The Ethical Use of Outer Space - Ethical Engineering for International Development and Environmental Sustainability - page 104

problems arising from the military use of space and the current projects that threaten
space security will be outlined. Section 4.4 emphasises the need to be aware of, and
care for, the space environment, and this also leads to a discussion of the problems
of an unregulated use of space in terms of a tragedy of the commons in Sect. 4.5 .
Section 4.6 then looks at the ethical situation regarding the just and benefi cial use of
the space environment, and the existing international treaties and agreements are
outlined along with the adopted procedural mechanisms. Finally, Sect. 4.7 con-
cludes with some suggestions for future progress.

2 Just What Is Outer Space?

So, where does the Earth's atmosphere end and outer space begin? The atmosphere
is a relatively thin layer of gases surrounding the Earth, held there by the planet's
gravity. Among other things, it contains the oxygen we need to survive and the
weather patterns that have helped determine our development, and it protects us
from the harmful ultraviolet radiation emitted by the Sun. Travelling upwards from
the Earth's surface takes you through various layers as shown in Table 4.1 .
O f fi cially, outer space begins at the Karman line - at an altitude of 100 km above
sea level. At least this is the defi nition accepted by the Fédération Aéronautique
Internationale (FAI), the international standard setting organisation for aeronautics
and astronautics. Theodore von Kármán calculated that at this altitude, the atmo-
sphere becomes so thin that, in order to gain enough aerodynamic lift, aeroplanes
would need to travel at orbital speed.
This defi nition is the one used in the formulation of treaties and the construction
of space law and helps determine how outer space is perceived by nations and how
they believe it should be used and cared for.

Table 4.1 The Ea rth's atmosphere

Height above
sea level
(miles)

Height above
sea level (km) Region

Exosphere Where the atmosphere merges with outer

space

>700 >440

Thermosphere Almost a vacuum and heated by solar

radiation - temperatures may reach 2,000 °C

80-700 50-440

Mesosphere Temperature decreases with increasing

height - temperatures may fall to −143 °C.
Region where most meteors burn up

50-80 31-50

Stratosphere Contains the ozone layer which absorbs

harmful ultraviolet radiation from the Sun

12-50 7-31

Troposphere Contains most of the weather. Mostly heated

by energy emitted from the surface

0-12 0-7