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 document 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).

ISO draws attention to the possibility that the implementation of this document may involve the use of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s) which may be required to implement this document. However, implementers are cautioned that this may not represent the latest information, which may be obtained from the patent database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.

Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISO's adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 20, Aircraft and space vehicles, Subcommittee SC 14, Space systems and operations.

Any feedback or questions on this document should be directed to the user’s national standards body. A complete listing of these bodies can be found at www.iso.org/members.html.

Introduction

The spacecraft’s attitude and orbit control system (AOCS) is pivotal for executing the attitude and orbit management of the spacecraft, serving as a cornerstone for its basic functionalities, stable operation, and the success of spacecraft missions. This document delineates requirements and best practices for the AOCS to ensure that the spacecraft remains in a safe operational state under all circumstances, including emergencies and anomalies. It outlines the responsibilities and interactions between the ground segment and space segment, aiming to secure timely and effective detection, management, and resolution of on-board contingencies. By establishing a comprehensive framework for stable operation, this document supports mission success and enhances spacecraft safety and reliability, and equips the AOCS with the capacity to sustain or recover a stable operating state autonomously or with ground support amidst system anomalies or unforeseen failures in orbit. The ultimate goal, even under adverse conditions, is to prevent damage to the spacecraft's structure and ensure the security of its energy and propellant resources.

1 Scope

This document provides the criteria for stable on-orbit operation of the spacecraft's AOCS. It addresses the factors affecting the spacecraft's on-orbit stability by specifying principles and requirements for establishing the spacecraft AOCS's capability for stable on-orbit operation, which include:

principles for judging data validity and the requisite procedures for handling such data;
anomaly detection;
management of software and hardware failures;
safety boundary checks;
activation protocols for emergency survival modes.

This document also establishes the functional interface between on-orbit autonomy and ground-based maintenance operations, ensuring that the spacecraft maintains its intended attitude and orbit.

This document is applicable to the attitude and orbit control systems of various types of spacecraft.

2 Normative references

3 Terms and definitions

4 Stable operation general principles

4.1 General

4.2 Classification of stable operation levels

4.3 Factors affecting stable operation

4.4 Capability building for stable operation

4.5 Ground-based optimization and operational maintenance

5 Data validity assessment requirements

5.1 Basic principles of data validity judgement

5.2 Data validity assessment process

6 Anomaly detection requirements

6.1 Classification of anomaly levels

6.2 Component-level anomaly detection

6.3 System-level anomaly detection

7 Software or hardware fault handling requirements

7.1 Fault classification

7.2 Software fault handling requirements

7.3 Hardware fault handling requirements

8 Safety boundary check requirements

8.1 Principles of safety boundary checks

8.2 Requirements for safety boundary checks of spacecraft structure or mechanism

8.3 Requirements for safety boundary checks of spacecraft energy

8.4 Requirements for safety boundary checks of spacecraft propellant

9 Requirements for emergency survival modes in the spacecraft’s AOCS

9.1 Classification of emergency survival modes

9.2 Requirements for sun-oriented safety mode handling

9.3 Requirements for stop-control safety mode handling

10 Cybersecurity requirements for AOCS

10.1 General

10.2 Encryption of telemetry data

10.3 Access control for ground systems

10.4 Anomaly detection for cybersecurity breaches

10.5 Fault handling in the event of a cyber-attack

10.6 Regular security updates and testing

Bibliography