Thor DM-21 Agena-B or just Thor-Agena was a series of orbital launch vehicles. The rockets 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 DM-21 Agena-B was in January 1959. The first successful launch was on 28 February 1959, launching Discoverer 17.[1]
| Date/Time (UTC) | Rocket | S/N | Launch Site | Payload | Function | Orbit | Outcome | Remarks |
|---|---|---|---|---|---|---|---|---|
| 1960-10-26 20:26 | Thor DM-21 Agena-B | Thor 253 Agena 1061 | VAFB LC-75-3-4 | Discoverer 16 | Reconnaissance | LEO | Maiden flight of Thor-Agena B. Agena staging failed. Vehicle fell into the Pacific Ocean. | |
| 1960-11-12 20:43 | Thor DM-21 Agena-B | Thor 297 Agena 1062 | VAFB LC-75-3-5 | Discoverer 17 | Reconnaissance | LEO | ||
| 1960-12-07 20:20:58 | Thor DM-21 Agena-B | Thor 296 Agena 1103 | VAFB LC-75-3-4 | Discoverer 18 | Reconnaissance | LEO | ||
| 1960-12-20 20:32 | Thor DM-21 Agena-B | Thor 258 Agena 1101 | VAFB LC-75-3-5 | Discoverer 19 | Technology | LEO | ||
| 1961-02-17 20:25 | Thor DM-21 Agena-B | Thor 298 | VAFB LC-75-3-4 | Discoverer 20 | Reconnaissance | LEO | ||
| 1961-02-18 22:58 | Thor DM-21 Agena-B | Thor 261 Agena 1102 | VAFB LC-75-3-5 | Discoverer 21 | Technology | LEO | ||
| 1961-03-30 20:34:43 | Thor DM-21 Agena-B | Thor 300 Agena 1105 | VAFB LC-75-3-4 | Discoverer 22 | Reconnaissance | LEO | Agena control failure. | |
| 1961-04-08 19:21 | Thor DM-21 Agena-B | Thor 307 Agena 1106 | VAFB LC-75-3-5 | Discoverer 23 | Reconnaissance | LEO | ||
| 1961-06-08 21:16 | Thor DM-21 Agena-B | Thor 302 Agena 1108 | VAFB LC-75-3-4 | Discoverer 24 | Reconnaissance | LEO | Agena power failure | |
| 1961-06-16 23:02 | Thor DM-21 Agena-B | Thor 303 Agena 1107 | VAFB LC-75-1-1 | Discoverer 25 | Reconnaissance | LEO | ||
| 1961-07-07 23:29:48 | Thor DM-21 Agena-B | Thor 308 Agena 1109 | VAFB LC-75-3-5 | Discoverer 26 | Reconnaissance | LEO | ||
| 1961-07-21 22:35 | Thor DM-21 Agena-B | Thor 322 Agena 1110 | VAFB LC-75-3-4 | Discoverer 27 | Reconnaissance | LEO | Open circuit in guidance computer led to loss of control and vehicle breakup at T+60 seconds. | |
| 1961-08-04 00:01 | Thor DM-21 Agena-B | Thor 309 Agena 1111 | VAFB LC-75-1-1 | Discoverer 28 | Reconnaissance | LEO | Agena control system malfunctioned | |
| 1961-08-30 20:00 | Thor DM-21 Agena-B | Thor 323 Agena 1112 | VAFB LC-75-3-4 | Discoverer 29 | Reconnaissance | LEO | ||
| 1961-09-12 19:59 | Thor DM-21 Agena-B | Thor 310 Agena 1113 | VAFB LC-75-3-5 | Discoverer 30 | Reconnaissance | LEO | ||
| 1961-09-17 21:00 | Thor DM-21 Agena-B | Thor 324 Agena 1114 | VAFB LC-75-1-1 | Discoverer 31 | Reconnaissance | LEO | ||
| 1961-10-13 19:22 | Thor DM-21 Agena-B | Thor 328 Agena 1115 | VAFB LC-75-3-4 | Discoverer 32 | Reconnaissance | LEO | 100th Thor launch | |
| 1961-10-23 19:23 | Thor DM-21 Agena-B | Thor 329 Agena 1116 | VAFB LC-75-3-5 | Discoverer 33 | Reconnaissance | LEO | Agena hydraulics failure | |
| 1961-11-05 20:00 | Thor DM-21 Agena-B | Thor 330 Agena 1117 | VAFB LC-75-1-1 | Discoverer 34 | Reconnaissance | LEO | Incorrect guidance program left the satellite in a useless orbit. | |
| 1961-11-15 21:23 | Thor DM-21 Agena-B | Thor 326 Agena 1118 | VAFB LC-75-3-4 | Discoverer 35 | Reconnaissance | LEO | ||
| 1961-12-12 20:40 | Thor DM-21 Agena-B | Thor 325 Agena 1119 | VAFB LC-75-3-4 | Discoverer 36 Oscar 1 | Reconnaissance Amateur radio satellite | LEO | ||
| 1962-01-13 21:41 | Thor DM-21 Agena-B | Thor 327 Agena 1120 | VAFB LC-75-3-4 | Discoverer 37 | Reconnaissance | LEO | Agena restart burn failed. | |
| 1962-02-21 18:44 | Thor DM-21 Agena-B | Thor 332 Agena 2301 | VAFB LC-75-3-5 | FTV 2301 | ELINT | LEO | Upper stage failed to restart for circularization burn | |
| 1962-02-27 19:39 | Thor DM-21 Agena-B | Thor 241 Agena 1123 | VAFB LC-75-3-4 | Discoverer 38 | Reconnaissance | LEO | ||
| 1962-04-18 00:54 | Thor DM-21 Agena-B | Thor 331 Agena 1124 | VAFB LC-75-3-5 | Discoverer 39 | Reconnaissance | LEO | ||
| 1962-04-29 00:30:12 | Thor DM-21 Agena-B | Thor 333 Agena 1125 | VAFB LC-75-3-4 | FTV 1125 | Reconnaissance | LEO | ||
| 1962-05-15 19:36 | Thor DM-21 Agena-B | Thor 334 Agena 1126 | VAFB LC-75-3-5 | FTV 1126 | Reconnaissance | LEO | ||
| 1962-05-30 01:00:04 | Thor DM-21 Agena-B | Thor 336 Agena 1128 | VAFB LC-75-1-1 | FTV 1128 | Reconnaissance | LEO | ||
| 1962-06-02 00:31 | Thor DM-21 Agena-B | Thor 335 Agena 1127 | VAFB LC-75-3-4 | FTV 1127 Oscar 2 | Reconnaissance Amateur radio | LEO | ||
| 1962-06-18 20:20 | Thor DM-21 Agena-B | Thor 343 Agena 2312 | VAFB LC-75-3-5 | FTV 2312 | ELINT | LEO | ||
| 1962-06-23 00:30 | Thor DM-21 Agena-B | Thor 339 Agena 1129 | VAFB LC-75-3-4 | FTV 1129 | Reconnaissance | LEO | ||
| 1962-07-21 00:56 | Thor DM-21 Agena-B | Thor 342 Agena 1130 | VAFB LC-75-3-5 | FTV 1130 | Reconnaissance | LEO | ||
| 1962-07-28 00:30 | Thor DM-21 Agena-B | Thor 347 Agena 1131 | VAFB LC-75-3-4 | FTV 1131 | Reconnaissance | LEO | ||
| 1962-09-01 20:39 | Thor DM-21 Agena-B | Thor 348 Agena 1132 | VAFB LC-75-3-5 | FTV 1132 | Reconnaissance | LEO | ||
| 1962-09-17 23:46 | Thor DM-21 Agena-B | Thor 350 Agena 1133 | VAFB LC-75-3-4 | FTV 1133 ERS-2 | Reconnaissance Technology | LEO | ||
| 1962-09-29 06:05 | Thor DM-21 Agena-B | Thor 341 TA-1 | VAFB LC-75-1-1 |  Alouette 1TAVE | Ionospheric Technology | LEO | ||
| 1962-10-09 18:35 | Thor DM-21 Agena-B | Thor 352 Agena 1134 | VAFB LC-75-3-4 | FTV 1134 | Reconnaissance | LEO | ||
| 1962-11-05 22:04 | Thor DM-21 Agena-B | Thor 356 Agena 1136 | VAFB LC-75-3-4 | FTV 1136 | Reconnaissance | LEO | ||
| 1962-11-24 22:01 | Thor DM-21 Agena-B | Thor 367 Agena 1135 | VAFB LC-75-3-4 | FTV 1135 | Reconnaissance | LEO | ||
| 1963-01-16 21:59 | Thor DM-21 Agena-B | Thor 363 Agena 2313 | VAFB LC-75-3-5 | OPS 0180 | ELINT | LEO | ||
| 1965-11-29 04:48 | Thor DM-21 Agena-B | Thor 453 Agena 6102 | VAFB LC-75-1-1 | Alouette 2 / Explorer 31 (DME) | Ionospheric research satellite / Ionospheric research satellite | MEO | ||