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WASHINGTON, May 11 (Xinhua) -- NASA's Dawn spacecraft has obtained its first image of the giant asteroid Vesta, which will help fine-tune navigation during its approach, the U.S. space agency announced Wednesday.Dawn expects to achieve orbit around Vesta on July 16, when the asteroid is about 117 million miles from Earth.The image from Dawn's framing cameras was taken on May 3 when the spacecraft began its approach and was approximately 752,000 miles (1.21 million km) from Vesta. The asteroid appears as a small, bright pearl against a background of stars. Vesta also is known as a protoplanet, because it is a large body that almost formed into a planet."After plying the seas of space for more than a billion miles, the Dawn team finally spotted its target," said Carol Raymond, Dawn's deputy principal investigator at NASA's Jet Propulsion Laboratory in Pasadena, California. "This first image hints of detailed portraits to come from Dawn's upcoming visit."Vesta is 330 miles (530 km) in diameter and the second most massive object in the asteroid belt. Ground- and space-based telescopes obtained images of the bright orb for about two centuries, but with little surface detail.Mission managers expect Vesta's gravity to capture Dawn in orbit on July 16. To enter orbit, Dawn must match the asteroid's path around the sun, which requires very precise knowledge of the body's location and speed. By analyzing where Vesta appears relative to stars in framing camera images, navigators will pin down its location and enable engineers to refine the spacecraft's trajectory.Dawn will start collecting science data in early August at an altitude of approximately 1,700 miles (2,700 km) above the asteroid's surface. As the spacecraft gets closer, it will snap multi-angle images allowing scientists to produce topographic maps. Dawn will later orbit at approximately 120 miles (200 km) to perform other measurements and obtain closer shots of parts of the surface. Dawn will remain in orbit around Vesta for one year. After another long cruise phase, Dawn will arrive in 2015 at its second destination, Ceres, an even more massive body in the asteroid belt.Gathering information about these two icons of the asteroid belt will help scientists unlock the secrets of our solar system's early history. The mission will compare and contrast the two giant asteroids shaped by different forces. Dawn's science instruments will measure surface composition, topography and texture. Dawn also will measure the tug of gravity from Vesta and Ceres to learn more about their internal structures. The spacecraft's full odyssey will take it on a 3-billion-mile (5-billion-km) journey, which began with its launch in September 2007.

SAN FRANCISCO, March 29 (Xinhua) -- Amazon.com Inc. on Tuesday announced the launch of an on-line music storage service,which enables users to store digital music in the cloud and access it from computers and devices running Google's Android operating system.The new service, called "Cloud Drive," offered customers five gigabytes of free storage on Amazon Web servers for all kinds of digital files, including music, photos, videos and documents. For paid plans, users can purchase storage space starting at 20 U.S. dollars a year for 20 gigabytes.The on-line retailer also launched "Cloud Player for Web" and " Cloud Player for Android." The former allows users to get the media files they stored on Amazon's servers from a Web browser on a Mac or PC. The latter lets users play music they have uploaded on Cloud Drive, computers or a smartphone that runs Android operating system.Analysts said Amazon is stepping up its rivalries with Apple and Google. Both companies are also working on similar services, allowing users to store their music on-line and access it from any compatible device.Media reports said that Apple was pushing hard to launch a digital music locker service in April. Google was also reported to be testing its own digital locker service but it still needs to make agreements with major music labels.

SAN FRANCISCO, April 7 (Xinhua) -- A latest research has shown that worldwide camera phone sales, driven by fast growing high- tier camera phone market, will top 1 billion units for the first time in 2011.According to the study by Strategy Analytics, a global independent research and consulting firm, sales of camera phones are projected to grow by 21 percent from 918 million units last year to 1.114 billion units in 2011, which will be the first time that annual volumes of camera phones have exceeded the 1-billion mark."The fastest growing segment of the camera phone market will be the high-tier. We forecast camera phones with sensors of eight megapixels and above to grow a healthy 240 percent worldwide during 2011," Neil Mawston, director at Strategy Analytics, said in a statement on Thursday.He added that smartphone vendors, such as Nokia and HTC, are increasingly loading their flagship models with more megapixels to deliver improved imaging quality for premium operator services.Statistics from Strategy Analytics show that some 4.2 billion camera phones have been sold worldwide since 2000.

来源：资阳报