For 19 years, space scientists, astronomers and physicists have been trying to find an explaination for a mysterious force that seems to be pulling spacecraft in the direction of the Sun. A team of investigators has now announced that, after examining and ruling out most of the possibilities they could think of, the mystery remains unsolved. This means, they said in a report accepted for publication in the journal Physical Review Letters, that there is a possibility some hitherto unknown phenomenon might be at work. Heading the group of six scientists who studied the anomalous attraction mystery was John Anderson, an astronomer at the Jet Propulsion Laboratory in Pasadena, California.