The Signe 3 satellite was a joint project between CNES and the USSR. It was built by Matra in collaboration with the CNRS research agency for the Diamant satellite program, and was originally called D2B Gamma. When the Diamant program was terminated the satellite was renamed Signe (the Russians called it Sneg). The `3' indicated the highest level of joint French-Soviet cooperation, a dedicated Earth satellite; 1 and 2 represented sounding rockets and individual French instruments on Soviet satellites respectively, and Signe 2 experiments flew on Prognoz spacecraft. Signe reportedly stood for `Solar interplanetary gamma neutron experiment' although a French acronym is more likely. Signe 3 was launched by Kosmos-3M from the Kapustin Yar station in Jun 1977 and operated for two years.
| Signe 3 | |||
| Date | Time | Event | Orbit |
|---|---|---|---|
| 1977 Jun 17 | Launch by Kosmos-3M | KY | |
| 94.3 459 x 519 x 50.7 | |||
| 1978 late | Tape recorder failed | ||
| 1979 Jun 20 | Reentered | ||