Fredrik Bruhn

QuadSat/PnP: A Space-Plug-and-play Architecture (SPA) Compliant Nanosatellite

The first nanospacecraft based completely on a “plug-and-play” model is described. QuadSat/PnP is a unique platform that brings together the concepts of legacy nanospacecraft and modern self-organizing networks of self-describing hardware and software components. New work in space plug-and-play avionics (SPA) pioneered in a US/Sweden collaboration have led to the extreme miniaturization of these functions in a form conducive to use in even the smallest spacecraft.

Introducing radiation tolerant heterogeneous computers for small satellites

This paper presents results and conclusions from design, manufacturing, and benchmarking of a heterogeneous computing low power fault tolerant computer, realized on an industrial Qseven® small form factor (SFF) platform. A heterogeneous computer in this context features multi-core processors (CPU), a graphical processing unit (GPU), and a field programmable gate array (FPGA). The x86 compatible CPU enables the use of vast amounts of commonly available software and operating systems, which can be used for space and harsh environments. The developed heterogeneous computer shares the same core architecture as game consoles such as Microsoft Xbox One and Sony Playstation 4 and has an aggregated computational performance in the TFLOP range. The processing power can be used for on-board intelligent data processing and higher degrees of autonomy in general. The module feature quad core 1.5 GHz 64 bit CPU (24 GFLOPs), 160 GPU shader cores (127 GFLOPs), and a 12 Mgate equivalent FPGA fabric with a safety critical ARM® Cortex-M3 MCU. Earlier space use applications of x86 processors have not been safety critical and were susceptible to radiation.

Real-Time Capabilities of HSA Compliant COTS Platforms

During recent years, the interest in using heterogeneous computing architecture in industrial applications has increased dramatically. These architectures provide the computational power that makes them attractive for many industrial applications. However, most of these existing heterogeneous architectures suffer from the following limitations: difficulties of heterogeneous parallel programming and high communication cost between the computing units. To overcome these disadvantages, several leading hardware manufacturers have formed the HSA Foundation to develop a new hardware architecture: Heterogeneous System Architecture (HSA). In this paper, we investigate the suitability of using HSA for real-time embedded systems. A preliminary experimental study has been conducted to measure massive computing power and timing predictability of HSA.

Architectural framework and toolflow concepts for rapidly composable wireless spacecraft

This paper provides a glimpse of work being done in a nearly decade-long joint US/Sweden and spacecraft research collaboration exploring rapid spacecraft design based on modular components whose simplicity and composability motivate the exploitation of modern design automation approaches and concepts that have been popularized in consumer and industrial online commerce. Modular systems are engineered to minimize tight couplings between components, with an aim of permitting interchangeability of elements and free composability to form many different possible system designs. Physical wiring often contributes to the complexity, and reducing or eliminating it aids in the objectives of modularity. In this paper, we consider an approach to create modular spacecraft, with a particular emphasis on cube satellites having a 6U form factor, based on a composition of “nearly wireless” elements. Since efficient power delivery remains problematic, our scheme permits the introduction of two terminals (analogous to residential wall outlets) for the sole purpose of power access. All other functions are delivered through a wireless network self organized based on a given collection of components necessary to form a particular spacecraft design. Panel structures can be prewired for power-only distribution, eliminating the need for custom wiring harnesses. In the proposed 6U Cubesat concept, a primary flat surface (~200mm × 300mm) substrate is the basis of a “dinner tray” convention. Modules are added to the pegboard-like “dinner tray” by plugging them in topside, forming a single unified planar interface for electrical, mechanical, and thermal integration. Electrical power blocks energize the substrate, processor modules provide wireless connection access points, and all other modules extract power from the strategically distributed contact points throughout the substrate. Once powered, these modules are networked through a “join and discovery” mechanism which provides a dynamically extensible application programming interface (API) expressed in the form of electronic data sheets. A sophisticated middleware layer (running on the same processing modules that provide the wireless “hotspots”) matches applications using a “brokerage” publish and subscribe mechanism. When the dependencies of each application is satisfied through the existence of suitable modules, the application is activated. The entire application suite is a hierarchy implemented as a direct acyclic graph (DAG) of these dependencies that when satisfied form a viable system (in this case a spacecraft) design. The implications of the method are profound in that it is possible to rapidly develop an virtually infinite variety of system designs given a sufficiently large collection of building block hardware and software applications. This paper describes a pushbutton toolflow (PBTF) motivated by concepts electronic design automation, only they are now extended to encompass satellite (or other system) designs. This pushbutton toolflow involves a configurator concept through which the user could negotiate (with relatively simple wizard like dialogs) a variety of viable spacecraft designs. The tool would access a multi-vendor “electronic store”, where prebuilt components and applications are marshaled into DAGs corresponding to buildable systems. The approach is analogous to a shopping cart metaphor, in which system cost and delivery times can be tracked based on the collection of dependencies formed by the selection of particular components need to satisfy design constraints. Documentation, including bill of materials, data sheets, and a full work breakdown structure can be produced as a byproduct. The toolflow itself could be extended to encompass automatic program generation and three-dimensional printing approaches to permit automated, customizable software and hardware generation (respectively), to complement the catalog of available components. The toolflow has other profound impacts, such as the ability to publish “recipes” (i.e., useful system representations) for use by other users, the ability to automatically coordinate communications (through a “space dialtone” concept) between orbiting platforms in ground station networks, and techniques that arrange for the construction and launch of these configurator produced spacecraft design by cooperating third-party networks.

Software architecture for next generation hyperparallel cyber-physical hardware platforms: challenges and opportunities

We present what is destined to become the de-facto standard for hardware platforms for next generation cyber-physical systems. Heterogeneous System Architecture (HSA) is an initiative to harmonize the industry around a common architecture which is easier to program and is an open standard defining the key interfaces for parallel computation. Since HSA is supported by virtually all major players in the silicon market we can conjecture that HSA, with its capabilities and quirks, will highly influence both the hardware and software for next generation cyber-physical systems. In this paper we describe HSA and discuss how its nature will influence architectures of system software and application software. Specifically, we believe that the system software needs to both leverage the hyperparallel nature of HSA while providing predictable and efficient resource allocation to different parallel activities. The application software, on the other hand, should be isolated from the complexity of the hardware architecture but yet be able to efficiently use the full potential of the hyperparallel nature of HSA.