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LOS ANGELES - In an unusual move, NASA is reviewing a recent decision by an agency head to scrap a mission to orbit two asteroids. The Dawn project was canceled on March 2, five months after it was put on standdown because of cost overruns and technical problems. NASA's unusual step to review Dawn's termination came after the Jet Propulsion Laboratory in Pasadena, which manages the mission, presented new evidence, the space agency said in a statement. It's the first time in recent memory that a NASA center has challenged a headquarters decision on a canceled mission, said NASA spokeswoman...

Icy world found inside asteroid Ron Cowen New observations of Ceres, the largest known asteroid, suggest that frozen water may account for as much as 25 percent of its interior. If this is true, the volume of ice on Ceres would be greater than that of all the fresh water on Earth. CERES SERIES. This sequence of Hubble images reveals a bright spot of unknown origin on Ceres during a quarter-turn of the asteroid's 9-hour rotation. Thomas, et al., NASA The evidence comes from Hubble Space Telescope images showing that the 930-kilometer-wide asteroid is smooth and almost perfectly round. Simulations...

Explanation: That bright, ruddy star you've recently noticed rising just after sunset isn't a star at all. That's Mars, the Red Planet. Mars is now near its 2014 opposition (April 8) and closest approach (April 14), looping through the constellation Virgo opposite the Sun in planet Earth's sky. Clearly outshining bluish Spica, alpha star of Virgo, Mars is centered in this labeled skyview from early April, that includes two other solar system worlds approaching their opposition. On the left, small and faint asteroid Vesta and dwarf planet Ceres are seen near star Tau Virginis. But you'll just have to imagine...

| The discovery of mysterious rocks on the brightest large asteroid in the solar system, Vesta, deepens the mystery surrounding the huge object's origins, researchers say. Vesta is the second-largest asteroid in the solar system. The 330-mile-wide (530-kilometer) protoplanet is also the brightest large asteroid, with a surface about three times more luminous than Earth's moon.

Explanation: That bright star you've recently noticed rising just after sunset isn't a star at all. It's Jupiter, the solar system's ruling gas giant. Bright Jupiter is nearing its December 3rd opposition when it will stand in Taurus, opposite the Sun in planet Earth's sky. Clearly outshining yellowish Aldebaran, alpha star of Taurus, Jupiter is centered in this skyview from November 14th, also featuring the Pleiades and Hyades star clusters, familiar celestial sights as the northern hemisphere winter approaches. Sliding your cursor over the image will label the scene and identify two other solar system worlds approaching their opposition in...

Explanation: Next stop: Ceres. Last week the robotic Dawn spacecraft ended its year-long mission to asteroid Vesta, becoming the first spacecraft ever to visit this far off world located between Mars and Jupiter, in the Solar System's main asteroid belt. Many of the best images taken by Dawn at Vesta have been compiled into the above encompassing view. Vesta shows evidence of being a leftover from the early years of our Solar System, a building block for rocky planets like Earth. Vesta's ancient surface shows heavy cratering and long troughs likely created by huge impacts. The minor planet's low gravity...

“I have announced this star as a comet, but since it is not accompanied by any nebulosity and, further, since its movement is so slow and rather uniform, it has occurred to me several times that it might be something better than a comet. But I have been careful not to advance this supposition to the public.” -Giuseppe Piazzi, discoverer of Ceres, the first Asteroid Out beyond Mars, but not quite out as far as Jupiter, a collection of thousands of rocky objects, ranging in size from pebbles all the way up to the size of Texas, lies the...

Explanation: Now shining in eastern skies at dawn, bright planets Venus and Jupiter join the Pleiades star cluster in this sea and sky scape, recorded earlier this week near Buenos Aires, Argentina. Venus dominates the scene that includes bright star Aldebaran just below and to the right. The planets are easy to spot for early morning risers, but this sky also holds two of our solar system's small worlds, Vesta and Ceres, not quite bright enough to be seen with the unaided eye. The digital camera's time exposure just captures them, though. Their positions are indicated when you put your...

Explanation: What would it be like to fly over the asteroid Vesta? Animators from the German Aerospace Center recently took actual images and height data from NASA's Dawn mission currently visiting Vesta to generate such a virtual movie. The above video begins with a sequence above Divalia Fossa, an unusual pair of troughs running parallel over heavily cratered terrain. Next, the virtual spaceship explores Vesta's 60-km Marcia Crater, showing numerous vivid details. Last, Dawn images were digitally recast with exaggerated height to better reveal Vesta's 5-km high mountain Aricia Tholus. Currently, Dawn is rising away from Vesta after being close...

Explanation: These colorful images are of thin slices of meteorites viewed through a polarizing microscope. Part of the group classified as HED (Howardite, Eucrite, Diogenite) meteorites for their mineral content, they likely fell to Earth from 4 Vesta, the mainbelt asteroid currently being explored by NASA's Dawn spacecraft. Why are they thought to be from Vesta? Because the HED meteorites have visible and infrared spectra that match the spectrum of that small world. The hypothesis of their origin on Vesta is also consistent with data from Dawn's ongoing observations. Excavated by impacts, the diogenites shown here would have originated deep...

Explanation: These colorful images are of thin slices of meteorites viewed through a polarizing microscope. Part of the group classified as HED meteorites for their mineral content (Howardite, Eucrite, Diogenite), they likely fell to Earth from 4 Vesta, the mainbelt asteroid currently being explored by NASA's Dawn spacecraft. Why are they thought to be from Vesta? Because the HED meteorites have visible and infrared spectra that match the spectrum of that small world. The hypothesis of their origin on Vesta is also consistent with data from Dawn's ongoing observations. Excavated by impacts, the diogenites shown here would have originated deep...

Explanation: Asteroid Vesta is home to some of the most impressive cliffs in the Solar System. Pictured above near the image center is a very deep cliff running about 20 kilometers from top to bottom. The image was taken by the robotic Dawn spacecraft that began orbiting the 500-kilometer space rock earlier this year. The topography of the scarp and its surroundings indicates that huge landslides may have occurred down this slope. The scarp's origin remains unknown, but parts of the cliff face itself must be quite old as several craters have appeared in it since it was created. Dawn...

Explanation: What created the circular structure around the south pole of asteroid Vesta? Pictured above, the bottom of the second largest object in the asteroid belt was recently imaged for the first time by the robotic Dawn satellite that arrived last month. A close inspection of the 260-meter resolution image shows not only hills and craters and cliffs and more craters, but ragged circular features that cover most of the lower right of the 500-kilometer sized object. Early speculation posits that the structure might have been created by a collision and coalescence with a smaller asteroid. Alternatively, the features might...

Explanation: Get out your red/blue glasses and float next to 4 Vesta. A 500 kilometer diameter world, Vesta lies in the main asteroid belt between the orbits of Mars and Jupiter. This stereo anaglyph was constructed from two separate images recorded on July 24 by the just arrived Dawn spacecraft's framing camera with a resolution of about 500 meters per pixel. The 3D view features Vesta's newly discovered terrain, including long equatorial ridges and troughs and the prominent string of three craters at the upper right dubbed Snowman. Highlighted in 3D, steep sides of many of the craters show streaks...

Explanation: Why is the northern half of asteroid Vesta more heavily cratered than the south? No one is yet sure. This unexpected mystery has come to light only in the past few weeks since the robotic Dawn mission became the first spacecraft to orbit the second largest object in the asteroid belt between Mars and Jupiter. The northern half of Vesta, seen on the upper left of the above image, appears to show some of the densest cratering in the Solar System, while the southern half is unexpectedly smooth. Also unknown is the origin of grooves that circle the asteroid...

Explanation: What does the surface of asteroid Vesta look like? The brightest asteroid in the Solar System and the object which takes up about 10 percent of the entire mass of the main asteroid belt had never been seen up close before. Over the past few weeks, however, the robotic Dawn spacecraft became the first spacecraft ever to approach Vesta. A few days ago, just after attaining orbit, Dawn took the above image. Early images show Vesta to be an old and battered world, covered with craters, bulges, grooves, and cliffs. Studying Vesta may give clues to the formative years...

The asteroid Vesta may be the brightest asteroid in the solar system, but it remains shrouded in mystery. When NASA's Dawn probe enters into orbit around Vesta on July 15 — the first spacecraft to visit the 330-mile-wide (530-kilometer) protoplanet — it promises to shed light on the many enigmas of the second-largest body in the asteroid belt. NASA launched the $466 million Dawn mission in 2007, with Vesta as the first (but not last) stop. The Dawn probe is also expected to visit Ceres, the largest asteroid in the solar system, but only after unlocking the secrets of Vesta....

If you were riding with NASA’s Dawn spacecraft, now cruising the asteroid belt between Mars and Jupiter, you would see a brightening new point of light against the starry background. This is Vesta, your immediate destination. Artist rendition of Dawn gathering spectral data from Vesta. Scientists have estimated that Dawn will enter Vesta’s gravitational field on July 16, 2011, and begin taking data when it descends to an altitude of 2700 km from the surface. Dawn’s first image of Vesta, the second-largest object in the asteroid belt, still has fewer pixels than those of it taken by the Hubble Space...

This image shows the first, unprocessed image obtained by NASA's Dawn spacecraft of the giant asteroid Vesta in front of a background of stars. It was obtained by Dawn's framing camera on May 3, 2011, from a distance of about 750,000 miles (1.2 million kilometers). CREDIT: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Crater patterns on Vesta and Ceres could help pinpoint when Jupiter began to form during the evolution of the early Solar System. A study modelling the cratering history of the largest two objects in the asteroid belt, which are believed to be among the oldest in the Solar System, indicates that the type and distribution of craters would show marked changes at different stages of Jupiter’s development. Results will be presented by Dr Diego Turrini at the European Planetary Science Congress in Potsdam, Germany, on Monday 14 September. The study, carried out by scientists at the Italian National Institute for...