Martin Marietta Model 845


The Martin Marietta Model 845 was a remotely piloted aircraft developed in the United States in the late 1960s and early 1970s for use as a communications relay in the Vietnam War.

Model 845
Role Communications relay drone
National origin United States
Manufacturer Martin Marietta
First flight April 1972
Primary user United States Air Force
Number built 3[1]

Design and developmentEdit

Two prototypes were built as part of the United States Air Force's Compass Dwell program, these machines also being based on a Schweizer SGS 1-34 sailplane and similar in configuration to the competing XQM-93 design by Ling-Temco-Vought. Test flights began in April 1972; during testing, one of the prototypes stayed aloft for almost 28 hours,[2] however it failed to meet the Air Force's requirement of a 40,000 feet (12,000 m) service ceiling.[1] In 1973 The Model 845A was cancelled (along with the XQM-93), the program being replaced by Compass Cope.[3]

Surviving airframesEdit

After the cancellation of the program, two 845 airframes were transferred by the Office of Naval Research to New Mexico Tech for use by the Langmuir Laboratory for Atmospheric Research, where they currently remain. Airframe 845A, which was converted into a piloted aircraft, was later used as a platform for atmospheric research. It continued flying as SPTVAR (Special Purpose Test Vehicle for Atmospheric Research) until the late 1990s. Its missions included flights over the Langmuir Laboratory facility in south-central New Mexico, flying through thunderstorms and making measurements of the electric field inside clouds.[4] The other airframe, still configured as the original drone design, is in storage at the same facility.

Specifications (variant)Edit

Data from [2]

General characteristics

  • Crew: None
  • Length: 25 ft 4.75 in (7.7407 m)
  • Wingspan: 59 ft 1.25 in (18.0150 m)
  • Height: 9 ft 6 in (2.90 m)
  • Gross weight: 2,320 lb (1,052 kg)
  • Powerplant: 1 × Lycoming TIO-360-A3B6 horizontally opposed piston engine, 200 hp (150 kW)


  • Maximum speed: 150 mph (240 km/h, 130 kn)
  • Endurance: 28 hours

See alsoEdit

Related development

Aircraft of comparable role, configuration, and era

Related lists


  1. ^ a b Aviation Week & Space Technology, Volume 98 (1973), page 67
  2. ^ a b Parsch, Andreas (2004). "Martin Marietta 845A". Directory of U.S. Military Rockets and Missiles Appendix 4: Undesignated Vehicles. Designation-Systems. Retrieved 2017-11-09.
  3. ^ Robinson, Anthony (1979). The Illustrated encyclopedia of aviation. Vol. 8. London: Marshall Cavendish. p. 854. ISBN 978-0856855818.
  4. ^ Winn, William (20 April 1993). "Aircraft Measurement of Electric Field: Self-Calibration". J. Geophys. Res. 98 (D4): 7351–7365. doi:10.1029/93JD00165.
  • This article contains material that originally came from the web article Unmanned Aerial Vehicles by Greg Goebel, which exists in the Public Domain.

External linksEdit