# List of failed Thor and Delta launches

This is a list of failed launches of rockets in the Thor and Delta rocket family. copied content from [[List of Thor and Delta launches (1957&#x2D;1959)]], [[List of Thor and Delta launches (1960&#x2D;1969)]], [[List of Thor and Delta launches (1970&#x2D;1979)]], [[List of Thor and Delta launches (1980&#x2D;1989)]], [[List of Thor and Delta launches (1990&#x2D;1999)]], [[List of Thor and Delta launches (2000&#x2D;2009); see those pages history for attribution The Thor and Delta family rockets have had 51 complete failures, 10 partial failures, and 1 partial success, for a total of 62 unsuccessful Thor and Delta family missions. Since it has had 768 launches, 79+314+117+58+89+72+37+2 this gives it a reliability of 91.9%, which puts it within the average range for rockets that started around the space age.

## Launch attempts

The data in this table comes from in addition to the references listed within the table. :
| 1957-1959 | 1957-1959 | 1957-1959 | 1957-1959 | 1957-1959 | 1957-1959 | 1957-1959 | 1957-1959 | 1957-1959 |
| Date/Time (UTC) | Rocket | S/N | Launch Site | Payload | Function | Orbit | Outcome | Remarks |
| 1957-01-26 | Thor DM-18 | Thor 101 | CCAFS LC-17B | | Missile test | Suborbital | Failure | Maiden flight of Thor, first launch from LC-17. Contaminated LOX caused loss of thrust at liftoff. Vehicle fell back onto the pad and exploded. |
| 1957-04-20 04:33 | Thor DM-18 | Thor 102 | CCAFS LC-17B | | Missile test | Suborbital | Failure | RSO sent a mistaken destruct command at T+35 seconds due to an incorrect console readout. |
| 1957-08-30 | Thor DM-18 | Thor 104 | CCAFS LC-17A | | Missile test | Suborbital | Failure | |
| 1957-10-03 17:14 | Thor DM-18 | Thor 107 | CCAFS LC-17A | | Missile test | Suborbital | Failure | Stuck valve prevented the gas generator from starting. Missile fell back onto the pad and exploded. |
| 1957-10-11 16:33 | Thor DM-18 | Thor 108 | CCAFS LC-17B | | Missile test | Suborbital | Partial success | Turbopump failure at T+152 seconds. Flight considered a "partial success". |
| 1960-1969 |||||||||
| Date/Time (UTC) | Rocket | S/N | Launch Site | Payload | Function | Orbit | Outcome | Remarks |
| 1960-02-04 18:51:45 | Thor DM-18 Agena-A | Thor 218 Agena 1052 | VAFB LC-75-3-4 | Discoverer 9 | Reconnaissance | LEO | Failure | Premature Thor cutoff. Agena could not attain orbital velocity. |
| 1960-02-19 20:15:14 | Thor DM-18 Agena-A | Thor 223 Agena 1054 | VAFB LC-75-3-5 | Discoverer 10 | Reconnaissance | LEO | Failure | Thor flight control malfunction. RSO T+52 seconds. |
| 1960-05-13 09:16:05 | Thor DM-19 Delta | Thor 144 Delta 1 | CCAFS LC-17A | Echo 1 | Communication | MEO | Failure | Maiden flight of Thor-Delta, upper-stage attitude control system malfunctioned |
| 1960-06-29 22:00:44 | Thor DM-18 Agena-A | Thor 160 Agena 1053 | VAFB LC-75-3-4 | Discoverer 12 | Reconnaissance | LEO | Failure | Agena attitude control malfunction. |
| 1960-08-18 19:58 | Thor DM-21 Ablestar | Thor 262 Ablestar 004 | CCAFS LC-17B | Courier 1A | Communications | LEO | Failure | Premature first stage cutoff. RSO T+150 seconds. |
| 1960-10-26 20:26 | Thor DM-21 Agena-B | Thor 253 Agena 1061 | VAFB LC-75-3-4 | Discoverer 16 | Reconnaissance | LEO | Failure | Maiden flight of Thor-Agena B. Agena staging failed. Vehicle fell into the Pacific Ocean. |
| 1960-11-30 19:50 | Thor DM-21 Ablestar | Thor 283 Ablestar 006 | CCAFS LC-17B | Transit 3A GRAB-2 (Solrad-2) | Navigation ELINT | LEO | Failure | Premature Thor cutoff. RSO. Debris fell in Cuba. |
| 1961-03-30 20:34:43 | Thor DM-21 Agena-B | Thor 300 Agena 1105 | VAFB LC-75-3-4 | Discoverer 22 | Reconnaissance | LEO | Failure | Agena control failure. |
| 1961-06-08 21:16 | Thor DM-21 Agena-B | Thor 302 Agena 1108 | VAFB LC-75-3-4 | Discoverer 24 | Reconnaissance | LEO | Failure | Agena power failure |
| 1961-07-21 22:35 | Thor DM-21 Agena-B | Thor 322 Agena 1110 | VAFB LC-75-3-4 | Discoverer 27 | Reconnaissance | LEO | Failure | 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 | Failure | Agena control system malfunctioned |
| 1961-10-23 19:23 | Thor DM-21 Agena-B | Thor 329 Agena 1116 | VAFB LC-75-3-5 | Discoverer 33 | Reconnaissance | LEO | Failure | 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 | Failure | Incorrect guidance program left the satellite in a useless orbit. |
| 1962-01-13 21:41 | Thor DM-21 Agena-B | Thor 327 Agena 1120 | VAFB LC-75-3-4 | Discoverer 37 | Reconnaissance | LEO | Failure | Agena restart burn failed. |
| 1962-01-24 09:30 | Thor DM-21 Ablestar | Thor 311 Ablestar 010 | CCAFS LC-17B | LOFTI-2A SECOR GRAB-4 (Solrad 4) Injun 2 SURCAL 1 | Technology Geodesy ELINT Ionospheric Calibration | LEO | Failure | Second stage insufficient thrust |
| 1962-02-21 18:44 | Thor DM-21 Agena-B | Thor 332 Agena 2301 | VAFB LC-75-3-5 | FTV 2301 | ELINT | LEO | Partial failure | Upper stage failed to restart for circularization burn |
| 1962-05-10 12:06 | Thor DM-21 Ablestar | Thor 314 Ablestar 011 | CCAFS LC-17B | ANNA 1A | Geodesy | LEO | Failure | Second stage failed to ignite |
| 1962-06-04 09:44:17 | Thor DSV-2E | Thor 199 | Johnston LE-1 | Bluegill | Nuclear test | Suborbital | Failure | Radar contact lost 5 minutes after launch. RSO destruct command sent. |
| 1962-06-20 08:46:16 | Thor DSV-2E | Thor 193 | Johnston LE-1 | STARFISH | Nuclear test | Suborbital | Failure | RVs caused turbine exhaust gas to enter the thrust section, overheating and weakening the engine mounts. Engine broke loose and ruptured the propellant tanks T+59 seconds. Warhead destroyed by RSO T+65 seconds. |
| 1962-07-26 09:13:53 | Thor DSV-2E | Thor 180 | Johnston LE-1 | Bluegill Prime | Nuclear test | Suborbital | Failure | Stuck LOX valve caused loss of thrust and fire on the launch stand. Range Safety Officer destroyed the missile and warhead. Launch area extensively contaminated with plutonium. |
| 1962-10-16 09:14:38 | Thor DSV-2E | Thor 156 | Johnston LE-2 | Bluegill Double Prime | Nuclear test | Suborbital | Failure | Flight control failure T+85 seconds. RSO T+156 seconds. |
| 1963-02-28 21:48 | TAT SLV-2A Agena-D | Thor 354 Agena 1159 | VAFB LC-75-3-5 | OPS 0583 | Reconnaissance | LEO | Failure | Maiden flight of Thrust-Augmented Thor Agena. One SRB failed to ignite and subsequently separate from the vehicle, resulting in loss of control and self-destruct T+127 seconds. |
| 1963-03-18 21:13 | TAT SLV-2A Agena-D | Thor 360 Agena 1164 | VAFB LC-75-3-4 | OPS 0627 | Reconnaissance | LEO | Failure | Electrical short at staging causes loss of Agena control and no orbit. |
| 1963-04-26 20:13 | Thor DM-21 Agena-D | Thor 372 Agena 1411 | VAFB LC-75-1-1 | OPS 1008 | Reconnaissance | LEO | Failure | Attitude sensor alignment error results in no Agena orbit. |
| 1963-11-09 20:27:54 | Thor SLV-2 Agena-D | Thor 400 Agena 1171 | VAFB LC-75-1-2 | OPS 2268 | Reconnaissance | LEO | Failure | Loss of heat shield causes high thrust section temperatures. Control loss at T+113 seconds followed by propulsion system shutdown. |
| 1964-03-19 11:13:41 | Delta B | Thor 391 Delta 24 | CCAFS LC-17A | BE-A | Ionospheric | LEO | Failure | Third stage underperformed |
| 1964-03-24 12:15 | Thor DSV-2G | Thor 240 | CCAFS LC-17B | ASSET-2 | REV test | Suborbital | Failure | Atmospheric flight, second stage fired intermittently, destroyed by range safety |
| 1964-03-24 22:22:48 | TAT SLV-2A Agena-D | Thor 396 Agena 1175 | Arguello LC-1-1 | OPS 3467 | Reconnaissance | LEO | Failure | Agena power failure. No orbit. |
| 1964-04-21 18:50 | Thor DSV-2A Ablestar | Thor 379 Ablestar 014 | VAFB LC-75-1-1 | Transit 5BN-3 Transit 5E-4 | Navigation | LEO | Failure | |
| 1964-05-28 07:32 | Thor DSV-2J | Thor 227 | Johnston LE-2 | | ASAT test | Suborbital | Failure | |
| 1964-08-28 07:56:57 | Thor SLV-2 Agena-B | Thor 399 Agena 6201 TA-3 | VAFB LC-75-1-1 | Nimbus 1 | Weather | LEO | Partial failure | Second-stage cutoff early during second burn |
| 1964-10-04 03:45:00 | Delta C | Thor 392 Delta 26 | CCAFS LC-17A | Explorer 21 | Magnetospheric | HEO | Partial failure | Reached lower than planned orbit |
| 1965-01-19 05:03 | Thor MG-18 | Thor 224 | VAFB SLC-10W | DMSP-3B-F1 | Military weather satellite | planned: LEO / SSO | Partial failure | Maiden flight of the Thor-Burner series. Satellite failed to separate from the upper stage, but the satellite was able to operate for 6 months. |
| 1965-09-02 20:00 | Thor DM-21 Agena-D | Thor 401 Agena 1602 | VAFB LC-75-3-5 | MPRV | Upper atmosphere and space experiments | planned: MEO | Failure | High winds caused the vehicle to drift off course. RSO T+43 seconds. Debris fell on a trailer park. |
| 1966-01-08 04:48 | Thor Burner 1 | Thor 251 | VAFB SLC-10W | DMSP-3B-F5 | Military weather satellite | planned: LEO / SSO | Failure | FW-4S second-stage motor failed to ignite. |
| 1966-05-03 19:25 | TAT SLV-2A Agena-D | Thor 465 Agena 1625 | VAFB LC-75-3-5 | OPS 1508 (KH-4A #1032) | Reconnaissance | planned: LEO | Failure | Agena failed to separate from the Thor at staging. Vehicle fell into the Pacific Ocean. |
| 1967-05-09 21:50 | Thorad SLV-2G Agena-D | Thor 508 Agena 1634 | VAFB SLC-1E | KH-4A (S/N 1041)/SRV S/N 731 | Reconnaissance | planned: LEO | Partial failure | Rocket failed to cut off, resulting in incorrect, but usable orbit |
| 1968-05-18 08:23 | Thorad SLV-2G Agena-D | Thor 520 Agena 6221 | VAFB SLC-2E | Nimbus B/EGRS-10 | Weather Satellite / Geodesic research satellite | planned: LEO / SSO | Failure | Incorrectly installed yaw gyro led to loss of control. RSO T+101 seconds. |
| 1968-09-19 00:09 | Delta M | Thor 529 Delta 59 | CCAFS SLC-17A | Intelsat 3-1 | Communication Satellite | planned: GTO | Failure | Pitch gyroscope failure led to loss of control starting at T+20 seconds. RSO T+110 seconds. |
| 1969-07-26 02:06 | Delta M | Thor 547 Delta 71 | CCAFS SLC-17A | Intelsat 3-5 | Communication Satellite | planned: GTO | Partial failure | Stage 3 motor case ruptured, leaving spacecraft in unusable orbit |
| 1969-08-27 21:59 | Delta L | Thor 540 Delta 73 | CCAFS LC-17A | Pioneer E / TTS-3 | Interplanetary space research probe / Technology demonstration satellite | planned: Heliocentric | Failure | Defective valve in Stage 1 caused a hydraulic fluid leak and loss of engine gimbaling at T+220 seconds, making it impossible for the second stage to reach orbit. RSO T+480 seconds. |
| 1970-1979 |||||||||
| Date/Time (UTC) | Rocket | S/N | Launch Site | Payload | Function | Orbit | Outcome | Remarks |
| 1970-04-24 | Thor DSV-2J | Thor 225 | | Johnston LE-1 | Satellite Inspection test | Suborbital | Failure | Thor rocket collided with the satellite. |
| 1971-02-17 20:04 | Thorad SLV-2H Agena-D | Thor 537 Agena 1659 | VAFB SLC-3W | KH-4B (S/N 1113) | Reconnaissance | LEO | Failure | Improper pre-flight procedure caused frozen lubricant to form a plug that resulted in complete turbopump failure 18 seconds after liftoff. The booster lost thrust and impacted the ground not far from the launch complex. |
| 1971-10-21 11:32 | Delta N6 | Delta 86 Thor 572 | VAFB SLC-2E | ITOS-B | Weather Satellite | planned: LEO / SSO | Failure | 2nd stage oxidizer leak starting at T+20 seconds. The attitude control system ran out of propellant trying to correct the stage's flight path and the launch vehicle reentered the atmosphere and broke up above the Arctic Circle. |
| 1973-07-16 17:10 | Delta 300 | Delta 96 Thor 578 | VAFB SLC-2W | ITOS-E | Weather Satellite | planned: LEO / SSO | Failure | Hydraulic pump malfunction led to failure of the 2nd stage attitude control system. The booster and payload reentered the atmosphere and broke up. |
| 1974-01-19 01:38 | Delta 2313 | Delta 100 Thor 587 | CCAFS SLC-17B | Skynet-2A | Military communication satellite | planned: GTO | Failure | First flight of the Delta 2000 series. Stage 2 electronics package short circuited (induced by a piece of conductive contaminant shaken loose during launch), leading to loss of control. |
| 1976-02-19 07:52 | Thor Burner 2A | Thor 182 | VAFB SLC-10W | DMSP-5C-F3 | Military weather satellite | planned: LEO / SSO | Failure | Thor stage not loaded with enough kerosene fuel due to incorrect LR79 main engine data sheet entry. Satellite re-entered after one orbit. |
| 1977-04-20 10:15 | Delta 2914 | Delta 130 Thor 617 | CCAFS SLC-17B | ESA-GEOS-1 | Magnetosphere research satellite | planned: GTO | Partial failure | Premature separation of second and third stages led to failure of Stage 3 spin up. |
| 1977-09-13 23:21 | Delta 3914 | Delta 134 Thor 619 | CCAFS SLC-17A | OTS-1 | Experimental communication satellite | planned: GTO | Failure | Launch vehicle exploded at T+52 seconds due to a rupture of the SRM #1 casing. |
| 1979-02-06 08:46 | N-I | N-5 (F) | Tanegashima SLC-N | ECS-A (Ayame 1) | Experimental communication satellite | planned: GTO | Failure | Recontact between satellite and upper stage. |
| 1980-1989 |||||||||
| Date/Time (UTC) | Rocket | S/N | Launch Site | Payload | Function | Orbit | Outcome | Remarks |
| 1980-07-15 02:22 | Thor DSV-2U | Thor 304 | VAFB SLC-10W | DMSP-5D-F5 | Military weather satellite | planned: LEO / SSO | Failure | Final flight of the Long Tank Thor. Failure attributed to faulty connection between second and third stages, resulting in third stage not receiving electrical power. |
| 1986-05-03 22:18 | Delta 3914 | 178 | CCAFS LC-17A | GOES-G | Weather Satellite | planned: GTO | Failure | Electric failure in first stage caused the rocket to lose control and was destroyed 90 seconds into flight |
| 1990-1999 |||||||||
| Date / time (UTC) | Rocket Configuration | Launch site | Payload | Payload mass | Orbit | Customer | Outcome | Remarks |
| 5 August 1995 11:10 | Delta II 7925–9.5 | CCAFS, LC-17B | Koreasat 1 | 711 kg | GTO | KT Corporation | Partial failure | Communications satellite, One SRB failed to separate, retarding the booster's orbital velocity. Spacecraft eventually reached correct orbit but with substantially shortened operational life. |
| January 17, 1997 16:28 | Delta II 7925–9.5 | CCAFS LC-17A | GPS IIR-1 | 2,030 kg | Planned: MEO | US Air Force | Failure | Exploded 13 seconds after launch due to SRB failure. Navigation satellite |
| August 27, 1998 01:17 | Delta III 8930 | CCAFS SLC-17B | Galaxy 10 | 700 kg | GTO | PanAmSat / Intelsat | Failure | Maiden flight of Delta III, Destroyed by range safety after control problems and depletion of hydraulic fluid, Communications satellite |
| May 5, 1999 01:00 | Delta III 8930 | CCAFS SLC-17B | Orion 3 | 4,300 kg | GTO | Loral | Failure | Second stage engine failure. Payload placed into LEO, Communications satellite |
| Since 2000 |||||||||
| Date / time (UTC) | Rocket, Configuration | Launch site | Payload | Payload mass | Orbit | Customer | Launch outcome | Remarks |
| August 23, 2000 11:05 | Delta III 8930 | CCAFS SLC-17B | DM-F3 | 4383 kg | GTO | US Air Force | Partial failure | Reached lower than planned orbit, final flight of Delta III, Demosat |
| December 21, 2004 21:50 | Delta IV Heavy | CCAFS SLC-37B | DemoSat / 3CS-1 / 3CS-2 | >6020 kg | GSO (planned) | | Partial failure | Demonstration payload, Payloads did not reach correct orbits, First Delta IV Heavy launch |