[meteorite-list] MESSENGER Team Presents Latest Mercury Findings at AGU Fall Meeting

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue, 6 Dec 2011 12:02:55 -0800 (PST)
Message-ID: <201112062002.pB6K2tL6021182_at_zagami.jpl.nasa.gov>

http://messenger.jhuapl.edu/news_room/details.php?id=190

MESSENGER Mission News
December 5, 2011

MESSENGER Team Presents Latest Mercury Findings at AGU Fall Meeting

Members of the MESSENGER team will present a broad range of findings
from the spacecraft's orbital investigation of Mercury during the 2011
Fall Meeting of the American Geophysical Union (AGU), which takes place
this week, December 5-9, in San Francisco. In 63 oral and poster
presentations spanning 13 technical sessions, team scientists will
report on the analysis and interpretation of observations made by
MESSENGER's instruments since the spacecraft entered orbit around
Mercury in March 2011.

The majority of the MESSENGER papers will be given in three special
sessions on December 8. Those papers will report new findings on the
topography and gravity field of Mercury's northern hemisphere, Mercury's
internal structure and dynamics, the elemental composition of Mercury's
surface, the variation of Mercury's surface spectral reflectance,
Mercury's distinctive hollows, plains volcanism on Mercury,
characteristics of impact craters on Mercury, deformation of Mercury's
surface, Mercury's internal magnetic field, the structure and
variability of Mercury's exosphere, the structure and dynamics of
Mercury's magnetosphere, energetic particles and plasma ions in
Mercury's vicinity, and Mercury's interplanetary environment.

MESSENGER Principal Investigator Sean Solomon will also deliver AGU's
Shoemaker Lecture to provide an overview of all that's been discovered
about the innermost planet.

Many of these presentations will be available by video on demand. To
view the sessions, visit the AGU Fall Meeting web page at
http://sites.agu.org/fallmeeting/scientific-program/sessions-on-demand/
and click on the appropriate session at the scheduled time (Pacific time).

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New MESSENGER Mosaics Available for Download

MESSENGER mosaics that can be explored interactively using the ACT-REACT
QuickMap
<http://messenger-act.actgate.com/msgr_public_released/react_quickmap.html>
software tool are now available for downloading. These mosaics were
created using images from the first two months of MESSENGER's orbital
operations, released by NASA's Planetary Data System on September 8,
2011. The mosaic shown here
<http://messenger.jhuapl.edu/gallery/sciencePhotos/pics/mdis_v6_750nm_5000mpp_eqc_stretch.png>
is at 5 km/pixel, but this mosaic is also available at resolutions of
2.5 km/pixel, 1 km/pixel, and 250 m/pixel. High-resolution mosaics of
the polar regions are also available.

All mosaics are available for downloading at the Global Mosaics page
<http://messenger.jhuapl.edu/the_mission/mosaics.html>.

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MESSENGER Executes Final Orbit Correction Maneuver of Primary Science Mission

The MESSENGER spacecraft successfully completed a fifth orbit-correction
maneuver today to lower MESSENGER's periapsis altitude from 442 to 200
kilometers and decrease the orbital period from 12 hours to 11 hours and
47 minutes.

MESSENGER was 102 million kilometers (63.4 million miles) from Earth
when the 291-second maneuver began at 11:08 a.m. EST. Mission
controllers at The Johns Hopkins University Applied Physics Laboratory
(APL) in Laurel, Md., verified the start of the maneuver about 5 minutes
and 40 seconds later, when the first signals indicating spacecraft
thruster activity reached NASA's Deep Space Network tracking station
outside Goldstone, Calif.

This orbit-correction maneuver, the final one planned for the primary
orbital phase of the mission, was executed to keep orbital parameters
within desired ranges for optimal scientific observations. MESSENGER's
orbital velocity was changed by a total of 22.2 meters per second (49.7
miles per hour) to make the corrections essential for continuing the
planned measurement campaigns.

"The successful completion of this burn marks a significant milestone on
the MESSENGER project," says MESSENGER Systems Engineer Eric Finnegan of
APL. "The propulsion system has now completed all major maneuver
requirements for the primary mission. Given the complexity of this
propulsion system and the challenges of the trajectory, this is a major
achievement for the APL and Aerojet design and mission operation teams."

------------------------------------------------------------------------

MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and
Ranging) is a NASA-sponsored scientific investigation of the planet
Mercury and the first space mission designed to orbit the planet closest
to the Sun. The MESSENGER spacecraft launched on August 3, 2004, and
after flybys of Earth, Venus, and Mercury will start a yearlong study of
its target planet in March 2011. Dr. Sean C. Solomon, of the Carnegie
Institution of Washington, leads the mission as Principal Investigator.
The Johns Hopkins University Applied Physics Laboratory built and operates
the MESSENGER spacecraft and manages this Discovery-class mission for NASA.
Received on Tue 06 Dec 2011 03:02:55 PM PST