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Volume 46 | Issue 7 | August 2004


photo: John Sharkey.

John Sharkey. NASA Photo

Dryden Workload is Shifting to UAVs

By Jay Levine
X-Press Editor

If it seems like uninhabited air vehicles are becoming a bigger and bigger part of Dryden's workload, that's because they are.

As more and more emphasis is placed on smaller, less expensive aircraft that can do the dull, dirty and dangerous jobs, so too is the role growing that Dryden will play in development of UAV flight systems and platform demonstrators. Work with drones, remotely piloted aircraft and autonomous vehicles has been ongoing at Dryden for nearly three decades. That work is the foundation of the Center's reputation for development of UAV technology and integration of new components, a reputation punctuated by the groundbreaking, Dryden-led Environmental Research Aircraft and Sensor Technology program that ended last year.

John Sharkey, Dryden program planning office director and a former ERAST program manager, said that UAVs currently account for 24 percent of the Center's business in fiscal 2004. That percentage more than doubles in fiscal 2005 and is expected to further increase to about 60 percent by the end of the decade.

With its people and its unique capabilities, Dryden continues to help blaze new trails in UAV research and testing. Recent examples include continued support of the combined Air Force-Defense Advanced Research Projects Agency X-45A UAV project and successful ventures into the hypersonic realm with the X-43A scramjet engine testbed.

But work being done at Dryden is not limited to vehicle research. Dryden researchers also are focusing on what's inside the UAVs - or, what will be inside in the future: intelligent flight control systems capable of monitoring and diagnosing the status of jet engines in flight. Center engineers also are examining those concepts in Propulsion Health Monitoring System research being conducted on an Air Force C-17. And in a related effort, a specially modified Dryden F-15 is being used to research flight controls that can compensate for damage or loss of a flight control surface in the Damage Adaptive Control Systems project, which has implications for both military and civilian aircraft safety.

In addition, the Center will assist with science mission demonstrations that utilize UAVs to peer into a hurricane's eye, research ozone depletion and support investigations of the thickness of the Antarctic ice sheets.

In a joint effort with the aviation industry, Dryden is leading research aimed at developing recommendations that will assist the Federal Aviation Administration in formulating regulations to govern UAVs' ability to fly routinely - and safely - in national airspace alongside piloted aircraft. Development of these regulations is considered the last major impediment to advances in commercial UAV business.

Through partnerships with the military, government agencies, industry and academia, Dryden is expanding its UAV work to enhance the Center's mission. UAV projects are well suited to Dryden's areas of expertise, which include space exploration, 21st-century aviation, science mission demonstrations and intelligent flight control systems, Sharkey said.

photo: Altair UAV.

The remotely piloted Altair UAV makes its first checkout flight June 9, 2003, at El Mirage, Calif. The Altair could be a big part of the changing landscape of Dryden's work.
NASA Photo / Tom Tschida

New Role

NASA budgets and projects illustrate Dryden's evolving role in 21st-century aerospace and areas in which future business opportunities for the Center appear to lie. The Agency-level Vehicle Systems Office framework offers several avenues for future Dryden participation, Sharkey said. UAVs are a major area of interest - particularly high-altitude, long-endurance UAV platforms like Pathfinder-Plus and the Helios Prototype. Other areas ripe with possibilities include supersonics, subsonics, autonomous or personal air vehicles, rotorcraft and flight systems demonstrations, he said.

As part of Dryden's developing role, flight and systems demonstrations will allow Dryden researchers to showcase skills in systems integration along with partners at Langley Research Center, Hampton, Va., and Glenn Research Center, Cleveland. Ames Research Center, Moffett Field, Calif., will be a key partner in research on intelligent flight controls. 

"It's a really significant role for us, and it's somewhat of a changing role because we've become the integrator of technologies from other centers," Sharkey said. "We go find the mission requirements, pull together technologies - propulsion technologies from Glenn, airframe technologies from Langley and intelligent flight control systems from Ames. We take those elements and integrate them into a flight test program and do the high-level technology demonstrations.

"It puts us in a technology-integration role. It used to be, here at Dryden, people would come and ask us to do the flight test of an X-31, X-29 - here's a project, now go fly it for us. The new role here is to define the flight test projects from the start, and that becomes the conduit in the integration of technology," he explained.

A new role can lead to new opportunities.

"We're thinking about our new role and we're working to identify the right opportunities for us to do flight demonstrations. It really takes teaming with the other centers to pull this off. It really does have to be done in the spirit of One NASA," Sharkey said.

In addition to private-sector interests and closer ties to other NASA centers, Sharkey said other government agencies such as the Federal Aviation Administration, the Department of Energy, Department of Defense and DARPA represent additional opportunities for partnering.

Dryden is currently assisting the Air Force and DARPA, for example, in efforts to reach new milestones with the X-45A. The Center may play a role in integrating common systems of both a later version of the X-45A and the Navy's X-47 as those projects mature (see related story), Sharkey said. New opportunities with the common operating systems of the X-45A and the X-47 could include research flights using Dryden piloted assets such as the G-3 (also know as a C-20) testbed aircraft to prove sensor technology for the common operating system. Development of common systems could mean a significant role for Dryden in the overall program to which the X-45A and the X-47 belong, the Joint Unmanned Combat Air System, or J-UCAS program.

Science Missions

The NASA science mission directorate is formulating changes in Dryden's airborne science program, which currently utilizes a DC-8 and two ER-2 aircraft. One potential change is transforming an ER-2 from a traditional, piloted platform to an aircraft that can fly in both piloted and unpiloted modes during the same mission - a first of its kind, Sharkey said.  This type of aircraft, the Optionally Piloted Vehicle, could open up new possibilities for future missions.

Engineers envision that the modified aircraft could fly farther and longer than a piloted aircraft. In such a scenario, a pilot would fly the aircraft to a science mission location. Once there, the aircraft would switch to unpiloted mode to fly the actual mission; this transitional approach would allow a pilot to continue flying the aircraft in national airspace until regulations governing UAVs in the airspace are firmly in place.

Such an ER-2 transitional platform could help the science community become acclimated to using UAVs and develop infrastructure required for their use. As other high-altitude, long-endurance UAVs become available, the new vehicles could travel the roads paved by the OPV hybrid, Sharkey said.

A principal goal will be development and use of new UAV platforms through partnerships with NASA's science mission directorate and aeronautics enterprise.

"The aeronautics and the science mission directorates have driven UAV development," Sharkey said. "Aeronautics can bridge the gap between UAV technology development and the needs of science mission users."

In the quest for high-altitude, long-endurance UAVs to be used in science missions, Sharkey said Dryden will be central to efforts to develop a Helios-class air vehicle. That vehicle's capabilities will include its use as a high-altitude UAV platform that can fly for weeks or months by integrating lightweight and low-airspeed airframe technologies with regenerative solar-electric propulsion and power technologies. Those technologies are expected to develop beginning with the Suborbital Long Endurance Observer project. The SOLEO aircraft is intended to be available for science missions, such as storm tracking, in 2009. Project officials envision SOLEO, a Dryden project, as being capable of tracking a storm from genesis to landfall, flights that could last for up to weeks and encompass hemispherical range over remote areas.

The consumable (probably liquid hydrogen) fuel-powered vehicle will be designed to fly continuously for 10 to 14 days at altitudes of about 60,000 feet. It might feature a reciprocating engine fueled by liquid hydrogen, or electric propulsion powered by an alternative energy source - a fuel cell or a hybrid internal combustion engine, he said. The exhaust produced by both fuel cell and internal combustion engines fueled by liquid hydrogen is water, a by-product that is environmentally preferable to the carbon monoxide produced by conventional aircraft. Such an aircraft would initially be designed to fly for two days then be extended to flights of two weeks and ultimately of months at a time, at 60,000 feet, by 2012, Sharkey said.

Development of a solar-powered regenerative fuel cell for the Helios Prototype is a follow-on goal for later stages of the project, he said. Solar regenerative technology development and integration are expected to be among technologies designed to enable the level of performance required for extreme-duration science missions. Sharkey said several federal agencies are interested in technology development leading to long-duration aircraft, including the National Oceanographic and Atmospheric Administration, the National Geospacial Agency (formerly called the National Imaging and Mapping Agency) and the Defense and Homeland Security departments.

Enhancement of sensor technologies for use in science missions on UAVs such as Altair or Global Hawk, or piloted platforms such as Proteus, is another key goal, he said. One such instrument is the repeat pass interferometer, a type of radar that gives extremely accurate imaging of Earth's surface as a host aircraft flies over an area using synthetic aperture radar, or SAR.

"If you can precisely control the trajectory of the UAV over a pass - let's say the San Andreas Fault through the Antelope Valley - the objective is to repeat that aircraft pass over the same trajectory within one to 10 meters of accuracy," Sharkey explained. "If the aircraft can fly down that tube accurately day in and day out, then the SAR can actually get centimeter- or subcentimeter-level resolution of the Earth's surface so it can be used for scientific measurements.

"That's an enhancement to an existing platform like Altair that would give it precision trajectory capabilities and allow scientists to go develop a repeat pass interferometer instrument," he said. A partnership with NASA's Jet Propulsion Laboratory in Pasadena aimed at development of such capabilities is under way.

Dryden also can assume some coordination efforts with civil aviation customers on work currently performed by the Air Force.

"There's an opportunity for Dryden to enhance the advanced-concept technology demonstrator versions of Global Hawk and provide access to civil missions, so the Air Force can focus on its primary mission," said Sharkey. "Efforts are under way to see if we can make that happen.

"In the future, we could take the existing Global Hawk and work with (Global Hawk builder) Northrop Grumman to develop its capability for science missions and provide access to the civil community," he continued. "Because it was developed for a specific military purpose, engineering changes are necessary to make it a good platform for scientists and other customers. We see an opportunity in being able to provide a suite of aircraft like Altair, for which we have a lease. We're also in the planning stages of acquiring an advanced UAV testbed to complement Altair, and use it as an in-house UAV flight and systems demonstration testbed - like we use the F-18 Systems Research Aircraft for piloted air vehicle technologies."

The NOAA, the Department of Energy, the U.S Geological Survey, the Environmental Protection Agency, the National Geospacial Agency and the Department of Homeland Security are among agencies that have expressed an interest in UAV aircraft. Dryden is working toward developing capabilities to meet those customers' specialized needs, he said.

Regenerative fuel cell technology fits into the Defense Department's interests, plays a role in DARPA's look at a morphing-wing aircraft and is integral to how a global observation system could impact climate prediction and global warming research for organizations such as the Scripps Institute of Oceanography.

The Scripps Institute, based in La Jolla, Calif., recently hosted a workshop attended by representatives of NASA, the DOE and NOAA. At that event, attendees discussed how a UAV network might be able to use a combination of remote sensing and in situ (direct physical measurements in real time) monitoring to fill a void in the existing body of knowledge about the global climate change and the Earth's ozone layer. That constitutes one area in which Dryden could work toward development of a UAV platform, along with tapping NASA's resources for sensor technology development for a mission that fills in gaps in climate prediction, Sharkey said.

"NOAA and DOE envision a highly integrated network of UAVs to go out and get observational data through both remote sensing and in situ measurements, which they need all across the globe to fill in data voids that currently exist in the observation systems. Satellites give you big global pictures, but not the high-resolution detail information," he said.

Opportunities for work in this project area are substantial, Sharkey said. Success in such efforts could lead to a partnership for Dryden similar to the one NOAA currently has with Goddard Space Flight Center in Greenbelt, Md., for satellite development. Long-term opportunities to develop operational requirements for NOAA UAVs could mean annual revenues of $50 to $100 million, he said. A Memorandum of Understanding exists between Dryden and the NOAA Office of Oceanic and Atmospheric Research in Boulder, Colo., but a new agency-level agreement for research and development phases would be required in addition to the MOA.

Just as the Defense Department released a UAV "roadmap" in 2001 and a revised one in 2002, a civil aviation UAV roadmap is now being developed within the Earth Science Mission Capabilities project at Dryden that will analyze mission needs and concepts, Sharkey said.

Another activity that will require specialized UAV aircraft are the "small, low and slow" science missions - missions that will investigate the thickness of ice in Antarctica, offer the Department of Homeland Security urban-surveillance capabilities or fly hazardous missions from which this breed of UAVs would not be expected to return, such as in bio-hazard, volcano and hurricane studies.

As plans begin solidifying in all these areas, Sharkey reiterated that the challenge ahead is to meet customer needs and form beneficial partnerships. Dryden's success in leading the development of UAV platforms and sensors will help the Center retain its reputation as a leader in UAV technology and an agent through which civil agencies may gain access to the technology tools they need to succeed in their missions.

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