Thor-Ablestar

The launch of a Thor-Ablestar 2 with a Transit satellite.
Function	Orbital carrier rocket
Manufacturer	Douglas / Aerojet
Country of origin	United States
Size
Height	29 metres (95 ft)
Diameter	2.44 metres (8 ft 0 in)
Mass	53,000 kilograms (117,000 lb)
Stages	2
Capacity
Payload to 1100km LEO
Mass	150 kilograms (330 lb)
Associated rockets
Family	Thor
Comparable	Delta
Launch history
Launch sites	LC-17, Canaveral LC-75-1, Arguello
Total launches	19
Success(es)	12
Failure(s)	5
Partial failure(s)	2
First flight	13 April 1960
Last flight	13 August 1965
First stage – Thor
Powered by	1 MB-3-1
Maximum thrust	760.64 kilonewtons (171,000 lbf)
Specific impulse	285 sec
Burn time	164 seconds
Propellant	RP-1/LOX
Second stage – Ablestar
Powered by	1 AJ-10
Maximum thrust	36.02 kilonewtons (8,100 lbf)
Specific impulse	280 sec
Burn time	296 seconds
Propellant	HNO3/UDMH
[edit on Wikidata]

The Thor-Ablestar, or Thor-Able-Star, also known as Thor-Epsilon ^[1] was an early American expendable launch system consisting of a PGM-17 Thor missile, with an Ablestar upper stage. It was a member of the Thor family of rockets, and was derived from the Thor-Able.

The Ablestar second stage was an enlarged version of the Able, which gave the Thor-Ablestar a greater payload capacity compared to the Thor-Able. It also incorporated restart capabilities, allowing a multiple-burn trajectory to be flown, further increasing payload, or allowing the rocket to reach different orbits. It was the first rocket to be developed with such a capability and development of the stage took a mere eight months.^[2]

Two versions were built; the Thor-Ablestar 1, with a DM-21 Thor and an AJ-10-104 second stage engine, and the Thor-Ablestar 2, which had a DSV-2A Thor first stage, and an uprated AJ-10-104D engine on the second stage.^[1] Thor-Ablestar 1 launches occurred from LC-17 at Cape Canaveral, and Thor-Ablestar 2 rockets were launched from LC-75-1 at Vandenberg Space Force Base (now designated SLC-2).