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

space telescope A space telescope or 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-2 launch ...

dedicated to observing the sky in the

X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...

band. It was launched on 15 October 1974 from the

San Marco platform The Luigi Broglio Space Center (BSC) is an Italian-owned spaceport near Malindi, Kenya, named after its founder and Italian space pioneer Luigi Broglio. Developed in the 1960s through a partnership between the Sapienza University of Rome's Aero ...

in the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by t ...

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

Ariel programme Ariel was a British satellite research programme conducted between the early 1960s and 1980s. Six satellites were launched as part of the programme, starting with the first British satellite, Ariel 1, which was launched on 26 April 1962, and concl ...

Background

Ariel 5 was the fifth and penultimate satellite of the joint British and American

. 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 were ...

launch. The

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

(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 The Scout family of rockets were American launch vehicles designed to place small satellites into orbit around the Earth. The Scout multistage rocket was the first orbital launch vehicle to be entirely composed of solid fuel stages. It was also t ...

'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 Ariel 4, known pre-launch as UK 4, was a British ionospheric research satellite, which was operated by the Science and Engineering Research Council. It was launched 11 December 1971, aboard an American Scout rocket. Experiments were designed to mee ...

. 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's 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 (bps), 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 guppy (), also known as millionfish and rainbow fish, is one of the world's most widely distributed tropical fish and one of the most popular freshwater aquarium fish species. It is a member of the family Poeciliidae and, like almost all ...

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