NASA Office of Logic Design

A scientific study of the problems of digital engineering for space flight systems,
with a view to their practical solution.

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Interfaces and Standards

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Spacewire

SpaceWire Home Page

SpaceWire: Spacecraft onboard data-handling network

Steve Parkes^a, and Philippe Armbruster^b

^aSpace Technology Centre, University of Dundee, Dundee, DD1 4HN Scotland, UK
^bEuropean Space Research and Technology Centre (ESTEC), European Space Agency

Received 26 January 2009; revised 12 May 2009; accepted 21 May 2009. Available online 19 July 2009.

Abstract: The SpaceWire data-handling network is being used on many ESA, NASA and JAXA spacecraft and by other space agencies, research organisations and space industry across the world. SpaceWire is designed to connect together high data-rate sensors, processing units, memory sub-systems and the down link telemetry sub-system. It provides high-speed (2–200 Mbits/s), bi-directional, full-duplex, data links which connect the SpaceWire enabled equipment. Networks can be built to suit particular applications using point to point data links and routing switches. SpaceWire is supported by several radiation tolerant ASICs designed by or for ESA, NASA and JAXA, and extensive test and development equipment is available. This paper provides an introduction to SpaceWire aimed at project managers and system engineers. It describes how SpaceWire can be used to implement data-handling architectures matched to mission requirements and illustrates this with some examples. Finally an overview of the latest developments in SpaceWire is included.

Title, Authors, Reference	Abstract
MIL-STD-1553/1773 Basics
MIL-HDBK-1553A 1 November 1988	Abstract This document provides rationale and guidance on the use of requirements contained in MIL-STD-1553B, Aircraft Internal Time Division Command/Response Multiplex Data Bus.
Space Internet Workshop (SIW)	Description The Space Internet Workshop brings together mission planners, technologists, system designers, engineers, and scientists from the space community to enable transparent end-to-end network communications among space mission resources. Communications within and between the various space environments are included. This workshop in 2004 is fourth in the series to continue comprehensive discussions of cost-effective technical solutions for the design and engineering of mission communications. The goal is to foster dialog on current and near-term related activities for deploying Internet technologies for flight missions and identify critical technology development areas.
A Comparison of Bus Architectures for Safety-Critical Embedded Systems John Rushby NASA/CR-2003-212161, March 2003 Keywords: Certification; Integrated modular avionics; Fault tolerant bus_safetycritical_rushby_2002.pdf	Abstract: We describe and compare the architectures of four fault-tolerant, safety-critical buses with a view to deducing principles common to all of them, the main differences in their design choices, and the tradeoffs made. Two of the buses come from an avionics heritage, and two from automobiles, though all four strive for similar levels of reliability and assurance. The avionics buses considered are the Honeywell SAFEbus (the backplane data bus used in the Boeing 777 Airplane Information Management System) and the NASA SPIDER (an architecture being developed as a demonstrator for certification under the new DO-254 guidelines); the automobile buses considered are the TTTech Time-Triggered Architecture (TTA), recently adopted by Audi for automobile applications, and by Honeywell for avionics and aircraft control functions, and FlexRay, which is being developed by a consortium of BMW, DaimlerChrysler, Motorola, and Philips.
Avionics Data Buses: An Overview J-G Zhang, A. Pervez, and A.B. Sharma IEEE AESS Systems Magazine February 2003, pp. 18-22 zhang_2003	Abstract An overview of military avionics data buses and their applications, with the emphasis on optical fiber networking techniques. The evolution of military avionics data buses is discussed. The development trend actually reflects an increasing demand on such data buses, which requires the change from low-speed to high-speed transmissions, from single-rate to dual-rate operations, and from centralized control to distributed control. Recent progress in military avionics networks is described.
http://www.austriamicrosystems.com	Provides development capacity and Application Specific Standard Products (ASSP) for Bus Systems - Automotive
http://www.tttech.com	Time-Triggered Technology - Drive-by-Wire Technology
Test Methodology for Characterizing the SEE Sensitivity of a Commercial IEEE 1394 Serial Bus (FireWire) C. Seidleck, Raytheon; H. Kim, Jackson and Tull; S. Buchner, QSS/NASA Goddard Space Flight Center; P. W. Marshall, Consultant; K. LaBel, NASA Goddard Space Flight Center Presented at the 2002 IEEE NSREC Phoenix, AZ seidleck_nsrec_02.ppt	Abstract The SEE responses of two FireWire serial buses, based on the IEEE 1394 standard, were tested with heavy ions and protons. A unique approach to testing and categorizing the Single-Event Effects (SEEs) is presented.
1553Interpretation.pdf	Introduction Excerpt This document provides an explanation of each part of MIL-STD-1553 on a clause-by-clause basis. Each clause of the Standard is presented for completeness together with appropriate explanation or interpretation wherever necessary. The numbering of the clauses and figures in this document are compared to those in MIL-STD-1553 in Table 10.3.1. Although the Standard specifies a multiplex data bus for aerospace applications, it is by no means limited to these applications. MIL-STD-1553 has been widely accepted around the world in such unlikely places as the London underground and some factory locations. A brief summary of the requirements introduced by Notice 1 and Notice 2 to MIL-STD-1553 is given at the end of this Appendix.
MIL-STD-1553/1773 Basics	In recent years, the use of digital techniques in aircraft equipment has greatly increased, as have the number of avionics subsystems and the volume of data processed by them. Because analog point-to-point wire bundles are inefficient and cumbersome means of interconnecting the sensors, computers, actuators, indicators, and other equipment onboard the modern military vehicle, a serial digital multiplex data bus was developed. MIL-STD-1553 defines all aspects of the bus, therefore, many groups working with the military tri-services have chosen to adopt it. The 1553 multiplex data bus provides integrated, centralized system control and a standard interface for all equipment connected to the bus. The bus concept provides a means by which all bus traffic is available to be accessed with a single connection for testing and interfacing with the system. The standard defines operation of a serial data bus that interconnects multiple devices via a twisted, shielded pair of wires. The system implements a command-response format.
RS-422 Basics	Specifying compliance to RS-422 only establishes that the signal between the specified devices will be compatible. It does not indicate that the signal functions or operations between the two devices are compatible. The RS-422 standard only defines the characteristic requirements for the balanced line drivers and receivers. It does not specify one specific connector, signal names or operations. RS-422 interfaces are typically used when the data rate or distance criteria cannot be met with RS-232. The RS-422 standard allows for operation of up to 10 receivers from a single transmitter. The standard does not define operations of multiple tristated transmitters on a link.
The Role of Standards in Lower-Cost Digital Spacecraft Avionics Douglas W. Caldwell Jet Propulsion Laboraory AIAA-95-1019-CP A Collection of Technical Papers AIAA Computing in Aerospace 10 March 28-30, 1995 San Antonio, TX pp. 559-568	Abstract The use of standard interfaces could result in large savings for the aerospace industry. This paper discusses the philosophy, applicability, and implications of using interface standards in spacecraft applications. It is argued that, while there are some negatives associated with their use, standards should be liberally applied to all aspects of spacecraft avionics because they ultimately reduce end-to-end system costs.
VALIDATION OF A 1553 IP Philippe Mercier¹, Eric Clavé¹ , Luis Baguéna² , Dominique De Saint Roman³ ¹ADV Engineering, PT Du Canal ²Alcatel Space Industries ³TEMIC MHS Proceedings European Space Components Conference ESCCONN 2000 21-23 March 2000 ESTEC, Noordwijk, The Netherlands pp. 173-175	Abstract Considering the increasing complexity of ASICs development, the use of IP will become more and more frequent in the next future. At the moment the use of IP is bridled by the non confidence in the validation process of these blocks, which lead IP customers to conduct a new validation on the product before its integration into their ASIC. This validation effort can be very important and take a lot of time if bugs are detected and shall be corrected by IP provider. To avoid this, the IP provider shall perform on its product an extensive validation that results shall be available to customers and has to provide an efficient support guaranteeing that any problem could be fixed quickly. This paper presents the validation approach followed by ADV Engineering for its 1553 macrocell validation.

Standards

NASA TECHNICAL STANDARDS PROGRAM

Welcome to the NASA Technical Standards Program website. This website is sponsored by the NASA Chief Engineer as a common access point for technical standards developed by NASA and others adopted for use on NASA programs. Adopted standards are those Types of Standards Products developed by other Government and non-Government national and international standards developing organizations. The primary emphasis is placed on the use of "preferred"technical standards that have been approved by NASA Chief Engineer as recommended by the NASA Engineering Standards Steering Council, based on a consensus of the NASA Centers.

NASA-developed Technical Standards listed on the Web-site are available on-line in full-text without charge to all users. DOD/FED and CCSDS full-text technical standards products are available without charge to all users. A listing of NASA adopted and pending adoption non-Government (Voluntary Consensus Standards) is also given. Some (AIAA, IEEE, ASTM, & SAE) of these non-Government voluntary consensus developed technical standards are available in full-text to users in the "nasa.gov" domain without charge. All other non-Government technical standards listed are available for purchase from the respective standards developing organization. This applies to all users including those within the "nasa.gov" domain.

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