New Photos: Mars' Biggest Moon Phobos Up Close
Mars' largest moon is an oblong cratered rock named after the Greek god of fear.
Yet the frightful moon Phobos is hiding fewer secrets after a recent close flyby from the European spacecraft Mars Express.
The European Space Agency's probe passed within 62 miles (100 kilometers) of the Martian moon Jan. 9.
The encounter produced a collection of new photographs that reveal the satellite's pockmarked surface, including a possible landing site for a planned Russian sample-return mission to the moon. While Mars Express snapped the photos on Jan. 9, the probe had to wait until completing a suite of other observations before beaming the Phobos views back to Earth, ESA officials said.
Phobos is one of two moons orbiting around the Red Planet; the other is Deimos (meaning "dread" in Greek).
There is some controversy over how the moons formed, but one idea is that they were born when a comet or asteroid slammed into Mars and rubble debris from the collision condensed into the moons.
Phobos will be the site of the planned Russian Phobos-Grunt mission, which will launch late this year or early 2012, and will send an unmanned lander to touch down on the surface of Phobos, collect a sample of dirt, and return it to Earth.
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The mission aims to study Phobos' geology and origin, and will search for signs of possible past or present microbial life on the moon.
Here's a look at the latest close-up photos of Phobos:
Mars Express launched in June 2003 and entered orbit around Mars in December 2003. It is scheduled to operate until at least the end of 2012.
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Clara Moskowitz is a science and space writer who joined the Space.com team in 2008 and served as Assistant Managing Editor from 2011 to 2013. Clara has a bachelor's degree in astronomy and physics from Wesleyan University, and a graduate certificate in science writing from the University of California, Santa Cruz. She covers everything from astronomy to human spaceflight and once aced a NASTAR suborbital spaceflight training program for space missions. Clara is currently Associate Editor of Scientific American. To see her latest project is, follow Clara on Twitter.