Thor-Agena
| Function | Expendable launch system |
|---|---|
| Country of origin | United States |
| Size | |
| Height | Thor-Agena A: 28 m (92 ft) Thor-Agena B: 31 m (102 ft) Thor-Agena D: 31 m (102 ft) |
| Diameter | 2.44 m (8 ft 0 in) |
| Mass | Thor-Agena A: 53,130 kg (117,130 lb) Thor-Agena B: 56,507 kg (124,577 lb) Thor-Agena D: 56,507 kg (124,577 lb) |
| Stages | 2 |
| Launch history | |
| Status | Retired |
| Launch sites | Vandenberg Air Force Base |
| Total launches | 145 |
| First flight | 21 January 1959 |
| Last flight | 17 January 1968 |
Thor-Agena was a series of orbital launch vehicles. The launch vehicles used the Douglas-built Thor first stage and the Lockheed-built Agena second stages. They are thus cousins of the more-famous Thor-Deltas, which founded the Delta rocket family.
The first attempted launch of a Thor-Agena was in January 1959. The first successful launch was on 28 February 1959, launching Discoverer 1. It was the first two-stage launch vehicle to place a satellite into orbit.