This month marks the 45th anniversary of Pioneer 10’s passage through the asteroid belt. It was a key rite of passage in humanity’s journey from this blue planet into the deep reaches of outer space. Unlike the crowded swarms of science-fiction movies, the real asteroid belt is overwhelmingly empty space. Still, nobody knew exactly what to expect. Would Pioneer 10 be pelted with dust-speck micrometeoroids? Was the asteroid belt a serious barrier to exploration?

As it turned out, the dust