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Oct.
1, 2008: NASA's MESSENGER spacecraft is returning
to Mercury. On Monday, Oct. 6, 2008, the probe will conduct
the second of three
planned flybys and photograph most of Mercury's remaining
unseen surface.
At
closest approach MESSENGER will pass just 125 miles above
Mercury's cratered surface, taking more than 1200 pictures.
The flyby also will provide a critical gravity assist needed
for MESSENGER to become, in March 2011, the first spacecraft
to actually orbit the innermost planet.
Above:
A color image of Mercury's giant Caloris Basin recorded during
MESSENGER's first flyby on Jan. 14, 2008. [more]
During
MESSENGER's first flyby on Jan. 14, 2008, its cameras photographed
approximately 20 percent of Mercury's surface never before
seen by space probes. The spacecraft spotted ancient volcanoes
ringing Mercury's Caloris Basin, found that Mercury's magnetic
field is "alive" (generated by an active dynamo
in Mercury's core) and discovered a surprisingly rich plasma
nebula trapped in Mercury's magnetic field. And those were
just a few of the surprises; see Science@NASA's New
Discoveries at Mercury for details.
"This
second flyby will show us a completely new area of Mercury's
surface, opposite from the side of the planet we saw during
the first," said Louise M. Prockter, instrument scientist
for the spacecraft's Mercury Dual Imaging System at the Johns
Hopkins University Applied Physics Laboratory in Laurel, Md.
The second flyby is expected to yield even more surprises.
A laser altimeter on the spacecraft will measure the planet's
topography, allowing scientists, for the first time, to correlate
high-resolution topography measurements with high-resolution
images. At the same time, MESSENGER's sensors will analyze
the chemical and mineralogical composition of Mercury's surface.
Below:
Much of Mercury's surface is still unknown. This
map shows areas that will be covered by the second flyby of
MESSENGER on Oct. 6, 2008. Solid purple denotes places that
have never been photographed by a spacecraft before. [larger
image]
"We
will be able to do the first test of differences in the chemical
compositions between the two hemispheres viewed in the two
flybys," says Ralph McNutt, the mission's project scientist
at APL.
"The
results from MESSENGER's first flyby of Mercury settled debates
that were more than 30 years old," notes Sean C. Solomon,
the mission's principal investigator from the Carnegie Institution
of Washington. "This second encounter should uncover
even more information about the planet."
Stay
tuned to Science@NASA for results from the flyby.
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Editor: Dr.
Tony Phillips | Credit: Science@NASA
| more
information |
| The
MESSENGER project
is the seventh in NASA's Discovery Program of low-cost,
scientifically focused space missions. The Applied Physics
Laboratory designed, built and operates the spacecraft
and manages the mission for NASA. MESSENGER stands for
MErcury Surface, Space ENvironment, GEochemistry and
Ranging. The Discovery and New Frontiers Program Office
at the NASA Marshall Space Flight Center manages the
Discovery Program for NASA Headquarters.
New
Discoveries at Mercury (Science@NASA)
Dark
Halos Discovered on Mercury (Science@NASA)
Surprises
from Mercury (Science@NASA)
MESSENGER
is more than halfway through a 4.9-billion-mile journey
to enter orbit around Mercury that includes more than
15 trips around the sun. In addition to flying by Mercury,
the spacecraft flew past Earth in August 2005 and past
Venus in October 2006 and June 2007.
NASA's
Future: US
Space Exploration Policy |
|
