Leveraging the Openness and Modularity of RISC-V in Space

Abstract

This paper proposes a roadmap to address present and future needs in space systems with RISC-V processors. RISC-V is an open and modular instruction set architecture, which is rapidly growing in popularity in terrestrial applications. To satisfy different applications with contrasting requirements in satellite data systems, four different types of processors are identified: 1) low-area/low-power microcontrollers, 2) on-board computers, 3) general-purpose processors for payloads, and 4) enhanced payload processors for artificial intelligence. Several solutions based on RISC-V are proposed for each of these types of processors and compared with proprietary commercial-off-the-shelf and spacegrade solutions. An extensive analysis of the results available from literature is conducted to show that RISC-V has the potential to solve such a wide range of needs. This paper will also show the unprecedented number of open-source implementations and models that were developed in a relative short time on a single instruction set architecture. Future space systems could benefit from many of those developments, and this work identifies and highlights what is still missing to satisfy the specific needs of processors for space, especially in terms of fault tolerance and technology readiness level.

A Survey on RISC-V-Based Machine Learning Ecosystem

“…Since 2010, the open RISC-V ISA has gained great popularity and nowadays, due to a critical mass of open-source hardware implementations, based on RISC-V, it is being demonstrated in a plethora of application domains [13][14][15][16]. Moreover, chip designs based on the RISC-V ISA, are of particular interest to the small and medium-sized enterprises (SMEs) and startups, due to non-existent license fees for proprietary intellectual property (IP) core blocks [17].…”

A comparative survey of open-source application-class RISC-V processor implementations

“…This makes RISC-V particularly interesting for special purpose and niche applications. For instance, RISC-V is a promising architecture for the space domain with stringent reliability requirements [24,25].…”

On-Board Decision Making in Space with Deep Neural Networks and RISC-V Vector Processors

“…2) High-performance proprietary commercial-off-the-shelf (COTS) processors employed in terrestrial applications are being proposed [9]. Although they can achieve higher-order magnitude performance compared with state-of-the-art space processors [10], they come with a large "cost of ownership" to avoid losses in terms of dependability [11], and possible restrictions on its usage and knowledge of internal behavior [4].…”

“…The second goal of this paper is to show that a fourth approach can be followed, as performances of space processors can be substantially improved with data-level parallelism (DLP) to achieve performance of the same order of magnitude of high-performance terrestrial processors for DNNs. To do this, we develop in more detail the study of the RISC-V processors needed to enable on-board decision making (OBDM) carried out in [4], focusing on the preliminary design of a RISC-V vector processor specifically for space applications. This preliminary design is intended to serve as a baseline for future works, during the Very High Speed Integrated Circuit Hardware Description Language (VHDL) implementation of a RISC-V vector processor for space applications based on the NOEL-V platform (developed by Cobham Gaisler) [14].…”

“…RISC-V is an instruction set architecture (ISA) that is rapidly growing in popularity in both terrestrial and space applications [4]. Its main characteristics are simplicity, openness (being a free and open standard allows open-source implementations), and modularity (i.e., composed of a base ISA and many optional ISA extensions).…”