Next month, the U.S. Navy will test fire Tomahawk missiles from an Ohio class ballistic missile submarine (SSBN). This has never been done before, but the test is being done to check out the new Tomahawk All-Up-Round (AUR) missile launching system. The navy wants to convert older Ohio subs to carry AURs (each containing seven Tomahawk missiles), in 22 of their 24 missile silos, instead of ballistic missiles.