ISO 19389:2014

Space data and information transfer systems - Conjunction data message

ISO 19389:2014 specifies a standard message format for use in exchanging spacecraft conjunction information between originators of Conjunction Assessments (CAs) and satellite owner/operators and other authorized parties. Such exchanges are used to inform satellite owner/operators of conjunctions between objects in space to enable consistent warning by different organizations employing diverse CA techniques. ISO 19389:2014 will: facilitate interoperability and enable consistent warning between data originators who supply CA and the satellite owner/operators who use it; facilitate automation for the CA processes; and provide critical information to enable timely CA decisions. This document includes requirements and criteria that the message format has been designed to meet (see Annex D). Also included are informative descriptions of conjunction information pertinent to performing CA (see Annex E). ISO 19389:2014 is applicable to satellite operations in all environments in which close approaches and collisions among satellites are concerns. It contains the specification for a Conjunction Data Message (CDM) designed for applications involving conjunction information interchange between originators of CAs and recipients. Conjunction information includes data types such as miss distance, probability of collision, Time of Closest Approach (TCA), and closest approach relative position and velocity. Further information describing the conjunction information contained in this message can be found in section 3 and Annex E. This message is suited for exchanges that involve manual or automated interaction. The attributes of a CDM make it suitable for use in machine-to-machine interfaces because of the large amount of data typically present. The CDM is self contained. However, additional information could be specified in an Interface Control Document (ICD) written jointly by the service originator and recipients. It is desirable that CDM originators maintain consistency with respect to the optional keywords provided in their implementations; i.e., it is desirable that the composition of the CDMs provided not change on a frequent basis. ISO 19389:2014 is applicable only to the message format and content, but not to its transmission nor to the algorithms used to produce the data within. The method of transmitting the message between exchange partners is beyond the scope of this document and could be specified in an ICD. The methods used to predict conjunctions and calculate the probability of collision, and the definition of the conjunction assessment accuracy underlying a particular CDM, are also outside the scope of ISO 19389:2014 (the interested reader can consult references in Annex F).

Systèmes de transfert des données et informations spatiales — Message de données de conjonction

General Information

• Status: Published
• Publication Date: 22-Jun-2014
• 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-2030

Relations

• Consolidated By: ISO/TS 15877-7:2018 - Plastics piping systems for hot and cold water installations - Chlorinated poly(vinyl chloride) (PVC-C) - Part 7: Guidance for the assessment of conformity
• Effective Date: 06-Jun-2022

Overview

ISO 19389:2014 - Space data and information transfer systems: Conjunction data message defines a standardized message format for exchanging spacecraft conjunction information between Conjunction Assessment (CA) originators and satellite owner/operators (and other authorized parties). The standard (adopted from CCSDS 508.0‑B‑1) specifies a self-contained Conjunction Data Message (CDM) designed to support consistent warnings, interoperability, and automation across diverse CA providers and users. It applies to satellite operations in any environment where close approaches and collision risk are a concern.

Key topics and technical requirements

• CDM structure and content: The specification describes CDM header, metadata and data elements - including fields for miss distance, probability of collision, Time of Closest Approach (TCA), and relative position and velocity at closest approach.
• Representations: The CDM is defined in both key‑value notation (KVN) and XML formats to support human‑readable and machine‑readable exchanges.
• Self‑contained messages: CDMs are designed to be complete messages; optional keywords exist but originators are encouraged to maintain consistency in their use.
• Machine‑to‑machine suitability: The message attributes support automated interfaces and bulk data handling for CA workflows.
• Requirements & criteria: Annex D (informative) summarizes the requirements and criteria the message format was designed to meet; Annex E provides informative descriptions of conjunction information; Annex F lists references for CA algorithms and accuracy definitions.
• Scope limits: ISO 19389:2014 standardizes only message format and content - it does not prescribe transmission methods, nor the algorithms used to generate collision probabilities or compute conjunctions.

Practical applications and users

Who uses ISO 19389:2014

• Satellite owner/operators needing consistent, actionable conjunction alerts.
• Conjunction assessment service providers who produce and share CA data.
• Mission operations centers integrating automated collision‑avoidance decision pipelines.
• Ground system integrators implementing machine‑to‑machine CDM interfaces (KVN/XML).
• International and multi‑agency programs requiring interoperable CA data exchange across organizations.

Practical benefits

• Enables consistent warning and decision‑making across diverse CA techniques.
• Facilitates automation of CA processing, alerting, and collision‑avoidance planning.
• Provides a common basis for Interface Control Documents (ICDs) between originators and recipients.

Related standards

• Based on CCSDS 508.0‑B‑1 (Conjunction Data Message).
• ISO adoption references other CCSDS/ISO work (see Annexes and Clause 2 for cross‑references, e.g., equivalence notes for CCSDS 301.0‑B‑4 / ISO 11104 and CCSDS 505.0‑B‑1 / ISO 17107).

Keywords: ISO 19389:2014, Conjunction Data Message, CDM, conjunction assessment, probability of collision, Time of Closest Approach, satellite operator, interoperability, machine‑to‑machine, XML, KVN, CCSDS 508.0‑B‑1.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 19389
First edition
2014-07-01
Space data and information transfer
systems — Conjunction data message
Systèmes de transfert des données et informations spatiales —
Message de données conjointes
Reference number
©
ISO 2014
©  ISO 2014
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any
means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission.
Permission can be requested from either ISO at the address below or ISO’s member body in the country of the requester.
ISO copyright office
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Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
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ii © ISO 2014 – 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 (see 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 (see 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.
For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as
well as information about ISO's adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the
following URL: Foreword - Supplementary information
ISO 19389 was prepared by the Consultative Committee for Space Data Systems (CCSDS) (as CCSDS 508.0-B-1,
June 2013) 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 19389:2014(E)

Space data and information transfer systems — Conjunction
data message
1 Scope
This Conjunction Data Message (CDM) International Standard specifies a standard message format for use in
exchanging spacecraft conjunction information between originators of Conjunction Assessments (CAs) and
satellite owner/operators and other authorized parties. Such exchanges are used to inform satellite
owner/operators of conjunctions between objects in space to enable consistent warning by different
organizations employing diverse CA techniques.
This International Standard will:
a) facilitate interoperability and enable consistent warning between data originators who supply CA and the
satellite owner/operators who use it;
b) facilitate automation for the CA processes; and
c) provide critical information to enable timely CA decisions.
This document includes requirements and criteria that the message format has been designed to meet (see
Annex D). Also included are informative descriptions of conjunction information pertinent to performing CA
(see Annex E).
This International Standard is applicable to satellite operations in all environments in which close approaches
and collisions among satellites are concerns. It contains the specification for a CDM designed for applications
involving conjunction information interchange between originators of CAs and recipients. Conjunction
information includes data types such as miss distance, probability of collision, Time of Closest Approach
(TCA), and closest approach relative position and velocity. Further information describing the conjunction
information contained in this message can be found in section 3 and Annex E.
This message is suited for exchanges that involve manual or automated interaction. The attributes of a CDM
make it suitable for use in machine-to-machine interfaces because of the large amount of data typically
present. The CDM is self contained. However, additional information could be specified in an Interface Control
Document (ICD) written jointly by the service originator and recipients.
It is desirable that CDM originators maintain consistency with respect to the optional keywords provided in
their implementations; i.e., it is desirable that the composition of the CDMs provided not change on a frequent
basis.
This International Standard is applicable only to the message format and content, but not to its transmission
nor to the algorithms used to produce the data within. The method of transmitting the message between
exchange partners is beyond the scope of this document and could be specified in an ICD.
The methods used to predict conjunctions and calculate the probability of collision, and the definition of the
conjunction assessment accuracy underlying a particular CDM, are also outside the scope of this International
Standard (the interested reader can consult references in Annex F).

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 508.0-B-1, June 2013, Conjunction Data Message
For the purposes of international standardization, the modifications outlined below shall apply to the specific
clauses and paragraphs of publication CCSDS 508.0-B-1.
Pages i to vi
This part is information which is relevant to the CCSDS publication only.
Page 1-5
Add the following information to the reference indicated:
[5] Document CCSDS 301.0-B-4, November 2010, is equivalent to ISO 11104:2011.
[6] Document CCSDS 505.0-B-1, December 2010, is equivalent to ISO 17107:2011.
3 Revision of publication CCSDS 508.0-B-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 508.0-B-
1. To this end, NASA will act as a liaison body between CCSDS and ISO.
2 © ISO 2014 – All rights reserved

Recommendation for Space Data System Standards
CONJUNCTION
DATA MESSAGE
RECOMMENDED STANDARD
CCSDS 508.0-B-1
BLUE BOOK
June 2013
CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES
AUTHORITY
Issue: Recommended Standard, Issue 1
Date: June 2013
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 Organization and Processes for
the Consultative Committee for Space Data Systems (CCSDS A02.1-Y-3), 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 508.0-B-1 Page i June 2013

CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES
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 Recommended Standards and are
not considered binding on any Agency.
This Recommended Standard is issued by, and represents the consensus of, the CCSDS
members. Endorsement of this Recommendation is entirely voluntary. Endorsement,
however, indicates the following understandings:
o Whenever a member establishes a CCSDS-related standard, this standard will be in
accord with the relevant Recommended Standard. Establishing such a standard
does not preclude other provisions which a member may develop.
o Whenever a member establishes a CCSDS-related standard, that member will
provide other CCSDS members with the following information:
-- The standard itself.
-- The anticipated date of initial operational capability.
-- The anticipated duration of operational service.
o Specific service arrangements shall be made via memoranda of agreement. Neither
this Recommended Standard nor any ensuing standard is a substitute for a
memorandum of agreement.
No later than three years from its date of issuance, this Recommended Standard 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 canceled.
In those instances when a new version of a Recommended Standard is issued, existing
CCSDS-related member standards and implementations are not negated or deemed to be
non-CCSDS compatible. It is the responsibility of each member to determine when such
standards or implementations are to be modified. Each member is, however, strongly
encouraged to direct planning for its new standards and implementations towards the later
version of the Recommended Standard.
CCSDS 508.0-B-1 Page ii June 2013

CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES
FOREWORD
This document is a Recommended Standard for Conjunction Data Messages (CDMs) and has
been prepared by the CCSDS. The CDM described in this Recommended Standard is the
baseline concept for conjunction information interchange applications between interested
parties.
This Recommended Standard establishes a common framework and provides a common
basis for the format of conjunction information exchange between originators of conjunction
assessment data and satellite owner/operators. It allows implementing organizations within
each conjunction assessment originator to proceed coherently with the development of
compatible derived standards for the flight and ground systems that are within their
cognizance. Derived Agency standards can implement only a subset of the optional features
allowed by the Recommended Standard and can incorporate features not addressed by this
Recommended Standard.
Attention is drawn to the possibility that some of the elements of this document may be the
subject of patent rights. CCSDS shall not be held responsible for identifying any or all such
patent rights.
Through the process of normal evolution, it is expected that expansion, deletion, or
modification of this document may occur. This Recommended Standard is therefore subject
to CCSDS document management and change control procedures, which are defined in
Organization and Processes for the Consultative Committee for Space Data Systems
(CCSDS A02.1-Y-3). 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 508.0-B-1 Page iii June 2013

CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES
At time of publication, the active Member and Observer Agencies of the CCSDS were:
Member Agencies
– Agenzia Spaziale Italiana (ASI)/Italy.
– 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.
– Federal Space Agency (FSA)/Russian Federation.
– Instituto Nacional de Pesquisas Espaciais (INPE)/Brazil.
– Japan Aerospace Exploration Agency (JAXA)/Japan.
– National Aeronautics and Space Administration (NASA)/USA.
– UK Space Agency/United Kingdom.
Observer Agencies
– Austrian Space Agency (ASA)/Austria.
– Belgian Federal Science Policy Office (BFSPO)/Belgium.
– Central Research Institute of Machine Building (TsNIIMash)/Russian Federation.
– China Satellite Launch and Tracking Control General, Beijing Institute of Tracking
and Telecommunications Technology (CLTC/BITTT)/China.
– 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.
– Departamento de Ciência e Tecnologia Aeroespacial (DCTA)/Brazil.
– 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 Agency of the Republic of Kazakhstan (NSARK)/Kazakhstan.
– 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 508.0-B-1 Page iv June 2013

CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES
DOCUMENT CONTROL
Document Title Date Status
CCSDS Conjunction Data Message, June 2013 Current issue
508.0-B-1 Recommended Standard, Issue 1

CCSDS 508.0-B-1 Page v June 2013

CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES
CONTENTS
Section Page
1 INTRODUCTION . 1-1

1.1 PURPOSE AND SCOPE . 1-1
1.2 APPLICABILITY . 1-1
1.3 DOCUMENT STRUCTURE . 1-2
1.4 CONVENTIONS AND DEFINITIONS. 1-2
1.5 REFERENCES . 1-4

2 OVERVIEW . 2-1

2.1 GENERAL . 2-1
2.2 CDM BASIC CONTENT . 2-1

3 CDM CONTENT/STRUCTURE IN KVN . 3-1

3.1 GENERAL . 3-1
3.2 CDM HEADER . 3-1
3.3 CDM RELATIVE METADATA/DATA . 3-2
3.4 CDM METADATA . 3-4
3.5 CDM DATA . 3-7
3.6 DISCUSSION—CDM/KVN EXAMPLES . 3-11

4 CDM CONTENT/STRUCTURE IN XML . 4-1

4.1 DISCUSSION—THE CDM/XML SCHEMA . 4-1
4.2 CDM/XML BASIC STRUCTURE . 4-1
4.3 CONSTRUCTING A CDM/XML INSTANCE . 4-2
4.4 DISCUSSION—CDM/XML EXAMPLE . 4-6

5 CDM DATA IN GENERAL . 5-1

5.1 OVERVIEW . 5-1
5.2 RULES THAT APPLY IN KVN AND XML . 5-1

6 CDM SYNTAX . 6-1

6.1 OVERVIEW . 6-1
6.2 COMMON CDM SYNTAX . 6-1
6.3 THE CDM IN KVN . 6-2
6.4 THE CDM IN XML . 6-5

CCSDS 508.0-B-1 Page vi June 2013

CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES
CONTENTS (continued)
Section Page
ANNEX A IMPLEMENTATION CONFORMANCE STATEMENT
PROFORMA (NORMATIVE) . A-1
ANNEX B SECURITY, SANA, AND PATENT CONSIDERATIONS
(INFORMATIVE) .B-1
ANNEX C ABBREVIATIONS AND ACRONYMS (INFORMATIVE) . C-1
ANNEX D RATIONALE AND REQUIREMENTS FOR CONJUNCTION
DATA MESSAGES (INFORMATIVE) . D-1
ANNEX E CONJUNCTION INFORMATION
DESCRIPTION (INFORMATIVE) .E-1
ANNEX F INFORMATIVE REFERENCES (INFORMATIVE) . F-1
Figure
4-1 CDM XML Basic Structure . 4-1
E-1 Definition of the RTN and TVN Coordinate Frames . E-2

Table
3-1 CDM KVN Header . 3-2
3-2 CDM KVN Relative Metadata/Data . 3-2
3-3 CDM KVN Metadata . 3-4
3-4 CDM KVN Data . 3-8
4-1 Relation of KVN Logical Blocks to Special CDM/XML Tags . 4-5
4-2 Another Special CDM/XML Tag . 4-5
6-1 Example XML Keyword Tags with Specified Units . 6-6
D-1 Primary Requirements . D-2
D-2 Desirable Characteristics . D-4

CCSDS 508.0-B-1 Page vii June 2013

CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES
1 INTRODUCTION
1.1 PURPOSE AND SCOPE
This Conjunction Data Message (CDM) Recommended Standard specifies a standard
message format for use in exchanging spacecraft conjunction information between
originators of Conjunction Assessments (CAs) and satellite owner/operators and other
authorized parties. Such exchanges are used to inform satellite owner/operators of
conjunctions between objects in space to enable consistent warning by different
organizations employing diverse CA techniques.
This Recommended Standard will:
a) facilitate interoperability and enable consistent warning between data originators who
supply CA and the satellite owner/operators who use it;
b) facilitate automation for the CA processes; and
c) provide critical information to enable timely CA decisions.
This document includes requirements and criteria that the message format has been designed
to meet (see annex D). Also included are informative descriptions of conjunction information
pertinent to performing CA (see annex E).
1.2 APPLICABILITY
This Recommended Standard is applicable to satellite operations in all environments in
which close approaches and collisions among satellites are concerns. It contains the
specification for a CDM designed for applications involving conjunction information
interchange between originators of CAs and recipients. Conjunction information includes
data types such as miss distance, probability of collision, Time of Closest Approach (TCA),
and closest approach relative position and velocity. Further information describing the
conjunction information contained in this message can be found in section 3 and annex E.
This message is suited for exchanges that involve manual or automated interaction. The
attributes of a CDM make it suitable for use in machine-to-machine interfaces because of the
large amount of data typically present. The CDM is self contained. However, additional
information could be specified in an Interface Control Document (ICD) written jointly by the
service originator and recipients.
It is desirable that CDM originators maintain consistency with respect to the optional
keywords provided in their implementations; i.e., it is desirable that the composition of the
CDMs provided not change on a frequent basis.
This Recommended Standard is applicable only to the message format and content, but not to
its transmission nor to the algorithms used to produce the data within. The method of
CCSDS 508.0-B-1 Page 1-1 June 2013

CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES
transmitting the message between exchange partners is beyond the scope of this document
and could be specified in an ICD.
The methods used to predict conjunctions and calculate the probability of collision, and the
definition of the conjunction assessment accuracy underlying a particular CDM, are also
outside the scope of this Recommended Standard (the interested reader can consult
references in annex F).
1.3 DOCUMENT STRUCTURE
Section 2 provides a brief overview of the CCSDS-recommended CDM.
Section 3 provides details about the structure and content of the CDM in ‘Keyword = Value
Notation’ (KVN).
Section 4 provides details about the structure and content of the CDM in eXtensible Markup
Language (XML).
Section 5 addresses the CDM data in general.
Section 6 discusses the syntax considerations of the CDM.
Annex A contains an Implementation Conformance Statement (ICS) proforma that may be
used by implementers to compactly describe their implementations.
Annex B provides information on security, the Space Assigned Numbers Authority (SANA),
and patent-related information.
Annex C is a list of abbreviations and acronyms applicable to the CDM.
Annex D provides rationale and requirements for the CDM Recommended Standard.
Annex E provides a description of the CA information contained in the CDM.
Annex F provides informative references.
1.4 CONVENTIONS AND DEFINITIONS
1.4.1 NOTATION
1.4.1.1 Unit Notations
The following conventions for unit notations apply throughout this Recommended Standard.
Insofar as possible, an effort has been made to use units that are part of the International
System of Units (SI); units are either SI base units, SI derived units, or units outside the SI
that are accepted for use with the SI (see reference [1]). The units used within this document
are as follows:
CCSDS 508.0-B-1 Page 1-2 June 2013

CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES
– km: kilometers;
– m: meters;
– d: days, 86400 SI seconds;
– s: SI seconds;
– kg: kilograms;
– W: watts;
– %: percent.
1.4.1.2 General
The following notational conventions are used in this document:
a) multiplication of units is denoted with a single asterisk ‘*’ (e.g., ‘kg*s’);
b) exponents of units are denoted with a double asterisk ‘**’ (e.g., m = m**2);
c) division of units is denoted with a single forward slash ‘/’ (e.g., m/s).
1.4.2 NOMENCLATURE
1.4.2.1 General
The CDM contains information about a conjunction between two space objects (hereafter
referred to as ‘Object1’ and ‘Object2’).
1.4.2.2 Normative Text
The following conventions apply for the normative specifications in this Recommended
Standard:
a) the words ‘shall’ and ‘must’ imply a binding and verifiable specification;
b) the word ‘should’ implies an optional, but desirable, specification;
c) the word ‘may’ implies an optional specification;
d) the words ‘is’, ‘are’, and ‘will’ imply statements of fact.
NOTE – These conventions do not imply constraints on diction in text that is clearly
informative in nature.
CCSDS 508.0-B-1 Page 1-3 June 2013

CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES
1.4.2.3 Informative Text
In the normative sections of this document (sections 3-6), informative text is set off from the
normative specifications either in notes or under one of the following subsection headings:
– Overview;
– Discussion.
1.4.3 OTHER CONVENTIONS
1.4.3.1 Terminology
In this document, the term ‘ASCII’ is used generically to refer to the text character set
defined in reference [2]. The terms ‘N/A’ and ‘n/a’ are defined to mean ‘not available’ or
‘not applicable’.
1.4.3.2 Orthography
The following terms define orthographic conventions for XML notation in this
Recommended Standard:
CamelCase. A style of capitalization in which the initial characters of concatenated words
are capitalized, as in CamelCase.
lowerCamelCase. A variant of CamelCase in which the first character of a character string
formed from concatenated words is lowercase, as in lowerCamelCase. In the case of a
character string consisting of only a single word, only lowercase characters are used.
1.5 REFERENCES
The following publications contain provisions which, through reference in this text,
constitute provisions of this Recommended Standard. At the time of publication, the editions
indicated were valid. All publications are subject to revision, and users of this
Recommended Standard are encouraged to investigate the possibility of applying the most
recent editions of the publications indicated below. The CCSDS Secretariat maintains a
register of currently valid CCSDS publications.
[1] The International System of Units (SI). 8th ed. Sèvres, France: BIPM, 2006.
[2] Information Technology—8-Bit Single-Byte Coded Graphic Character Sets—Part 1:
Latin Alphabet No. 1. International Standard, ISO/IEC 8859-1:1998. Geneva: ISO,
1998.
[3] Henry S. Thompson, et al., eds. XML Schema Part 1: Structures. 2nd ed. W3C
Recommendation. N.p.: W3C, October 2004.
CCSDS 508.0-B-1 Page 1-4 June 2013

CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES
[4] Paul V. Biron and Ashok Malhotra, eds. XML Schema Part 2: Datatypes. 2nd ed.
W3C Recommendation. N.p.: W3C, October 2004.
[5] Time Code Formats. Recommendation for Space Data System Standards, CCSDS
301.0-B-4. Blue Book. Issue 4. Washington, D.C.: CCSDS, November 2010.
[6] XML Specification for Navigation Data Messages. Recommendation for Space Data
System Standards, CCSDS 505.0-B-1. Blue Book. Issue 1. Washington, D.C.:
CCSDS, December 2010.
CCSDS 508.0-B-1 Page 1-5 June 2013

CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES
2 OVERVIEW
2.1 GENERAL
This section provides a high-level overview of the CCSDS-recommended CDM, a message
format designed to facilitate standardized exchange of conjunction information between
originators of CA data and satellite owner/operators.
2.2 CDM BASIC CONTENT
The CDM is ASCII format encoded either in plain text or XML (see references [2], [3], and
[4]). This CDM document describes a KVN-formatted message as well as an XML-formatted
message (it is desirable that an ICD specify which of these formats will be exchanged).
The CDM contains information about a single conjunction between Object1 and Object2. It
contains
– Object1/Object2 positions/velocities at TCA with respect to one of a small set of
widely used reference frames (ITRF, GCRF—see reference [F11], EME2000);
– Object1/Object2 covariances at TCA with respect to an object centered reference
frame;
– the relative position/velocity of Object2 with respect to an Object1 centered reference
frame;
– information relevant to how all the above data was determined.
This information is used by satellite owner/operators to evaluate the risk of a conjunction and
plan maneuvers if warranted by that agency/organization. Where possible, the CDM is
consistent with other CCSDS Navigation Data Messages (NDMs). Similar tables have been
used to describe header, metadata, and data information. Common keywords have been used
in order to minimize duplication and confusion (e.g., CREATION_DATE, ORIGINATOR,
OBJECT_NAME, INTERNATIONAL_DESIGNATOR, etc.).

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CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES
3 CDM CONTENT/STRUCTURE IN KVN
3.1 GENERAL
3.1.1 The CDM in KVN shall consist of digital data represented as ASCII text lines. The
lines constituting a CDM shall be represented as a combination of the following:
a) a header;
b) relative metadata/data (metadata/data describing relative relationships between
Object1 and Object2);
c) metadata (data about how Object1 and Object2 data were created);
d) data (for both Object1 and Object2); and
e) optional comments (explanatory information).
NOTES
1 KVN messages contain one keyword per line (see 6.3.1.4).
2 The order of keywords in the KVN representation is fixed by this Recommended
Standard (see 6.3.1.9).
3.1.2 The CDM shall be plain text consisting of CA data for a single conjunction event. It
shall be easily readable by both humans and computers.
3.1.3 The method of exchanging CDMs shall be decided on a case-by-case basis by the
participating parties and should be documented in an ICD.
3.2 CDM HEADER
The CDM header shall consist of the KVN elements defined in table 3-1, which specifies for
each KVN header item:
a) the keyword to be used;
b) a short description of the item;
c) examples of allowed values; and
d) whether the item is obligatory or optional.
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CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES
Table 3-1: CDM KVN Header
Keyword Description Example of Values Obligatory
CCSDS_CDM_VERS Format version in the form of ‘x.y’, 1.0 Yes
where ‘y’ is incremented for corrections 2.0
and minor changes, and ‘x’ is
incremented for major changes.
COMMENT (See 6.3.4 for formatting rules.) COMMENT This is a No
comment
CREATION_DATE Message creation date/time in 2010-03-12T22:31:12.000 Yes
Coordinated Universal Time (UTC). 2010-071T22:31:12.000
(See 6.3.2.6 for formatting rules.)
ORIGINATOR Creating agency or owner/operator JSPOC, ESA_ESAC, Yes
(value should be registered in SANA). CNES, NASA-JPL, SDC
(See 5.2.9 for formatting rules.)
MESSAGE_FOR Spacecraft name(s) for which the CDM SPOT, ENVISAT, No
is provided. IRIDIUM, INTELSAT
MESSAGE_ID ID that uniquely identifies a message 201113719185 Yes
from a given originator. The format and ABC-12_34
content of the message identifier value
are at the discretion of the originator.
(See 5.2.9 for formatting rules.)
3.3 CDM RELATIVE METADATA/DATA
The CDM relative metadata/data shall consist of the KVN elements defined in table 3-2,
which specifies for each KVN relative metadata/data item:
a) the keyword to be used;
b) a short description of the item;
c) the units to be used if applicable; and
d) whether the item is obligatory or optional.
Table 3-2: CDM KVN Relative Metadata/Data
Keyword Description Units Obligatory
COMMENT (See 6.3.4 for formatting rules.) n/a No
TCA The date and time in UTC of the closest n/a Yes
approach. (See 6.3.2.6 for formatting rules.)
MISS_DISTANCE The norm of the relative position vector. It m Yes
indicates how close the two objects are at
TCA. Data type = double.
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CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES
Keyword Description Units Obligatory
RELATIVE_SPEED The norm of the relative velocity vector. It m/s No
indicates how fast the two objects are moving
relative to each other at TCA. Data type =
double.
RELATIVE_POSITION_R      The R component of Object2’s position m No
relative to Object1’s position in the Radial,
Transverse, and Normal (RTN) coordinate
frame. (See annex E for definition.) Data type
= double.
RELATIVE_POSITION_T      The T component of Object2’s position relative m No
to Object1’s position in the RTN coordinate
frame. (See annex E for definition.) Data type
= double.
RELATIVE_POSITION_N     The N component of Object2’s position m No
relative to Object1’s position in the RTN
coordinate frame. (See annex E for definition.)
Data type = double.
RELATIVE_VELOCITY_R      The R component of Object2’s velocity relative m/s No
to Object1’s velocity in the RTN coordinate
frame. (See annex E for definition.) Data type
= double.
RELATIVE_VELOCITY_T      The T component of Object2’s velocity relative m/s No
to Object1’s velocity in the RTN coordinate
frame. (See annex E for definition.) Data type
= double.
RELATIVE_VELOCITY_N     The N component of Object2’s velocity relative m/s No
to Object1’s velocity in the RTN coordinate
frame. (See annex E for definition.) Data type
= double.
START_SCREEN_PERIOD The start time in UTC of the screening period n/a No
for the conjunction assessment. (See 6.3.2.6
for formatting rules.)
STOP_SCREEN_PERIOD The stop time in UTC of the screening period n/a No
for the conjunction assessment. (See 6.3.2.6
for formatting rules.)
SCREEN_VOLUME_FRAME Name of the Object1 centered reference frame n/a No
in which the screening volume data are given.
Available options are RTN and Transverse,
Velocity, and Normal (TVN). (See annex E for
definition.)
SCREEN_VOLUME_SHAPE Shape of the screening volume: ELLIPSOID or n/a No
BOX.
SCREEN_VOLUME_X The R or T (depending on if RTN or TVN is m No
selected) component size of the screening
volume in the SCREEN_VOLUME_FRAME.
Data type = double.
SCREEN_VOLUME_Y The T or V (depending on if RTN or TVN is m No
selected) component size of the screening
volume in the SCREEN_VOLUME_FRAME.
Data type = double.
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CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES
Keyword Description Units Obligatory
SCREEN_VOLUME_Z The N component size of the screening m No
volume in the SCREEN_VOLUME_FRAME.
Data type = double.
SCREEN_ENTRY_TIME The time in UTC when Object2 enters the n/a No
screening volume. (See 6.3.2.6 for formatting
rules.)
SCREEN_EXIT_TIME The time in UTC when Object2 exits the n/a No
screening volume. (See 6.3.2.6 for formatting
rules.)
COLLISION_PROBABILITY The probability (denoted ‘p’ where n/a No
0.0<=p<=1.0), that Object1 and Object2 will
collide. Data type = double.
COLLISION_PROBABILITY_METHOD The method that was used to calculate the n/a No
collision probability. (See annex E for
definition.)
3.4 CDM METADATA
The CDM metadata shall consist of the KVN elements defined in table 3-3, which specifies
for each KVN metadata item:
a) the keyword to be used;
b) a short description of the item;
c) normative values or examples of allowed values;
d) whether the ‘Normative Values/Examples’ column contains normative values (N) or
examples of allowed values (E) for the item; and
e) whether the item is obligatory or optional.
NOTE – Table 3-3 and table 3-4 will be used to define both Object1 and Object2
depending on the value of the keyword OBJECT which is specified in table 3-3.
Table 3-3: CDM KVN Metadata
Normative Values/
Keyword Description Examples N/E Obligatory
COMMENT (See 6.3.4 for formatting COMMENT This is a E No
rules.) comment
OBJECT The object to which the OBJECT1 N Yes
metadata and data apply
OBJECT2
(Object1 or Object2).
OBJECT_DESIGNATOR The satellite catalog 12345 E Yes
designator for the object. (See
5.2.9 for formatting rules.)
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CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES
Normative Values/
Keyword Description Examples N/E Obligatory
CATALOG_NAME The satellite catalog used for SATCAT E Yes
the object. (See 5.2.9 for
formatting rules.)
OBJECT_NAME Spacecraft name for the SPOT, ENVISAT, E Yes
object. IRIDIUM, INTELSAT
INTERNATIONAL_DESIGNATOR The full international 2002-021A E Yes
designator for the object.
2002-009A
Values shall have the format
1997-020AA
YYYY-NNNP{PP}, where:
1998-037ABC
YYYY = year of launch;
2001-049PE
NNN = three-digit serial
UNKNOWN
number of launch (with
leading zeros);
P{PP} = At least one capital
letter for the identification of
the part brought into space by
the launch. In cases where the
object has no international
designator, the value
UNKNOWN should be used.
(See 5.2.9 for further
formatting rules.)
PAYLOAD
OBJECT_TYPE The object type. N No
ROCKET BODY
DEBRIS
UNKNOWN
OTHER
OPERATOR_CONTACT_POSITION Contact position of the ORBITAL SAFETY E No
owner/operator of the object. ANALYST (OSA),
NETWORK
CONTROLLER
OPERATOR_ORGANIZATION Contact organization of the EUMETSAT, ESA, E No
object. INTELSAT, IRIDIUM
OPERATOR_PHONE Phone number of the contact [phone] E No
position or organization for the
object.
OPERATOR_EMAIL Email address of the contact JOHN.DOE@ E No
position or organization of the
SOMEWHERE.NET
object.
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CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES
Normative Values/
Keyword Description Examples N/E Obligatory
EPHEMERIS_NAME Unique name of the external EPHEMERIS E Yes
ephemeris file used for the SATELLITE A,
object or NONE. This is used
NONE
to indicate whether an external
(i.e., Owner/Operator [O/O]
provided) ephemeris file was
used to calculate the CA. If
‘NONE’ is specified, then the
output of the most current
Orbit Determination (OD) of
the CDM originator was used
in the CA.
COVARIANCE_METHOD Method used to calculate the CALCULATED N Yes
covariance during the OD that DEFAULT
produced the state vector, or
whether an arbitrary, non-
calculated default value was
used. Caution should be used
when using the default value
for calculating collision
probability.
MANEUVERABLE The maneuver capacity of the YES N Yes
object. (See 1.4.3.1 for
NO
definition of ‘N/A’.)
N/A
ORBIT_CENTER The central body about which EARTH E No
Object1 and Object2 orbit. If
SUN
not specified, the center is
MOON
assumed to be Earth.
MARS
REF_FRAME Name of the reference frame GCRF (see reference N Yes
in which the state vector data [F11])
are given. Value must be
EME2000
selected from the list of values
ITRF
to the right (see reference [F1])

and be the same for both
Object1 and Object2.
GRAVITY_MODEL The gravity model used for the EGM-96: 36D 36O E No
OD of the object. (See annex WGS-84_GEOID: 24D
E under GRAVITY_MODEL for 24O
definition).
JGM-2 : 41D 41O
ATMOSPHERIC_MODEL The atmospheric density JACCHIA 70 E No
model used for the OD of the
MSIS
object. If ‘NONE’ is specified,
JACCHIA 70 DCA
then no atmospheric model
NONE
was used.
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CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES
Normative Values/
Keyword Description Examples N/E Obligatory
N_BODY_PERTURBATIONS The N-body gravitational MOON, SUN E No
perturbations used for the OD
JUPITER
of the object. If ‘NONE’ is
NONE
specified, then no third-body
gravitational perturbations
were used.
SOLAR_RAD_PRESSURE Indication of whether solar YES N No
radiation pressure
NO
perturbations were used for the
OD of the object.
EARTH_TIDES Indication of whether solid YES N No
Earth and ocean tides were
NO
used for the OD of the object.
INTRACK_THRUST Indication of whether in-track YES N No
thrust modeling was used for
NO
the OD of the object.
3.5 CDM DATA
3.5.1 The CDM Data section shall be formed as logical blocks:
– OD Parameters;
– Additional Parameters;
– State Vector; and
– Covariance Matrix.
3.5.2 The logical blocks of the CDM Data section shall consist of KVN elements as
defined in table 3-4, which specifies for each data item:
a) the keyword to be used;
b) a short description of the item;
c) the units to be used if applicable; and
d) whether the item is obligatory or optional.
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CCSDS RECOMMENDED STANDARD FOR CONJUNCTION DATA MESSAGES
Table 3-4: CDM KVN Data
Keyword Description Units Obligatory
COMMENT (See 6.3.4 for formatting rules.) n/a No
OD Parameters
COMMENT (See 6.3.4 for formatting rules.) n/a No
TIME_LASTOB_START The start of a time interval (UTC) that n/a No
contains the time of
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