NEO News (01/03/01) Chapman White Paper

Dear Friends & Students of NEOs:

This edition of NEO News features a new “white paper” on the NEO
impact hazard by Clark Chapman, Dan Durda, and Robert Gold. I have
reproduced here only the Executive Summary, Introduction, and
Recommendations. The full paper, including table and references, is
available on the Web at
(http://www.boulder.swri.edu/clark/neowp.html).

Also included in this message is an announcement of a community forum
this month on the proposed NASA Dawn mission to orbit main-belt
asteroids Ceres and Vesta.

David Morrison

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THE COMET/ASTEROID IMPACT HAZARD: A SYSTEMS APPROACH

Clark R. Chapman and Daniel D. Durda

Office of Space Studies

Southwest Research Institute

Boulder CO 80302

Robert E. Gold

Space Engineering and Technology Branch

Johns Hopkins University Applied Physics Laboratory

Laurel MD 20723

24 February 2001

EXECUTIVE SUMMARY

The threat of impact on Earth of an asteroid or comet,
while of very low probability, has the potential to create public
panic and — should an impact happen — be sufficiently destructive
(perhaps on a global scale) that an integrated approach to the
science, technology, and public policy aspects of the impact hazard
is warranted. This report outlines the breadth of the issues that
need to be addressed, in an integrated way, in order for society to
deal with the impact hazard responsibly. At the present time, the
hazard is often treated — if treated at all — in a haphazard and
unbalanced way.

Most analysis so far has emphasized telescopic searches
for large (>1 km diameter) near-Earth asteroids and space-operations
approaches to deflecting any such body that threatens to impact.
Comparatively little attention has been given to other essential
elements of addressing and mitigating this hazard. For example, no
formal linkages exist between the astronomers who would announce
discovery of a threatening asteroid and the several national
(civilian or military) agencies that might undertake deflection.
Beyond that, comparatively little attention has been devoted to
finding or dealing with other potential impactors, including
asteroids smaller than 1 km or long-period comets. And essentially
no analysis has been done of how to mitigate other repercussions from
predictions of impacts (civil panic), how to plan for other kinds of
mitigation besides deflection (e.g. evacuation of ground zero,
storing up food in the case of a worldwide breakdown of agriculture,
etc.), or how to coordinate responses to impact predictions among
agencies within a single nation or among nations.

We outline the nature of the impact hazard and the
existing ways that a predicted impact would be handled at the present
time. We describe potential solutions to existing gaps in the
required approaches and structures (both technical and governmental)
for dealing with impacts, including the kinds of communications links
that need to be established and responsibilities assigned.

We recommend crafting, adoption, and implementation of
improved procedures for informing the broader society about the
impact hazard, notifying the public and relevant officials/agencies
about an impact prediction, and putting in place (in advance of such
predictions) procedures for coordination among relevant agencies and
countries. We recommend that pro-active steps be taken, perhaps
through a high-visibility international conference and other types of
communication, to educate the broader technical community and public
policy makers about the impact hazard and the special aspects of
mitigating this atypical hazard. For example, the most likely
international disaster that would result from an impact is an
unprecedentedly large tsunami; yet those entities and individuals
responsible for warning, or heeding warnings, about tsunamis are
generally unaware of impact-induced tsunamis. We also recommend that
additional attention be given to certain technical features of the
hazard that have not received priority so far, including the need to
discover and plan mitigation for asteroids smaller than 1 km and for
comets, study of the potential use of space-based technologies for
detection of some kinds of Near-Earth Objects, study of chemical
rockets as an approach to deflection that is intermediate between
bombs and low-thrust propulsion, and further evaluation of the risks
of disruption (rather than intended deflection) of an oncoming object.

Finally, we believe that international human society (and
elements of it, like the U.S. government) needs to make an informed,
formal judgement about the seriousness of the impact hazard and the
degree to which resources should be spent toward taking steps to
address, and plan for mitigation of, potential cosmic impacts. The
existing unbalanced, haphazard responses to the impact hazard
represent an implicit judgement; but that judgement does not
responsibly address the extraordinary and unusual consequences to
nations, or even civilization, that could result from leaving this
hazard unaddressed in such an arbitrary, off-hand way. For example,
we believe it is appropriate, in the United States, that the National
Research Council develop a technical assessment of the impact hazard
that could serve as a basis for developing a broader consensus among
the public, policy officials, and governmental agencies about how to
proceed. The dinosaurs could not evaluate and mitigate the natural
forces that exterminated them, but human beings have the intelligence
to do so.

{This SWRI White Paper is also available at:
www.boulder.swri.edu/clark/neowp.html}

INTRODUCTION

The impact hazard from near-Earth asteroids and comets
has evolved from a science fiction scenario to a serious societal
issue during the past twenty-five years. The scientific community
began to understand the implications for life on Earth of errant
small bodies in the inner solar system in 1980 when Nobel Laureate
Luis Alvarez and his colleagues published an epochal paper in Science
(Alvarez et al. 1980) advocating asteroid impact as the cause of the
great mass extinction 65 million years ago that led to the
proliferation of mammal species. The same year, the NASA Advisory
Council advocated study of a modern-day cosmic threat to
civilization, leading to a formal study (The Spacewatch Workshop,
chaired by Eugene Shoemaker) the following year.

A decade later, these scientific issues first received
significant public consideration when lobbying efforts by the
American Institute of Aeronautics and Astronautics (AIAA) and others
resulted in action by the U.S. House of Representatives, which
directed NASA to study the impact hazard. NASA responded by
organizing an International Conference on Near-Earth Asteroids and
two study workshops, one (chaired by David Morrison) leading to
recommendations (Morrison 1992) for a telescopic “Spaceguard Survey”
of the larger Near Earth Asteroids (NEAs) and the second (chaired by
John Rather) evaluating a host of potential approaches to mitigation
of an impending hazard should an asteroid be found to be on a
collision course with Earth (Rather et al. 1992).

During the 1990s, numerous scientific and engineering
conferences have been held worldwide concerning the impact hazard
(including one held at United Nations headquarters, Remo 1997) and
public interest groups were established in several nations, mostly
associated with the Spaceguard Foundation
(http://spaceguard.ias.rm.cnr.it/SGF/). Despite official notice
being taken by several national and international entities (e.g. the
Council of Europe), little serious attention has yet been given by
governments to evaluation of the NEO hazard or preparations for
dealing it (NEO = Near Earth Objects, including comets in addition to
NEAs). NASA, in collaboration with the U.S. Air Force, is the major
supporter of NEO research, with a few million dollars per year
devoted almost solely to the use of existing telescopes to search
for, and find by 2008, 90% of the NEAs larger than 1 km diameter
(http://neo.jpl.nasa.gov). In late 2000, a task force recommended
that the British government consider taking initial steps to support
efforts to research the impact hazard (Atkinson 2000;
http://www.nearearthobjects.co.uk/index.cfm); in late February 2001,
however, the government responded not with concrete action but only
promising to study the matter further and formulate an international
approach to the issue.

Other major elements of the impact hazard remain
unaddressed. Searches for comets and for smaller NEAs are in their
infancy. And little or no serious, official actions have been taken
by governments to be prepared to respond to any announcement of a
specific impact threatened in the years or decades ahead. For
example, Dr. Brian Marsden, who directs the International
Astronomical Union’s Minor Planet Center (where most astronomical
data concerning NEOs is cataloged:
http://cfa-www.harvard.edu/cfa/ps/mpc.html), recently said that he
had no idea who in the United States government would be
receptive to serious information he might have one day about an
impending impact. Surely some agencies would be interested, but
communication pathways, responsibilities, and implementation plans
have yet to be established.

This White Paper has been supported primarily by a
Presidential Discretionary Internal Research and Development grant
from Southwest Research Institute. Its purpose is to outline
elements of a systematic approach, with various options, for dealing
with the full breadth of the impact hazard — starting with issues
about discovery of potentially dangerous bodies, proceeding through
societal issues about evaluating the hazard and taking appropriate
advance measures, to actual mitigation of potentially threatening
impactors. We conclude with some recommendations that might lead to
a more comprehensive and balanced approach for twenty-first-century
society to take toward a very real, if low probability, threat that
could conceivably doom everyone we know and everything we care about.

DETECTION AND IMPACT EFFECTS (omitted here)

EVALUATION AND WARNING (omitted here)

MITIGATION (omitted here)

RECOMMENDATIONS

Our primary recommendation is that much broader groups of
people need to be educated about impact hazard issues, beyond the
superficial and often incorrect impressions they may have gotten from
their chief exposures to these matters: exaggerated/retracted news
stories about impact predictions and “near misses,” and movies like
“Armageddon.” A much broader segment of the technical community,
beyond astronomers and space engineers, needs to appreciate and
become familiar with technical aspects of this hazard. These
segments include the natural hazards community and experts in risk
assessment, meteorological storms, seismicity, climate modelling,
etc. In addition, public officials responsible for mitigation of
(and response to) emergencies and disasters need to understand the
basic attributes of the impact hazard. These include the
chains-of-command in the military and in the law-enforcement/civil
defense infrastructures.

Research, planning, and preparation need to commence now,
although it remains to be determined how far such activities should
go, given the low probabilities of having to address any real, major
impacts in our lifetimes. We believe that several issues need to be
addressed in the near future.

* The notification system (concerning a predicted potential impact)
needs to be cleaned up, expanded, and officially adopted and
implemented.

* Official clearinghouse/s for the best information need do be
developed (potential nuclei for such functions, including fledgling
web sites or analogous capabilities, already exist at Jet Propulsion
Laboratory, NOAA, Spaceguard Foundation, and the IAU Minor Planet
Center, among others).

* Serious connections need to be developed with the hazard
mitigation community, including agencies like FEMA.

* More objective approaches to communications need to be developed
to minimize misunderstanding of this hazard, which is so mismatched
to our personal experience base (extreme rarity or low chances of
happening vs. extreme potential consequences). In other words, the
Torino Impact Hazard Scale needs to be further developed, extended,
distributed, and explained.

* Official international channels for exchanging information about
NEO hazard-related issues and events need to be developed.

* Within the United States, an interagency approach, and assignment
of responsibilities, for dealing with the NEO hazard needs to be
developed; the Global Change Program may provide a template.
Analogous steps need to be developed in other nations and to
coordinate among nations.

* Education about the NEO hazard would be facilitated by conducting
a high-visibility, international conference on the NEO hazard,
emphasizing the non-astronomical, non-NEO-deflection issues that have
so far been treated as backwater concerns in previous NEO hazard
conferences. Perhaps a newsletter should be instituted.

* Given widespread interest in extending the Spaceguard search down
to bodies much smaller than the 1 km goal of the U.S. search efforts,
a thorough evaluation of ground- vs space-based approaches needs to
be made. Although spacebased efforts are usually vastly more
expensive, they have advantages that may balance the costs in some
cases; in other cases, the cost of spacebased efforts may not be
relevant (e.g. the searches may be piggy-backed onto other endeavors
that pay most of the costs).

* We consider the case of comets to be astonishingly intractable
(they are difficult to detect, there is a short time between
detection and impact so the object can’t be studied carefully, a
comet may be difficult or time-consuming to get to so it may not be
possible to “blast” it until it is almost here, a comet’s motion is
difficult to predict, and the structural nature of comets is poorly
known — they break-up independently and unpredictably). So we
recommend more detailed study of the nature of comets and of cometary
detection/mitigation strategies. At a minimum, we must quickly
assess how large a part of the impact hazard comets are.

* Chemical rockets may have quite wide applicability to deflection
scenarios; we recommend more study of that technology.

* In certain cases of attempted mitigation, disruption is more
likely than deflection. More research needs to be done in this area,
including studies of the potential consequences of disruption.

* All of these recommendations are predicated on a political
decision about the importance of the NEO hazard and about the
level-of-effort that should be expended in addressing it. The
technical community needs to identify potential criteria (beyond
simple comparisons of death rates from various hazards) for making
this judgement. We recommend that official, objective study/ies by
bodies like the National Research Council be done for this purpose.
Ultimately, society’s decision about how seriously to address the
impact hazard will have to involve broad segments of the public,
beyond the technical community.

REFERENCES (omitted here)

TABLE (omitted here)

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PROPOSED DAWN MISSION TO CERES & VESTA

from Chris Russell

Community Forum – March 11 on Dawn: A Discovery Mission to Vesta and Ceres

NASA has selected the proposed Dawn Discovery mission for a concept
study leading to a Step 2 proposal. Dawn uses solar electric
propulsion to fly to both Vesta and Ceres orbiting each for a period
of nine months. The spacecraft carries a framing camera, a mapping
spectrometer, a gamma ray/neutron spectrometer, a laser altimeter and
a magnetometer. Vesta is a dry, differentiated asteroid with a
basaltic crust and is the presumed parent body of the HED meteorites.
Ceres appears to be wet and have less distinct features. It has no
known associated meteorites. It has been postulated that Vesta
accreted dry and Ceres wet and that the water kept Ceres cool enough
to avoid differentiation. Thus these two asteroidal neighbors
represent two quite different end members of solar system evolution.

The top level science objectives, the measurement suite, and the
science team were approved during the Step 1 selection process. Over
the next several months the Dawn team will demonstrate to NASA that
we can safely achieve those objectives within the constraints of the
Discovery program. It is the intent of the Dawn science team to
engage the scientific community throughout the mission, with
community forums on our plans as we build the spacecraft and
instruments, and with participating scientist programs and data
analysis programs when we are obtaining data. The first community
forum will be held in Houston, TX on Sunday, March 11, 2001 from 1:00
to 4:00 p.m. in Admiral Room A at the Hilton Nassau Bay Hotel across
from the Johnson Space Center. The purpose of this meeting is both to
inform the community of our plans and to initiate meaningful
interactions as we execute the various mission phases. If you wish to
make a formal presentation, please contact amcglynn@igpp.ucla.ed!
u by March 1, 2001.

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NEO News is an informal compilation of news and opinion dealing with
Near Earth Objects (NEOs) and their impacts. These opinions are the
responsibility of the individual authors and do not represent the
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