[meteorite-list] Tracing the Big Picture of Mars' Atmosphere (ExoMars)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Fri, 27 Aug 2010 08:42:47 -0700 (PDT)
Message-ID: <201008271542.o7RFgl9I021920_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2010-280

Tracing the Big Picture of Mars' Atmosphere
Jet Propulsion Laboratory
August 26, 2010

One of the instruments on a 2016 mission to orbit Mars will provide
daily maps of global, pole-to-pole, vertical distributions of the
temperature, dust, water vapor and ice clouds in the Martian atmosphere.

The joint European-American mission, ExoMars Trace Gas Orbiter, will
seek faint gaseous clues about possible life on Mars. This instrument,
called the ExoMars Climate Sounder, will supply crucial context with its
daily profiling of the atmosphere's changing structure.

The European Space Agency and NASA have selected five instruments for
ExoMars Trace Gas Orbiter. The European Space Agency will provide one
instrument and the spacecraft. NASA will provide four instruments,
including ExoMars Climate Sounder, which is coming from NASA's Jet
Propulsion Laboratory, Pasadena, Calif.

Two of the other selected instruments are spectrometers -- one each from
Europe and the United States -- designed to detect very low
concentrations of methane and other important trace gases in the Martian
atmosphere.

"To put the trace-gas measurements into context, you need to know the
background structure and circulation of the atmosphere," said JPL's Tim
Schofield, principal investigator for the ExoMars Climate Sounder. "We
will provide the information needed to understand the distribution of
trace gases identified by the spectrometers. We'll do this by
characterizing the role of atmospheric circulation and aerosols, such as
dust and ice, in trace-gas transport and in chemical reactions in the
atmosphere affecting trace gases."

The ExoMars Climate Sounder is an infrared radiometer designed to
operate continuously, day and night, from the spacecraft's orbit about
400 kilometers (about 250 miles) above the Martian surface. It can pivot
to point downward or toward the horizon, measuring temperature, water
vapor, dust and ices for each 5-kilometer (3-mile) increment in height
throughout the atmosphere from ground level to 90 kilometers (56 miles)
altitude.

Schofield and his international team have two other main goals for the
investigation, besides aiding in interpretation of trace-gas detections.

One is to extend the climate mapping record currently coming from a
similar instrument, the Mars Climate Sounder, on NASA's Mars
Reconnaissance Orbiter, which has been working at Mars since 2006. The
orbital geometry of the Mars Reconnaissance Orbiter mission enables this
sounder to record atmospheric profiles only at about 3 p.m. and 3 a.m.
during the Martian day, except near the poles. The ExoMars Trace Gas
Orbiter will fly an orbital pattern that allows the spacecraft to
collect data at all times of day, at all latitudes.

"We'll fill in information about variability at different times of day,
and we'll add to the number of Mars years for understanding year-to-year
variability," said Schofield. "The most obvious year-to-year change is
that some years have global dust storms and others don't. We'd like to
learn whether there's anything predictive for anticipating the big dust
storms, and what makes them so variable from year to year."

A third research goal is to assist future landings on Mars by supplying
information about the variable density of the atmosphere. At a chosen
landing site, atmospheric density can change from one day to the next,
affecting a spacecraft's descent.

"We want to provide background climatology for what to expect at a given
site, in a given season, for a particular time of day, and also nearly
real-time information for the atmospheric structure in the days leading
up to the landing of a spacecraft launched after 2016," said Schofield.

The 2016 ExoMars Trace Gas Orbiter is the first in a series of planned
Mars mission collaborations of the European Space Agency and NASA. A
variable presence of small amounts of methane in the Martian atmosphere
has been indicated from orbital and Earth-based observations. A key goal
of the mission is to gain a better understanding of methane and other
trace gases that could be evidence about possible biological activity.
Methane can be produced both biologically and without life.

Besides the two spectrometers and the climate sounder, the orbiter's
selected instruments include two NASA-provided imagers: a
high-resolution, stereo, color imager, and a wide-angle, color, weather
camera. The orbiter will also serve as a communications relay for
missions on the surface of Mars and will carry a European-built
descent-and-landing demonstration module designed to operate for a few
days on the Mars surface. JPL, a division of the California Institute of
Technology, manages NASA's roles in the mission.

Jia-Rui C. Cook/Guy Webster 818-354-0850/354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
jia-rui.c.cook at jpl.nasa.gov/guy.webster at jpl.nasa.gov

2010-280
Received on Fri 27 Aug 2010 11:42:47 AM PDT