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 succ ...

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 mode ...

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 Orbiting Vehicle or OV, originally designated SATAR (SATellite - Atmospheric Research), comprised five different series of standardized American satellites operated by the US Air Force, launched between 1965 and 1971. Forty seven satellites w ...

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 "micrometeoro ...

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) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requ ...

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

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

zero gravity Weightlessness is the complete or near-complete absence of the sensation of weight, i.e., zero apparent weight. It is also termed zero g-force, or zero-g (named after the g-force) or, incorrectly, zero gravity. Weight is a measurement of the fo ...

, a prototype

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

, 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 (rocket family), Titan booster to feature large solid rocket motors and was planned to be used as a launcher for the D ...

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 Gemini SC-2 (Spacecraft No. 2) was the second NASA Project Gemini full-up reentry capsule built. This McDonnell Aircraft, McDonnell Gemini capsule was the first space capsule to be reused, flying twice in suborbital flights. SC-2 flew on Gemini 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 surface of the gravitating body from which it was launched. Hence, it will not complete one orbital revolution, will no ...

trajectory during launch. The adaptor connecting the

Gemini spacecraft Project Gemini () was the second United States human spaceflight program to fly. Conducted after the first American crewed space program, Project Mercury, while the Apollo program was still in early development, Gemini was conceived in 1961 and ...

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 geocentric orbit, orbit around Earth with a orbital period, period of 128 minutes or less (making at least 11.25 orbits per day) and an orbital eccentricity, eccentricity less than 0.25. Most of the artificial object ...

. 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. The line of apsides (also called apse line, or major axis of the orbit) is the line connecting the two extreme values. Apsides perta ...

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 Eart ...

. It received the COSPAR International Designator 1966-099A, and remained in orbit until its

decay Decay may refer to: Science and technology * Bit decay, in computing * Decay time (fall time), in electronics * Distance decay, in geography * Software decay, in computing Biology * Decomposition of organic matter * Mitochondrial decay, in g ...

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