NASA 

National Aeronautics and 

Facts

Space Administration 

Dryden Flight Research Center 

P.O. Box 273

Edwards, California 93523 

Voice 661-276-3449 

FAX 661-276-3566 

pao@dfrc.nasa.gov FS-2003-03-069 DFRC 

Proteus

The Proteus is a unique aircraft designed as a high-altitude, long-duration telecommunications relay platform, with 

potential for use on atmospheric sampling and Earth monitoring science missions as well. It was designed by Burt Rutan, 

president of Scaled Composites, and built during 1997-98 at the firm's development facility in Mojave, Calif. Normally flown 

by two pilots in a pressurized cabin, the Proteus also has potential to perform its missions semi-autonomously. 

Aircraft Description 

The Proteus was designed to carry an 18-foot diameter telecommunications antenna system for relay of broadband 

data over major cities. Rutan’s design allows for Proteus, so named for the mythological Greek sea-god who could 

change his appearance at will, to be reconfigured for a variety of other missions as well, such as atmospheric research, 

reconnaissance/surveillance, commercial imaging, and launch of small space satellites. The aircraft is designed for 

extreme reliability and low operating costs, and to operate out of general aviation airports with minimal support. 

The Proteus features an unconventional tandem-wing, twin-boom configuration with two rear-mounted turbofan 

engines providing power. The aircraft features modular construction that allows payloads to be carried in a variety of 

locations. Removable tip sections can be added to or removed from the rear wing or the forward canards to tailor the 

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Proteus' aerodynamics for various external payloads or for 

maximum altitude. The main landing gear is set wide apart, 

allowing for large externally-mounted payloads to be 

carried under the fuselage. 

The aircraft is designed to cruise at altitudes from 

50,000 to more than 63,000 feet for up to 18 hours. Proteus' small cabin is pressurized to allow the flight crew a 

shirt-sleeve environment equivalent to an altitude of 

14,500 feet when the aircraft is at 55,000 feet, or 15,500 

feet at a 60,000-foot altitude. 

NASA Dryden’s ERAST Involvement 

The Proteus was conceived as an "optionally piloted" 

aircraft flown by a two-person crew for takeoff, climb to 

mission altitude, descent and landing, and then operated 

either by a single pilot, remotely from the ground, or 

autonomously when on station at mission altitude. 

To that end, NASA's Dryden Flight Research Center, 

under the Environmental Research Aircraft and Sensor 

Technology (ERAST) project, assisted Scaled Composites 

in development of a sophisticated station-keeping autopilot 

system that gave the Proteus a fully functional autonomous 

capability when on station. In addition, the ERAST project 

helped fund a satellite communications (SATCOM)-based 

uplink/downlink data system for aircraft and payload data. 

The SATCOM system has full over-the-horizon capability, 

allowing the aircraft to be controlled remotely from a 

distant ground-based control station via the SATCOM 

uplink/downlink. 

Developmental Flight Tests 

The Proteus began its flight test and development 

program in the summer of 1998 from Scaled Composites 

facility at the Mojave Airport. 

The aircraft set two milestones on its 16th flight in 

February, 1999 when it reached an altitude of 50,000 ft 

while carrying an operating science imaging payload, the 

Airborne Real-Time Imaging System (ARTIS) developed 

by HyperSpectral Sciences, Inc.(HSI). The small ARTIS 

camera, developed by HSI under NASA's ERAST project, 

was operated remotely by the flight crew, taking visual and 

near-infrared photos of the California desert near the 

Mojave Airport. The system provided near-real time 

images to a ground station. 

The SATCOM equipment, including avionics and 

antenna systems, performed flawlessly during Proteus' 

deployment to the Paris Air Show in the summer of 1999. 

Record Altitude Flights 

In October 2000, the Proteus set three world altitude 

records during envelope-expansion flights over 

California’s high desert. The records were certified by the 

Swiss-based international aviation record certification 

agency Federation Aeronautique Internationale. 

The first records were for a peak altitude of 63,245 

feet and sustained horizontal flight at 62,385 feet. On a 

second flight, the Proteus reached a peak altitude of 55,994 

feet while carrying a 1,000 kg (2,200 lb.) payload. All 

three records were certified for aircraft in the Class C-1E, 

Group III with gross weights of 12,500 lbs. or less. 

NASA Dryden supported Proteus envelope-expansion 

flights by providing full pressure suits for the pilots 

through the ERAST project. NASA’s Office of Earth 

Science joined the National Oceanic and Atmospheric 

Administration and the Department of Defense in funding 

the record-setting flights as part of their evaluation of the 

Proteus as an airborne platform for atmospheric science 

and remote sensing missions at altitudes up to 60,000 feet. 

Recent Milestones 

Since the record flights in 2000, the Proteus has 

continued its support of the international atmospheric 

science community. This sensor development work has 

included six different science campaigns spanning the 

United States and the Pacific Rim, from Japan to Virginia 

and the Caribbean to the North Pole. In addition, the 

Proteus has continued to work with other customers, 

including NASA and the United States Air Force, in the 

flight test of next-generation flight systems. Significant 

recent missions included: 

• March 2001 -- As part of the TRACE-P mission, 

Proteus gathers data over the North Pole. 

• March 11-16, 2002 -- Proteus serves as a surrogate 

UAV in a successful “Detect, See, and Avoid” flight 

test campaign involving “cooperative” transponderequipped aircraft under NASA’s ERAST program. 

• July 2002 -- Proteus team was part of NASA's Crystal 

FACE science campaign involving six aircraft and 

hundreds of scientists. 

• April 2003 – Proteus again serves as a surrogate UAV 

in a follow-on “Detect, See and Avoid” flight demonstration for NASA involving both cooperative and noncooperative (non-transponder-equipped) target aircraft. 

Proteus is maintained and flown by Scaled Composites and 

is available for research and evaluation purposes by NASA 

and other customers. 

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The ERAST Project 

The Environmental Research Aircraft and Sensor • 

Technology (ERAST) project is a NASA initiative to 

develop new technologies for civil use of remotely oper- • 

ated unmanned aerial vehicles (UAVs). • 

The primary focus of ERAST is to develop slow- • 

flying UAVs that can perform long-duration science • 

missions at altitudes above 60,000 feet. These missions • 

could include remote sensing for Earth sciences studies, • 

hyperspectral imaging for agriculture monitoring, tracking • 

of severe storms, and serving as telecommunications relay • 

platforms. • 

• A parallel effort headed by NASA Ames Research 

Center, Moffett Field, Calif., developed lightweight, 

microminiaturized sensors that can be carried by these •

aircraft for environmental research and Earth monitoring. 

Additional technologies considered by the joint • 

NASA-industry ERAST Alliance include lightweight • 

materials, avionics, aerodynamics, and other forms of 

propulsion suitable for extreme altitudes and duration. • 

Although ERAST Alliance members are responsible • for aircraft development and operation, NASA has primary 

responsibility for overall program leadership, major • funding, individual project management, development and • coordination of payloads. NASA also is working long-term 

issues with the Federal Aviation Administration and 

• developing technology to make operation of these remotely 

operated aircraft in national airspace practical. • 

Sponsored by the Office of Aerospace Technology at 

NASA Headquarters, ERAST is managed by the NASA • 

Dryden Flight Research Center, Edwards, Calif. 

Aircraft Specifications 

Wingspan: 77 ft, 7 in; 92 ft with removable tips

installed.

Wing area: 300 ft2

Canard span: 54.7 ft; 64.7 ft with removable tips

installed.

Canard area: 178.7 ft2

Length: 56.3 ft

Height: 17.6 ft (on landing gear)

Cabin dimensions: 9 ft long, 5 ft dia.

Crew: 2, single-pilot operation.

Empty weight: 5,900 lb

Gross weight: 12,500 lb; 15,800 lb in military usage.

Fuel capacity: 6,000 lb in fuselage, canard, and wing

tanks.

Flight control system: Conventional manual pushrod/

cable system with sidestick controllers; autopilot for

hands-off flight when on station.

Payload: 1,800 to 7,260 lb, depending on mission.

Electrical power: 19kw up to 30kw, depending on

payload requirements.

Propulsion: Two Williams Research/Rolls FJ44-2

turbofan engines, 2,300 lb thrust each.

Airspeed: 190 kt at 20,000 ft, 280 kt at 40,000 ft, true

air speed. Mach 0.42 at cruise.

Takeoff distance: 2,500 ft at maximum gross weight.

Rate of climb: 6,000 ft/min at 8,000 lb, 3,400 ft/min at

12,500 lb.

Altitude: Up to 65,000 ft at 7,000 lb; 58,000 ft at

12,500 lb.

Endurance: Up to 18 hr, depending on payload and

altitude.

Primary materials: All composite airframe, graphiteepoxy sandwich construction. Crew compartment is

grid-stiffened solid laminate construction.

March, 2003 

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