General
JMR-016(E)Standard for Spacecraft Collision Risk Management

December 27, 2022

Japan Aerospace Exploration Agency

This is an English translation of JMR-016 and does not constitute itself.
Whenever this document conflicts with the original document in Japanese, theoriginal document takes precedence.
Disclaimer
The information contained herein is for general informational purposes only. JAXA
makes no warranty, express or implied, including as to the accuracy, usefulness ortimeliness of any information herein. JAXA will not be liable for any losses relating
to the use of the information.

JMR-016(E)

Table of contents
1.

General .......................................................................................................................... 3
1.1.

Purpose .................................................................................................................... 3

1.2.

Background ............................................................................................................. 3

1.3.

Application .............................................................................................................. 4

1.3.1.
2.

3.

4.

5.

Related documents......................................................................................................... 4
2.1.

Compliant documents ............................................................................................ 4

2.2.

Applicable documents ............................................................................................ 5

2.3.

Reference documents.............................................................................................. 5

Definitions ...................................................................................................................... 5
3.1.

Definition of terms.................................................................................................. 5

3.2.

Definition of abbreviations .................................................................................... 6

A basic approach to conjunction assessment and collision avoidance operation ...... 6
4.1.

Requirements for development phase ................................................................... 6

4.2.

Requirements for operation phase ........................................................................ 7

General requirements ................................................................................................... 7
5.1.

6.

Tailoring ....................................................................................................... 4

Basic requirements................................................................................................. 7

5.1.1.

Collision avoidance management ............................................................... 8

5.1.1.1.

Overview ...................................................................................................... 8

5.1.1.2.

Organizations in charge .............................................................................. 8

5.1.1.3.

Collision avoidance management plan ...................................................... 9

5.1.2.

Requirements for the COLA team .............................................................. 9

5.1.3.

Requirements for the CA team ................................................................. 10

5.1.4.

Requirements for the CMO....................................................................... 10

Detailed requirements ................................................................................................. 10
6.1.

Basic requirements............................................................................................... 10

6.2.

Collision risk assessment..................................................................................... 10

6.2.1.

Collision risk assessment indicators ........................................................ 10

6.2.2.

Collision risk level ......................................................................................11

6.2.2.1.

Level 1 (MONITOR) ...................................................................................11

6.2.2.2.

Level 2 (URGENT) .....................................................................................11

6.2.2.3.

Level 3 (CRITICAL) .................................................................................. 13

6.2.3.

Collision risk level transitions .................................................................. 13

6.3.

Actions according to the collision risk level........................................................ 141

JMR-016(E)7.

6.3.1.

Primary object with maneuver capability ............................................... 15

6.3.2.

Primary object without maneuver capability .......................................... 18

Contact for inquiries .................................................................................................... 20

ANNEX A. Effectiveness of collision risk assessment using a probability of collision 21
ANNEX B. Comparison with collision avoidance criteria of other space agencies...... 222

JMR-016(E)1.

General

1.1.

PurposeThe purpose of this standard is to avoid collisions between satellites owned by the Japan
Aerospace Exploration Agency (hereinafter referred to as "JAXA") and other space
objects. This standard specifies requirements for operations to be performed by theoperation organization responsible for collision avoidance operations (hereinafterreferred to as the "Organizations in charge"). This standard specifies only general
requirements independent of satellites specification.
1.2.

Background

This section presents the background of the establishment of this standard.
Since the Soviet Union launched Sputnik 1 in 1957, artificial satellites began to exist inorbit. Satellites and rocket bodies that have completed their missions remain in orbit forlong periods and are recognized as one of the main obstacles to sustainable spacedevelopment in the future. When centimeter-sized space debris collides with a primaryobject, the primary object is partially or destroyed, and even millimeter-sized spacedebris has the power to shut down an operational satellite if it collides with a criticalpoint for satellite operation. Such collisions have occurred and have been summarized
by NASA (Reference Document (12)).
To prevent collision accidents, each space agency conducts conjunction assessment andcollision avoidance operations. NASA has established a handbook (Reference Document(1)) that defines best practices for conjunction assessment and collision avoidance, whichis available to the public.
To protect the primary object from secondary objects that may collide with the primaryobject, the Space Tracking and Communication Center (STCC) in JAXA provides support
for Conjunction Assessment and Collision Avoidance operations. The STCC hasdeveloped management guidelines for space debris collision risk (hereinafter referred toas "the STCC Management Guidelines"). Since FY 2017, the STCC has been conducting
conjunction assessment and collision avoidance operational support using a probabilityof collision as an indicator of collision risk based on the STCC Management guidelines
and has confirmed the effectiveness of the guidelines.
On the other hand, in 2019, the United Nations Committee on the Peaceful Uses of Outer
Space adopted the "Guidelines for the Long-Term Sustainability of Outer Space(hereinafter referred to as "LTS Guidelines"). Compliance Document (1)" was adopted.
JAXA needs to demonstrate its implementation of "B.4 Perform conjunction assessment
during all orbital phases of controlled flight" of the 21 items adopted in the LTS
3

JMR-016(E)Guidelines, and appropriate collision risk management. The risk of collision with anobject on a JAXA-owned satellite, if manifested, could have a serious impact on JAXA
and could develop into a crisis requiring an agency-wide response. Based on the need to
stipulate standard requirements to be implemented by the organizations involved in onorbit operations for the management of collision risk for satellites owned by JAXA, andthe effectiveness of the STCC management guidelines, a general standard for primaryobjects will be established as a JAXA standard.

1.3.

Application

For satellites developed by JAXA and operated in Earth orbit, this standard shall becalled out and applied to development and operation documents, etc., to manage the riskof collision during operations from the time when the orbital accuracy required forscreening is confirmed after separation from the launch vehicle until the satellite is
terminated. In addition, this standard shall be applied to the counterparty of the contract,etc., as necessary.
1.3.1. Tailoring
The requirements of this standard may be applied by selecting and modifying therequirements in consideration of various conditions, such as the characteristics andproperties of the primary object and the information handled in the primary object.
If necessary, the organization responsible for conducting conjunction assessment andcollision avoidance operations (see Section 5.1.1.2) may tailor the requirements byconsulting with the JAXA Safety and Mission Assurance Department, describing themin a collision avoidance operation management plan, and obtaining approval from the
JAXA Safety Review Board.
2.

Related documents

2.1.

Compliant documents

The existing codes and standards upon which this standard is based are as follows.
(1) Committee on the Peaceful Uses of Outer Space, Guidelines for the Long-term

Sustainability of Outer Space Activities, 27 June 2018.
(2) Regulations about space debris information management (Decision No. 16-1 by the
Director of the Tracking and Network Technology Center)(3) JMR-011, Risk Management Handbook

4

JMR-016(E)2.2.

Applicable documents

The following documents are applicable to this standard and form part of this standard.
In principle, the latest version should be applied.
(1) JERG-2-026, Safety Standards for On-orbit Service Missions(2) AAX-03014, Crisis Management Office Operations Manual
2.3.

Reference documents

The reference documents for this standard are as follows.
(1) NASA, NASA Spacecraft Conjunction Assessment and Collision Avoidance Best
Practices Handbook, December 2020.
(2) QNX-160020, Management Procedure for Space Debris Impact Risk (supplemental
manual)(3) QNX-160019, Management Procedure for Space Debris Impact Risk (main text)(4) QNX-160021, Probability of collision used to calculate space debris collision risk
(5) JJX-2011023, Information communication response for debris avoidance maneuvers,etc.
(6) François LaPorte, “Operational Management of Collision Risks for LEO Satellites
at CNES”, Space Operations Communicator, Vol. 5, No. 4, 2008.
(7) J. Beaumet, "CNES operational feedbacks in collision avoidance for LEO satellites",
ISSFD 2009.
(8) T. Flohrer, V. Braun, H. Krag, K. Merz, S. Lemmens, B. Bastida Virgili, and Q. Funke,“Operational Collision Avoidance at ESOC”, Deutscher Luft- und Raumfahrtkongress 2015.
(9) H. Krag, K. Merz, T. Flohrer, S. Lemmens, B. Bastida Virgili, Q. Funke and V. Braum,“ESA’s Modernised Collision Avoidance Service”, SpaceOps 2016.
(10) The Consultative Committee for Space Data Systems, Conjunction Data Message(Blue Book).
(11) JERG-1-011, Basic Requirements for Flight Safety of Satellite Launch Vehicles(12) NASA, History of On-Orbit Satellite Fragmentations, 15th edition, July 2018.
3.

Definitions

3.1.

Definition of terms

The definitions of terms used in this standard are as follows.
(1) Collision avoidance maneuver
A trajectory maneuver to avoid secondary objects that are at risk of collision.
(2) Collision avoidance operations
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JMR-016(E)The sequence of operations from transition to Collision Risk Level 1 to release of
Collision Risk Level 2 or 3.
(3) Probability of collision
Probability of collision between primary and secondary objects used to evaluate
collision risk.
(4) Conjunction Assessment
To identify secondary objects approaching the primary object by comparing orbital
calendars, etc., and to quantify the risk of collision between them.
(5) Earth orbit
Orbit with the earth as the central celestial body.
(6) Final decision meeting
A meeting to determine whether to execute collision avoidance maneuvers.
(7) Low Earth Orbit Satellite
A satellite orbiting the earth at an average altitude of lower than 2000 km above theearth's surface with an eccentricity of less than 0.25.
(8) Primary decision-making meeting
A meeting to determine the transition to collision avoidance operations.
(9) Primary object
Operational satellites around the Earth to be protected from collisions by thisstandard.
(10) Secondary objects
A space object that may collide with the primary object.
(11) Space Systems
It is a generic term for satellites and systems that carry out missions outside theatmosphere, such as satellites and launch vehicles.
3.2.

Definition of abbreviations

The definitions of abbreviations used in this standard are as follows.
(1) ISS (International Space Station)(2) TCA (Time of Closest Approach)4.

A basic approach to conjunction assessment and collision avoidance operation

4.1.

Requirements for development phase

The following points shall be considered during development.
(1) During the mission review process, consideration shall be given to selecting an
operational orbit in an orbit area with the lowest possible conjunction frequency.
6

JMR-016(E)(2) Consideration shall be given to the addition of a collision avoidance function, basedon (1) and the importance of the mission.
(3) If a collision avoidance function is added based on the study in (2), the propellant
required for collision avoidance maneuver shall be considered.
(4) For systems that potentially cause visibility problems (e.g., satellites not equippedwith GPS receivers, satellites covered with materials with good radio absorption
characteristics, tethers and other propagation ends, and microsatellites),consideration shall be given to improving visibility from the ground to improve orbit
determination accuracy by providing optical or radio reflection and transmission
means.
4.2.

Requirements for operation phase

Collision avoidance operations are performed to reduce the risk of collision of the primaryobject with a secondary object. To reduce the risk of collision, it is desirable to provide
the primary object with a collision avoidance maneuver capability. However, since somesatellites do not have a collision avoidance maneuver capability, this standard specifies
that the collision risk shall be assessed regardless of whether a collision avoidance
maneuver capability is provided.
According to the compliant document (3), to assess the risk, it is specified that themagnitude of the risk is determined by combining two items: "likelihood of occurrence"and "expected severity”. However, when it comes to collision events between objects
whose orbits are known (both with object radii of several centimeters or more), once acollision occurs, it not only causes loss of the primary object's function but also seriously
affects the space environment, so the expected severity of risk in the event of any collision
exceeds the acceptable level. Therefore, in effect, only the "likelihood of occurrence(probability of collision)" indicator is used to evaluate collision risk.
If risk management based on the probability of collision is not necessarily suitable suchas in the case of geostationary satellites, a collision avoidance operation policy shall be
determined in coordination with the conjunction assessment and collision avoidance
operation support organization using methods such as conjunction assessment andappropriate relative distances, etc.
5.

General requirements

5.1.

Basic requirements

When planning and executing conjunction assessment and collision avoidance operations,the organizations in charge indicated in Section 5.1.1.2 shall develop and implement
7

JMR-016(E)effective measures to minimize the risk of collision of the primary object with thesecondary object.
The organizations in charge shall include each of the following items in their activities.
(1) Efforts to reduce the risk of collisions between primary and secondary objects. To
demonstrate such efforts, the collision avoidance operational management shownin Section 5.1.1 shall be implemented.
(2) Establishment of a management system to accurately reflect the efforts describedin (1) above in each operational phase. To implement the development of such amanagement system, the requirements in 5.1.2 through 5.1.4 shall be applied
based on the collision avoidance operational management shown in Section 5.1.1.
5.1.1. Collision avoidance management
5.1.1.1. Overview
The organizations in charge as specified in Section 5.1.1.2 shall ensure that an effective
conjunction assessment and collision avoidance operation plan is prepared before thepre-launch phase and that the results are systematically managed for review.
5.1.1.2. Organizations in charge
The following organizations in charge shall assign a person in charge of managing therisk of collision between primary and secondary objects.
(1) The organization that conducts collision avoidance operations
The organization that conducts collision avoidance operations (hereinafter referred
to as “COLA team”) shall assign a person in charge of conducting collision avoidance
operations.
The COLA team basically refers to the satellite project team or the satellite
applications and operations center.
The person in charge of collision avoidance operations (hereinafter referred to as“COLA operator”) is the person who performs collision avoidance operations in the
COLA team.
(2) The organization that conducts conjunction assessment and collision avoidance
operational support
The organization that conducts conjunction assessment and collision avoidance
operational support (hereinafter referred to as “CA team”) shall assign a person in
charge of implementing conjunction assessment and collision avoidance operational
support.
The CA team basically refers to the STCC. However, this does not apply when there
8

JMR-016(E)is a separate person designated to implement conjunction assessment and collision
avoidance operational support.
The person in charge of conjunction assessment and collision avoidance operation
support (hereinafter referred to as “CA analyst”) means the person in charge ofconjunction assessment and collision avoidance operation support in the CA team.
(3) The crisis management office
The crisis management office (hereinafter referred to as “CMO”) shall assign aperson in charge of crisis management related to collision avoidance operations(hereinafter referred to as “CMO staff”). The CMO staff related to the CA consist of
personnel who will communicate with the CA analyst and the COLA operator, as
well as the assistant of the CMO director (hereinafter referred to as “CMO
assistant”) per reference document (2).
5.1.1.3. Collision avoidance management plan
The COLA team shall prepare a feasible collision avoidance operation and management
plan 1 that applies this standard in consultation with the CA team and the Safety andMission Assurance Department, and obtain approval from the JAXA Safety Review
Board. The collision avoidance operation and management plan shall include thefollowing(1) Conformity with the requirements of this standard.
(2) A series of operational procedures related to collision avoidance operations withsecondary objects (e.g., how to obtain conjunction information, conjunction
assessment timeline, and how to implement collision avoidance maneuver).
(3) A list of relevant documents, such as documents to be prepared to satisfy therequirements of this standard, application documents, etc.
(4) A description of tailoring items, if any, to this standard and the rationale for suchtailoring.
5.1.2. Requirements for the COLA team
The COLA team shall perform the following tasks
・ Implementation decisions regarding satellite operations, including collision
avoidance operations
・ Information communication regarding the above implementation decisions
・ Satellite control operations for collision avoidance operations
It corresponds to the conventional "Space Debris Avoidance Control Operating
Procedures.

1

9

JMR-016(E)5.1.3. Requirements for the CA team
The CA team shall perform the following tasks
・ Identification of secondary objects that may collide with the primary object andcalculation of collision risk
・ Notification of close approach events with high collision risk
・ Planning for collision avoidance maneuvers
・ Operation of tracking network facilities for collision avoidance operations
5.1.4. Requirements for the CMO
The CMO shall perform the following tasks
・ Collect information related to risk management and assess the situation (including
safety confirmations after collision avoidance)
・ Decide on an agency-wide response to detected risks (if a response is deemednecessary, discuss and set up countermeasures).
6.

Detailed requirements

6.1.

Basic requirements

The organizations in charge described in section 5.1.1.2 shall implement the following tominimize the risk of collisions with secondary objects.
(1) Collision risk assessment(2) Response according to collision risk level
For low earth orbit satellites, the satellite operation shall be based on Section 6.2.
For other than low earth orbit satellites, the satellite operation shall be based on a risk
assessment method using geometrical distance at the time of closest approach, etc.,
which is separately determined for each satellite2.
6.2.

Collision risk assessment

6.2.1. Collision risk assessment indicators
As an indicator to define the collision risk, the "probability of collision (Pc)," which is
calculated by considering the orbital position error and the size of the objects, shall be
used in principle. The closest approach distance and separation distance in the altitude
direction shall be treated as optional information for evaluating collision risk. The
calculation method of Pc is specified in Reference Document (4). For the relationship
For other than low earth orbit satellites, JAXA plan to add the information to thisstandard once the procedures for collision avoidance operations have matured.

2

10

JMR-016(E)between collision risk and Pc, refer to Section 4 and ANNEX A.
6.2.2. Collision risk level
To prepare for the risk of collision between primary and secondary objects, collision
avoidance operations shall be performed corresponding to the collision risk levels shown
below. In principle, the collision risk level is defined by two parameters: Pc and urgency(remaining time until TCA).
6.2.2.1. Level 1 (MONITOR)
A state in which a possible high collision risk between the primary and secondary objects
is detected, but there is sufficient time to implement a collision avoidance maneuver
before reaching TCA. At this collision risk level, the CA team shall report the latest
conjunction information to the COLA team and the CMO, and each organization shallkeep a close watch on the collision risk trend. Even primary objects that do not havemaneuver capabilities fall under this collision risk level if they meet the following
conditions.


Level 1 Conditions
・ Period: 5 days before TCA 3 to first acquisition of signal (hereinafter referred
to as “AOS”) after TCA・ Probability of collision: 1.0E-5 or higher

6.2.2.2. Level 2 (URGENT)
A state in which the collision risk between the primary and secondary objects is still high,and a collision avoidance maneuver need to be prepared and, if necessary, implemented.
At this collision risk level, the CA team shall report the latest approach status to the
COLA team, and the COLA team shall prepare for collision avoidance operations andimplement a collision avoidance maneuver if necessary. The COLA team shall givepriority to reducing the risk of collision for the primary object. If the contact informationof the secondary object operator is included in the conjunction information (Reference
Document (10)), the CA analyst shall contact the secondary object operator as much as
possible to coordinate collision avoidance operations. In addition, the report distributedby the CA analyst shall include maneuver information on the secondary object.
3Level 2 conditions (only applicable to primary objects with maneuver capability)

The remaining time until TCA is less than 120 hours.
11

JMR-016(E)・ Period: Primary decision time (see below) to first AOS after TCA・ Probability of collision: In principle, Table 1 will be applied to decide theLevel 2 transition. Even if the preparation or implementation of a collision
avoidance operation is canceled as a result of a decision made by the COLA
team, it will still fall under this collision risk level if it meets this criterion.
Table 1 Definition of Level 2 (URGENT)
Primary Decision Time (N days before TCA) 4

Probability of collision

N ≦ 2

1.0E-4 or higher

N ＞ 2

1.0E-5 or higher

Guideline for setting the primary decision-making meeting
If the COLA team decides to prepare for the collision avoidance operation in the primarydecision meeting, the time required for preparation of trajectory control for collision
avoidance (planning of collision avoidance maneuver, conjunction assessment based on
the controlled trajectory, securing ground stations for uplink/downlink, making
command plans, etc.) differs for each COLA team, so it is necessary to set a time thattakes these factors into account. Therefore, it is necessary to set the time in considerationof these factors. The specific values for N in Table 1 shall be described in the collision
avoidance management plan (Section 5.1.1.3).
Criteria for deciding whether to implement collision avoidance maneuver (at the time of
the final decision meeting)
The decision criteria for the implementation of the collision avoidance maneuver are
shown in Table 2. In addition to the criteria below, a comprehensive decision on theimplementation of the collision avoidance maneuver shall be made by considering thestatus of the satellite system of the primary object at the time of the collision (i.e.,
whether there is any risk from the implementation of the collision avoidance maneuver).
The probability of collision to be targeted in the collision avoidance operation shall be
described in the collision avoidance management plan (Section 5.1.1.3).
Table 2 Criteria for implementation of collision avoidance maneuver
Probability of

Description

Collision
4

Refers to a condition where the remaining time until TCA is less than N x 24 hours.
12

JMR-016(E)The COLA team shall prioritize the implementation of
1.0E-3 or higher

collision avoidance maneuvers over the continuity of mission
operations if the primary object has maneuver capability.

1.0E-4 to less than
1.0E-3

The COLA team shall implement collision avoidance
maneuvers considering the continuity of mission operations if
the primary object has maneuver capability.

Guideline for setting the final decision meeting
The time between the final decision meeting and the execution of the collision avoidance
maneuver depends on each COLA team and the assignment status of available groundstations. In addition, it is desirable to set the time as close to the TCA as possible to makedecisions on collision avoidance maneuvers using the latest approach information. The
final decision meeting shall be set at a time that takes these factors into account.
6.2.2.3. Level 3 (CRITICAL)A state in which the risk of collision between the primary and secondary objects is very
high, but satellite operations to reduce the collision risk (e.g., collision avoidance
maneuver) cannot be implemented. Because the collision risk cannot be reduced at thisrisk level, it is truly a high-risk condition, and the COLA team shall take the maximum
possible action.
Level 3 conditions (applicable to primary objects with maneuver capability)
・ Period: After the final decision meeting to first AOS after TCA・ Probability of collision: 1.0E-3 or higher
・ Only when satellite operations to reduce the risk of collision (e.g., collision
avoidance maneuver) cannot be implemented

Level 3 conditions (applicable to primary objects without maneuver capability)
・ Period: 2 days before TCA 5 to first AOS after TCA・ Probability of collision: 1.0E-3 or higher

6.2.3. Collision risk level transitions
A matrix of collision risk levels according to collision risk and urgency for primary objects
is shown in Figure 1. For primary objects with maneuver capability, the level shifts from5

A condition in which the remaining time until TCA is less than 48 hours.
13

JMR-016(E)Level 1 to Level 2 after the primary decision time. If the probability of collision is 1.0E3 or higher and satellite operations to reduce the collision risk cannot be implemented,
the risk level moves to Level 3. On the other hand, the risk level for the primary object
without maneuver capability moves to Level 3 only when the probability of collision is
1.0E-3 or higher at the time two days before the TCA.

Figure 1 Transition diagram of collision risk levels
6.3.

Actions according to the collision risk level

It is necessary to perform collision avoidance operations corresponding to the collisionrisk levels specified in 6.2.2 and to communicate and share information with relevantorganizations. This section defines the information communication flow and the type of
information to be communicated (sender, receiver, contents, and timing) for each collisionrisk level. The basic method of "notification" is e-mail, while "communication" and"coordination" can be handled appropriately by telephone, etc. in addition to e-mail.
This standard describes only the communication flow between the organizations incharge of JAXA, and the procedures for communicating within an organization(including the director in charge) shall follow the procedures established for each
14

JMR-016(E)organization. In addition, the crisis management office shall communicate necessary
information per the applicable document (2).
6.3.1. Primary object with maneuver capability
Figure 2 shows the information communication flow at each collision risk level. The typesof information to be communicated at each collision risk level (sender, receiver, content,
and timing of transmission) are specified in ① through ⑥ below.

Figure 2 Information communication flow for a primary object with maneuver capability① Notification of conjunction status
The CA analyst shall notify the COLA operator and the crisis management office of thelatest conjunction status as indicated below. In principle, notification shall be madeduring the day shift when information is updated.
In addition, when the CA analyst detects a conjunction event that meets the definitionof collision risk level 2, the CA analyst contacts the CMO staff in charge of the CA team
via e-mail (The address of the emergency mobile phone for the person in charge of crisis
management shall be added to the e-mail shown in Figure 2 ①. 6) In addition, the CA
Once added as a recipient, it shall not be removed until there is no longer a risk of
relevant conjunction.

6

15

JMR-016(E)analyst shall phone the COLA operator to coordinate the schedule for the primarydecision meeting.
Subject: [Notification (or update)] Secondary object approach notification (primary object
name x secondary object name, TCA)
(1) Secondary object: OBJECT number, name(2) TCA: year, month, day, hour, minute, second UTC(3) Relative date and time: X days later(4) Probability of collision: X (no unit)(5) Closest approach distance: X m(6) Distance of separation in altitude direction ：X m
(7) Orbital position error: primary and secondary objects, respectively(8) Others: the existence of a maneuver plan, simulation results, etc.
② Notification of decision on whether to shift to collision avoidance operations
After the primary decision meeting, the COLA operator shall notify the CA analyst andthe crisis management office of the results of the decision on whether to shift to collision
avoidance operations.
Subject: [Notification] Result of the decision to shift to collision avoidance operation(1) Result of the decision to transition to collision avoidance operations (GO/NOGO)(2) The rationale for the transition decision(3) Secondary object: OBJECT number, name(4) TCA: year, month, hour, minute, second UTC(5) Probability of collision: X (no unit) *Optional(6) Closest approach distance: X m *Optional(7) Date and time of the final decision meeting (if GO)③ Notification of collision avoidance maneuver plan
The CA analyst shall notify the COLA operator of the planned collision avoidance
maneuver values. Note that this notification is not required if the collision avoidance
maneuver plan has been determined at the time of the primary decision meeting.
Subject: [Notification (or Update)] Issue (or Update) collision avoidance maneuver plan
(1) Maneuver epoch: year, month, hour, minute, second UTC(2) Maneuver quantity: X m/s
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JMR-016(E)(3) Secondary object: OBJECT number, name(4) TCA after avoidance: year, month, hour, second, UTC(5) Probability of collision after avoidance: X (no unit)(6) Closest approach distance after avoidance: X m④ Notification of decision to implement or not to implement collision avoidance
maneuverAfter the final decision meeting, the COLA operator shall notify the CA analyst and thecrisis management office of the results of the decision to implement or not to implement
the collision avoidance maneuver.
Subject: [Execution (or Cancellation)] Result of the decision to implement collision
avoidance maneuver(1) Result

of

the

decisiontoimplement

collision

avoidance

maneuver(execution/cancellation)(2) Rationale for decision(3) Maneuver epoch: year, month, hour, minute, second UTC(4) Maneuver quantity: X m/s *Optional(5) Secondary object: OBJECT number, name(6) TCA after avoidance: year, month, hour, second, UTC *Optional(7) Probability of collision after avoidance: X (no unit) *Optional(8) Nearest approach distance after avoidance: X m *Optional(9) Timing when a collision avoidance maneuver result can be confirmed (time offirst AOS)
⑤ Notification of transition to Level 3 (CRITICAL)
If it is found that satellite operations to reduce the risk of collision (collision avoidance
maneuver, etc.) cannot be implemented, and the operation is shifted to collision risk level
3, the COLA operator shall call the CA analyst and the CMO staff in charge of the COLA
team, to that effect. Thereafter, the CA analyst shall notify the CMO staff in charge of
the CA team, and the CMO staff in charge of the COLA team shall notify the CMO
assistant by phone call that the collision risk level has been shifted to Level 3. When
notified by phone call, the timing when the satellite status can be confirmed after theclosest approach shall also be notified.
⑥ Level 2 (URGENT) or Level 3 (CRITICAL) release notification
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JMR-016(E)The COLA operator shall notify the COLA operator and the crisis management office ofthe results of the implementation of the collision avoidance maneuver and the status of
the primary object after the closest approach time has passed. If the collision risk level
cannot be released due to a collision or other reason, the COLA operator shall inform thecrisis management office to that effect and take action per the applicable document (2).
Subject: [Notification] Result of status confirmation after closest approach (Satellite
name)(1) Results of collision avoidance maneuver implementation(2) Status of the primary object after the TCA(3) The release of a Level 2 or Level 3 crisis management
6.3.2. Primary object without maneuver capability
Figure 3 shows the information communication flow at each collision risk level. The typesof information to be communicated at each collision risk level (sender, receiver, content,
and timing of transmission) are specified in ① through ④ below.

Figure 3 Information communication flow for a primary object without maneuver
capability① Notification of conjunction status
The CA analyst shall notify the COLA operator and the crisis management office of thelatest conjunction status. In principle, notification shall be made during the day shift18

JMR-016(E)when information is updated. The information to be communicated shall be per Section
6.3.1 (1).
② Notification of transition to Level 3 (CRITICAL)When a conjunction event that meets the definition of collision risk level 3 is detected,
the CA analyst shall notify the COLA operator and the CMO staff via e-mail that a
conjunction that meets collision risk level 3 exists, along with the latest conjunction
status.
The CA analyst shall also inform the COLA operator and the CMO staff in charge of the
CA team, to that effect by phone call. Thereafter, the COLA operator shall notify the
CMO staff in charge of the COLA team, and the CMO staff in charge of the COLA teamshall notify the CMO assistant by phone call that the collision risk level will be moved
to Level 3.
Subject: [Notification] Notification of transition to collision risk level 3 (primary object
name x secondary object Name, TCA)
(1) A statement that the conjunction falls under level 3 (CRITICAL)(2) Secondary object: OBJECT number, name(3) TCA: year, month, hour, second, UTC(4) Relative date and time: X days later(5) Probability of collision: X (no unit)(6) Closest approach distance: X m(7) Distance of separation in altitude direction: X m(8) The reason why collision avoidance operations cannot be performed③ Notification of operation pass information after TCA
The COLA operator shall secure an operation pass to check the status of the primaryobject after TCA, and shall notify the CA analyst and the crisis management office of theinformation regarding the operation pass for checking the status of the primary object.
Subject: [Notification] Operation pass after closest approach (Satellite name)(1) Secondary object: OBJECT number, name(2) TCA: year, month, hour, minute, second UTC(3) Operation pass time and station name after the TCA④ Level 3 (CRITICAL) release notification
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JMR-016(E)The COLA operator shall notify the CA analyst and the crisis management office of thestatus of the primary object after the TCA. If the collision risk level cannot be released
due to a collision or other reason, the action shall be taken per the applicable document(2).
Subject: [Notification] Result of status confirmation after closest approach (Satellite
name)(1) Status of the primary object after the TCA(2) The release of a Level 3 crisis management
7.

Contact for inquiries
In the Metadata section of the Conjunction Data Message (Reference Document (10)),which contains the conjunction information, there is a form to provide contact
information to the satellite operations organization. To respond to inquiries about
conjunction events with external organizations, the CA team publishes the contact
information in the Conjunction Data Message so that the contact information is listed
in the conjunction information.

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JMR-016(E)

ANNEX A.

Effectiveness of collision risk assessment using a probability of collision

As candidate indicators to define the likelihood of occurrence of collision risk, theapproach distance and the separation distance in the altitude direction at the TCA wereused in space debris collision avoidance operations until FY 2016. However, as examples(a) and (b) in Figure 4 show, even if the closest approach distance is small, if themagnitude of the orbital position error is extremely large or small relative to the closest
approach distance, the collision risk may be judged to be small, reducing unnecessary
collision avoidance operations.

Figure 4 Relationship between orbital error and collision risk between satellites(primary objects) and space debris (secondary objects)

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JMR-016(E)

ANNEX B.

Comparison with collision avoidance criteria of other space agencies

For collision avoidance operations for other space agencies and the ISS, several
thresholds for the probability of collision, as indicated in Sections 6.2.1 and 6.2.2, havebeen established and examples are given below.


The criteria for implementing collision avoidance maneuver on the ISS is when theprobability of collision is 1.0E-4 or higher (red light level). However, if the probabilityof collision becomes smaller than 1.0E-4 after the detailed maneuver plan isprepared, the decision to abort can be made with the consent of the flight director
two orbits (approximately three hours) before the maneuver. (Reference Document(5))

The criteria for implementing collision avoidance maneuver in NASA is when theprobability of collision is greater than 1.0E-4 or the closest approach distance is lessthan the Hard-Body-Radius (sum of the radii of the primary and secondary objects).
Then, for avoidance operations, it is recommended to reduce the probability ofcollision to 1.5 times the logarithmic ratio (=probability of collision 3.2E-6). In thiscase, the probability of collision with another object should be lower than 1.0E-4.
(Reference Document (1))



The criteria for implementing collision avoidance maneuver in CNES are "whenradar observation of a secondary object is available and the probability of collision
is 1.0E-3 or higher" or "when radar observation of a secondary object is not available
but the probability of collision is 1.0E-2 or higher". An alert is issued when the
maximum probability of collision is 1.0E-4 or higher, and a detailed analysis isconducted when the probability of collision is 1.0E-3 or higher. (Ref. (6)(7))



The criteria for implementing collision avoidance maneuver in the ESA is when theprobability of collision is 1.0E-4 or higher at the time of the final decision (usually
within TCA-1 day). This probability of collision threshold is a value set from thetrade-off between "the rate of reduction of collision risk during the satellite operation
period" and "the number of alerts issued and collision avoidance maneuvers
performed per year". (Ref. (8)(9))

Considering the above situation, the thresholds are set in the range of 1.0E-4~1.0E-2
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JMR-016(E)for the probability of collision in each agency's decision to implement collision
avoidance maneuver, and the criteria for judging the implementation of collision
avoidance maneuver set in this standard (Table 2) are also consistent withinternational standards.

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