“…Higher velocities can be ARTICLE IN PRESS achieved with single stage guns using solid propellants, but this has the disadvantage of producing a great deal of residue which has to be cleaned out each time the gun is fired. To achieve impact speeds typical, say, of the impact of space debris on an orbiting satellite requires two-or even three-stage guns [154,155]. One disadvantage is that each successive stage is of smaller diameter than the one before.…”