|Manufacturer||University of Michigan|
|Country of origin||United States|
|Height||12.941 metres (42 ft 5.5 in)|
|Diameter||580 millimetres (22.9 in)|
|Mass||2,660 kilograms (5,870 lb)|
|Launch sites||Eglin AFB|
|First flight||June 26, 1958|
|Last flight||November 2, 1965|
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. It was designated XRM-86 in April 1959, and redesignated PWN-4A in June 1963.
Utilising a rail launcher, the first launch of a full Exos vehicle took place in June 1958, launched from the Wallops Flight Facility. Eight operational launches took place between 1960 and 1965, launched from Eglin Air Force Base.
|Date/Time (GMT)||Rocket||Launch site||Outcome||Apogee||Mission|
|1958-06-26||Exos||Wallops Island||Success||370 kilometres (230 mi)||Test launch|
|1958-09-25||Exos||Wallops Island||Success||460 kilometres (290 mi)||Test launch|
|1960-02-19||Exos||Eglin AFB||Failure||Apogee 37 kilometres (23 mi)||Chemical release research|
|1961-08-11||Exos||Eglin AFB||Success||Apogee 114 kilometres (71 mi)||Ionospheric research|
|1962-08-03||Exos||Eglin AFB||Success||Apogee 365 kilometres (227 mi)||Bipolar Probe ionospheric research|
|1962-10-25||Exos||Eglin AFB||Success||Apogee 669 kilometres (416 mi)||Ionospheric research|
|1963-07-25||Exos||Eglin AFB||Success||Apogee 623 kilometres (387 mi)||Ionospheric research|
|1965-05-25||Exos||Eglin AFB||Success||Apogee 488 kilometres (303 mi)||Ionospheric research|
|1965-11-02||Exos||Eglin AFB||Success||Apogee 686 kilometres (426 mi)||International Quiet Sun Year aeronomy mission|
- Skoog and Hall 1990, p.214.
- Parsch 2002
- Shortal 1978, p.581.
- Wade, Mark. "Exos". 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 978-0877033295.