Ariel 4, also known as UK 4, was a British ionospheric

Ionosphere

The ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere...

 research satellite

Satellite

In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....

, which was operated by the Science and Engineering Research Council

Science and Engineering Research Council

The Science and Engineering Research Council used to be the UK agency in charge of publicly funded scientific and engineering research activities including astronomy, biotechnology and biological sciences, space research and particle physics...

. It was built by the British Aircraft Corporation

British Aircraft Corporation

The British Aircraft Corporation was a British aircraft manufacturer formed from the government-pressured merger of English Electric Aviation Ltd., Vickers-Armstrongs , the Bristol Aeroplane Company and Hunting Aircraft in 1960. Bristol, English Electric and Vickers became "parents" of BAC with...

, and had a mass at launch of 100 kilograms (220.5 lb). It was launched in 1971, aboard an American rocket.

The launch of Ariel 4 occurred at 20:47:01 GMT on 11 December 1971, from Space Launch Complex 5

Vandenberg AFB Space Launch Complex 5

Space Launch Complex 5 was a launch pad at Vandenberg Air Force Base in California, United States. It was previously part of the Point Arguello Naval Air Station, during which time it was designated Launch Complex D or LC-D. Constructed in 1961, it was used by 69 Scout rockets between 1962 and 1994...

 at the Vandenberg Air Force Base

Vandenberg Air Force Base

Vandenberg Air Force Base is a United States Air Force Base, located approximately northwest of Lompoc, California. It is under the jurisdiction of the 30th Space Wing, Air Force Space Command ....

. It was conducted by the United States

United States

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

 National Aeronautics and Space Administration

NASA

The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

, using a Scout B-1 rocket. Ariel 4 was placed into a Low Earth orbit

Low Earth orbit

A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...

, with a perigee of 473 kilometres (293.9 mi), an apogee of 590 kilometres (366.6 mi), 82.9 degrees of inclination

Inclination

Inclination in general is the angle between a reference plane and another plane or axis of direction.-Orbits:The inclination is one of the six orbital parameters describing the shape and orientation of a celestial orbit...

 and an orbital period

Orbital period

The orbital period is the time taken for a given object to make one complete orbit about another object.When mentioned without further qualification in astronomy this refers to the sidereal period of an astronomical object, which is calculated with respect to the stars.There are several kinds of...

of 95.3 minutes. It decayed from orbit on 12 December 1978.