Space junk - thousands of debris objects are hurtling around the earth with the potential of crashing into one another. As we launch more satellites, the risk of a satellite colliding with another satellite or a piece of space junk increases, threatening those satellite services we depend on. John Henderson, remote sensing scientist at Lawrence Livermore National Laboratory reviews the many ways we use satellites, how space collisions happen, how much of a danger space collisions are, and what can be done to prevent space collisions. (#24517)