The Tier III Minus UAV, known by the nickname DarkStar, was one of two high altitude endurance UAVs being developed for the Defense Airborne Reconnaissance Office (DARO) by the Advanced Research Projects Agency (ARPA) joint UAV program office. The Department of Defense canceled the Dark Star UAV program in February 1999 due to budget cuts. Given a trade-off between stealth and range, the Air Force chose the range of Global Hawk over Darkstar's stealth.
The Tier III Minus program is the first project to be executed under the "Section 845 Authority" granted to ARPA for prototype weapons development projects. This authority has paved the way for unprecedented government-industry collaboration by removing the burden of specialized Defense procurement regulations and statutes. The Tier Three Dark Star came with a one page specification that simply specified best altitude, endurance, and signature for a $10M (94$) unit cost for units 11-20.
At a planned $10 million a copy (FY94 dollars), the DarkStar UAV was intended to provide affordable, near real time, continuous, all weather, wide area surveillance in support of tactical commanders. The result would be timely information that the tactical commander can immediately exploit for accurate situational awareness and to perform precision strikes and other high priority intelligence and reconnaissance tasks.
The DarkStar system is a high-altitude, endurance unmanned air vehicle optimized for reconnaissance in highly defended areas. Physically, it is a little over half the span and a third the length of the Global Hawk aircraft. The Common Ground Segment, being developed by Raytheon/E-Systems, combines mission planning, command and control, communications and imagery quality control for both systems into a transportable system housed in two ruggedized shelters. Optimized for low observables, DarkStar's operational goal is to be highly survivable while penetrating high threat environments. Complementing the Tier III Minus is the Tier II Plus, which will be optimized for long range and endurance in a low-to-moderate threat environment. Both vehicles will be capable of fully autonomous take-off, flight and recovery; be capable of dynamic retasking while in flight.
It will operate within the current military force structure, and with existing command, control, communications, computer and intelligence equipment. It can operate at a range of 500 nautical miles from the launch site and will be able to loiter over the target area longer that eight hours at an altitude of more than 45,000 feet, carrying either an electro-optical or synthetic aperture radar sensor payload.
The DarkStar offers a 1,000-pound payload and carries either a low probability of intercept (LPI) SAR or EO sensor, one at a time, and offers similar collection rates and imagery resolution, though its capacity per mission is less due to its reduced endurance. Northrop Grumman Electric Sensors and Systems is developing the DarkStar SAR and Recon [reconnaissance] Optical is developing the EO sensor. The common ground station will disseminate the imagery product from the two air vehicles to existing exploitation systems.
The sensor system is similar to the Global Hawk, except there is less bandwidth in terms of the communications links because of the low observable installation of the antennas. In addition DarkStar carries either the radar or the EO payload on this aircraft, whereas Global Hawk can carry both payloads simultaneously. The radar payload has the same capability as the Global Hawk radar, with the exception of not having a GMTI mode. The EO system is a little bit degraded in terms of the NIIRS it can provide, but per hour it provides the same level of area coverage capability or the same number of spots per hour as provided with the Global Hawk system.
When Dark Star missions are allocated to Army commanders, or an Army officer is the JTF commander, the Enhanced Tactical Radar Correlator (ETRAC) and Modernized Imagery Exploitation System (MIES) (or successor processors) will process the imagery. If the U.S. Air Force is the "lead" Service, the processor would be the Contingency Airborne Reconnaissance System (CARS); if the Navy and Marines go in first, the Joint Services Imagery Processing System-Navy (JSIPS-N) would process the imagery. The Common Ground Station (CGS) will display the imagery no matter which system processed it.
A Lockheed/Boeing team is leading the development of the Tier III Minus (DarkStar) system. Each company is responsible for approximately 50 percent of the development program. Boeing Military Aircraft Division, Seattle, WA is responsible for the wing and wing subsystem development and testing, and Lockheed Martin Skunk Works, Palmdale, CA is responsible for the design and development of the body and its subsystems, final assembly, integration and system test. A single turbo-fan engine, supplied by Williams International, provides power for the vehicle.
The planned first flight of DarkStar occurred in March 1996; however, a second flight in April 1996 crashed due to incorrect aerodynamic modeling of the vehicles flight control laws. On 22 December 1996 Undersecretary of Defense for Acquisition and Technology Paul G. Kaminski approved the revised DarkStar High Altitude Endurance Unmanned Aerial Vehicle program plan. The revised program plan is a result of an independent review of the program following the crash of the first DarkStar air vehicle in April 1996. The review was conducted by an independent group of leading experts from government, industry and academia, and provided a detailed assessment of the entire DarkStar system and the program's processes and procedures. The review concluded that: (1) the contractor team understands the cause of the accident, (2) the DarkStar simulation now matches the data from the first and second test flights, and (3) the processes and procedures used in software development and test and system test have been significantly improved.