CCNet ESSAY, 21 December 2000




By Anatoly V. Zaitsev <>

Report of International Conference
September 23-27, 1996

Russian Federal Nuclear Center
All-Russian Research Institute of Technical Physics
Snezhinsk (Chelyabinsk-70)
Russia, 141400,

Tel.: (095) 575-5859
Moscow region, Khimki-2
FAX: (095) 573-2584
Leningradskoe shosse., 24

Lavochkin Association, Khimki, Moscow Region, Russia


Between a diversity of dangers, menacing to existence of a mankind, the
possible consequences of impacts of asteroids and comets with the Earth are
considered recently by a sufficiently serious manner. It became evidently,
that a collision with an object few kilometres of size could result
destruction, in fact, of all lives on our planet [1¸3].

However, a threat can be provided not only by large-scale objects, a
probability of collision with which is sufficiently low, but also relatively
small objects of the Tunguska meteorite type. This is due to the current
abundance of the Earth with potentially dangerous technogenous objects. It
refers to nuclear objects, chemical plants, toxic wastes storehouses, etc.
Destruction of any of them in the case of the asteroid impact can result not
only the human victims and hardware damages, but also became as a peculiar
"trigger" for development of the ecological crisis or nuclear conflict.

Increased understanding of degree of the danger of such developments and
their effect on the stable mankind development provides a necessity to take
measures in order to avoid such catastrophes or decrease damages from them.

Their necessity is confirmed by recently conducted studies and analyses
which showed, that the contemporary level of the technological development
of the word leading countries allows to proceed to creation of the Planetary
Defense System (PDS) aimed against the meteor and asteroid danger [4¸9].

Meanwhile, where are quite, and it is necessary to recognise, well-proven
thoughts, that the PDS could be used not only for the mankind rescue, but
also as a mean for destruction of entire countries and regions [10].

Whole our historical experience argues that this is quite possible. Perhaps
it is impossible to find neither technical human hands creature, which was
not harmful for him. Moreover, the scales of possible disasters in the case
of the PDS use for military purposes could not be compared with those we
have had in the past.

Taking into account particularities of above anxieties, this paper contains
an attempts to reveal some of potentially hazardous problems and
consequences of the PDS development. Moreover, the main reason, according to
which a main emphasis is laid mainly on the analysis of the negative
occurrences, is a necessity to develop measures with the aim of their

A number of possible scenarios was developed with this goal. Some of them
could be seemed as unreal or even absurd, referred to the fields, which
touched may be only by fantasist.

Nevertheless, such approach allows more clearly reveal the node problems of
the PDS development, formulate its maximum rigorous requirements and
development measures for their execution.

At last it will allow to provide the maximum reliability and efficiency of
the PDS as well as to remove or as much as possible to reduce a possibility
of negative consequences of its development and use.


At present the permanently operating service of the small celestial bodies
observation and tracking does not exists yet. Nevertheless, many of
observatories in the word perform such observations. So, thanks to a
progress, reached in the fields of the observation instruments development,
data recording and processing we can wait in the nearest future the sharp
increase of the number of asteroids and comets, approaching to the Earth
orbit and intersecting it.

Then, any object, moving to the Earth along the impact trajectory, can be
detected at any moment. Sizes of this object can be from tens and hundreds
meters to few kilometres. In the first case a catastrophe of the regional
scale can threat us, in the second one - the global catastrophe can happen
on the Earth.

It is obvious, that in the case of the in time warning on the danger, the
word community will take all possible measures in order to prevent the
catastrophe or reduce its possible damages.

However, a probability of the favourable for us outcome of events will
depend on the many factors combination, such as, for instance, trajectory
parameters and other characteristics of the threatening object, which
provides us with the time margin, necessary for organisation of
counter-measures, availability of sufficient number of the corresponding
technical means, etc.

Between a great number of factors, on which our destiny will depends, the
time factor is the most important. Clearly, that first of the most important
conditions, providing efficiency of taken measures, is in time, without any
delay warning on a danger.

In order to meet this requirement, it is necessary to provide not only
immediacy of data delivery, but also exclude any, even the most little
possible reasons, which can results data delaying, and, the more so, their
loss or hide. All reasons of this can be conditionally divided into
following two categories: technical and non-technical ones.

Technical reasons consist of different malfunctions and failures in the
communication systems due to both internal errors and external factors. They
combine the disaster relief and other natural phenomena, such as, for
instance, powerful solar flares, resulting malfunctions of the communication
systems and computer networks.

Non-technical reasons in a considerable degree are due to the so-called
"human factor". Only a man can intentionally or unintentionally delay, or
even hide the information. It can be due to the negligence or, on the
contrary, due to the excessive sense of responsibility. For example, a wish
can arise to re-verify acquired data. With that a possibility can't be
excluded to loss the valuable time to be spent to take necessary specific

We can't exclude numerous other cases, for instance an intentional hide of
data due to psychical and other illness, on the religious or some other
motifs. Simultaneous coincidence of many unfavourable circumstances is
possible as well.

Such assumption may seem as unreal or absurd. But we know a great number of
examples, when due to different fortuities, including these through a man
error, great tragedies and catastrophes took place. So, in the situations,
when a destiny of mankind or some of its part is to be decided, such
fortuities shall be excluded or minimised.

By this reason, prior the PDS creation, it is seems as necessary to develop
and accept, on the international level, a number of measures, providing
operational warning, as well as those excluding or minimising a probability
of delay, loss or hide of data on the dangerous celestial bodies. It will be
necessary to develop also a warning procedure and define a number of persons
and organisations, which must receive the necessary information and in which
sequence. Moreover, it will be necessary to think over procedure of the
Earth population or some individual countries warning as well.

Basing on above considerations, the first of the most important requirements
of the future PDS: along with reliable detection of the dangerous objects
the Ground/Space-Based Service of Observations (GSBSO) of the PDS, providing
a guaranteed in time delivery of the acquired data to the concerning persons
and agencies.

Evidently, in order to meet this requirement, it will be reasonable to use
an experience gained by a number of means of military destination: services
of control of the open space, warning on the rocket attack, etc. For
instance, the data acquired by the observational means could be delivered to
the centre of control of the open space (CCOS), and then directly delivered
to authorities of these and other countries.
For this purpose at the initial phase of the GSBSO deployment the Russian
CCOS of the Ministry of Defense and identical to it the US NORAD Centre
could be used.

It is obvious, that in parallel to or after the CCOS the data on detected
celestial bodies shall be delivered to the astronomy and other science

Moreover, it is important to provide guaranteed delivery of data to
authorities of states, on which territory, as per forecasting, the
relatively small asteroid should fall. This is necessary in order to exclude
a temptation to damage or even distract these countries by not announcing on
a danger.

In fact, it is necessary to note that an accurate prediction of the impact
point is hardly to provide due to its great spread because of bad knowledge
of the falling object's parameters, particularly aerodynamic ones [11].
Meanwhile, in some time development of the observational means will
contribute to execution of such prediction. So, it is necessary to take all
measures to exclude a possibility of hide, in some reasons, data on
dangerous asteroids.

Preliminary studies show that this requirement will be fulfilled more simply
and reliably with development of the GSBSO space segment. In this case it
will be relatively easy to provide an independent reception of data from the
space-borne observational means by ground-based reception stations in
different regions of the terrestrial globe. By the way, this is a weighty
argument in favour of development of space-borne observation means.

Besides of mentioned above, there is also a number of reasons to hide data
on asteroids, for instance for their utilisation in future for the military
purpose or as a source of raw material resources.

During process of the celestial objects observation, such relatively small
objects can be detected, that, at corresponding correction of their orbits,
could be used to strike territories of different countries.

As it was discussed above, in the nearest future such operation could be
fulfilled. And it is not obligatory to use the PDS means for this purpose.

It will be sufficient to study well the characteristics of the celestial
body during execution of usual space missions and then to push it, using any
known method, to the Earth impact trajectory, For this aim, in some
favourable cases, it may be appear, that it is sufficient to use even the
Spacecraft (S/C) propulsion system, or the impulse of this S/C collision
with the asteroid. In perspective the "Space Billiards" method [12] could be
used, that will allow to change the trajectory of sufficiently great body
due to the process of consecutive collisions with smaller objects.

So, a possibility can not be excluded to use the S/C, including those of a
science destination, as a mean for deflection of asteroids in order to
distract targets on the Earth. Apparently, in order to exclude such actions,
it will be necessary to accept certain restrictions on some active
operations in missions of the interplanetary S/C to small celestial bodies.
Correspondingly, similar restrictions must be imposed on rocket/space means
of the PDS, that will allow to fulfil a requirement of impossibility of its
military use.

In order to meet this constraint, the available great experience of the
international control of arms could be used, that will provide a confidence
in a possibility of solution of this problem. It is necessary also to take
into account the fact, that at present asteroids are studied in the quality
of sources of the raw materials for our future generation.
So that a temptation can appear to hide data on asteroids, potentially
suitable for this purpose, in order, for example, to monopolise the property
rights of these resources. To avoid such situation, it is necessary to
establish procedures, regulating problems of investigation and utilisation
of these bodies resources.

Discussed above problems of the data provision, have one important aspect.
The question is, that after receiving of data on the potential danger,
together with necessity to take effective measures to prevent a catastrophe,
a dilemma will inevitably arise before the states authorities: is it
necessary to notify the Earth population about this fact or not?

This problem is represented as more complicated, then that of operational
warning of competent persons and agencies, which, in higher degree has the
organisational/technical character.

But an "announcement dilemma" touches an enormous complex of moral, ethic,
religious and other problems, discussion of which is far outside of the
framework of this paper and author's competence.

May be it would be more reasonable, after corresponding studying of this
problem by experts and its wide public discussion, to accept an
international law or code of reglamentations for these critical situations,
if, certainly, these documents were not developed yet. They will have to
regulate behaviour of all persons, touching this problem: from the first
discoverer to state authorities, coming to a decision on a danger removing
and population warning.

Certainly, at the PDS development it will be necessary to solve a variety of
more individual, but not less important problems, then those discussed
above. Particularly, it will require to increase the number of allowable
azimuths of launch of the launch vehicles, using for launching of means of
interception of dangerous celestial bodies, to provide the launch safety of
launch and using of the nuclear means of destruction, to remove or minimise
a possibility of damage by fragments of the destroyed object, etc. However
restricted limits of this paper do not allow to carry out even simplified
analysis of these problems.


In the case of accepting of effective measures, one can hope, that problems
of guaranteed provision of data and no using of the PDS in the military
purposes can be solved.

Nevertheless, not at the phase of the PDS development and deployment, but
and after it, a number of extremely complicated problems can arise, if
measures for their prevention will not be undertaken in advance. The essence
of one of them is the fact, that a possibility can't be excluded, that for
some reasons, the PPS "owner", can refuse from its using for protection of
some state or group of states. That is, a wish can arise to use this
situation to exert a pressure to these countries in order to change a
Geo-political situation, etc., or even to destroy them.

A refuse can be expressed both in the evident and implicit form. In the
first case it can be motivated, for instance, by a fact, that there is a
danger, that the fragments of the destroyed celestial body could reach
territories of states, which would not be suffered, if the PPS is not under
use. In the second case, for instance, a feign of malfunction of the
intercepting devices, miss at interception, etc. can be used. Data hiding is
also possible, that it was discussed above. Hence, one more requirement to
the PDS is as follows: guaranteed defense of any country.

It is becomes clear from above examples, that unusing of the PDS in the
critic situation can provide not lower threat, than its direct using with
the military purpose. So, excluding  the dilemma: to use or not to use the
PDS means of defense, can appear as one of the most important and, may be
the most complicated problem, associated with the Earth protection against
the asteroid danger.

Solution of "dilemma of the PDS unusing" will require development of wide
set of measures, and it is possible, that the first of such measures can be
adoption of the international treaty, forbidding development and monopoly
possession with the PDS by one state or group of states, united in single
military/political block or identical to it.

It seems, that one of the most acceptable options of this dilemma solution
could be development of the PDS simultaneously in Russia and USA, which
have, in fact, all necessary basic means or their prototypes for development
of such system. In this case the combined GSBSO and autonomous interception
services could be created.

Development of the combined GSBSO, which could include the observation
facilities of other countries, would allow to provide execution of the first
its requirement: guaranteed operational delivery of the acquired data to
corresponding authorities and agencies, as well as to exclude a possibility
of data hide.

At the same time, creation of the autonomous interception services on the
basis of the national rocket/space, nuclear and other means of Russia and
USA would allow to eliminate or considerably reduce risk of the PDS unusing.
Moreover, it would even increase the PPS reliability due to the functioning
of means, based on different principles and by some other reasons as well.

It is obvious, that an "unusing dilemma" can arise only in the case of
collision with the relatively small asteroid. In the case of the global
catastrophe the Humanity will combine its efforts for struggle against a
common danger.

However, the mankind's capacities on warding off of the threat from the
Space will never be unlimited. A situation can be, when we will not evade
from the global catastrophe.

Perhaps, in this case the single alternative to general destruction could be
an option of using of the lunar base for saving of small colony of
terrestrial people. After decay of the catastrophic events on the Earth,
they could come back and again populate the Earth.

Thus, numerous arguments in favour of the space programs development,
including the Moon colonisation, can be added by one more: as margin the
mankind must have the "Noah's Ark - 2".

It is necessary to note, that not only a possibility of perish of whole
mankind, but also and its part compel us to reflect on a possibility to keep
some minimum of spiritual and material valuables, which would allow to
regenerate and restore losses at any possible catastrophes of the regional
and global scale.

With this aim it would require to develop and execute a special program,
which could be named as "Phoenix", including a wide range of measures of
fulfilment of such objective. Apropos, may be some kind things were in
history, that could explain an extremely high level of development of some
of ancient civilisations.

The analysis, performed in this work concerning some negative of scenarios
of possible events, has no for its aim to force a horror around the asteroid
danger problem or to find guilty of somebody in evil intentions. As it was
discussed at the beginning of paper, it was done with the objective to
formulate more well-proven requirements, imposed on the PDS. Fulfilment of
these requirements will allow to exclude a possibility of realisation of all
considered (and more and more number of not considered) negative options of
the events development, leaving them for using as scenarios in the science
fictions, movies, etc.


Results of the executed analysis of possible problems and consequences of
the PDS development allow to formulate a number of the most important
general requirements which the PPS shall satisfy.

Besides of the obvious requirement of non-admission of the PDS use with a
military purpose, the PDS shall satisfy, at least, to two more the most
important requirements: guaranteed in time warning on a danger, as well as
to guarantee the defense of any country against this danger.

It is clear, that during the PDS development, deployment and operation it
will be necessary also to satisfy to numerous partial constraints, including
those mentioned in this paper. In order to meet some of them in the nearest
future, it would be reasonable to take the following measures on the
international level:

1. To take measures excluding possibilities of the loss, delay or hide of
the data both on threatening celestial bodies, and those, which represent an
interest as row materials resources.

2. To develop a procedure of warning as well as to define a number of
persons and agencies, to which the data shall be delivered and in which

3. To adopt the code of rules of behaviour for persons, receiving the data
on a danger, as well as the warning procedure for the Earth population.

4. To initiate an issue concerning creation of the international lunar base
and to develop procedures, allowing regenerate or restore possible losses as
a result of catastrophes of the regional or global scale.

5. To restrict active experiments with small celestial bodies. In order to
exclude a possibly of the monopoly possession by the PDS, it seems as
reasonable to accept an international agreement on non-deployment of the PDS
by one or few countries, united in single military/political block.

Undoubtedly, the more detailed study of problems, concerning protection
against the asteroid and cometary danger, will allow to reveal more numerous
other problems of the most various character. But even from above list is
becomes clear, that the PDS deployment will put for the mankind a number of
essentially non-ordinary problems, each of them may be not only from the
point of view of the science/engineering, but also from points of view of
organisation, politics, law, moral, ethics, etc.

Possibility of their solution has no doubts. Nevertheless, this will require
to combine efforts of a great number of experts in the field not only of the
natural sciences, but also and humanity sciences. As a result, works on the
PDS development can became as  a peculiar catalyst of development for many
industries and technologies, as it was at development of such great
projects, as for instance, space ones, that will favour not only the
defense, but also development and unity of the Humanity.


1. Smith Joseph V. - Protection of the human rase against natural hazards
(asteroides, ñomets, volcanoes, earthquakes// Geology, v. 13, p. 675-678,
Oct. 1985.  

2. The Spaceguard Survey: Report of the NASA International Near-Earth-Object
Detection Workshop// Edited by D. Morrison. JPL/CIT, Pasadena, CA, Jan. 25,

3. Gehrels T. - Collisions with Comets and Asteroids// Scientific American,
p.54-59, March, 1996.

4. Zaitsev A. V. - Proposals on development of the System of prevention of
the Earth collision with asteroids and comets (re-orientation of works
carrying out in the framework of the SDI into peaceful objectives)// Report
to the General Secretary of the Central Committee of the Communist Party of
the Soviet Union, N 629203 from 20.10.86, Babakin SRC, 17 pp., 1986.

5. Zaitsev A. V. - Some principles of construction of the system of
prevention of the Earth collision with asteroids and comets// Proceedings of
23-th readings of K.E. Tsiolkovsky. Section: Problems of the rocket/space
technology. Moscow. IHST of AS of the USSR, p. 141 - 147, 1989.

6. Kovtunenko V. M., Zaitsev A. V., Kotin V. A. - Scientific and Technical
Aspects and Problems in Building the System to Protect the Earth Against
Hazardous Space Objects// Report of International Conference "SPE-94",
Snezhinsk, Sept. 26-30, 1994.

7. Wood L., Hyde R., Ishikawa M., Ledebuhr A. - Cosmic Bombardment IV:
Averting Catastrophe In The Here-And-Now// LLNL Doc. No PHYS.BRIEF 94-029.
International Conference "SPE-94", Snezhinsk, Sept. 26-30, 1994.

8. Kovtunenko V. M., Zaitsev A. V. - Protecting Earth from Asteroid Hazards
is a Real Task for the World Space States// Space Bulletin, vol.2, N4, pp.
25-27, 1995.

9. Zaitsev A. V. - Possible Appearance and Stages of the Planetary
Protection System Creation// Report of International Conference "SPE-96",
Snezhinsk, Sept. 23-27, 1996.

10. Foley T. - Sagan Backs Inventory// Space News, Okt. 10-16, 1994, p.17.

11. Deryugin V. A., Zaitsev A. V., Kozlov I. A. - Assessments of Possible
Scattering of Celestial Bodies Fall Places on the Earth Surface// Report of
International Conference "SPE-96", Snezhinsk, Sept. 23-27, 1996.

12. Zaitsev A. V. - Assessments of Limiting Possibilities for Some Methods
of Action on Asteroids ahd Comets// Report of International Conference
"SPE-96", Snezhinsk, Sept. 23-27, 1996.




Report of International Conference
September 23-27, 1996

Russian Federal Nuclear Centre
All-Russian Research Institute of Technical Physics
Snezhinsk (Chelyabinsk-70)
Russia, 141400,
Tel.: (095) 575-5859
FAX: (095) 573-2584
Moscow region, Khimki-2
Leningradskoe shosse., 24


Lavochkin Association, Khimky, Moscow Region


In fact at present there is no doubt about the existence of real danger
originated from the asteroids and comets impacts with the Earth, that
threatens its biosphere, so this circumstance does not require additional

Earlier conducted works [1-4] show that the up-to-date levels of development
of technologies allow to proceed already to the practical realization of
measures, providing the protection against this danger.

This work develops and adds some conditions related to the earlier proposed
principles of construction of the Planetary Defense System (PDS) aimed to
protect against asteroids and comets. Use of the term «planetary» in the
name is explained by the fact, that this system will be used to defend not
only of the Earth, but also other bodies of the Solar System, and the Moon
in the first place. It will be necessary not only for protection of the
lunar colonies, but for preventing of the consequences of the great bodies
impacts with the Moon, that are probably unfavourable for the Earth's
population. For instance, a possibility of the great fragments falling on to
the Earth, pollution of the near-terrestrial space, change of the Moon's
orbit could be referred to these effects.

The approach to the PDS architecture, which is proposed below, is based on
the utilization of already existing, mainly rocket/space technologies.
Obviously, that with the appearance of new science and technology
achievements, the PDS and means of configurations used will be essentially
upgraded and the System will have more capacity for the defense against such
space danger.


As it was shown in earlier works, in order to protect the Earth effectively,
and in future - other celestial bodies, the PDS must include the following
three interconnected elements [1-3]:

· Ground/Space-Based Service of Observation (GSBSO);
· Ground/Space-Based Service of Interception (GSBSI);
· Ground-Based Control Center (GBCC).

It is obviously, that the PDS shall provide protection both from the
celestial bodies, which will be detected several days before the collision
with the Earth, and from the those, impact with which can be predicted many
years in advance. Therefore the PDS shall have at least two ranges of the
target detection and interception: the operational one and stand-off one

But, taking into account a rarity of impacts with the Earth of the even
relatively small asteroids (about once per century), it appears unreasonable
to develop all the PDS means and maintain them in the state of the permanent
operational readiness (as in the cases of the anti-air and anti-missile
defenses), at least in the nearest future. More rational would be such
approach to the PDS configuration, when most of its components are based on
the facilities of the «double» utilization and/or are combined with the
components of the systems and facilities of another destination.

It will allow to maintain some of the PDS elements in the operational mode,
which conditionally could be named as «virtual» one. This implies that a
number of the PDS components will not be included in its composition.
However, in case of the critical situation, they must be promptly developed
or involved from other systems or services for fulfillment of the PDS tasks.
Of course, once in the «virtual» mode, the System will not be able to
fulfill its functions completely. Therefore, the GSBSO facilities
permanently under the action must be created, which would provide the
constant monitoring of the outer space, and the necessary minimum of the
means, providing the operational counter-measures against danger, must be
deployed as well. At the same time the stand-off interception could be quite
well kept in the mode, close to the virtual one.
So that, it is clear that the use of «virtualization» principle will allow
to decrease considerably expenses and delays of the PDS deployment.

Many other constraints must be taken into account at the PDS development and
deployment, which follow from its specificity. The following can be noted
from the most important factors [8]:

· provision of the guaranteed operational warning of the danger of a
small celestial body impact;
· provision of the guaranteed use of the PDS means for any country
territory protection against falling celestial body.

In order to fulfill the first requirements, the combined international GSBSO
could be developed, which would exclude the possible losses, delaying or
hiding of the data on the celestial bodies both threatening to  the Earth
and representing an interest to somebody from the point of view of their
utilization in the future with the aim of the Earth bombardment by asteroids
or the asteroids utilization as the sources of the raw materials. The most
simple and reliable method of these tasks fulfillment could be provision of
the simultaneous and independent receiving of the data from the space
segment of the observation service, arranged at different points of the

In order to satisfy the second requirement, it is necessary to create
several autonomous GSBSI segments on the basis of the missile/space, nuclear
and other facilities of Russia, USA and possibly of some other states,
possessing identical means. It would allow to exclude the potential cases of
the PDS non-use for defense of any state for political, technological or
some other reasons. Sure, that the feasibility of these and other
requirements represents a sufficiently complicated problem. Nevertheless,
the experience of development of the complicated rocket/spatial, combat and
other systems provides the confidence in possibility of their fulfillment.

Let us consider the possible configurations of the PDS architecture.


Necessity of the reliable detection of the dangerous celestial bodies
suggests for the GSBSO, and particularly for its Space Observational Segment
(SOS), a great number of complicated requirements for the outer space
permanent monitoring, value of range of the target detection, efficacy,
accuracy of determination of the celestial bodies trajectories and other
parameters. The analysis of some of these requirements, from the point of
view of principal possibility of their fulfillment at the state-of-the-art
level of the optics/electronics development, was done in the works
[5,7,9,10].  One can also find there the ground for necessity of the SOS
development and possible configurations of its construction.

Below we will discuss one of possible options of the operational SOS
construction, destined, in the first place, for detection of small celestial
bodies in the nearest proximity to the Earth (at the distances up to few
tens of millions of kilometers).

The analyses of the family of possible trajectories of asteroids, moving
along the Earth impact orbits, were carried out for determination of the
areas, to be tracked by the SOS facilities. With that it was taken into
account, that their perihelia and aphelia lay correspondingly in the limits
of 0.1-1 and 1-6 A.U. Inclinations of their orbits to the ecliptic plane are
from 0o to 90o.

Some of the results of simulation of these bodies' motions relative to the
Earth are given in Fig. 1, where, for clarity, only trajectories are shown,
laying in the ecliptic plane. This picture will be practically identical for
inclined trajectories. Two closed curves show regions, which limits
correspond to the time of approaching to the Earth not less than from 3 to 5
days. It is necessary to note, that these frontiers correspond to the
so-called fast asteroids with low aphelion and high perihelion, i.e. with
orbits having eccentricities close to 1. The approach time of asteroids with
low eccentricities from these frontiers will be considerably more.

In order to provide these regions tracking, it is considered reasonable to
put the Spacecraft (S/C), equipped with a telescope, to the orbit,
coinciding with the Earth orbit, but with some lag or advance relative to
it. With that, during the celestial bodies observations it is possible to
provide the sufficiently acceptable phase angles, and what is very
important, that checked area will have relatively small angular sizes. For
instance, from the distance of 13 million km the 3-day region will be seen
under angle of about 60o. Thus, the checked area of celestial sphere will be
decreased nearly by an order in comparison with observations from the Earth,
for which it is necessary to keep under the control the whole celestial
sphere. In addition, the proposed option of the S/C location provides the
conditions good enough for observing the asteroids, approaching the Earth
from the Sun side. It is impossible to observe such asteroids from the Earth
at all.

Conducted analyses [10] show, that using already existing optic/electronic
observational facilities, scanning of the area under consideration is
possible with the interval of several hours, that is quite sufficient for
the operational warning of a danger. Few S/C can be deployed for the
efficient monitoring of this area. Their heliocentric orbits can be arranged
in such a way, that they will revolve around the Earth at the distance of
10-20 million km, providing observation of the monitoring area under
different aspect angles.

Development of the proposed option is possible to begin as early as in
nearest future, by observing from the Earth regions, located in its orbit
along its motion path at the distance of 10-20 mln km. In this case all
necessary initial data for the S/C and its telescope will be acquired and
statistical data on asteroids, intersecting the Earth orbit, will be
The proposed method can be used in order to provide the global, widespread
ground-based observations of the space region, lying along the Earth orbit.
If confine oneself to the observation angles relative to the Sun more than ±
45o, in this case it will be possible to observe from the Earth the toreidal
region along its orbit with cross-section of few millions of km and length
of about 500 million km, i.e. on half of the Earth orbit. In this case, the
distant regions with small angular sizes can be observed with the majority
of the greatest astronomic instruments, such as BTA (Zelenchuk), Palomar
telescope, etc. and even by the Space Hubble S/C. It will be possible to
observe the nearer regions, using the smaller telescopes, but with larger
fields of view.

The realization of such international program, which conditionally can be
named as «Tore», would allow considerably increase the efficiency of
detection of asteroids, intersecting the Earth orbit, specify the degree of
the asteroid danger and better reasonably formulate the SOS requirements.

Then the S/C with telescopes could be injected in to the regions of the
Earth orbit at angles of about ± 90o relatively to the Sun-Earth direction,
which will provide an observation from the Earth of its orbit portions,
invisible from the Earth. Thus, the whole space region along the Earth orbit
will be monitored, that will allow to provide the early warning of the
overwhelming majority of the bodies, intersecting the Earth orbit.

In this case it will be possible to combine the problem of detection of
asteroids, intersecting the Earth orbit, with observations of the Sun side,
invisible from the Earth, that represents an essential interest for
forecasting of its activity. Such combination of objectives would be
reasonable, for instance, in the framework of GEKATA, SPINS, etc. projects
Realization of the «Tore» program must be considered as the first step in
the GSBSO development. Then, as the technical facilities are upgraded, it
will be necessary to provide the global monitoring of the whole celestial
sphere in order to exclude the possibility of unexpected appearance of the
hazardous celestial body with great orbital period, or, for example, for the
case of possible change of trajectories of celestial bodies, which did not
early threaten to the Earth. It would be due to the gravitational
perturbations at the planet's fly-by or as a result of collision with other
small celestial bodies.


Depending on the above-mentioned principles of the PDS construction, the
GSBSI will be based on the rocket/space facilities: Launch Vehicles (LV),
S/C, ground-based infrastructure (Space Launch Sites, telecommunication,
guidance and control facilities, etc.). Because of many reasons, for the
time being it is unreasonable to arrange in the space the facilities,
destined for provision of the counter-measures against asteroid danger

Between of all the variety of the available LV, the requirements for the
delay of preparation for the launch, payload mass, etc.  are mostly
satisfied to the LV «Conversion» (on the basis of SS-18 ICBM), «Zenit» and
«Proton». Especially the «Zenit» LV can be marked out, which, at
sufficiently large payload injected capability (12 tons in the parking
orbit), has unique performance related to the immediacy of launch. After
erection on to the launch table, it can be prepared for launch in 1.5 hour,
and the next launch from the same table can be executed in 5 hours [13].
Neither launch facility with the rocket in the word has such a capability.
Such performance makes this LV irreplaceable for the service of the
effective interception.

The rocket/space industry has also a number of the flight-proven Spacecraft
and advanced projects, which could be a base for development of the
S/C-reconnaissance and S/C-interceptor. To this type of S/C could belong
Spacecraft developed by Lavochkin Association, such as Mars-96 (Phobos)
series, SKIPPER space-bus, Orbital Module for the Mars-2001 mission, etc.

It is evident, that the nuclear industry has in its disposal many nuclear
warheads, which can be used as means, effecting the small celestial bodies.
It is necessary to note that with all the variety of possible means,
affecting on the celestial bodies, we shall not apparently have an
alternative to the nuclear means in the nearest future.

Let us consider an option of the effective intercept conception, basing upon
the approaches, stated in this and proceeding works [6,7].

Let us take one of the most critical options as an initial precondition,
when the time-period from the moment of the asteroid detection up to its
impact with the Earth does not exceed 3 days. Let us assume that the
asteroid's velocity is equal to 50 km/s, which is evidently close to the
extreme velocities of such objects.

The events can be in progress in the following sequence (Fig.2).

·  T = 0. Asteroid detection. Warning. Beginning of preparation of the
rocket/space facilities to the launch. Involvement of the additional
observation facilities. Updating of the asteroid parameters. Making
a decision on the S/C launch.
·  T » 12 hours. First intercept S/C launch.
·  T » 18 hours. First reconnaissance S/C launch.
·  T » 24 hours. Second (reserve) reconnaissance S/C launch.
·  T » 48 hours. Second (reserve) intercept S/C launch.

It is clear, that such rate of launches can be provided only at the
conditions of a number of possible LV launch azimuths or at launches from
different Space Launch Sites.

The first intercept S/C is launched with the aim to encounter the asteroid
at a maximum distance from the Earth. The reconnaissance S/C, due to its
small mass, will be accelerated up to considerably greater velocity and, by
outstripping the first S/C, it will be the first, who meets the asteroid.

On the basis of the data acquired from these S/C, the Space Flight Control
Center (SFCC) generates the model of this body, that is utilized for
preparation of all necessary data, which are to be transmitted on-board of
the intercept S/C. All these operations last about 8 hours. Then the
intercept S/C performs the maneuver of approaching to the asteroid. At their
collision the nuclear warhead is exploded and the asteroid is distracted or
deflected from the Earth impact trajectory.

Some time prior the collision, two small observational S/C must be separated
from the intercept S/C with the task to observe the results of the executed
operation from the safe distance. In the case of miss or necessity of
additional effect on the asteroid, the second intercept S/C will be used.

At using the «Zenit» LV for launch of the intercept S/C along the
energetically optimum trajectory, the mass of the warhead, to be delivered
to the asteroid, can reach 1500 kg. Power of such warhead is at least 1.5
Megatons [14], which will allow distracting the asteroid about 100 m in
diameter [15].

Identical sequence of events can be used for execution of the operations of
the long-range GSBSI. In this case the «Proton» Launcher will provide the

It is necessary to note, that for interception at the distant frontiers
outside the Mars orbit and inside the Venus orbit, as well as far from the
ecliptic plane - it will be necessary to use the S/C, equipped by the solar
or nuclear electrical/rocket propulsion subsystems.

Of course, this picture is fairly schematic. Its realization requires
solving a number of problems. However they do not grow out of the
capabilities of the current technologies.
Development of the main components of the operational PDS can be carried out
in the nearest future in the frameworks of the «Discovery» experiment [16]
and «Space Patrol» Project [17,18], during investigation of the asteroids,
flying near the Earth.

Besides the usage of the national rocket/space facilities, in the framework
of the international «Synthesis» Project it is looks like reasonable to
develop the versatile reconnaissance and intercept S/C on the basis of the
best world space technologies, taking into account the possibility of their
launches by the different Launchers, provision of telecommunication with
them, their guidance control, etc. Their development could be done in the
framework of the international space missions, for example to the small
bodies of the Solar System. Provision of small reserve of such S/C will
allow to use them, for instance, for the urgent mission to the suddenly
appearing objects of the type of comets Hale-Bopp, Hyakutake, etc.

Simultaneously with execution of the above works, the PDS ground control
segment will be developed and deployed.


Presented here brief exposition of the approaches to the Planetary Defense
System architecture, not pretending to the completeness of enveloping of the
whole problem issues, nevertheless shows the reality of the PDS development
on the basis of the up-to-date technologies.

Basing on necessity to meet a number of the most important PDS requirements,
it is necessary to accept that it must include the joint international
GSBSO, which primary components must be represented by the S/C, equipped by
the telescopes and injected into the orbit, coinciding with the Earth orbit,
at the distance of 10 - 20 million kilometers from it, as well as several
autonomous GSBSI segments on the basis of the national rocket/space, nuclear
etc. means of Russia, USA and, perhaps, of some other countries.

Development of these main components can be done in the nearest future in
the framework of the «Tore», «Discovery», «Space Patrol» and «Synthesis»
Projects. At that all these projects can be executed in the framework of
realization of the national and international programs of the outer space
exploration, i.e. they will became the key components of these programs. So
that, to the beginning of the third millennium it will be possible to carry
out the developmental tests of all PDS components and, thereby, to lay the
foundation for its deployment.

The author expresses his deep gratitude to A. V. Dobrov and I. M. Morskoy
for assistance and advises in writing this paper.


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Copyright 2000, Anatoly V. Zaitsev <>

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