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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.

BEIJING, August 4 (Xinhuanet) -- Medtronic Inc. is giving Yale University a 2.5 million U.S. dollar grant to review the safety and effectiveness of its controversial spine treatment called Infuse Bone Graft, according to The Wall Street Journals Thursday.Under terms of the pact, the company will release to Yale and eventually the public what participants described as an unprecedented amount of clinical trial and other data. The university will select two research teams from other organizations to perform separate analyses of the data.The announcement comes in the wake of a paper in June in the Spine Journal. The paper revealed that several clinical studies of Infuse, conducted by surgeons with strong economic ties to Medtronic, failed to report serious complications that arose in the trials. The critical paper also found that many of the studies were designed in ways in favor of Infuse over a treatment given to a control group.Medtronic disputes some of the findings and is conducting an internal investigation of the matter.Infuse accounts for about 700 million dollars in annual sales for Medtronic. The product is under investigation by the Senate Finance Committee over the role payments to physicians who may have played how studies were reported.

LOS ANGELES, June 9 (Xinhua) -- The edge of our solar system may not be smooth, but filled with a turbulent sea of magnetic bubbles approximately 100 million miles (160 million kilometers) wide, NASA's Jet Propulsion Laboratory (JPL) said on Thursday.The finding was based on observations from NASA's Voyager spacecraft, humanity's farthest deep space sentinels, said JPL in Pasadena, Los Angeles.While using a new computer model to analyze Voyager data, scientists found the sun's distant magnetic field is made up of bubbles which are created when magnetic field lines reorganize, said JPL.The new model suggests the field lines are broken up into self- contained structures disconnected from the solar magnetic field, according to JPL."The sun's magnetic field extends all the way to the edge of the solar system," said astronomer Merav Opher of Boston University. "Because the sun spins, its magnetic field becomes twisted and wrinkled, a bit like a ballerina's skirt. Far, far away from the sun, where the Voyagers are, the folds of the skirt bunch up."Like Earth, our sun has a magnetic field with a north pole and a south pole. The field lines are stretched outward by the solar wind, a stream of charged particles emanating from the star that interacts with material expelled from others in our corner of the Milky Way galaxy.Understanding the structure of the sun's magnetic field will allow scientists to explain how galactic cosmic rays enter our solar system and help define how the star interacts with the rest of the galaxy.The Voyager spacecraft, more than nine billion miles (14 billion kilometers) away from Earth, are traveling in a boundary region. In that area, the solar wind and magnetic field are affected by material expelled from other stars in our corner of the Milky Way galaxy.Launched in 1977, the Voyager twin spacecraft have been on a 33- year journey. They are en route to reach the edge of interstellar space. JPL built the spacecraft and continues to operate them.

SAN FRANCISCO, Sept. 6 (Xinhua)-- Yahoo on Tuesday fired Chief Executive Officer Carol Bartz and replaced her temporarily with the company's chief financial officer."On behalf of the entire board, I want to thank Carol for her service to Yahoo during a critical time of transition in the company's history, and against a very challenging macro-economic backdrop," said Yahoo Chairman Roy Bostock in a news release.The Yahoo Board of Directors appointed CFO Timothy Morse as interim CEO who will manage the company's day-to-day operations until a permanent chief executive is chosen.Carol Bartz, chief executive of Internet company Yahoo Inc, is shown in this undated publicity photo released to Reuters January 13, 2009. Before Yahoo's formal announcement, several news organizations and tech blogs posted an email reportedly from Bartz sent from her iPad to all employees of the company."To all, I am very sad to tell you that I've just been fired over the phone by Yahoo's Chairman of the Board. It has been my pleasure to work with all of you and I wish you only the best going forward."Bartz, 63, took over the Yahoo CEO role from co-founder Jerry Young in January 2009, when the company was struggling to stay competitive and profitable in a market dominated by Google. However, Yahoo never reached the heights she had foreseen.In the most recent quarterly earnings report in June, Yahoo reported net revenue of 1.1 billion U.S. dollars, down 5 percent from last year.Morse, 42, was hired as executive vice president and CFO at Yahoo in July 2009. "It is an honor to be selected for this role," he said in a statement Tuesday.Yahoo said it is starting a search for a new permanent CEO and plans to hire a "nationally recognized executive search firm" to assist in the effort.

BEIJING, June 10 (Xinhua) -- The nation's drug watchdog on Friday publicized a draft national standard of sulfur dioxide residue in Chinese herbal medicine, which is open for public opinion until Sept. 9 this year.The maximum amount of sulfur dioxide residue is 400 mg in one kg of each of 11 specified kinds of herbal medicine, such as Chinese yams, Gastrodia elata and Codonopsis pilosola, according to the draft standard unveiled by the State Food and Drug Administration (SFDA).The standard provides a 150-mg-per-kg limit for all other kinds of herbal medicine.Fumigation with sulfur is used as a way of drying some herbal medicine by growers, and currently have no alternative that is both cheap and convenient.The SFDA said it doesn't favor the drying herbal medicine through fumigation with sulfur and urges research efforts to invent new alternatives.According to the World Health Organization, the tolerable maximum amount of sulfur dioxide that a human body can take in one day is 0.7 mg per kg, which means that an adult of 60 kg should not take in more than 42 mg of sulfur dioxide a day.Long-term exposure to high amounts of sulfur dioxide can cause damage to human body, especially the respiratory system, according to experts.