OPS 0855, also designated OV4-3, was an American boilerplate

Manned Orbiting Laboratory The Manned Orbiting Laboratory (MOL) was part of the United States Air Force (USAF) human spaceflight program in the 1960s. The project was developed from early USAF concepts of crewed space stations as reconnaissance satellites, and was a su ...

spacecraft launched in 1966. It was flown to demonstrate the launch configuration for future MOL missions. A number of research payloads, designated Manifold, were carried on board, which were intended to operate for 75 days. However, the spacecraft ceased operations after just 30 days. It was built from a decommissioned

HGM-25A Titan I The Martin Marietta SM-68A/HGM-25A Titan I was the United States' first multistage intercontinental ballistic missile (ICBM), in use from 1959 until 1962. Though the SM-68A was operational for only three years, it spawned numerous follow-on mo ...

first stage oxidizer tank, bolted to a

Transtage Transtage, given the United States Air Force designation SSB-10A, was an American upper stage used on Titan III rockets, developed by Martin Marietta and Aerojet. History Transtage was developed in anticipation of a requirement to launch milita ...

. It was part of the MOL and Orbiting Vehicle projects. The Manifold experimental package consisted of two

micrometeoroid A micrometeoroid is a tiny meteoroid: a small particle of rock in space, usually weighing less than a gram. A micrometeorite is such a particle that survives passage through Earth's atmosphere and reaches Earth's surface. The term "micrometeor ...

detection payloads, a transmitter beacon designated ORBIS-Low, a cell growth experiment, a prototype

hydrogen fuel cell A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen fuel, hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most bat ...

, a thermal control experiment, a propellent transfer and monitoring system to investigate

fluid dynamics In physics and engineering, fluid dynamics is a subdiscipline of fluid mechanics that describes the flow of fluids— liquids and gases. It has several subdisciplines, including ''aerodynamics'' (the study of air and other gases in motion) a ...

zero gravity Weightlessness is the complete or near-complete absence of the sensation of weight. It is also termed zero gravity, zero G-force, or zero-G. Weight is a measurement of the force on an object at rest in a relatively strong gravitational f ...

, a prototype

attitude control system Spacecraft attitude control is the process of controlling the orientation of a spacecraft (vehicle/satellite) with respect to an inertial frame of reference or another entity such as the celestial sphere, certain fields, and nearby objects, et ...

, an experiment to investigate the reflection of light in space, and an experiment into heat transfer. The spacecraft was painted to allow it to be used as a target for an optical tracking and observation experiment from the ground. OPS 0855 was the primary payload of

Titan IIIC The Titan IIIC was an expendable launch system used by the United States Air Force from 1965 until 1982. It was the first Titan booster to feature large solid rocket motors and was planned to be used as a launcher for the Dyna-Soar, though the ...

3C-9, The

Gemini B The Manned Orbiting Laboratory (MOL) was part of the United States Air Force (USAF) human spaceflight program in the 1960s. The project was developed from early USAF concepts of crewed space stations as reconnaissance satellites, and was a succ ...

prototype capsule, known as Gemini SC-2, was flown on the same rocket, and was released onto a

suborbital A sub-orbital spaceflight is a spaceflight in which the spacecraft reaches outer space, but its trajectory intersects the atmosphere or surface of the gravitating body from which it was launched, so that it will not complete one orbital ...

trajectory during launch. The adaptor connecting the

Gemini spacecraft Project Gemini () was NASA's second human spaceflight program. Conducted between projects Mercury and Apollo, Gemini started in 1961 and concluded in 1966. The Gemini spacecraft carried a two-astronaut crew. Ten Gemini crews and 16 individual ...

to OPS 0855 contained three additional spacecraft, two OV4-1 satellites, and OV1-6. These were released into

low Earth orbit A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never m ...

. OPS 0855 entered an orbit with an

apogee An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any el ...

of , a perigee of , and 32.82 degrees of

inclination Orbital inclination measures the tilt of an object's orbit around a celestial body. It is expressed as the angle between a reference plane and the orbital plane or axis of direction of the orbiting object. For a satellite orbiting the Ea ...

. It received the COSPAR

International Designator The International Designator, also known as COSPAR ID, is an international identifier assigned to artificial objects in space. It consists of the launch year, a three-digit incrementing launch number of that year and up to a three-letter code repr ...

1966-099A, and remained in orbit until its decay on 9 January 1967. No further MOL missions were flown following the cancellation of the project in June 1969.

References

Spacecraft which reentered in 1967 Spacecraft launched in 1966 Military space program of the United States {{US-spacecraft-stub