OPS 3762, also known as FTV-2355, was an American

reconnaissance satellite A reconnaissance satellite or intelligence satellite (commonly, although unofficially, referred to as a spy satellite) is an Earth observation satellite or communications satellite deployed for military or intelligence applications. The ...

which was launched in 1964. It was the first

radar imaging Radar is a system that uses radio waves to determine the distance (''ranging''), direction (geometry), direction (azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to det ...

satellite to be launched, and the only

Quill A quill is a writing tool made from a moulted flight feather (preferably a primary wing-feather) of a large bird. Quills were used for writing with ink before the invention of the dip pen/metal-Nib (pen), nibbed pen, the fountain pen, and, event ...

spacecraft to fly. Its mission was to demonstrate radar imaging techniques for future missions. However, the programme was cancelled before any more satellites were launched. OPS 3762 was successfully launched aboard a Thrust Augmented Thor SLV-2A Agena-D carrier rocket, flying from Launch Complex 75-1-1 at the

Vandenberg Air Force Base Vandenberg may refer to: * Vandenberg (surname), including a list of people with the name * USNS ''General Hoyt S. Vandenberg'' (T-AGM-10), transport ship in the United States Navy, sank as an artificial reef in Key West, Florida * Vandenberg S ...

. The launch, which was the last orbital launch of the year, occurred at 19:08:56 UTC on 21 December 1964, and successfully placed the spacecraft into the

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 ...

in which it conducted its mission. Owing to concerns that using radar over the

Soviet Union The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

may have been seen as provocative, OPS 3762 conducted imaging tests over the

Northwestern United States The Northwestern United States, also known as the American Northwest or simply the Northwest, is an informal geographic region of the United States. The region consistently includes the states of Oregon, Washington, Idaho, Montana and Wyoming ...

instead. OPS 3762 was a spacecraft, based on the Agena-D which also served as the upper stage of its carrier rocket. It operated for four days. Its orbit had a

perigee 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 , 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 , 70 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 ...

, and an

orbital period The orbital period (also revolution period) is the amount of time a given astronomical object takes to complete one orbit around another object. In astronomy, it usually applies to planets or asteroids orbiting the Sun, moons orbiting planets ...

of 88.8 minutes. Its

side looking airborne radar Side-looking airborne radar (SLAR) is an aircraft, or satellite-mounted imaging radar pointing perpendicular to the direction of flight (hence ''side-looking''). A Squint (antenna), squinted (nonperpendicular) mode is also possible. SLAR can be ...

produced images, which were returned in a KH-4 film capsule at the end of the mission. OPS 3762 itself remained in orbit until 11 January 1965, when its orbit decayed and it reentered the atmosphere. OPS 3762 completed its mission successfully.

References

Spacecraft launched in 1964 Space synthetic aperture radar {{US-spacecraft-stub

See also

References