| Function: | Sounding rocket |
| Manufacturer: | University of Michigan |
| Country-Origin: | United States |
| Height: | 42feet |
| Diameter: | 22.9inches |
| Mass: | 5870lb |
| Stages: | Three |
| Status: | Retired |
| Sites: | Eglin AFB |
| Launches: | 10 |
| Success: | 9 |
| Fail: | 1 |
| First: | June 26, 1958 |
| Last: | November 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, launched from the Wallops Flight Facility.[3] Eight operational launches took place between 1960 and 1965, launched from Eglin Air Force Base.[4]
| Date (UTC) | Rocket | Launch site | Apogee | Outcome | Mission | |
|---|---|---|---|---|---|---|
| 26 June 1958 | Exos | Test launch | ||||
| 25 September 1958 | Exos | Wallops Island | Test launch | |||
| 19 February 1960 | Exos | Chemical release research | ||||
| 11 August 1961 | Exos | Eglin AFB | Ionospheric research | |||
| 3 August 1962 | Exos | Eglin AFB | Bipolar Probe ionospheric research | |||
| 25 October 1962 | Exos | Eglin AFB | Ionospheric research | |||
| 25 July 1963 | Exos | Eglin AFB | Ionospheric research | |||
| 25 May 1965 | Exos | Eglin AFB | Ionospheric research | |||
| 2 November 1965 | Exos | Eglin AFB | International Quiet Sun Year aeronomy mission |