NASA Sending a MESSENGER to Mercury

From: Ron (baalke_at_earthlink.net)
Date: 07/15/04 

Date: 15 Jul 2004 10:19:33 -0700

http://www.jhuapl.edu/newscenter/pressreleases/2004/040715.htm

Media Contacts

Michael Buckley
Johns Hopkins University Applied Physics Laboratory
Phone: 240-228-7536
   or 443-778-7536
E-mail: michael.buckley@jhuapl.edu

Donald Savage
NASA Headquarters
202-358-1727
E-Mail: DSavage@hq.nasa.gov

NASA Sending a MESSENGER to Mercury
July 15, 2004

   NASA's first trip to Mercury in 30 years - and the closest look ever
at the innermost planet - starts in August with the predawn launch of
the MESSENGER spacecraft from Cape Canaveral Air Force Station, Fla.

   MESSENGER will conduct an in-depth study of the Sun's closest
neighbor, the least explored of the terrestrial ("rocky") planets that
also include Venus, Earth and Mars. After a scheduled 2:16 a.m. (EDT)
liftoff aboard a Delta II launch vehicle on Aug. 2 - the first day of a
13-day launch period - MESSENGER's voyage includes three flybys of
Mercury in 2008 and 2009 and a yearlong orbit of the planet starting in
March 2011.

   "Our missions to Mars and Venus have produced exciting data and new
theories about the processes that formed the inner planets," says
Orlando Figueroa, director of the Solar System Exploration Division at
NASA Headquarters, Washington. "Yet Mercury still stands out as a planet
with a fascinating story to tell. MESSENGER should complete the detailed
exploration of the inner solar system - our planetary backyard - and
help us to understand the forces that shaped planets like our own."

   MESSENGER (short for MErcury Surface, Space ENvironment,
GEochemistry, and Ranging) is only the second spacecraft to set sights
on Mercury; Mariner 10 sailed past it three times in 1974 and 1975 and
gathered detailed data on less than half the surface. Carrying seven
scientific instruments on its compact and durable composite frame,
MESSENGER will provide the first images of the entire planet. The
mission will also collect detailed information on the composition and
structure of Mercury's crust, its geologic history, the nature of its
thin atmosphere and active magnetosphere, and the makeup of its core and
polar materials.

   MESSENGER's science team will shape its investigation around several
questions, including: Why is Mercury - the densest planet in the solar
system - mostly made of iron? Why is it the only inner planet besides
Earth with a global magnetic field? How can the planet closest to the
Sun, with daytime temperatures near 840 degrees Fahrenheit, have what
appears to be ice in its polar craters?

   "For nearly 30 years we've had questions that couldn't be answered
until technology and mission designs caught up with our desire to go
back to Mercury," says Dr. Sean C. Solomon, MESSENGER principal
investigator, from the Carnegie Institution of Washington. "Now we are
ready. The answers to these questions will not only tell us more about
Mercury, but illuminate processes that affect all the terrestrial planets."

   Mercury's proximity to the Sun makes it both a fascinating subject
and an unprecedented mission design challenge. The Sun can be up to 11
times brighter than what we see on Earth and surface temperatures at
Mercury's equator can reach 450 degrees Celsius (about 840 degrees
Fahrenheit), but MESSENGER will operate at room temperature behind a
sunshade of heat-resistant ceramic fabric. The 1.2-ton spacecraft also
features a heat-radiation system and will pass only briefly over
Mercury's hottest regions, limiting exposure to the intense heat
bouncing back from the broiling surface.

   "We're doing something no one has ever tried before," says MESSENGER
Project Manager David G. Grant, of the Johns Hopkins University Applied
Physics Laboratory (APL), Laurel, Md. "After launch and a long trip
through the inner solar system, we still face the risky and difficult
job of orbiting the planet next to the Sun. The team is confident that
the spacecraft they designed, built and tested is ready for this journey
and its mission to Mercury."

   On a 4.9-billion mile (7.9-billion kilometer) journey that includes
15 loops around the Sun, the solar-powered MESSENGER will fly past Earth
once, Venus twice and Mercury three times before easing into orbit
around its target planet. The Earth flyby, a year after launch, and the
Venus flybys, in October 2006 and June 2007, use the pull of the
planets' gravity to guide MESSENGER toward Mercury's orbit. The Mercury
flybys in January 2008, October 2008 and September 2009 fine-tune and
slow MESSENGER's track while allowing the spacecraft to gather data
critical to planning the mission's orbit phase.

   The MESSENGER project is the seventh in NASA's Discovery Program of
lower-cost, scientifically focused space missions. Solomon leads the
mission as principal investigator; APL manages the mission for NASA's
Office of Space Science and designed, built and will operate the
MESSENGER spacecraft. MESSENGER's science instruments were built by APL;
NASA Goddard Space Flight Center, Greenbelt, Md.; University of
Michigan, Ann Arbor; and University of Colorado, Boulder. GenCorp
Aerojet, Sacramento, Calif., and Composite Optics Inc., San Diego,
provided MESSENGER's propulsion system and composite structure,
respectively.

   The MESSENGER science team draws expertise from APL; Brown
University, Providence, R.I.; Carnegie Institution of Washington;
Goddard Space Flight Center; Los Alamos National Laboratory, N.M.;
Massachusetts Institute of Technology, Cambridge; Northwestern
University, Evanston, Ill.; Southwest Research Institute, Boulder,
Colo.; University of Arizona, Tucson; University of California, Santa
Barbara; University of Colorado, Boulder; University of Michigan, Ann
Arbor; and Washington University, St. Louis.

   Additional information about MESSENGER is available on the Web at:
http://messenger.jhuapl.edu

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