Orba, also known as X-2, was intended to be the first 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....

 launched by a British

United Kingdom

The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 rocket. It was launched at 00:34 GMT on 2 September 1970, atop a Black Arrow

Black Arrow

Black Arrow, officially capitalised BLACK ARROW, was a British satellite carrier rocket. Developed during the 1960s, it was used for four launches between 1969 and 1971...

 rocket from Launch Area 5B

Woomera Launch Area 5

Launch Area 5 at the Woomera Prohibited Area was a rocket launch site which supported a number of British experimental launches, including Britain's first, and as of 2011 only, satellite launch. It consisted of three separate launch pads, which supported 22 Black Knight sounding rocket launches,...

 at Woomera

Woomera Test Range

The RAAF Woomera Test Range is a weapons testing range operated by the Royal Australian Air Force Aerospace Operational Support Group...

, but failed to reach orbit after the second stage of the carrier rocket shut down 13 seconds early. Orba was built from spare parts due to funding restrictions, and was to have been used to measure upper atmosphere density by monitoring the decay

Orbital decay

Orbital decay is the process of prolonged reduction in the altitude of a satellite's orbit.This can be due to drag produced by an atmosphere due to frequent collisions between the satellite and surrounding air molecules. The drag experienced by the object is larger in the case of increased solar...

of its orbit.