Artist: Rick Guidice Pioneer 10 Crosses the Asteriod Belt: If spacecraft are to visit the outer Solar System, they must cross the asteroid belt between Mars and Jpiter. The Pioneer mission was faced with the question of just how dangerous this astroid belt would be to a spacecraft passing throught it. Note: used in NASA SP-349 'Pioneer Odyssey - Encounter with a Giant' fig. 1-24 and SP-446 ' Pioneer - First to Jupiter, Saturn, and Beyond' fig 1-24