[meteorite-list] Cornell Astronomer Tells Congress It Should Spend $125 Million For New Telescope To Detect Earth-Threatening Asteroids

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:06:55 2004
Message-ID: <200210040129.SAA13989_at_zagami.jpl.nasa.gov>

http://www.news.cornell.edu/releases/Oct02/Burns.earthimpacts.deb.html

Cornell astronomer tells Congress it should spend $125 million for
new telescope to detect Earth-threatening asteroids

EMBARGOED FOR RELEASE: WEDNESDAY, OCT. 3, 2002, AT 10 A.M. ET

Contact: David Brand
Office: 607-255-3651
E-mail: deb27_at_cornell.edu

WASHINGTON, D.C. -- A Cornell University astronomer told a House of
Representatives space subcommittee today that Washington should spend
$125 million for a new type of ground-based telescope that could
detect hundreds of asteroids and numerous comets that pose a
potential threat to the Earth from space over the next century.

Reporting on a government-commissioned review of solar system
exploration by some of the nation's leading scientists, he said that
the new wide-field telescope is needed to produce a weekly digital
map of the visible sky in order to track space rocks called
near-Earth objects (NEOs), the great majority of which have yet to be
discovered. There is, he said, a 1 percent probability of an impact
with Earth by a 300-meter-diameter (350 yards) body in the next 100
years, resulting in many deaths and widespread devastation.

The astronomer, Joseph Burns, the Irving Porter Church Professor of
Engineering and professor of astronomy at Cornell, in Ithaca, N.Y.,
is a member of the Solar System Exploration Decadal Survey's steering
group. His comments to the House Science Committee panel came during
his presentation of a small portion of the findings of the survey,
which had been commissioned by the National Research Council (NRC) at
the behest of NASA.

The impact of an object of this size, he said, would deliver a
thousand megatons of energy and (assuming an average population
density of 10 people per square kilometer) result in a million
fatalities. The damage caused by an impact near a city or into
coastal water would be "orders of magnitude higher." As of November
2001, he said, 340 objects larger than a kilometer had been cataloged
as "potentially hazardous asteroids," and the number of new comets
with impact potential "is large and unknown."

Burns quoted a section of the survey report (titled New Frontiers in
the Solar System): "Important scientific goals are associated with
the NEO populations, including their origin, fragmentation and
dynamical histories, and compositions and differentiation. These and
other scientific issues are also vital to the mitigation of the
impact hazard, as methods of deflection of objects potentially on
course for an impact with Earth are explored. Information especially
relevant to hazard mitigation includes knowledge of the internal
structures of near-Earth asteroids and comets, their degree of
fracture and the presence of large core pieces, the fractal
dimensions of their structures, and their degree of cohesion or
friction."

However, Burns said, a survey for potentially threatening NEOs
"demands an exacting observational strategy," and to locate most of
the objects with diameters as small as 300 meters requires a
capability a hundred times better than that of existing survey
telescopes. Because NEOs spend only a fraction of each orbit in
Earth's neighborhood, "repeated observations over 10 years would be
required to explore the full volume of space occupied by these
objects." Such a survey, said Burns, would discover NEOs at the rate
of about 100 per night and obtain astrometric information on the much
larger, and growing, number of NEOs that it had already discovered.
(Astrometry is the technique used to calculate the orbits of NEOs and
assess the hazard that each poses to Earth.) "Astrometry at weekly
intervals would ensure against losing track of these fast-moving
objects in the months and years after discovery," said Burns.

To do this, he said, requires construction of an entirely new type of
telescope, the large-aperture synoptic survey telescope (LSST) "to
survey the entire sky relatively quickly, so that periodic maps can
be constructed that will reveal not only the positions of target
sources, but their time variability as well," the Cornell astronomer
said. The LSST would be a 6.5-metre-class, very-wide-field (3
degrees) telescope that would produce a digital map of the visible
sky every week, and carry out an optical survey of the sky far deeper
than any previous survey.

Such a telescope, he said, "could locate 90 percent of all near-Earth
objects down to 300 meters in size, enable computations of their
orbits and permit assessment of their threat to Earth. It would
discover and track objects in the Kuiper Belt, a largely unexplored,
primordial component of our solar system."

A previous NRC astronomy and astrophysics survey also had recommended
the building of an LSST. The new survey, however, recommends that
NASA and NSF pay equally for the telescope's construction and
operations, said Burns. The new survey, he said, projects the costs
of the LSST at $83 million for capital construction and $42 million
for data processing and distribution over five years of operation,
for a total cost of $125 million. Routine operating costs, including
a technical and support staff of 20 people, are estimated at
approximately $3 million per year, he said.

The construction of the LSST, Burns told the legislators, "would
provide a central, federal-sponsored location" for tracking the
potentially threatening objects.

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Received on Thu 03 Oct 2002 09:29:24 PM PDT