Thor-Ablestar
Encyclopedia
The Thor-Ablestar, or Thor Able-Star, also known as Thor-Epsilon was an American
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 expendable launch system
Expendable launch system
An expendable launch system is a launch system that uses an expendable launch vehicle to carry a payload into space. The vehicles used in expendable launch systems are designed to be used only once , and their components are not recovered for re-use after launch...

 consisting of a PGM-17 Thor
PGM-17 Thor
Thor was the first operational ballistic missile of the U.S. Air Force . Named after the Norse god of thunder, it was deployed in the United Kingdom between 1959 and September 1963 as an intermediate range ballistic missile with thermonuclear warheads. Thor was in height and in diameter. It was...

 missile, with an Ablestar upper stage. It was a member of the Thor family of rockets, and was derived from the Thor-Able
Thor-Able
The Thor-Able was an American expendable launch system and sounding rocket used for a series of re-entry vehicle tests and satellite launches between 1958 and 1960. It was a two stage rocket, consisting of a Thor IRBM as a first stage, and a Vanguard-derived Able second stage. On some flights, an...

.

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.

Nineteen Thor-Ablestars were launched, of which four failed, and a fifth resulted in a partial failure, as only one of two payloads separated from the upper stage. Two versions were built; the Thor-Ablestar 1, with a DM-21 Thor, and an AJ-10-104
AJ-10
The AJ-10 or AJ10 is a hypergolic rocket engine. It has been used to propel the upper stages of several carrier rockets, including the Delta II and Titan III. It will also be used as the main engine of the Orion Crew Exploration Vehicle for NASA's Project Constellation.It was first used in the Able...

 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. Thor-Ablestar 1 launches occurred from LC-17
Cape Canaveral Air Force Station Launch Complex 17
Cape Canaveral Air Force Station Space Launch Complex 17 , previously designated Launch Complex 17 , was a launch site at Cape Canaveral Air Force Station, Florida used for Thor and Delta rocket launches between 1958 and 2011....

 at Cape Canaveral
Cape Canaveral Air Force Station
Cape Canaveral Air Force Station is an installation of the United States Air Force Space Command's 45th Space Wing, headquartered at nearby Patrick Air Force Base. Located on Cape Canaveral in the state of Florida, CCAFS is the primary launch head of America's Eastern Range with four launch pads...

, and Thor-Ablestar 2 rockets were launched from LC-75-1 at Point Arguello
Point Arguello
Point Arguello is a headland used as a launch site by the United States Navy. Point Arguello was first used in 1959 for the launch of military and sounding rockets. It was transferred to the United States Air Force in 1964, at which time it became part of Vandenberg Air Force Base.There were 6...

m, which has since become part of Vandenberg Air Force Base
Vandenberg Air Force Base
Vandenberg Air Force Base is a United States Air Force Base, located approximately northwest of Lompoc, California. It is under the jurisdiction of the 30th Space Wing, Air Force Space Command ....

 and is now designated SLC-2
Vandenberg AFB Space Launch Complex 2
Space Launch Complex 2 is an active rocket launch site at Vandenberg Air Force Base, in California, USA. It consists of two launch pads. The East pad , which has been demolished, was used for Delta, Thor-Agena and Thorad launches between 1966 and 1972...

.
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