Earth’s orbit is filled with debris which often collides with other debris to create — you guessed it — even more debris. The problem with all this space junk is that it forms belts that are off-limits to new satellites. So how do we clean up our orbit? Daniel Gregory of Raytheon BBN Technologies is working on a way to fire focused pulses of atmospheric gases directly into the path of debris. That would create enough drag to slow the material down until it drops out of orbit and burns away harmlessly in our atmosphere.