NASA's First Pictures of Mercury Taken From Orbit

MESSENGER'S First Shot

Image courtesy NASA/Johns Hopkins/Carnegie

A spidery crater named for a French composer features in the very first picture MESSENGER took from orbit around Mercury, taken March 29 and released March 30.

Debussy Crater had been known since before MESSENGER's arrival, thanks to its brilliant appearance in Earth-based radar images of Mercury. But no spacecraft had seen Debussy in visible light until MESSENGER made a flyby on its way into orbit.

The new shot of the 50-mile-wide (80-kilometer-wide) crater is a composite of three out of eight images taken through different light filters. Combining images taken at multiple wavelengths can reveal changes across Mercury's surface, since different minerals reflect light in unique ways. A black-and-white version of this Mercury picture was released on March 29.

Published March 30, 2011

Mercury's Frozen North?

Image courtesy NASA/Johns Hopkins/Carnegie

Angled sunlight accentuates the craters of Mercury's north pole in a newly released picture from NASA's MESSENGER spacecraft. This particular section of the planet had never before been seen by scientists.

Although sunlit surface temperatures on Mercury can reach 800 degrees F (427 degrees C), at the poles Mercury has craters deep enough—that is, shady enough—to be perpetually cold.

Radar observations show that something in a few of those craters is oddly bright. One theory MESSENGER will investigate is whether the craters are filled with water ice—a very unexpected possibility for the planet closest to the sun.

(Related: "Moon Has a Hundred Times More Water Than Thought.")

Published March 30, 2011

Mercury Crater Closeup

Image courtesy NASA/Johns Hopkins/Carnegie

In addition to capturing previously unseen parts of Mercury, NASA's MESSENGER will image some of the planet's better known features—such as Debussy Crater (pictured)—in unprecedented detail.

Moving in an egg-shaped orbit, MESSENGER will pass closest to the planet's north pole, coming a mere 125 miles (200 kilometers) from the surface. Examining the planet's impact craters in detail will help scientists with one of the main goals of the mission: to piece together Mercury's geologic history.

Published March 30, 2011

Crescent Mercury

Image courtesy NASA/Johns Hopkins/Carnegie

In Roman mythology, Mercury was the fleet-footed messenger to the gods. But the MESSENGER spacecraft might seem to be anything but speedy, taking six years to reach Mercury.

The NASA spacecraft needed time to take advantage of gravity assists—using the gravitational pull of planets to slingshot itself into the right path for reaching Mercury's orbit. These maneuvers allowed engineers to change the craft's speed and direction without burning fuel.

MESSENGER made three flybys of Mercury as part of this process, collecting data—such as this October 2008 picture of the planet's sunlit crescent—that gave scientists a taste of what's to come from the orbital mission.

Published March 30, 2011