ISO 24113:2023

ISO/TC 20/SC 14
ISO/FDIS 24113:20222023(E)
Secretariat: ANSI
Date: 2023-01-12
Space systems — Space debris mitigation requirements
Systèmes spatiaux — Exigences de mitigation des débris spatiaux

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ISO/FDIS 24113:20222023(E)
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ISO/FDIS 24113:20222023(E)
Contents Page
Foreword . iv
Introduction. vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 5
4.1 Symbols . 5
4.2 Abbreviated terms . 5
5 General . 6
6 Protected regions . 6
6.1 General . 6
6.2 LEO protected region . 7
6.3 GEO protected region . 7
7 Technical requirements . 7
7.1 Restricting the intentional release of space debris into Earth orbit during normal
operations . 7
7.1.1 General . 7
7.1.2 Space debris from pyrotechnics and solid rocket motors . 8
7.2 Avoiding break-ups in Earth orbit . 8
7.2.1 Intentional break-up . 8
7.2.2 Accidental break-up caused by an on-board source of energy . 8
7.2.3 Accidental break-up caused by a collision . 9
7.3 Disposal of a spacecraft or launch vehicle orbital stage after the end of mission so as to
minimize interference with the protected regions . 9
7.3.1 Provisions for successful disposal . 9
7.3.2 Disposal to minimize interference with the GEO protected region . 10
7.3.3 Disposal to minimize interference with the LEO protected region . 10
7.3.4 Re-entry . 11
8 Planning requirements . 12
8.1 General . 12
8.2 Space debris mitigation plan . 12
Annex A (informative) Post-launch life cycle phases of a launch vehicle or spacecraft . 13
Bibliography . 15
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ISO/FDIS 24113:20222023(E)
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 fourth edition cancels and replaces the third edition (ISO 24113:2019), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— the addition of a term and definition for the "expected number of casualties per re-entry" to replace
the term "casualty risk,";
— the modification of definitions for the terms "disposal phase, ", "Earth orbit, ", "end of life, ", "end of
mission, ", "passivate," and "probability of successful disposal.";
— the applicability of requirements in this document with respect to a space object that enters an
unbound Keplerian orbit or leaves Earth orbit,;
— the modification of a requirement relating to space debris left in Earth orbit by a launch vehicle after
normal operations,;
— minor changes to two of the requirements relating to accidental break-up caused by an on-board
source of energy,;
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ISO/FDIS 24113:20222023(E)
— changes to a requirement and noteNOTE concerning the assessment of the probability of impact-
induced break-up of a spacecraft,;
— the modification of a requirement and addition of a noteNOTE relating to the assessment of the
probability that an impact will prevent the successful disposal of a spacecraft,;
— the modification of a requirement and addition of a noteNOTE relating to the need for disposal
capability/probability reassessment before extending the mission lifetime of a spacecraft,;
— the addition of notesNOTEs pointing out the need for and potential benefit of reducing orbital
lifetime significantly below 25 years in the LEO protected region,;
— the addition of a noteNOTE concerning the collision probability associated with a deployable device
that augments the orbital decay of a spacecraft or launch vehicle orbital stage in the LEO protected
region,;
— the modification of a requirement relating to the assessment of the hazard caused by ground impact
of any objects that are expected to survive re-entry,;
— the specification of a threshold for the expected number of casualties during the re-entry of a
spacecraft or launch vehicle orbital stage, and the addition of supplementary notes,NOTEs;
— the addition of a noteNOTE concerning the listed contents of the Space Debris Mitigation Plan,space
debris mitigation plan;
— minor modifications to the two figures in Annex A,;
— updates to the Bibliography.
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.
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ISO/FDIS 24113:20222023(E)
Introduction
Space debris comprises all objects of human origin in Earth orbit or re-entering the atmosphere,
including fragments and elements thereof, that no longer serve a useful purpose. The growing population
of these objects poses an increasing hazard to mankind’s use of space. In response to this problem, there
is international consensus that space activities need to be managed to minimize collision risks among
space objects and casualty risks associated with atmospheric re-entry of such objects. This consensus is
embodied in space debris mitigation guidelines published by organizations such as the International
[ [1] ] [2][3]
Telecommunication Union (ITU) ), , the Inter-Agency Space Debris Coordination Committee (IADC)
[ [4] ]
and the United Nations (UN) ). . The transformation of debris mitigation guidelines into engineering
practice is a key purpose of this document.
[5]
The importance of this document can be seen within the context of four UN treaties that were
established under the United Nations Committee on the Peaceful Uses of Outer Space (UNCOPUOS) to
govern the involvement of nations in space activities. These are the Outer Space Treaty, the Liability
Convention, the Registration Convention and the Rescue Agreement. Through some of these treaties, a
launching State has total liability for damage caused by its spacecraft or launch vehicle orbital stages (or
any parts thereof) on the surface of the Earth or to aircraft in flight, as well as in outer space where fault
can be proven.
All countries are encouraged to abide by these international agreements in order not to endanger or
constrain existing and future activities in space. A launching State can choose to appoint licensing or
regulatory authorities to administer its approach for complying with the above-mentioned UN treaties. In
several launching States, these authorities have implemented national legislation to enforce the UN
treaties. Such legislation can include the mitigation of space debris. Some launching States meet their
obligations by appointing non-regulatory government bodies, such as national space agencies, to provide
the necessary guidelines or requirements, including those for space debris mitigation.
The general aim of space debris mitigation is to reduce the growth of space debris by ensuring that
spacecraft and launch vehicle orbital stages are designed, operated and disposed of in a manner that
prevents them from generating debris throughout their orbit lifetime. Another aim of space debris
mitigation is to ensure that space objects re-entering the Earth’s atmosphere cause no harm. These aims
are achieved by the following actions:
a) avoiding the intentional release of space debris into Earth orbit during normal operations;
b) avoiding break-ups in Earth orbit;
c) removing spacecraft and launch vehicle orbital stages from protected orbital regions after the end of
mission;
d) performing the necessary actions to minimize the risk of collision with other space objects;
e) reducing the risks associated with re-entry, e.g. to people, property and the Earth's environment.
Such actions are especially important for a spacecraft or launch vehicle orbital stage that has one or more
of the following characteristics:
— has a large collision cross-section;
— remains in orbit for many years;
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ISO/FDIS 24113:20222023(E)
— operates near manned mission orbital regions;
— operates in highly utilized regions, such as protected regions;
— operates in regions of high debris population.
This document transforms these objectives into a set of high-level debris mitigation requirements.
Methods and processes to enable conformance with these requirements are provided in a series of lower-
level implementation standards.
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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 24113:20222023(E)

Space systems — Space debris mitigation requirements
1 Scope
This document defines the primary space debris mitigation requirements applicable to all elements of
unmanned systems launched into, or passing through, near-Earth space, including launch vehicle orbital
stages, operating spacecraft and any objects released as part of normal operations.
The requirements contained in this document are intended to reduce the growth of space debris by
ensuring that spacecraft and launch vehicle orbital stages are designed, operated and disposed of in a
manner that restricts them from generating debris throughout their orbit lifetime. The requirements are
also intended to reduce the casualty risk on ground associated with atmospheric re-entry of space
objects.
This document is the top-level standard in a family of standards addressing space debris mitigation. It is
the main interface for the user, bridging between the primary space debris mitigation objectives and a set
of lower level standards and technical reports that support conformance. The lower-level documents
contain detailed requirements and implementation measures associated with the high-level requirements
in this document.
42 Normative references
There are no normative references in this document.
53 Terms and definitions
For the purposes of this document, the following terms and definitions 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
approving agent
entity from whom approval is sought for the implementation of space debris (3.23) mitigation
requirements with respect to the procurement of a spacecraft (3.25), or its launch, or its operations in
outer space, or its safe re-entry (3.22), or a combination of those activities
EXAMPLE Regulatory or licensing authorities; national or international space agencies; other delegated
organizations.
3.2
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ISO/FDIS 24113:20222023(E)
break-up
event that completely or partially destroys an object and generates space debris (3.23)
3.3
controlled re-entry
type of re-entry (3.22) where the time of re-entry is sufficiently controlled so that the impact of any
surviving debris on the surface of the Earth is confined to a designated area
Note 1 to entry: The designated area is usually an uninhabited region such as an ocean.
3.4
disposal
actions performed by a spacecraft (3.25) or launch vehicle orbital stage (3.13) to permanently reduce its
chance of accidental break-up (3.2) and to achieve its required long-term clearance of the protected
regions (3.21)
Note 1 to entry: Actions can include removing stored energy and performing post-mission orbital manoeuvres.
3.5
disposal manoeuvre
action of moving a spacecraft (3.25) or launch vehicle orbital stage (3.13) to a different orbit as part of its
disposal (3.4)
3.6
disposal phase
interval between the end of mission (3.9) of a spacecraft (3.25) or launch vehicle orbital stage (3.13) and
its end of life (3.8)
3.7
Earth orbit
bound or unbound Keplerian orbit with Earth at a focal point, or Lagrange point orbit which includes
Earth as one of the two main bodies
3.8
end of life
instant when a spacecraft (3.25) or launch vehicle orbital stage (3.13)
a) is permanently turned off, nominally as it completes its disposal phase (3.6),
b) completes its manoeuvres to perform a controlled re-entry (3.3), or
c) can no longer be controlled by the operator
Note 1 to entry: See Annex A.
3.9
end of mission
instant when a spacecraft (3.25) or launch vehicle orbital stage (3.13)
a) completes the tasks or functions for which it has been designed, other than its disposal (3.4),
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ISO/FDIS 24113:20222023(E)
b) becomes incapable of accomplishing its mission (3.15), or
c) has its mission permanently halted through a voluntary decision
Note 1 to entry: See Annex A.
3.10
expected number of casualties per re-entry
DEPRECATED: re-entry casualty risk
number of people who are predicted to be killed or seriously injured by the re-entry (3.22) of a space
object (3.24)
Note 1 to entry: The medical profession has defined a number of different injury scoring systems to distinguish
the severity of an injury. Broadly, a serious injury is one of such severity that hospitalisation is required.
3.11
geostationary Earth orbit
GEO
Earth orbit (3.7) having zero inclination, zero eccentricity, and an orbital period equal to the Earth's
sidereal rotation period
3.12
launch vehicle
DEPRECATED: launcher
system designed to transport one or more payloads into outer space
3.13
launch vehicle orbital stage
complete element of a launch vehicle (3.12) that is designed to deliver a defined thrust during a dedicated
phase of the launch vehicle’s operation and achieve orbit
Note 1 to entry: Non-propulsive elements of a launch vehicle, such as jettisonable tanks, multiple payload
structures or dispensers, are considered to be part of a launch vehicle orbital stage while they are attached.
3.14
launching State
State that launches or procures the launching of a spacecraft (3.25), or State from whose territory or
facility a spacecraft is launched
[5]
Note 1 to entry: This definition is consistent with the definition in the UN Liability Convention and the UN
[6]
General Assembly’s Resolution 59/115 on the notion of the launching State .
3.15
mission
set of tasks or functions to be accomplished by a spacecraft (3.25) or launch vehicle orbital stage (3.13),
other than its disposal (3.4)
3.16
mission lifetime extension
postponement of the previously defined end of mission (3.9)
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ISO/FDIS 24113:20222023(E)
3.17
normal operations
execution of the planned tasks or functions for which a spacecraft (3.25) or launch vehicle orbital stage
(3.13) was designed
Note 1 to entry: Normal operations include the disposal phase (3.6).
3.18
orbit lifetime
elapsed time between an orbiting space object’s (3.24) initial or reference position and its re-entry (3.22)
Note 1 to entry: Examples of "initial position" are the injection into orbit of a spacecraft (3.25) or launch vehicle
orbital stage (3.13), or the instant when space debris (3.23) is generated. An example of a "reference position" is the
orbit of a spacecraft or launch vehicle orbital stage at the end of mission (3.9).
3.19
passivate
act of permanently depleting, irreversibly deactivating, or making safe all on-
board sources of stored energy capable of causing an accidental break-up (3.2)
Note 1 to entry: Passivation is an effective measure for significantly reducing the chance of an accidental
explosion that can generate space debris (3.23).
Note 2 to entry: Propellant tanks, batteries, high-pressure vessels, self-destruct devices, flywheels and momentum
wheels are examples of on-board sources of stored energy capable of causing an accidental break-up. It is preferable
to passivate such items as soon as they are no longer required for mission operations or post-mission disposal (3.4).
Note 3 to entry: A safe level of passivation is reached when any remaining stored energy cannot be expected to
cause an accidental break-up.
Note 4 to entry: In the event of a collision, a passivated space object (3.24) is likely to create fewer space debris
than a non-passivated space object.
3.20
probability of successful disposal
probability that a spacecraft (3.25) or launch vehicle orbital stage (3.13) is able to complete all of the
actions associated with its disposal (3.4)
Note 1 to entry: This probability is usually assessed before the launch of a spacecraft or launch vehicle orbital
stage. It can also be reassessed after launch taking into consideration any changes in the operational status of
hardware. This is particularly important when deciding whether to extend the mission (3.15) lifetime or postpone
the end of life (3.8).
Note 2 to entry: The assessment of this probability includes consideration of uncertainties in the availability of
resources, such as propellant, required for the disposal.
Note 3 to entry: The assessment of this probability can include consideration of the inherent reliability of
equipment that is necessary to conduct the disposal, monitoring of the equipment, and operational remediation of
any observed degradation or failure of the equipment.
3.21
protected region
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ISO/FDIS 24113:20222023(E)
region in outer space that is protected with regard to the generation of space debris (3.23) to ensure its
safe and sustainable use in the future
3.22
re-entry
permanent return of a space object (3.24) into the Earth’s atmosphere
Note 1 to entry: Several alternative definitions are available for the delineation of a boundary between the Earth’s
atmosphere and outer space.
3.23
space debris
DEPRECATED: orbital debris
objects of human origin in Earth orbit (3.7) or re-entering the atmosphere, including fragments and
elements thereof, that no longer serve a useful purpose
Note 1 to entry: Spacecraft (3.25) in reserve or standby modes awaiting possible reactivation are considered to
serve a useful purpose.
3.24
space object
object of human origin which has reached outer space
3.25
spacecraft
system designed to perform a set of tasks or functions in outer space, excluding launch vehicle (3.12)
64 Symbols and abbreviated terms
6.14.1 Symbols
2 −1
A/m aspect area to dry mass ratio (m kg )
C solar radiation pressure coefficient (0 < C < 2)
R R
Z altitude measured with respect to a spherical Earth whose radius is 6 378 km
ZGEO altitude of the geostationary Earth orbit with respect to a spherical Earth whose radius is
6 378 km
ΔH change in altitude (km)
6.24.2 Abbreviated terms
GEO geostationary Earth orbit
LEO low Earth orbit
LV launch vehicle
S/C spacecraft
SDMP space debris mitigation plan
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ISO/FDIS 24113:20222023(E)
5 General
The requirements contained in this document are intended to reduce the growth of space debris by
ensuring that spacecraft and launch vehicle orbital stages are designed, operated and disposed of in a
manner that restricts them from generating debris throughout their orbit lifetime. The requirements are
also intended to reduce the casualty risk on ground associated with atmospheric re-entry of space
objects.
This document is the top-level standard in a family of standards addressing space debris mitigation. It is
the main interface for the user, bridging between the primary space debris mitigation objectives and a set
of lower level standards and technical reports that support conformance. The lower-level documents
contain detailed requirements and implementation measures associated with the high-level requirements
in this document.
76 Protected regions
7.16.1 General
The requirements in this document are concerned with limiting the production of space debris in Earth
orbit. Particular emphasis is placed on the LEO and GEO regions, which are considered as protected
regions with regard to the generation of space debris (see Figure 1). This is necessary to ensure their safe
and sustainable use in the future.


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ISO/FDIS 24113:20222023(E)
Key
1 Earth
2 equatorial plane
3 GEO protected region
4 LEO protected region
NOTE The dimensions in the figure are not to scale.
Figure 1 — Three-dimensional view of the protected regions around the Earth
The requirements in this document do not apply to a space object that enters an unbound Keplerian orbit
or leaves Earth orbit, provided that for at least 100 years after doing so:
a) the space object does not cross the protected regions;
b) the expected number of casualties from the space object’s re-entry is assessed to be less than the
threshold set in 67.3.4.3.
7.26.2 LEO protected region
[2]
The LEO protected region, as defined by the IADC and illustrated in Figure 1, is a complete spherical
shell that extends from the surface of a spherical Earth with an equatorial radius of 6 378 km up to an
altitude, Z, of 2 000 km.
7.36.3 GEO protected region
[2]
The GEO protected region, as defined by the IADC and illustrated in Figure 1, is a segment of a spherical
shell with the following characteristics:
a) lower altitude: geostationary altitude minus 200 km;
b) upper altitude: geostationary altitude plus 200 km;
c) latitude sector: 15° south ≤ latitude ≤ 15° north,
where geostationary altitude (Z ) is approximately 35 786 km, i.e. the altitude of the geostationary
GEO
Earth orbit above a spherical Earth with an equatorial radius of 6 378 km.
87 Technical requirements
8.17.1 Restricting the intentional release of space debris into Earth orbit during normal
operations
8.1.17.1.1 General
67.1.1.1 Spacecraft shall be designed so as not to release space debris into Earth orbit during normal
operations, other than space debris from pyrotechnics and solid rocket motors.
67.1.1.2 The total number of launch vehicle orbital stages and space debris objects left in Earth orbit
by a launch vehicle during normal operations, other than space debris from pyrotechnics and solid rocket
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ISO/FDIS 24113:20222023(E)
motors, shall be limited to one for the launch of a single spacecraft and two for the launch of multiple
spacecraft.
67.1.1.3 Space debris left in Earth orbit by a launch vehicle after normal operations, other than space
debris from pyrotechnics and solid rocket motors, shall satisfy the following conditions:
a) remain outside the GEO protected region for at least 100 years;
b) have an orbit lifetime of less than 25 years if released into an orbit that lies within or crosses the LEO
protected region within 100 years.
NOTE For condition b) the aim is to achieve an orbit lifetime of much less than 25 years.
8.1.27.1.2 Space debris from pyrotechnics and solid rocket motors
67.1.2.1 Pyrotechnic devices shall be designed so as not to release space debris larger than 1 mm in
their largest dimension into Earth orbit.
67.1.2.2 Solid rocket motors shall be designed and operated so as not to release space debris larger
than 1 mm in their largest dimension into the LEO and GEO protected regions.
NOTE The main aim of this requirement is to limit the generation of slag debris ejected into Earth orbit during
the final phase of combustion. Slag debri
...

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 24113
ISO/TC 20/SC 14
Space systems — Space debris
Secretariat: ANSI
mitigation requirements
Voting begins on:
2023-01-27
Systèmes spatiaux — Exigences de mitigation des débris spatiaux
Voting terminates on:
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BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 24113:2023(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. © ISO 2023

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ISO/FDIS 24113:2023(E)
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 24113
ISO/TC 20/SC 14
Space systems — Space debris
Secretariat: ANSI
mitigation requirements
Voting begins on:
Systèmes spatiaux — Exigences de mitigation des débris spatiaux
Voting terminates on:
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NATIONAL REGULATIONS. © ISO 2023

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ISO/FDIS 24113:2023(E)
Contents Page
Foreword .iv
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms.4
4.1 Symbols . 4
4.2 Abbreviated terms . 4
5 General . 5
6 Protected regions. 5
6.1 General . 5
6.2 LEO protected region . 6
6.3 GEO protected region . 6
7 Technical requirements . 6
7.1 Restricting the intentional release of space debris into Earth orbit during normal
operations . 6
7.1.1 General . 6
7.1.2 Space debris from pyrotechnics and solid rocket motors . 6
7.2 Avoiding break-ups in Earth orbit . 7
7.2.1 Intentional break-up . 7
7.2.2 Accidental break-up caused by an on-board source of energy . 7
7.2.3 Accidental break-up caused by a collision . 7
7.3 Disposal of a spacecraft or launch vehicle orbital stage after the end of mission so
as to minimize interference with the protected regions . 8
7.3.1 Provisions for successful disposal . . 8
7.3.2 Disposal to minimize interference with the GEO protected region . 8
7.3.3 Disposal to minimize interference with the LEO protected region . 9
7.3.4 Re-entry . 9
8 Planning requirements .10
8.1 General . 10
8.2 Space debris mitigation plan . 10
Annex A (informative) Post-launch life cycle phases of a launch vehicle or spacecraft .11
Bibliography .12
iii
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ISO/FDIS 24113:2023(E)
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 fourth edition cancels and replaces the third edition (ISO 24113:2019), which has been technically
revised.
The main changes are as follows:
— the addition of a term and definition for "expected number of casualties per re-entry" to replace the
term "casualty risk";
— the modification of definitions for the terms "disposal phase", "Earth orbit", "end of life", "end of
mission", "passivate" and "probability of successful disposal";
— the applicability of requirements in this document with respect to a space object that enters an
unbound Keplerian orbit or leaves Earth orbit;
— the modification of a requirement relating to space debris left in Earth orbit by a launch vehicle after
normal operations;
— minor changes to two of the requirements relating to accidental break-up caused by an on-board
source of energy;
— changes to a requirement and NOTE concerning the assessment of the probability of impact-induced
break-up of a spacecraft;
— the modification of a requirement and addition of a NOTE relating to the assessment of the probability
that an impact will prevent the successful disposal of a spacecraft;
— the modification of a requirement and addition of a NOTE relating to the need for disposal capability/
probability reassessment before extending the mission lifetime of a spacecraft;
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ISO/FDIS 24113:2023(E)
— the addition of NOTEs pointing out the need for and potential benefit of reducing orbital lifetime
significantly below 25 years in the LEO protected region;
— the addition of a NOTE concerning the collision probability associated with a deployable device
that augments the orbital decay of a spacecraft or launch vehicle orbital stage in the LEO protected
region;
— the modification of a requirement relating to the assessment of the hazard caused by ground impact
of any objects that are expected to survive re-entry;
— the specification of a threshold for the expected number of casualties during the re-entry of a
spacecraft or launch vehicle orbital stage, and the addition of supplementary NOTEs;
— the addition of a NOTE concerning the listed contents of the space debris mitigation plan;
— minor modifications to the two figures in Annex A;
— updates to the Bibliography.
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.
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ISO/FDIS 24113:2023(E)
Introduction
Space debris comprises all objects of human origin in Earth orbit or re-entering the atmosphere,
including fragments and elements thereof, that no longer serve a useful purpose. The growing population
of these objects poses an increasing hazard to mankind’s use of space. In response to this problem, there
is international consensus that space activities need to be managed to minimize collision risks among
space objects and casualty risks associated with atmospheric re-entry of such objects. This consensus
is embodied in space debris mitigation guidelines published by organizations such as the International
[1] [2]
Telecommunication Union (ITU), the Inter-Agency Space Debris Coordination Committee (IADC)
[3] [4]
and the United Nations (UN). The transformation of debris mitigation guidelines into engineering
practice is a key purpose of this document.
[5]
The importance of this document can be seen within the context of four UN treaties that were
established under the United Nations Committee on the Peaceful Uses of Outer Space (UNCOPUOS) to
govern the involvement of nations in space activities. These are the Outer Space Treaty, the Liability
Convention, the Registration Convention and the Rescue Agreement. Through some of these treaties, a
launching State has total liability for damage caused by its spacecraft or launch vehicle orbital stages
(or any parts thereof) on the surface of the Earth or to aircraft in flight, as well as in outer space where
fault can be proven.
All countries are encouraged to abide by these international agreements in order not to endanger or
constrain existing and future activities in space. A launching State can choose to appoint licensing or
regulatory authorities to administer its approach for complying with the above-mentioned UN treaties.
In several launching States, these authorities have implemented national legislation to enforce the
UN treaties. Such legislation can include the mitigation of space debris. Some launching States meet
their obligations by appointing non-regulatory government bodies, such as national space agencies, to
provide the necessary guidelines or requirements, including those for space debris mitigation.
The general aim of space debris mitigation is to reduce the growth of space debris by ensuring that
spacecraft and launch vehicle orbital stages are designed, operated and disposed of in a manner that
prevents them from generating debris throughout their orbit lifetime. Another aim of space debris
mitigation is to ensure that space objects re-entering the Earth’s atmosphere cause no harm. These
aims are achieved by the following actions:
a) avoiding the intentional release of space debris into Earth orbit during normal operations;
b) avoiding break-ups in Earth orbit;
c) removing spacecraft and launch vehicle orbital stages from protected orbital regions after the end
of mission;
d) performing the necessary actions to minimize the risk of collision with other space objects;
e) reducing the risks associated with re-entry, e.g. to people, property and the Earth's environment.
Such actions are especially important for a spacecraft or launch vehicle orbital stage that has one or
more of the following characteristics:
— has a large collision cross-section;
— remains in orbit for many years;
— operates near manned mission orbital regions;
— operates in highly utilized regions, such as protected regions;
— operates in regions of high debris population.
This document transforms these objectives into a set of high-level debris mitigation requirements.
Methods and processes to enable conformance with these requirements are provided in a series of
lower­level implementation standards.
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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 24113:2023(E)
Space systems — Space debris mitigation requirements
1 Scope
This document defines the primary space debris mitigation requirements applicable to all elements
of unmanned systems launched into, or passing through, near-Earth space, including launch vehicle
orbital stages, operating spacecraft and any objects released as part of normal operations.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
approving agent
entity from whom approval is sought for the implementation of space debris (3.23) mitigation
requirements with respect to the procurement of a spacecraft (3.25), or its launch, or its operations in
outer space, or its safe re-entry (3.22), or a combination of those activities
EXAMPLE Regulatory or licensing authorities; national or international space agencies; other delegated
organizations.
3.2
break-up
event that completely or partially destroys an object and generates space debris (3.23)
3.3
controlled re-entry
type of re-entry (3.22) where the time of re-entry is sufficiently controlled so that the impact of any
surviving debris on the surface of the Earth is confined to a designated area
Note 1 to entry: The designated area is usually an uninhabited region such as an ocean.
3.4
disposal
actions performed by a spacecraft (3.25) or launch vehicle orbital stage (3.13) to permanently reduce
its chance of accidental break-up (3.2) and to achieve its required long-term clearance of the protected
regions (3.21)
Note 1 to entry: Actions can include removing stored energy and performing post-mission orbital manoeuvres.
3.5
disposal manoeuvre
action of moving a spacecraft (3.25) or launch vehicle orbital stage (3.13) to a different orbit as part of its
disposal (3.4)
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ISO/FDIS 24113:2023(E)
3.6
disposal phase
interval between the end of mission (3.9) of a spacecraft (3.25) or launch vehicle orbital stage (3.13) and
its end of life (3.8)
3.7
Earth orbit
bound or unbound Keplerian orbit with Earth at a focal point, or Lagrange point orbit which includes
Earth as one of the two main bodies
3.8
end of life
instant when a spacecraft (3.25) or launch vehicle orbital stage (3.13)
a) is permanently turned off, nominally as it completes its disposal phase (3.6),
b) completes its manoeuvres to perform a controlled re-entry (3.3), or
c) can no longer be controlled by the operator
Note 1 to entry: See Annex A.
3.9
end of mission
instant when a spacecraft (3.25) or launch vehicle orbital stage (3.13)
a) completes the tasks or functions for which it has been designed, other than its disposal (3.4),
b) becomes incapable of accomplishing its mission (3.15), or
c) has its mission permanently halted through a voluntary decision
Note 1 to entry: See Annex A.
3.10
expected number of casualties per re-entry
DEPRECATED: re-entry casualty risk
number of people who are predicted to be killed or seriously injured by the re-entry (3.22) of a space
object (3.24)
Note 1 to entry: The medical profession has defined a number of different injury scoring systems to distinguish
the severity of an injury. Broadly, a serious injury is one of such severity that hospitalisation is required.
3.11
geostationary Earth orbit
GEO
Earth orbit (3.7) having zero inclination, zero eccentricity, and an orbital period equal to the Earth's
sidereal rotation period
3.12
launch vehicle
DEPRECATED: launcher
system designed to transport one or more payloads into outer space
3.13
launch vehicle orbital stage
complete element of a launch vehicle (3.12) that is designed to deliver a defined thrust during a dedicated
phase of the launch vehicle’s operation and achieve orbit
Note 1 to entry: Non-propulsive elements of a launch vehicle, such as jettisonable tanks, multiple payload
structures or dispensers, are considered to be part of a launch vehicle orbital stage while they are attached.
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ISO/FDIS 24113:2023(E)
3.14
launching State
State that launches or procures the launching of a spacecraft (3.25), or State from whose territory or
facility a spacecraft is launched
[5]
Note 1 to entry: This definition is consistent with the definition in the UN Liability Convention and the UN
[6]
General Assembly’s Resolution 59/115 on the notion of the launching State .
3.15
mission
set of tasks or functions to be accomplished by a spacecraft (3.25) or launch vehicle orbital stage (3.13),
other than its disposal (3.4)
3.16
mission lifetime extension
postponement of the previously defined end of mission (3.9)
3.17
normal operations
execution of the planned tasks or functions for which a spacecraft (3.25) or launch vehicle orbital stage
(3.13) was designed
Note 1 to entry: Normal operations include the disposal phase (3.6).
3.18
orbit lifetime
elapsed time between an orbiting space object’s (3.24) initial or reference position and its re-entry (3.22)
Note 1 to entry: Examples of "initial position" are the injection into orbit of a spacecraft (3.25) or launch vehicle
orbital stage (3.13), or the instant when space debris (3.23) is generated. An example of a "reference position" is
the orbit of a spacecraft or launch vehicle orbital stage at the end of mission (3.9).
3.19
passivate
act of permanently depleting, irreversibly deactivating, or making safe all
on-board sources of stored energy capable of causing an accidental break-up (3.2)
Note 1 to entry: Passivation is an effective measure for significantly reducing the chance of an accidental
explosion that can generate space debris (3.23).
Note 2 to entry: Propellant tanks, batteries, high-pressure vessels, self-destruct devices, flywheels and
momentum wheels are examples of on-board sources of stored energy capable of causing an accidental break-up.
It is preferable to passivate such items as soon as they are no longer required for mission operations or post-
mission disposal (3.4).
Note 3 to entry: A safe level of passivation is reached when any remaining stored energy cannot be expected to
cause an accidental break-up.
Note 4 to entry: In the event of a collision, a passivated space object (3.24) is likely to create fewer space debris
than a non-passivated space object.
3.20
probability of successful disposal
probability that a spacecraft (3.25) or launch vehicle orbital stage (3.13) is able to complete all of the
actions associated with its disposal (3.4)
Note 1 to entry: This probability is usually assessed before the launch of a spacecraft or launch vehicle orbital
stage. It can also be reassessed after launch taking into consideration any changes in the operational status
of hardware. This is particularly important when deciding whether to extend the mission (3.15) lifetime or
postpone the end of life (3.8).
Note 2 to entry: The assessment of this probability includes consideration of uncertainties in the availability of
resources, such as propellant, required for the disposal.
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ISO/FDIS 24113:2023(E)
Note 3 to entry: The assessment of this probability can include consideration of the inherent reliability of
equipment that is necessary to conduct the disposal, monitoring of the equipment, and operational remediation
of any observed degradation or failure of the equipment.
3.21
protected region
region in outer space that is protected with regard to the generation of space debris (3.23) to ensure its
safe and sustainable use in the future
3.22
re-entry
permanent return of a space object (3.24) into the Earth’s atmosphere
Note 1 to entry: Several alternative definitions are available for the delineation of a boundary between the
Earth’s atmosphere and outer space.
3.23
space debris
DEPRECATED: orbital debris
objects of human origin in Earth orbit (3.7) or re­entering the atmosphere, including fragments and
elements thereof, that no longer serve a useful purpose
Note 1 to entry: Spacecraft (3.25) in reserve or standby modes awaiting possible reactivation are considered to
serve a useful purpose.
3.24
space object
object of human origin which has reached outer space
3.25
spacecraft
system designed to perform a set of tasks or functions in outer space, excluding launch vehicle (3.12)
4 Symbols and abbreviated terms
4.1 Symbols
2 −1
A/m aspect area to dry mass ratio (m kg )
C solar radiation pressure coefficient (0 < C < 2)
R R
Z altitude measured with respect to a spherical Earth whose radius is 6 378 km
Z altitude of the geostationary Earth orbit with respect to a spherical Earth whose radius is 6 378 km
GEO
ΔH change in altitude (km)
4.2 Abbreviated terms
GEO geostationary Earth orbit
LEO low Earth orbit
LV launch vehicle
S/C spacecraft
SDMP space debris mitigation plan
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ISO/FDIS 24113:2023(E)
5 General
The requirements contained in this document are intended to reduce the growth of space debris by
ensuring that spacecraft and launch vehicle orbital stages are designed, operated and disposed of in a
manner that restricts them from generating debris throughout their orbit lifetime. The requirements
are also intended to reduce the casualty risk on ground associated with atmospheric re-entry of space
objects.
This document is the top-level standard in a family of standards addressing space debris mitigation.
It is the main interface for the user, bridging between the primary space debris mitigation objectives
and a set of lower level standards and technical reports that support conformance. The lower­level
documents contain detailed requirements and implementation measures associated with the high-level
requirements in this document.
6 Protected regions
6.1 General
The requirements in this document are concerned with limiting the production of space debris in Earth
orbit. Particular emphasis is placed on the LEO and GEO regions, which are considered as protected
regions with regard to the generation of space debris (see Figure 1). This is necessary to ensure their
safe and sustainable use in the future.
Key
1 Earth
2 equatorial plane
3 GEO protected region
4 LEO protected region
NOTE The dimensions in the figure are not to scale.
Figure 1 — Three-dimensional view of the protected regions around the Earth
The requirements in this document do not apply to a space object that enters an unbound Keplerian
orbit or leaves Earth orbit, provided that for at least 100 years after doing so:
a) the space object does not cross the protected regions;
b) the expected number of casualties from the space object’s re-entry is assessed to be less than the
threshold set in 7.3.4.3.
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ISO/FDIS 24113:2023(E)
6.2 LEO protected region
[2]
The LEO protected region, as defined by the IADC and illustrated in Figure 1, is a complete spherical
shell that extends from the surface of a spherical Earth with an equatorial radius of 6 378 km up to an
altitude, Z, of 2 000 km.
6.3 GEO protected region
[2]
The GEO protected region, as defined by the IADC and illustrated in Figure 1, is a segment of a
spherical shell with the following characteristics:
a) lower altitude: geostationary altitude minus 200 km;
b) upper altitude: geostationary altitude plus 200 km;
c) latitude sector: 15° south ≤ latitude ≤ 15° north,
where geostationary altitude (Z ) is approximately 35 786 km, i.e. the altitude of the geostationary
GEO
Earth orbit above a spherical Earth with an equatorial radius of 6 378 km.
7 Technical requirements
7.1 Restricting the intentional release of space debris into Earth orbit during normal
operations
7.1.1 General
7.1.1.1 Spacecraft shall be designed so as not to release space debris into Earth orbit during normal
operations, other than space debris from pyrotechnics and solid rocket motors.
7.1.1.2 The total number of launch vehicle orbital stages and space debris objects left in Earth orbit
by a launch vehicle during normal operations, other than space debris from pyrotechnics and solid
rocket motors, shall be limited to one for the launch of a single spacecraft and two for the launch of
multiple spacecraft.
7.1.1.3 Space debris left in Earth orbit by a launch vehicle after normal operations, other than space
debris from pyrotechnics and solid rocket motors, shall satisfy the followin
...