ISO 23312

• Abstract:

  This document defines detailed space debris mitigation requirements and recommendations for the design and operation of unmanned spacecraft in Earth orbit. This document defines detailed requirements that are applicable to: avoiding the intentional release of space debris into Earth orbit during normal operations; avoiding break-ups in Earth orbit; disposal of a spacecraft after the end of mission; estimating the mass of the remaining usable propellant; developing and maintaining the space debris mitigation plan. NOTE This document does not cover nuclear power sources on spacecraft.

• Status: Not Published
• 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/WG 7 - Orbital Debris Working Group
• Current Stage: 6000 - International Standard under publication
• Start Date: 14-Aug-2026
• Completion Date: 03-Oct-2026

• Revises: ISO 23312:2022 - Space systems — Detailed space debris mitigation requirements for spacecraft
• Effective Date: 09-Aug-2025

Overview

ISO 23312: Space systems - Detailed space debris mitigation requirements for spacecraft is an international standard providing detailed requirements and recommendations for the design and operation of unmanned spacecraft in Earth orbit. Developed by ISO Technical Committee 20/SC 14, this standard supports space mission sustainability by minimizing the creation and impact of space debris. ISO 23312 details concrete measures to implement the high-level principles outlined in ISO 24113, covering key areas such as preventing the intentional release of debris, managing accidental break-ups, secure spacecraft disposal at end-of-life, estimating remaining usable propellant, and establishing robust space debris mitigation plans.

Key Topics

• Debris Release Prevention: Specifications to avoid unintentional release of any material or component during routine spacecraft operations, with guidelines on design choices and materials selection to minimize the risk.
• Accidental Break-Up Avoidance: Requirements addressing prevention of spacecraft failures in orbit due to stored energy sources (propellant, batteries), subsystem-specific safety protocols, and procedures for robust passivation at end of mission.
• Collision Risk Management: Guidance on conjunction assessment, collision probability evaluations, and avoidance manoeuvres throughout operational phases to reduce accidental break-ups from impacts.
• End-of-Mission Disposal: Procedures for de-orbiting or repositioning spacecraft to minimize long-term interference with protected orbital regions (LEO, GEO), including rules for stable disposal orbits and recommendations for enhancing re-entry safety.
• Propellant Estimation: Methods to estimate and monitor remaining usable propellant, incorporating uncertainty analysis and requirements for reliable onboard measurement and documentation.
• Mitigation Planning: Guidelines for developing and maintaining a comprehensive space debris mitigation plan, including break-up prevention, end-of-mission disposal, and contingency plans.

Applications

ISO 23312 offers practical value for:

• Spacecraft Designers & Manufacturers: Ensuring compliance with international best practices for debris mitigation from the outset of a project, leveraging detailed measures for design reliability and safety.
• Satellite Operators & Mission Planners: Establishing procedures for in-orbit operations to avoid accidental debris generation, periodic collision assessments, and secure disposal at the conclusion of service.
• Regulatory Bodies: Providing a technical reference for national or regional legislation and policies on space debris mitigation for unmanned spacecraft in Earth orbit.
• Space Agencies & Procurement Teams: Requiring adherence to a harmonized set of standards in contracts, supporting sustainable space operations and safeguarding the orbital environment.
• Compliance Officers: Assisting in audits and reviews by outlining explicit documentation and risk assessment processes related to mission design and disposal planning.

Related Standards

Organizations implementing ISO 23312 often reference and integrate with the following standards to ensure comprehensive space debris mitigation:

• ISO 24113: Space systems - Space debris mitigation requirements (the overarching high-level standard for debris mitigation).
• ISO 16127, ISO 16164, ISO 23339, ISO 26872: Technical standards that provide additional detailed requirements relevant to debris mitigation for spacecraft subsystems.
• ISO 16691, ISO 23129, ISO 23230: Standards for spacecraft coatings, with relevance to minimizing the risk of debris from material degradation.
• ISO 14623, ISO 24638: Guidelines for design and qualification of high-pressure vessels commonly used in spacecraft propulsion systems.
• ISO/TR 16158, ISO 11227, ISO 16126: Guidance for collision risk assessment and debris impact analysis.

By aligning with ISO 23312 and its related standards, the space industry can better protect vital orbital regions, extend mission lifespans, and contribute to the long-term sustainability of space activities.

Keywords: ISO 23312, space debris mitigation, spacecraft design, end-of-mission disposal, collision avoidance, usable propellant estimation, space sustainability, unmanned spacecraft, international space standards.

FINAL DRAFT
International
Standard
ISO/FDIS 23312
ISO/TC 20/SC 14
Space systems — Detailed space
Secretariat: ANSI
debris mitigation requirements for
Voting begins on:
spacecraft
2026-06-18
Systèmes spatiaux — exigences détaillées pour la diminution des
Voting terminates on:
debris spatiaux relatifs aux satellites
2026-08-13
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Reference number
ISO/FDIS 23312:2026(en) © ISO 2026

FINAL DRAFT
ISO/FDIS 23312:2026(en)
International
Standard
ISO/FDIS 23312
ISO/TC 20/SC 14
Space systems — Detailed space
Secretariat: ANSI
debris mitigation requirements for
Voting begins on:
spacecraft
Systèmes spatiaux — exigences détaillées pour la diminution des
Voting terminates on:
debris spatiaux relatifs aux satellites
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2026
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
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TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
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Published in Switzerland Reference number
ISO/FDIS 23312:2026(en) © ISO 2026

ii
ISO/FDIS 23312:2026(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms. 2
5 Avoiding release of space debris into Earth orbit during normal operations . 2
6 Avoiding break-ups in Earth orbit . 3
6.1 General .3
6.2 Accidental break-up caused by an on-board source of energy .3
6.2.1 General measures .3
6.2.2 Subsystem-specific measures.4
6.3 Accidental break-up caused by a collision .5
6.3.1 Collision avoidance .5
6.3.2 Assessment of the probability of structural break-up caused by impacts with
debris or meteoroid .6
7 Disposal of spacecraft after the end of mission . 6
7.1 General .6
7.2 Ensuring execution of disposal action .6
7.3 Disposal to minimize interference with the GEO protected region .7
7.3.1 General .7
7.3.2 Developing basic manoeuvre requirements for a stable disposal orbit .7
7.3.3 Developing long-term (100-year) disposal orbit characteristics .7
7.3.4 Determining the manoeuvre sequence .8
7.4 Disposal to minimize interference with the LEO protected region .8
7.4.1 General .8
7.4.2 Re-entry .8
8 Estimating mass of remaining usable propellant . 8
8.1 General .8
8.2 Uncertainty of estimation.9
8.3 Incorporating required function into spacecraft design .9
8.4 Documentation of data .10
9 Space debris mitigation plan . 10
9.1 General .10
9.2 Break-up prevention plan .11
9.3 End of mission disposal plan (EOMDP) .11
9.4 Contingency plan . 12
Annex A (informative) Procedure for estimating probability of accidental break-up .13
Annex B (informative) Examples of estimation methods .16
Annex C (informative) Deployable drag enhancement device .18
Bibliography . 19

iii
ISO/FDIS 23312:2026(en)
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 first edition (ISO 23312:2022), of which it constitutes a minor
revision. The main change is as follows:
— revision of the reference to ISO 24113.
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.

iv
ISO/FDIS 23312:2026(en)
Introduction
This document is developed to incorporate the content of ISO 16127, ISO 16164, ISO 23339, ISO 26872 and
other detailed requirements relevant to spacecraft related debris mitigation, corresponding to ISO 24113.
The purpose of this document is to enable conformance with those high-level space debris mitigation
requirements in ISO 24113 that are relevant to spacecraft.
This document acts as one of the supporting technical standards for space debris mitigation, to provide
implementation requirements and details for the top-level requirements in ISO 24113.

v
FINAL DRAFT International Standard ISO/FDIS 23312:2026(en)
Space systems — Detailed space debris mitigation
requirements for spacecraft
1 Scope
This document defines detailed space debris mitigation requirements and recommendations for the design
and operation of unmanned spacecraft in Earth orbit.
This document defines detailed requirements that are applicable to:
a) avoiding the intentional release of space debris into Earth orbit during normal operations;
b) avoiding break-ups in Earth orbit;
c) disposal of a spacecraft after the end of mission;
d) estimating the mass of the remaining usable propellant;
e) developing and maintaining the space debris mitigation plan.
NOTE This document does not cover nuclear power sources on spacecraft.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 24113, Space systems — Space debris mitigation requirements
ISO 24113:2023, Space systems — Space debris mitigation requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 24113 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
acquiring organization
organization that plans and manages the development and acquisition contracts for the space system
Note 1 to entry: The responsibilities of the acquiring organization include the engineering and technical aspects of the
space system’s design and operations.
3.2
book-keeping method
method for determining fluid consumption by monitoring flow rates and the duration of propellant
expenditure periods
ISO/FDIS 23312:2026(en)
3.3
disposal orbit
orbit in which a spacecraft resides following the completion of its disposal actions
3.4
PVT method
method for determining the remaining fluid quantity by estimating the mass of gas by deriving density in a
known volume from pressure and temperature measurements
3.5
remaining usable propellant
propellant that remains in the propellant system and that is effective for attitude and orbit control
manoeuvres excluding residuals and uncertainty
4 Symbols and abbreviated terms
ΔV delta velocity or total velocity change
EOL end of life
EOMDP end of mission disposal plan
GEO geostationary Earth orbit
LEO low Earth orbit
ṁ mass flow rate
MLI multilayer insulation
PVT pressure, volume, temperature
SDMP space debris mitigation plan
t time
5 Avoiding release of space debris into Earth orbit during normal operations
ISO 24113 specifies that a spacecraft shall be designed so as not to release space debris into Earth orbit
during normal operations. To satisfy this requirement, as a minimum, the following measures shall be taken
into account.
a) Any appendage related to spacecraft normal operations shall be designed not to be released.
NOTE 1 Appendages include items such as apogee kick propulsion devices, fasteners of holding and deployment
mechanisms, caps, hoods, heat insulation enclosures, springs, explosive bolts and related fragments.
b) Releasing parts essential for mission objectives should not pose a risk to the safety of operating
spacecraft and deteriorate the space environment.
c) Paint, MLI and surface materials that are exposed to the space environment, should be selected and
processes applied properly, to avoid flaking off from the spacecraft.
NOTE 2 The following ISO documents can help to ensure conformance:
1) ISO 16691, Thermal control coatings for spacecraft — General requirements.
2) ISO 23129, Space systems — Thermal control coatings for spacecraft — Atomic oxygen protective coating on
polyimide film.
3) ISO 23230, Space systems — Paint materials — Processes, procedures, requirements.

ISO/FDIS 23312:2026(en)
d) Programs using tethers shall take extra measures to limit the collision risk with resident space objects,
and not to be severed with a single impact of debris or meteoroid.
NOTE 3 A potential measure for a tethered system is to apply multi-strand tether, to retract the tether in the
disposal phase.
6 Avoiding break-ups in Earth orbit
6.1 General
ISO 24113 specifies requirements to avoid the accidental break-up of a spacecraft in Earth orbit both before
and after its end of life. 6.2 and 6.3 provide detailed measures to help satisfy these requirements.
6.2 Accidental break-up caused by an on-board source of energy
6.2.1 General measures
6.2.1.1 Spacecraft design
The spacecraft design measures to prevent accidental break-ups caused by on-board source of energy are as
follows.
a) The calculations to determine the probability of accidental break-up while in orbit until its end of life
shall be performed and assessed with probability levels defined in ISO 24113:2023, 7.2.2.1.
NOTE 1 Annex A provides an example of an acceptable detailed evaluation approach.
b) Measures shall be designed to ensure that all on-board sources of stored energy can be depleted or
made safe and permanently deactivated once they are no longer required for the mission operation.
NOTE 2 Source can be residual propellants, batteries, high-pressure vessels, self-destructive devices,
flywheels, and momentum wheels.
c) The design of the on-board sources of stored energy shall take into account the following influences:
1) the environmental extremes expected to be encountered during the normal operations;
2) mechanical degradation during the normal operations;
3) chemical decomposition;
4) the effect of potential failure modes of the spacecraft during the mission; and
5) what effect they have on the ability to passivate the spacecraft.
d) The robustness of the design shall be confirmed during the design review process, to ensure that
adequate reliability and quality control has been performed to inhibit any failure that can lead to a
break-up event with a probability worse than specified in ISO 24113.
e) The first issue of passivation procedures shall be established prior to the end of the design phase.
6.2.1.2 Spacecraft operations
The spacecraft in-orbit operation measures to prevent accidental break-ups caused by on-board source of
energy are as follows.
a) For the operations of the spacecraft, procedures shall be defined to allow monitoring of the relevant
parameters of each subsystem, which has been identified as a potential source of space debris
generation, in order to detect malfunctions.

ISO/FDIS 23312:2026(en)
b) The following items, as a minimum, shall be monitored from the ground, if applicable:
1) pressure and temperature in the engines, tanks, pressure vessels;
2) parameters (temperature and voltage) of batteries to detect failures;
3) parameters to detect failure modes of the orbit and attitude control system.
c) Prior to the disposal phase, the passivation procedures shall be updated to take into account any failures
that have occurred during the mission and that affect the ability to passivate the spacecraft.
d) At the time when spacecraft operation is concluded either purposefully or due to malfunction and
disposal manoeuvres have been finished, passivation shall be performed.
NOTE If a controlled re-entry is to be performed, then passivation is not necessary.
e) In the event of in-orbit malfunctions which can lead to break-up or the loss of operating function, a
contingency plan to prevent debris generation should have been studied and, where appropriate,
implemented.
6.2.2 Subsystem-specific measures
6.2.2.1 Electrical systems
The specific measures for electrical systems are as follows.
a) The performance of batteries shall be monitored and assessed in accordance with standardized
procedures to assure the safety of the mission and post-mission disposal.
NOTE 1 Standardized procedure for health assessment of lithium-ion batteries can be found in ISO/CD TR 20891
[1]
.
b) Batteries and/or electrical systems shall be designed and manufactured, both structurally and
electrically, to prevent break-ups during all orbital life.
c) Pressure increase in battery cells and assemblies, potentially leading to a break-up, shall be prevented.
NOTE 2 This can be done by mechanical measures for some types of batteries as far as it doesn’t decrease the
reliability.
d) At the end of operations, take measures to prevent re-charging to batteries, and discharge the stored
electric energy with assuring to keep necessary electric energy for following disposal action.
6.2.2.2 Propulsion systems
The specific measures for propulsion systems are as follows.
a) Pressure vessels, such as tanks and high-pressure gas bottles, shall be designed to avoid accidental
break-up caused by stored energy sources.
[2] [3]
NOTE ISO 14623 and ISO 24638 contain requirements relating to the design of pressure vessels.
b) For a bipropellant propulsion system, especially with hypergolic propellants, tanks and lines should be
designed so that any single-point failure does not cause the unplanned mixture or combustion of the
propellants.
c) Before end of life, as part of the disposal phase, the spacecraft shall have consumed or vented residual
liquid propellants and pressurized fluids, such as cold gas, liquefied gas, and propellant for the fluid-
based electric propulsion systems, which are potential sources of break-ups. Any residual liquid
propellants and pressurized fluids can be a source of break-ups also for spacecraft drifting outside
protected regions after end of life and should be consumed or vented to the maximum extent as possible
before end of life.
ISO/FDIS 23312:2026(en)
d) End of venting shall be monitored (or confirmed), if appropriate, by proper means, such as on-board
pressure sensors, fluid gauging systems, thermal sensing, attitude sensing, or any other demonstrable
means.
e) If it is not possible to vent, a sufficient safety margin to ensure no break-ups under expected post-
disposal environmental conditions shall be adopted.
f) The venting system and process shall be designed not to be prevented by the frozen propellants.
g) The venting process should be defined to take into account any potential effects on the spacecraft’s
attitude or orbit and any ground visibility issues.
h) Solid rocket motors shall only be actuated in the case that there have been no sensor indications of
motor degradation due to mission-induced damage or due to adverse environmental conditions.
i) Solid motor should not be allowed if it generates slags in the GEO and LEO protected regions.
6.2.2.3 Pressurized systems such as heat pipes/fluid loops
All pressurized systems which are typically not designed to be vented, such as heat pipes/fluid loops, shall
be designed and qualified with safety margins that prevent break-up of the spacecraft when considering
thermal effects in orbit.
NOTE Specific venting operations for this kind of pressurized systems are not required in the disposal phase.
6.2.2.4 Rotating hardware
The specific measures for rotating hardware are as follows.
a) All rotating devices, for example flywheels, reaction wheels, and momentum wheels, shall be designed so
that failure of the rotating part does not cause the break-up of the spacecraft under nominal mechanical
environmental conditions.
b) All rotating parts shall be allowed to de-spin, or stopped by termination of the power supply, at the end
of life.
6.2.2.5 Other devices
The specific measures for other devices are as follows.
a) Any other energy sources, such as pyrotechnically operated devices, shall be designed so that they do
not cause unacceptable risk of break-up and generate fragments.
b) Where this is unavoidable, the fragments shall be self-contained within the device which is affected by
break-up.
6.3 Accidental break-up caused by a collision
6.3.1 Collision avoidance
The spacecraft shall be designed and operated properly to prevent collision with trackable orbital objects
before its end of life.
a) During the mission operation, the conjunction assessment shall be conducted periodically against
potentially approaching objects based on the reliable orbit data.
b) Exchange of orbital parameters should be encouraged among spacecraft operators or space agencies,
to precisely check the close approach distance, and then determine an optimal avoidance manoeuvre
strategy for operators.
ISO/FDIS 23312:2026(en)
c) The probability of collision with approaching trackable orbital objects shall be assessed during
operation.
[4]
NOTE ISO/TR 16158 can be used to estimate the probability of collision.
d) If the risk of collision is above the threshold set by an approving agent, then the collision avoidance
manoeuvre (and/or returning manoeuvre) shall be planned and conducted appropriately, to reduce the
collision risk below the corresponding risk threshold.
6.3.2 Assessment of the probability of structural break-up caused by impacts with debris or
meteoroid
It is required to assess the probability of structural break-ups of spacecraft caused by impacts with debris
or meteoroid before its end of life.
a) The vulnerability of spacecraft against impact of space debris or meteoroid shall be assessed during the
design phase.
b) If the risk of structural break-up caused by impacts with debris is above the threshold set by an
approving agent, then the special design measures should be considered to minimize this risk.
[5] [6]
NOTE 1 ISO 11227 and ISO 16126 provide guidance for analysing the impact risk from small debris impacts
and improving the design of spacecraft.
NOTE 2 The probability of successful collision avoidance, induced from the experience and authorized by approving
agent, can be incorporated into this assessment.
NOTE 3 The estimated probability of collision with trackable object will provide information of the expected number
of collision avoidance during operation and contribute on the planning of propellant allocation for 7.2, list item c).
7 Disposal of spacecraft after the end of mission
7.1 General
ISO 24113 specifies requirements for the disposal of a spacecraft after the end of mission so as to minimize
interference with the protected regions. 7.2 to 7.4 provide detailed measures to help satisfy these
requirements.
NOTE Measures to prevent break-up, as a part of disposal action, are given in 6.2.
7.2 Ensuring execution of disposal action
The measures to ensure execution of disposal action are as follows.
a) The probability of successful disposal should be determined during the design phase, and decide to
terminate the operation taking into account the events that have occurred during the operating phase.
NOTE 1 In the case of highly eccentric orbits, considering the uncertainty in estimation of orbital lifetime, the
amount of propellant for disposal is designed to ensure conformance to the 25-year rule with a probability of
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