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Vesta vistas streaming in

Full-frame image of Vesta

NASA's Dawn spacecraft obtained this image of the giant asteroid Vesta with its framing camera on July 24, 2011. It was taken from a distance of about 5,200 kilometres. Dawn will spend a year orbiting the body. After that, the next stop on its itinerary will be an encounter with the dwarf planet Ceres.

  • Vesta is one of the largest asteroids
  • Dawn mission will spend a year investigating it
  • First close-up images now coming in

AFTER TRAVELLING NEARLY FOUR YEARS and 2.8 billion kilometres, NASA’s Dawn spacecraft has been captured by the Vesta’s gravity. The giant asteroid and its new companion are currently approximately 184 million kilometres from Earth.

The first spacecraft to orbit an object in the main asteroid belt, Dawn is now spiralling down towards its first of four intensive science orbits. That initial orbit of the rocky world—to begin on August 11, at an altitude of nearly 2,700 kilometres—will provide in-depth analysis of the asteroid.

Vesta, 530 kilometres wide, is the brightest object in the asteroid belt as seen from Earth and is thought to be the source of a large number of meteorites that fall to Earth.

Snowman craters on Vesta

A set of three craters, informally nicknamed 'Snowman' by the camera's team members, is located in the northern hemisphere of Vesta.

Craters on Vesta

Various craters are visible in this image of part of the southern equatorial region of the giant asteroid Vesta.

The smallest rocky ‘planet’

Images from Dawn’s framing camera, taken for navigation purposes and as preparation for scientific observations, are revealing the first surface details of the giant asteroid. These images go all the way around Vesta, since the giant asteroid turns on its axis once every five hours and 20 minutes.

“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,” said Marc Rayman, Dawn’s chief engineer and mission manager at NASA’s Jet Propulsion Laboratory.

Download a Vesta wallpaper image, 1024 x 1024 pixels.

“We have been calling Vesta the smallest terrestrial planet,” said Chris Russell, Dawn’s principal investigator at UCLA. “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.”

Here’s a short video showing the different faces of Vesta as it rotates:

“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.

Dawn launched in September 2007. Following a year at Vesta, the spacecraft will depart in July 2012 for Ceres, where it will arrive in 2015.

More information: NASA’s Dawn mission pages

Adapted from information issued by NASA. Images courtesy NASA / JPL-Caltech / UCLA / MPS / DLR / IDA.

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Dawn mission reaches asteroid Vesta

Artist's impression of the Dawn mission

The Dawn spacecraft has spent almost four years tracking down the asteroid Vesta, located in the main asteroid belt between Mars and Jupiter. (Note that this artist's impression is not intended to be accurate, as it shows both Vesta and Dawn's next destination, Ceres, in the one frame, as well as many other small asteroids. In reality, these rocky bodies are nowhere near each other.)

NASA’S DAWN SPACECRAFT has become the first probe ever to enter orbit around an object in the main asteroid belt between Mars and Jupiter.

Dawn will study the asteroid, named Vesta, for a year before departing for a second destination, a dwarf planet named Ceres, in July 2012. Observations will provide unprecedented data to help scientists understand the earliest chapter of our solar system. The data also will help pave the way for future human space missions.

“Today, we celebrate an incredible exploration milestone as a spacecraft enters orbit around an object in the main asteroid belt for the first time,” NASA Administrator Charles Bolden said.

“Dawn’s study of the asteroid Vesta marks a major scientific accomplishment and also points the way to the future destinations where people will travel in the coming years.”

“President Obama has directed NASA to send astronauts to an asteroid by 2025, and Dawn is gathering crucial data that will inform that mission,” he added.

Dawn image of Vesta

This image of Vesta was taken with Dawn's navigation camera on July 9, 2011, from a distance of 41,000 kilometres. Once science operations begin, we will see very high-resolution images of the asteroid's surface.

Entering orbit

The spacecraft relayed information to confirm it entered Vesta’s orbit, but the precise time this milestone occurred is unknown at this time.

The time of Dawn’s capture depended on Vesta’s mass and gravity, which only has been estimated until now. The asteroid’s mass determines the strength of its gravitational pull.

If Vesta is more massive, its gravity is stronger, meaning it pulled Dawn into orbit sooner. If the asteroid is less massive, its gravity is weaker and it would have taken the spacecraft longer to achieve orbit.

According to the Dawn Twitter feed, the spacecraft has achieved an orbit about 16,000 kilometres from Vesta.

With Dawn now in orbit, the science team can take more accurate measurements of Vesta’s gravity and gather more accurate timeline information.

More information — see our earlier story on the Dawn mission, complete with videos.

Adapted from information issued by NASA / JPL. Images courtesy NASA / JPL-Caltech / UCLA / MPS / DLR / IDA.

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Asteroid rendezvous nears

Dawn and Hubble images of Vesta

Already, Dawn's images of Vesta (left) are better even than the Hubble Space Telescope can obtain (right). The protoplanet Vesta is the second-most massive object in the main asteroid belt.

NASA’S DAWN SPACECRAFT is on track to begin the first extended visit to a large asteroid. The mission expects to go into orbit around Vesta on July 16 and begin gathering science data in early August.

Vesta is considered a protoplanet, or body that didn’t quite become a full-fledged planet. It lives in the main asteroid belt between Mars and Jupiter, and is thought to be the source of a large number of meteorites that fall to Earth.

After travelling nearly four years and 2.7 billion kilometres, Dawn is approximately 150,000 kilometres away from Vesta. When Vesta captures Dawn into its orbit on July 16, there will be approximately 16,000 kilometres between them. When orbit is achieved, they will be approximately 188 million kilometres away from Earth.

Artist's impression of the Dawn spacecraft

Artist's impression of the Dawn spacecraft

“The spacecraft is right on target,” said Robert Mase, Dawn project manager at NASA’s Jet Propulsion Laboratory. “We look forward to exploring this unknown world during Dawn’s one-year stay in Vesta’s orbit.”

Peeling back the layers

After Dawn enters Vesta’s orbit, engineers will need a few days to determine the exact time of capture. Unlike other missions where a dramatic, nail-biting propulsive burn results in orbit insertion around a planet, Dawn has been using its placid ion propulsion system to subtly shape its path for years to match Vesta’s orbit around the Sun.

Images from Dawn’s framing camera, taken for navigation purposes, show the slow progress toward Vesta. Made into a movie (below), they are about twice as sharp as the best images of Vesta from NASA’s Hubble Space Telescope, but the surface details Dawn will obtain are still a mystery.

“We can’t wait for Dawn to peel back the layers of time and reveal the early history of our Solar System,” said Christopher Russell, Dawn principal investigator, at UCLA.

During the initial reconnaissance orbit, at a distance of approximately 2,700 kilometres, the spacecraft will get a broad overview of Vesta with colour pictures and data in different wavelengths of reflected light.

The spacecraft will then move drop lower into a mapping orbit about 680 kilometres above the surface to systematically map the parts of Vesta’s surface illuminated by the Sun.

It will collect stereo images to see topographic highs and lows, acquire higher-resolution data to map rock types at the surface; and learn more about Vesta’s thermal properties.

Up close and personal

Dawn then will move even closer, to a low-altitude mapping orbit approximately 200 kilometres above the surface. The primary science goals of this orbit are to detect the by-products of cosmic rays hitting the surface and help scientists determine the many kinds of atoms there, and probe the protoplanet’s internal structure.

“We’ve packed our year at Vesta chock-full of science observations to help us unravel the mysteries of Vesta,” said Carol Raymond, Dawn’s deputy principal investigator at JPL.

Following a year at Vesta, the spacecraft will depart for its second destination, the dwarf planet Ceres, in July 2012.

As Dawn spirals away from Vesta, it will pause again at the high-altitude mapping orbit. Because the Sun’s angle on the surface will have progressed, scientists will be able to see previously hidden terrain while obtaining different views of surface features.

Dawn was launched in September 2007.

More information about Dawn:

http://www.nasa.gov/dawn

http://dawn.jpl.nasa.gov/

Follow the mission on Twitter:

http://www.twitter.com/NASA_Dawn

Adapted from information issued by NASA / JPL-Caltech. Images courtesy NASA / JPL-Caltech / UCLA / MPS / DLR / PSI and NASA / ESA / STScI / Umd.

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