Private space exploration company SpaceX has conducted its first successful launch since the explosion of a rocket on the launchpad in September. SpaceX sent the rocket into space Saturday from Vandenberg Air Force Base, California, and landed the first-stage mechanism successfully on a barge in the Pacific Ocean, an important step in development of reusable rocket components. The company hopes to reduce the cost of future space travel by developing a dependable system of retrieving and reusing launch rockets for future missions. The Falcon 9 rocket lifted off at 9:54 a.m. PST, carrying 10 communications satellites to be placed in orbit before returning to Earth. The first-stage piece of the rocket landed on the ocean barge about eight minutes after liftoff. Last year, a Falcon 9 exploded on a Florida launchpad during a preflight test. Investigators determined that a helium tank had burst inside a liquid oxygen tank, triggering the explosion. The rocket launched Saturday included modifications made in response to that accident, including a redesigned helium canister. SpaceX also has adjusted its fueling procedures to minimize danger. SpaceX is a private company that is expected to begin transporting U.S. astronauts into space next year. It also plans next year to launch a spacecraft headed to Mars. The company has a backlog of some 70 missions worth a total of $10 billion.