ISO/TR 18146:2020

Space systems - Space debris mitigation design and operation manual for spacecraft

This document contains information on the design and operational practices for launch vehicle orbital stages for mitigating space debris. This document provides information to engineers on what are required or recommended in the family of space debris mitigation standards to reduce the growth of space debris by ensuring that spacecraft is designed, operated, and disposed of in a manner that prevents them from generating debris throughout their orbital lifetime.

Systèmes spatiaux — Conception de réduction des débris spatiaux et manuel d’utilisation pour les engins spatiaux

General Information

• Status: Published
• Publication Date: 25-Oct-2020
• ICS: 49.140 - Space systems and operations
• Technical Committee: ISO/TC 20/SC 14 - Space systems and operations
• Drafting Committee: ISO/TC 20/SC 14 - Space systems and operations
• Current Stage: 9092 - International Standard to be revised
• Start Date: 25-Jan-2024
• Completion Date: 13-Dec-2025

Relations

• Consolidated By: ISO 7029:2017/Amd 1:2024 - Acoustics - Statistical distribution of hearing thresholds related to age and gender - Amendment 1: Correction of parameter values for estimating the hearing threshold distribution
• Effective Date: 06-Mar-2023
• Revised: ISO/DTR 18146 - Space systems - Space debris mitigation design and operation manual for spacecraft
• Effective Date: 27-Jan-2024
• Revises: ISO/TR 18146:2015 - Space systems - Space debris mitigation design and operation guidelines for spacecraft
• Effective Date: 23-Apr-2020

Overview

ISO/TR 18146:2020 - Space systems - Space debris mitigation design and operation manual for spacecraft - is a technical report by ISO that provides practical guidance for designing and operating launch vehicle orbital stages and spacecraft to mitigate space debris. Rather than setting new mandatory rules, it explains the intent and recommended practices of the family of space debris mitigation standards to help engineers reduce debris generation across a vehicle’s orbital lifetime.

Key topics and technical focus

• Design for limiting the release of objects: identification of potential released objects and engineering measures to prevent accidental or planned releases during mission life.
• Prevention of break‑up: guidance on avoiding fragmentation due to stored energy, collisions with catalogued objects, or impacts from debris and meteoroids.
• End‑of‑mission disposal: procedures for mission termination, disposal planning, orbital lifetime estimation, and design of disposal functions (including resource and reliability assurance).
• Ground safety from re‑entry: hazard analysis, controlled re‑entry design measures and notification/monitoring practices to limit risk to people and property.
• Quality and reliability assurance: lifecycle processes to maintain debris‑mitigation performance.
• Debris work across development phases: debris‑related tasks and reviews in concept, feasibility, definition, development, production, utilization and disposal phases (phase 0/A–F).
• Subsystem guidance: debris‑mitigation measures and required information for propulsion, attitude and orbit control (AOCS), power-supply, TT&C, structural and thermal subsystems.
• References to ISO 24113:2019: explains intents of related mandatory requirements and how to implement them in design and operations.

Practical applications

• Integrating space debris mitigation into spacecraft and launch‑stage design reviews and verification plans.
• Developing end‑of‑life (EOL) strategies such as controlled re‑entry, graveyard disposal or passivation of energy sources.
• Establishing operational procedures for monitoring, contingency planning, and decision‑making to extend or terminate missions.
• Preparing documentation for mission assurance, registration and regulatory compliance with international space treaties.

Who should use this standard

• Spacecraft and launch vehicle systems engineers
• Mission planners and operations teams
• Reliability, safety and quality assurance engineers
• Program managers, regulators and policy advisors working on orbital debris mitigation

Related standards

• ISO 24113:2019 (space debris mitigation requirements) - ISO/TR 18146 provides explanatory guidance and implementation context.
• Relevant international registration and space‑treaty obligations (as referenced in the report).

Keywords: ISO/TR 18146:2020, space debris mitigation, spacecraft design, end‑of‑life disposal, controlled re‑entry, launch vehicle orbital stages, ISO 24113.

Standards Content (Sample)

TECHNICAL ISO/TR
REPORT 18146
Second edition
2020-10
Space systems — Space debris
mitigation design and operation
manual for spacecraft
Systèmes spatiaux — Conception de réduction des débris spatiaux et
manuel d’utilisation pour les engins spatiaux
Reference number
©
ISO 2020
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative reference . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 1
5 System-level activities . 2
5.1 General . 2
5.2 Design for limiting the release of objects . 3
[1]
5.2.1 Intents of requirements in ISO 24113:2019 . 3
5.2.2 Work breakdown . 3
5.2.3 Identification of released objects and design measures . 4
5.2.4 Design measures . 5
5.2.5 Monitoring during operation . 5
5.2.6 Preventing failure . 5
5.3 Prevention of break-up . 5
5.3.1 General. 5
5.3.2 Break-up caused by intentional behaviour, or stored energy . 6
5.3.3 Break-up caused by a collision with catalogued objects . 7
5.3.4 Break-up caused by the impact of debris or meteoroid .11
5.4 Disposal after the end of mission to minimize interference with the protected regions .14
[1]
5.4.1 Intents of requirements in ISO 24113:2019 .14
5.4.2 Work breakdown .15
5.4.3 Procedure for determination of mission extension or termination .17
5.4.4 Disposal plan .19
5.4.5 Estimation of the orbital lifetime . .20
5.4.6 Design of the function to remove spacecraft from the protected regions .20
5.4.7 Assurance of resources for disposal manoeuvre .21
5.4.8 Reliability of disposal function up to the design life .21
5.4.9 Useful life limited items .22
5.4.10 Health assessment procedure and contingency planning .22
5.4.11 Design the monitoring system to monitor the critical parameters .23
5.4.12 Assessment of the risk of debris impact .24
5.4.13 Operational remediations .24
5.4.14 Decision-making to extend or terminate the mission .25
5.4.15 Disposal .25
5.4.16 Registration of objects launched into outer space complying with the UN
treaty .25
5.4.17 Specific subjects for GEO mission .26
5.4.18 Specific subjects for LEO mission .26
5.4.19 High elliptical orbit mission .26
5.5 Ground safety from re-entering objects .26
[1]
5.5.1 Intents of requirements in ISO 24113:2019 .26
5.5.2 Work breakdown .26
5.5.3 Identification of requirements .27
5.5.4 Hazards analysis .27
5.5.5 Design measures .28
5.5.6 Specific design for controlled re-entry in subsystem level .29
5.5.7 Notification .29
5.5.8 Conduct controlled re-entry and monitoring .29
5.6 Quality and reliability assurance .29
6 Debris-related work in the development cycle .30
6.1 General .30
6.2 Concept of debris-related work in phased planning .30
6.3 Mission analysis phase (phase 0 or pre-phase A) .34
6.3.1 General.34
6.3.2 Debris-related work .34
6.4 Feasibility phase (phase A) .35
6.5 Definition phase (phase B) .35
6.5.1 Work in phase B .35
6.5.2 Work procedure .35
6.6 Development phase (phase C) .36
6.6.1 Work in phase C .36
6.6.2 Conditions .37
6.7 Production phase (phase D) .38
6.7.1 Work in phase D .38
6.7.2 Qualification review .38
6.8 Utilization phase (phase E) .38
6.8.1 Launch preparation .38
6.8.2 Lift-off time .39
6.8.3 Initial operation .39
6.8.4 Normal operation .39
6.8.5 Decision to terminate or extension of operations .40
6.9 Disposal phase (phase F) .40
7 System-level information.41
7.1 Mission design .41
7.2 Mass allocation .41
7.3 Propellant allocation .42
7.4 Power allocation .42
8 Subsystem/component design and operation .42
8.1 General .42
8.2 Debris-mitigation measures and subsystem-level actions for realizing them .42
8.3 Propulsion subsystem .44
8.3.1 General.44
8.3.2 Debris-related design .44
8.3.3 Information of propulsion subsystems .44
8.3.4 Information in component design .46
8.4 Attitude and orbit control subsystem .48
8.4.1 Debris-related designs .48
8.4.2 Information of AOCS .48
8.4.3 Information of component design .49
8.5 Power-supply subsystem .49
8.5.1 Debris-related designs .49
8.5.2 Information of power-supply subsystems .50
8.5.3 Information of component design .51
8.6 TT&C subsystem .52
8.6.1 Debris-related designs .52
8.6.2 Information of TT&C subsystems .52
8.6.3 Information of component design .53
8.7 Structural subsystem .53
8.7.1 Debris-related design .53
8.7.2 Information of structural subsystems .53
8.8 Thermal-control subsystem .54
8.8.1 Debris-related design .54
8.8.2 Information of thermal-control subsystem .54
Bibliography .55
iv © ISO 2020 – 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 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.
This second edition cancels and replaces the second edition (ISO/TR 18146:2015), which has been
technically revised.
The main changes compared to the previous edition are as follows:
[1]
— text has been updated to be aligned with ISO 24113:2019 ;
— information has been added that the ejection of slag debris from solid rocket motors is limited newly
in low Earth orbit in addition to GEO previously;
— information relating to collision avoidance against catalogued space objects has been improved;
— information of the intention of the new requirement avoiding fragmentation caused by impact of space
debris and meteoroid, and typical assessment procedure in the world space agencies has been added;
— corresponding to the new requirement limiting the total probability of successful disposal to be at
least 0,9, the state of the art to confirm the compliance with that taken in the world space industries
and national agencies has been added;
— other information relating to the changes in ISO 24113 has been added.
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
Coping with debris is essential to preventing the deterioration of the orbital environment and ensuring
the sustainability of space activities. Effective actions are also taken to ensure the safety of those on
the ground from re-entering objects that were disposed of from low-Earth orbit.
Recently, the orbital environment has become so deteriorated by debris that action is taken to prevent
damage due to the impact. Collision avoidance manoeuvres are taken to avoid large debris (larger than
10 cm, for example), which can be observed from the ground. Spacecraft design protects against micro-
debris (even smaller than 1 mm) that can cause critical damage to vulnerable components.
[1]
ISO 24113:2019 and other ISO documents, introduced in Bibliography, were developed to encourage
debris mitigation activities.
In Clause 5, the major space debris mitigation requirements are informed.
In Clause 6, the information of life-cycle implementation of space debris mitigation related activities is
provided.
In Clause 7, the system level aspects stemming from the space debris mitigation requirements are
highlighted; while in Clause 8, the impacts at subsystem and component levels are detailed.
This document provides comprehensive information on what ISO requires to do for the design and
operation of the launch vehicles, and where such requirements and recommendations are registered in
a set of ISO documents.
vi © ISO 2020 – All rights reserved

TECHNICAL REPORT ISO/TR 18146:2020(E)
Space systems — Space debris mitigation design and
operation manual for spacecraft
1 Scope
This document contains information on the design and operational practices for launch vehicle orbital
stages for mitigating space debris.
This document provides information to engineers on what are required or recommended in the family
of space debris mitigation standards to reduce the growth of space debris by ensuring that spacecraft is
designed, operated, and disposed of in a manner that prevents them from generating debris throughout
their orbital lifetime.
2 Normative reference
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
4 Symbols and abbreviated terms
A/M area-to-mass
AOCS attitude and orbit control system
CDR critical design review
CFRP carbon-fibre-reinforced plastic
CNES Centre National d'Etudes Spatiales
CSpOC Combined Space Operations Center (USA)
DAS debris assessment software (NASA)
COTS commercial off-the-shelf
DRAMA debris risk assessment and mitigation analysis (ESA)
EOMDP end-of-mission (operation) disposal plan
ESA European Space Agency
FDIR failure detection, isolation and recovery
FMEA failure mode and effect analysis
GEO geosynchronous Earth orbit
GPSR global positioning system receiver
IADC Inter-Agency Space Debris Coordination Committee
IRU inertial reference unit
LEO low Earth orbit
MASTER meteoroid and space debris terrestrial environment reference
MIDAS MASTER (-based) impact flux and damage assessment software
NOTAM notice to airmen and notice to mariners
OLI operation time limited item
ORDEM orbital debris engineering model
PDR preliminary design review
PNF probability of no failures
QA quality assurance
QR qualification review
RCS reaction control system
SDA Space Data Association
SDR system definition review
SDMP space-debris-mitigation plan
STELA semi-analytic tool for end of life analysis (CNES)
USSTRATCOM United States strategic command
TLE two-line element set
TT&C telemetry tracking and command
UN United Nations
5 System-level activities
5.1 General
To accomplish comprehensive activities for debris mitigation and protection work, the following steps
are considered:
a) Identify debris-related requirements, recommendations and best practices.
b) Determine how to comply with these requirements, recommendations, and best practices.
c) Apply those methods early and throughout development and manufacturing to ensure sound debris
mitigation capability in the final product.
2 © ISO 2020 – All rights reserved

d) Apply appropriate quality assurance and qualification program to ensure compliance with debris
mitigation requirements
e) Apply appropriate procedures during operation/utilisation and disposal to implement proper
space debris mitigation and protection.
This subclause provides information useful for taking comprehensive action at the system level.
More detailed information for action of subsystem and component levels is provided in Clause 6. The
following specific subjects are emphasized:
— limiting the release of objects in protected orbital regions;
— preventing fragmentation in orbit (including intentional break-ups, and accidental break-ups caused
by collision with trackable objects, impact of tiny debris, and stored energy);
— proper disposal at the end of operation;
— minimization of hazard on the ground from re-entering debris;
— quality, safety and reliability assurance.
5.2 Design for limiting the release of objects
[1]
5.2.1 Intents of requirements in ISO 24113:2019
[1]
ISO 24113:2019 , 6.1 requires avoiding the intentional release of space debris into Earth orbit during
normal operations, including general objects such as fasteners, fragments from pyrotechnics, slag from
solid rocket motors, etc.
The following objects are of concern from an orbital debris mitigation standpoint:
[1]
a) objects released as directed by mission requirements (not directory indicated in ISO 24113:2019 ,
6.1.1.1, though);
[1]
b) mission-related objects, such as fasteners, apogee motor cases, etc. (ISO 24113:2019 , 6.1.1.1);
[1]
c) fragments and combustion products from pyrotechnic devices (ISO 24113:2019 , 6.1.2.1);
[1]
d) slag ejected from solid motors (ISO 24113:2019 , 6.1.2.2).
[1]
It implies that if objects are unavoidably released despite requirements in ISO 24113:2019 , 6.1.1.1,
the orbital lifetime of such objects in LEO and interference with GEO is limited as described in
[1]
ISO 24113:2019 , 6.1.1.3.
5.2.2 Work breakdown
Table 1 shows the work breakdown for the actions required to prevent the releasing of debris.
Table 1 — Work breakdown for preventing the release of objects
Process Subjects Major work
Preventive Identification a) In the mission, which releases objects required by mission
measures of released objectives, the effect on the orbital environment and the expected
objects and benefit for the mission will be assessed.”
design
b) Take preventive design to avoid releasing objects turning into space
measures
[1]
debris (ISO 24113:2019 , 6.1).
c) If objects might be released unintentionally, designers will
investigate design problems and take appropriate action during
design phase (e.g. insulators).
d) If release is unavoidable, designers will estimate the orbital lifetime
[1]
of released objects and check compliance with ISO 24113:2019 ,
6.1.1.3.
e) When applying the solid motors, the possible generation of slag and
its risk posed to space activities will be assessed.
Risk detection Monitoring a) Confirm that the orbiting characteristics of released parts are as
during estimated, if needed.
operation
b) If an unexpected object is detected, the origin of the objects will be
confirmed.
Countermeasures Preventive If an object is released unexpectedly, it will be investigated, and appro-
measures priate action will be taken to avoid repeating the release in the following
missions.
5.2.3 Identification of released objects and design measures
Identify the parts designed is released, estimate their orbital lifetimes, and determine the propriety of
their release.
a) Mission requirements that require dispersing objects
Assess the effects of proposed mission requirements on the environment. If the proposed mission
may deteriorate the environment more than justified by its benefit, system engineering may
suggest alternative approaches.
Examples are:
1) The experiment called “WESTFORD NEEDLES,” conducted in 1961 and 1963, scattered 480
million needles in orbit. More than 100 clumps of needles have been registered and many of
[2]
them are still in orbit. NASA, JSC, Orbital Debris Quarterly News, Volume 17 reported that
the legacy of Project West Ford can still be found in international policies, including the first major
United Nations accord on activities in outer space that calls for international consultations before
undertaking an experiment which might cause “potentially harmful interference with activities of
other State Parties in the peaceful exploration and use of outer space.
2) Missions that conduct intentional fragmentation (one of the major causes of deterioration of
the orbital environment).
b) Mission-related objects
Release of the following objects are avoided by appropriate mission and spacecraft design
[1]
(ISO 24113:2019 , 6.1.1):
1) fasteners for deploying and holding devices for panels or antennas;
2) nozzle closures and igniters of solid motors;
3) clamp bands that tie spacecraft and launch vehicles (usually as launch vehicle components).
4 © ISO 2020 – All rights reserved

NOTE The structural elements which support upper spacecraft used in the multi-payloads
launching missions can be released due to their unavoidability. Disposal orbit of these elements are
[1]
complied with ISO 24113:2019 , 6.1.1.2. (These elements usually belong to the launch vehicle, not the
spacecraft.)
c) Fragments and combustion products from pyrotechnic devices
Devices are selected and/or designed to avoid the production and release of the fragments of
parts or the combustion by-products. Employing vehicle components that trap all fragments and
[1]
combustion products inside for segregation (ISO 24113:2019 , 6.1.2.1).
d) Combustion products from solid motors
Solid motors are designed not to generate slag in both GEO and LEO protected regions (higher than
[1]
the manned orbit [≒approximately 400 km]). (ISO 24113:2019 , 6.1.2.2)
5.2.4 Design measures
In general, only devices that do not release parts into the space environment are selected.
CSpOC sometimes detects released cases of the apogee kick motors. The solid motors are not used for
the apogee kick motors if they generate slag. Furthermore, it is refrained from disposing the motor
cases into the orbit crossing the GEO protected region.
If parts would be released due to unavoidable reasons, the orbital lifetime of the parts and the risk
of impact on another spacecraft are assessed. The orbital lifetime can be assessed according to
[3] [3]
ISO 27852:2016 . ISO 27852:2016 does not designate a specific analysis tool but rather expects that
the users employ their reliable techniques depending upon orbit regime, so that designers can select
[3]
any tool(s) which adhere to ISO 27852:2016 approved techniques. Available simplified tools that can
be used to estimate the long term orbital lifetime are, for instance: NASA DAS (https:// orbitaldebris
.jsc .nasa .gov/ mitigation/ debris -assessment -software .html), ESA DRAMA (after creating an account
at https:// sdup .esoc .esa .int/ one can obtain a license before downloading), or CNES STELA (https://
logiciels .cnes .fr/ content/ stela ?language = en).
5.2.5 Monitoring during operation
The released objects, if they are larger than 10 cm, are confirmed with ground-based space tracking
facilities to ensure that they released as expected and that their orbital lifetimes are sufficiently short.
The space situation report provided by the CSpOC provides a good reference.
5.2.6 Preventing failure
If objects are released unexpectedly, the origin of the objects may be identified to help prevent
recurrence in future missions. Because such phenomena may indicate a malfunction, the situation is
reviewed carefully, and appropriate action taken to prevent further abnormal conditions.
5.3 Prevention of break-up
5.3.1 General
[1]
ISO 24113:2019 , 6.2 requires the prevention of break-ups caused by intentional behaviour, stored
energy, collision with catalogued objects, and impact of debris or meteoroid. In 5.3.2, the first two
subjects are discussed. The collision with catalogued objects is addressed in 5.3.3, and the impact of
debris and meteoroid in 5.3.4.
[4]
ISO 16127:2014 provides more detailed requirements and procedures for complying with them.
5.3.2 Break-up caused by intentional behaviour, or stored energy
5.3.2.1 Work breakdown for preventing orbital break-up caused by stored energy
Table 2 shows the work breakdown for preventing orbital break-up caused by stored energy.
Table 2 — Work breakdown for preventing orbital break-ups caused by stored energy
Process Subjects Major work
Preventive Mission Mission which involves the intentional break-up will be assessed to jus-
measures assessment tify its intention is essential for peaceful use of space, and its effect on
the environment can be controllable.
Identification Identify components that may cause fragmentation during or after
of sources of operation.
breakup
Design a) Missions that involve intentional break-ups are not designed.
measures
b) Take preventive design to limit the probability of accidental break-
up. Confirm it in FMEA.
c) Provide functions for to prevent break-ups after disposal.
Risk detection Monitoring a) Provide functions to monitor symptoms of break-up.
during
b) Monitor the critical parameters periodically.
operation
c) Take immediate actions if the symptom of a malfunction that can
lead to a breakup is detected.
Countermeasures Preventive Perform the disposal operations to eliminate the risk of break-ups.
measures for
break-up
5.3.2.2 Identification of the sources of break-up
[4]
For post-operation break-ups, ISO 16127:2014 identifies the following components as the most likely
causes of the break-up of spacecraft:
a) batteries in the electrical subsystem;
b) propulsion mechanisms and associated components (such as engines, thrusters, etc.);
c) pressurized components (such as tanks or bottles in the propulsion subsystems, or pneumatic
control system, and heat pipes);
d) rotating mechanisms.
5.3.2.3 Design measures
a) Intentional break-up
Missions that involve intentional break-ups are prohibited if the fragments would be ejected outer
space. This includes attacks from the ground or airplane as well as self-destruction in orbit. For the
case that there would be justification to conduct intentional destruction to improve ground safety,
[5]
IADC Space Debris Mitigation Guidelines state that it is conducted at sufficiently low altitudes so
that orbital fragments are short-lived.
b) Accidental break-up during operation
[1] –3
According to ISO 24113:2019 , the probability of accidental break-up is no greater than 10 until its
end of life. The causes of break-ups are identified in FMEA, and preventive measures are incorporated
in the design. Causes of break-ups are typically controlled by FDIR concept in system-safety
6 © ISO 2020 – All rights reserved

[4]
management. More detailed assessment procedures are presented in ISO 16127:2014 , Annex A.
For engineers wondering how to cope with rotating mechanism or complicated subsystems such as
[4]
apogee engines, ISO 16127:2014 , Annex A provides good instruction.
Note that quality and reliability management are emphasized, as well as design for debris
mitigation.
c) Break-ups that occur after the end of operation
Many break-ups have occurred long after the end of operation life (e.g. 10 years after disposal).
[1] [4]
ISO 24113:2019 and ISO 16127:2014 require detailed concepts and procedures for preventing
these break-ups. The key points are to provide venting mechanisms for residual fluids and shut-off
functions for charging lines for battery-cells, etc. Historically, for example, separating propellant
tank design combined fuel and oxygen tanks only by a common bulkhead in a way caused many
explosions.
5.3.2.4 Monitoring during operations
[1] [4]
ISO 24113:2019 , 6.2.2.5 and ISO 16127:2014 , 4.3.1 requires monitoring of critical parameters to
detect the symptoms that can lead to a) break-up, b) loss of mission capability, or c) the loss of orbit and
attitude control function, and requires immediate action when any symptoms are detected.
To prevent the occurrence of a break-up, a detection mechanism and operation procedures are designed
to monitor and facilitate immediate mitigation once any possible detection of malfunction is observed
to prevent break-ups.
5.3.2.5 Disposal operations
Sources of break-ups listed in 5.3.2.2 are mitigated (vented or operated in safe mode) according to
[4]
ISO 16127:2014 , 4.4.
5.3.3 Break-up caused by a collision with catalogued objects
[1]
5.3.3.1 Intents or requirements in ISO 24113:2019
[1]
ISO 24113:2019 , 6.2.3.1 to 6.2.3.3 require collision avoidance to prevent from generating fragments.
[1]
(Fragmentation caused by impact with orbital objects is mentioned in ISO 24113:2019 , 6.2.3.4 and
explained in 5.3.4.)
Collision with a large object (observable from the ground; typically, larger than approximately 10 cm)
causes critical damage to spacecraft and poses great risk to other intact spacecraft when thousands
of fragments are dispersed within a range of a thousand of kilometres. Therefore, the UN Space
[6] [7]
Debris Mitigation Guidelines recommend conducting the collision avoidance. ISO/TR 16158:2019
addresses best practices to evaluate and avoid collisions among orbital objects.
NOTE To conduct collision avoidance, space operators need a propulsion system (such as actuators in AOCS),
technology for conjunction assessment, and the capability to conduct avoidance and returning manoeuvres.
Each operator defines its philosophy, policy, and strategy for collision avoidance. The philosophy for collision
avoidance, including the following, is described in the system specification to avoid the risk of insufficient
propellant or manoeuvre function when needed.
a) a basic concept for collision avoidance (determination of allowable criteria for collision probability, apply
functions in design to avoid collision, prepare propellant for avoidance manoeuvre, etc.);
b) collision detection measures (including self-analysis, or analysis performed by external collision
service providers at present they are, for example CSpOC, the Space Data Association, etc.)
https:// www .space -data .org/ sda/ ;
c) criteria for notification (conjunction distance, probability of collision, etc.);
d) criteria for conducting avoidance manoeuvres (conjunction distance, features of approaching objects, etc.);
e) method of estimating the number of manoeuvres, amount of propellant for avoidance and returning
manoeuvres, and how to ensure the propellant;
f) a sequence for avoidance and returning manoeuvre (methods of avoidance, concepts for avoidance by
altitude change or phase shift);
g) how to access contact points to plan coordinated avoidance manoeuvres, data exchanging rules, etc.
5.3.3.2 General information
[7]
ISO/TR 16158:2019 describes the workflow for perceiving and avoiding collisions among orbiting
objects, the data requirements for these tasks, the techniques that can be used to estimate the
probability of collision, and guidance for executing avoidance manoeuvres.
5.3.3.3 Work breakdown
Table 3 shows the work breakdown for avoiding collisions with catalogued objects.
Table 3 — Work breakdown for avoiding collision with catalogued objects
Process Subjects Major work
Preventive Estimation of Estimate collision probability by debris population models.
measures probability
Design measures a) If the collision probability cannot be ignored, the function to avoid
collision is incorporated in design.
b) Define the criteria of decision-making for avoidance and estimate the
expected number of collision avoidance manoeuvres during mission
operations. It will be reflected in the design of the mass of propellant.
Standardize the The criteria of collision avoidance and the standard procedure for collision
procedures avoidance is documented.
Risk Receipt of warning a) If warning of close approach comes from USSTRATCOM/CSpOC, check
detection from the collision the conjunction risk and identify the approaching object in detail.
avoidance services Reconfirm that the up-to-date, authoritative orbit ephemerides are
provided to CSpOC for re-analysis.
b) Operators can also use commercial services (e.g. the Space Data
Association’s conjunction assessment process) or one provided by
other agencies.
c) Determine the necessity of collision avoidance based on the result of
re-analysis conducted by collision avoidance service and, if possible, by
internal analysis.
Internal If the operators have their own observation data and conjunction analysis
detection of risk systems, they may be capable of performing their own analysis.
a) Decide to conduct avoidance manoeuvres, if necessary.
Counter- Avoidance and
measures returning
b) Ahead of time, develop an avoidance manoeuvre plan (include return
manoeuvres
plan, if needed).
c) Communicate avoidance manoeuvre plan to collision avoidance service
and if any to the operator of the approaching spacecraft.
d) Develop the avoidance
...