From: LARRY KLAES (ljk4_at_msn.com)
Date: Wed Jul 30 2003 - 09:06:53 PDT
----- Original Message -----
From: Ron Baalke - Mars Exploration Program
Sent: Friday, July 25, 2003 12:48 PM
Subject: Los Alamos Release New Maps Of Mars Water
Los Alamos releases new maps of Mars water
Contact: Nancy Ambrosiano, nwa_at_lanl.gov, (505) 667-0471 (03-101)
Contact: Jim Danneskiold, jdanneskiold_at_lanl.gov, (505) 667-1640
July 24, 2003
LOS ALAMOS, N.M. -- "Breathtaking" new
maps of likely sites of water on Mars showcase their
association with geologic features such as Vallis Marineris,
the largest canyon in the solar system.
The maps detail the distribution of water-equivalent
hydrogen as revealed by Los Alamos National
Laboratory-developed instruments aboard NASA's Mars
Odyssey spacecraft. In an upcoming talk at the Sixth
International Conference on Mars at the California Institute of
Technology, in Pasadena, Los Alamos space scientist Bill
Feldman and coworkers will offer current estimates of the
total amount of water stored near the Martian surface. His
presentation will be at 1:20 p.m., Friday, July 25.
For more than a year, Los Alamos' neutron spectrometer has
been carefully mapping the hydrogen content of the planet's
surface by measuring changes in neutrons given off by soil, an
indicator of hydrogen likely in the form of water-ice. The new
color maps are available at
"The new pictures are just breathtaking, the
water-equivalent hydrogen follows the geographic features
beautifully," said Feldman. "There's a lane of hydrogen-rich
material following the western slopes of the biggest
volcanoes in the solar system, a maximum reading sits right
on Elysium mons, and another maximum is in the deepest
canyon in the solar system."
The new maps combine images from the Mars Orbiter Laser
Altimeter (MOLA) on the Mars Global Surveyor with Mars
Odyssey spectrometer data through more than half a Martian
year of 687 Earth days. From about 55 degrees latitude to the
poles, Mars boasts extensive deposits of soils that are rich in
water-ice, bearing an average of 50 percent water by mass.
In other words, Feldman said, a typical pound of soil scooped
up in those polar regions would yield an average of half a
pound of water if it were heated in an oven.
The tell-tale traces of hydrogen, and therefore the presence
of hydrated minerals, also are found in lower concentrations
closer to Mars' equator, ranging from two to 10 percent water
by mass. Surprisingly, two large areas, one within Arabia
Terra, the 1,900-mile-wide Martian desert, and another on
the opposite side of the planet, show indications of relatively
large concentrations of sub-surface hydrogen.
Scientists are attracted to two possible theories of how all
that water got into the Martian soils and rocks.
The vast water icecaps at the poles may be the source. The
thickness of the icecaps themselves may be enough to bottle up
geothermal heat from below, increasing the temperature at the
bottom and melting the bottom layer of the icecaps, which then
could feed a global water table.
On the other hand, there is evidence that about a million years
or so ago, Mars' axis was tilted about 35 degrees, which might
have caused the polar icecaps to evaporate and briefly create
enough water in the atmosphere to make ice stable planet-wide. The
resultant thick layer of frost may then have combined chemically
with hydrogen-hungry soils and rocks.
"We're not ready yet to precisely describe the abundance and
stratigraphy of these deposits, but the neutron spectrometer shows
water ice close to the surface in many locations, and buried
elsewhere beneath several inches of dry soils," Feldman said.
"Some theories predict these deposits may extend a half mile or
more beneath the surface; if so, their total water content may be
sufficient to account for the missing water budget of Mars."
In fact, a team of Los Alamos scientists has begun a research
project to interpret the Mars Odyssey data and their ramifications
for the history of Mars' climate. The project is funded through
the Laboratory Directed Research and Development program - which
funds innovative science with a portion of the Laboratory's
operating budget - and seeks to develop a global Martian hydrology
model, using vast amounts of remote sensing data, topography maps
and experimental results on water loading of minerals.
Members of the Planetary Science team at Los Alamos working with
Feldman on the Odyssey project include Bruce Barraclough, David
Bish, Dorothea Delapp, Richard Elphic, Herbert Funsten, Olivier
Gasnault, David Lawrence, G. McKinney, Kurt Moore, Robert Tokar,
Thomas Prettyman, David Vaniman and Roger Wiens as well as Sylvestre
Maurice of the Observatoire Midi-Pyrénées (France), S.W.
Squyres of Cornell University, and Jeff Plaut of the Jet Propulsion
Los Alamos' neutron spectrometer, a more sensitive version of the
instrument that found water ice on the moon five years ago, is one
component of the gamma-ray spectrometer suite of instruments aboard
Odyssey. W.T. Boynton of the University of Arizona leads the
gamma-ray spectrometer team.
The neutron spectrometer looks for neutrons generated when cosmic
rays slam into the nuclei of atoms on the planet's surface, ejecting
neutrons skyward with enough energy to reach the Odyssey spacecraft
250 miles above the surface.
Elements create their own unique distribution of neutron energy - fast,
thermal or epithermal - and these neutron flux signatures are shaped
by the elements that make up the soil and how they are distributed.
Thermal neutrons are low-energy neutrons in thermal contact with the
soil; epithermal neutrons are intermediate, scattering down in energy
after bouncing off soil material; and fast neutrons are the
highest-energy neutrons produced in the interaction between high-energy
galactic cosmic rays and the soil.
By looking for a decrease in epithermal neutron flux, researchers can
locate hydrogen. Hydrogen in the soil efficiently absorbs the energy
from neutrons, reducing their flux in the surface and also the flux that
escapes the surface to space where it is detected by the spectrometer.
Since hydrogen is likely in the form of water-ice at high latitudes, the
spectrometer can measure directly, a yard or so deep into the Martian
surface, the amount of ice and how it changes with the seasons.
The Los Alamos expertise in neutron spectroscopy stems from longtime
nuclear nonproliferation work at the Laboratory, funded by the U.S.
Department of Energy's National Nuclear Security Administration. The
ability to measure and detect signatures of nuclear materials is a
vital component of the Laboratory's mission to reduce the threats
from weapons of mass destruction.
Mars Odyssey was launched from Cape Canaveral Air Force Station in
April 2001 and arrived in Martian orbit in late October 2001. During
the rest of the spacecraft's 917-day science mission, Los Alamos'
neutron spectrometer will continue to improve the hydrogen map and
solve more Martian moisture mysteries.
Jet Propulsion Laboratory, a division of the California Institute of
Technology in Pasadena, manages the Mars Odyssey mission for NASA's
Office of Space Science in Washington, D.C. Investigators at Arizona
State University in Tempe, the University of Arizona in Tucson and
NASA's Johnson Space Center, Houston, operate the science instruments.
Additional science partners are located at the Russian Aviation and
Space Agency and at Los Alamos National Laboratories, New Mexico.
Lockheed Martin Astronautics, Denver, the prime contractor for the
project, developed and built the orbiter. Mission operations are
conducted jointly from Lockheed Martin and from JPL.
Los Alamos National Laboratory is operated by the University of
California for the National Nuclear Security Administration (NNSA)
of the U.S. Department of Energy and works in partnership with NNSA's
Sandia and Lawrence Livermore national laboratories to support NNSA
in its mission.
Los Alamos develops and applies science and technology to ensure the
safety and reliability of the U.S. nuclear deterrent; reduce the
threat of weapons of mass destruction, proliferation and terrorism;
and solve national problems in defense, energy, environment and
This archive was generated by hypermail 2.1.6 : Wed Jul 30 2003 - 09:32:13 PDT