The Consequences of a Space War
by Li Bin*
Moves in preparing
for Space War
We have seen some explicit
moves in the United States in recent years in preparing for space
wars. On May 8, 2001, US Defense Secretary Rumsfeld announced the
"Space Management and Organization Initiative," directing
the military to engage in organization, training and equipment for
swift, continuous, offensive and defensive space operations.1
This plan has apparently gone beyond the approaches of passive defense
in space, for example by hardening satellites to survive attacks,
and turned to seeking capabilities for offensive approaches. Also,
some US defense companies have been making efforts in recent years
to develop weapons for offensive space operations. For example, Boeing
has the KE-ASAT (Kinetic Energy Anti-Satellite) program to develop
weapons that are used to attack hostile satellites and the program
has received funding from the US government for more than ten years.
2
The incentives behind these moves toward space war preparation in
the US seem strange, however, given US dependence on space for both
military and civilian uses. More than half of the satellites in space
belong to US. American decision makers understand that US security
and daily life depend largely on these satellites that are vulnerable
to space warfare. 3 The US also has
the technical and economic potential to expand its presence in space,
regardless of whether there is international cooperation or competition
in the uses of space, provided the space environment remains a peaceful
one. To maintain or strengthen the US dominance in space, it would
seem that the US should avoid violent conflicts in space that could
hurt US assets there. The US should be eager to ban space warfare,
or at least it should encourage international dialogue toward such
a goal. The fact is, however, that the US continues to reject proposals
aimed at negotiating a ban on space weapons. 4
Incentives
for war preparation
It seems that US decision
makers prefer war preparation in space rather than peaceful approaches.
Such a choice logically should be based on a belief that a war in
space is more preferable to the US than peaceful cooperation or peaceful
competition in the use of space. In another words, these decision
makers may believe that the US can certainly win a space war that
would then allow the US to increase its dominant position in space.
It may help in understanding the incentives of US space war preparation
if we recall the dynamics of the nuclear arms race in the 1950s and
1960s. The main motivations that drove the US and the former Soviet
Union to pursue quantitative nuclear development stemmed both from
the fear of being militarily defeated and from the hope of defeating
the other side with nuclear weapons in a preemptive strike. As survivable
nuclear weapons were deployed, however, US and Soviet decision makers
recognized that a nuclear war could not be won without suffering unacceptable
levels of damage through nuclear retaliation. This realization led
to a slowing of the quantitative arms race as both sides sought limitations
and reductions in their strategic nuclear arsenals.
In addition, the discovery of the global effects of large-scale nuclear
war made nuclear war even more undesirable. Even if a country could
successfully disarm its enemy with a massive first strike of nuclear
weapons, that country itself would be seriously affected by many of
the global effects of the war; for example, by world-wide dispersal
of radiological products of nuclear explosions, by excessive ozone
consumption of nitrides generated in nuclear explosions, and by temperature
decreases caused by dust clouds. The realization of the serious consequences
of a nuclear war helped reverse the nuclear arms race between the
two superpowers.
In similar fashion, if US decision-makers understood the serious consequences
of a space war, they might turn to support cooperative approaches
in addressing security problems in space. This paper analyzes one
such consequence of space warfare by examining the change in the amount
of space debris generated by such a conflict.
The
current hazard of space debris
Satellites in space are
not safe even in the absence of war. There are many natural and artificial
objects moving through space around the earth that threaten satellites.
If a satellite collides with one of these objects, it could be seriously
damaged or destroyed; the damage would depend on the mass of the object
and its approach velocity. Typically, satellites suffer little or
no damage if hit by objects smaller than one centimeter (1 cm). Very
large objects in space, larger than ten centimeters (10 cm), are rare,
thus the probability of their colliding with a satellite is low and
can be ignored in normal estimates. Accordingly, the major concern
of debris collision is with medium-size objects of between 1 ~ 10
cm.
The total number of medium-size debris objects around the earth is
about 360,0005, of which 120,000 are
in Low-Earth Orbit (LEO) of altitudes below 3,000 kilometers (km),
170,000 are in Medium Earth Orbit (MEO) of altitudes between 3,000
km and 30,000 km, and 20,000 are in geostationary (or geosynchronous)
orbit (GEO) at an altitude of 36,000 km6
. Despite their numbers, these objects do not yet pose a serious threat
to space activities, as the risk of a satellite receiving destructive
hits of space debris is still very low. Table One shows the intervals
between two destructive debris impacts on a satellite with a size
of 100 square meters (m2). Given that collisions occur randomly, the
time between two impacts can vary widely. Table One provides the maximum,
minimum and mean of the possible time intervals between two hits in
three different Low Earth Orbits. It shows that a satellite of 100
m2 would receive one hit in a few hundreds years time in LEO. This
time is much longer than the operational life of most satellites,
which are usually on the order of a few years. Satellites in higher
orbits have less risk of a destructive collision because the debris
population density decreases as altitudes increase.
Table One, Time Between Debris (>1 cm) Impacts
on a Target Object
of 100 m2 Cross Sectional Area7
| Altitude |
– |
Time
(year) |
| 400
km |
mean |
1,214 |
| min |
776 |
| max |
1,674 |
| 800
km |
mean |
245 |
| min |
151 |
| max |
310 |
| 1,500
km |
mean |
534 |
| min |
323 |
| max |
698 |
Hazard
of Space Debris after a Space War
Although the number of
debris fragments around the earth is enormous, their total mass is
not that large; for example, the total mass of all the medium-size
debris is estimated to be around 2,000 kilograms (kg)8
. If we assume that the debris have a universal mass distribution
around the earth, the mass of debris is estimated as about 700 kilograms
in LEO, 1,000 kilograms in MEO, and 100 kilograms in GEO.
However, if an anti-satellite interceptor is destroyed in a war, it’s
debris could make a significant contribution to the overall total.
For example, a Soviet anti-satellite interceptor, Cosmos, has a mass
of 1,400 kilograms9 , which is twice
the current debris mass in LEO. If a Cosmos interceptor broke into
fragments with sizes of 1~10 cm in LEO, it could triple the population
density of the debris there. The new US anti-satellite interceptors
could be lighter, on the order of 100 kilograms, which is still not
negligible compared to the mass of existing debris. These interceptors,
if launched and exploded in a space battle, would significantly increase
the debris population and the risk to satellites orbiting the earth.
In addition to the interceptors themselves, those satellites targeted
by them will constitute another source of debris. If a two-ton satellite
is destroyed and broken into medium-size fragments in a space war,
it will double the whole debris population and accordingly double
the risk of an innocent satellite being hit by debris. Similarly,
a war involving hundreds satellites and interceptors could increase
the debris population by hundreds of times. Therefore, the interval
between two impacts to any particular satellite in LEO will be reduced
to less than one year. In other words, any satellite in LEO will likely
receive at least one hit every year. The result is that more and more
satellites in LEO that are intact when conflict begins will be damaged
or destroyed by debris even after the war ends, with the debris they
generate causing more and more debris that places even more satellites
at risk. A process of collisional cascading may set in (collisional
fragments trigger further collisions) and much more debris will be
generated. In short order, a “debris barrier” could
result that would prevent the stationing of any new satellites, or
other space activities, in Low Earth Orbit.
No matter who launches the war and whose satellites are destroyed
in the war, the result will be the same if a few hundred satellites
and anti-satellite interceptors are involved: all satellites in LEO
will eventually be destroyed and no new satellites can either be deployed
in, or transit through, LEO. The result is that no country will be
victorious in a space war as no country will be able to use space
for tens of years until most of the debris disappears. Such a scenario
would constitute a disaster for the entire international community.
Conclusions
and Discussions
Traditionally, zero-sum
assumptions have been used to analyze security issues. For example,
a few players try to divide a certain amount of wealth. If one player
can dominate the others through force, this player can then obtain
a larger fraction or even the whole wealth. This kind of zero-sum
thinking has historically been repeated in the competition for territory,
regions of control, markets, and so on, however, the zero-sum approach
is counter-productive under some circumstances, especially when the
object being sought is itself vulnerable to the competition for it.
Such cases, such as the benefits derived from the use of outer space,
call for a non-traditional security approach. As described above,
the space environment is very vulnerable to a war where debris multiplication
and the collisional effect place all space assets in a particular
orbit at risk. Even if a country that successfully destroys all the
satellites of its enemies will face the risk that its own satellites
will be destroyed after the war by mounting space debris.
While the above conclusion applies to all countries, it is especially
relevant for the US because of its dominant position in space and
its large number of space assets, both military and civilian. If the
space remains peaceful, it will continue to provide huge benefits
for Americans; the loss of such benefits for the US would be equally
consequential.
To maintain space as a peaceful environment, it is important to ban
weapons in space and the potential for any conflict in space. Accordingly,
proposals for preserving the non-weaponization of space are very much
in the US interest. Given America’s strong political influence,
its dominant position in space and in aerospace technologies, the
US is in a very favorable position to negotiate an agreement on the
non-weaponization of space. Compared to other arms control agreements,
an agreement on the non-weaponization of space would be easy to monitor
and verify. 10 US decision-makers should
not have to worry about evasions in implementing a space agreement,
as they do for other agreements, for example, the Biological Weapons
Convention.
To be sure, an agreement on the non-weaponization of space will also
benefit China. While limited compared to the US, China derives many
benefits from current uses of space. Similar to the US, however, China
would not be able to increase its use of space in the event of a war
in space. A ban on space weapons would relieve China’s concern
about conflict war in space and thus help shape China’s peaceful
development in space.
Most importantly, however, it is in the common interest of all peoples
of the world to ban weapons in space and the potential for space conflict.
*
Director of Arms Control Program, Institute of International Studies,
Tsinghua University, Beijing 100084, China. Tel: 86-10-62773391, 62788801;
Fax: 86-10-62773173; Email: libin@mail.tsinghua.edu.cn;
Website: http://learn.tsinghua.edu.cn/homepage/S00313/index.htm
Notes:
- United
States Department of Defense, "Secretary Rumsfeld Announces
Major National Security Space Management and Organizational Initiative,"
News Release, No. 201-01, May 8, 2001. internet version. http://www.defenselink.mil/news/May2001/b05082001_bt201-01.html.
- The
Boeing KE-ASAT factsheet. Available at http://www.boeing.com/defense-space/ic/keasat/
- United
States Department of Defense, "Secretary Rumsfeld Outlines
Space Initiatives," News Transcript, Tuesday, May 8, 2001 -
1:58 p.m. EDT. internet version. http://www.defenselink.mil/news/May2001/t05072001_t0508spa.html.
- Jenni
Rissanen, "CD Concludes First Part of 2001 Session Empty-Handed,"
Disarmament Diplomacy, internet version. http://www.acronym.org.uk/dd/dd55/55genev.htm.
- R.
Walker et al., “Update of the ESA Space Debris Mitigation Handbook,
Executive Summary,” July 2002. Ref: QINETIQ/KI/SPACE/CR021539.
ESA Contract 14471/00/D/HK. http://www.esa.int/gsp/completed/execsum00_N06.pdf.
p. 1.1.1.
- Ibid.
p. 1.2.2.
- Ibid.
p. 1.3.3.
- An
Jiaxin, “Progress in the Research on Space Debris (Kongjian
Suipian Yanjiu Jinzhan),” Guoji Taikong (in Chinese). pp.11-12.
- Encyclopedia
Astronautica, http://www.friends-partners.ru/partners/mwade/craft/i2p.htm.
- Du
Xiangwan et. al, "On Treaty of Space Non-Weaponization and
Its Verification", 41st Pugwash Conference on Science and World
Affairs, Sep 17-22, 1991, Beijing, China.
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