Nearly 3 billion miles from home, Pioneer 11 flew beyond the reaches of the solar system Friday, moving deeper into space to collect more information for scientists, the space agency said.

Pioneer 11, launched in 1973, became the fourth spacecraft to leave the confines of the solar system, joining Pioneer 10, Voyager 1 and Voyager 2.The National Aeronautics and Space Administration said Pioneer 11 crossed the orbit of Neptune about 2.8 billion miles from Earth. Neptune currently marks the outer limit of the solar system because the irregular orbit of Pluto, usually the most distant planet, carries it inside Neptune's path for the next 12 years.

Pioneer 11, which provided scientists with their closest view of Jupiter in 1974 and took the first close-up pictures of Saturn in 1979, probably will continue to return good data for about three years.