Science: Rocky Gauntlet in Space

As every sci-fi fan knows, one of the great hazards of space travel between the orbits of Mars and Jupiter is the asteroid belt: a doughnut-shaped stretch of floating debris that could fatally pierce the thin metallic skin of a speeding spacecraft. Now, for the first time, a real ship is beginning to run this rocky gauntlet. Success will increase the possibility of future missions to Jupiter and the other outer planets (Saturn, Uranus, Neptune and Pluto).

Launched from Cape Kennedy last March, the instrument-packed Pioneer 10 is scheduled to make the first flyby...