"Reconfigurable Processing Building Blocks for Spacecraft"

Joseph R. Marshall - Senior Principal Systems Engineer
9300 Wellington Road - Manassas, VA 20112

Introduction (1/2 page)

Reconfigurability is a key element to extracting the most from any spacecraft or spacecraft subsystem. It allows systems to become more autonomous, maximizes their usage once deployed, and delays obsolescence by allowing new uses of the spaceborne asset, often in ways not envisioned by its creators. In the past, reconfigurability has been mostly present in the software side of the spaceborne systems. Hardware consisted of standard and hard-wired application specific components, and short of a shuttle repair mission, one could not reconfigure it. Advancements in field programmable devices now offer increased flexibility to the user. For example, BAE SYSTEMS continues to expand a set of reconfigurable processing building blocks centered on its RAD750(tm) processor products, standard form factors and interfaces. These blocks may be utilized to create various processing architectures, be extended to other I/O and be reprogrammed and reconfigured at any or all of the software, interface or FPGA levels. A significant infrastructure has been developed that is centered on making it easier for the application to utilize. To this end, communication, control and low level management interfaces were defined and implemented within the building blocks that allowed the user more time to develop and integrate the mission of the system. In creating these system building blocks for spacecraft payloads, we developed comprehensive verification and validation approaches that not only completes the development of the building blocks but also assure higher level integration and provide a testbed for future use. Our goal continues to be to create an OS for hardware where it is as easy to change some or all of the hardware functions as it has been to create software functions in previous systems.

Related Work and References

  1. Joseph R. Marshall et.al., "(Advancing) Reconfigurable Processing Subsystems in Spaceborne Applications", 2003 and 2004 IEEE Aerospace Conference Proceedings, March 2003 and 2004.
  2. Paul Graham et. al., "Reconfigurable Computing in Space: From Current Technology to Reconfigurable Systems-On-a-Chip, 2003 IEEE Aerospace Conference Proceedings, March 2003.
  3. Jason A Soloff et. al., "Development of a Software Radio Based Reconfigurable Intersatellite Crosslink Testbed", 2003 Military and Aerospace Programmable Logic Device (MAPLD) International Conference Record, September 2003.
  4. Robert H Klenke et. al., "Implementing a Rad-Hard Compact PCI bus-based system using Actel FPGAs", 2003 Military and Aerospace Programmable Logic Device (MAPLD) International Conference, Poster P32, September 2003.
  5. Joseph R. Marshall and Richard W. Berger, "A Processor Solution for the Second Century of Powered Space Flight", 19th Digital Avionics Systems Conference Proceedings, October 2000.
  6. Randel C. Blue and Gary S. Bolotin, "X2000 Advanced Avionices Project Development of a New Generation of Avionics for Space Applications", 2003 IEEE Aerospace Conference Proceedings, March 2003.
  7. Glenn Parker Rakow et. al., "NASA / BAE SYSTEMS SpaceWire Efforts", International SpaceWire Seminar (ISWS) 2003 Proceedings, November 2003.
  8. Joseph R. Marshall and Dale Langston, "Embedding COTS Processors into Fault Tolerant Space Applications", Computing in Aerospace 10 Conference Proceedings, March, 1995.
  9. Joseph R. Marshall, "A Reconfigurable Digital Processing System for Space", 20th Digital Avionics Systems Conference, October 2001.

Key Elements of Paper and Conclusions

The space industry is continuing to expand state of the art processing technologies: processors, ASICs, FPGAs, support software, interconnects, memories and other building blocks that may be utilized for future reconfigurable systems. As these technologies evolve, it will become easier to create reconfigurable systems. For example, at the base of many reconfigurable systems are RAM-based or fused-based circuits. Fuse-based circuits provide non-volatility but are not reconfigurable in space. RAM-based circuits provide the ability to remotely reconfigure the system in the field. New memory technologies, such as BAE SYSTEMS Chalcogenide memory which is currently under development, is being applied to provide the advantages of both instant reconfiguration and non-volatility in a single device. This high density, non-volatile technology utilized in commercial re-writeable CDs, may be applied to space applications and reconfigurable processing systems as standalone devices similar to today's FPGAs. In addition, Chalcogenide-based FPGA elements may be inserted into ASICs and / or Systems on a Chip technologies to provide a reconfigurable component mixed with high performance elements that may adapt to the latest interface, algorithms, or emerging standards.

Interfaces today are anything but stable. Various standards and companies are competing to create the next major interface among candidates utilizing serial, short parallel and switched fabrics. By utilizing reconfigurable components in the key interface locations, it will be possible for a system to either adapt to the latest interface or add a proprietary interface expending minimum development time and cost. This is especially important in space systems when control, design and interface decisions remain embedded in systems for a long time, the best example being MIL-STD-1553B. There is significantly more change and growth on the data transport side, most recently featuring serial interfaces such as IEEE 1394 and 1355 and which can benefit more from reconfigurability to match the latest enhancements to a standard above the physical layer. Clearly, as technology continues to evolve, reconfigurable systems will become the norm in the today's and future space systems.

Future reconfigurable technology building blocks and systems built from them need to improve in these areas of processing technologies, reconfigurable circuits, memory elements and interfaces. We will focus on potential needs and improvements in this paper.

Conclusion: Reconfigurable processing systems are needed for many space missions and applications and the first designs and products are beginning to appear. High speed interfaces such as SpaceWire and FireWire are LVDS interface technologies that will provide the interconnects between processing elements. Technology is not yet ideal for this type of system though it is improving yearly. BAE SYSTEMS has a high performance reconfigurable computer product and architecture for applying it to applications in concert with our other products. When new non-volatile memory and FPGA products become available such as BAE SYSTEMS C-RAM and C-FPGA, power and complexity should be able to be reduced as today's card products become tomorrow's chips enabling even more powerful space processing applications.


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