Ariel 5 (or UK 5) was a joint British and American

space telescope A space telescope (also known as space observatory) is a telescope in outer space used to observe astronomical objects. Suggested by Lyman Spitzer in 1946, the first operational telescopes were the American Orbiting Astronomical Observatory, OAO ...

dedicated to observing the sky in the

X-ray An X-ray (also known in many languages as Röntgen radiation) is a form of high-energy electromagnetic radiation with a wavelength shorter than those of ultraviolet rays and longer than those of gamma rays. Roughly, X-rays have a wavelength ran ...

band. It was launched on 15 October 1974 from the

San Marco platform The Luigi Broglio Malindi Space Center (LBMSC) located near Malindi, Kenya, is an Italian Space Agency (ASI) Spaceport. It was named after its founder and Italian space pioneer Luigi Broglio. Developed in the 1960s through a partnership betwe ...

in the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...

and operated until 1980. It was the penultimate satellite to be launched as part of the Ariel programme.

Background

Ariel 5 was the fifth and penultimate satellite of the joint British and American Ariel programme. It was the third satellite in the series built entirely in the UK. It was named UK 5 before launch and renamed to Ariel 5 after the successful launch. Plans for Ariel 5 were first discussed between the UK and US in May 1967 at the

Ariel 3 Ariel 3 (UK 3 or United Kingdom Research Satellite 3) was a satellite in the Ariel programme, a satellite partnership between the US and UK. Three of the onboard experiments continued research from the first two missions and two experiments wer ...

launch. The

Science Research Council The Science and Engineering Research Council (SERC) and its predecessor the Science Research Council (SRC) were the United Kingdom, UK agencies in charge of publicly funded scientific and engineering research activities, including astronomy, biote ...

(SRC) advertised a request for proposal for experiments in June. Experiments were formally proposed to NASA in July 1968.

Satellite design

Development

Marconi Space and Defence Systems (MSDS) in Portsmouth was selected as the prime contractor in 1969. SRC had them select MSDS Frimley for the attitude control system (ACS) and MSDS Stanmore for the core stores. A study was performed to see if the Scout rocket's heat shield could be enlarged to accommodate larger experiments for this mission. A larger heat shield was designed which allowed for a US experiment and five British experiments.

Operation

Ariel 5 was spin-stabilized. The satellite improved on the attitude control of Ariel 4. It used liquid propane that was expanded through a reducing valve and heated with the bulk tank temperature. Power was derived from solar cells that were mounted to 7/8 of the circumference of the spacecraft. It was stored in a 3.0 Ah Ni-Cd battery.

Sensors

The all-sky monitor (ASM) was two one-dimensional pinhole cameras scanned most of the sky every spacecraft revolution. The angular resolution was 10° × 10°, with an effective area of , and a bandpass of 3–6 keV. The ASM was designed to fit a resource budget of , 1 bit per second, and 1 W. The sky survey instrument (SSI) had an angular resolution of 0.75 × 10.6°, with an effective area of , and a bandpass of 2–20 keV.

Mission

Launch

Launch operations took six weeks, starting from the time the

Guppy The Greater Underwater Propulsion Power Program (GUPPY) was initiated by the United States Navy after World War II to improve the submerged speed, maneuverability, and endurance of its submarines. (The "Y" in the acronym was added for pronouncea ...

took off from Thorney Island. The satellite was launched on 15 October 1974 from the

in the

off the coast of Kenya.

Operations

The satellite was controlled via a mission control centre in Appleton Lab. It spun at over 10 revolutions/minute. Ariel 5 operated until 1980.

Background

Satellite design

Development

Operation

Sensors

Mission

Launch

Operations

Results

Notes

References

Further reading