A method of retrieving a mobile platform from a tank at least partially filled with a non-conductive, energetic substance (12, 14), the method characterized by: - configuring the mobile platform to include at least: - an enclosure, - at least one control unit positioned inside the enclosure, - at least one propulsion system positioned at least partially inside the enclosure, - at least one power supply positioned inside the enclosure, - at least one retrieval system disposed at least partially on the enclosure, the at least one retrieval system including at least one buoyant body, an electrically conductive member, and at least one tether, the at least one tether having at least a portion that is not conductive, the at least one tether electrically isolating the at least one buoyant body from the enclosure; - lowering the mobile platform into the tank using a deployment carrier (50, 764, 780); - submerging the enclosure in a non-conductive, liquid energetic substance; - moving the mobile platform using the at least one propulsion system to perform at least one task in the tank; - releasing the buoyant body to convey the at least one tether toward a surface of the non-conductive, liquid energetic substance; - conveying an electrically conductive cable to the electrically conductive member of the mobile platform using the at least one tether; - electrically connecting a voltage neutralizing end of the electrically conductive cable to a voltage differential neutralizing body in a spark inhibiting ambient condition; - electrically connecting a mobile platform end of the electrically conductive cable to the electrically conductive member of the mobile platform while the electrically conductive member is below the surface of the non-conductive, liquid energetic substance; and - retrieving the mobile platform from inside to outside of the tank. - configuring the mobile platform to include at least: - an enclosure, - at least one control unit positioned inside the enclosure, - at least one propulsion system positioned at least partially inside the enclosure, - at least one power supply positioned inside the enclosure, - at least one retrieval system disposed at least partially on the enclosure, the at least one retrieval system including at least one buoyant body, an electrically conductive member, and at least one tether, the at least one tether having at least a portion that is not conductive, the at least one tether electrically isolating the at least one buoyant body from the enclosure; - an enclosure, - at least one control unit positioned inside the enclosure, - at least one propulsion system positioned at least partially inside the enclosure, - at least one power supply positioned inside the enclosure, - at least one retrieval system disposed at least partially on the enclosure, the at least one retrieval system including at least one buoyant body, an electrically conductive member, and at least one tether, the at least one tether having at least a portion that is not conductive, the at least one tether electrically isolating the at least one buoyant body from the enclosure; - lowering the mobile platform into the tank using a deployment carrier (50, 764, 780); - submerging the enclosure in a non-conductive, liquid energetic substance; - moving the mobile platform using the at least one propulsion system to perform at least one task in the tank; - releasing the buoyant body to convey the at least one tether toward a surface of the non-conductive, liquid energetic substance; - conveying an electrically conductive cable to the electrically conductive member of the mobile platform using the at least one tether; - electrically connecting a voltage neutralizing end of the electrically conductive cable to a voltage differential neutralizing body in a spark inhibiting ambient condition; - electrically connecting a mobile platform end of the electrically conductive cable to the electrically conductive member of the mobile platform while the electrically conductive member is below the surface of the non-conductive, liquid energetic substance; and - retrieving the mobile platform from inside to outside of the tank.