GeneralJERG-2-000A

SPACECRAFT DESIGN STANDARD

March 29, 2013

Revision A

Japan Aerospace Exploration Agency

JERG-2-000A

This is an English translation of JERG-2-000. Whenever there is anything ambiguous in thisdocument, the original document (the Japanese version) shall be used to clarify the intent ofthe requirement.

Disclaimer
The information contained herein is for general informational purposes only. JAXA makes nowarranty, express or implied, including as to the accuracy, usefulness or timeliness of any
information herein. JAXA will not be liable for any losses relating to the use of the information.

Published by
Japan Aerospace Exploration Agency
Safety and Mission Assurance Department
2-1-1 Sengen Tsukuba-shi, Ibaraki 305-8505, Japani

JERG-2-000A

Contents
SCOPE ............................................................................................................................ 1
RELATED DOCUMENTS ................................................................................................ 1
2.1
Applicable Documents.............................................................................................. 1
3. DEFINITION OF TERMS ................................................................................................. 1
4. RELATIONSHIP BETWEEN LIFECYCLE AND DESIGN STANDARD OF
SPACECRAFTS .............................................................................................................. 3
5. MEANING AND STRUCTURE OF DESIGN STANDARD ................................................ 4
6. APPLICATION OF DESIGN STANDARD ........................................................................ 5
1.
2.

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JERG-2-000A

1.

SCOPE

The primary purpose of this standard is to provide the technical information necessary
for designing and developing satellites and probes in the Japan Aerospace Exploration
Agency (hereinafter referred to as “JAXA”). Much of the technical information on thedesign and development of spacecraft program generally does not depend on thedevelopment organizations or companies. Therefore, this standard was established withthe expectation of being applied not merely in JAXA but in other organizations andcompanies for the designing and development of spacecraft programs.
This standard refers to the purpose of the mission, establishment and system designof requirements and specification, product definition, manufacturing, verification, operationand termination of the JAXA-developed spacecraft systems. As these activities areimplemented not only by JAXA but also by the cooperative institutes and contractors, it isvital to properly conform to the activities performed by JAXA such as systems engineering,and safety and mission assurance etc.
This standard was developed based on the technical information obtained fromaccumulated experience, data and research achievements in JAXA (former NASDA, ISASand NAL) with the intention to be consistent with the Aerospace Standard promoted by theInternational Organization for Standardization (ISO) as much as possible.

2.

RELATED DOCUMENTS

2.1

Applicable Documents(1) Safety and Mission Assurance Department Director Notification 16-1
Management procedure for the technical standards

3.

DEFINITION OF TERMS(1) Spacecraft
The general term of unmanned satellites and space probes.
(2) Design Standard
A document providing the standard technical information for designingspacecrafts. The technical information is gathered through past experience,research and analysis and is most rational at the time.
(3) Mission
The purpose of launching spacecrafts.
(4) SystemAn assembly of hardware and software to achieve the specified mission. It may
include human elements.
(5) Subsystem
An element of a system. A subsystem is an assembly of hardware and software
which provides a certain specified function or performance.
(6) Component
An element of system or subsystem. A component is composed of some parts,
devices and structures to have a certain function.

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JERG-2-000A(7) PartA single or a combination of multiple parts which generally could not bedisassembled without destroying it.
(8) Mission Assurance
An operation action performed throughout the development and operation ofspacecraft in order to ensure the mission success.
(9) Reliability
A property that achieves mission success within the specified mission period
under the space environment.
(10) Safety
The property that prevents spacecrafts and its components from inflicting
damage on human during the development, launch and operation of thespacecrafts and components.
(11) Systems Engineering
A series of technical methodology and activity to define the spacecraft mission
and the spacecraft system which can achieve the specified mission, and topromote the development under the constraints of launch period anddevelopment budget.
(12) Program
An overall systematic program and set of projects to achieve specific purposesor missions.
(13) Project
A fixed-term activity set as a means to achieve the mission and implemented by
the time-limited organization with the specific resources and time constraints.
(14) Design Review
A formal review performed at an appropriate time during the design work or
evaluation tests in order to confirm that the design appropriately meets therequirements and to ensure the transition to the next stage.
(15) Development Specification
A specification created in the beginning of design phase in order to specify therequirements for the design, manufacturing, test and evaluation of the item.
(16) Termination
The act of disposal or collection of spacecraft appropriately implemented at theend of its operation.

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4.

RELATIONSHIP BETWEEN LIFECYCLE OF SPACECRAFTS AND DESIGNSTANDARD

The life cycle of a spacecraft starts with defining its mission, then moves into thedesign, manufacturing and launch of the spacecraft to realize the mission, followed by theoperation in space and finally ends with the termination after operation.
Designing is an activity to analyze the defined mission requirements and determine thephysical and functional properties of various elements such as spacecraft systems,subsystems and components to realize the mission under the constraints of launch period
and development budget. Among these design activities, design standard aims to be
utilized in the system definition and the design of subsystems and components. For
designing the subsystems and components, it is important to give due consideration to thesubsequent activities of manufacturing, tests and operation, mission accomplishment,
ensuring of safety and reliability and mission assurance.

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5.

MEANING AND STRUCTURE OF DESIGN STANDARD

A design standard is a document providing the standard technical information for
designing spacecrafts. The technical information is gathered through past experience,research and analysis and is most rational at the time. In other words, it is not just a
document structure but a scheme to correct and analyze information and keep giving
feedbacks after the necessary tests and evaluations. Therefore, there shall be a scheme
to reflect the experience, development, investigation, evaluation and acquired results fromindividual projects into the design standard.
As the design standard was created based on past experiences and researchachievements, the understanding of the standard will avoid overlapping investment in dataacquisition and prevent the occurrence of similar failures, which accordingly contributes tothe reduction of development period and cost.
The document structure of design standard is organized into four levels as describedbelow.
Level 1: A top level document defining the overall policy and structure of whole
design standards. The identification number is JERG-2-000.
Level 2: The level 2 documents define the general requirements, structure andspecific technical requirements in the specific technical fields.
The design standards for the specific technical fields shall be as follows.
System Design Standard(ID No.: JERG-2-100)
Electrical Design Standard(ID No.: JERG-2-200)
Mechanical System Design Standard (ID No.: JERG-2-300)
Communication Design Standard(ID No.: JERG-2-400)
Control System Design Standard(ID No.: JERG-2-500)
Software Development Standard(ID No.: JERG-2-600)
Operational Design Standard(ID No.: JERG-2-700)
Level 3: The level 3 documents define requirements for specific technical matters.
ID numbers shall be assigned by adding numbers specific for eachtechnical matter to the ID numbers assigned for the level 2 documents.
Level 4: The level 4 documents provide explanations, procedures, tools, data andrelated information of specific technical matters to be the compliment of theabove documents. ID number shall be assigned as specified in level 3.

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6.

APPLICATION OF DESIGN STANDARD

As specified in chapters 3 and 5, the design standards provide the most rational
technical information to be a design guideline or engineering method for the spacecraft
development. Therefore, it shall be properly utilized for the development of spacecraft
programs. More specifically, the technical information contained in design standards shallbe fully understood, including its backgrounds and limitations, and utilized in the mannermost appropriate for the development conditions of each project.
During the activities in the definition phase at the early stage of project (prior to System
Design Review(SDR)), it is important to consider the utilization of design standards.
Especially, it is essential to understand the useful information to determine whether thedevelopment is achievable with the existing technology or to define which technology shallbe newly developed and acquired.
After the project starts (following to the SDR), development shall be promoted
considering the utilization of design standards in accordance with the development policy.
Since the required mission and its scale differ from project to project, it is important toselect specific design standards or part of the standard appropriate for each project basedon the requirements of mission or others.
In particular, if the application of design standards (or part of the standards) is decided
after considering the utilization of each design standards, the design standards shall bespecified as applicable documents in the preceding documents in the project document
structure such as development specification, development specification (draft) or systemdesign document (hereinafter correctively referred to as “development specifications”).
Alternatively, if the design requirement, design criterion or other equivalent document(hereinafter correctively referred to as “design criteria to be specified as applicabledocument in the development documents are prepared in each project, the technicalinformation contained in the design standard shall be properly reflected in the design
criteria. If there are any adequate design grounds (i.e. other design standards or new
insights given by recent experiments) other than the standards in this design standard
structure, they can be reflected in the design criteria used in the project. It shall berecognized that following up the process for utilizing design standards in writing isvaluable in promoting projects or maintaining the design standards based on the latest
technologies.
During design reviews conducted in each phase by JAXA or contractor involved inprojects, the adequacy of the application of the design standard or its utilization throughthe design criteria shall be reviewed.
In the review at the termination stage, the original design is reviewed as well as theaccuracy of its operation. As a result of the application of the design standard or its
operation through the design criteria, the revision of existing design standards or
establishment of new design standards shall be proposed. This proposal is essential
activities to promote and maintain the proper utilization of design standards.

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