The U.S. Air Force has successfully ground tested a Hard Target Smart Fuze (HTSF). The new fuze can detect when it has passed through hard material and entered an empty space, and do this for as many times as it is programmed to before detonating. The purpose of the HTSF is to destroy material in a multilevel bunker. If it is known that material to be destroyed is in a certain level of an underground bunker, the HTSF can be set to explode the bomb at that level, after simply penetrating the other levels. The fuze will be flight tested starting in April and enter production next January.