Alliant Techsystems (ATK) is under contract to develop the new Hard-Target Void-Sensing Fuze and plans to begin demonstrations in fiscal 2013. Production is slated to start in the middle of fiscal 2014.
A void-sensing fuze is the “Holy Grail” of fuzing, says Merchant. “Fuzes and hard targets don't work well together,” largely because of the lateral and vertical loads placed on a weapon penetrating concrete at high speed.
The service has manufactured developmental versions of the Massive Ordnance Penetrator (MOP). At 30,000 lb. and carrying 5,000 lb. of explosive fill, MOP is the largest conventional munition in the U.S. arsenal, and it is ready for use on the B-52 and B-2 bombers. But MOP currently lacks a void-sensing capability.
Because of MOP, however, improved processes have been devised for pinning internal equipment onto the electronics boards so that they stay intact through a violent penetration, says Merchant. He also notes that the Air Force was able to incorporate more “observing features” into the MOP design, meaning that the weapon can provide more data to commanders about how it executed its mission, potentially giving key details for a bomb-damage assessment. Self-assessing capabilities are another feature sought for future weapons, says Hinote.
In the meantime, the Air Force will begin incorporating electronic safe and arming devices on its fuzes. These will lack the less reliable mechanical parts of their predecessors. Merchant says funding available, and the Air Force will phase this capability into the FMU-152A/B Joint Programmable Fuze, which has already demonstrated a reliability of more than 98%, as these devices replace the FMU-139s in service. Merchant says that with a $50-75 million investment, the new electronic safe and arm capability can be qualified within two years.
Overall, however, the fuze industrial base continues to be fragile, owing to the exacting nature of the work and notoriously low financial return. Manufacturers such as L-3 Communications, ATK and Kaman receive far more orders for electronics for commercial items such as mobile phones. Thus, the Pentagon has a hard time keeping up with the current generation of electronics in production owing to a lag in qualifying them for weapons use. And it is not financially viable for manufacturers to continue building older Pentagon designs without certainty regarding projected orders.
Merchant says he is pushing in the forthcoming fiscal 2014 budget request to “refill the bucket” of funding. Fuze reliability will become even more crucial as the F-35 is introduced into service. With 2-8 weapons carried internally for stealthy use, the drawback to encountering a dud on a mission is even worse than with today's fighters that have a larger loadout.
The portfolio of existing weapons is largely healthy, Merchant says. It includes the once-troubled Lockheed Martin Joint-Air-to-Surface Standoff Missile, or Jassm (a stealthy cruise missile), Boeing's 250-lb. Small-Diameter Bomb and various Joint Direct Attack Munition (JDAM) kits, as well as the Raytheon AIM-9X short-range, air-to-air missile. Jassm, which is now being fielded, is expected to have a 15-year service life. JDAM and SDB are expected to be in service at least 20 years. The BRU-61 bomb rack is designed to carry four SDBs in each JDAM position on the F-22, quadrupling the number of ground targets it will eventually be able to attack in a single sortie.
In contrast, Raytheon's AIM-120D Amraam has suffered setbacks. Despite years of development and $2 billion spent to incorporate improved kinematic software, a new data link and better electronic-protection capabilities to the internationally available AIM-120C7, the U.S.-only D continues to slip further behind schedule.
The current problem is faulty rocket motors provided by ATK, prompting the Air Force to halt motor production and to withhold $621 million in payments to Raytheon pending delivery of all-up rounds. At issue was firing the motor at the extreme edge of its design parameters, about 165 deg., said Harry Schulte, Raytheon's vice president of air warfare systems, who spoke with Aviation Week at the Farnborough air show this summer.