ISO 18427:2013

Space data and information transfer systems — Spacecraft Onboard Interface Services — Subnetwork Synchronization Service

ISO 18427:2013 is one of a family of documents specifying the SOIS-compliant services to be provided by onboard subnetworks. ISO 18427:2013 defines services and service interfaces provided by the SOIS Subnetwork Synchronisation Service. Its scope is to specify the service only and not to specify methods of providing the service over a variety of onboard data links. ISO 18427:2013 conforms to the principles set out in the Spacecraft Onboard Interface Services Green Book and is intended to be applied together with it. The protocols which provide this service are to be documented for individual links, and this can be in the purview of individual missions, agencies, or CCSDS, depending on future circumstances.

Systèmes de transfert des informations et données spatiales — Services d'interfaces à bord des véhicules spatiaux — Service de synchronisation par sous-réseau

General Information

• Status: Published
• Publication Date: 29-May-2013
• ICS: 49.140 - Space systems and operations
• Technical Committee: ISO/TC 20/SC 13 - Space data and information transfer systems
• Drafting Committee: ISO/TC 20/SC 13 - Space data and information transfer systems
• Current Stage: 9060 - Close of review
• Completion Date: 04-Mar-2029

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 18427
First edition
2013-06-01
Space data and information transfer
systems — Spacecraft Onboard Interface
Services — Subnetwork Synchronization
Service
Systèmes de transfert des informations et données spatiales —
Services d'interfaces à bord des véhicules spatiaux — Service de
synchronisation par sous-réseau

Reference number
©
ISO 2013
©  ISO 2013
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ii © ISO 2013 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of
ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2. www.iso.org/directives
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent
rights identified during the development of the document will be in the Introduction and/or on the ISO list of
patent declarations received. www.iso.org/patents
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
ISO 18427 was prepared by the Consultative Committee for Space Data Systems (CCSDS) (as
CCSDS 853.0-M-1, December 2009) and was adopted (without modifications except those stated in Clause 2
of this International Standard) by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee
SC 13, Space data and information transfer systems.

INTERNATIONAL STANDARD ISO 18427:2013(E)

Space data and information transfer systems — Spacecraft
Onboard Interface Services — Subnetwork Synchronization
Service
1 Scope
This International Standard is one of a family of documents specifying the SOIS-compliant services to be
provided by onboard subnetworks.
The purpose of this International Standard is to define services and service interfaces provided by the SOIS
Subnetwork Synchronisation Service. Its scope is to specify the service only and not to specify methods of
providing the service over a variety of onboard data links.
This International Standard conforms to the principles set out in the Spacecraft Onboard Interface Services
Green Book and is intended to be applied together with it. The protocols which provide this service are to be
documented for individual links, and this can be in the purview of individual missions, agencies, or CCSDS,
depending on future circumstances.
The scope and field of application are furthermore detailed in subclause 1.2 of the enclosed CCSDS
publication.
2 Requirements
Requirements are the technical recommendations made in the following publication (reproduced on the
following pages), which is adopted as an International Standard:
CCSDS 853.0-M-1, December 2009, Spacecraft Onboard Interface Services — Subnetwork Synchronization
Service.
For the purposes of international standardization, the modifications outlined below shall apply to the specific
clauses and paragraphs of publication CCSDS 853.0-M-1.
Pages i to v
This part is information which is relevant to the CCSDS publication only.
3 Revision of publication CCSDS 853.0-M-1
It has been agreed with the Consultative Committee for Space Data Systems that Subcommittee
ISO/TC 20/SC 13 will be consulted in the event of any revision or amendment of publication CCSDS 853.0-
M-1. To this end, NASA will act as a liaison body between CCSDS and ISO.

(Blank page)
2 © ISO 2013 – All rights reserved

Recommendation for Space Data System Practices
SPACECRAFT ONBOARD
INTERFACE SERVICES—
SUBNETWORK
SYNCHRONISATION SERVICE
RECOMMENDED PRACTICE
CCSDS 853.0-M-1
MAGENTA BOOK
December 2009
AUTHORITY
Issue: Recommended Practice, Issue 1
Date: December 2009
Location: Washington, DC, USA
This document has been approved for publication by the Management Council of the
Consultative Committee for Space Data Systems (CCSDS) and represents the consensus
technical agreement of the participating CCSDS Member Agencies. The procedure for
review and authorization of CCSDS documents is detailed in the Procedures Manual for the
Consultative Committee for Space Data Systems, and the record of Agency participation in
the authorization of this document can be obtained from the CCSDS Secretariat at the
address below.
This document is published and maintained by:

CCSDS Secretariat
Space Communications and Navigation Office, 7L70
Space Operations Mission Directorate
NASA Headquarters
Washington, DC 20546-0001, USA
CCSDS RECOMMENDED PRACTICE FOR SOIS SUBNETWORK SYNCHRONISATION SERVICE
STATEMENT OF INTENT
The Consultative Committee for Space Data Systems (CCSDS) is an organization officially
established by the management of its members. The Committee meets periodically to address
data systems problems that are common to all participants, and to formulate sound technical
solutions to these problems. Inasmuch as participation in the CCSDS is completely
voluntary, the results of Committee actions are termed Recommendations and are not in
themselves considered binding on any Agency.
CCSDS Recommendations take two forms: Recommended Standards that are prescriptive
and are the formal vehicles by which CCSDS Agencies create the standards that specify how
elements of their space mission support infrastructure shall operate and interoperate with
others; and Recommended Practices that are more descriptive in nature and are intended to
provide general guidance about how to approach a particular problem associated with space
mission support. This Recommended Practice is issued by, and represents the consensus of,
the CCSDS members. Endorsement of this Recommended Practice is entirely voluntary
and does not imply a commitment by any Agency or organization to implement its
recommendations in a prescriptive sense.
No later than five years from its date of issuance, this Recommended Practice will be
reviewed by the CCSDS to determine whether it should: (1) remain in effect without change;
(2) be changed to reflect the impact of new technologies, new requirements, or new
directions; or (3) be retired or cancelled.
In those instances when a new version of a Recommended Practice is issued, existing
CCSDS-related member Practices and implementations are not negated or deemed to be non-
CCSDS compatible. It is the responsibility of each member to determine when such Practices
or implementations are to be modified. Each member is, however, strongly encouraged to
direct planning for its new Practices and implementations towards the later version of the
Recommended Practice.
CCSDS 853.0-M-1 Page ii December 2009
FOREWORD
This document is a technical Recommended Practice for use in developing flight and
ground systems for space missions and has been prepared by the Consultative Committee
for Space Data Systems (CCSDS). The Subnetwork Synchronisation Service described
herein is intended for missions that are cross-supported between Agencies of the CCSDS, in
the framework of the Spacecraft Onboard Interface Services (SOIS) CCSDS area.
This Recommended Practice specifies a service to be used by space missions to
synchronise subnetwork users to subnetwork-maintained time or asynchronous subnetwork
events. The SOIS Synchronisation Service is provided by data link-specific mechanisms
within the subnetwork layers. The service interface is present only in the data system
invoking the service. The SOIS Subnetwork Synchronisation Service provides a common
service interface regardless of the particular type of data link being used for communication.
Through the process of normal evolution, it is expected that expansion, deletion, or
modification of this document may occur. This Recommended Practice is therefore subject
to CCSDS document management and change control procedures, which are defined in the
Procedures Manual for the Consultative Committee for Space Data Systems. Current
versions of CCSDS documents are maintained at the CCSDS Web site:
http://www.ccsds.org/
Questions relating to the contents or status of this document should be addressed to the
CCSDS Secretariat at the address indicated on page i.
CCSDS RECOMMENDED PRACTICE FOR SOIS SUBNETWORK SYNCHRONISATION SERVICE
At time of publication, the active Member and Observer Agencies of the CCSDS were:

Member Agencies
– Agenzia Spaziale Italiana (ASI)/Italy.
– British National Space Centre (BNSC)/United Kingdom.
– Canadian Space Agency (CSA)/Canada.
– Centre National d’Etudes Spatiales (CNES)/France.
– China National Space Administration (CNSA)/People’s Republic of China.
– Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)/Germany.
– European Space Agency (ESA)/Europe.
– Russian Federal Space Agency (RFSA)/Russian Federation.
– Instituto Nacional de Pesquisas Espaciais (INPE)/Brazil.
– Japan Aerospace Exploration Agency (JAXA)/Japan.
– National Aeronautics and Space Administration (NASA)/USA.

Observer Agencies
– Austrian Space Agency (ASA)/Austria.
– Belgian Federal Science Policy Office (BFSPO)/Belgium.
– Central Research Institute of Machine Building (TsNIIMash)/Russian Federation.
– Centro Tecnico Aeroespacial (CTA)/Brazil.
– Chinese Academy of Sciences (CAS)/China.
– Chinese Academy of Space Technology (CAST)/China.
– Commonwealth Scientific and Industrial Research Organization (CSIRO)/Australia.
– CSIR Satellite Applications Centre (CSIR)/Republic of South Africa.
– Danish National Space Center (DNSC)/Denmark.
– European Organization for the Exploitation of Meteorological Satellites
(EUMETSAT)/Europe.
– European Telecommunications Satellite Organization (EUTELSAT)/Europe.
– Geo-Informatics and Space Technology Development Agency (GISTDA)/Thailand.
– Hellenic National Space Committee (HNSC)/Greece.
– Indian Space Research Organization (ISRO)/India.
– Institute of Space Research (IKI)/Russian Federation.
– KFKI Research Institute for Particle & Nuclear Physics (KFKI)/Hungary.
– Korea Aerospace Research Institute (KARI)/Korea.
– Ministry of Communications (MOC)/Israel.
– National Institute of Information and Communications Technology (NICT)/Japan.
– National Oceanic and Atmospheric Administration (NOAA)/USA.
– National Space Organization (NSPO)/Chinese Taipei.
– Naval Center for Space Technology (NCST)/USA.
– Scientific and Technological Research Council of Turkey (TUBITAK)/Turkey.
– Space and Upper Atmosphere Research Commission (SUPARCO)/Pakistan.
– Swedish Space Corporation (SSC)/Sweden.
– United States Geological Survey (USGS)/USA.
CCSDS 853.0-M-1 Page iv December 2009
DOCUMENT CONTROL
Document Title Date Status
CCSDS Spacecraft Onboard Interface December Original issue
853.0-M-1 Services—Subnetwork 2009
Synchronisation Service,
Recommended Practice, Issue 1
CCSDS RECOMMENDED PRACTICE FOR SOIS SUBNETWORK SYNCHRONISATION SERVICE
CONTENTS
Section Page
1  INTRODUCTION . 1-1

1.1  PURPOSE AND SCOPE OF THIS DOCUMENT . 1-1
1.2  APPLICABILITY . 1-1
1.3  RATIONALE . 1-1
1.4  DOCUMENT STRUCTURE . 1-1
1.5  CONVENTIONS AND DEFINITIONS. 1-2
1.6  DOCUMENT NOMENCLATURE . 1-4
1.7  REFERENCES . 1-4

2  OVERVIEW . 2-1

2.1  FUNCTION . 2-1
2.2  CONTEXT . 2-1
2.3  ASSUMPTIONS . 2-2
...