Directory of U.S. Military Rockets and Missiles
Appendix 4: Undesignated Vehicles
Copyright © 2004 Andreas Parsch

Republic SD-3 Snooper

In 1957, Republic won an industry-wide competition for a short-range reconnaissance drone for the U.S. Army. The complete drone system including ground equipment was designated AN/USD-3. The drone itself, named Snooper, was referred to either also as AN/USD-3 or simply as SD-3 (with "SD" usually being interpreted as "Surveillance Drone"). The first flight of the SD-3 occured in January 1959.

Photo: Republic

The AN/USD-3 drone was of twin-boom pusher layout, and powered by a Continental IO-200 piston engine. It was launched from a zero-length launcher with the help of two solid-propellant rocket boosters. It landed with a parachute recovery system, and was equipped with inflatable bags to ensure soft landings. The SD-3 either followed a pre-programmed course or was controlled from the ground by radio commands. It had a quickly changeable nose section, which could house one of a variety of payload options, including photographic, infrared, radar or TV reconnaissance systems.

Photo: U.S. Army

A total of 50 Snooper vehicles were built for evaluation by the U.S. Army, but in the end the AN/USD-3 system did not enter operational service.


Note: Data given by several sources show slight variations. Figures given below may therefore be inaccurate!

Data for SD-3:

Length4.65 m (15 ft 3 in)
Wingspan3.40 m (11 ft 2 in)
Weight450 kg (1000 lb)
Speed480 km/h (300 mph)
Ceiling6100 m (20000 ft)
Range160 km (100 miles)
PropulsionContinental IO-200 piston engine

Main Sources

[1] Joshua Stoff: "The Thunder Factory", Motorbooks Intl., 1990
[2] Norman J. Bowman: "The Handbook of Rockets and Guided Missiles", Perastadion Press, 1963
[3] Frederick I. Ordway III, Ronald C. Wakeford: "International Missile and Spacecraft Guide", McGraw-Hill, 1960

Back to Directory of U.S. Military Rockets and Missiles, Appendix 4

Last Updated: 5 May 2004