EXPLORER 39
| Launched | 7 August 1968 |
| Flight ended | 21 June 1981 |
| Status | Decayed |
| Launch site | Air Force Western Test Range, California, USA |
| Owner | United States |
| NORAD ID | 3337 |
| COSPAR ID | 1968-066A |
| Alternative names |
ADI-3 |
| Observing |