Space may be big, but say if the Plutonian system has more than just moons knocking around?
"Even more worrisome than the possibility of many small moons themselves is the concern that these moons will generate debris rings, or even 3-D debris clouds around Pluto that could pose an impact hazard to New Horizons as it flies through the system at high speed," he adds.
Imagine driving down a freeway at 70 miles per hour only to hit a lane filled with nails - you'd be lucky to walk away from your car with just a blow-out. Now imagine driving straight into a cloud of nails. That probably wouldn't end so well.
Now, if you scale the situation up to spacecraft speeds, a serious problem presents itself. According to Stern: "...at our 14-kilometer-per-second (31,300 miles per hour) flyby speed, even particles less than a milligram can penetrate our micrometeoroid blankets and do a lot of damage to electronics, fuel lines and sensors."
In light of the very real risk of the high-speed New Horizons getting punctured by an errant piece of rocky debris - or slamming into the surface of a much larger object (a mile-wide previously unnoticed moon, say) - the New Horizons team hosted a workshop on Nov. 3-4 at the Southwest Research Institute's offices in Boulder, Colo. 20 experts in ring systems, orbital dynamics and astronomical observing techniques gathered to put together a plan of action ahead of the flyby in three years time.