Shuttle steers closer to space station for hookup

Space shuttle Discovery's astronauts steered closer to the international space station for a Sunday linkup, while checking their ship for any signs of launch damage. The routine survey began early Saturday evening and lasted until the wee hours of Sunday. NASA officials say no fuel tank debris was observed hitting Discovery during Friday's midnight liftoff. But the shuttle's most vulnerable areas — the wings and nose — still needed to be inspected with lasers and cameras on a boom attached to the robot arm. The images were beamed down for analysis. Some of the images got held up because of a digital TV feed problem, but the early indication was that the survey results looked good. In addition, the shuttle's underside will be photographed in detail by the space station residents Sunday night, right before the two craft meet. Discovery is loaded with supplies for the space station, now home to six astronauts.

Source by Dunya News

US shuttle Discovery docks with space station

The US shuttle Discovery made a textbook docking late Sunday with the International Space Station (ISS). Nasa launched the US shuttle Discovery for a mission to the with seven astronauts on board. It lifted off from the Kennedy Space Center in Florida at 2359 EDT Friday (0359GMT Saturday). Two previous attempts to launch the orbiter had been postponed by a mix of bad weather and a technical glitch affecting its main propulsion system. Discovery's mission will be the 30th flight dedicated to ISS maintenance. Science equipment and a freezer to store research samples are among the items on board. It also carries a new sleeping compartment, an air purification system and a treadmill to help maintain astronauts' health.

Source by Dunya News

Wind Power

Wind is the movement of air from an area of high pressure to an area of low pressure. In fact, wind exists because the sun unevenly heats the surface of the Earth. As hot air rises, cooler air moves in to fill the void. As long as the sun shines, the wind will blow. And as long as the wind blows, people will harness it to power their lives.
Ancient mariners used sails to capture the wind and explore the world. Farmers once used windmills to grind their grains and pump water. Today, more and more people are using wind turbines to wring electricity from the breeze. Over the past decade, wind turbine use has increased at more than 25 percent a year. Still, it only provides a small fraction of the world's energy.
Most wind energy comes from turbines that can be as tall as a 20-story building and have three 200-foot-long (60-meter-long) blades. These contraptions look like giant airplane propellers on a stick. The wind spins the blades, which turn a shaft connected to a generator that produces electricity. Other turbines work the same way, but the turbine is on a vertical axis and the blades look like a giant egg beater.
The biggest wind turbines generate enough electricity to supply about 600 U.S. homes. Wind farms have tens and sometimes hundreds of these turbines lined up together in particularly windy spots, like along a ridge. Smaller turbines erected in a backyard can produce enough electricity for a single home or small business.
Wind is a clean source of renewable energy that produces no air or water pollution. And since the wind is free, operational costs are nearly zero once a turbine is erected. Mass production and technology advances are making turbines cheaper, and many governments offer tax incentives to spur wind-energy development.
Some people think wind turbines are ugly and complain about the noise the machines make. The slowly rotating blades can also kill birds and bats, but not nearly as many as cars, power lines, and high-rise buildings do. The wind is also variable: If it's not blowing, there's no electricity generated.
Nevertheless, the wind energy industry is booming. Globally, generation more than quadrupled between 2000 and 2006. At the end of last year, global capacity was more than 70,000 megawatts. In the energy-hungry United States, a single megawatt is enough electricity to power about 250 homes. Germany has the most installed wind energy capacity, followed by Spain, the United States, India, and Denmark. Development is also fast growing in France and China.
Industry experts predict that if this pace of growth continues, by 2050 the answer to one third of the world's electricity needs will be found blowing in the wind.