General

JERG-0-047A (E)

Safety Standard for Controlled Re-entry

Revision A
April 28, 2021

Japan Aerospace Exploration Agency (JAXA)JERG-0-047A (E)This is an English translation of JERG-0-047A. Whenever there is anything ambiguous in thisdocument, the original document (the Japanese version) shall be used to clarify the intent of therequirement.

Disclaimer
The information contained herein is for general informational purposes only. JAXA makes
no warranty, express or implied, including as to the accuracy, usefulness or timeliness of any
information herein. JAXA will not be liable for any losses relating to the use of theinformation.

JERG-0-047A (E)

Table of contents
1.

Purpose ........................................................................................................ 1

2.

Applicability ................................................................................................... 1

3.

Applicable and reference documents .............................................................. 2
3.1.

Applicable documents .............................................................................. 2

3.2.

Reference documents .............................................................................. 2

4.

Fundamental methodology for public safety .................................................... 2

5.

Functional requirements for controlled re-entry .............................................. 2
5.1.

Flight system ........................................................................................... 2

5.2.

Ground system ........................................................................................ 3

6.

Planning and pre-operational assessments .................................................... 3
6.1.

Determination of the planned re-entry area .............................................. 3

6.1.1. Within the territory of a nation............................................................ 3
6.1.2. Outside of territory ............................................................................ 3
6.2.

Expected re-entry area (Footprint) ........................................................... 3

6.3.

Expected number of casualties (Ec) ......................................................... 4

6.4.

Consideration for operational sequence ................................................... 4

6.5.

Availability of command and telemetry ..................................................... 4

7.

Notification for air and maritime traffic safety ................................................. 4

8.

Collision avoidance during the re-entry sequence ........................................... 5

9.

Operational requirements .............................................................................. 5
9.1.

Preparation of a controlled re-entry .......................................................... 5

9.2.

Determination of Go / No-go .................................................................... 5

9.3.

Execution ................................................................................................ 5

9.4.

Post touch down ...................................................................................... 6

10.

Safeguarding action for fallen objects or materials ...................................... 6

11.

Environmental effects ................................................................................. 6

12.

Authority .................................................................................................... 6

13.

Organization ............................................................................................... 6

14.

Definition of technical terms ....................................................................... 6i

JERG-0-047A (E)1.

PurposeThe Japan Aerospace Exploration Agency (JAXA) established this standard

for re-entry vehicles undergoing re-entry operations, from orbit to the ground, toavoid unacceptable risk to the public and the environment.
The requirements related to orbital debris mitigation documented in theapplicable document (2) are still applicable unless contradicted by therequirements herein.
2.

Applicability
This standard is applicable to re-entry vehicles developed and/or operated by

JAXA. The term “re-entry vehicle” in this standard is defined as follows.


A vehicle that is designed and planned to land on Earth after re-enteringfrom orbit. In case there are supporting flight systems that are required toachieve a nominal re-entry sequence, those flight systems are also within
the scope of compliance to this standard.



A vehicle that re-enters to the designated area on Earth from orbit for safe
disposal.

The following re-entry vehicles are exempted from the application of thisstandard.


Manned systems.

Winged systems.

This standard may be applied to a winged vehicle whose control capability inthe atmosphere is more like a capsule. In the case of application for suchvehicles, applicable paragraphs will be determined on a case-by-case basis.
This standard may be partially applied to re-entry from the planetary orbit.
Application of each paragraph will be determined based on the mission
characteristics. Examples include the following.
-

The risk of natural re-entry is relatively low because loss of re-entry
function will result in no re-entry rather than uncontrolled natural re-entry.

-

Collision avoidance is unfeasible because of the current tracking
capability.

The risk for ground operators who work in the vicinity of or within the footprint
for search and recovery shall be evaluated per the standard system safety
approach documented in the applicable document (1).
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JERG-0-047A (E)3.

Applicable and reference documents

3.1. Applicable documents
The following documents are applicable where referred to. All documents
shall be the latest version unless otherwise specified.
(1) JMR-001 System Safety Standard.
(2) JMR-003 Space Debris Mitigation Standard.
(3) (Intentionally Blank).
(4) 規 定 第 15-11 号 危 機 管 理 室 設 置 規 程 (Rule for risk control office).
(5) 規 程 第 16- 3 号 安 全 審 査 委 員 会 規 程 (Rule for safety review committee).
(6) ICAO Annex 15 Aeronautical Information Services .
3.2. Reference documents(1) NASA-STD-8719.14A Process for Limiting Orbital Debris
4.

Fundamental methodology for public safety
The following methodology is the basis of this standard to minimize t he risk to

the public caused by the attempt at controlled re-entry. It is also important tosatisfy risk acceptance criteria as the result of the safety measures examinedbased on the applicable document (1).
(1) Minimize human casualty risk by keeping the public away from the expected
re-entry area, utilizing proper notification systems such as for air andmaritime traffic.
(2) The execution of the re-entry maneuvers can be done when achieving toensure the safe controlled re-entry. In other words, ensuring all objects fallwithin the controlled area.
5.

Functional requirements for controlled re-entry

5.1. Flight system
The flight system shall have the following functions :(1) Function that determines the trajectory and attitude of a spacecraft.
(2) Telemetry that will notify system state to the ground within a necessaryinterval for the support of the Go / No-go decision.
(3) Command acquisition from the ground for execution of a re-entry
maneuver.
(4) Function to prevent unintentional execution of a re-entry maneuver.

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JERG-0-047A (E)5.2. Ground system
The ground system shall have the following functions:(1) Function to validate the trajectory and attitude of a spacecraft.
(2) Function to permit or command execution of a re-entry maneuver.
6.

Planning and pre-operational assessments

6.1. Determination of the planned re-entry area
6.1.1. Within the territory of a nation
In case that any part of the planned re-entry area is within the territory of anation, the plan must comply with the regulation, safety requirements , and/or
direction of the responsible government officials.
6.1.2. Outside of territory
Any part of the planned re-entry area:(1) shall be at least 100 km away from the coast line;(2) should be outside of any Exclusive Economic Zone (EEZ) practically as
far as possible;(3) should be clear of heavy traffic routes, where the heavy traffic routes
should be determined from information from officials in charge of therelated regions;(4) should be clear of any offshore plants such as oil and natural gas
Installations, where naval warnings and information from the International
Seabed Authority (ISA) would be recommended references.
6.2. Expected re-entry area (Footprint)
The footprint shall consider the following assumptions and conditions.
(1) The footprint shall envelope the three-sigma dispersion area for all
harmful fragments. Three-sigma dispersion is calculated based on thevariance of initial conditions such as velocity and angle, and dispersionof the atmospheric concentration.
(2) Any parameter other than (1) would also be included in three-sigma
calculation in case that the parameter and its deviation would have asignificant effect on the size or location of the area.
(3) For re-entry vehicles that utilize aerodynamic control in the atmosphere,
the footprint shall envelope a touchdown point based on the maximum
navigation capability, or three-sigma of the nominal control function.
(4) A fragment with at least 15 J of kinetic energy shall be considered in thecalculation of the footprint.
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JERG-0-047A (E)(5) The trajectory upstream and downstream of the footprint in the same
orbit should not go over a metropolitan area to minimize the risk of highor low delta-V at the re-entry maneuver.
6.3. Expected number of casualties (Ec)The expected number of casualties (Ec) shall satisfy the following criteria
considering all fragments with at least 15 J of kinetic energy.
- The criterion defined in the applicable document (2), as a total of the cases(1) through (3).
- The criterion defined in annex1, as a total of the cases (1) and (3).
(1) Successful re-entry with all fragments within the expected re-entry area.
[Casualties inside the footprint, if any.](2) Natural re-entry resulting from the loss of re-entry function. [System
reliability for re-entry related functions are taken into account in thecalculation.](3) Unsuccessful (failed) re-entry that causes the footprint fall outside of theplanned location. [Probability of failure during re-entry maneuver is taken
into account in the calculation.]
Note: annex1 is not available to the public.
6.4. Consideration for operational sequence
The operational sequence for re-entry shall consider the monitoring of healthstatus of the flight system as possible to continue in late as practical.
6.5. Availability of command and telemetry(1) Communication links for command and telemetry shall be available until
completion of the re-entry maneuver. Communication links shall be capableof transmitting all necessary data for validation as required in section 6.4.
(2) Telemetry of the flight system should be monitored as long as it is available,
even after the re-entry maneuver.
7.

Notification for air and maritime traffic safety
The following notification process should be followed to minimize risk for air

and maritime traffic. Notification basically includes area and time to be cautious.
(1) For air traffic: The notification processes utilizing the Aeronautical
Information Package (AIP) and Notice to Airmen (NOTAM) are defined in theapplicable document (6). Detailed processes and procedures should becoordinated with the appropriate government official. Information regarding
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JERG-0-047A (E)any modification affecting air traffic control should be communicatedimmediately per the agreed procedure.
(2) For maritime traffic: Several notification processes (e.g. NAVAREA, NAVTEX
and so on) are in place. Detailed processes and procedures should becoordinated with the appropriate government official.
8.

Collision avoidance during the re-entry sequence
Collision avoidance against any space object shall be implemented per theapplicable document (2), paragraph 5.5.2.
9.

Operational requirements

9.1. Preparation of a controlled re-entry
The following readiness shall be confirmed before a re-entry operation.
(1) Facility and equipment utilized for re-entry. Interface checkout shall also
be completed.
(2) All nominal and off-nominal procedures, and necessary training.
(3) Communication procedure and/or a manual including an emergency plan.
(4) Notification as defined in section 7.
9.2. Determination of Go / No-go
Go or No-go shall be determined at an appropriate time in the re-entry
sequence as described in section 6.4. Controlled re-entry may not be allowed if
there is no possibility of a proper re-entry maneuver per the following status
information.
(1) Trajectory (position and velocity) and attitude.
(2) Health status of necessary functions (such as navigation control andpropulsion system) for controlled re-entry.
9.3. Execution(1) The status information of the flight system, ground system , and otherrelated systems shall be continuously monitored until execution of the reentry maneuver.
(2) In case of abort and retry, the readiness for re-entry operation detailed in
section 9.1 shall be reconfirmed.

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JERG-0-047A (E)9.4. Post re-entry(1) The actual touchdown location of a system and/or a footprint calculated
from the result of re-entry burn will be communicated, if necessary.
(2) If any part of the flight system falls outside of the expected re-entry area
and could be within the territory of a nation, the necessary warning shall begiven to the government officials. It should also be confirmed that there isno danger to aircraft, ships, or other vehicles due to off-nominal re-entry
even outside of territory. The emergency plan may be used, if required.
(3) In an off-nominal situation that the flight system is incapable of performing
controlled re-entry, the emergency plan will be used based on the expectedrisk of natural re-entry.
10. Safeguarding action for fallen objects or materials
If there are any fallen objects or materials that could be a threat to public
safety on the ground, safeguarding action such as recovery, decontamination,and cleaning shall be implemented.
11. Environmental effects
The assessment is necessary to do for the expected fallen objects(fragments) on the ground in the planned re-entry area. The countermeasures
for it shall be taken when impact of safety is expected.
12. Authority
The JAXA Safety Review Committee defined in the applicable document (5) isthe authority for the approval of requirements herein.
13. Organization
There shall be an organization responsible for the execution of controlled reentry. This organization will ensure that the upper level management is informed
immediately of any safety issues or mishaps.
14. Definition of technical terms
The following definitions are specifically used in this standard.

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JERG-0-047A (E)Re-entry:

vehicle A vehicle that is designed and planned to land on Earth after
re-entering from orbit. In case there are supporting flightsystems that are required to achieve a nominal re-entry
sequence, those flight systems fall under the application ofthis standard.
 A vehicle that re-enters to the designated area on Earth fromorbit for safe disposal.
Manned systems are exempted from the application of thisstandard.

Re-entry:maneuverThe maneuver that moves the vehicle into the re-entry
trajectory. Maneuvers for parking or interim orbits are not partof a re-entry maneuver.

Expected:

The quantitative human casualty risk associated with fallen

number ofobjects on the ground in the event of spacecraft re-entry. A

casualties

detailed definition is given in the applicable document (2),(Ec)

paragraph 3.1(15).

Planned re-:entry area

Designated area indicated with a closed borderline on a map,
which is investigated and evaluated as a possible landing
location of a vehicle and all objects generated through a reentry breakup event.

Expected reentry area:

Calculated area within which a vehicle and all objects
generated through a re-entry breakup event must touchdown,
based on the parameters expected for the actual timing of there-entry event.

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