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CCNet 22/2001 - 7 February 2001: PLANETARY DEFENSE SPECIAL
----------------------------------------------------------


"If a km-sized NEO is a "rubble pile," it is not impossible to
change its orbit by explosive mitigation systems: many low energetic
explosions could be used instead of one big explosion, e.g. dividing
a 20 Mt impulse into 20 impulses of 1 Mt each. This has to be analysed
separately and also applies for impactors. NEO mining is the next logical
step in space exploration which should be prepared using the
experience from Planetary Defense studies and tests (and hopefully not
from an emergency mission)."
--Christian Gritzner, Technische Universitaet Dresden, 6
February 2001


"Even for the most difficult cases such as the large-scale impacts
like the K/T or Permian/Triassic ones, there are, in principle,
realistic opportunities to prevent the impacts if they are of cometary
nature. After all, we are currently creating and developing the
scientific and technological basis for future generations. Their
opportunities will be much better, based on the results we can provide
them and on all the new discoveries they'll have fortune to open. But
facing the problem of civilization survival, each generation should
approach it as their own responsibility, because the next impact might be
the final event not only for this generation but for civilization as a
whole. It is also our obligation for past, present and future
generations."
--Vadim Simonenko, Russian Federal Nuclear Center, 6
February 2001



(1) TITANIC COLLISION SEEN IN DISTANT UNIVERSE
    EurekAlert, 6 February 2001

(2) PLANETARY DEFENSE AGAINST RUBBLE PILES
    Christian Gritzner <christian.gritzner@mailbox.tu-dresden.de>

(3) VADIM SIMONENKO ON COSMIC IMPACTS & IMPACT PREVENTION
    Vadim A. Simonenko <sva@sva.ch70.chel.su>

(4) AN IMPROVED ENGLISH TRANSLATION OF A RUSSIAN VIEW ON THE IMPACT HAZARD &
PLANETARY DEFENSE
    Anatoly V. Zaitsev <zav@berc.rssi.ru>

(5) FAO GERMAN/AUSTRIAN CCNet SUBSCRIBERS: METEORITEN-FRUEWARNSYSTEM
   (EARLY WARNING SYSTEM FOR METEORITES)
    Daniel Fischer <dfischer@astro.uni-bonn.de>


==============
(1) TITANIC COLLISION SEEN IN DISTANT UNIVERSE

From EurekAlert, 6 February 2001
http://www.eurekalert.org/releases/ca-tcs020601.html

FOR IMMEDIATE RELEASE: 6 FEBRUARY 2001
Contact: Ms Melanie Johnston-Hollitt
mjohnsto@physics.adelaide.edu.au
61-2-9372-4251
CSIRO Australia

Titanic collision seen in distant universe

A student astronomer has discovered evidence of a vast collision between two
giant clusters of galaxies.

Using the Commonwealth Scientific and Industrial Research Organisation's
(CSIRO) Australia Telescope, PhD student Melanie Johnston-Hollitt of the
University of Adelaide has found 'wreckage' indicating that two giant
clusters of galaxies have collided and merged.

The finding changes astronomers' views of how clusters and individual
galaxies evolve.

"Space is big. The chance of things running into each other is small," says
Professor Ron Ekers, Director of the Australia Telescope National Facility.
"Until now there has been only weak evidence that clusters might collide."

Such collisions may also create ultra-high-energy cosmic rays, the origin of
which has been a mystery.

The research will be discussed today [Tuesday 6 Feb] at a workshop on galaxy
clusters at the Australia Telescope National Facility headquarters in
Sydney.

Clusters are big groups of galaxies, all held huddled together by gravity.
Ms Johnston-Hollitt has been studying a cluster of about 500 galaxies called
Abell 3667, which lies 700 million light-years away [at a redshift of
0.055].

Abell 3667 appears to be a large cluster that has run into a slightly
smaller one. The key evidence is a pair of arcs of radio emission that
straddle the cluster, 12 million light-years apart. (On the sky, the
distance between them is about twice the diameter of the Moon.)

The collision and its aftermath are like "the Titanic hitting an iceberg,"
says Ms Johnston-Hollitt. "Afterwards you see only ripples and bits of
wreckage, but that's enough to show that there's been a collision."

Radio arcs of the kind seen in this cluster are very rare. The first ones
found were thought to be ghostly remains of dead, dissipated galaxies, and
were dubbed 'relics', Ms Johnson-Hollitt explains.

Professor Ron Ekers is one of the people who worked on the first known
examples of these objects. "It's very satisfying to see that these are
markers of important dynamic processes," he says, "not the Cheshire-cat
grins of dying galaxies."

Theorists had predicted that galaxy clusters would free-fall together at
thousands of kilometres a second, smacking into each other and producing
huge shock waves in the thin hot gas that fills the space between the
galaxies.

In 1999 researcher Kurt Roettiger, then of University of Missouri-Columbia,
and colleagues demonstrated that the shock waves would produce large arcs of
radio-emitting particles on the outskirts of the cluster, like those of
Abell 3667.

Cluster collisions release the largest amount of energy in a single event
since the Big Bang [1057 joules].

They might explain one of the outstanding mysteries in astronomy: the origin
of ultra-high-energy cosmic rays [1015 -1021 eV], which amazed astronomers
and physicists when first detected on Earth. "No process in our Galaxy can
make them," says cosmic ray researcher Dr Roger Clay of the University of
Adelaide, one of Ms Johnston-Hollitt's thesis supervisors. "Perhaps shock
waves in merging clusters power them up."

The radio arcs in Abell 3667 were first detected with the Molonglo
Observatory Synthesis Telescope (MOST) of the University of Sydney. "MOST is
an excellent instrument for finding these objects because they emit strongly
at the longer wavelengths that MOST works at," says Dr Richard Hunstead of
the University of Sydney, another of Ms Johnston-Hollitt's thesis
supervisors.

But imaging the arcs in detail required the power of the Australia
Telescope. "They are big on the sky but extremely faint," Ms
Johnston-Hollitt says. "The Australia Telescope is very sensitive to faint
objects and can make wide field images by 'mosaicing' together many smaller
views."

"The Australia Telescope picture is the first high-resolution image of such
a radio structure. It shows stringy filaments of radio emission that have
never been seen before in this kind of source, and which no-one has been
able to explain."

Ms Johnson-Hollitt has presented her research at several international
meetings, including last year's General Assembly of the International
Astronomical Union, astronomy's equivalent of the Olympics

Copyright 2001, EurekAlert

=============
(2) PLANETARY DEFENSE AGAINST RUBBLE PILES

From Christian Gritzner <christian.gritzner@mailbox.tu-dresden.de>

Dear Benny,

just some remarks on the comment by Mark Sonter on Planetary Defense!

If a km-sized NEO is a "rubble pile," it is not impossible to change its
orbit by explosive mitigation systems: many low energetic explosions could
be used instead of one big explosion, e.g. dividing a 20 Mt impulse into 20
impulses of 1 Mt each. This has to be analysed
separately and also applies for impactors.

NEO mining is the next logical step in space exploration which should be
prepared using the experience from Planetary Defense studies and tests (and
hopefully not from an emergency mission). NEO mining could also allow some
mitigation systems to operate efficiently: using conventional propulsion
systems as the Space Shuttle Main Engine (SSME) requires several 1000 tons
of LOX/LH2 for deflecting a 1 km NEO within some decades. Transporting this
amount of fuel from Earth to the NEO is nearly impossible using current
launch systems. If we could extract the
fuel from cometary water ice in these large amounts this system could become
an alternative to nuclear explosives. Such a system is very complex today,
but it could become a cheap and reliable solution in some decades.

A hot water rocket (which is more efficient than a steam rocket) needs about
10 times more fuel for the same impulse than the SSME, but no electrolysis
is needed in fuel production. I am sceptical that mass drivers would be a
good solution because they would consume a large part of the NEO as "fuel"
leading to large amounts of "Deep Space Debris" in the kg-range!  A more
promising option would be a solar mirror as proposed by Jay Melosh. But more
knowledge about the NEO surface material would be required for this method,
which also calls for NEO exploration and exploitation.

Best wishes,
Christian Gritzner

Technische Universitaet Dresden
Institut fuer Luft- und Raumfahrttechnik
Dr.-Ing. Christian Gritzner, Senior Engineer
01062 Dresden, Germany
Tel.: +49-351-463-8234 (Fax: -8126)
E-mail: christian.gritzner@mailbox.tu-dresden.de
Homepage: www.tu-dresden.de/mw/ilr/space/space.htm

===============
(3) VADIM SIMONENKO ON COSMIC IMPACTS & IMPACT PREVENTION

From Vadim A. Simonenko <sva@sva.ch70.chel.su>

Dear Dr. Peiser,

I'll try to answer some of the questions addressed to me by Mr. Crouch

1. General notion. I see there are strong distortions of my ideas, and
misunderstandings of some rather obvious thoughts. I guess the main reason
is that they were taken separately and so have some kind of uncertainties. I
am afraid that it is not too good practice to start discussion on very short
citations.

2. The question

"Furthermore, Vadim Simonenko of Russia's Federal Nuclear Center at
Snezhinsk (Chelyabinsk- 70) said, " . . technology would be able to cope
with any danger by finding the hazardous object in space and by
adopting measures able to prevent its impact with Earth." However,
since we currently don't know how many asteroids pose a potential threat to
the Earth, and since comets can progressively change their orbits by the
jet action of their warming gas, the mathematics currently available
to determine their orbits is a chaotic estimate at best. Moreover, how
would Vadim Simonenko handle a comet like Shoemaker-Levy 9 if it were on a
collision course with the Earth?"


I was referring to NEO impacts. I am talking about the technology (or it's
better to say: the technologies), which can be used to prevent various types
of impacts. All of them are based on technical background that we have and
are developing now. But I would like to emphasize there isn't any technology
that is ready and could be applied today. Unfortunately, it is a widely held
misconception (in particular, among many scientists, including, highly
respected NEO specialists), that, if we find a real hazardous object, it
would be easy to disperse or deflect it. The mitigation procedures are much
more complicated even in comparison with the most complex technologies of
discovery. Moreover, they need to be different for different objects. And
even dealing with the same type of objects, it will be necessary to account
for the very specific features and properties (orbit, rotation, shape,
internal structure, surface properties, material properties, etc.). To
discuss all these points would take a lot of time and space.

I'll give just several examples but not the complete description of the
peculiarities.

2.1. For small bodies of Tunguska type.

Such objects should be discovered on their terminal way before the impact.
To identify them, it is necessary to have at least three-component system of
observations with a set of several ground-based telescopes (for preliminary
scanning of the sky), 2-3 or more space-based telescopes (for reliable
identification of the object on the collision-way), and radiotelescope (for
precise measurement of the orbit to target the interceptor). It is necessary
to have a rather complex system of ground- and maybe partly space-based
rockets and space-crafts to intercept the object reliably (so, with some
redundancy) on the distance of about one million kilometers from the Earth.
It is necessary to use, in this case, some kind of nuclear explosive devices
(NED). The object should be dispersed by the explosion so that the main part
of the matter should be thrown far beyond the Earth size during the time of
approach to the planet. However, it is a widely held mistake to think that
one could simply use existing nuclear weapons. Even if it is the same
physical package, the device would have to be altered significantly. But and
efficient NED would differ from existing NW in physical package as well.

This technology can be applied for the objects of regional-scale impactors
(less than 1 km). In some sense, it will be even easier to find them. Some
of them can be found by Spacewatch, Spaceguard or similar search telescopes.
The more complicated ones should be the technology of dispersion. It may be
necessary to use simultaneous multiple explosions.

The kinetic-projectile option can not be applied. It needs to have big mass
to deliver precisely with possible corrections on trajectory to the target.
And even it can be performed, the pulse will be rather small to scatter the
debris on sufficiently large distance.

It is obvious that such a system is much more sophisticated than the planned
US Missile Defense System (MDS). However, it would cost less and give more.
It will be really used at least for direct experiments (without NED but with
exploratory packages) for NEO study, and it is very possible that it will be
used for planetary defense a few times per century. In contrast, I note that
the Anti-Ballistic Missile systems, both in the US and SU, have never been
used. I guess, the same fate will be for MDS. I believe that (treated
seriously), it can play the same role for the US as SDI for the SU about
twenty years ago.

2.2. For the global-scale impactor (1-2 km and more).

There is the hope that the main numbers of them will be discovered before
one of them can terminate human existence. In this case, there will time to
study the specific NEO properties in detail and to adjust the technology of
protection. However, the concept of the technology and technical cases
should be ready in any case. I still believe that, at least for the next
decades, it should be based on nuclear explosions, though it is not the best
technology for slight correction of orbits. The reason is that there is
currently no industrial technology to transfer such a big momentum, which is
necessary for the corrections. We see for the Eros data that for some
objects there is a porosity of about 10-20%. Yes, it's not too good for
momentum transfer, but the transfer still works. In this case, it is
necessary to use more sophisticated devices and schemes for explosions
application. We mentioned such rather developed schemes in our presentation
at Hazard Workshop in Tucson even in January 1993. The simple schemes to use
just one explosion not only looks as primitive now, but they actually do not
work for the objects like Eros. Enormous information has been collected
since that time, and I am happy to realize that each time when Nature is
challenging us with a complicated problem, it also provides us with ways to
solve it.

Several notions.

In the case of Eros, we have a rather large object. So, it is possible that
there are internal fractures, which were not opened due to gravitation or
boundaries interaction. It is possible that for the less-size and more
probable rocky global impactors of 1-2 km, there will be a lower level of
porosity. However, regolith on the surface being porous can play a good role
to provide better momentum transfer to internal rocky matter of the object.
So, it is just initial information about the real properties and we should
work with it. I guess some people are in a hurry with hasty conclusions and
recommendations.

It is highly important to study properties of different types of  asteroids
in direct missions.

Some of the asteroids are extinct comets. It is very important to know their
properties because they could need special technology for mitigation. It is
probable that their matter has a low density, high porosity, and low level
of strength. However, even for such objects it is possible to develop a
scheme of explosive momentum transfer which will work like a broom.

2.3. As for comets... 

It is the most complicated problem in all respects: for discovery, forecast,
and orbit correction. There are no dangerous comets we known of today.
However, the threat can arise from newly discovered ones. So, it is highly
important to develop systematic wide-angle observations for newcomers. The
most difficult issue is the accurate forecast of their orbits, especially
for those which can be in a dangerous vicinity of the Earth. It is necessary
to have some prepared beforehand exploratory missions to study such comets.
They will be especially useful to develop the technological operations for
delivery, approach, distant exploration, and final targeting. As for actions
to correct the comet orbit, there are some additional very useful options
due to their specific properties, in particular, deep penetration and
internal distribution of the NED's if such technology is chosen. It's very
possible that properties which look disadvantageous on first sight may
provide us with strong advantages to dealing with such objects.

3. The question

"Finally, Vadim Simonenko expresses his belief by saying, "But
global catastrophes occurred only once every 100,000 to one million
years, with consequences ranging from degradation of the human  race to
its total elimination, . . ." However, the scientific community only
recently deduced that the 1908 Tunguska explosion resulted from as asteroid
impact and scientists were on that sight almost immediately.
Furthermore, only in that last 30 years has the credibility of
global catastrophes such as asteroid/comet impacts and massive volcanic
eruptions been accepted in the scientific community as worthwhile theories
for ecosystem changes. Therefore, I find it rather presumptuous to
assign credibility to prehistoric data that at best only approximated
fractionally what may have actually occurred. Furthermore, when was the
Earth's last great asteroid collision? I don't think Vadim Simonenko or
anyone has the data to enable them to forecast an asteroid or comet
Earth collision with any certainty. In fact because of the mathematical
concept of chaos, even rainy weather forecasting is imperfect. All
that is certain is that it will happen."


This question is more philosophical than technical. Human history always
consists of new events, developments, etc. Even if there are some historical
analogies, it is impossible to enter in the stream of history. For example,
there were no nuclear weapons before the Second World War, there also wasn't
the danger of self-elimination of civilization as it happened during the
Cold War, but we seem to have found a way to solve this problem (at least
for near future, and I hope forever).

Yes, the cosmic impact danger has been accepted gradually by the wider
scientific community during the last 30 years. But the roots of the idea go
much further back in our culture, even much earlier than it was
scientifically mentioned by Edmond Halley three hundred years ago. It is a
privilege of our time that we now have a quantitative approach to this
problem, partly based on the scientific resesarch of Sir Halley and many
others.

And there is another very valuable property of our civilization. When the
problem becomes realized scientifically (or quantitatively), the community
will try to find technological ways to solve it, sometimes even for problems
that lack any obvious practical feedback (like high energy physics problems
these days, or astrophysics). It looks even more correct when we are facing
practically important problems, like nuclear weapon technology development
(first of all, Manhattan Project), information technology (computers,
communication, etc.). In other words, the point is not so much "how long"
but mainly "how deep" the problem concerns the people and our civilization.
I guess there are even more powerful forces which push society to the
solution of viable (like civilization survival) problems as we can imagine
usually. E.g., (1) World War II collaboration of two societies with opposite
social systems to withstand the Nazis; (2) merely self-elimination of the
Soviet Union to resolve the Cold War crisis. At least for the second case,
nobody could predict similar developments.

So, my deep impression with regard to the impact hazard is that if people
have a potential to defend their future existence this potential should
work.

As for randomness in space, it is a deficiency of our knowledge. For the
case as Tunguska, I have shown already how better knowledge can provide
sufficient warning. And I underline once more that the cost of the whole NEO
warning and protection system is less than the average price of loss caused
by small- and medium-scale impacts.

As for so terrible case of the SL-9 impact on Jupiter...

It was a Jupiter family comet, it was disrupted by Jupiter, and prepared by
this planet to the collision. Yes, it is possible that such a large-scale
event can also happen to our planet. But having even the unexperienced
technology which exists now, the danger will essentially be discovered
earlier. The fracturing of the comet by the Earth will not be so plentiful,
the orbit evolution will not be so intensive, etc. And there will be the
chance for people to find the solution instead of unlimited discussions "to
do or not to do" as we have now.

The cosmic events we are discussing are occasional and are due to our
deficiency of knowledge and information. So, the primary task both for
asteroids and comets is to provide reliable technologies for new objects
discovery, follow-up observations, objects properties studies. Even when we
have occasional arrival for parabolic or long-period comets, the essence is
that we have no complete information on solar subsystems properties and
their interaction the Galaxy environment. The experience that we have now
shows be found in future as we have for asteroids, Kuiper objects. But now
we should account this semi-occasional nature for this part of space hazard
problems.

However, even for the most difficult cases such as the large-scale impacts
like the K/T or Permian/Triassic ones, there are, in principle, realistic
opportunities to prevent the impacts if they are of cometary nature. After
all, we are currently creating and developing the scientific and
technological basis for future generations. Their opportunities will be much
better, based on the results we can provide them and on all the new
discoveries they'll have fortune to open. But facing the problem of
civilization survival, each generation should approach it as their own
responsibility, because the next impact might be the final event not only
for this generation but for the civilization at whole. It is also our
obligation for past, present and future generations.

I apologise for the rather long answers, but the topic is much wider than
the opportunity to discuss it in such a limited letter.

       Vadim

=============
(4) AN IMPROVED ENGLISH TRANSLATION OF A RUSSIAN VIEW ON THE IMPACT HAZARD &
PLANETARY DEFENSE

By Anatoly V. Zaitsev <zav@berc.rssi.ru>

E.P. Grondine <epgrondine@hotmail.com>
Note - In a previous life I specialized in reporting on the Soviet Union's
space program, and then on the space programs of that union's successor
states. Most of the scientists in these countries have had several years of
English, and while their English is far better than my own Russian,
sometimes their translation attempts result in what I call "Ruslish". In as
much as A.V. Zaitsev's reports on the SPE Conference's conclusions are
fairly important, I thought that it might perhaps be of benefit to Cambridge
Conference participants to have an easier to read English translation of
them.

While the folowing is solely a re-working of the Zaitsev's translations,
with no reference to the original documents in Russian, it has been checked
by Dr. Zaitsev himself for errors, and those corrections have been made.
Perhaps our fellow Confernce participant, Jim Oberg, who has excellent
Russian, may wish to further clarify or correct it; the corrections of the
spellings of English words with "z"'s, "s"'s, and "c"'s, as well as those
with "-or"'s and "-our"'s, I leave to Benny. - EP

---------------------------------------------------------

I.  SOME OF THE PROBLEMS AND SEQUENCES OF DEVELOPMENT OF THE PLANETARY
DEFENSE SYSTEM
II. POSSIBLE ARRANGEMENT AND PHASES OF DEVELOPMENT OF THE PLANETARY DEFENSE
SYSTEM

By Anatoly V. Zaitsev <zav@berc.rssi.ru>

Report of International Conference
"SPACE PROTECTION OF THE EARTH - 96" ("SPE-96")
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
E-mail: zav@berc.rssi.ru

SOME OF THE PROBLEMS AND SEQUENCES OF DEVELOPMENT
OF THE PLANETARY DEFENSE SYSTEM

ANATOLY V. ZAITSEV
E-mail: zav@berc.rssi.ru
Lavochkin Association, Khimki, Moscow Region, Russia

INTRODUCTION

Among the diversity of dangers which menace the existence of a mankind, the
possible consequences of the impacts of asteroids and comets with the Earth
have only recently been considered in a sufficiently serious manner. It has
become evident that in fact a collision with an object a few kilometres in
size could result in the destruction of all lives on our planet [1¸3].

However, the threat comes not only from large-scale objects, the probability
of collision with which is sufficiently low, but also from relatively small
objects of the Tunguska-meteorite type. This is due to the current abundance
on the Earth of potentially dangerous technogenous objects. (This refers to
nuclear objects, chemical plants, toxic wastes storehouses, etc.-a.v.z.) 
The destruction of any of them in the case of an asteroid impact may result
not only in human victims and hardware damages, but also may become a
specific "trigger" for the development of an ecological crisis or a nuclear
conflict.

Increased understanding of the degree of the danger of such developments and
their effect on the stable development of mankind makes it necessary to take
measures in order to avoid such catastrophes, and/or to decrease the damages
resulting from them. This necessity is confirmed by recently conducted
studies and analyses which have shown that the contemporary level of
technological development of the world's leading countries allows us to
proceed with the creation of a Planetary Defense System (PDS) aimed against
the danger from comets and asteroids [4¸9].

Meanwhile, there are quite, and it is necessary to recognise, well-proven
concerns that a PDS could be used not only for the rescue of mankind, but
also as a means for the destruction of entire countries and regions [10].
Our whole historical experience argues that this is quite possible - perhaps
it is impossible to find a technology which in the hands of the human
creature he has not used in ways harmful for him.  Moreover, the scale of
the disaster possible in the case of the use of a PDS for military purposes
can not be compared with those we have had in the past.

Taking into account the particulars of the anxieties mentioned above, this
paper contains attempts to reveal some of the potentially hazardous problems
and consequences of PDS development. Moreover, a principle goal, according
to which a main emphasis here has been laid directly on the analysis of
negative occurrences, is the necessity of developing measures with the goal
of the non-admission of these problems.

A number of possible scenarios were developed with this goal in mind. Some
of them could be seen as unreal or even absurd, referring to fields which
may be touched on only by fantasists. Nevertheless, such an approach allowed
us to more clearly reveal the node problems of PDS development, formulate
its maximum rigorous requirements, and develop measures for their execution.

At the least it allows us to provide for a maximum reliability and
efficiency of the PDS, so as to remove, or to reduce as much as possible,
the possibility of negative consequences arising from its development and
use.

ANALYSIS OF CERTAIN PROBLEMS OF PDS DEVELOPMENT

At present a permanently operating service for the observation and tracking
of small celestial bodies does not exist.  Nevertheless, many of the
observatories in the world perform such observations, and so, thanks to the
progress reached in the fields of observational instruments and the
development of data recording and processing, we can expect in the immediate
future a sharp increase in the number of asteroids and comets discovered approaching
to the orbit of the Earth and intersecting it.

At that point, an object moving to the Earth along an impact trajectory may
be detected at any time.  The sizes of these objects can be from tens or
hundreds meters to a few kilometres. In the first case a catastrophe of
regional scale can threaten us; in the second one, a global catastrophe can
happen on the Earth.

It is obvious that in the case of a timely warning of the danger, the world
community will take all possible measures in order to prevent the
catastrophe, or to reduce the damages possible from it.  However, the
probability of a favourable outcome of events for us will depend on the
combination of many factors, such as, for instance, the trajectory
parameters and other characteristics of the threatening object, which
provide us with the time margin necessary for the organisation of
counter-measures; the availability of a sufficient number of
corresponding technical means, including means of observation (both optical
and radar based), interception (both launchers and trans-orbital delivery
stages), control, and nuclear and non-nuclear means for affecting an
asteroid or comet; etc.

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

In order to meet this requirement, it is necessary to provide not only for
immediate data delivery, but also to exclude any, even the smallest possible
reasons, which can result in a delay of that data, and even more so, its
loss or deliberate concealment.

All of the possible reasons for such a delay can be conditionally divided
into the following two categories: technical ones and non-technical ones. 
The technical reasons consist of different malfunctions and failures in
communication systems due to both internal errors and external factors. They
combine the consequenses of disaster, along with other natural phenomena,
such as for instance powerful solar flares, which result in malfunctions of
communication systems and computer networks.

The non-technical reasons are due in a considerable degree to the so-called
"human factor". Only a man can intentionally or unintentionally delay or
even hide the information. It can be due to negligence or, on the contrary,
due to an excessive sense of responsibility. For example, a wish can arise
to re-verify acquired data.  With that the possibility can't be excluded of
the loss of valuable time which could be spent taking the specific necessary
counter measures.  We can't exclude numerous other cases, for instance an
intentional hiding of data due to psychological or other illness, or due to
religious or some other motifs.

The simultaneous coincidence of many unfavourable circumstances is possible
as well.

Such an assumption may seem unreal or absurd. But we know of a great number
of examples, where due to different fortuities, including those arising
through human error, great tragedies and catastrophes took place. And so in
situations where the destiny of mankind or some part of it is to be decided,
such fortuities must be excluded or minimized.

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

Based on the above considerations, the first of the most important
requirements of a future PDS is that along with reliable detection of the
dangerous objects by the Ground/Space-Based Observation Service (GSBOS) of
the PDS, it must provide a guarantee of the timely delivery of the acquired
data to the concerned persons and agencies.

Evidently, in order to meet this requirement, it will be reasonable to use
the experience gained by a number of means of military origin: services for
the control of open space, those which warn of the rocket attack, etc. For
instance, the data acquired by the observational means could be delivered to
the centres of control of open space (CCOS's) of several countries, and then
directly delivered to the authorities of these and other countries. For this
purpose, at the initial phase of the Ground/Space-Based Observation Service
(GSBOS) of the PDS deployment, the Centre of Control of Open Space (CCOS) of
the Russian Ministry of Defense and the United States' Department of
Defense's NORAD Centre could be used.

It is obvious, that in parallel to or after the delivery to the centres of
control of open space (CCOS's), the data on detected celestial bodies must
be delivered to astronomical and other scientific organizations. Moreover,
it is important to provide guaranteed delivery of data to the authorities of
those states on whose territory, as per forecast, a relatively small
asteroid will fall. This is necessary in order to exclude the temptation to
damage or even destroy these countries by not announcing a danger.

In fact, it is necessary to note that accurate prediction of impact point is
hard to provide due to its great spread, resulting from poor knowledge of
any falling object's parameters, particularly aerodynamic ones [11]. 
However, at some point the development of observational means will
contribute to [making possible] the execution of such a prediction; so it is
necessary to take all measures to exclude the possibility of the concealment
of data on dangerous asteroids for any reasons.

Preliminary studies show that this requirement may be fulfilled most simply
and reliably with the development of the space segment of the
Ground/Space-Based Observation Service (GSBSO). In this case it will be
relatively easy to provide for the 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 means of observation.

Besides those mentioned above, there are also a number of other reasons to
hide data on asteroids, including for instance for their utilisation in the
future for a military purpose, or as a source of raw material resources.
During the process of the observation of celestial objects, such relatively
small objects can be detected that with a corresponding correction of their
orbits they could be used to strike the territories of different countries.

As was discussed above, in the nearest future such an operation could be
fulfilled.

And it is not obligatory to use the capabilities of the PDS for this
purpose. It would be sufficient to study well the characteristics of a
celestial body during the execution of usual space missions, and then to
push it, using any known method, to an Earth impact trajectory.  For this
aim, in some favourable cases it may happen that it is sufficient to use
even the spacecraft's own propulsion system, or the impulse of the
spacecraft's collision with the asteroid. From this perspective the "Space
Billiards" method [12] could be used, which allows  change of the trajectory
of a sufficiently great body through the process of consecutive collisions
with smaller objects.

So the possibility can not be excluded of the use of spacecraft, including
those of a scientific designation, as a means for the deflection of
asteroids in order to destroy targets on the Earth. Apparently, in order to
exclude such actions it will be necessary to accept certain restrictions on
some active operations in the missions of interplanetary spacecraft to small
celestial bodies. Correspondingly, similar restrictions must be imposed on
the rocket/space capabilities of the PDS, which will allow it to fulfil the
requirement of the impossibility of its military use.  In order to meet this
constraint, the available great experience in the international control of
arms could be used, which provides some confidence in the possibility of
finding a solution to this problem.

It is necessary also to take into account the fact that at present asteroids
are studied for  their quality as sources of the raw materials for our
future generations. Thus the temptation could appear to hide data on
asteroids potentially suitable for this purpose, in order, for example, to
monopolize the property rights of these resources. To avoid such a
situation, it is necessary to establish procedures regulating the problems
of the investigation and utilization of these bodies' resources.

The problems discussed above on data provision have one important aspect.
That question is,  after the reception of data on a potential danger,
together with the 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's population about this fact or not?

This problem is represented as more complicated than that of the operational
warning of competent persons and agencies, which has in higher degree an
organisational/technical character.  But the "announcement dilemma" touches
upon an enormous complex of moral, ethical, religious, and other problems,
discussion of which is far outside of the framework of this paper and the
author's competence.  Maybe it would be more reasonable, after the
corresponding study of this problem by experts and its wide public
discussion, to accept an international law or code of regulations for these
critical situations, if, certainly, these documents have not already been
developed yet. These will have to regulate the behaviour of all persons
touching upon this problem - from the first discoverer, to the state
authorities [responsible for] coming to a decision on a danger, population
warning, and evacuation.

Certainly, at the time of PDS development it will be necessary to solve a
variety of problems more individual, but not less important, than those
discussed above. In particular it will require an increase in the number of
allowable azimuths of launch for the launch vehicles used for the launching
of the means of interception of dangerous celestial bodies; provision for
the  safety of launch and the use of the nuclear means of destruction; the
removal of or minimization of the possibility of damage by fragments of the
destroyed object; etc.  However the restricted limits of this paper do not
allow us to carry out even simplified analysis of these problems.

POSSIBLE CONSEQUENCES OF PDS DEVELOPMENT

In the case of the acceptance of effective measures, one can hope that the
problems of guaranteed provision of data and no use of the PDS for military
purposes can be solved.

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

Such a refusal could be expressed in either an evident and implicit form. In
the first case it could be motivated, for instance, by a danger that the
fragments of the destroyed celestial body could reach the territories of
states which would not suffer if the PDS was not under use. In the second
case, for instance, a feign of malfunction of the intercepting devices, miss
at interception, etc. could be used.  The hiding of data is also possible,
which was discussed above. Hence, one more requirement of the PDS is as
follows: guaranteed defense of any country.

It becomes clear from the examples above that non-use of a PDS in a critical
situation could  provide a threat not lower than its direct use for military
purpose. Thus excluding the dilemma of whether to use or not to use the PDS
means of defense can appear as one of the most important, and may become the
most complicated problem, associated with protecting the Earth  against the
asteroid danger.  Solution of "the dilemma of the PDS non-use" will require
development of a wide set of measures, and it is possible that the first of
such measures can be the adoption of an international treaty forbidding the
development and monopoly possession of the PDS by any one state, or by a
group of states united in single military/political block, or in one
identical to it.

It seems that one of the most acceptable options for the solution of this
dilemma could be the development of the PDS simultaneously in Russia and the
US, which have, in fact, all the necessary basic means, or their prototypes,
for the development of such a system. In this case the combined
Ground/Space-Based Observation Service (GSBSO) and autonomous interception
services could be created.

Development of a combined Ground/Space-Based Observation Service (GSBSO),
which could include the observation facilities of other countries, would
allow [it] to provide for execution of the first requirement: guaranteed
operational delivery of the acquired data to corresponding authorities and
agencies, as well as the exclusion of a possibility of data hiding.

At the same time, creation of autonomous interception services on the basis
of the national rocket/space, nuclear, and other means of Russia and the US
would allow the elimination of, or considerable reduction of, the risk of
PDS "non-use".  Moreover, it would even increase PDS reliability through the
functioning of means based on different principles, and for some other
reasons as well.

It is obvious that a "non-use dilemma" can arise only in the case of
collision with a relatively small asteroid.  In the case of a global
catastrophe, Humanity will combine its efforts for struggle against a common
danger.  However, mankind's capacities for warding off of the threat from
space will never be unlimited.  A situation may arise where we will not be
able to evade from a global catastrophe.

Perhaps in this case the single alternative to general destruction could be
the option of using a lunar base for the saving of a small colony of
terrestrial people. After the decay of the catastrophic events on the Earth,
they could come back and populate the Earth again.  Thus, to the numerous
arguments in favor of the development of space programs, including the
colonization of the Moon, can be added one more - as a margin mankind must
have, a "Noah's Ark-2".

It is necessary to note, that not only the possibility of the perishing of
the whole of mankind, but also any of its parts, compel us to reflect on the
possibility of preserving some minimum of spiritual and material valuables
which would allow the regeneration and restoration of losses from any
possible catastrophes of regional and global scale.  This aim would require
the development and execution of a special program, which could be named
"Phoenix", including a wide range of measures for the fulfilment of such
objective. Apropos of which, maybe some similar things existed in history,
which could explain the extremely high level of development of some ancient
civilizations.

The analyses performed in this work, concerning some negative scenarios of
possible events, have not had for their aim forcing a horror around the
asteroid danger problem, or finding somebody guilty of evil intentions. As
was discussed at the beginning of this paper, it was done with the objective
of formulating better-proven requirements to be imposed on the PDS.
Fulfilment of these requirements will allow us to exclude the possibility of
realisation for all of those negative options of the development of events
considered, and for a far larger number of those not considered, leaving
them for use only as scenarios in science fiction, movies, etc.

CONCLUSIONS

The results of the analysis executed of possible problems and consequences
of PDS development allow us to formulate a number of the most important
general requirements which the PDS must satisfy.

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

It is clear, that during PDS development, deployment, and operation, it will
be necessary also to satisfy 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
concealment of data on both  threatening celestial bodies and those which
show interest as resources of raw materials.

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

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

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

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

Undoubtedly, more detailed study of the problems concerning protection
against the asteroid and cometary danger will result in the revelation of
other more numerous problems of the most varied character. But even from the
list above it becomes clear that the PDS deployment will put before mankind
a number of essentially non-ordinary problems, each of which may be not only
from the point of view of the science/engineering, but also from points of
view of organization, politics, law, morality, ethics, etc.

The possibility of their solution has no doubt. Nevertheless, this will
require the combination  of efforts of a great number of experts in fields
not only of the natural sciences, but also of the human sciences. As a
result, work on PDS development can become a peculiar catalyst of
development for many industries and technologies, as was the development of
such great projects, as for instance that of space; one that will favour not
only the defense of, but also the development and unity of Humanity.

REFERENCES

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,
1992.

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.

================

POSSIBLE ARRANGEMENT AND PHASES OF DEVELOPMENT
OF THE PLANETARY DEFENSE SYSTEM

By A. V. ZAITSEV

Report of the International Conference
"SPACE PROTECTION OF THE EARTH - 96" ("SPE-96")
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
E-mail: zav@berc.rssi.ru
Moscow region, Khimki-2
Leningradskoe shosse., 24


POSSIBLE ARRANGEMENT AND PHASES OF DEVELOPMENT
OF THE PLANETARY DEFENSE SYSTEM

A. V. ZAITSEV
E-mail: zav@berc.rssi.ru
Lavochkin Association, Khimky, Moscow Region

INTRODUCTION

In fact at present there is no doubt about the existence of a real danger
originating from the impacts of asteroids and comets with the Earth, one
which threatens its biosphere, so this circumstance does not require
additional argument here.  Previously conducted studies [1-4] show that the
current levels of the development of technologies allow us to proceed
immediately with the practical realization of measures providing for
protection against this danger.

This work develops and adds some conditions related to the earlier proposed
principles of construction of a 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 the Earth, but also other bodies of the Solar System, in the first
place  the Moon. This will be necessary not only for the protection of lunar
colonies, but also for preventing the consequences of the impacts of great
bodies with the Moon, [consequences] which are probably unfavourable for the
Earth's population. For instance, these effects may include the possibility
of great fragments falling onto the Earth, the pollution of near-terrestrial
space, or a change in the Moon's orbit.

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

1. SOME OF THE MOST IMPORTANT PDS REQUIREMENTS

As was shown in earlier works, in order to effectively protect the Earth,
and in the 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 obvious that the PDS must provide protection both from those celestial
bodies which will be detected several days before their collision with the
Earth, and from the those whose impact  can be predicted many years in
advance. Therefore the PDS must have at least two ranges of  target
detection and interception: an operational one and a stand-off one [3,5-7].

But taking into account the rarity of impacts with the Earth of even
relatively small asteroids (about once per century), it appears unreasonable
to develop all PDS means and maintain them in a state of 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 an approach to PDS configuration wherein most of its
components are based on facilities of "double" utilization and they are
combined with components of systems and facilities for another use.  This
would allow the maintainance of some of the PDS elements in an operational
mode, which conditionally could be called a "virtual" one. This implies that

a number of PDS components will not be included in its composition. However,

in case of the critical situation, they must be promptly developed or
evolved from other systems or services for fulfillment of PDS tasks.

Of course, once in the "virtual" mode, the System will not be able to
fulfill its functions completely. Therefore, Ground/Space-Based Service of
Observation (GSBSO) facilities permanently in action must be created, which
would provide for the constant monitoring of deep space; and the necessary
minimum of means providing for operational counter-measures against the
danger must be deployed as well.  At the same time, stand-off interception
could be quite well kept in a mode close to the "virtual" one. So therefore,
it is clear that the use of the "virtualization" principle will allow us to
decrease considerably the expenses and delays of PDS deployment.

Many other constraints must be taken into account at 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
impact of a small celestial body;
· provision of the guaranteed use of PDS means for the protection of
any country's territory against a falling celestial body.

In order to fulfill the first requirement, a combined international
Ground/Space-Based Service of Observation (GSBSO) could be developed, which
would exclude the possibility of losses, delays, or concealments of data on
celestial bodies, including those threatening to the Earth,  those
representing an interest to somebody from the point of view of their future
utilization  with the aim of the Earth bombardment by asteroids, or those
asteroids which may be utilized as sources of the raw materials. The most
simple and reliable method for the satisfaction of this  requirement could
be the provision for the simultaneous and independent reception of data from
the space segment of the observation service, arranged at different points
of the globe.

In order to satisfy the second requirement, it is necessary to create
several autonomous Ground/Space-Based Service of Interception (GSBSI)
segments on the basis of the missile/space, nuclear, and other facilities of
Russia, the US, and possibly of some other states (Europe, China, India, and
Japan - zav), who possess identical means. This would allow the exclusion of
potential cases of PDS non-use for the defense of any state for political,
technological, or some other reasons. Surely, the feasibility of these and
other requirements represents a sufficiently complicated problem.
Nevertheless, the experience of development of the complex rocket/space,
combat, and other systems provides confidence in the possibility of their
fulfillment.

Let us consider the possible configurations of the PDS architecture.

2. GROUND/SPACE-BASED SERVICE OF OBSERVATION  (GSBSO)

The necessity of the reliable detection of the dangerous celestial bodies
implies for the  Ground/Space-Based Service of Observation (GSBSO), and
particularly for its Space Observational Segment(SOS), a great number of
complicated requirements for its permanent monitoring of deep space: the
value of its range of 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 the principle
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 background on the necessity of the development of a
Space Observational Segment (SOS) and possible configurations for its
construction.

Below we will discuss one of the possible options for the construction of an
operational Space Observational Segment (SOS) designed in the first place
for the detection of small celestial bodies in the nearest proximity to the
Earth. (at distances up to few tens of millions of kilometers - avz).

Analyses of the family of possible trajectories of asteroids moving along
Earth impact orbits were carried out to determine the areas to be tracked by
Space Observational Segment (SOS) facilities.  For 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., respectively.  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 those trajectories are
shown which lay in the ecliptic plane. The picture will be practically
identical for inclined trajectories. Two closed curves show regions whose
limits correspond to an Earth approach time 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. those with orbits
having eccentricities close to 1. The approach times of asteroids with low
eccentricities from these frontiers will be considerably greater.
In order to provide for the tracking of these regions, it is considered
reasonable to put spacecraft equipped with telescopes into orbits coinciding
with the Earth's orbit, but with some lag or advance relative to the Earth.
With that, during the observations of celestial bodies it is possible to
provide sufficiently acceptable phase angles, and what is very important,
that the checked areas 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. [In this case the telescope looks back at the
Earth, with the Earth is in the center of this angle at 30o. - epg] Thus,
the checked area of celestial sphere will be decreased nearly by an order in
comparison with observations [made] from the Earth, for which it is
necessary to keep under control [observation-epg] the whole celestial
sphere. In addition, the proposed option for spacecraft location provides
conditions good enough for observing asteroids approaching the Earth from
Sun-side - it is impossible to observe such asteroids from the Earth at all.

Analyses conducted [10] show that by using already existing optic/electronic
observational facilities, scanning of the area under consideration is
possible within an interval of several hours, which is quite sufficient for
operational warning of a danger. Only a few spacecraft need to 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 for the observation of the monitored
area under different aspect angles.

Development of the proposed option is possible beginning as early as the
immediate future by observing from the Earth those regions located in its
orbit along the path of its motion at the distance of 10-20 million
kilometers. In this case all the necessary initial data for the [Space
Observational Segment (SOS)] spacecraft and its telescope will be acquired,
and statistical data on asteroids intersecting the Earth orbit will be
updated.  The proposed method can be used in order to provide global,
widespread ground-based observations of the region of space lying along
Earth's orbit.

If one confines oneself to the observation angles relative to the Sun
greater than ±45o, in this case it will be possible to observe from the
Earth the toreidal region along its orbit with a cross-section of a few
millions of kilometers and a length of about 500 million kilometers, i.e. on
half of the Earth's orbit. In this case distant regions of small angular
sizes can be observed with the majority of the greatest astronomic
instruments, such as the BTA (Zelenchuk), the Palomar Telescope, etc., and
even by the Hubble Space Telescope. It will be possible to observe the
nearer regions using smaller telescopes, but with larger fields of view.

The realization of such an international program, which conditionally can be
named as "TORE", would allow a considerable increase in the efficiency of
detection of asteroids intersecting the Earth's orbit, [better] specify the
degree of the asteroid danger, and better reasonably formulate Space
Observational Segment (SOS) requirements.

Afterwards, spacecraft with telescopes could be injected into the regions of
the Earth's orbit at angles of about ± 90o relatively to the Sun-Earth
direction, which will provide an observation on the Earth of portions of its
orbit invisible from the Earth. Thus, the whole space region along Earth's
orbit will be monitored, which will allow us to provide early warning of the
overwhelming majority of the bodies intersecting the Earth's orbit.

In this case it will be possible to combine the problem of detection of
asteroids intersecting  Earth's orbit with observations of the side of the
Sun invisible from the Earth, which  represents an essential interest for
the forecasting of solar activity.  Such a combination of objectives would
be reasonable, for instance, in the framework of the GEKATA, SPINS, etc.
projects [11,12].  Realization of the "TORE" program must be considered as
the first step in the development of the Ground/Space-Based Service of
Observation (GSBSO).

Then, as the technical facilities are upgraded, it will be necessary to
provide for global monitoring of the whole celestial sphere in order to
exclude the possibility of an unexpected appearance of a hazardous celestial
body with a great orbital period, or, for example, in the case of a possible
change of trajectories of celestial bodies which did not early threaten to
the Earth. These would be due to the gravitational perturbations at the
planet's fly-by or as a result of collision with other small celestial
bodies.  [This would also seem to include long period comets. - epg]

3. GROUND/SPACE-BASED SERVICE OF INTERCEPTION  (GSBSI)

Depending on the above-mentioned principles of PDS construction, the
Ground/Space-Based Service of Interception (GSBSI) will be based on
rocket/space facilities: launch vehicles, spacecraft, ground-based
infrastructure (space launch sites, communication, guidance and control
facilities, etc.). For many reasons for the time being it is unreasonable to
place in space facilities destined for the provision of counter-measures
against the asteroid danger [3,7].

Among all the variety of currently available launch vehicles, the
requirements for little [minimum]  delay in the preparation for launch,
payload mass, etc., are mostly satisfied by the launch vehicles "Conversion"
(constructed on the basis of SS-18 ICBMs - avz) ["converted" from missiles
freed from military use through the START treaties - epg], Zenith, and
Proton.  The Zenith Launch Vehicle especially can be marked out, which for
sufficiently large injected payload capability (12 tons in parking
orbit-avz) has unique performance related to the immediacy of launch. After
its erection onto the launch table, it can be prepared for launch in 1.5
hours, and the next launch from the same table can be executed in 5 hours
[13]. No other launch facility/rocket in the world has such a capability.
Such performance makes this launch vehicle irreplaceable for the service of
effective interception.

The [Our] rocket/space industry has also a number of flight-proven
spacecraft and advanced projects which could serve as the basis for the
development of a Reconnaissance-Spacecraft and an Interceptor-Spacecraft.
These types of spacecraft could be derived from spacecraft developed by the
Lavochkin Association, such as the Mars-96 (Phobos) series, the SKIPPER
space-bus, the Orbital Module for the Mars-2001 mission, etc.

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

Let us consider an option for effective intercept, a conception based upon
the approaches stated in this and proceeding works [6,7]. Let us take one of
the most critical conditions as an initial precondition, where the
time-period from the moment of asteroid detection up to
its impact with the Earth does not exceed 3 days [72 hours-epg]. 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.

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

·  T = 0. Asteroid detection.
             Warning.
             Beginning of preparation of the rocket/space facilities for the launch.  

Involvement of additional observation facilities.
             Updating of the asteroid parameters.
             Making a decision on spacecraft launch.
·  T » 12 hours. First intercept-spacecraft launch.
·  T » 18 hours. First reconnaissance-spacecraftlaunch.
·  T » 24 hours. Second (reserve) reconnaissance-spacecraft launch.
·  T » 48 hours. Second (reserve) intercept-spacecraft launch.

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

The first Intercept-Spacecraft is launched with the aim of encountering the
asteroid at a maximum distance from the Earth. The
Reconnaissance-Spacecraft, due to their smaller mass, will be accelerated to
a considerably greater velocity than the Intercept-Spacecraft, and by
outstripping the first Intercept-Spacecraft, will be the first ones which
meet the asteroid.

On the basis of the data acquired from these Reconaissance-Spacecraft, the
Space Flight Control Center (SFCC) generates a model of this body which is
utilized for the preparation of all of the necessary data which is
transmitted to the on-board computers of the Intercept-Spacecraft. All of
these operations last about 8 hours (from the time of the
Reconnaisance-Spacecraft's rendevous with the asteroid - zav), and then the
first Intercept-Spacecraft performs its maneuver of approaching to the
asteroid.  At their meeting the nuclear warhead is exploded and the asteroid
is destroyed or deflected from its Earth impact trajectory.

Some time prior to the collision, two small Observational-Spacecraft must be
separated from the Intercept-Spacecraft with the task of observing the
results of the executed operation from  safe distances. In the case of miss
or the necessity of additional effect upon the asteroid, the second
Intercept-Spacecraft will be used.

By using the Zenit launch vehicle for launch of the Intercept-Spacecraft
along the energetically optimum trajectory, the mass of the warhead to be
delivered to the asteroid can reach 1500 kg. The power of such warheads is
at least 1.5 Megatons [14], which will allow the destruction of an asteroid
about 100 meters in diameter [15].

An identical sequence of events can be used for execution of the operations
of the long-range Ground/Space-Based Service of Interception (GSBSI).  In
this case the Proton launcher would   provide the launches.  It is necessary
to note that for interception at distant frontiers outside of Mars's orbit
and inside of Venus's orbit, as well as for interceptions far from the
ecliptic plane, it will be necessary to use spacecraft equipped with solar
or nuclear electrical/rocket propulsion subsystems.

Of course, this picture is fairly schematic. Its realization requires
solving a number of problems. However these 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 the "SPACE PATROL" Project [17,18], during the investigation of
asteroids flying near the Earth.

Besides the usage of national rocket/space facilities, in the framework of
the international "SYNTHESIS" Project it appears reasonable to develop
versatile reconnaissance and intercept spacecraft on the basis of the best
world space technologies, taking into account the possibility of their
launches by different launchers, provision of communication with them, their
guidance control, etc. Their development could be done in the framework of
international space missions, for example missions to the small bodies of
the Solar System. Provision of a small reserve of such spacecraft will allow
the use of them, for instance, for urgent missions to suddenly appearing
objects of the type of comets Hale-Bopp, Hyakutake, etc.. [long period
comets - epg]

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

CONCLUSIONS

Presented here was a brief exposition of the approaches to the Planetary
Defense System architecture, one not pretending to a completeness of
envelopment of the whole of issues of the problem, but one nevertheless
showing the reality of PDS development on the basis of the up-to-date
technologies.

Based on the necessity of meeting a number of the most important PDS
requirements, it is necessary to accept that the PDS must include a joint
international Ground/Space-Based Service of Observation (GSBSO), whose
primary components must be represented by spacecraft equipped with the
telescopes and injected into orbits coinciding with the Earth's orbit, at
distances of 10-20 million kilometers from it, as well as several autonomous
Ground/Space-Based Service of Interception (GSBSI) segments set up on the
basis of the national rocket/space, nuclear etc. means of Russia, the US,
and perhaps of some other countries [Europe, China, India, and Japan - zav].

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 of these projects can be executed in the framework
of the realization of the national and international programs for the
exploration of outer space, i.e. they will became the key components of
these programs. So that, at 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 their assistance and advice in writing this paper.

REFERENCES

1. 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, 1986. -17 pp.,

2. 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.

3. 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.

4. 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.

5. Kovtunenko V. M., Bojor J. A., Zaitsev A. V., Kotin V. A., Maglinov I.D.,

Tchesnokov A. G. - Analysis of Some Problems in Building the System for
Detection of Hazardous Space Objects and Its Design Parameters// Report of
International Conference "SPE-94", Snezhinsk, Sept. 26-30, 1994.

6. Kovtunenko V. M., Alyabiev S. P., A. V. Zaitsev, Kotin V. A., Feshin I.V.

- Analysis of Some Problems in Building the System for Interception of
Hazardous Space Objects and Its Design Parameters// Report of International
Conference "SPE-94", Snezhinsk, Sept. 26-30, 1994.

7. Kovtunenko V. M., Zaitsev A. V. etc. - Principles of construction of the
System of prevention of the Earth collision with asteroids and comets//
Lavochkin Association, Babakin SRC. 1995. -69 pp.

8. Zaitsev A. - Some of Problems and Sequences of Development of the
Planetary Defense System// Report of International Conference "SPE-96",
Snezhinsk, Sept. 23-27, 1996.

9. Kovtunenko V. M., Rogovsky G. N., Sukhanov K. G., Tchesnokov A. G.,
Papkov O. V., Bojor J. A., Zaitsev A. V., Kotin V. A., Maglinov I. D.,
Feshin I. V. - Opportunities of Creation of the Earth Protection System From

Asteroids and Comets on the Basis of Modern Technologies// Report on
International Conference "Asteroid Hazard-95", May 23-25, 1995,
St.Petersburg.

10. Dobrov A. V., Zaitsev A. V., Maglinov I. D., Sokolova Ju. G., Tchesnokov

A. G., Sveshnikov M. L., Sokolsky A. G. - Possible Approaches to Forming of
Space Observation Service for Asteroids and Comets// Report on International

Conference "Asteroid Hazard-96", July 15-19, 1996, St.Petersburg.

11. Kovtunenko V. M., Tchesnokov A. G., Avdyushin S. I., Malyshev A. B.,
Zaitsev A. V. - Ground/space-Based System for the Global Heliogeophysical
Monitoring// In Optical Monitoring of the Environment: CIS Selected Papers,
Nicolay N. Belov, Edmund I. Akopov, Editors, Proc. SPIE 2107, p.p.16-28
(1993).

12. Pizzo V. J. - The Findings of the SPINS Science Workshop//
SpaceEnvironment Laboratory, Boulder, November, 3-5, 1993

13. Menshikov V. - Baikonur// Aviation and cosmonautics, 1993. N4. p. 8.

14. Sykes Lynn R., Davis Dan M. - About Power of the Soviet Strategic
Weapons// Scientific American, January 1987, Vol. 256, No. 1.

15. Shubin O. N., Nechai V. Z., Nogin V. N., Petrov D. V., Simonenko V. A. -

Nuclear Explosion Near Surface of Asteroids and Comets// Common Description
of the Phenomenon. Report, "Planetary Defence Workshop", Livermore, May
1995.

16. Zaitsev A. V., Mikisha A. M., Smirnov M. A., Sokolsky A. G. -
Possibilities of Informational-Ephemeridical Support of "Space Patrol"
Mission// Report on International Conference "Asteroid Hazard-96", July
15-19, 1996, St.Petersburg.

17. Kovtunenko V. M., Zaitsev A. V. etc. - "Space Patrol" Project//Lavochkin

Association, Babakin SRC. 1995. 8 pp.

18. Kovtunenko V, Rogovsky G., Chesnokov A., Sukhanov K., Papkov O., Bojor
Ju., Zaitsev A., Kotin V., Maglinov I., Feshin I. - Space Patrol Project as
a First Stage of the Earth Asteroid Protection System
Deployment//IAF-95-Q.5.09. 10 pp., ill.

Copyright 2000, Anatoly V. Zaitsev <zav@berc.rssi.ru>

=============
(5) FAO GERMAN/AUSTRIAN CCNet SUBSCRIBERS: METEORITEN-FRUEWARNSYSTEM
   (EARLY WARNING SYSTEM FOR METEORITES)

From Daniel Fischer <dfischer@astro.uni-bonn.de>

Lieber Benny,

gerade erhielt ich (ueber einen Pressemitteilungsdienst) folgende Einladung:

---------------------------------------------------------------------------

Einladung zur Praesentation "Dark Expedition" / Meteoritenfruehwarnsystem
(*Invitation to attend the presentation of "Dark Expedition", an alleged
early warning stystem for "meteorites" (sic), developed by software company
RavenSpace.)

Muenchen (ots) - Am naechsten Donnerstag findet in Muenchen eine
Veranstaltung mit fuehrenden Wissenschaftlern auf dem Gebiet der Astrophysik
und Software statt. Hintergrund dieser Veranstaltung ist die Vorstellung
eines Fruehwarnsystems fuer Meteoriten auf Basis des
neuentwickelten Softwaresystems RavenSpace. Erstmalig wird hierbei
'Kuenstliche Intelligenz' zum Einsatz gebracht, um die bei der
Weltraum-Observation anfallenden, enormen Datenmengen zeitnah
auszuwerten, komplexe Zusammenhdnge zu erkennen und Entscheidungsgrundlagen
fuer notwendige Massnahmen zu liefern.

Aktuellen Bezug erhdlt die Prdsentation durch die folgende, im Januar
erschienene dpa Meldung:

"Cambridge (dpa). In einem Abstand von nur rund 300.000 Kilometern ist Mitte
Januar ein etwa 30 Meter grosser Brocken an der Erde vorbeigerast. Dies
meldete das Minor Planet Center der
Internationalen Astronomischen Union in Cambridge (Massachusetts) am
Mittwochabend."

Hier weitere Details zur Veranstaltung:

   "Dark Expedition"
   am 08. Februar 2001
   um 14:00 - 16:30
   Deutsches Museum / Forum der Technik
   (Museumsinsel 1, Muenchen)

   Die Referenten

   Herr Professor Dr. Jim Heasly, University of Hawaii, Department for
Astrophysics

   Herr Hardy Schloer, CTO RavenPack AG

   Herr Dr. Meier-Fritsch, Compaq Computer GmbH, Germany

werden Ihnen unsere wissenschaftliche Zusammenarbeit auf dem Gebiet der
Astrophysik mit f|hrenden Institutionen in diesem Bereich praesentieren. Das
Software-System RavenSpace wird im Laufe des Jahres 2001 auch zum
kommerziellen Einsatz kommen, um in Unternehmen umfangreiche Datenmengen zu
analysieren, auch dort komplexe Zusammenhdnge zu erkennen und entsprechend
intelligente Entscheidungsgrundlagen bereitzustellen. Die in RavenSpace
integrierte k|nstliche Intelligenz ermvglicht, dass das System selbstdndig
lernt, auch nicht explizit vorprogrammierte Auswertungen und Analysen
vornimmt und Entscheidungen vorbereitet.

Bitte beachten Sie, dass die Prdsentationen teilweise in englischer Sprache
gehalten werden.

Wir freuen uns, Sie am Donnerstag begruessen zu duerfen!

RavenPack AG
Wladimir Brandtner Sales & Marketing
Tal 34
80331 M|nchen
Phone: +49 (0)89-242978-100
Fax: +49 (0)89-242978-110
E-Mail: mail@ravenpack.com
http://www.ravenpack.com

------------------------------------------------------------------------

Dieser Website konnte ich bislang allerdings keine NEA-relevante
Informationen entlocken ...

Gruss, Daniel


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