[meteorite-list] MESSENGER Completes Its First Extended Mission at Mercury

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 18 Mar 2013 15:56:34 -0700 (PDT)
Message-ID: <201303182256.r2IMuYwr009168_at_zagami.jpl.nasa.gov>

http://messenger.jhuapl.edu/news_room/details.php?id=237

MESSENGER Mission News
March 18, 2013

MESSENGER Completes Its First Extended Mission at Mercury

On March 17, 2013, MESSENGER successfully completed its year-long first
extended mission in orbit about Mercury, building on the groundbreaking
scientific results from its earlier primary mission. Today the team is
poised to embark on a second extended mission that promises to provide
new observations of Mercury's surface and interior at unprecedented
spatial resolution and of the planet's dynamic magnetosphere and
exosphere at high time resolution during the peak and declining phase of
the current solar cycle.

"NASA is currently considering a second extension to mission operations
and until the formal decision is made has asked that we continue to
operate the spacecraft and its scientific instruments," says MESSENGER
Project Manager Helene Winters of the Johns Hopkins University Applied
Physics Laboratory (APL) in Laurel, Maryland.

During its first extended mission, MESSENGER completed 12 specialized
measurement campaigns that led to new discoveries about surface
volatiles on Mercury, the duration of volcanism, the evolution of
long-wavelength topography, the nature of localized regions of enhanced
exospheric density, the effect of the solar cycle on Mercury's
exosphere, and Mercury's energetic electrons.

Among the most recent results was confirmation of the long-held theory
that the planet harbors abundant water ice and other frozen volatile
materials within its permanently shadowed polar craters.

If approved by NASA, a second extended mission would seek answers to
still further questions, each stimulated by findings from the primary
mission and first extended mission, including:

    * What active and recent processes have affected Mercury's surface?

    * How has the state of stress in Mercury's crust evolved over time?

    * How have compositions of volcanic materials on Mercury varied with
      time?

    * What are the characteristics of volatile sequestration in
      Mercury's north polar region?

    * What are the consequences of precipitating ions and energetic
      electrons at Mercury?

    * How do Mercury's exosphere and magnetosphere respond to extreme
      solar wind conditions near and following solar maximum?

    * What novel insights into Mercury's thermal and crustal evolution
      can be obtained from high-resolution measurements made at low
      altitudes?

A possible second extended mission is among the topics MESSENGER team
members will be discussing on March 20 in a session
<http://www.lpi.usra.edu/meetings/lpsc2013/pdf/sess303.pdf> at the 44th
Lunar and Planetary Science Conference in The Woodlands, Texas.

"Mercury has been revealing its many secrets, but each discovery has led
to new puzzles," adds MESSENGER Principal Investigator Sean Solomon, of
Columbia University's Lamont-Doherty Earth Observatory. "We now have a
healthy spacecraft in orbit around a planet that will not be visited by
spacecraft again for more than 10 years. Our scientific plans for a
second extended mission build on past discoveries, can be accomplished
with planned orbital observations, span an unprecedented phase of the
solar cycle, and include extraordinarily low-altitude campaigns that
will offer spectacular new views of Mercury's surface and near-surface
environment. We hope that NASA will support the continued investigation
of the most enigmatic of the inner planets."

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

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
and entered orbit about Mercury on March 17, 2011 (March 18, 2011 UTC),
to begin a yearlong study of its target planet. MESSENGER's extended
mission began on March 18, 2012, and ended one year later. A possible
second extended mission is currently under evaluation by NASA. Dr. Sean
C. Solomon, the Director of Columbia University's Lamont-Doherty Earth
Observatory, 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 Mon 18 Mar 2013 06:56:34 PM PDT