Scientists
are sifting through their first new views of the planet Mercury in more than
three decades thanks to images beamed home by NASA's MESSENGER probe.
The
car-sized spacecraft zipped
past Mercury in a Monday flyby and is relaying more than 1,200 new images and
other data back to eager scientists on Earth.
"Now it's
time for the scientific payoff," MESSENGER principal investigator Sean Solomon
of the Carnegie Institution of Washington told SPACE.com after the flyby.
"It's just a complete mix of results that we're going to get."
In one new
image, released today, the planet's stark surface is shown peppered with small
craters, each less than a mile (1.6 km) in diameter and carved into an area
about 300 miles (482 km) across. MESSENGER used its narrow-angle camera to
photograph the scene, which is dominated by a large, double-ringed crater
dubbed Vivaldi after the Italian composer. While the crater was last seen by NASA's
Mariner 10 probe, MESSENGER's camera observed it with unprecedented detail,
researchers said.
Another new
view reveals the first look at the half of Mercury left uncharted by Mariner
10.
"It is
already clear that MESSENGER's superior camera will tell us much that could not
be resolved even on the side of Mercury viewed by Mariner's vidicon camera in
the mid-1970s," said MESSENGER researchers at the Johns Hopkins University's
Applied Physics Laboratory (JHUAPL) in a Wednesday statement. JHUAPL engineers
built MESSENGER for NASA and are managing its $446 million mission for the
space agency.
MESSENGER,
short for MErcury Surface, Space ENvironment, GEochemistry, and Ranging,
trained its seven instruments on Mercury on Monday for the first of three
planned flybys to guide itself toward a March 18, 2011, arrival into orbit
around the small, rocky planet. The mission is the first to visit Mercury since
1975, when Mariner 10 made its third and final swing past the planet.
"These
flybys are the only time that we fly by the surface of Mercury at low latitude
near the equator," Solomon said.
MESSENGER
is due to make a second rendezvous at Mercury in October, then swing by on
third pass in September 2009. The probe launched in August 2004 and flew by
Earth once and Venus twice during its 4.9 billion-mile (7.9 billion-kilometer)
trek toward Mercury orbit.
During
Monday's flyby, MESSENGER skimmed just 124 miles (200 km) above Mercury's
surface and snapped photographs of about half of the estimated 55 percent of
the planet that remained uncharted after Mariner 10's mission. In addition to
imagery, the probe is expected to return a wealth of new observations made by
its seven instruments to scrutinize Mercury's
surface composition, magnetic field, tenuous atmosphere, unusually high
density and other features.
"It will
take upwards of a week to get all of the data off the spacecraft," said
MESSENGER systems engineer Eric Finnegan before the Monday flyby. "Within that
week, the scientists will start receiving some of the images of the flyby and
processing that data."
Researchers
hope MESSENGER's findings will not only answer
long-standing questions about Mercury, but also shed new light on how
planets formed in the early days of the solar system. The probe will generate
complete maps of Mercury's surface, measure the planet's gravitational field
and search for any hints of ice at the bottom of permanently shadowed craters
near the poles as part of its mission.
"I just can't
wait," said Mark Robinson, a MESSENGER science team member at the University of Arizona. "I want to see what's around the corner."
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