The LES (Lincoln Experimental Satellite) series were spacecraft designed and built by the Massachusetts Institute of Technology Lincoln Laboratory as part of the Lab's Air Force-sponsored program in space communications. Their goal was to test realistically, in orbit, new devices and techniques developed for possible use in satellite communication systems. LES-5 was designed to aid in the development of a tactical satellite communication system for the Department of Defense and was used for the first-ever satellite communications among Army, Navy, and Air Force units. All spacecraft in the LES series were launched from Cape Canaveral.

 

spacecraft	launch date	launch vehicle	orbit	mass (kg)
LES 1	Feb 11, 1965	Titan IIIA	2,783 × 2,809 km × 32.1°	31
LES 2	May 6, 1965	Titan IIIA	2,771 × 14,810 km × 32.2°	37
LES 3	Dec 21, 1965	Titan IIIC	267 × 4,829 km × 26.5°	16
LES 4	"	"	189 × 33,632 km × 26.6°	52
LES 5	Jul 1, 1967	Titan IIIC	33,188 × 33,618 km × 11.6°	194
LES 6	Sep 26, 1968	Titan IIIC	35,771 × 35,847 km × 13.0°	163
LES 8	Mar 15, 1976	Titan IIIC	35,687 × 35,886 km × 17.0°	454
LES 9	"	"	35,745 × 35,825 km × 17.0°	454