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DARPA’s Vulture: What Goes Up, Needn’t Come Down

26-Aug-2008 12:30 EDT

Related Stories: Americas - USA, BAE, Britain/U.K., Contracts - Awards, DARPA, Design Innovations, Materials Innovations, New Systems Tech, Other Corporation, R&D - Contracted, Transformation, UAVs

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BQ Vulture concept
Boeing’s concept
(click to view full)

Three teams have now received Phase 1 contracts to begin developing develop a radical new aircraft, under a US Defense Advanced Research Projects Agency (DARPA) program known as “Vulture.”

DARPA’s goals for Vulture are not trivial: 5 years on station with a 450kg/ 1,000lb payload, 5kW of onboard power, and sufficient loiter speed to stay on station for 99% of the time against winds encountered at 60,000-90,000 feet. The system could act as a satellite substitute for communications relay or reconnaissance, as long as the payload fit within the weight limit. Vulture would be more vulnerable to anti-aircraft missiles than a satellite, and could be targeted by fighter jets as well given the right launch profile; on the other hand, that closeness would improve sensor resolution and communications capability.

The engineering challenges ahead are formidable, as one would expect for a DARPA project. The power system in particular must be extremely reliable, and the aircraft’s materials will require advances of their own. Odysseus will be exposed to far more warming and cooling than satellites, and more ultraviolet radiation which will affect the aircraft’s materials. The design is also likely to require very large wings, both to help keep it aloft and to accommodate the number of solar cells required. Conditions at altitude can challenge the durability of those wings, especially with hydrogen storage tanks attached. Aerovironment’s Helios (1998-2003) demonstrated this the hard way in its 2003 crash.

So, who is competing, and what are the proposed designs?

  • The Process, The Designers & The Designs
  • Contracts and Related Events [updated]
  • Additional Readings

The Process, The Designers & The Designs

Helios
AV’s Helios
(click to view full)

If Vulture reached its goals, it would become a very potent lower-cost competitor to the USA’s $20+ billion TSAT satellite program. DARPA projects aren’t like normal military system development projects, however, and have different goals. Several breakthroughs will be required for complete success, but even 1-2 breakthroughs in areas like materials durability at 60,000-90,000 feet will deliver advantages that can be carried over to other programs – such as the High Altitude Airship.

During Vulture’s Phase 1 conceptual system definition (12 months, 2008-2009), the firms will define their aircraft, run formal reliability and mission success analysis, and blueprint full-scale and subscale demonstrators. Phase 1 concludes with a System Requirements Review

The Phase 2 risk reduction development and testing phase (2009 – mid-2012) go-ahead would build and testing a subscale demonstrators capable of flying for 3 months, and would end with an uninterrupted 3-month system flight demonstration.

Phase 3 fabrication would involve a full-scale aircraft demonstrator capable of staying up for 12 months, a flight test for 12 uninterrupted months, and a program that reaches a Technology Readiness Level standard of TRL 6 overall. This would let Vulture enter System Design & Development as a program of record, if the military wished to field a design.

Odysseus, day
Odysseus, day
(click to view full)

DARPA contract winner Aurora Flight Science is involved in building Northrop Grumman’s high-altitude Global Hawk UAV, has worked on a “Mars Flyer”/ARES vehicle for NASA, and is also collaborating with Boeing and with General Dynamics on the hydrogen fuel cell powered, high altitude Orion HALL.

Aurora’s winning design in the above Flash movie [9 MB] is called “Odysseus,” using solar energy to power the aircraft during daylight, and stored solar energy to power the aircraft at night. Aurora’s Odysseus uses a “modular shuttling” approach, using 3 UAVs with 160 foot wingspans that can dock and separate in the air. This simplifies take-off and flight to altitude, while providing options if any of the 3 vehicles need to be recalled for maintenance or replaced. Solar power with fuel cells will keep Odysseus in the air, and the 3-vehicle design can go from a Z-shaped configuration to capture more of the day’s sunlight, to a straight wing configuration for low drag at night. See this 9 MB Flash movie for more.

Aurora’s teammates on the program include BAE Systems (payloads, sensors, and concept of operations and employment); C.S. Draper Laboratories (extremely high reliability electronics and control systems), and Sierra Nevada Corporation (specialist in autonomous refueling systems).

DARPA contract winner Boeing also has a varied team drawn from inside and outside the company. Boeing Integrated Defense Systems (IDS) Advanced Systems, IDS Space and Intelligence Systems, Boeing Spectrolab and Boeing Phantom Works are all involved. Their major partner is the British firm QinetiQ, whose solar-powered, carbon-fiber Zephyr high-altitude, long-endurance unmanned aerial system is currently flying under a joint Beitish-American program. Other partners include Versa Power Systems and C.S. Draper Laboratories.

Zephyr is a an ultra-lightweight carbon-fibre aircraft with a wingspan of up to 18 meters/ 59 feet, but weighing just 30 kg/ 66 pounds. By day it flies on solar power generated by amorphous silicon arrays on the wings that are no thicker than sheets of paper. By night it is powered by rechargeable lithium-sulphur batteries that are recharged during the day using solar power. Many of its design approaches and technologies will be leveraged for Vulture. At this point, illustrations and releases from Boeing depict a single aircraft approach.

The third competitor is Lockheed Martin. Details regarding their proposal and team are not available yet.

Other award competitors were not mentioned, but Aerovironment builds the hydrogen powered Global Observer with its 1 week flight times, and has considerable experience with very advanced high-altitude solar UAVs like the Pathfinder Plus and the record-setting Helios.

Contracts and Related Events

MarsFlyer
Zephyr Flight
(click to view full)

July 28-31/08: Zephyr breaks a world record with an 82 hour, 37 minute flight from Yuma Proving Grounds, AZ. Despite lift-sapping temperatures of up to 45 C/ 113 , Zephyr was flown on autopilot and via satellite communications to a maximum altitude of more than 60,000ft. The trial included a military utility assessment of a US Government communications payload.

The US DoD funded the demonstration flight under the Joint Capability Technology Demonstration (JCTD) program with the UK’s Ministry of Defence. JCTD projects are specially tailored to meet the needs of US combatant commands, and Zephyr is supported by USCENTCOM along with the Office of Secretary of Defense (OSD) for Advanced Systems and Concepts (AS&C) and the US Army Space and Missile Defense Command (SMDC). Qinetiq release.

April 21/08: Lockheed Martin is the 3rd firm to receive funding under the Vulture program. DARPA release [PDF]

April 21/08: Boeing announces a $3.8 million contract for Phase 1 of DARPA’s Vulture program. See above for details.

April 14/08: Aurora Flight Sciences announces an unspecified contract under DARPA’s Vulture program. See above for details. On April 23/08, AFS releases more information, revealing its Odysseus to be a 3-part vehicle rather than the single aircraft referenced in its earlier release.

Sept 10/07: QinetiQ’s Zephyr High Altitude Long Endurance (HALE) Unmanned Aerial Vehicle (UAV) breaks the official world record time for the longest duration unmanned flight, soaring for 54 hours to a maximum altitude of 58,355 feet over White Sands Missile Range in New Mexico. The current official FAI world record for unmanned flight was set by Northrop Grumman’s RQ-4A Global Hawk on March 22/01 at 30 hours 24 minutes – and since no FAI officials were present at White Sands, that record may stand.

New technologies tested on this Zephyr flifght included solar arrays supplied by United Solar Ovonic, a full flight-set of Sion Power batteries, and a novel solar-charger and bespoke autopilot developed by QinetiQ. QinetiQ release.

Additional Readings