Lockheed Martin-Boeing RQ-3A DarkStar
In the early 1990s, the USAF decided to integrate various Intelligence, Surveillance and Reconnaissance (ISR) systems to ensure that all US Forces would be provided with the appropriate information necessary to successfully conduct military operations. As part of this integration, the Defence Airborne Reconnaissance Office (DARO) issued a requirement for long endurance UAVs with reconnaissance, surveillance and target acquisition capabilities. This in turn led to the Defence Advanced Research Projects Agency (DARPA) overseeing development of a pair of complementary High Altitude Endurance (HAE) UAVs, under their policy of producing Advanced Concept Technology Demonstration (ACTD) versions of each design and then ensuring they perform as advertised. The two designs were the RQ-3A Darkstar, developed by Lockheed Martin & Boeing and the RQ-4A Global Hawk developed by Northrop Grumman – two different designs to meet specific mission criteria. Northrop Grumman’s relatively conventional UAV design enabled the Global Hawk to provide long range & endurance and carry a multi-sensor payload in a low –to-moderate threat environment.
However, Lockheed Martin developed a low-observable design, incorporating a considerable amount of stealth technology, enabling the UAV to operate in highly defended areas. The Lockheed Martin Skunk Works were responsible for building the fuselage and integrating the ReconOptical Electro-Optical (EO) sensor and various other sub-systems. Boeing were responsible for building the wings and avionics, as well as integrating the Westinghouse Synthetic Aperture Radar (SAR), a legacy from the US Navy’s cancelled A-12 programme, as well as the vehicle management system.
The DarkStar was designed to carry either the interchangeable SAR or EO sensor at altitudes above 45,000ft and 250kts, operating up to 500nms from its base for around 8 hrs and was powered by a single Williams-Rolls FJ44-1A turbofan engine – the same engine used in the Cessna Citation business jet. The digital SAR and EO systems enabled images to be transmitted in near real-time to a ground station or satellite. Designed to be fully autonomous and follow a programmed sortie, DarkStar could take off, fly to its assigned target area, transmit its sensor imagery, return to base and land without any human intervention. Nevertheless, if DarkStar was within line-of-sight of its ground station, it could be re-programmed in flight to alter course and direct its sensors at another target; beyond line-of-sight the ground station could remain in touch via a satellite link.
DarkStar first flew from Edwards AFB on 29 Mar 96, but then on its second flight on 22 Apr 96, due to a software fault in the flight control system, the vehicle developed uncontrollable oscillations after take-off, stalled nose high and crashed.. A second DarkStar first flew on 29 Jun 98 and during testing on 11 Jan 99 reached an altitude of 25,000ft on a 2hr 37 min sortie. The third and fourth DarkStar vehicles were completed when, because of budget cutbacks, the DoD cancelled the DarkStar programme in late Jan 99. The thinking behind the decision has never been explained, however, it was probably becoming apparent that the Global Hawk could meet every requirement for both programmes, apart from the need for stealth. Also, as Global Hawk would probably only ever operate within airspace in which the USAF had already gained air superiority, the requirement for low-observable technology was minimal.
To date, the DarkStar is probably the stealthiest UAV to have publicly flown, given the profile of the vehicle, the radar cross-section would have been extremely small and would have enabled the DarkStar to operate with virtual impunity in the most hostile airspace, whilst sending back crystal-clear images to its ground station. However, DARPA realised the value of such a UAV and have developed and flown other stealthy UAVs as well as instigating a concept programme to develop a revolutionary UAV named SensorCraft. The only surviving DarkStar to have flown is now preserved in the USAF Museum.
However, the original project definition in 1993, that eventually led to the Darkstar, called for a much larger, ultralong range. stealthy UAV, similar in size to the Northrop B-2 bomber. Lockheed Martin's design was named the Quartz, but this was offically cancelled when the Cold War ended, despite over $1 billion having been spent on this programme. Nevertheless, although the stealthy Darkstar UAV was officially cancelled back in Feb 99, there have been persistent reports that, as part of a ‘black’ programme, a larger derivative of this UAV was developed by Lockheed Martin and has been used in operations over Iraq. These rumours have been given added strength by the apparent inability of current UAVs to meet a long-standing USAF requirement for a very low observable, high-altitude UAV that can fly 1,000nm to a target area, penetrate a modern air defence system, loiter for at least 8hr and then return to base.
Although the first Darkstar crashed during a test flight on 22 Apr 96, the second Darkstar was modified and later flew successfully. Undoubtedly, some problems had been encountered during the development programme with the flight control system, the command & control system and the stealthy apertures, but these could almost have been expected during the development cycle of such an advanced UAV and were effectively cured. So if these problems had been overcome it seems odd for the programme to be have been cancelled, when the requirement remained extant and these doubts have fed persistent rumours of a follow-on black programme.
Little if anything has been said by Lockheed Martin about the new ‘Super Darkstar’ or Quartz or whatever name it has been given, other than the tacit admission recently by some well placed individuals from Lockheed Martin that the vehicle exists and has been used successfully in operations. They also confirmed that, whilst it cannot carry the same payload as a U-2S, it nevertheless is capable of carrying an LPI synthetic aperture radar as well as infra-red and electro-optical sensors. A number of U-2S pilots reported seeing an unknown high-flying vehicle, operating at or above the height of their own aircraft, whilst flying over Iraq. Lockheed Martin will probably attempt to keep this new UAV out of the limelight for as long as possible. Presumably the USAF have been willing to pay considerably more for this vehicle, compared to the non-stealthy Northrop Grumman Global Hawk, because of its capability to penetrate highly defended airspace undetected and the quality of intelligence it provided.
Updated October 2006