Status: Study 1995. Payload: 70 kg (154 lb). Gross mass: 310 kg (680 lb).

Up to 48 of these 310-kg spacecraft (12 satellites in each of four orbital planes) were to fly at altitudes of 1,500 km with inclinations of 74 degrees.

Launches would be conducted either by Kosmos-2 boosters with two spacecraft or by Tsyklon-3 boosters with six spacecraft. The long and narrow spacecraft would have a payload capacity of 70 kg and a design lifetime of six years. The design included UHF, L-band, and Ku- band transponders. Like several of its competitors, Signal suffered program delays, and the launch of the first prototype spacecraft slipped until at least 1995. It then slipped from sight.