ISO 14222:2022

INTERNATIONAL ISO
STANDARD 14222
Second edition
2022-03
Space environment (natural and
artificial) — Earth's atmosphere from
ground level upward
Environnement spatial (naturel et artificiel) — Haute atmosphère
terrestre
Reference number
ISO 14222:2022(E)
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© ISO 2022
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
ii
ISO 14222:2022(E)
Contents  Page
Foreword .iv
Introduction .v
1 Scope . 1
2  Normative references . 1
3  Terms and definitions . 1
4  Symbols and abbreviated terms.6
5  General concept and assumptions .7
5.1 Earth's atmosphere model use . 7
5.1.1 General . 7
5.1.2 Application guidance . 7
5.2 Earth wind model use . 8
5.3 Robustness of standard . 8
5.4 Long-term changes of the atmosphere . 8
Annex A (informative) Neutral atmospheres .10
Annex B (informative) Natural electromagnetic radiation and indices .32
Bibliography .47
iii
ISO 14222:2022(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 second edition cancels and replaces the first edition (ISO 14222:2013), which has been technically
revised.
The main changes are as follows:
— updated formulae, references to models, indices and links to websites;
— this document now applies to the Earth's atmosphere from ground level upward through the
exosphere.
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 14222:2022(E)
Introduction
This document provides guidance for determining the properties of the Earth’s atmosphere from
ground level upward to the exosphere.
In the atmospheric regions up to approximately 100 km, a detailed knowledge of the average structure
of the atmosphere as a function of geographic location, time in the year and solar activity is critical
for the design of aircraft, balloon payloads, rocket launch activities and many other facets of modern
society. The maximum departures from average conditions also need to be understood in order to
provide a margin of safety in design and in operations. These features are included in this document.
A good knowledge of temperature, total density, concentrations of gas constituents, and pressure in
the region above about 100 km is important for many space missions exploiting the low-earth orbit
(LEO) regime below approximately 2 500 km altitude. In addition to the causes of variation of the
atmosphere up to 100 km, geomagnetic processes may seriously affect the structure and dynamics
of the thermosphere. Aerodynamic forces on the spacecraft, due to the orbital motion of a satellite
through a rarefied gas which itself can have variable high velocity winds, are important for planning
satellite lifetime, maintenance of orbits, collision avoidance manoeuvring and debris monitoring,
sizing the necessary propulsion system, design of attitude control system, and estimating the peak
accelerations and torques imposed on sensitive payloads. Surface corrosion effects due to the impact
of large fluxes of atomic oxygen are assessed to predict the degradation of a wide range of sensitive
coatings of spacecraft and instruments. The reactions of atomic oxygen around a spacecraft can also
lead to intense “vehicle glow”.
The structure of Earth’s atmosphere and internationally accepted empirical models that specify the
details of the atmosphere are included in this document. The annexes and references provide a detailed
description the details of those models. The purpose is to create a standard method for specifying
Earth's atmosphere properties (density, temperature, wind etc.) at all altitudes from ground level
upward, including the low Earth orbit regime now widely-used for space systems and space operations.
The details of those models are included in Annex A.
Annex B provides a detailed description of the electromagnetic radiation and solar and geomagnetic
indices.
v
INTERNATIONAL STANDARD ISO 14222:2022(E)
Space environment (natural and artificial) — Earth's
atmosphere from ground level upward
1 Scope
This document specifies the structure and properties of the Earth’s atmosphere from ground
level upward. It provides internationally accepted empirical models that specify the details of the
atmosphere. It also refers to widely-accepted physical models providing insight into the physical and
chemical processes driving the response of the atmosphere.
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
homosphere
region of the atmosphere that is well mixed
Note 1 to entry: The major species proportional concentrations are independent of height and location.
Note 2 to entry: This region extends from 0 km to ~100 km and includes the temperature-defined regions of the
troposphere (3.2) (surface up to ~6 km to 18 km altitude), the stratosphere (3.3) (~6 km to 18 km up to 50 km
altitude), the mesosphere (3.4) (~50 km up to about 90 km altitude), and the lowest part of the thermosphere (3.5)
(~90 km to 125 km).
3.2
troposphere
lowest layer of the Earth’s atmosphere
Note 1 to entry: It is also where nearly all weather conditions occur.
Note 2 to entry: The troposphere contains approximately 75 % of the atmosphere’s mass and 99 % of the total
mass of water vapour and aerosols. The average height of the tropopause is 18 km (11 mi; 59 000 ft) in the tropics,
17 km (11 mi; 56 000 ft) in the middle latitudes, and 6 km (3.7 mi; 20 000 ft) in the polar regions in winter. The
global average height of the tropopause is 13 km.
Note 3 to entry: The lowest part of the troposphere, where friction with the Earth's surface influences air flow,
is called the planetary boundary layer. The boundary layer is typically a few hundred metres to 4 km deep
depending on the landform, latitude, season and time of day. The upper boundary of the troposphere is the
tropopause, which is the border between the troposphere and stratosphere (3.3). The tropopause is an inversion
layer, where the air temperature ceases to decrease with height and remains constant through its thickness.
ISO 14222:2022(E)
3.3
stratosphere
second major layer of Earth’s atmosphere, immediately above the troposphere (3.2) and below the
mesosphere (3.4)
Note 1 to entry: The stratosphere is stratified (layered) in temperature, with warmer layers higher and cooler
layers closer to the Earth; this increase of temperature with altitude is a result of the absorption of the Sun's
ultraviolet radiation by the ozone layer. This is in contrast to the troposphere (3.2), near the Earth's surface,
where temperature decreases with altitude. The border between the troposphere (3.2) and stratosphere, the
tropopause, marks where this temperature inversion begins. Near the equator, the stratosphere starts at as high
as 18 km, around 17 km at midlatitudes, and at about 6 km at the poles. Temperatures range from an average
of −51 °C near the tropopause to an average of −15 °C near the stratopause [the boundary with the mesosphere
(3.4)]. Stratospheric temperatures also vary within the stratosphere as the seasons change, reaching particularly
low temperatures in the polar night (winter). Winds in the stratosphere can far exceed those in the troposphere
(3.2), reaching near 60 m/s in the Southern polar vortex.
3.4
mesosphere
layer of the Earth’s atmosphere that is directly above the stratosphere (3.3) and directly below the
thermosphere (3.5)
Note 1 to entry: In the mesosphere, temperature decreases as the altitude increases. This characteristic is used
to define its limits: it begins at the top of the stratosphere (3.3) (sometimes called the stratopause), and ends at
the mesopause, which is the coldest part of Earth's atmosphere with temperatures frequently below −143 °C. The
exact upper and lower boundaries of the mesosphere vary with latitude and with season (higher in winter and at
the tropics, lower in summer and at the poles), but the lower boundary is usually located at heights from 50 km to
65 km above the Earth's surface and the upper boundary (mesopause) is usually around 85 km to 100 km.
Note 2 to entry: The stratosphere (3.3) and the mesosphere are collectively referred to as the “middle atmosphere”,
which spans heights from approximately 10 km to 100 km. The mesopause, at an altitude of 80 km to 90 km,
separates the mesosphere from the thermosphere (3.5) – the second-outermost layer of the Earth's atmosphere.
This is also approximately the same altitude as the turbopause. Below the turbopause, different chemical species
are well mixed due to turbulent eddies. Above this level the atmosphere becomes non-uniform; also, above the
turbopause, the scale heights of different chemical species differ by their molecular masses.
3.5
thermosphere
region of the atmosphere between the temperature minimum at the mesopause (~90 km) and the
altitude where the v
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