ISO/TR 20590:2021

TECHNICAL ISO/TR
REPORT 20590
Second edition
2021-04
Space systems — Space debris
mitigation design and operation
manual for launch vehicle orbital
stages
Systèmes spatiaux — Lignes directrices de conception et de
manœuvre des étages orbitaux de lanceurs pour réduire les débris
spatiaux
Reference number
©
ISO 2021
© ISO 2021
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ii © ISO 2021 – All rights reserved

Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 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
5.2.1 Intents of requirements in ISO 24113 . 3
5.2.2 Work breakdown . 3
5.2.3 Identification of released objects and design measures . 4
5.2.4 Monitoring during operation . 5
5.2.5 Preventing failure . 5
5.3 Break-up prevention . 5
5.3.1 Break-up caused by intentional behaviour, or stored energy . 5
5.3.2 Avoidance of collision . 7
5.4 Disposal manoeuvres at the end of operation . 7
5.4.1 Intents of requirements in ISO 24113 . 7
5.4.2 Work breakdown . 8
5.4.3 LEO mission . 8
5.4.4 GEO missions and other high-elliptical orbit missions . 9
5.5 Ground safety from re-entering objects .10
5.5.1 Intents of requirements in ISO 24113 .10
5.5.2 Work breakdown .10
5.5.3 Preventive measures .11
5.5.4 Risk detection: notification .13
5.5.5 Countermeasures: controlled re-entry and monitoring .13
5.6 Reliability and QA .13
6 Debris-related work in the development life cycle .13
6.1 General .13
6.2 Concept of debris-related work in each phase .13
6.3 Mission requirements analysis phase (pre-phase A) .18
6.3.1 General.18
6.3.2 Debris-related works .18
6.4 Feasibility phase (phase A) .18
6.5 Definition phase (phase B) .18
6.5.1 Work in phase B .18
6.5.2 Work procedure .19
6.6 Development phase (phase C) .19
6.7 Production phase (phase D) .20
6.7.1 Work in phase D .20
6.7.2 Qualification review .20
6.7.3 Launch service .20
6.8 Utilization phase (phase E) .20
6.9 Disposal phase (phase F) .20
7 System-level information.21
7.1 System design.21
7.2 Mission analysis for each launch mission .21
8 Subsystem/Component design and operation .22
8.1 General .22
8.1.1 Scope .22
8.1.2 Debris-mitigation measures and subsystem-level actions for realizing them .22
8.2 Propulsion subsystem .23
8.2.1 Debris-related design .23
8.2.2 Information of propulsion subsystems .23
8.2.3 Information of component design .25
8.3 Guidance and control subsystem .26
8.3.1 Debris-related designs .26
8.3.2 Information of the guidance and control subsystem .27
8.4 Electric power-supply subsystem .27
8.4.1 Debris related design .27
8.4.2 Information of power subsystems .27
8.4.3 Information of component design .28
8.5 Communication subsystem .28
8.5.1 Debris-related designs .28
8.5.2 Design of communication subsystem .28
8.5.3 Information of component design .29
8.6 Structure subsystem .29
8.6.1 Design measures .29
8.6.2 Practices for structure subsystem .29
8.6.3 Information of component design .30
8.7 Range safety subsystem (self-destruct subsystem) .30
8.7.1 Debris-related designs .30
8.7.2 Information of command destruction subsystem .30
8.7.3 Information of component design .30
Bibliography .31
iv © ISO 2021 – 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 first edition (ISO/TR 20590:2017), which has been
technically revised.
The main changes compared to the previous edition are as follows:
— text has been updated to be aligned with ISO 24113:2019;
— information has been added that the total number of structural elements and orbital stages is
limited according to the number of payloads;
— 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;
— 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 can also be taken to ensure the safety of those on
the ground from re-entering objects that were disposed of from Earth orbit.
Recently, the orbital environment has become so deteriorated by debris that it is necessary to take
actions to mitigate the generation of orbital debris in design and operation of both spacecraft and the
launch vehicle orbital stages.
ISO 24113 and other ISO documents, introduced in Bibliography, were developed to encourage debris
mitigation activities.
In Clause 5, information about the major space debris mitigation requirements is provided.
In Clause 6, information about 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 the requirements and recommendations from
ISO documents for the design and operation of the launch vehicles.
vi © ISO 2021 – All rights reserved

TECHNICAL REPORT ISO/TR 20590:2021(E)
Space systems — Space debris mitigation design and
operation manual for launch vehicle orbital stages
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 the requirements and recommendations in the
space debris mitigation standards to reduce the growth of space debris by ensuring that launch vehicle
orbital stages are designed, operated, and disposed of in a manner that prevents them from generating
debris throughout their orbital lifetime.
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 24113:2019, Space systems — Space debris mitigation requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 24113 apply.
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
CDR critical design review
CNES Centre National d'Études Spatiales
COPUOS Committee on the Peaceful Uses of Outer Space
CSpOC Combined Space Operations Center (USA)
DAS debris assessment software (NASA)
DRAMA debris risk assessment and mitigation analysis (ESA)
E expected number of casualties
c
EOMDP end-of-mission (operation) disposal plan
EOL end-of-life
ESA European Space Agency
FDIR failure detection, isolation and recovery
FMEA failure mode and effect analysis
GEO geostationary Earth orbit
GTO geosynchronous transfer orbit
IADC Inter-Agency Space Debris Coordination Committee
JAXA Japan Aerospace Exploration Agency
LEO low Earth orbit
LV launch vehicle
NOTAM notice to airmen and notice to mariners
NM notice to mariners
PDR preliminary design review
QA quality assurance
QR qualification review
S/C spacecraft
SDMP space-debris-mitigation plan
SRR system requirement definition review
STELA semi-analytic tool for end of life analysis (CNES)
UN United Nations
5 System-level activities
5.1 General
To accomplish comprehensive activities for debris mitigation work, the following steps are considered:
a) Identifying debris related requirements, recommendations, and best practices.
b) Determining how to comply with requirements, recommendations, and best practices.
c) Applying debris mitigation measures early and throughout development and manufacturing to
assure sound debris mitigation capability in the final product.
d) Applying appropriate QA and qualification programs to ensure compliance with debris mitigation
requirements.
e) Applying appropriate procedures during operation/utilisation and disposal to implement proper
space debris mitigation.
This clause provides information useful for taking comprehensive action at the system level. More
detailed information for action at the subsystem and component levels is provided in Clause 8. The
following specific subjects are emphasized:
— limiting the release of objects into the Earth orbit;
2 © ISO 2021 – All rights reserved

— preventing fragmentation in orbit;
— proper disposal at the end of operation;
— minimization of hazards on the ground from re-entering debris;
— collision avoidance during launch at least for inhabited systems;
— quality, safety, and reliability assurance.
5.2 Design for limiting the release of objects
5.2.1 Intents of requirements in ISO 24113
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 (larger than 1 mm) from
pyrotechnics, slag (larger than 1 mm) from solid rocket motors, etc.
The following objects are concerned:
a) objects released according to the mission requirements (not directly indicated in ISO 24113:2019,
6.1.1.1, though);
b) mission-related objects, such as yo-yo de-spinners, fasteners and other parts (ISO 24113:2019,
6.1.1.1);
c) total number of structural elements in multi-payloads launches and orbital stages. (ISO 24113:2019,
6.1.1.2);
d) fragments and combustion products from pyrotechnic devices (ISO 24113:2019, 6.1.2.1);
e) slag from solid motors (ISO 24113:2019, 6.1.2.2).
ISO 24113 implies that if objects are unavoidably released despite the requirements, the orbital lifetime
of such objects in LEO and the interference with GEO is limited as described in ISO 24113:2019, 6.1.1.3
(a typical example is the support structure utilized in a multiple payloads mission).
5.2.2 Work breakdown
Table 1 shows the work breakdown as delineated in ISO 24113 to prevent the release of debris.
Table 1 — Work breakdown for preventing the release of debris
Process Subjects Major work
Preventive measures Identification of re- a) Take preventive design to avoid releasing objects that would turn
leased objects and into space debris.
design measures
b) Minimise the total number of structural elements in multi-
payloads launches, orbital stages, etc.
c) If release is unavoidable, designers estimate the orbital lifetime
of released objects and check compliance with ISO 24113:2019,
6.1.1.3.
d) Apply pyrotechnic device which doesn’t eject fragments or
combustion product.
e) When applying the solid motors, the possibility of generation of
slag and its risk posed to environment will be assessed.
Table 1 (continued)
Process Subjects Major work
Corrective actions Trouble shooting Reference: If an object would be released unexpectedly, it is investi-
gated and taken appropriate action to avoid repeating the release in
the following missions.
5.2.3 Identification of released objects and design measures
a) Mission-related objects
The following objects are concerned (ISO 24113:2019, 6.1.1.1):
1) nozzle closures for propulsion devices and certain types of igniters for solid motors, which are
ejected into space after ignition (particularly if their orbital lifetimes are longer than 25 years);
2) clamp bands that tie the S/C and launch vehicles;
3) structural elements used in multi-payloads launches, fragments and combustion products from
pyrotechnic devices, and slag from solid motors are excluded from ISO24113: 2019, 6.1.1.1, but
are mentioned in ISO24113: 2019, 6.1.1.2 and 6.1.2.
b) Structural elements in multi-payloads launches, orbital stages, etc. (ISO 24113:2019, 6.1.1.2)
ISO 24113:2019, 6.1.1.2 requires limiting the total number of orbital stages and “space objects” to
one for the launch of a single spacecraft and two for the launch of multiple spacecraft. Generally,
“space objects” means structural elements such as payload adaptors.
This requirement seems to prohibit to inject multiple stages in any instance. However, considering
the ultimate objective to minimize the number and mass of orbital objects, this requirement can
be understood in a slightly different way. For example, in the case that a three-stage LV is designed
to leave two stages in orbit during the launch of a single spacecraft, if the second stage has a very
short decay life, the third stage is relatively small, and that the total in-orbit collision risk and the
total re-entry casualty risk are demonstrably lower compared to the option of leaving one stage
in orbit, it is an option worth studying. Careful analysis is needed to confirm the benefit before
applying this requirement.
c) Fragments and combustion products from pyrotechnic devices (ISO 24113:2019, 6.1.2.1)
Adequately designed devices are selected to avoid the release of fragments or combustion products.
It is possible to apply parts that trap all fragments and combustion products larger than 1 mm
inside for segregation.
d) Combustion products from solid motors (ISO 24113:2019, 6.1.2.1)
1) It is preferable not to use an upper-stage with solid propulsion potentially leaving debris
in orbit (slag, throat elements), especially if the altitude of the orbit is higher than that of
inhabited systems, and if the solid propulsion system conception includes a dead-zone where
recirculating gases can concentrate some metalized slag which can be ejected in orbit.
2) It is taken into consideration that if a solid motor is fired to decrease the velocity of the orbital
object, to deorbit it for instance, as the particles velocity would increase with that of the orbital
object, leading to an increase in apogee of the particles.
e) Estimation of orbital lifetime (ISO 24113:2019, 6.1.1.3)
The orbital lifetime of released objects is assessed as specified in ISO 27852. ISO 27852 designates
acceptable analysis methodologies the user employs dependent upon the orbit regime. The available
simplified tools that are admissible to estimate the long-term orbital lifetime are introduced in
5.4.3.1.
4 © ISO 2021 – All rights reserved

5.2.4 Monitoring during operation
The released objects, if they are large enough to be detected from the ground, can be confirmed by
ground-based space tracking facilities to ensure that they are released as expected and that their
orbital lifetimes are sufficiently short. The Space Situation Report provided by the US Combined Space
Operations Center (CSpOC https:// www .space -track .org/ auth/ login) provides a good reference.
5.2.5 Preventing failure
If objects are released unexpectedly, the origin of the objects can be identified to help prevent
recurrence in future missions. Because such phenomena can indicate a malfunction, the situation is
reviewed carefully, and appropriate action is taken to prevent further abnormal conditions.
5.3 Break-up prevention
5.3.1 Break-up caused by intentional behaviour, or stored energy
5.3.1.1 Intents of requirements in ISO 24113
ISO 24113:2019, 6.2 requires the prevention of break-ups caused by intentional behaviour, stored
energy, collision with large objects, and impact of tiny debris or meteoroid. This subclause introduces
the result of study for the break-ups due to the intentional behaviour, and the stored energy.
While ISO 16127 addresses the prevention of break-ups of S/C, it also provides useful information to the
launch vehicle.
5.3.1.2 Work breakdown
Table 2 shows the work breakdown as delineated in ISO 24113 to prevent orbital break-up.
Table 2 — Work breakdown for preventing orbital break-ups
Process Subjects Major work
Preventive measures Identification of Identify components that can cause fragmentation during or
sources of breakup after operation.
Design measures 1) Preventive designs to limit the probability of accidental
−3
break-up during operation no greater than 10 . Confirm it
with FMEA.
2) Providing functions to prevent break-ups after disposal.
3) Preventive design to avoid an unintentional destruction of
a self-destruct system caused by miss-command or solar
heating.
Risk detection Monitoring for 1) Providing functions to monitor the health of vehicle at the
successful disposal critical events particularly for the decision to proceed to the
controlled re-entry.
2) In the case of controlled re-entry, the critical parameters to
decide the initiation of re-entry action are monitored.
3) All the cases including the non-controlled re-entry, some
parameters to identify the successful execution of critical
operation, such as re-ignition, separation of payload,
passivation, etc. are being monitored.
Actions in operation Preventive measures Energy sources for break-up are removed (residual propellants,
phase for break-up high-pressure gas, etc.) or designed to assure safety so as not to
cause break-ups after the end of operation.
5.3.1.3 Identification of the sources of break-up
The following launch vehicle subsystem or elements can be potential causes of break-ups:
a) propulsion subsystems and associated components (rocket engines and solid motors, tanks, tank
pressurizing systems, valves, piping, etc.);
b) electrical batteries;
c) pressure vessels and other equipment (such as pneumatic control systems);
d) self-destruct systems for range safety.
5.3.1.4 Design measures
Nowadays, the following aspects are incorporated into the design of launch vehicles.
a) Avoiding accidental break-ups during operation
−3
Per ISO 24113, the probability of accidental break-up is no greater than 10 until its EOL.
ISO 16127 is designed to apply to the S/C, but ISO 16127:2014, Annex A provides adequate
instructions to engineers on coping with complicated subsystems such as liquid rocket engines.
To prevent the unintentional explosion of self-destruct charges, the command destruct receivers
are turned off after passing through the range safety areas to prevent explosion due to miss-
command.
b) Preventing break-ups that occur after the end of operation
The following items are the typical measures to prevent fragmentation for each of the items
identified in 5.3.1.3. More detailed information for each subsystem or component is described in
Clause 8.
1) Residual propellants in the propulsion systems and associated components
— burning residual propellants to depletion;
— venting residual propellant until its amount is insufficient to cause a break-up by ignition
or pressure increase from tanks and lines;
— adequate design of tank. (Historically, some explosion events of the orbital stages and the
assist modules were caused by a type of propellant tank design combined fuel and oxygen
tanks, separating them only by a common bulkhead.)
2) High pressure fluids
— venting pressurized systems.
3) Range safety systems
— prevention from inadvertent commands, thermal heating, or radio frequency interference.
5.3.1.5 Preventive measures for break-up after mission completion
After separation of payloads, the major sources of break-ups (examples listed in 5.3.1.3) are mitigated
(vented or operated in safe mode) according to ISO 16127:2014, 4.4.
Residual propellants and other fluids, such as pressure gasses, are depleted as thoroughly as possible,
by either depletion burns or venting, to prevent accidental breakups by over pressurization or chemical
reaction. Opening fluid vessels and lines to the space environment, directly or indirectly, at the
conclusion of EOM passivation, is one way to reduce the possibility of a later explosion or rupturing,
6 © ISO 2021 – All rights reserved

especially if the stage thermal configuration and solar aspect angle allow for a vaporisation of the
remaining propellant.
The passivation actions are usually monitored to confirm the successful disposal.
5.3.2 Avoidance of collision
There are no definite requirements for collision avoidance of the launch vehicles in ISO 24113. However,
[3]
the UNCOPUOS Space Debris Mitigation Guidelines address that "the probability of accidental
collision with known objects during the systems’ launch phase and orbital lifetime should be estimated
and limited. And if available orbital data indicate a potential collision, adjustment of the launch time or
an orbital avoidance manoeuvre should be considered".
For the launch vehicle, the only way to avoid collision is to coordinate the lift-off time so as not to collide
with known objects and ensure no collisions until a space surveillance network, e.g. CSpOC, determines
the orbital characteristics of orbital stages and other released objects.
However, since the dispersion of flight trajectories complicates the avoidance of collision with all
known objects at later times, the best practice is at least to avoid collision with inhabited systems
whose operational plan is disclosed (ISS, etc.), primarily for safety reasons. When it is obvious that lift-
off times or flight trajectories conflict with known objects, it is desirable to avoid these lift-off times or
flight trajectories.
The criteria and procedures for collision avoidance have not been globally defined yet. The basic
concept is that a launch service provider assures that each stage of the launch vehicle, payload, and
other objects separated from the stages would not collide for a few days (two days, for example) after
lift-off until a space surveillance network, e.g. CSpOC, determines the orbital characteristics of orbital
stages and all the objects separated from them.
5.4 Disposal manoeuvres at the end of operation
5.4.1 Intents of requirements in ISO 24113
ISO 24113:2019, 6.3 addresses the disposal of a spacecraft or launch vehicle orbital stage at end-of-
mission and requires that probability of successful disposal (PSD) be larger than 0,9. This requirement
is based on the research conducted by IADC that, to keep the LEO environment stable, LEO space system
is removed from the LEO protected orbital region within 25 years, on the condition that the 90 % of the
space systems are disposed properly.
The probability is evaluated based on mainly the inherent reliabilities of disposal function. However,
since such probability is dependent on several other factors which are identified in ISO 24113, and some
of them are unmeasurable factors, there is no method to demonstrate perfectly the compliance with
this requirement quantitively. These factors are:
a) the uncertainties in the availability of resources, such as propellant;
b) the inherent reliabilities of subsystems, monitoring of those subsystems, and operational
remediation of any observed subsystem degradation or failure;
c) the risk that a space debris or meteoroid impact prevent the disposal (not mandatory).
In the case of spacecraft, the compliance is assessed with comprehensive design and operation measures
and procedures. In the case of the launch vehicle, the reliability at the end of mission is assessed with a
normal procedure; and the resources for disposal maneuverer is assured. The matters of the probability
of impact with debris and meteoroid, or the effect of life extension, are not concerned.
ISO 26872 provides more detailed requirements and procedures for the disposal of GEO missions (the
mission of direct injection of GES) to comply with the high-level requirements stated in ISO 24113;
and ISO 16699 provides more detailed requirements and procedures for the disposal of launch vehicle
orbital stages in LEO missions.
5.4.2 Work breakdown
Table 3 shows the work breakdown as delineated in ISO 24113 to protect orbital regions.
Table 3 — Work breakdown for the preservation of the LEO-protected region
Process Subjects Major work
Preventive Estimate the orbital Estimate the orbital lifetime after payload separation and define a
measures lifetime and define a disposal manoeuvre plan.
disposal plan
Disposal planning One of the following methods is applied. (ISO 24113:2019, 6.3.3.2):
a) retrieving it safely to Earth, as per ISO 24113:2019, 6.3.3.2, a), or
b) performing a controlled re-entry with a well-defined impact
footprint on the surface of the Earth, or
c) allowing its orbit to decay naturally in accordance with the
specified 25-year limit for orbit lifetime, or
d) manoeuvring it to reduce the remaining time to comply with the
specified 25-year limit, or
e) augmenting its orbital decay by deploying a device to reduce the
remaining time to comply with the specified 25-year limit.
The option to manoeuvre a perigee altitude to above the LEO
protected region was deleted in ISO 24113:2019.
Disposal function Functions and resources are provided to remove orbital stages (e.g.
and resources restart function of main engine, secondary propulsion systems, or
independent thrusters) from the protected orbital region.
Reliability of disposal Design the reliability of disposal function in development life cycle
function or confirm it in the production life cycle.
Action in opera- Disposal sequence Disposal operations are executed in the proper sequence.
tion phase
5.4.3 LEO mission
5.4.3.1 Estimate the orbital lifetime and define a disposal plan
For LEO missions, ISO 16699:2015, 5.3 shows the planning and documentation for a disposal manoeuvre.
ISO 27852 shows the steps and tools to estimate the orbital lifetime in more detail. The precision of
analysis is dependent on the algorithm; and using high-precision algorithms, it takes several hours to
complete the analysis, which is not adequate for use in the early phases when the exact operation plan
has not been fixed. Tools are selected during the design phase.
There are several tools available to calculate the orbital lifetime, for instance:
a) ISO 27852 introduces “STELA” available via the CNES freeware server. As of October 2020, the latest
version is 3.3, and it can be downloaded from https:// logiciels .cnes .fr/ content/ stela ?language = en.
NASA is releasing “DAS (debris assessment software)” (since October 2020, latest version is v 3.0.1),
which has functions to analyse various debris related matters comprehensively, including the orbital
lifetime analysis (https:// orbitaldebris .jsc .nasa .gov/ mitigation/ debris -assessment -software .html).
b) ESA provides the DRAMA tool available at https:// sdup .esoc .esa .int/ .
c) Other viable commercial off-the-shelf (COTS) toolkits exist to determine orbit lifetime.
8 © ISO 2021 – All rights reserved

5.4.3.2 Disposal planning
ISO 16699 provides more detailed requirements and guidance for the orbital stages. An EOMDP is
required. The process of developing it is described in detail in ISO 16699:2015, Clause 7.
5.4.3.3 Disposal function and resources to transition to disposal orbit
a) It is thought to be better to provide liquid propellant engines with a re-start function to perform a
disposal manoeuvre after payload separation.
b) In some cases, other propulsion devices, including attitude control thrusters, can be used.
c) Drag-enhancement, solar radiation pressure, or other devices can also be used.
5.4.3.4 Probability of successful disposal
In the case of S/C, since it is not easy to comply with requirement of the probability, ISO 24113:2019,
3.20, Note 2 to entry states: “The calculation of this probability can include the inherent reliabilities of
subsystems that are necessary to conduct the disposal, monitoring of those subsystems, and operational
remediation of any observed subsystem degradation or failure”. However, in the case of launch vehicle,
achieving compliance is usually considered easier, since the mission duration is so short that there is
no need to be conscious about the degradation of reliability, limit of the useful lifetime, degradation of
components, probability of debris impact, etc.
ISO 24113:2019, 6.3.1.3 requires spacecraft to decide on initiating the disposal action in adequate
conditions to assure a successful disposal. However, for the launch vehicle orbital stage, it is applied to
just the case of controlled re-entry and requires developing a specific criterion to allow initiating the
re-entry operation and if met, consequent actions are executed. This requirement intends to minimize
the re-entry risk due to the unsuccessful controlled re-entry.
NOTE ISO 24113:2019, 6.3.1.3 supports an on-board Go/NoGo criterion and computation to determine
whether a controlled re-entry is to be pursued or not, in real time. This criterion considers the status of on-board
avionics, remaining propellant, etc.
5.4.4 GEO missions and other high-elliptical orbit missions
5.4.4.1 General
Detailed requirements and procedures for GEO S/C are defined in ISO 26872. The concept of disposal
methods of launch vehicle orbital stages for the mission of direct injection of GES, is similar to those for
the GEO S/C.
There are several methods to launch a GEO S/C; and the typical methods are the following:
a) High elliptical GTO: this is the most typical case in which the perigee altitude is within or close to
the LEO protected region, and the apogee altitude is near GEO. The S/C is transferred to GEO by
firing its apogee kick propulsion system.
b) Direct injection: the orbital stages reach the circular orbit near GEO. The S/C is transferred to GEO
with the S/C control function.
c) Another elliptical orbit: the apogee altitude is higher than GEO; and the perigee altitude is inside or
near the LEO protected region.
5.4.4.2 High elliptical GTO
In the case of the high elliptical GTO mentioned in 5.4.4.1, a), orbital stages left in GTO after payload
injection generally pose a risk to both GEO and LEO protected regions.
It is desir
...