Agena

Agena is an upper stage rocket developed by Lockheed Corporation for use with National Aeronautics and Space Administration (NASA) launch vehicles, including the Atlas rocket and Titan IIIB. The Agena stage was designed to provide a reliable and efficient way to place satellites and other spacecraft into Earth orbit and beyond, working in conjunction with NASA's Jet Propulsion Laboratory and United States Air Force Space Command. Agena played a critical role in numerous space missions, including the Ranger program, Lunar Orbiter program, and Corona program, often launching from Vandenberg Air Force Base and Cape Canaveral Air Force Station.

Introduction

The Agena upper stage was first developed in the late 1950s by Lockheed Missiles & Space Company, with the first launch occurring in 1959, carrying a Discoverer satellite into low Earth orbit. The Agena stage was designed to be highly versatile, with the ability to launch a wide range of spacecraft, from small reconnaissance satellites like Corona and KH-7 Gambit to larger interplanetary spacecraft like Mariner 2 and Ranger 4, which were managed by NASA's Marshall Space Flight Center and NASA's Goddard Space Flight Center. Agena was also used in conjunction with other launch vehicles, including the Thor rocket and Delta rocket, to launch satellites like Tiros-1 and Echo 1A into Earth orbit, with support from European Space Agency and Canadian Space Agency.

Design and Development

The Agena upper stage was designed to be a self-contained rocket stage, with its own guidance system, propulsion system, and power source, developed in collaboration with MIT Instrumentation Laboratory and Stanford Research Institute. The Agena stage used a Bell Aerosystems rocket engine, which provided a high level of specific impulse and thrust-to-weight ratio, similar to the Rocketdyne F-1 engine used in the Saturn V rocket. The Agena stage also featured a highly advanced guidance system, which used a combination of inertial measurement units and star trackers to provide highly accurate navigation and control, developed with the help of Draper Laboratory and Charles Stark Draper. The Agena stage was designed to be highly reliable, with a success rate of over 90%, thanks to the contributions of NASA's Langley Research Center and NASA's Ames Research Center.

Operational History

The Agena upper stage was used in a wide range of space missions, including the Gemini program, which used the Agena stage as a target vehicle for space rendezvous and docking tests, with NASA's Johnson Space Center playing a key role. The Agena stage was also used to launch numerous satellites into Earth orbit, including the Intelsat 1 and Telstar 1 communications satellites, which were operated by Intelsat and AT&T, with support from Federal Communications Commission and European Telecommunications Satellite Organization. In addition, the Agena stage was used to launch several interplanetary spacecraft, including the Mariner 3 and Mariner 4 Mars flyby missions, which were managed by NASA's Jet Propulsion Laboratory and California Institute of Technology.

Variants

There were several variants of the Agena upper stage, including the Agena A, Agena B, and Agena D, each with its own unique capabilities and characteristics, developed in partnership with Boeing, North American Aviation, and Douglas Aircraft Company. The Agena A was the first variant to be developed, and was used in the early Corona program satellite launches, with CIA and National Reconnaissance Office involvement. The Agena B was a more advanced variant, with a higher thrust-to-weight ratio and specific impulse, used in the Ranger program and Lunar Orbiter program, with support from United States Geological Survey and National Oceanic and Atmospheric Administration. The Agena D was the most advanced variant, with a highly advanced guidance system and propulsion system, used in the Gemini program and Apollo program, with contributions from MIT, Stanford University, and California Institute of Technology.

Specifications

The Agena upper stage had a length of 7.9 meters (25.9 feet) and a diameter of 1.5 meters (4.9 feet), with a mass of approximately 6,800 kilograms (15,000 pounds), similar to the Saturn IB rocket and Delta IV rocket. The Agena stage used a Bell Aerosystems rocket engine, which provided a thrust of 71 kilonewtons (16,000 pounds-force) and a specific impulse of 316 seconds, comparable to the Rocketdyne H-1 engine used in the Saturn I rocket. The Agena stage had a propellant capacity of approximately 13,600 kilograms (30,000 pounds), with a burn time of up to 265 seconds, allowing it to launch spacecraft like Pioneer 10 and Voyager 1 into interplanetary trajectories, with support from NASA's Deep Space Network and European Space Agency's European Space Operations Centre.