Abstract: Improved ice penetrator apparatus includes protective apparatus for the thermochemical ice penetrator to prevent an undesired explosive sound producing chemical reaction between water and the material of said ice penetrator, particularly while the penetrator is resident in a buoy tube prior to release. The protective apparatus at least partially covers the thermochemical ice penetrator and forms a unitary assembly therewith. The characteristic of the protective material is such that it is non-reactive to the ice penetrator material, typically lithium and/or a sodium lithium alloy, and to water. The protective apparatus may assume any of a diving bell, clam shell and banana skin structural form.