Directory of U.S. Military Rockets and Missiles
Appendix 1: Early Missiles and Drones
Copyright © 2003 Andreas Parsch

Sylvania Electric SAM-A-19 Plato

In 1951, the U.S. Army defined the characteristics of a future mobile SAM-A-19 AMM (Anti-Missile Missile) system to protect field forces from attacks by short- and medium-range ballistic missiles (the modern term for this AMM would be TBMD - Theater Ballistic Missile Defense). In 1952, the SAM-A-19 program was formally begun as project Plato. Design studies were done by Sylvania Electric and Cornell Aeronautical Lab from 1953 to 1956, and in September 1956, the U.S. Army selected Sylvania's XSAM-A-19 design as the base for further development. The Plato missile was designed for speeds of Mach 6 to 8, and therefore one main focus of the initial studies were the aerodynamic and thermodynamic problems of hypersonic flight.

Component development for Plato continued until February 1959, when the program was cancelled before any prototypes had been built. As an interim measure, it was then decided to upgrade the SAM-A-25/MIM-14 Nike Hercules with a very limited anti-missile capability. As a long-term Plato replacement project, the Army began the FABMDS (Field Army Ballistic Missile Defense System) program, but this was also cancelled after only three years of design studies.

Note: Readily available public information on Plato is extremely limited. In fact, the U.S. Army's official historical monograph on Plato (Mary T. Cagle & Ruth Jarrell: "History of the PLATO Antimissile Missile System, 1952-1960") is still classified after more than 40 years. This is remarkable, because approximately 20 similar monographs about other Army missiles of that time, including nuclear ones, have been declassified for quite some time now. The author's request for declassification of the Plato monograph is pending.


No data on the physical characteristics of the planned SAM-A-19 missile are available.

Main Sources

[1] Redstone Arsenal Historical Information Website
[2] Plato-related NACA/NASA correspondence records (10 pages) at National Archives and Records Administration - Mid Atlantic Region, Philadelphia

Back to Directory of U.S. Military Rockets and Missiles, Appendix 1

Last Updated: 27 February 2003