Image: Vesta
NASA's Dawn spacecraft obtained this image of the giant asteroid Vesta with its framing camera on July 24, from a distance of about 3,200 miles (5,200 kilometers). The set of three overlapping craters toward the left side of the image is known informally as "the Snowman."
updated 8/1/2011 1:18:58 PM ET 2011-08-01T17:18:58

A NASA spacecraft orbiting the huge asteroid Vesta is beaming home images that reveal the giant space rock like never before, showing its battered and pockmarked surface in stunning detail.

The new photos from the Dawn probe, which NASA unveiled Monday, include the spacecraft's first full-frame view of the entire asteroid and should help astronomers understand how the space rock formed in the early solar system, researchers said.

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"We could not imagine the detail we're seeing and the processes that we're seeing," Chris Russell, Dawn's principal investigator at UCLA, said during a briefing on Monday. [See Dawn's latest photos of asteroid Vesta]

Vesta revealed
The detailed images of Vesta's surface were taken from a distance of about 3,200 miles (5,200 kilometers), using Dawn's framing camera. The pictures were snapped for navigation purposes as the spacecraft prepares to begin its scientific observations.

The images map the entire space rock, which turns on its axis once every five hours and 20 minutes, researchers said. NASA unveiled the new images as part of the buildup toward Dawn's one-year science mission at Vesta. [How NASA's Dawn Asteroid Mission Works (Infographic)]

"As the mission progresses, we'll be taking data at higher and higher resolution that will enable us to understand surface processes and interior processes better," Russell said.

The $466 million Dawn spacecraft entered orbit around Vesta on July 15. Vesta, the brightest asteroid in our solar system, is the second-largest object in the main asteroid belt between Mars and Jupiter. The space rock measures about 330 miles (530 kilometers) across.

Dawn will map Vesta at three different, and increasingly lower, orbits. During this process, the spacecraft will collect information on the elemental composition of Vesta's surface and its mass distribution, in addition to gathering gravity data and radio telemetry.

These measurements will help astronomers understand Vesta's formation history, which should also shine a light on the building blocks of the early solar system, researchers said.

Mapping an asteroid
Early photos of Vesta zeroed in on intriguing features on the rock's surface, including the boundary between the day and night sides, but these new images provide a much closer look at the surface features at the asteroid's two poles.

"The south pole area looks smoother, certainly different and less cratered than the northern hemisphere," said Holger Sierks, a member of Dawn's framing camera team at the Max Planck Society in Germany.

Vesta's heavily cratered northern hemisphere exhibits visible dark and light patches, something that members of the science team are eager to see in closer detail. "We don't know what the dark spots mean to us, but we will find out when we get the higher-resolution images from lower orbit," Sierks said.

The images also revealed elongated and deep grooves with many craters in the northern hemisphere, a find that surprised the science team.

"Those grooves are really neat," Russell said. "We saw those really early and they puzzled us and pleased us at the same time. You see those craters, with the black-and-white debris streaming down in them. Why such a great color contrast or albedo contrast on that material? It's not something I'm familiar with. We're going to learn a lot about this body."

Vesta's polar regions
In 2007, the Hubble Space Telescope turned its focus to Vesta, and those images revealed a massive crater, measuring 285 miles (456 kilometers) across, in the asteroid's southern hemisphere. The expansive crater was caused by an ancient collision, researchers said, and the Dawn spacecraft is now getting an even better look at the scar left by the impact, including a large central peak in the region. [Video - Vesta: The Planet That Never Was]

The science team is keen to investigate features on the crater's rim in order to glean information about the violent event. Furthermore, the grooves detected in the northern hemisphere could be markers of how intense the force was from the ancient collision, Russell said.

"[We're] really anxious to look at the north pole to see how that energy focused through the body, and what it did to the north," he added.

Dawn's close observations of Vesta will help astronomers understand the early days of the solar system, the asteroid belt, as well as the processes that formed and shaped rocky planets like Earth, Russell said.

"Now that we are in orbit around one of the last unexplored worlds in the inner solar system, we can see that it's a unique and fascinating place," Marc Rayman, Dawn's chief engineer and mission manager at NASA's Jet Propulsion Laboratory, said in a statement.

Double-asteroid mission
NASA's Dawn mission is the first prolonged visit to a large asteroid. The spacecraft is expected to take detailed photos of Vesta.

"We have been calling Vesta the smallest terrestrial planet," Russell said in a statement. "The latest imagery provides much justification for our expectations. They show that a variety of processes were once at work on the surface of Vesta and provide extensive evidence for Vesta's planetary aspirations."

Due to Vesta's large size, many astronomers classify it as a protoplanet, saying it would have continued to develop into a rocky planet like Earth or Mars if Jupiter's gravity had not wreaked havoc in the asteroid belt long ago.

Although Dawn has already been gathering some science data, the mission's intensive collection of information is expected to begin this month.

Image: "Snowman"
This image, captured by the Dawn spacecraft on July 24, focuses on a set of three craters on Vesta that have been nicknamed "Snowman" by the camera team's members.

"The new observations of Vesta are an inspirational reminder of the wonders unveiled through ongoing exploration of our solar system," said Jim Green, planetary division director at NASA Headquarters in Washington.

After spending a year at Vesta, Dawn will leave its orbit to travel to the asteroid Ceres, which is the largest body in the main asteroid belt. Ceres measures about 590 miles (950 kilometers) across and is so large that it is considered to be a dwarf planet. Dawn is expected to arrive at Ceres in February 2015.

NASA's Dawn mission is expected to return close-up views of Ceres, which should allow scientists to compare it to Vesta. Unlike the drier and more evolved Vesta, Ceres is considered to be more primitive and wet, possibly harboring water ice, researchers said.

The Dawn spacecraft launched in September 2007 and has since traveled more than 1.7 billion miles (2.7 billion km).

You can follow staff writer Denise Chow on Twitter @denisechow. Follow for the latest in space science and exploration news on Twitter @Spacedotcomand on Facebook.

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Gallery: The new solar system

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Photos: Month in Space: January 2014

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  1. Southern stargazing

    Stars, galaxies and nebulas dot the skies over the European Southern Observatory's La Silla Paranal Observatory in Chile, in a picture released on Jan. 7. This image also shows three of the four movable units that feed light into the Very Large Telescope Interferometer, the world's most advanced optical instrument. Combining to form one larger telescope, they are greater than the sum of their parts: They reveal details that would otherwise be visible only through a telescope as large as the distance between them. (Y. Beletsky / ESO) Back to slideshow navigation
  2. A balloon's view

    Cameras captured the Grandville High School RoboDawgs' balloon floating through Earth's upper atmosphere during its ascent on Dec. 28, 2013. The Grandville RoboDawgs’ first winter balloon launch reached an estimated altitude of 130,000 feet, or about 25 miles, according to coaches Mike Evele and Doug Hepfer. It skyrocketed past the team’s previous 100,000-feet record set in June. The RoboDawgs started with just one robotics team in 1998, but they've grown to support more than 30 teams at public schools in Grandville, Mich. (Kyle Moroney / AP) Back to slideshow navigation
  3. Spacemen at work

    Russian cosmonauts Oleg Kotov, right, and Sergey Ryazanskiy perform maintenance on the International Space Station on Jan. 27. During the six-hour, eight-minute spacewalk, Kotov and Ryazanskiy completed the installation of a pair of high-fidelity cameras that experienced connectivity issues during a Dec. 27 spacewalk. The cosmonauts also retrieved scientific gear outside the station's Russian segment. (NASA) Back to slideshow navigation
  4. Special delivery

    The International Space Station's Canadian-built robotic arm moves toward Orbital Sciences Corp.'s Cygnus autonomous cargo craft as it approaches the station for a Jan. 12 delivery. The mountains below are the southwestern Alps. (NASA) Back to slideshow navigation
  5. Accidental art

    A piece of art? A time-lapse photo? A flickering light show? At first glance, this image looks nothing like the images we're used to seeing from the Hubble Space Telescope. But it's a genuine Hubble frame that was released on Jan. 27. Hubble's team suspects that the telescope's Fine Guidance System locked onto a bad guide star, potentially a double star or binary. This caused an error in the tracking system, resulting in a remarkable picture of brightly colored stellar streaks. The prominent red streaks are from stars in the globular cluster NGC 288. (NASA / ESA) Back to slideshow navigation
  6. Supersonic test flight

    A camera looking back over Virgin Galactic's SpaceShipTwo's fuselage shows the rocket burn with a Mojave Desert vista in the background during a test flight of the rocket plane on Jan. 10. Cameras were mounted on the exterior of SpaceShipTwo as well as its carrier airplane, WhiteKnightTwo, to monitor the rocket engine's performance. The test was aimed at setting the stage for honest-to-goodness flights into outer space later this year, and eventual commercial space tours.

    More about SpaceShipTwo on PhotoBlog (Virgin Galactic) Back to slideshow navigation
  7. Red lagoon

    The VLT Survey Telescope at the European Southern Observatory's Paranal Observatory in Chile captured this richly detailed new image of the Lagoon Nebula, released on Jan. 22. This giant cloud of gas and dust is creating intensely bright young stars, and is home to young stellar clusters. This image is a tiny part of just one of 11 public surveys of the sky now in progress using ESO telescopes. (ESO/VPHAS team) Back to slideshow navigation
  8. Fire on the mountain

    This image provided by NASA shows a satellite view of smoke from the Colby Fire, taken by the Multi-angle Imaging SpectroRadiometer aboard NASA's Terra spacecraft as it passed over Southern California on Jan. 16. The fire burned more than 1,863 acres and forced the evacuation of 3,700 people. (NASA via AP) Back to slideshow navigation
  9. Where stars are born

    An image captured by NASA's Spitzer Space Telescope shows the Orion Nebula, an immense stellar nursery some 1,500 light-years away. This false-color infrared view, released on Jan. 15, spans about 40 light-years across the region. The brightest portion of the nebula is centered on Orion's young, massive, hot stars, known as the Trapezium Cluster. But Spitzer also can detect stars still in the process of formation, seen here in red hues. (NASA / JPL-Caltech) Back to slideshow navigation
  10. Cygnus takes flight

    Orbital Sciences Corp.'s Antares rocket rises from NASA's Wallops Flight Facility on Wallops Island, Va, on Jan. 9. The rocket sent Orbital's Cygnus cargo capsule on its first official resupply mission to the International Space Station. (Chris Perry / NASA) Back to slideshow navigation
  11. A long, long time ago...

    This long-exposure picture from the Hubble Space Telescope, released Jan. 8, is the deepest image ever made of any cluster of galaxies. The cluster known as Abell 2744 appears in the foreground. It contains several hundred galaxies as they looked 3.5 billion years ago. Abell 2744 acts as a gravitational lens to warp space, brightening and magnifying images of nearly 3,000 distant background galaxies. The more distant galaxies appear as they did more than 12 billion years ago, not long after the Big Bang. (NASA / NASA via AFP - Getty Images) Back to slideshow navigation
  12. Frosty halo

    Sun dogs are bright spots that appear in the sky around the sun when light is refracted through ice crystals in the atmosphere. These sun dogs appeared on Jan. 5 amid brutally cold temperatures along Highway 83, north of Bismarck, N.D. The temperature was about 22 degrees below zero Fahrenheit, with a 50-below-zero wind chill.

    Slideshow: The Year in Space (Brian Peterson / The Bismarck Tribune via AP) Back to slideshow navigation
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