| Function: | Expendable launch system |
| Country-Origin: | United States |
| Sites: | Vandenberg, SLC-2E |
| Launches: | 1 |
| Success: | 1 |
| Status: | Retired |
| Only: | 4 July 1968 |
The Delta J or Thor-Delta J was an American expendable launch system of the late 1960s. Only one was launched, with the Explorer 38 spacecraft. It was a member of the Delta family of rockets.
The Delta J was derived from the Delta E. The first stage was a Thor missile in the DSV-2C configuration, with three Castor-1 solid rocket boosters clustered around it. A Delta E was used as the second stage. The Altair third stage of the Delta E was replaced with the more powerful Star 37D SRM.
The only Delta J to fly was launched from Vandenberg Air Force Base, Space Launch Complex 2E on 4 July 1968. It successfully placed the Explorer 38 satellite into medium Earth orbit.[1] [2]