The Evolution of Remotely Piloted Research Vehicles

Peter W. Merlin

For over a half century, NASA researchers have worked to make remotely piloted research vehicles to complement piloted aircraft, in the forms of furnishing cheap "quick look" design validations, under­taking testing too hazardous for piloted aircraft, and furnishing new research capabilities such as high-altitude solar-powered environmental monitoring. The RPRV has evolved to sophisticated fly-by-wire inherently unstable vehicles with composite structures and integrated propulsion.

INCE THE MID-1 990S, researchers at the National Aeronautics and Space Administration (NASA) have increasingly relied on unmanned aerial vehicles (UAV s) to fill roles traditionally defined by piloted aircraft. Instead of strapping themselves into the cockpit and taking off into the unknown, test pilots more often fly remotely piloted research vehicles (RPRVs) from the safety of a ground-based control sta­tion. Such craft are ideally suited to serve as aerodynamic and systems testbeds, airborne science platforms, and launch aircraft, or to explore unorthodox flight modes. NASA scientists began exploring the RPRV concept at Dryden Flight Research Center, Edwards, CA, in the 1960s. Since then, NASA RPRV development has contributed significantly to such technological innovations as autopilot systems, data links, and iner­tial navigation systems, among others. By the beginning of the 21st cen­tury, use of the once-novel RPRV concept had become standard practice.

There is no substitute—wind tunnel and computer modeling notwith­standing—for actual flight data. The RPRV provides real-world results while providing the ground pilot with precisely the same responsibilities and tasks as if he were sitting in a cockpit onboard a research airplane. As in piloted flight-testing, the remote pilot is responsible for perform­ing data maneuvers, evaluating vehicle and systems performance, and reacting to emergency situations.

A ground pilot may, in fact, be considered the most versatile ele­ment of an RPRV system. Since experimental vehicles are designed to

venture into unexplored engineering territory, the remote pilot may be called upon to repeat or abort a test point, or execute additional tasks not included in the original flight plan. Not all unmanned research vehicles require a pilot in the loop, but having one adds flexibility and provides an additional level of safety when performing hazardous maneuvers.[880]