Thor-Delta

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 to LEO	270 kg
Launch history
Status	Retired
Launch sites	Cape Canaveral, LC-17
Total launches	12
Success(es)	11
Failure(s)	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
[edit on Wikidata]

The Thor-Delta, also known as Delta DM-19 or just Delta was an early American expendable launch system used for 12 orbital launches in the early 1960s. A derivative of the Thor-Able, it was a member of the Thor family of rockets, and the first member of the Delta family.^[1]

The first stage was a Thor missile in the DM-19 configuration (DM-18A / MB-3-I engine). The second stage was the Delta (AJ-10-142 engine), which had been derived from the earlier Able stage. An Altair solid rocket motor (X-248A-7) was used as a third stage.^[2][3]

The basic design of the original Vanguard upper stages, featuring a pressure-fed nitric acid/UDMH, regeneratively cooled engine, was kept in place, but with an improved AJ10-118 engine. More significantly, the Delta stage featured cold 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, the Delta II, remained in service until 2018.