Thor-Agena was a series of orbital launch vehicle

Launch vehicle

In spaceflight, a launch vehicle or carrier rocket is a rocket used to carry a payload from the Earth's surface into outer space. A launch system includes the launch vehicle, the launch pad and other infrastructure....

s. The rocket

Rocket

A rocket is a missile, spacecraft, aircraft or other vehicle which obtains thrust from a rocket engine. In all rockets, the exhaust is formed entirely from propellants carried within the rocket before use. Rocket engines work by action and reaction...

s used Thor first stage

Multistage rocket

A multistage rocket is a rocket that usestwo or more stages, each of which contains its own engines and propellant. A tandem or serial stage is mounted on top of another stage; a parallel stage is attached alongside another stage. The result is effectively two or more rockets stacked on top of or...

s and Agena

RM-81 Agena

The RM-81 Agena was an American rocket upper stage and satellite support bus which was developed by Lockheed initially for the canceled WS-117L reconnaissance satellite program...

 second stages. They are thus cousins of the more famous Thor-Deltas, which founded the Delta rocket family. The first attempted launch of a Thor-Agena was in January 1959. The first successful launch was on February 28, 1959, launching Discoverer-1

Corona (satellite)

The Corona program was a series of American strategic reconnaissance satellites produced and operated by the Central Intelligence Agency Directorate of Science & Technology with substantial assistance from the U.S. Air Force...

.

Uses

Among other uses, the clandestine Corona

Corona (satellite)

The Corona program was a series of American strategic reconnaissance satellites produced and operated by the Central Intelligence Agency Directorate of Science & Technology with substantial assistance from the U.S. Air Force...

 program used Thor-Agenas from June 1959 until January 1968 to launch US

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 military reconnaissance satellite

Spy satellite

A spy satellite is an Earth observation satellite or communications satellite deployed for military or intelligence applications....

s operated by the CIA

Central Intelligence Agency

The Central Intelligence Agency is a civilian intelligence agency of the United States government. It is an executive agency and reports directly to the Director of National Intelligence, responsible for providing national security intelligence assessment to senior United States policymakers...

. In 1962, for example, Thor-Agena launch vehicles were used in 24 launch attempts now known to have been part of satellite surveillance programs.

Also, Alouette 1

Alouette 1

Alouette 1 was Canada's first satellite, and the first satellite constructed by a country other than the USSR or the United States. Occasionally, Alouette 1 is misrepresented as the third satellite successfully put in orbit, rather than being from the third country to have one of its own in space,...

, Canada's first satellite, was launched on a Thor-Agena-B.

Versions

Thor-Agena-A

• 16 launches between 21 Jan 1959 and 13 Sep 1960
• The Discoverer 14
  Discoverer 14
  Discoverer 14 was a spy satellite used in the Corona program managed by DARPA and the United States Air Force. On 19 August 1960, usable photographic film images taken by the satellite were recovered by a C-119 recovery aircraft...
  
   satellite used in the Corona
  Corona (satellite)
  The Corona program was a series of American strategic reconnaissance satellites produced and operated by the Central Intelligence Agency Directorate of Science & Technology with substantial assistance from the U.S. Air Force...
  
   spy satellite program was launched by a Thor-Agena-A. On 1960-08-19 usable photographic film from the satellite was recovered by a C-119
  C-119 Flying Boxcar
  The Fairchild C-119 Flying Boxcar was an American military transport aircraft developed from the World War II-era Fairchild C-82 Packet, designed to carry cargo, personnel, litter patients, and mechanized equipment, and to drop cargo and troops by parachute...
  
   recovery aircraft. This was the first successful recovery of film from an orbiting satellite and the first mid-air recovery
  Mid-air retrieval
  Mid-air retrieval is a technique used in atmospheric reentry when the reentering vehicle is incapable of a satisfactory unassisted landing. The vehicle is slowed by means of parachutes, and then a specially-equipped aircraft matches the vehicle's trajectory and catches it in mid-air.This is a risky...
  
  of an object returning from Earth orbit.

Thor-Agena-B

• First successful launch: Nov 12, 1960 with Discoverer 17
• Last launch: May 15, 1966 with Nimbus 2

Thor-Agena-D

• First launch: Jun 28, 1962
• Last launch: Jan 17, 1968