GByte Power consumption [W] ~ 0.6 ~ 0.3 ~ 0.3 ~0.8 ~ 1.2
Extra 4 x SPA‐S 1 Upstream USB 4 redundant ‐ port, 4 SPA‐1 ports downstream
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User case (1), Plug ’n’ Play architecture • Example of medium performance distributed nanosatellite architecture based on SPA components
GPS RS232 DRV +5 V RS232 +5 V I2C bus A +5 V nRTU 212 Payload RS232 RS232 400 kpbs DPU‐114 or Subsystem µRTU 312 RS232 DPCU‐144 nRTU 212 Camera UART TTL
RTU ”lite” I2C bus B nRTU 212 RS232 RW If Operating 400 kpbs 64 MB RAM System (OS) is 12 Dout MTQ > 30 MB wanted (3.3V) EPS Can be used ACS Actuators as volatile FT +5 V Mass Memory DPU‐114 or SPARE DPCU‐144
MGN nRTU 212 RS422 I2C bus C 4 Ain Backbone 400 kpbs Simple board MGN with AD (same SPI 2 Dout 1.2 Mbps as on nanoRTU) 5, 3.3 V ? mapped on SPI 6 Ain AIO Coarse SS SPARE board SPARE +5 V 4 Ain SS DPU‐114 or ACS Sensors DPCU‐144 Din An Temp, Current Sens, nRTU 212 Ain etc.
Dout BAT heater
!! Each nanoRTU nRTU 212 UHF Tx has 1 KB USER RAM UART TTL to buffer small Tx/Rx Packets nRTU 212 VHF Rx RS232
SPARE SPARE 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 Nanosatellite Education plattforms Core components
SPA/Plug’n’Play QuadSat‐PnP Avionics Power GNC Thermal training
RTU 2.0 PDU‐114 IMU+MGN Thermal Kalman Switch SPA/Plug’n’Play educational kits RTU ”lite” DPCU‐144
µRTU PDU‐U14
nanoRTU PDCU‐U14
Virtual Satellite NVM Mass PDCU‐S Integration Memory
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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 Illustration of OHB QuadSat for Latvian . Weight < 15 kg customer
. 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
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System design example (QuadSat-PnP)
Orb com m An tenn a Iridium Antenna Mass Camera Memory VHF
Safe Mode ODBH SPA/Nominal Mode UART Intersatellite ODBH Link Unit S-band
DPCU #1 DH S- HK M SPA/U DPCU SPA/1 IMU #1 DPCU #1 SPA/U BA T Str ing # 1 DPCU SPA/1 Sola r Arra y #2 String #1 Main Power Distribution Unit MPDU DPCU Sola r Arra y SPA/1 String #2 #3
BA T Str ing # 2 (nanoRTU) + External MGN/ AD MTQ (nanoRTU PCB)
ALWAYS ON (LEVEL 0) Power SPA-1 SPA Power State (LEV EL 1) SPA-U CAN Nominal Power State (LEVEL 2) Payload AIS receiver AIS Antenna
Payload Power State (LEVEL 3) 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