The Ethical Use of Outer Space - Ethical Engineering for International Development and Environmental Sustainability - page 121

weeks of 2007. On 11 January 2007, the Chinese conducted an antisatellite test,
destroying one of their own satellites with an interceptor, and on 19 February, a
Russian rocket body exploded. As a result of these two incidents, the amount of
large space debris (greater than 10 cm in diameter) in heavily used orbits increased
by over 20%.
Space debris is recognised as a growing problem, affecting military, commercial
and scientifi c space systems. In a worst case military scenario, a debris collision
with a militarily sensitive satellite could be interpreted as an attack. If this were to
occur at a time of international tension, with little time for careful consideration, it
could lead to a devastating retaliation. Currently radars can give warnings of possi-
ble collisions with objects larger than 10 cm (the International Space Station has
had to be repositioned a number of times for fear of a possible collision), but there
are at least 100,000 objects in the 1-10 cm range and the amount of debris in space
is increasing at a rate of around 4% per year. Plotting a way through is becoming a
major problem for spacecraft aiming to leave the near-Earth environment, and
according to Prof Heiner Klinkrad, the head of the European Space Agency's (ESA)
Space Debris Offi ce:
There is a consensus among debris researchers that the present orbit debris-environment is
at the rim of becoming unstable within a few decades, a phenomenon that is commonly
known as the Kessler Syndrome, 13 and that only active removal of fi ve to 10 large objects
per year can reverse the debris growth, 14

The results of research presented at the conference where this statement was
made demonstrated the need for much stronger international agreements on the use
of space.

5 A Tragedy of the Commons

The global and outer space environments may both be considered as commons. 15 As
such they are valued resources that lie outside the jurisdiction and sovereignty of
any individual state. The commons of the global environment include the climate
(and any changes in it), the ozone layer, the oceans, etc. The commons of space

13 The Kessler syndrome was proposed by the NASA scientist Donald J. Kessler in 1978; it occurs
when the density of objects in low Earth orbit is high enough that collisions cause a cascade of
debris to the extent where the distribution of debris in orbit could render space exploration, and
even the use of satellites, unfeasible for the future. (See 'Collision Frequency of Artifi cial Satellites:
The Creation of a Debris Belt' by Donald J. Kessler and Burton G. Cour-Palais, Journal of
Geophysical Research 83: 2637-2646, 1978.)
14 At the 6th European Conference on Space Debris in Darmstadt, Germany, held in April 2013 -
see the report '“Urgent need” to remove space debris' published on 25th April 2013 by BBC
science correspondent Jonathan Amos at http://www.bbc.co.uk/news/

science-environment-22299403
15 Commons are traditionally defi ned as elements of the environment that are shared, used and
enjoyed by all.