Mercury's Debussy crater and environs, in the first photo ever taken by a spacecraft in orbit around Mercury.
(Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington)
NASA this afternoon released the first-ever photo of Mercury taken from a spacecraft in orbit around the innermost planet of the solar system.
The most arresting element of the photo is the rayed crater
Debussy, which lends to the overall image the
impression of the vine end of a cantaloupe after the vine
has been snapped off. Straight out to the left of
Debussy and much smaller, about halfway to the left border,
lies the crater Matabei "with its unusual dark rays," NASA says.
The space agency has seen Debussy and Matabei before.
What it hasn't ever seen until now is a region of
Mercury that lies in the darker bottom half of the image,
in the direction of the planet's south pole.
The photo comes from the Messenger spacecraft,
which took off from Earth in 2004 and which has taken
plenty of flyby photos of Mercury since 2008.
Earlier this month, Messenger became the first spacecraft to go
into orbit around Mercury.
And with that, scientists are hoping to get a much fuller
sense of the inhospitable
planet, addressing questions such as these: Why is Mercury,
the planet closest to the sun, so dense? How big
is the planet's core, and is the outer core really molten?
What are the unusual materials at its poles--could that
actually be ice?
In the six hours since snapping this image of Debussy and environs
at 2:20 a.m. PT with the Wide Angle
Camera of the Mercury Dual Imaging System, Messenger acquired
363 more images and began downloading
the data to researchers here at home.
NASA plans to release additional images tomorrow.
The spacecraft is still in what NASA refers to as the commissioning
phase of its mission, as Messenger and its instruments
get checked out. The science mission begins April 4 and is expected
to last at least a year and to generate more than 75,000 images.
