RM-86 Exos


Exos PWN-4A.jpg
Has useSounding rocket
ManufacturerUniversity of Michigan
Country of originUnited States
Height12.941 metres (42 ft 5.5 in)
Diameter580 millimetres (22.9 in)
Mass2,660 kilograms (5,870 lb)
Launch history
Launch sitesEglin AFB
Total launches10
First flightJune 26, 1958
Last flightNovember 2, 1965

The Exos, originally designated RM-86 and later PWN-4, was a sounding rocket developed by the University of Michigan and NACA for use by the United States Air Force.


Developed by the University of Michigan for use by the Air Force Cambridge Research Center, Exos used a three-stage configuration, consisting of a first-stage rocket from an Honest John rocket, a second stage from a Nike-Ajax surface-to-air missile, and a Thiokol XM19 upper stage.[1] It was designated XRM-86 in April 1959, and redesignated PWN-4A in June 1963.[2]

Utilising a rail launcher, the first launch of a full Exos vehicle took place in June 1958,[2] launched from the Wallops Flight Facility.[3] Eight operational launches took place between 1960 and 1965, launched from Eglin Air Force Base.[4]

Launch history

Date (UTC) Rocket Launch site Apogee Outcome Mission[4]
26 June 1958 Exos Wallops Island 370 kilometres (230 mi) Success Test launch
25 September 1958 Exos Wallops Island 460 kilometres (290 mi) Success Test launch
19 February 1960 Exos Eglin AFB 37 kilometres (23 mi) Failure Chemical release research
11 August 1961 Exos Eglin AFB 114 kilometres (71 mi) Success Ionospheric research
3 August 1962 Exos Eglin AFB 365 kilometres (227 mi) Success Bipolar Probe ionospheric research
25 October 1962 Exos Eglin AFB 669 kilometres (416 mi) Success Ionospheric research
25 July 1963 Exos Eglin AFB 623 kilometres (387 mi) Success Ionospheric research
25 May 1965 Exos Eglin AFB 488 kilometres (303 mi) Success Ionospheric research
2 November 1965 Exos Eglin AFB 686 kilometres (426 mi) Success International Quiet Sun Year aeronomy mission



  1. ^ Skoog and Hall 1990, p.214.
  2. ^ a b Parsch 2002
  3. ^ Shortal 1978, p.581.
  4. ^ a b Wade, Mark. "Exos Archived 2003-09-04 at the Wayback Machine". Encyclopedia Astronautica. Accessed 2014-05-11.


  • Parsch, Andreas (2002). "University of Michigan RM-86/PWN-4 Exos". Directory of U.S. Military Rockets and Missiles. designation-systems.net. Retrieved 2014-05-11.
  • Shortal, Joseph Adams (1978). A New Dimension, Wallops Island Flight Test Range: The First Fifteen Years. Hampton, VA: National Aeronautics and Space Administration. ASIN B004VJHCKC.
  • Skoog, Å. Ingemar and R. Cargill Hall, ed. (1990). History of Rocketry and Astronautics: Proceedings of the Twelfth, Thirteenth and Fourteenth History Symposia of the International Academy of Astronautics. AAS History Series. 10. Springfield, Virginia: American Astronautical Society. ISBN 978-0-87703-329-5.