Last shuttle mission takes off

KENNEDY SPACE CENTER, Florida -- The space shuttle Atlantis lifted into orbit on Friday morning despite the threat of thunderstorms.

The four astronauts aboard are the last to ride the shuttle into space. NASA is retiring the 30-year-old program's reuseable spacecraft after this mission; the two other remaining shuttles -- Endeavour and Discovery -- have already been retired.

The shuttle shot into orbit, boosted with liquid and solid fuel rockets generating 7 million pounds of thrust. The astronauts are carrying scientific equipment and supplies to the International Space Station.

The United States will now rely on Russian Space Agency missions to carry astronauts to the International Space Station. NASA is working on its next generation of equipment to take men and women into space -- the Multi-Purpose Crew Vehicle, also known as Orion. The cone-shaped capsule will sit on the head of a rocket and can comfortably carry four astronauts and equipment. It is designed to be safe and, unlike the shuttle, cannot be guided back to Earth. It will splash down in the water like the earlier Apollo missions and as Russian missions now do.

Space shuttles were originally designed to be big space trucks, cheaply and efficiently carrying cargo and astronauts into space and then gliding back to Earth to be used over and over again. But costs quickly ballooned over early estimates, and the loss of two shuttles -- Columbia in 2003 and Challenger in 1986 -- made many Americans wonder if the vehicles were worth the risk.