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MESSENGER Mission News
December 5, 2011
|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).
New MESSENGER Mosaics Available for Download
MESSENGER mosaics that can be explored interactively using the ACT-REACT QuickMap 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 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.
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 entered orbit about Mercury on March 17, 2011 (March 18, 2011 UTC), to begin a yearlong study of its target planet. 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.
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