ECSS-E-50 Part 2A

4 July 2005

EUROPEAN COOPERATION

ECSS
FOR SPACE STANDARDIZATION

Space engineering

Communications – Part 2:
Document requirements definitions
(DRDs)

ECSS Secretariat
ESA-ESTEC
Requirements & Standards Division
Noordwijk, The Netherlands
ECSS--E--50 Part 2A
4 July 2005 ECSS

Published by: ESA Publications Division

ESTEC, P.O. Box 299,
2200 AG Noordwijk,
The Netherlands
ISSN: 1028-396X
Price: € 10
Printed in: The Netherlands
Copyright: E2005 by the European Space Agency for the members of ECSS

2
ECSS
ECSS--E--50 Part 2A
4 July 2005

Foreword

This Standard is one of the series of ECSS Standards intended to be applied

together for the management, engineering and product assurance in space
projects and applications. ECSS is a cooperative effort of the European Space
Agency, national space agencies and European industry associations for the
purpose of developing and maintaining common standards.
Requirements in this Standard are defined in terms of what must be accom-
plished, rather than in terms of how to organize and perform the necessary work.
This allows existing organizational structures and methods to be applied where
they are effective, and for the structures and methods to evolve as necessary
without rewriting the standards.
The formulation of this Standard takes into account the existing ISO 9000 family
of documents.
This Standard is divided in two parts:
D Part 1 defines the principles and requirements applicable to communications
engineering.
D Part 2 defines the content of the DRDs which are specifically referenced
in Part 1.
This Standard has been prepared by the ECSS--E--50 Working Group, reviewed by
the ECSS Engineering Panel and approved by the ECSS Steering Board.

3
ECSS--E--50 Part 2A
4 July 2005 ECSS

(This page is intentionally left blank)

4
 ECSS
ECSS--E--50 Part 2A
4 July 2005

Contents

Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2 Normative references . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3 Terms, definitions and abbreviated terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.1 Terms and definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.2 Abbreviated terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

4 Document requirements definitions (DRD) list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Annex A (normative) Communication system requirements document (CSRD) DRD . . 17

Annex B (normative) Communication system baseline definition (CSBD) DRD . . . . . . . 21

Annex C (normative) Communication system analysis document (CSAD) DRD . . . . . . 25

Annex D (normative) Communication system verification plan (CSVP) DRD . . . . . . . . . 27

Annex E (normative)
Communication system architectural design document (CSADD) DRD . . . . . . . . . . . . . 29

Annex F (normative)
Communication system detailed design document (CSDDD) DRD . . . . . . . . . . . . . . . . . 31

Annex G (normative) Communication system profile document (CSPD) DRD . . . . . . . . 33

5
 ECSS--E--50 Part 2A
4 July 2005 ECSS
Annex H (normative) Communication system operations manual (CSOM) DRD . . . . . . 35

Tables

Table 1: ECSS-E-50 DRD list .................................................... 14

6
ECSS
ECSS--E--50 Part 2A
4 July 2005

Scope

This Part 2 of ECSS--E--50 defines the content of the document requirements

definitions (DRDs) that are called up by other ECSS Standards and explicitly
referenced in ECSS--E--50 Part 1.

7
ECSS--E--50 Part 2A
4 July 2005 ECSS

(This page is intentionally left blank)

8
ECSS
ECSS--E--50 Part 2A
4 July 2005

Normative references

The following normative documents contain provisions which, through reference

in this text, constitute provisions of this ECSS Standard. For dated references,
subsequent amendments to, or revisions of any of these publications do not apply.
However, parties to agreements based on this ECSS Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative
documents indicated below. For undated references the latest edition of the
publication referred to applies.
ECSS--P--001 Glossary of terms
ECSS--E--50 Part 1A Space engineering -- Communications -- Part 1: Principles
and requirements
ECSS--M--50 Space project management -- Information/documentation
management

9
ECSS--E--50 Part 2A
4 July 2005 ECSS

(This page is intentionally left blank)

10
ECSS
ECSS--E--50 Part 2A
4 July 2005

Terms, definitions and abbreviated terms

3.1 Terms and definitions

For the purposes of this document, the terms and definitions given in
ECSS--P--001 and ECSS--E--50 Part 1 apply.

3.2 Abbreviated terms

The following abbreviated terms are defined and used within this document:
Abbreviations Meaning
CSAD communication system analysis document
CSADD communication system architectural design document
CSBD communication system baseline definition
CSDDD communication system detailed design document
CSOM communication system operations manual
CSPD communication system profile document
CSRD communication system requirements document
CSVP communication system verification plan
DRD document requirements definition
LEOP launch and early operations phase
RF radio frequency

11
ECSS--E--50 Part 2A
4 July 2005 ECSS

(This page is intentionally left blank)

12
ECSS
ECSS--E--50 Part 2A
4 July 2005

Document requirements definitions (DRD) list

ECSS Standards specify the production and use of project documents. Document
requirements definitions are defined to control the content of the project
documents.
Document requirements definitions serve to ensure:
a. completeness and consistency of information within documents,
b. that the information contained in a document conforms to its defined scope,
and correctly implements its interfaces with other documents, and
c. that portions of a document can be generated or maintained by separate
organizational groups and seamlessly integrated into a coherent whole.
Table 1 lists and summarizes the DRDs that are defined in the annexes of this
Standard and called up in ECSS--E--50 Part 1.

13
14
Table 1: ECSS--E--50 DRD list
Applicable
DRD ID DRD Title DRD summary content Delivered Remarks
to (phase)
ECSS--E--50 Communication system Formally describes the requirements from the Requirement SRR
4 July 2005

Part 2A requirements document customer on the spacecraft communication engineering

Annex A (CSRD) system. Covers ground network, spacelink, and
on-board network requirements, design,
development, and operation.
ECSS--E--50 Part 2A

ECSS--E--50 Communication system Formal response to the CSRD that constitutes Analysis PDR
Part 2A baseline definition (CSBD) the technical baseline for the design and
Annex B implementation of the spacecraft communication
system. Includes a compliance matrix with the
CSRD and any derived requirements. Documents
any major assumptions and constraints and
non-compliances.
ECSS--E--50 Communication system Contains a full technical analysis of the Analysis PDR
Part 2A analysis document (CSAD) communication system leading to the selection
Annex C of frequencies, protocols, protocol options,
redundancy strategy, and operational concept.
ECSS--E--50 Communication system Describes the verification test plan for the Analysis, PDR
Part 2A verification plan (CSVP) spacecraft communication system. Plan covers verification
Annex D tests carried out during verification phase and
tests that may be used during operations.
ECSS--E--50 Communication system Describes the architectural design of the Design and PDR
Part 2A architectural design document spacecraft communication system and shows the configuration
Annex E (CSADD) relationships between the communication system
and other mission systems.
ECSS--E--50 Communication system Describes the detailed design of the spacecraft Design and CDR
Part 2A detailed design document communication system. configuration
Annex F (CSDDD)
ECSS
 Table 1: ECSS--E--50 DRD list (continued)
Applicable
DRD ID DRD Title DRD summary content Delivered Remarks
to (phase)
ECSS

ECSS--E--50 Communication system profile Documents the communication system profile, Design and CDR 1. The CSPD constitutes the
Part 2A document (CSPD) including frequency assignments, protocol configuration formal statement of
Annex G selection, protocol options, address assignments, compliance to ECSS--E--50.
channel assignments, spacecraft identifier 2. ECSS Level 3 standards
assignments, spacelink bandwidth allocations, applied to the communication
and onboard bus bandwidth allocations for TM system have their own profile
and TC. documents.
ECSS--E--50 Communication system Formally describes all procedures for the Analysis PDR
Part 2A operations manual (CSOM) operation of the spacecraft communication
Annex H system. Covers normal and contingency
operations. Normal operations include procedures
such as spacecraft signal acquisition, loss of
signal, and hand--over, as well as communication
system management activities such as address
initialization and router configuration and
maintenance. Contingency operations cover
uni--directional communications (uplink only,
downlink only) and unexpected loss and
discontinuous signal.
ECSS--E--50 Part 2A
4 July 2005

15
ECSS--E--50 Part 2A
4 July 2005 ECSS

(This page is intentionally left blank)

16
ECSS
ECSS--E--50 Part 2A
4 July 2005

Annex A (normative)

Communication system requirements document

(CSRD) DRD

A.1 DRD identification

A.1.1 Requirement identification and source document
ECSS--E--50 Part 1A, requirement 5.2.1.3.

A.1.2 Purpose and objective

The communication system requirements document (CSRD) contains the top level
assumptions, constraints and communication system requirements for a given
mission to enable the supplier of the communication system to elaborate a design
for the communication system.
The CSRD is written by the space project customer and is the highest level
requirements document defining the requirements on the space communication
system. The supplier of the space communication system formally responds to the
CSRD with the communication system baseline definition (CSBD, see Annex B)
where all the requirements in the CSRD can be traced to a proposed implementa-
tion.

A.2 Expected response

A.2.1 Response identification
The requirements for document identification contained in ECSS--M--50 shall be
applied to the CSRD.

A.2.2 Scope and contents

The CSRD shall provide the information presented in the following sections:

17
ECSS--E--50 Part 2A
4 July 2005 ECSS
<1> Introduction
The CSRD shall contain a description of the purpose, objective, content
and the reason prompting its preparation.

<2> Applicable and reference documents

The CSRD shall list the applicable and reference documents in support to
the generation of the document.

<3> Mission overview

The CSRD shall briefly describe:
(a) the main objectives and characteristics of the space mission;
(b) the spacecraft;
(c) the instruments on-board the spacecraft;
(d) the ground segment for the control and operations of the spacecraft,
the instruments, and the ground segment itself;
(e) the operations to achieve the goal of the space project.

<4> Project responsibilities

The CSRD shall briefly describe the distribution of responsibilities within
the space project, including the responsibilities of the space project
customer and those of the communication system supplier.

<5> Major project milestones

The CSRD shall summarize:
(a) the major project milestones relating to the space segment;
(b) the major project milestones relating to the ground segment;
(c) major project milestones relating to the communication system.

<6> Mission constraints

The CSRD shall describe:
(a) Launch
(1) The launch vehicle, the launch site location and the ascent
trajectory.
(2) For orbital vehicles, the orbit injection characteristics.
(b) Trajectory
(1) The trajectory of the spacecraft.
(2) Any significant constraints or parameters associated with each
part of the trajectory.
(3) Any notable periods arising from the trajectory during which
communications with the spacecraft are difficult or impossible.
(4) For orbital vehicles, the intended orbital period and visibility
periods and characteristics during which communication can be
performed.
(c) Operational phases
(1) Each distinct operational phase of the space mission.
(2) Any constraints on, and expected characteristics of the com-
munication system for each phase.
NOTE Mission phases usually include LEOP, commis-
sioning, routine operations, and disposal. Other
phases that can be included are contingency
operations, critical manoeuvres, and hibernation.

18
ECSS
ECSS--E--50 Part 2A
4 July 2005

(d) Spacecraft
Any constraints imposed on the communication system by the
spacecraft, such as for example power limitations, antenna pointing
constraints, and prohibited frequencies.
(e) Additional constraints
Any other constraints not covered in the preceding categories, and
other essential mission information that impacts on the design of the
communication system.

<7> Communication system requirements

(a) General
(1) The CSRD shall list the high level requirements on the space
communication system, at a level appropriate to enable all
significant aspects of the communication system technical
baseline to be elaborated.
NOTE This in turn enables:
D informed decision making concerning the devel-
opment and procurement of the communication
system components, and
D the communication system design drivers to be
established.
(2) The list specified in (1) above shall include the communication
system requirements that address the following major system
elements:
-- functional;
-- performance;
-- reliability;
-- availability;
-- interface;
-- design (implementation);
-- maintainability;
-- security.
(3) Where the requirements for a particular system element differ
for different operational or mission phases, the requirements
shall first be listed for the normal operational phases and then
those that are different for other mission phases.
(b) Organization of the communication system requirements
The CSRD shall list:
(1) The overall system requirements on the communication system
including requirements related to:
-- overall system availability and reliability,
-- end-to-end performance,
-- communication system lifetime,
-- design and implementation,
-- interfaces to existing external entities, and
-- compatibility with specific communications protocols.
(2) The security requirements for the communication system.
NOTE As specified in ECSS--E--50 Part 1, this is based on
a threat analysis of the mission.

19
ECSS--E--50 Part 2A
4 July 2005 ECSS
(3) The communication system requirements for the space network,
which comprises all of the nodes of the flight segment of the
mission.
(4) For missions that involve multiple space segment elements,
such as cluster missions, orbiter-lander combinations, lander-
rover combinations, and missions with deployable probes, the
requirements on the communications between those elements.
(5) The requirements for the link between the ground station and
the spacecraft including requirements regarding:
-- uplink and downlink performance,
-- RF frequencies,
-- contact periods and outages,
-- link acquisition, and
-- link failure modes.
(6) The communication system requirements for the ground net-
work, which comprises all of the ground communication
facilities used in the mission, including requirements for
redundancy, availability, and accessibility.

20
ECSS
ECSS--E--50 Part 2A
4 July 2005

Annex B (normative)

Communication system baseline definition

(CSBD) DRD

B.1 DRD identification

B.1.1 Requirement identification and source document
ECSS--E--50 Part 1A, requirement 5.2.3.3.

B.1.2 Purpose and objective

The communication system baseline definition (CSBD) is the top level design
document produced by the communication system supplier to define the
communication system to be developed for the mission. The CSBD forms the basis
for all other specification and design activities undertaken by the communication
system supplier, as well as constituting the baseline for generating cost and
schedule information.
The CSBD constitutes the formal response to the CSRD (see Annex A). All
requirements in the CSRD are traced in the CSBD and appropriately apportioned
into specific CSBD clauses. Furthermore, any additional requirements can be
derived in the CSBD to ensure common understanding and unambiguous
interpretation of the CSRD requirements.

B.2 Expected response

B.2.1 Response identification
The requirements for document identification contained in ECSS--M--50 shall be
applied to the CSBD.

B.2.2 Scope and contents

The CSBD shall provide the information presented in the following sections:

21
ECSS--E--50 Part 2A
4 July 2005 ECSS
<1> Introduction
The CSBD shall contain a description of the purpose, objective, content
and the reason prompting its preparation.

<2> Applicable and reference documents

The CSBD shall list the applicable and reference documents in support to
the generation of the document.

<3> Mission description and communication system overview

The CSBD shall briefly describe:
(a) the main objectives and characteristics of the space mission;
(b) the communication system, including:
(1) the intended communication system implementation,
(2) the main concepts of the proposed communication system,
(3) the system components of the communication system, indicating
where they are located and how they interrelate, and
(4) the proposed protocols and communication frequencies to be
used within the intended communication system.

<4> Mission constraints and implementation assumptions

The CSBD shall describe:
(a) All mission constraints that affect the communication system.
NOTE These can include trajectory induced constraints such
as out of contact, or hibernation mode, attitude induced
constraints such as tumbling mode or antenna pointing
limitations, and ground induced constraints such as
ground station availability.
(b) All of the assumptions made in establishing the communication
system baseline definition.

<5> Communication system interfaces

The CSBD shall summarize:
(a) interfaces between the space network elements of the communication
system and other entities onboard the spacecraft including:
(1) the control interfaces for the onboard elements of the communi-
cation system, indicating how the onboard data handling system
manages space link communication;
(2) the data interfaces that enable onboard entities to send data to
and receive data from the ground;
(b) for missions that have multiple space segment elements:
(1) how the communication links between those elements are
controlled, and
(2) how data is transferred across them;
(c) the interfaces between the ground network elements of the communi-
cation system and other ground entities, including:
(1) the control interfaces for the ground elements of the communica-
tion system, indicating how the ground system manages space
link communication;
(2) the data interfaces that enable ground entities to send data to
and receive data from the spacecraft.

22
ECSS
ECSS--E--50 Part 2A
4 July 2005

<6> Communication system analysis

(a) The CSBD shall describe:
(1) all of the communication system analysis and system studies to
design a communication system that meets the objectives of the
space mission, and
(2) the justification of the analysis and studies referred to in (1)
above.
(b) The CSBD should:
(1) list all communication system issues to be resolved by modelling
or simulation, and
(2) describe the modelling or simulation technique to be applied.
(c) The CSBD shall list the expected performances that can be achieved
by the proposed communication system and indicate whether these
fully meet the mission needs.

<7> Communication system design and implementation

The CSBD shall describe the technical approach to the design and
implementation of the overall communication system and each of its
components.

<8> Communication system integration and technical verification and

validation
The CSBD shall describe the technical approach to the integration and
testing of the communication system elements, and the technical
verification and validation of the communication system as a whole.

<9> Communication system operations

The CSBD shall describe:
(a) All of the operational procedures relating to the communication
system for normal operations.
(b) All of the operational procedures relating to the maintenance of the
communication system.
(c) Special operational procedures to be used for contingency operation
of the communication system, i.e. in case of degradation of its normal
performance.
NOTE These operational procedures can include unidirec-
tional operation of the communication system, e.g.
command-in-the-blind and telemetry-in-the-blind, and
operation at reduced signalling rates.
(d) The technical approach to monitoring the health and performance of
the communication system.
(e) Any communication system specific operations not covered in items
(a) to (d) above.
NOTE For example, these can include procedures to support
in-flight communications experiments, reconfiguration
of the communication system to support new mission
parameters such as the addition of new flight elements,
and procedures to adapt the communication system for
use on other missions.

23
ECSS--E--50 Part 2A
4 July 2005 ECSS
<10> Special project facilities
The CSBD shall describe any special project facilities for the development
and implementation of the communication system (e.g. the modification
of existing ground facilities, or the adaptation of reused flight software).

<11> Support to other disciplines

The CSBD shall describe the support to be provided to other spacecraft
disciplines by the communication system supplier.
NOTE This can include the provision of simulation models of
communication system components, and test harnesses.

<12> Required input and output items and services

The CSBD shall list:
(a) all of the deliverable items and services to be provided by the
communication system supplier to support the mission;
(b) all of the items and services to be provided by the communication
system customer in order to support the development of the
communication system.
NOTE These can include:
D space segment design documents and information;
D ground segment design documents and information;
D access to testbeds, prototypes, and engineering models for
integration and testing;
D simulation models of the ground and space segments.

<13> CSRD vs. CSBD traceability matrix

The CSBD shall provide a CSRD versus CSBD traceability matrix,
summarized in a table, providing the following information for each entry:
— requirements -- containing a list of all requirements in the CSRD;
— reference -- providing a cross reference indicating one or more CSBD
paragraphs where the requirement is fulfilled;
— compliance -- indicating the level of the suppliers’ compliance of the
CSBD to the CSRD with one of the following values:
* COMPLIANT,
* PARTIALLY COMPLIANT, or
* NON-COMPLIANT;
— notes -- briefly describing the justification in those cases where
column three indicates partial or non-compliance.

<14> To-be-resolved items

The CSBD shall list all of the items for which a clear resolution has not yet been
found.

<15> To-be-determined and to-be-confirmed items

The CSBD shall list all of the items for which a specific communication system
implementation cannot be committed without further information.

24
ECSS
ECSS--E--50 Part 2A
4 July 2005

Annex C (normative)

Communication system analysis document

(CSAD) DRD

C.1 DRD identification

C.1.1 Requirement identification and source document
ECSS--E--50 Part 1A, requirement 5.2.2.3.

C.1.2 Purpose and objective

The communication system analysis document (CSAD) is produced by the
communication system supplier to capture the results of analysis and testing of
the communication system. The first issue of the CSAD is produced for the PDR,
but it is updated throughout the project as further communication system analysis
and testing is carried out and, as specified in ECSS--E--50 Part 1, is reviewed at
each major project milestone following the PDR.
The results of all analysis and testing carried out on the communication system
are reported in the CSAD. This document is therefore critical for tracking the
development of the communication system throughout the project, ensuring that
the communication system continues to meet the functional and performance
requirements as the design and implementation are elaborated. The CSAD is used
as a reference for the identification and resolution of any design issues throughout
the development of the communication system.

C.2 Expected response

C.2.1 Response identification
The requirements for document identification contained in ECSS--M--50 shall be
applied to the CSAD.

C.2.2 Scope and contents

The CSAD shall provide the information presented in the following sections:

25
ECSS--E--50 Part 2A
4 July 2005 ECSS
<1> Introduction
The CSAD shall contain a description of the purpose, objective, content
and the reason prompting its preparation.

<2> Applicable and reference documents

The CSAD shall list the applicable and reference documents in support to
the generation of the document.

<3> Mission description and communication system overview

The CSAD shall briefly describe:
(a) the main objectives and characteristics of the space mission, and
(b) the intended communication system implementation.

<4> Overview of analysis approach

The CSAD:
(a) shall provide an overview of the analysis approach applied to the
communication system;
(b) shall describe the goals and objectives of the analyses;
(c) shall describe the different analysis techniques used on the com-
munication system;
(d) should contain a list of the communication system issues to be
resolved by analysis.

<5> Description and results of analysis

(a) The CSAD shall describe each of the analysis techniques applied to
the communication system together with the results of that analysis.
(b) For each technique referred to in (a) above, the CSAD shall include
at least the following:
(1) the objective of the analysis,
(2) a detailed description of the analysis technique,
(3) a description of any tools used to carry out the analysis,
(4) a list of any assumptions made concerning the communication
system or its environment during the analysis,
(5) a list of starting conditions for the analysis,
(6) copies of all inputs to the analysis,
(7) the results of the analysis,
(8) an appraisal of the analysis drawing conclusions and inferences
with respect to the communication system, and
(9) recommendations for the communication system based on the
analysis.
NOTE The objective is that the analysis results can be
reviewed offline, and the analyses can be repeated.
(c) The conclusions referred to in (b) (8) above should indicate whether
the communication system meets its functional and performance
requirements.
(d) The recommendations referred to in (b) (9) above should include
recommendations on design changes.

26
ECSS
ECSS--E--50 Part 2A
4 July 2005

Annex D (normative)

Communication system verification plan (CSVP)

DRD

D.1 DRD identification

D.1.1 Requirement identification and source document
ECSS--E--50 Part 1A, requirements 5.2.2.3, 5.2.3.3 and 5.2.4.3.

D.1.2 Purpose and objective

The communication system verification plan (CSVP) is produced by the
communication system supplier to describe the verification strategy and specific
verification tests used to ensure that the communication system complies with the
requirements established in the CSRD and CSBD. The first issue of the CSVP is
produced for the PDR but, as specified in ECSS--E--50 Part 1, is updated
throughout the project as more detailed tests are defined and critical issues are
identified, and is reviewed at each major project milestone following the PDR.
The communication system verification plan defines the tests to be conducted on
the communication system to verify conformity to CSRD (see Annex A) and CSBD
(see Annex B) requirements and therefore derives from these two documents. The
results of the verification tests and any analysis to be conducted as a part of the
verification process are reported in the CSAD (see Annex C).

D.2 Expected response

D.2.1 Response identification
The requirements for document identification contained in ECSS--M--50 shall be
applied to the CSVP.

D.2.2 Scope and contents

The CSVP shall provide the information presented in the following sections:

27
ECSS--E--50 Part 2A
4 July 2005 ECSS
<1> Introduction
The CSVP shall contain a description of the purpose, objective, content
and the reason prompting its preparation.
<2> Applicable and reference documents
The CSVP shall list the applicable and reference documents in support to
the generation of the document.
<3> Mission description and communication system overview
The CSVP shall briefly describe:
(a) the main objectives and characteristics of the space mission, and
(b) the intended communication system implementation.
<4> Verification approach
The CSVP shall:
(a) describe the approach to the communication system verification,
(b) describe the techniques to be used for the verification, and
(c) list any special tools or facilities to be used.
<5> Verification schedule
The CSVP shall:
(a) describe the communication system verification schedule explaining
how the communication system verification schedule matches the
development schedules for both the ground segment and flight
segment of the space mission;
(b) include a list of all tools and equipment to be used for the
communication system verification activities, identifying for each
tool
(1) who is responsible for supplying it,
(2) where it is provided,
(3) the equipment configuration to use, and
(4) the duration for which it is used.
<6> Support to other verification activities
The CSVP shall describe:
(a) the tools, equipment, and facilities associated with the communica-
tion system that can be made available to support other verification
activities, such as the ground system or flight system verification;
(b) the nature of the tool, equipment, or facility;
(c) the capability of each tool;
(d) when and where each tool can be made available.
<7> Verification tests
The CSVP shall describe each verification test to be performed, including
the following information for each one:
(a) a statement of the purpose of the verification test;
(b) a detailed description of the test;
(c) a list of the tools, equipment, or facilities to perform the test;
(d) a definition of the configuration of the test environment and the unit
under test at the start of the test (i.e. pre-conditions);
(e) a description of the expected result (i.e. post-conditions);
(f) pass and fail criteria for the test.
NOTE The purpose of these test description is to ensure that
the verification tests can be repeated.

28
ECSS
ECSS--E--50 Part 2A
4 July 2005

Annex E (normative)

Communication system architectural design

document (CSADD) DRD

E.1 DRD identification

E.1.1 Requirement identification and source document
ECSS--E--50 Part 1A, requirements 5.2.3.3 and 5.2.4.3.

E.1.2 Purpose and objective

The communication system architectural design document (CSADD) describes the
architectural design of the communication system defined in the CSBD (see
Annex B).
The CSADD describes the design to the level where its functionality and operation
can be understood for the purposes of the PDR. Furthermore, the CSADD enables
the requirements for the individual system components, and the interfaces to
those components, to be elaborated so that detailed design of the components can
proceed.
The CSADD is produced by the communication system supplier to describe the
architectural design of the communication system.
The CSADD is produced for the PDR, and its acceptance at the PDR by the
communication system customer implies a commitment to proceed with the
detailed design consistent with the architecture described. As specified in
ECSS--E--50 Part 1, the CSADD is frozen after acceptance at the PDR.
The communication system architectural design document describes the high
level architecture of the communication system and is therefore derived from the
CSBD. In turn, the communication system detailed design document (CSDDD) is
derived from the CSADD.
The interfaces identified within the CSADD, both between the communication
system components, and to other external entities, are subject to tests defined in
the CSVP. The functionality and performance of the communication system
components identified in the CSADD can be the subject of specific analysis
activities in the CSAD.

29
ECSS--E--50 Part 2A
4 July 2005 ECSS
E.2 Expected response
E.2.1 Response identification
The requirements for document identification contained in ECSS--M--50 shall be
applied to the CSADD.

E.2.2 Scope and contents

The CSADD shall provide the information presented in the following sections:

<1> Introduction
The CSADD shall contain a description of the purpose, objective, content
and the reason prompting its preparation.

<2> Applicable and reference documents

The CSADD shall list the applicable and reference documents in support
to the generation of the document.

<3> Mission description and communication system overview

The CSADD shall briefly describe:
(a) the main objectives and characteristics of the space mission, and
(b) the intended communication system baseline as defined in the CSBD.

<4> Communication system architectural design

(a) The CSADD shall contain a description of the architectural design of
the communication system in a human readable format, and include
the justification of all critical architectural design decisions.
(b) Although this DRD imposes no constraints on the tools used to
elaborate the architectural design, the architectural design shall be
viewable without the use of the design tool.
(c) As a minimum, the architectural design of the communication system
shall:
(1) list each major component of the communication system,
(2) describe the function and performance of each major component
in terms of top level requirements,
(3) list and broadly describe all of the internal interfaces (i.e. inter-
faces between components of the communication system), and
(4) list and broadly describe all of the external interfaces (i.e. inter-
faces between external entities and components of the communi-
cation system).

<5> Requirement applicability matrix

This CSADD shall provide a requirement applicability matrix, including
the following information:
— requirements -- containing a list of all requirements in the CSRD plus
any derived requirements contained in the CSBD;
— applicability -- indicating the applicability of each requirement to
each major communication system component. Usually, this column
can be subdivided into a series of columns, one for each major system
component, and completed check-box style;
— notes – providing any special information associated with a given
requirement in respect of its allocation to a communication system
component.

30
ECSS
ECSS--E--50 Part 2A
4 July 2005

Annex F (normative)

Communication system detailed design

document (CSDDD) DRD

F.1 DRD identification

F.1.1 Requirement identification and source document
ECSS--E--50 Part 1A, requirements 5.2.3.3 and 5.2.4.3.

F.1.2 Purpose and objective

The communication system detailed design document (CSDDD) describes the
detailed design of the communication system, further elaborating the architec-
tural design described in the CSADD (see Annex E). The CSDDD described the
detailed design of each of the communication system components identified in the
CSADD.
The CSDDD is produced by the communication system supplier to describe the
detailed design of the communication system consistent with the architecture
described in the CSADD. It describes the detailed design of each of the major
communication system components identified in the CSADD.
The CSDDD is produced for the CDR, and its acceptance at the CDR by the
communication system customer implies a commitment to proceed with the
implementation of the system according to that detailed design.
As specified in ECSS--E--50 Part 1, the CSDDD is frozen after acceptance at the
CDR.
The communication system detailed design document describes the detailed
design of the communication system, and derives from the CSBD (see Annex B)
and CSADD (see Annex E). Specific detailed tests for the components described in
the communication system detailed design document are further described in the
CSVP (see Annex D). Any specific analysis activities to justify the detailed design
are contained in the CSAD (see Annex C).
As specified in ECSS--E--50 Part 1, the implementation or procurement of all of the
communication system components is based on the communication system
detailed design document.

31
ECSS--E--50 Part 2A
4 July 2005 ECSS
F.2 Expected response
F.2.1 Response identification
The requirements for document identification contained in ECSS--M--50 shall be
applied to the CSDDD.

F.2.2 Scope and contents

The CSDDD shall provide the information presented in the following sections:

<1> Introduction
The CSDDD shall contain a description of the purpose, objective, content
and the reason prompting its preparation.

<2> Applicable and reference documents

The CSDDD shall list the applicable and reference documents in support
to the generation of the document.

<3> Mission description and communication system overview

The CSDDD shall briefly describe:
(a) the main objectives and characteristics of the space mission, and
(b) the architectural design contained in the CSADD.

<4> Communication system detailed design

(a) The CSDDD shall contain the detailed design of the communication
system, with all critical detailed design decision justifications,
including:
(1) the requirements applicable to each of the major components of
the communication system identified in the CSADD,
(2) the detailed design of each major component of the communica-
tion system,
(3) a justification of all design decisions relating to the detailed
design of each component, and
(4) a complete description of all of the interfaces to each component.
(b) This DRD imposes no constraints on the tools used to elaborate the
detailed design, and some elements of the detailed design, that can
only be viewed with the aid of the tools used in the elaboration of the
design, may be accepted.

<5> ICDs of the major components

The CSDDD shall include the ICDs for each of the major components of the
communication system.

32
ECSS
ECSS--E--50 Part 2A
4 July 2005

Annex G (normative)

Communication system profile document (CSPD)

DRD

G.1 DRD identification

G.1.1 Requirement identification and source document
ECSS--E--50 Part 1A, requirements 5.2.3.3 and 5.2.5.3.

G.1.2 Purpose and objective

The communication system profile document (CSPD) defines the frequencies,
protocols and protocol options, address assignments, channel assignments,
spacecraft identifier assignments, space link bandwidth allocations, and onboard
bus bandwidth allocations used in the communication system, and constitutes a
formal statement of compliance of the communication system to ECSS--E--50.
The CSPD is produced by the communication system supplier as a formal
statement of the compliance of the communication system to the ECSS--E--50
requirements. The communication system profile document describes the
frequencies, protocols and protocol options, address assignments, channel
assignments, spacecraft identifier assignments, space link bandwidth allocations,
and onboard bus bandwidth allocations used in the communication system.
As specified in ECSS--E--50 Part 1, the final version of the communication system
profile document is available at FRR. Earlier versions can be produced for other
reviews.
The communication system profile document describes the frequencies, protocols
and protocol options, address assignments, channel assignments, spacecraft
identifier assignments, spacelink bandwidth allocations, and onboard bus
bandwidth allocations used in the communication system. This is a formal
statement of compliance of the communication system to ECSS--E--50 and can be
used for the establishment of interoperability agreements involving the communi-
cation system.

33
ECSS--E--50 Part 2A
4 July 2005 ECSS
G.2 Expected response
G.2.1 Response identification
The requirements for document identification contained in ECSS--M--50 shall be
applied to the CSPD.

G.2.2 Scope and contents

The CSPD shall provide the information presented in the following sections:

<1> Introduction
The CSPD shall contain a description of the purpose, objective, content
and the reason prompting its preparation.

<2> Applicable and reference documents

The CSPD shall list the applicable and reference documents in support to
the generation of the document.

<3> Mission description and communication system overview

This CSPD shall briefly describe:
(a) the main objectives and characteristics of the space mission, and
(b) the communication system to which this profile document relates.

<4> Communication system profile

This CSPD shall consist of all tables, matrices, compliance statements,
and compliance pro-formas to fully describe the characteristics of the
communication system.
NOTE This DRD imposes no constraints on the way in which this
information is presented. Generally, any standard protocols
that are used can be defined by the compliance pro-forma
associated with that protocol. For other, mission specific
characteristics such as the spacecraft identifier values,
spacelink frequencies, channel allocations, and address
assignments, it is good practice that an appropriate mission
pro-forma is defined early in the programme and populated
as the values become known.

34
ECSS
ECSS--E--50 Part 2A
4 July 2005

Annex H (normative)

Communication system operations manual

(CSOM) DRD

H.1 DRD identification

H.1.1 Requirement identification and source document
ECSS--E--50 Part 1A, requirement 5.2.3.3.

H.1.2 Purpose and objective

The communication system operations manual (CSOM) formally describes all
procedures for the operation of the communication system. The operational
procedures include normal and contingency operations. Normal operations
include procedures for spacecraft signal acquisition, loss of signal, and hand-over,
as well as communication system management activities such as address
initialization and router configuration and maintenance. Contingency operations
cover uni-directional space link (uplink only, downlink only), unexpected loss of
signal, and discontinuos signal.
The CSOM is produced by the communication system supplier to describe the
operations procedures for normal and contingency operation of the communica-
tion system.
As specified in ECSS--E--50 Part 1, the final version of the communication system
operations manual is available for FRR. Earlier versions can be prepared for other
reviews.
The communication system operations manual constitutes the user manual for the
communication system. It is used in the development of the overall space mission
operations procedures, and can be relevant to the definition of the onboard
software.

H.2 Expected response

H.2.1 Response identification
The requirements for document identification contained in ECSS--M--50 shall be
applied to the CSOM.

35
ECSS--E--50 Part 2A
4 July 2005 ECSS
H.2.2 Scope and contents
The CSOM shall provide the information presented in the following sections:

<1> Introduction
The CSOM shall contain a description of the purpose, objective, content
and the reason prompting its preparation.

<2> Applicable and reference documents

The CSOM shall list the applicable and reference documents in support to
the generation of the document.

<3> Mission description and communication system overview

The CSOM shall briefly describe:
(a) the main objectives and characteristics of the space mission, and
(b) the communication system implementation.

<4> Communication systems operations

The CSOM:
(a) shall describe the procedures used to commission the communication
system during the early phases of the mission;
(b) shall describe the communication system test procedures used to
verify the correct operation of the communication system during the
mission;
(c) shall describe all of the routine operations procedures that are used
during the mission, i.e. once the communication system is commis-
sioned and operating normally;
(d) should include any procedure for the communication system reconfi-
guration that can be expected during the mission, such as the
switch-over to a redundant communication chain, or the update of
onboard routing tables;
(e) shall describe the contingency operations procedures to be used
during abnormal operating conditions, e.g. when failures occur in the
communication system.

<5> Decommissioning procedure

This CSOM shall describe the procedures used to decommission the
communication system at the end of the mission.

<6> Additional operating procedures

The CSOM shall describe any operating procedures applicable to the
communication system not described in items <4> and <5> above.
NOTE For example, these can include procedures to extend the
capability of the communication system during the mission,
e.g. by adding spacecraft to an existing constellation.

36
ECSS
ECSS--E--50 Part 2A
4 July 2005

ECSS Change Request / Document Improvement Proposal

A Change Request / Document Improvement Proposal for an ECSS Standard may be submitted to the
ECSS Secretariat at any time after the standard’s publication using the form presented below.
This form can be downloaded in MS Word format from the ECSS Website
(www.ecss.nl, in the menus: Standards -- ECSS forms).

ECSS Change Request / Document Improvement Proposal

1. Originator’s name: 2. ECSS Document number:

Organization: 3. Date:

e-- mail:

5. Location of
4. Number. deficiency 6. Changes 7. Justification 8. Disposition
clause page
(e.g. 3.1 14)

Filling instructions:
1. Originator’s name - Insert the originator’s name and address
2. ECSS document number - Insert the complete ECSS reference number (e.g. ECSS--M--00B)
3. Date - Insert current date
4. Number - Insert originator’s numbering of CR/DIP (optional)
5. Location - Insert clause, table or figure number and page number where deficiency has been
identified
6. Changes - Identify any improvement proposed, giving as much detail as possible
7. Justification - Describe the purpose, reasons and benefits of the proposed change
8. Disposition - not to be filled in (entered by relevant ECSS Panel)

Once completed, please send the CR/DIP by e-- mail to: ecss-- secretariat@esa.int

37
ECSS--E--50 Part 2A
4 July 2005 ECSS

(This page is intentionally left blank)

38