SIST-TP CEN/TR 17603-50:2022

Space engineering - Communication guidelines

This ECSS handbook is intended to help implementers and users of data handling systems who are adhering to the EN 16603-50 (equivalent to ECSS-E-ST-50) series of standards. The handbook provides an overview of the EN 16603-50 standards and related CCSDS Recommended Standards and describes how the individual standards may be used together to form a coherent set of communications protocols. It also evaluates issues which could not be discussed in the Standards documents themselves, and provides guidance on option selection and implementation choices.
It provides guidance to the EN 16603-50 series of standards including related CCSDS Recommendations. The information provided is informative and intended to be used as best practice; it is not binding on implementers.
The information contained in this handbook is not part of the Standards. In the event of any conflict between the Standards and the material presented in this handbook, the ECSS Standards prevail.

Raumfahrttechnik - Richtlinien zur Kommunikation

Ingénierie spatiale - Recommandations pour les systèmes de communications

Vesoljska tehnika - Smernice za komuniciranje

Namen tega priročnika ECSS je pomagati izvajalcem in uporabnikom sistemov za obdelavo podatkov, ki uporabljajo skupino standardov EN 16603-50 (enakovredno standardu ECSS-E-ST-50). Priročnik vsebuje pregled standardov EN 16603-50 in sorodnih standardov, ki jih priporoča CCSDS, ter opisuje, kako je mogoče posamezne standarde skupaj uporabiti za oblikovanje smiselnega sklopa komunikacijskih protokolov. Poleg tega so v njem ovrednotena vprašanja, ki jih ni bilo mogoče obravnavati v samih dokumentih standardov, ter podane so smernice glede izbire možnosti in možnih izvedb.
Podaja smernice za skupino standardov EN 16603-50, vključno s povezanimi priporočili CCSDS. Navedene informacije so informativne in namenjene uporabi kot najboljša praksa; za izvajalce niso zavezujoče.
Informacije, ki jih vsebuje ta priročnik, niso del standardov. V primeru neskladij med standardi in gradivom, predstavljenim v tem priročniku, imajo prednost standardi ECSS.

General Information

• Status: Published
• Publication Date: 29-Jun-2022
• ICS: 49.140 - Space systems and operations
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 20-Jun-2022
• Due Date: 25-Aug-2022
• Completion Date: 30-Jun-2022
• Ref Project: CEN/TR 17603-50:2022 - Space engineering - Communication guidelines

Overview

CEN/TR 17603-50:2022 - Space engineering: Communication guidelines - is an ECSS-style technical report that aids implementers and users of data handling systems complying with the EN 16603-50 (equivalent to ECSS‑E‑ST‑50) series. This handbook explains how the EN 16603‑50 suite and related CCSDS recommendations can be combined into a coherent communications protocol stack, evaluates topics outside the standards’ normative text, and provides recommended practices, option selection guidance, and implementation advice. The content is informative (best practice) and not binding; where conflicts arise, ECSS standards take precedence.

Key topics

The report comprehensively covers space communications topics including:

• Protocol stack overview: physical, data link, network, transport and application layers as defined in ECSS/EN 16603‑50 and CCSDS.
• Telemetry (TM) and Telecommand (TC): transfer frame protocols, synchronization and channel coding, decoder guidance.
• Space link protocols: AOS (Advanced Orbiting Systems), Proximity‑1, and synchronous/asynchronous link considerations.
• Radio frequency & modulation: RF/modulation considerations and differences versus CCSDS recommendations.
• Data packet services: CCSDS Space Packet, encapsulation, IP (IPv4/IPv6) usage in space contexts.
• Reliable delivery and file transfer: CCSDS CFDP guidance and options.
• Supporting technologies: SpaceWire networks, MIL‑1553 extensions, discrete interfaces, time codes, and spacecraft identifiers.
• Data handling concerns: compression (CCSDS 121/122), playback of recorded data, idle data handling, security, interoperability, and conformance (PICS).
• Architectures and rationale: evolution of standards, DTN/SOIS context, and guidelines for selecting architectures.

Practical applications and users

CEN/TR 17603‑50:2022 is intended for:

• Spacecraft systems engineers designing onboard communications and data handling.
• Ground segment architects planning TM/TC processing, ranging and Doppler tracking.
• Firmware/software developers implementing protocol stacks (AOS, Space Packet, CFDP, Proximity‑1).
• Mission integrators and interoperability teams who must align ECSS and CCSDS options.
• Test, validation, and procurement teams using PICS and recommended practices for conformance and supplier requirements.

Practical value includes helping teams select interoperable options, implement link-layer and packet services consistently, and address operational topics (playback, idle data, security) not fully specified in normative standards.

Related standards

• EN 16603‑50 / ECSS‑E‑ST‑50 series (primary normative suite)
• CCSDS Recommended Standards (Space Packet, AOS, Proximity‑1, CFDP, Compression, Time Codes)
• RFCs for IP (IPv4, IPv6) where applicable

Keywords: CEN/TR 17603‑50:2022, Space engineering, Communication guidelines, EN 16603‑50, ECSS E‑50, CCSDS, telemetry, telecommand, AOS, Proximity‑1, SpaceWire, CFDP, space communications, protocol stack, data handling systems.

Standards Content (Sample)

SLOVENSKI STANDARD
01-september-2022
Vesoljska tehnika - Smernice za komuniciranje
Space engineering - Communication guidelines
Raumfahrttechnik - Richtlinien zur Kommunikation
Ingénierie spatiale - Recommandations pour les systèmes de communications
Ta slovenski standard je istoveten z: CEN/TR 17603-50:2022
ICS:
49.140 Vesoljski sistemi in operacije Space systems and
operations
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL REPORT CEN/TR 17603-50

RAPPORT TECHNIQUE
TECHNISCHER BERICHT
June 2022
ICS 49.140
English version
Space engineering - Communication guidelines
Ingénierie spatiale - Recommandations pour les Raumfahrttechnik - Richtlinien zur Kommunikation
systèmes de communications
This Technical Report was approved by CEN on 20 April 2022. It has been drawn up by the Technical Committee CEN/CLC/JTC 5.

CEN and CENELEC members are the national standards bodies and national electrotechnical committees of Austria, Belgium,
Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia,
Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.

CEN-CENELEC Management Centre:
Rue de la Science 23, B-1040 Brussels
© 2022 CEN/CENELEC All rights of exploitation in any form and by any means
Ref. No. CEN/TR 17603-50:2022 E
reserved worldwide for CEN national Members and for
CENELEC Members.
Table of contents
European Foreword . 15
1 Introduction . 16
1.1 Purpose . 16
1.2 Scope . 16
1.3 Document structure . 16
2 Terms, definitions and abbreviations . 18
2.1 Terms and definitions from other documents . 18
2.2 Terms specific to the present document . 18
2.3 Conventions. 18
2.3.1 Bit numbering and most significant bit . 18
2.4 Abbreviated terms. 19
3 The E-50 series of standards . 23
3.1 Background . 23
3.1.1 Scope of the ECSS E-50 series . 23
3.1.2 CCSDS standards . 23
3.1.3 Relationship to PSS standards . 24
3.1.4 Relationship of ECSS standards to CCSDS standards . 25
3.2 Standards covered in this handbook . 25
3.3 ECSS E-50 Protocols . 28
3.3.1 Physical Layer . 30
3.3.2 Data Link Layer . 30
3.3.3 Network Layer . 31
3.3.4 Transport Layer . 31
3.3.5 Application Layer . 32
3.4 End to End Aspects . 32
4 Standards overview . 35
4.1 Introduction . 35
4.2 E-ST-50: Communications . 35
4.2.1 Purpose and usage . 35
4.2.2 Description . 35
4.2.3 Options . 36
4.2.4 Recommended practice . 36
4.3 E-ST-50-02: Ranging and Doppler tracking . 37
4.3.1 Purpose and usage . 37
4.3.2 Description . 37
4.3.3 Options . 38
4.3.4 Recommended practice . 39
4.4 E-ST-50-05: Radio frequency and modulation . 40
4.4.1 Purpose and usage . 40
4.4.2 Description . 40
4.4.3 Differences from CCSDS 401.0-B . 41
4.4.4 Options . 42
4.4.5 Recommended practice . 42
4.5 E-ST-50-01: Telemetry synchronization and channel coding . 45
4.5.1 Purpose and usage . 45
4.5.2 Description . 45
4.5.3 Differences from CCSDS 131.0-B-1 . 49
4.5.4 Options . 50
4.5.5 Recommended practice . 51
4.6 E-ST-50-03: Telemetry transfer frame protocol . 52
4.6.1 Purpose and usage . 52
4.6.2 Description . 53
4.6.3 Differences from CCSDS 132.0-B-1 . 56
4.6.4 Options . 58
4.6.5 Recommended practice . 58
4.7 E-ST-50-04: Telecommand protocols, synchronization and channel coding . 60
4.7.1 Introduction . 60
4.7.2 Purpose and usage . 60
4.7.3 Description . 61
4.7.4 Differences from CCSDS recommendations . 67
4.7.5 Options . 73
4.7.6 Recommended practice . 73
4.7.7 Telecommand decoder specification . 74
4.8 CCSDS 732.0-B: AOS Space Data Link Protocol . 75
4.8.1 Purpose and usage . 75
4.8.2 Options . 78
4.8.3 Recommended practice . 78
4.9 CCSDS Proximity-1 Space Link Protocol . 80
4.9.1 Purpose and usage . 80
4.9.2 Description . 80
4.9.3 Options . 82
4.9.4 Recommended practice . 82
4.10 CCSDS Packet Protocols . 84
4.10.1 Introduction . 84
4.10.2 CCSDS 133.0-B: Space Packet Protocol . 84
4.10.3 CCSDS 133.1-B: Encapsulation Service . 87
4.11 Internet Protocols. 88
4.11.1 Introduction . 88
4.11.2 RFC 791: Internet Protocol Version 4 . 88
4.11.3 RFC 1883: Internet Protocol Version 6 . 89
4.12 E-ST-70-41: Telemetry and telecommand packet utilization . 91
4.12.1 Purpose and usage . 91
4.12.2 Description . 91
4.12.3 Options . 92
4.12.4 Recommended practice . 92
4.13 CCSDS 727.0-B: CCSDS File Delivery Protocol (CFDP) . 93
4.13.1 Purpose and usage . 93
4.13.2 Description . 94
4.13.3 Options . 97
4.13.4 Recommended practice . 97
4.14 CCSDS 135.0-B: Space Link Identifiers . 99
4.14.1 Purpose and usage . 99
4.14.2 Description . 99
4.14.3 Options . 102
4.14.4 Recommended practice . 102
4.15 CCSDS 320.0-B: CCSDS Global Spacecraft Identification Field . 103
4.15.1 Purpose and usage . 103
4.15.2 Description . 103
4.15.3 Options . 103
4.15.4 Recommended practice . 104
4.16 Data Compression . 105
4.16.1 Purpose and usage . 105
4.16.2 CCSDS 121.0-B: Lossless Data Compression . 106
4.16.3 CCSDS 122.0-B: Image Data Compression . 107
4.17 CCSDS 301.0-B: Time Code Formats . 112
4.17.1 Purpose and usage . 112
4.17.2 Description . 112
4.17.3 Options . 112
4.17.4 Recommended practice . 112
4.18 E-ST-50-12: SpaceWire. Links, nodes, routers and networks . 113
4.18.1 Purpose and usage . 113
4.18.2 Description . 113
4.18.3 Options . 114
4.18.4 Recommended practice . 114
4.19 E-ST-50-13: MIL 1553 Standard extension . 115
4.19.1 Purpose and usage . 115
4.19.2 Description . 115
4.19.3 Recommended practice . 115
4.20 E-ST-50-14: Spacecraft discrete interfaces. 116
4.20.1 Purpose and usage . 116
4.20.2 Description . 116
4.20.3 Options . 117
4.20.4 Recommended practice . 118
5 Specific topics . 119
5.1 Introduction . 119
5.2 Synchronization and channel coding . 119
5.2.1 Functions of synchronization and channel coding . 119
5.2.2 Coding options . 120
5.3 Playback of recorded data . 123
5.3.1 Legacy systems with stored TM Transfer Frames . 123
5.3.2 Systems with stored AOS Transfer Frames. 123
5.3.3 Current systems . 124
5.4 Idle data . 124
5.4.1 Synchronous channel: TM and AOS . 124
5.4.2 Asynchronous channel: TC and Proximity-1 . 127
5.5 Compression . 127
5.6 Security . 128
5.7 Interoperability . 129
5.8 Conformance and PICS . 130
6 Rationale and architectures . 132
6.1 Evolution of space communications standards . 132
6.1.1 The beginning of CCSDS . 132
6.1.2 Standards for TC and TM . 133
6.1.3 Later standards: AOS, Proximity-1 and CFDP . 133
6.1.4 New developments: DTN and SOIS . 133
6.1.5 CCSDS and ECSS standards . 135
6.2 Guidelines . 135
7 Supporting components . 137
7.1 Introduction . 137
7.2 Flight components . 137
7.3 Ground components . 137
7.4 Industry . 137
Annex A (informative) Draft PICS for ECSS-E-ST-50-01: Sending end . 138
A.1 Introduction to the PICS . 138
A.1.1 Purpose . 138
A.1.2 Format of the PICS . 138
A.2 Identification . 141
A.3 Channel coding . 142
A.4 Convolutional code . 143
A.5 Reed-Solomon code . 144
A.6 Concatenation of Reed-Solomon code and convolutional code . 145
A.7 Reed-Solomon code and 4D-8PSK-TCM . 147
A.8 Turbo code . 148
A.9 Uncoded . 149
A.10 External items . 150
Annex B (informative) Draft PICS for ECSS-E-ST-50-01: Receiving end . 151
B.1 Introduction to the PICS . 151
B.1.1 Purpose . 151
B.1.2 Format of the PICS . 151
B.2 Identification . 154
B.3 Channel coding . 155
B.4 Convolutional code . 156
B.5 Reed-Solomon code . 158
B.6 Concatenation of Reed-Solomon code and convolutional code . 159
B.7 Reed-Solomon code and 4D-8PSK-TCM . 161
B.8 Turbo code . 162
B.9 Uncoded . 163
B.10 External items . 164
Annex C (informative) Draft PICS for ECSS-E-ST-50-03: Sending end . 165
C.1 Introduction to the PICS . 165
C.1.1 Purpose . 165
C.1.2 Format of the PICS . 165
C.2 Identification . 168
C.3 TM Transfer Frame format . 169
C.3.1 General . 169
C.3.2 Transfer Frame Primary Header . 169
C.3.3 Transfer Frame Secondary Header . 172
C.3.4 Transfer Frame Data Field . 174
C.3.5 Operational Control Field . 176
C.3.6 Frame Error Control Field . 178
C.4 TM Transfer Frame length . 179
C.5 Packet processing function . 179
C.6 External items . 181
Annex D (informative) Draft PICS for ECSS-E-ST-50-03: Receiving end . 183
D.1 Introduction to the PICS . 183
D.1.1 Purpose . 183
D.1.2 Format of the PICS . 183
D.2 Identification . 186
D.3 TM Transfer Frame format . 187
D.3.1 General . 187
D.3.2 Transfer Frame Primary Header . 187
D.3.3 Transfer Frame Secondary Header . 189
D.3.4 Transfer Frame Data Field . 191
D.3.5 Operational Control Field . 193
D.3.6 Frame Error Control Field . 194
D.4 TM Transfer Frame length . 194
D.5 Packet extraction function . 195
Annex E (informative) Draft PICS for ECSS-E-ST-50-04: Sending end . 196
E.1 Introduction to the PICS . 196
E.1.1 Purpose . 196
E.1.2 Format of the PICS . 196
E.2 Identification . 199
E.3 Supported layers and sublayers. 200
E.4 Segmentation sublayer . 201
E.4.1 Introduction . 201
E.4.2 Elements of the segmentation sublayer . 202
E.4.3 TC Segments . 203
E.4.4 Segmentation . 204
E.4.5 Blocking function on a virtual channel that carries TC Segments . 205
E.4.6 Blocking function on a virtual channel that does not carry TC
Segments . 207
E.4.7 MAP multiplexing . 208
E.4.8 Transfer notification . 208
E.5 Transfer sublayer . 209
E.5.1 Introduction . 209
E.5.2 Elements of the transfer sublayer . 209
E.5.3 TC Transfer Frame data structure . 210
E.5.4 CLCW data structure . 211
E.5.5 Sending end of COP-1 protocol, FOP-1 . 212
E.5.6 Procedures below FOP-1 . 213
E.5.7 Virtual channel multiplexing . 214
E.6 Synchronization and channel coding sublayer . 215
E.6.1 Introduction . 215
E.6.2 Elements of the synchronization and channel coding sublayer . 215
E.6.3 CLTU and BCH codeblock . 216
E.6.4 Pseudo-randomization procedure . 218
E.6.5 BCH encoding procedure . 218
E.6.6 Handling of Abort request from FOP-1 . 219
E.7 Physical layer . 220
E.7.1 Introduction . 220
E.7.2 Elements of the physical layer . 221
E.7.3 Data structures . 222
E.7.4 Carrier Modulation Modes . 223
E.7.5 PLOP-2 . 224
E.7.6 PLOP-1 . 224
E.7.7 Handling of Abort request from FOP-1 . 225
Annex F (informative) Draft PICS for ECSS-E-ST-50-04: Receiving end . 226
F.1 Introduction to the PICS . 226
F.1.1 Purpose . 226
F.1.2 Format of the PICS . 226
F.2 Identification . 229
F.3 Supported layers and sublayers. 230
F.4 Segmentation sublayer . 231
F.4.1 Introduction . 231
F.4.2 Elements of the segmentation sublayer . 232
F.4.3 TC Segments . 233
F.4.4 MAP demultiplexing . 234
F.4.5 Reassembly function . 235
F.4.6 Deblocking function on a virtual channel that carries TC Segments . 237
F.4.7 Deblocking function on a virtual channel that does not carry TC
Segments . 238
F.5 Transfer sublayer . 239
F.5.1 Introduction . 239
F.5.2 Elements of the transfer sublayer . 239
F.5.3 TC Transfer Frame data structure . 240
F.5.4 CLCW data structure . 241
F.5.5 Procedures to process a candidate frame . 241
F.5.6 Virtual channel demultiplexing . 242
F.5.7 FARM-1 (receiving end of COP-1 protocol) . 243
F.6 Synchronization and channel coding sublayer . 244
F.6.1 Introduction . 244
F.6.2 Elements of synchronization and channel coding sublayer. 244
F.6.3 CLTU and BCH codeblock . 245
F.6.4 Receiving-end channel logic . 246
F.6.5 BCH decoding procedure . 246
F.6.6 Pseudo-derandomization procedure . 247
F.7 Physical layer . 248
Annex G (informative) False decoding probabilities for concatenated R-S
E=8 with 4D-8PSK-TCM . 249
G.1 Introduction . 249
G.2 False decoding probabilities . 249
References . 253

Figures
Figure 2-1: Bit numbering convention . 19
Figure 3-1: ECSS E-50 standards and associated layers . 29
Figure 3-2: Some options for combining the protocols . 30
Figure 3-3: Simplified end-to-end communication system . 33
Figure 3-4: End-to-end system with example protocol stacks . 33
Figure 3-5: Store and forward system with example protocol stacks. 34
Figure 4-1: Ranging and Doppler tracking - Functional block diagram . 38
Figure 4-2: Cryosat-2 S-band TT&C subsystem . 44
Figure 4-3: Format of channel access data unit (CADU) . 46
Figure 4-4: Coding, randomization and synchronization configurations (1) . 47
Figure 4-5: Coding, randomization and synchronization configurations (2) . 48
Figure 4-6: TM Transfer Frame . 53
Figure 4-7: TM Transfer Frame Primary Header . 56
Figure 4-8: Layers and sublayers in ECSS-E-ST-50-04 . 61
Figure 4-9: Telecommand layers, sublayers and data units . 61
Figure 4-10: TC Transfer Frame . 65
Figure 4-11: AOS Transfer Frame . 76
Figure 4-12: AOS Transfer Frame Primary Header . 76
Figure 4-13: Relationships between channels of the Space Data Link Protocols . 100
Figure 4-14: Functional parts of the compressor. 108
Figure 4-15: Architectural context of interfaces defined in ECSS-E-ST-50-14 . 117
Figure 6-1: SOIS overall architecture . 134

Figure G-1 : WER (byte) Performance Comparison . 251
Figure G-2 : For 4D-8PSK-TCM 2 b/s/Hz + RS(254,238), I=8 . 251
Figure G-3 : For 4D-8PSK-TCM 2.5 b/s/Hz + RS(254,238), I=8 . 252

Tables
Table 3-1: ECSS E-ST-50 standards covered in this handbook . 26
Table 3-2: Other standards covered in this handbook . 27
Table 3-3: Standards for the TM, TC and AOS Space Data Link Protocols . 27
Table 4-1: Options for Ranging and Doppler tracking . 39
Table 4-2: Interpretation of Bypass Flag and Control Command Flag . 65
Table 4-3: Name correspondence between CCSDS and ECSS-E-ST-50-04 . 71
Table 4-4: Some differences between AOS and TM transfer frames . 77
Table 4-5: CFDP best practice for options and parameters . 83
Table 4-6: Some of the identifiers covered by CCSDS 135.0-B . 99
Table 4-7: Space link addressing . 101
Table 4-8: Space network addressing . 102
Table 5-1 Functions of synchronization and channel coding standards . 120
Table 5-2: Coding gains and bandwidth expansions . 121
Table 5-3: Idle data in a TM Transfer Frame . 125
Table 5-4 Idle data in an AOS Transfer Frame . 125
Table 5-5: Draft PICS proforma included in the annexes . 131
Table 6-1: Applicability of standards for space link . 135
Table 6-2: Applicability of standards for Network / Transport / Application layers . 136
Table 6-3: Applicability of standards for management . 136
Table 6-4: Applicability of standards for onboard . 136

Table A-1 : Symbols for item status . 139
Table A-2 : Labelled boxes for support . 139
Table A-3 : PICS identification . 141
Table A-4 : Supported channel codes . 142
Table A-5 : Items for convolutional code . 143
Table A-6 : Items for Reed-Solomon code . 144
Table A-7 : Items for concatenated R-S and convolutional code . 146
Table A-8 : Items for Reed-Solomon code and 4D-8PSK-TCM . 147
Table A-9 : Items for turbo code . 148
Table A-10 : Items when no channel coding is used . 149
Table A-11 : External items . 150
Table B-1 : Symbols for item status . 152
Table B-2 : Labelled boxes for support . 152
Table B-3 : PICS identification . 154
Table B-4 : Supported channel codes . 155
Table B-5 : Items for convolutional code . 157
Table B-6 : Items for Reed-Solomon code . 158
Table B-7 : Items for concatenated R-S and convolutional code . 159
Table B-8 : Items for Reed-Solomon code and 4D-8PSK-TCM . 161
Table B-9 : Items for turbo code . 162
Table B-10 : Items when no channel coding is used . 163
Table B-11 : External items . 164
Table C-1 : Symbols for item status . 166
Table C-2 : Labelled boxes for support . 166
Table C-3 : PICS identification . 168
Table C-4 : Major fields in TM Transfer Frame . 169
Table C-5 : Items for Transfer Frame Primary Header . 169
Table C-6 : Items for Transfer Frame Primary Header when Synchronization Flag = ‘0’ . 171
Table C-7 : Items for frames with Transfer Frame Secondary Header . 173
Table C-8 : Items for frames with extended virtual channel frame count . 174
Table C-9 : Items for Transfer Frame Data Field . 174
Table C-10 : Items for frames with asynchronously inserted data as specified in clause
5.4.4 . 175
Table C-11 : Items for frames with Operational Control Field . 177
Table C-12 : Items for frames with Frame Error Control Field . 178
Table C-13 : Items for the length of the TM Transfer Frame . 179
Table C-14 : Items for packet processing function . 180
Table C-15 : External items . 181
Table D-1 : Symbols for item status . 184
Table D-2 : Labelled boxes for support . 184
Table D-3 : PICS identification . 186
Table D-4 : Major fields in TM
...