IDF Artillery Corps, the M109 howitzer, will be phased out in favor of a still-undecided replacement, with the ATMOS 2000 and Artillery Gun Module under primary consideration. The IDF is also planning a future tank to replace the Merkava. The new tank will be able to fire lasers and electromagnetic pulses, run on a hybrid engine, run with a crew as small as two, will be faster, and will be better-protected, with emphasis on protection systems such as the Trophy over armor. The Combat Engineering Corps assimilated new technologies, mainly in tunnel detection and unmanned ground vehicles and military robots, such as remote-controlled IDF Caterpillar D9T "Panda" armored bulldozers, Sahar engineering scout robot and improved Remotec ANDROS robots. The Israeli Air Force will purchase as many as 100 F-35 Lightning II fighter jets from the United States. The aircraft will be modified and designated F-35I. They will use Israeli-built electronic warfare systems, outer-wings, guided bombs, and air-to-air missiles. As part of a 2013 arms deal, the IAF will purchase KC-135 Stratotanker aerial refueling aircraft and V-22 Osprey multi-mission aircraft from the United States, as well as advanced radars for warplanes and missiles designed to take out radars. In April 2013, an Israeli official stated that within 40–50 years, piloted aircraft would be phased out of service by unmanned aerial vehicles capable of executing nearly any operation that can be performed by piloted combat aircraft. Israel's military industries are reportedly on the path to developing such technology in a few decades. Israel will also manufacture tactical satellites for military use. The Israeli Navy is currently expanding its submarine fleet, with a planned total of six Dolphin class submarines. Currently, five have been delivered, with the sixth, INS Drakon, expected to be delivered in 2020. It is also upgrading and expanding its surface fleet. It is planning to upgrade the electronic warfare systems of its Sa'ar 5-class corvettes and Sa'ar 4.5 class missile boats, and has ordered two new classes of warship: the Sa'ar 6-class corvette (a variant of the Braunschweig-class corvette) and the Sa'ar 72-class corvette (an improved and enlarged version of the Sa'ar 4.5-class). It plans to acquire four Saar 6-class corvettes and three Sa'ar 72-class corvettes. Israel is also developing marine artillery, including a gun capable of firing satellite-guided 155mm rounds between 75 and 120 kilometers. See also Security forces Intelligence Community Shabak Mossad National Security Council Israeli police