Thor 320 Delta 9 rocket with UK first satellite Ariel 1, 26 April 1962 | |
| Function | Expendable launch system |
|---|---|
| Country of origin | United States |
| Capacity | |
| Payload toLEO | 270 kg |
| Launch history | |
| Status | Retired |
| Launch sites | Cape Canaveral,LC-17 |
| Total launches | 12 |
| Success(es) | 11 |
| Failure | 1 |
| First flight | 13 May 1960 |
| Last flight | 18 September 1962 |
| First stage - Thor DM-19 | |
| Engines | DM-18A / MB-3-I |
| Second stage Delta | |
| Engines | AJ-10-142 |
| Third stage | |
| Engines | X-248A-7 |
TheThor-Delta, also known asDelta DM-19 or justDelta was an early Americanexpendable launch system used for 12orbital launches in the early 1960s. A derivative of theThor-Able, it was a member of theThor family of rockets, and the first member of theDelta family.[1]
The first stage was aThor missile in the DM-19 configuration (DM-18A / MB-3-I engine). The second stage was theDelta (AJ-10-142 engine), which had been derived from the earlierAble stage. AnAltairsolid rocket motor (X-248A-7) was used as a third stage.[2][3]
The basic design of the originalVanguard upper stages, featuring apressure-fed nitric acid/UDMH, regeneratively cooled engine, was kept in place, but with an improvedAJ10-118 engine. More significantly, the Delta stage featuredcold gas attitude control jets allowing it to be stabilized in orbit for restart and more precise burns.
The Thor-Delta was the first rocket to use the combination of a Thor missile and a Delta upper stage. This configuration was reused for many later rockets, and a derivative, theDelta II, remained in service until 2018.
The Thor-Delta launched a number of significant payloads, including the firstcommunications satellite,Echo 1A; the first British satellite,Ariel 1; and the first active direct-relay communications satellite,Telstar 1. All 12 launches occurred fromCape Canaveral Air Force StationLaunch Complex 17. The launch of Telstar 1 used pad B, while all other launches were from pad A. All launches were successful except the maiden flight, which failed to placeEcho 1 into orbit due to a problem with the second stage.[3]
| Date/time (UTC) | Rocket | S/N | Launch site | Payload | Function | Orbit | Outcome | Remarks |
|---|---|---|---|---|---|---|---|---|
| 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 |
| 1960-08-12 09:39:43 | Thor DM-19 Delta | Thor 270 Delta 2 | CCAFS LC-17A | Echo 1A | Communications | MEO | Success | |
| 1960-11-23 11:13:03 | Thor DM-19 Delta | Thor 245 Delta 3 | CCAFS LC-17A | TIROS-2 | Weather | SSO | Success | |
| 1961-03-25 15:17:04 | Thor DM-19 Delta | Thor 295 Delta 4 | CCAFS LC-17A | Explorer 10 | Magnetospheric | HEO | Success | |
| 1961-07-12 10:25:06 | Thor DM-19 Delta | Thor 286 Delta 5 | CCAFS LC-17A | TIROS-3 | Weather | SSO | Success | |
| 1961-08-16 03:21:05 | Thor DM-19 Delta | Thor 312 Delta 6 | CCAFS LC-17A | Explorer 12 | Magnetospheric | HEO | Success | |
| 1962-02-08 12:43:45 | Thor DM-19 Delta | Thor 317 Delta 7 | CCAFS LC-17A | TIROS-4 | Weather | SSO | Success | |
| 1962-03-07 16:06:18 | Thor DM-19 Delta | Thor 301 Delta 8 | CCAFS LC-17A | OSO-1 | Solar | LEO | Success | |
| 1962-04-26 18:00:16 | Thor DM-19 Delta | Thor 320 Delta 9 | CCAFS LC-17A | Ariel 1 | Ionospheric | LEO | Success | |
| 1962-06-19 12:19:01 | Thor DM-19 Delta | Thor 321 Delta 10 | CCAFS LC-17A | TIROS-5 | Weather | SSO | Success | |
| 1962-07-10 08:35:05 | Thor DM-19 Delta | Thor 316 Delta 11 | CCAFS LC-17B | Telstar 1 | Communication | MEO | Success | |
| 1962-09-18 08:53:08 | Thor DM-19 Delta | Thor 318 Delta 12 | CCAFS LC-17A | TIROS-6 | Weather | SSO | Success | Final flight of Thor-Delta |