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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.

RIO DE JANEIRO, March 25 (Xinhua) -- The number of dengue fever cases in Rio de Janeiro city this year has already surpassed 10,000, local health authorities said on Friday.According to the city's Health Secretariat, in less than three months, the number of confirmed dengue fever cases in Rio reached 10,158, exceeding the figures registered in the entire years of 2009 (2,723) and 2010 (3,120).In Rio de Janeiro state, the number of confirmed dengue fever cases reached 20,150, and the death toll rose to 18.This week, the first two cases of type-4 dengue fever in Rio de Janeiro state were confirmed in the city of Niteroi. The type-4 dengue fever is not more dangerous than the other types, but as the disease had not been registered in the region before, the local population has no immunity to it.As there are four different types of dengue fever, a person can develop the disease several times.The last epidemic of dengue fever in Rio de Janeiro state occurred in 2008 when 174 people died of the disease and some 250,000 cases of dengue were registered.

TAIPEI, Jan. 23 (Xinhua) -- Five crewmen, including four Chinese mainlanders, had been rescued after their fishing boat from Taiwan's Keelung capsized Friday night off southern Taiwan's Kenting, local sources said Sunday.The other two crewmen, including the Taiwanese captain and one mainland fisherman, were still missing. The rescue efforts were still under way.The fishing boat was ravaged by strong winds and huge waves Friday night.

WASHINGTON, March 9 (Xinhua) -- U.S. space shuttle Discovery landed safely at the Kennedy Space Center in Florida on Wednesday, ending its nearly 27-year flying career as the world's most- traveled spaceship.According to NASA, Discovery touched down at 11:57 a.m. EST ( 1657 GMT) after a 13-day resupply mission to the International Space Station (ISS)."For the final time: wheels stop," Discovery's commander Steven Lindsey called out as the shuttle rolled to a full stop.Discovery lifted off on Feb. 24 from the Kennedy Center and arrived at the space station on Feb. 26.During the mission, the astronauts installed a spare closet module on the space station, completed some important repairs and delivered the first humanoid robot, though it will need more time to be assembled and made operational.The 330-pound R2 consists of a head and a torso with two arms and two hands. Once it is unpacked -- likely several months after its arrival at the station -- it will initially be operated inside the Destiny laboratory for operational testing, but over time both its territory and its applications could expand.Aboard the station, its primary job for now is teaching engineers how dexterous robots behave in space. However, the hope is that through upgrades and advancements, it could one day venture outside the station to help spacewalkers make repairs or additions to the station or perform scientific work.

CHICAGO, Jan. 21 (Xinhua) -- Chinese President Hu Jintao left Chicago for China on Friday after concluding a state visit to the United States, during which he and his U.S. counterpart Barack Obama agreed to build a China-U.S. cooperative partnership based on mutual respect and mutual benefit.Hu, who began his four-day visit Tuesday, had extensive and in-depth discussions with Obama at the White House on Wednesday on major bilateral, regional and world issues.Chinese President Hu Jintao shakes hands with U.S. President Barack Obama during a bilateral meeting at the White House in Washington, the United States, Jan. 19, 2011.The two sides reached "important agreement on China-U.S. relations and major international and regional issues of shared interests," the Chinese president said when he and Obama met the press following their discussions."We both agree to further push forward the positive, cooperative and comprehensive China-U.S. relationship," Hu said, adding that both sides also pledged to forge "a China-U.S. cooperative partnership based on mutual respect and mutual benefit" for the benefit of the two countries and beyond.