Science / Medicine : 25th Birthday for Pioneer 6

The oldest spacecraft still in operation, designed to last for six months, turned 25 Sunday and is still sending back scientific data.

Pioneer 6, the first spacecraft to pass behind the sun, has traveled more than 15.4 billion miles since it was launched in 1965. Since the 140-pound spacecraft cost only $6 million, the long journey has only cost about .04 of a cent per mile, according to officials with TRW Inc., of Redondo Beach, where the small craft was built.

Although Pioneer’s instruments are still capable of studying the sun, other missions have supplanted it to the point that it has been more than five months since the National Aeronautics and Space Administration checked in with the aging veteran. But today the spacecraft will be tracked again for about two hours to mark the anniversary.

In addition, the California Museum of Science and Industry in Exposition Park will display a full scale model of Pioneer 6 in the Aerospace Hall until Jan. 4.