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WASHINGTON, July 7 (Xinhua) -- Space shuttle Atlantis will soar into the sky Friday on NASA's 135th and final flight. Its scheduled return to Earth later this month will mark the end of NASA's 30-year space program.Since its onset with the launch of space shuttle Columbia, the program has been seen as a cheap, safe and reliable way for space exploration.Despite its great contributions to U.S. manned space flight, it has also left some grave and tragic lessons, making its termination inevitable.HIKING COSTSLaunched in 1972 by then President Richard Nixon, the shuttle program aimed to provide a new system of affordable space travel and proved to be NASA's most enduring project in its 50 years of existence.In 1981, shuttle Columbia made its first shuttle flight for two days. It was the ultimate hybrid and the first reusable spacecraft.Launched like a rocket and gliding back to Earth like an airplane, space shuttles not only can act as a space taxi to carry astronauts, but have the muscle of a long-distance trucker to haul heavy machinery.The spaceship boasts more than 3,500 subsystems and 2.5 million parts and is nine times faster than a speeding bullet as it climbs heavenward. That versatility, however, has translated into higher costs.NASA originally estimated the program would cost about 90 billion U.S. dollars. However, its actual cost stands at about 200 billion dollars, compared with the 151 billion dollars spent on Apollo which took Americans to the moon in 1969.In an article in Technology Review, John Logsdon, former head of the Space Policy Institute at George Washington University, drew a direct connection between the ravenous shuttle budget and the lack of other large advances in manned space flight."By operating the system for 30 years, with its high costs and high risk, rather than replacing it with a less expensive, less risky second-generation system, NASA compounded the original mistake of developing the most ambitious version of the vehicle," he wrote."The shuttle's cost has been an obstacle to NASA starting other major projects," he added.HIGH RISKIn terms of safety, the shuttles have never been as reliable as their designers had envisioned.On average, one out of every 67 flights ended up with fatal accidents. Based on the rate of deaths per million miles traveled, the space shuttle is 138 times riskier than a passenger jet.Seven astronauts onboard died when Challenger exploded about a minute after launch in 1986. Nearly two decades after the tragic blast, a new catastrophe descended when the shuttle Columbia disintegrated moments before landing in 2003, killing another seven spacemen.Again, the shuttle program was shelved for more than two years as NASA stepped up efforts to make it safer. But experts say the fundamental problem related to shuttles' safety cannot be solved due to their "birth defects.""It is in the nation's interest to replace the Shuttle as soon as possible," concluded the panel that investigated the 2003 Columbia accident.

XIAMEN, July 23 (Xinhua) -- A rescue and breeding base for endangered Chinese white dolphins started a trial operational period on Saturday in the southeastern seaside resort of Xiamen. The base is the first of its kind in the country.The base, located on the city's Huoshaoyu Islet, includes a rescue center and a breeding area and can accommodate up to four to six white dolphins, said Pan Shijian, vice mayor of Xiamen.Previously, rescuers had to return injured white dolphins back to the sea after giving them simple medical treatment due to the lack of a rescue base, Pan said."From now on, the base will be a hospital for injured or stranded dolphins," he said.The base will also be used as a rehabilitation center for children with infantile autism and brain paralysis, with the dolphins acting as "doctors" during the children's recovery period, he added.The Chinese white dolphin mainly lives in the seas around Xiamen and the Pearl River estuary in south China. The dolphins are under first-class state protection.The Chinese Academy of Fishery Sciences estimates that about 2,000 of the dolphins are living in China's seas.

SAN FRANCISCO, Sept. 12 (Xinhua) -- Amazon.com Inc. is talking with book publishers to launch a rental subscription service for digital books, U.S. media reported on Monday.Several publishing executives said they aren't enthusiastic about the idea because it could lower the value of books and it could also strain their relationships with other retailers that sell their books, The Wall Street Journal quotes people familiar with the matter in a report.The Seattle-based company is considering a digital book library featuring old titles, which would be available to Amazon Prime subscribers, who currently pay 79 U.S. dollars a year for access to digital library of movies and TV shows and unlimited two-day shipping, said the report.Amazon would offer book publishers a substantial fee and could limit the amount of books that Amazon Prime customers could read for free every month, the report cited some sources as saying.The online retailing giant makes the popular electronic reader Kindle and is also reported to launch a color touchscreen tablet before October to compete with Apple's iPad and other devices in the increasingly crowded tablet computer market.The proposal is another sign that retailers are looking for more ways to deliver content digitally as customers increasingly read book and watch TV on personal computers, tablets and other electronic devices, said The Wall Street Journal report.

BEIJING, Aug. 13 (Xinhua) -- Chinese rating agency Dagong Global Credit Rating Co. on Saturday defended its AAA rating given to the Ministry of Railways, which has been under public fire over a train collision last month.The ministry received the long-term credit rating after launching on Monday its first bond sales since the crash on July 23 that killed 40 people near the Wenzhou city of eastern Zhejiang province.It sold 20 billion yuan worth of three-month bills on offer in the interbank market, with a yield of 5.55 percent, a relatively high rate for short-term government paper.The rating was assigned because of the ministry's status as a government agency backed by the central government revenue, its sufficient capital flows and strong financing ability, Dagong said in an email to Xinhua.The agency made the elaboration in response to market doubts as the ministry is already heavily indebted and the accident has stirred up skepticism about the its credibility and the safety of fast-expanding railways.Adding to doubts is that the AAA rating of the ministry is even a notch above China's local currency debt rating of AA+, which was also rated by Dagong.Government data showed the ministry's debts exceeded 2 trillion yuan (313 billion U.S. dollars) as of the end of June, raising its debt ratio to 58.53 percent, slightly up from the end of the first quarter of this year.Dagong said in the statement that the debt-to-asset ratio is medium level, lower than the alert line for the ministry which is 75 percent.The ministry has large-scale assets of good quality and relatively large room for fund-raising, Dagong said.The ministry has "extremely strong" repayment ability as it is backed by the state's credit, Dagong said, referring it as one of the three authorities that are allowed to issue bonds, along with the Ministry of Finance and the People's Bank of China.In July, the ministry issued 20 billion yuan of one-year commercial papers with a coupon rate of 5.18 percent, but only 18.73 billion yuan of the total was bought.Analysts said it has become more difficult for the ministry to borrow money because of tightened market liquidity and concerns over the ministry's debt burden.China's top four banks said at the end of last month that they will continue to offer loans to the ministry based on market conditions and risk appraisal. Credit from the four largest state-owned banks including the Industrial and Commercial Bank of China and the Construction Bank of China has been the major source funding the construction of China's fast-growing railways in recent years.

PARIS, June 14 (Xinhua) -- Solar Impulse, a Swiss solar-powered aircraft, finally arrived in Paris on Tuesday after three days' delay, ready for a debut at the biennial International Paris Air Show.The 1.6-ton solar-powered plane was expected to land in Paris on Saturday but technical problems and bad weather forced it to turn back to Brussels.The plane took its first international flight from Switzerland to Brussels on May 13 and then marked its second international flight to Paris. It has 12,000 solar cells mounted on the wings, which provide momentum for its four electric motors.Solar Impulse is the first aeroplane designed to fly day and night without requiring fuel and without producing carbon emission. The 64-meter-wingspan (as wide as an Airbus A340) can fly at extremely slow speed and has a weight equivalent to that of an average family car.Regarded as a "special guest" in the show, Solar Impulse made a historic 26-hour day and night flight without fuel in July 2010.During the Paris air show from 20 to 26 June, visitors can enjoy a close look at the innovative plane on ground every day and if weather condition permits, flying displays will take place.According to Paris Air Show organizers, 59 of the top 100 companies in the air industry worldwide will be present. More than 1,800 small and medium-sized companies will be exhibiting their products during the one-week show. Enditem

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