[meteorite-list] Planetary Defense Plans For Asteroids Form

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 30 Nov 2011 09:40:23 -0800 (PST)
Message-ID: <201111301740.pAUHeOSW027183_at_zagami.jpl.nasa.gov>

http://www.aviationweek.com/aw/generic/story.jsp?id=news/awst/2011/11/28/AW_11_28_2011_p51-395551.xml&headline=PlanetaryDefensePlansForAsteroidsForm&channel=space

Planetary Defense Plans For Asteroids Form
By Guy Norris
Aviation Week & Space Technology
Nov 29, 2011

Concepts for communicating the risks and managing the threat of asteroid
impacts will be considered by the United Nations following an expert
working group meeting in Colorado.

The Near-Earth Object (NEO) media/risk meeting came within days of a
300-meter (984-ft.)-plus-dia. asteroid passing between the Earth and the
Moon on Nov 8, and as NASA closed on additional congressional funding of
more than $20 million for an ongoing survey mission aimed at finding
objects posing a potential collision threat.

Although acknowledged as a statistically rare, low-probability event,
asteroid impacts are seen as potential global catastrophes. Now, with
1,265 asteroids currently listed as potentially hazardous to Earth and
with around 100 or more new potential impacts currently being flagged
each month by the NASA Jet Propulsion Laboratory's automated
collision-monitoring Sentry system, the threat is being taken
increasingly seriously by governments and space agencies.

According to NASA, as of Nov 3 8,421 NEOs have been discovered, of which
830 are asteroids with a diameter of approximately 1 km or larger. A NEO
is an asteroid or a comet with an orbit close to that of Earth in which
the perihelion (or nearest point to the Sun) is less than 1.3
astronomical units (1.3 times the distance from the Earth to the Sun).
Potentially hazardous NEOs are 500 ft. or so in diameter and follow
orbital paths that come within 4.65 million mi. (7.48 million km) of Earth.

The meeting, held at University of Colorado's Laboratory for Atmospheric
and Space Physics, was organized by the Secure World Foundation and
aimed at a draft report for the U.N. Action Team 14 working group on
NEOs. The team forms part of the U.N.'s Committee on the Peaceful Uses
of Outer Space Scientific and Technical Subcommittee, and will present
guidance to the U.N. working group at a NEO-mitigation meeting in
Vienna, in February 2012.

Following a review in June next year, final recommendations will form
the blueprint for possible U.N. action from 2013 onward. The working
group is studying setting up an information, analysis and warning
network (IAWN) to coordinate data about NEO detection, orbit analysis,
impact prediction and notifications. The Colorado meeting was focused on
IAWN communications, including protocols used by similar warning nets
dealing with natural disasters such as hurricanes and tsunamis, as well
as improving public education on the NEO phenomenon.

Parallel work is underway to set up a NEO Mission Planning and
Operations Group (MPOG) that will coordinate international space
agencies on the planning and conduct of missions to threatening
asteroids. The MPOG will be modeled on the inter-space agency group
established to monitor space debris.

The conference included discussion of communication strategies for
events ranging from those with almost no warning such as the TC3
asteroid which exploded over southern Sudan in 2008 less than 21 hr.
after being detected, to decades-long scenarios such as the Apophis
asteroid which could potentially impact Earth in 2036.

In particular, the meeting focused on effective ways of communicating
the reality of threats and evacuation notices to predicted impact zones
in short-term warning scenarios. For longer-term threats, the group
weighed the geopolitical implications of potential mitigation strategies
involving speeding up or slowing down an asteroid. By altering an
asteroid's speed, its trajectory could be altered to either miss the
Earth altogether or be deflected toward less-populated areas. Such
choices inevitably involve increasing the risk to certain nations and
regions, while decreasing it for others, raising enormous policy questions.

Social scientists, invited to advise the group, called for transparent
debate from agencies over both warnings and mitigation strategies.
Dennis Mileti, director emeritus of University of Colorado's National
Hazards Center, warned "the biggest issue will not be panic but getting
them to take your NEO warning seriously. Human beings need to
dichotomize risk. That's how they decide to do something about it or
not. Don't try and explain your science to the public."

Former Apollo astronaut and asteroid awareness trailblazer Russell
Schweickart warned greater efforts and survey systems are needed. "We
have many more objects that will be discovered. We're not running out of
objects, we're running out of capability of our telescopes." While
roughly 94% of the largest NEOs are believed to have been located,
"there are 60% still not detected in the 300-meter or so size," said
Schweickart, who is co-founder and past chairman of the B612 Foundation
dedicated to protecting Earth from asteroid strikes. Detection numbers
are even lower for smaller NEOs between 100 and 300 meters in diameter
with only 10% of the estimated population accounted for, while for the
smallest ones - like the approximately 50-meter asteroid that airburst
over Tunguska, Siberia, in 1908 - ?we're below 1% of total objects
discovered. When it comes to objects that can do serious damage we're
nowhere near a full inventory yet," he added.

NASA NEO Observations Program Executive Manager Lindley Johnson said
securing allocated NEO funding is "critical to continuation of our
existing survey programs like the radars for instance, and to do sorely
needed upgrades for the Arecibo (radio telescope) in particular - that has
suffered from a lack of funding over the years." Johnson added money
will also support analysis "to determine what the next generation survey
should be."

Options include new land-based telescope projects like the Atlas
(Asteroid Terrestrial-impact Last Alert System) and Large Synoptic
Survey Telescope as well as space-based systems. These could include
hosted payload-type concepts in which a staring array would be mounted
on the "backside of a commercial payload," scanning as it orbits the
Earth. Such schemes are less capable than a dedicated survey telescope,
but much more affordable. "We really need to ferret out the best
solution," said Johnson.
Received on Wed 30 Nov 2011 12:40:23 PM PST