Status Report

NASA NEO News: Open Letter to Congress on Near Earth Objects

By SpaceRef Editor
July 28, 2003
Filed under , ,
NASA NEO News: Open Letter to Congress on Near Earth Objects
impact

July 8, 2003

Re: The Imperative to Address the Impact Threat From Near Earth Objects (NEOs)

Dear Members of Congress:

We write to you today as concerned citizens, convinced that the
time has come for our nation to address comprehensively the impact
threat from asteroids and comets. A growing body of scientific
evidence shows that some of these celestial bodies, also known as
Near Earth Objects (NEOs), pose a potentially devastating threat of
collision with Earth, capable of causing widespread destruction and
loss of life. The largest such impacts can not only threaten the
survival of our nation, but even that of civilization itself.

Although we are genuinely concerned about the NEO threat, none of
us is an alarmist. We know of no Near Earth Object currently on a
collision course with Earth, but science’s limited knowledge of the
NEO population cannot rule out that possibility. Base on current
information, a crisis response to these potential threats is not
warranted. That being said, however, based upon evidence of past
impacts and recent asteroid observations as well as the possible
consequences from just one relatively small NEO impact, business as
usual regarding this threat is simply no longer a responsible or
sensible course of action.

Studies indicate that, with the commitment of modest resources,
NEO impacts can likely be predicted and, with adequate warning, steps
taken to prevent them. Thanks to scientific advances and increased
awareness, we now have a historic opportunity to deal comprehensively
and effectively with the NEO threat. Doing so, however, will require
determined and coordinated action by Congress, the Executive Branch,
and the private sector to direct effective use of our nation’s
substantial scientific and technological capability.

U.S. and international academic conferences, as well as
Congressional hearings, have served to illuminate some aspects of the
NEO impact hazard. Here, we build upon this background and outline a
recommended course of action for Congress.

To address this potential threat, we strongly urge that each of
you take steps within your respective committee jurisdictions to
implement immediately the following recommendations (each
is discussed in more detail in the enclosure):.

1. NEO Detection: Expand and enhance this nation’s capability
to detect and to determine the orbits and physical characteristics
and physical characteristics of NEOs.

2. NEO Exploration: Expand robotic exploration of asteroids
and Earth-approaching comets. Obtain crucial follow up information on
follow-up on NEOs (required to develop an effective deflection
capability) by directing that U.S. astronauts again leave low-Earth
orbit . . . this time to protect life on Earth.

3. NEO Contingency and Response Planning: Initiate
comprehensive contingency and response planning for deflecting any
NEO found to pose a potential threat to Earth. In parallel, plan to
meet the disaster relief needs created by an impending or actual NEO
impact. U.S. government/private sector planning should invite
international cooperation in addressing the problems of NEO
detection, potential hazards and actual impacts.

Overview of Confirmed NEO Impacts and Recently Detected NEOs

– Sixty-five million years ago, a trillion-ton comet or asteroid
only about six miles across struck what is now Chicxulub on Mexico’’s
Yucatan Peninsula. That impact resulted in the extinction of at
least 75% of Earth’’s species, including the dinosaurs.

– Thirty-five million years ago, a comet or asteroid only
approximately 3 miles in diameter struck Earth in Chesapeake Bay,
about 120 miles southeast of Washington, D.C. That impact created a
crater some 50 miles wide, changed the courses of many modern rivers
and caused changes in ground-water aquifers that are still evident
today.

– Fifty thousand years ago, an asteroid just 150 feet in diameter,
weighing approximately 300,000 tons, and traveling at 40,000 miles
per hour struck Earth in what is today Arizona. Today, the crater
from that impact, even after weathering, is still nearly a mile wide
and 570 feet deep.

About a hundred years ago, on June 30, 1908, an object from space
appeared in the morning sky over western China. It plunged through
the atmosphere, glowing at a temperature of over 5,000 degrees F.
Streaking over central Russia, the object’’s passage produced a
deafening roar, preceded by a supersonic blast wave that leveled
trees and houses in its path. As reported in the newspaper Sibir,
this impact occurred early in the ninth hour of the morning. Near
the Stony Tunguska River, the object exploded in mid-air with an
energy greater than a 10-megaton nuclear blast. The explosion
devastated a region some 40 miles across, two-thirds the size of
Rhode Island. Only a few people were killed in this sparsely
populated region, but the story would have been very different if the
object had hit a few hours later over Europe instead of the Siberian
forest. The death toll in major cities such as St. Petersburg,
Helsinki, Stockholm or Oslo might have reached 500,000.

In 1947, also in Russia, in the Sikhote-Alin Mountains, northeast
of Vladivostok, a small meteor traveling at 31,000 miles per hour
struck Earth’s atmosphere, creating a fireball witnesses said was
brighter than the sun. One of the fragments left an impact crater 85
feet across and 20 feet deep.

In 1994, the world witnessed the devastating effects that a large
NEO impact could inflict on Earth. Astronomers who had observed the
breakup of comet Shoemaker-Levy 9 then tracked its headlong crash
into Jupiter, where it generated an explosion with an energy
equivalent to a billion megatons of TNT. The resulting dust cloud in
Jupiter’s atmosphere swelled larger than our own Earth; a similar
impact here would have destroyed our civilization and devastated life
on this planet. Shoemaker-Levy 9 was discovered just sixteen months
before it hit Jupiter, and its spectacular demise was a shot across
our bow — a reminder that comets also can strike Earth. Comets,
though less frequent visitors to Earth’’s vicinity than asteroids,
strike with much greater kinetic energy, and comprise a small but
significant part of the impact threat to Earth.

On January 7, 2002, the asteroid 2001 YB5 missed our planet by a
little more than twice the distance to the Moon. If this
300-yard-wide, stadium-sized object, discovered only 12 days before
its closest approach, had hit the Earth’’s continental landmasses, it
would have destroyed nearly everyone and everything in an area about
the size of New England. An ocean impact would also have spawned huge
tsunamis, with the potential for damage to coastal areas beyond
anything in historical experience.

The modest search efforts sponsored by the National Aeronautics
and Space Administration (NASA) and the Department of Defense have
detected a steady stream of close encounters. On June 14, 2002,
asteroid 2002 MN, an object about 100 yards in diameter, passed
within just 75,000 miles of Earth at a speed of over 23,000 miles per
hour. 2002 MN was detected by astronomers at the Lincoln Near Earth
Asteroid Research (LINEAR) search facility in New Mexico three days
after its closest approach to Earth. Had this object struck Earth, it
would have exploded with energy about equal to that of the 1908
Siberian impact near Tunguska.

On July 5, 2002, the LINEAR astronomers discovered another
object, designated 2002 NT7, estimated to be over a mile in diameter.
And in November 2002, astronomers discovered 2002 VU94, an NEO
estimated to be over two miles across. While both objects pose no
danger to Earth in the coming centuries, their recent discovery and
large size emphasize the fact that many large NEOs remain
undiscovered.

Scientists have realized for some time that Earth travels amid
a sea of similar objects, large and small. NASA stated last year in
Congressional testimony that we have detected only a little more than
half of all NEOs larger than a kilometer in diameter. Prudence
dictates that more be done to identify NEOs, and to obtain the
scientific information necessary to divert any sizable NEO found to
be on a collision course with Earth.

The NEO Threat

The latest NEO close approaches are typical of the two dozen such
encounters known to have occurred in the 20th Century. These are
only a small fraction of the actual number that have occurred; most
have gone completely undetected. Such approaches are commonplace in
our part of the solar system. The late planetary geologist Eugene
Shoemaker put it succinctly: Earth exists in an asteroid swarm.

We know that since 1937, at least 22 asteroids have approached
Earth more closely than did 2001 YB5, which missed by just twice the
distance to the Moon. Five of those objects were larger than 100
yards in diameter. According to NASA, there may be as many as
100,000 NEOs with diameters of 100 yards or larger. Of those
asteroids larger than 150 yards in diameter, about 250 are today
estimated to be potentially hazardous. The United States has very
limited capability to detect these smaller NEOs, which can
nevertheless inflict substantial damage upon striking Earth. There is
a significant probability (20%) of such an object colliding with the
Earth during the next century.

Although the annual probability of a large NEO impact on Earth is
relatively small, the results of such a collision would be
catastrophic. The physics of Earth’’s surface and atmosphere impose
natural upper limits on the destructive capacity of natural
disasters, such as earthquakes, landslides, and storms. By contrast,
the energy released by an NEO impact is limited only by the object’’s
mass and velocity. Given our understanding of the devastating
consequences to our planet and its people from such an event, (as
well as the smaller-scale but still-damaging effects from smaller NEO
impacts), our nation should act comprehensively and aggressively to
address this threat. America’’s efforts to predict, and then to avoid
or mitigate such a threat, should be at least commensurate with our
national efforts to deal with more familiar terrestrial hazards.

If space research has taught us anything, it is the certainty
that an asteroid or comet will hit Earth again. Impacts are common
events in Earth’’s history: scientists have found more than 150 large
impact craters on our planet’’s surface. Were it not for Earth’’s
oceans and geological forces such as erosion and plate tectonics, the
planet’’s impact scars would be as plain as those visible on the Moon.

Potential Misinterpretation of NEO Impacts

Even small NEO impacts in the atmosphere, on the surface, or at
sea create explosions that could exacerbate existing political
tensions and escalate into major international confrontations. For
example, an atmospheric impact in 2002 produced a large, highly
visible burst of light in the sky during the height of war tensions
between nuclear-armed countries India and Pakistan. That
high-altitude explosion happened to occur over the Mediterranean,
just a few thousand miles from their disputed border region. Had that
NEO impact occurred less than three hours earlier, it would have
detonated over southern Asia, where its misinterpretation as a
surprise attack could have triggered a deadly nuclear exchange. With
military and diplomatic tensions at their peak in other areas of
conflict in the world, the potential for a mistake is even greater
today.

Conclusion

For the first time in human history, we have the potential to
protect ourselves from a catastrophe of truly cosmic proportions. All
of us remember vividly the effect on our nation of terrorist strikes
using subsonic aircraft turned into flying bombs: thousands of our
citizens dead, and our economy badly shaken. Consider the
ramifications of an impact from a relatively small NEO: more than a
million times more massive than an aircraft, and traveling at more
than thirty times the speed of sound. If such an object were to
strike a city like New York, millions would die. In addition to the
staggering loss of life, the effects on the national and global
economy would be devastating. Recovery would take decades.

We cannot rely on statistics alone to protect us from
catastrophe; such a strategy is like refusing to buy fire insurance
because blazes are infrequent. Our country simply cannot afford to
wait for the first modern occurrence of a devastating NEO impact
before taking steps to adequately address this threat. We may not
have the luxury of a second chance, for time is not necessarily on
our side. If we do not act now, and we subsequently learn too late of
an impending collision against which we cannot defend, it will not
matter who should have moved to prevent the catastrophe . . . only
that they failed to do so when they had the opportunity to prevent it.

Our nation, our families, and others around the globe deserve our
best efforts to protect against the NEO impact threat. We urge the
Congress to call on this nation’’s ready supply of talents and
energies to responsibly address this threat. Our international
partners also should be called upon to help meet this challenge, but
the United States has a compelling responsibility to lead the way.
Preventing an NEO impact is a vital mission for our nation’’s space
program and for the American people. For the first time since Apollo,
our astronauts should once again leave low-Earth orbit and journey
into deep space, this time to protect life on our home planet.

We strongly recommend your prompt attention and action to address
this too-long-ignored threat to the security of America and to the
world. The accompanying recommendations are prudent and concrete
steps each of you can now take to safeguard our nation. Your timely
and effective response can protect the people of the United States
and the world from the real threat posed by Near Earth Objects.

Sincerely,

  • Dr. Harrison H. Schmitt
  • Dr. Carolyn S. Shoemaker
  • David H. Levy
  • Dr. John Lewis
  • Dr. Neil D. Tyson
  • Dr. Freeman Dyson
  • Dr. Richard P. Hallion
  • Dr. Thomas D. Jones
  • Bruce Joel Rubin
  • Dr. Lucy Ann McFadden
  • Erik C. Jones
  • Marc Schlather
  • William E. Burrows

Enclosure: NEO Detection, Impact Prevention and Mitigation Recommendations

NEO Detection, Impact Prevention and Mitigation Recommendations

After assessing the nature and scope of the NEO impact threat,
and in consultation with many leading authorities on space issues, we
are recommending three steps to deal with the problem. The first
will increase our nation’s ability to detect an NEO impact in time,
the second will lay the groundwork for deflecting such an object, and
the third will help mitigate the consequences of an actual NEO
impact. Such steps would entail a relatively modest commitment of
resources, an investment warranted by the potential consequences of
misjudging the NEO impact threat to Earth.

Recommendation #1:
Immediately Increase the Scope of and Funding for NEO Detection

The United States is currently engaged in a search for all NEOs
greater than 0.62 miles (a kilometer) in diameter. The effort is
producing results, but only a few dozen researchers are funded to
conduct this basic survey. Resources committed to this work have been
very modest and not commensurate with the potential threat; thus,
additional investment in search programs is both appropriate and
prudent. A dramatic improvement in the rate at which asteroids and
comets are discovered would likely result if the United States were
to increase the current level of funding, now at about $3.5 million
per year, to at least $20 million annually.

We recommend that Congress take the following measures to enhance
the search for NEOs:

* Increase search activities for detection of NEOs 0.62 miles (1
kilometer) in diameter and larger. Researchers estimate that only
one-half of such NEOs have been located. The pace of identification
should be accelerated. Support for Southern Hemisphere search
activities may further increase the discovery rate and should be
expanded. Even when NASA achieves its current goal of identifying 90%
of large NEOs, the undiscovered remainder will, of course, still pose
a potential hazard. Congress should direct NASA to pursue the search
for all such objects to statistical completion.

* Expand the search effort to include detection and tracking of NEOs
smaller than 0.62 miles (1 kilometer). NEOs such as 2002 MN (about a
hundred yards across) are not currently the target of any formal
search program. Rather, they are discovered as by-products of the
search for larger objects. Because an impact of even a relatively
small NEO could still destroy a major city, the United States should
establish the goal of predicting any close approach to Earth by any
asteroid larger than 200 yards in diameter.

* Increase funding for the Minor Planet Center (MPC) to $1 million
annually. The MPC is responsible for the collection, computation and
dissemination of the characteristics and orbits of asteroids and
comets. As the central international clearinghouse for tracking NEOs,
it should be funded at a level more commensurate with its important
role in understanding and addressing the NEO threat.

* Provide funding for more and better instrumentation and additional
follow-up observations. In addition to maintaining existing optical
and radar search programs, NASA should be given the added resources
and mandate to enhance the instrumentation dedicated to NEO detection
and to respond to NEO discoveries with more detailed observations.
Such radar and spectroscopic observations are vital to refine
asteroid orbits and determine an NEO’s general composition.

Recommendation #2:
Expand Current NEO Exploration Programs

Given the real probability of an asteroid or comet impact, our
nation must understand NEO characteristics well enough to develop
practical methods to deflect them. for diversion. Without adequate
knowledge of the composition and mechanical properties of such
objects, developing diversion diversion strategies will be
problematic at best and fatally ineffective at worst.

Therefore, we recommend that the United States take the following action:

* Mount additional near-term robotic missions to selected asteroids
and Earth-approaching comets. By visiting NEOs in our own
“neighborhood,” we can determine their composition, measure their
structural and mechanical properties, and provide the knowledge
essential to preventing impacts on Earth by similar objects.

* Begin planning now to send explorers to nearby asteroids and
Earth-approaching comets. Developing the capability to send
astronauts to NEOs (on round-trips lasting just a few months) is the
next logical human spaceflight goal for the United States. Such
expeditions will help provide protection to Earth, serve as an
insurance policy against future NEO impacts and, in the process,
expand our ability to understand and use the vast and beneficial
resources of space. Ideally, these voyages should immediately follow
the completion of the International Space Station; planning for them
should start now.

Our nation should once again send its astronauts beyond low-Earth
orbit . . . this time to protect our planetary home.

Recommendation #3: Develop NEO Contingency and Response Plans

Just as the federal government plans appropriate responses to
disasters such as hurricanes and earthquakes, it should prepare
contingency plans for dealing with an NEO impact. The government
should begin planning now to deflect any NEO found to pose a
potential threat to Earth. It should also plan to meet emergency
response and disaster relief needs created by an impending or actual
NEO impact. This government/private sector planning should include
international coordination to address the issues of NEO detection,
potential hazards and actual impacts.

To guide essential contingency planning, we recommend the following:

* Establish an Interagency NEO Task Force to address the NEO Impact
Threat: This Task Force should be composed of senior representatives
from appropriate government agencies: Department Of Homeland
Security; Department of Defense; Department of State; Department of
Energy; NASA; Federal Emergency Management Agency; National Science
Foundation; Office of Science and Technology Policy; and the National
Research Council. The Task Force should also include appropriate
necessary representatives from industry and academia. It should be
assigned responsibilities for guiding NEO impact contingency planning
through an NEO Impact Response Center (see below), including
identification, monitoring and analysis, international coordination
of NEO search efforts, impact response and mitigation, and deflection
strategies and technology.

* Establish an NEO Impact Response Center: This Center should be
assigned responsibilities to — (1) collate accurate information from
all available existingsources on the threat potential of any
potentially hazardous NEOs; (2) distribute such information and
analysis to public agencies, both in the United States and overseas;
(3) develop establish and implement contingency plans, to include the
actions required to deflect an NEO if that becomes necessary; and (4)
ensure that an unexpected impact is not misinterpreted as an attack
on any country.

The Center should collect astronomical and technical data about NEOs
provided by existing research and search efforts. More importantly,
it should verify this information and provide authoritative analysis
to the President (and Secretary of Homeland Security), and the
relevant committees of the Congress in the event of a projected NEO
impact. The Center would enable U.S. civil and military authorities
to develop the appropriate responses to an impact prediction and
disseminate impact information worldwide.


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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
positions of NASA, the International Astronomical Union, or any other
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dmorrison@arc.nasa.gov. For additional information, please see the
website http://impact.arc.nasa.gov. If anyone wishes to copy or
redistribute original material from these notes, fully or in part,
please include this disclaimer.

SpaceRef staff editor.