:Ariel 5

{{Infobox spaceflight

| name = Ariel 5

| names_list = Ariel5, PL-732B, UK 5, United Kingdom 5

| image = Ariel-5.jpg

| image_caption =

| image_alt =

| image_size =

| mission_type = Astronomy

| operator = SERC / NASA

| COSPAR_ID = 1974-077A

| SATCAT = 7471

| website =

| mission_duration =

| distance_travelled =

| orbits_completed =

| spacecraft =

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| spacecraft_bus =

| manufacturer = Goddard Space Flight Center

| launch_mass = {{convert|130.5|kg|lb|abbr=on}}

| BOL_mass =

| dry_mass =

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| dimensions =

| power =

| launch_date = {{start-date|15 October 1974, 07:47:00|timezone=yes}} UTC

| launch_rocket = Scout B-1

| launch_site = San Marco

| launch_contractor =

| entered_service =

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| last_contact =

| decay_date = 14 March 1980

| orbit_reference =

| orbit_regime =

| orbit_semimajor =

| orbit_eccentricity = 0.00325

| orbit_periapsis = {{convert|512|km|mi|abbr=on}}

| orbit_apoapsis = {{convert|557|km|mi|abbr=on}}

| orbit_inclination = 2.9 degrees

| orbit_period = 95.3 minutes

| orbit_RAAN =

| orbit_arg_periapsis =

| orbit_mean_anomaly =

| orbit_mean_motion =

| orbit_repeat =

| orbit_epoch = 14 October 1974, 23:00:00 UTC{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/displayTrajectory.action?id=1974-077A|title=Ariel 5 Trajectory Details|website=NASA Space Science Data Coordinated Archive|access-date=8 March 2020}}

| apsis = gee

| instrument_type =

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| instruments = {{unbulleted list|Rotation Modulation Collimator|2- to 10-KeV Sky Survey Instrument|High-Resolution Source Spectra|Bragg Crystal Spectrometer|High-Energy Cosmic X-Ray Spectra|All-Sky Monitor}}

| programme = Ariel

| previous_mission = Ariel 4

| next_mission = Ariel 6

}}

Ariel 5 (or UK 5) was a joint British and American space telescope dedicated to observing the sky in the X-ray band. It was launched on 15 October 1974 from the San Marco platform in the Indian Ocean 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.{{cite web | url=http://heasarc.nasa.gov/docs/ariel5/ariel5.html | title=HEASARC: Observatories - The Ariel V Satellite | publisher=NASA | access-date=2008-03-03 | archive-url=https://web.archive.org/web/20131227165403/http://heasarc.nasa.gov/docs/ariel5/ariel5.html | archive-date=27 December 2013 | url-status=dead }} 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.{{sfn|Smith|Courtier|1976|p=422}}

Plans for Ariel 5 were first discussed between the UK and US in May 1967 at the Ariel 3 launch. The Science Research Council (SRC) advertised a request for proposal for experiments in June. Experiments were formally proposed to NASA in July 1968.{{sfn|Smith|Courtier|1976|p=421}}

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.{{sfn|Smith|Courtier|1976|p=422}}

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.{{sfn|Smith|Courtier|1976|p=422}}

=Operation=

Ariel 5 was spin-stabilized.{{cite web|url=https://space.skyrocket.de/doc_sdat/ariel-5.htm|title=Ariel 5 (UK 5)|website=Gunter's Space Page|last1=Krebs|first1=Gunter|access-date=8 March 2020}} The satellite improved on the attitude control of Ariel 4.{{sfn|Dalziel|1979|p=413}} It used liquid propane that was expanded through a reducing valve and heated with the bulk tank temperature.{{sfn|Smith|Courtier|1976|p=429}}

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.{{sfn|Smith|Courtier|1976|p=429}}

=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 {{convert|abbr=on|3|cm2|sqin|3}}, and a bandpass of 3–6 keV. The ASM was designed to fit a resource budget of {{convert|2|kg|abbr=on}}, 1 bit per second, and 1 W.{{ cite journal |author=Priedhorsky WC |author2= Holt SS |title=Long-term cycles in cosmic X-ray sources |journal=Space Sci Rev |volume=45 |issue=3–4 |date=1987 |pages=291–348 |bibcode=1987SSRv...45..291P |doi = 10.1007/BF00171997 |s2cid= 120443194 }}

The sky survey instrument (SSI) had an angular resolution of 0.75 × 10.6°, with an effective area of {{convert|abbr=on|290|cm2|sqin}}, and a bandpass of 2–20 keV.

Mission

=Launch=

File:Lancio Ariel 5.jpg]]

Launch operations took six weeks, starting from the time the Guppy took off from Thorney Island.{{sfn|Smith|Courtier|1976|p=428}} The satellite was launched on 15 October 1974 from the San Marco platform in the Indian Ocean off the coast of Kenya.{{cite news|url=https://www.newspapers.com/clip/46389303/grand-prairie-daily-news/|title=Cooperative Space Mission Provides New Knowledge|newspaper=Grand Prairie Daily News|location=Grand Prairie, Texas|date=18 October 1974|via=Newspapers.com|page=8}}

=Operations=

The satellite was controlled via a mission control centre in Appleton Lab. It spun at over 10 revolutions/minute.{{cite web|url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1974-077A|title=Ariel 5|website=NASA Space Science Data Coordinated Archive|access-date=9 March 2020}} Ariel 5 operated until 1980.

Results

Over 100 scientific papers were published within four years of the launch.{{sfn|Harvey|2003|p=99}}

Notes

References

{{cite conference|conference=Automatic Control in Space: 8th IFAC Symposium|isbn=9781483158976|date=2-6 July 1979|location=Oxford, England|last1=Dalziel|first1=R.|title=The Significance of UK Spacecraft Control to Space Science|url=https://books.google.com/books?id=shajBQAAQBAJ}}
{{cite book|title=Europe's Space Programme: To Ariane and Beyond|last1=Harvey|first1=Brian|isbn=9781852337223|year=2003|publisher=Springer}}
{{cite journal|journal=Proceedings of the Royal Society of London|series=Mathematical and Physical Sciences|last1=Smith|first1=J.F.|last2=Courtier|first2=G.M.|volume=350|number=1663|date=1 October 1976|title=The Ariel 5 Programme|pages=421–439|location=Great Britain|doi=10.1098/rspa.1976.0115|jstor=78979|bibcode=1976RSPSA.350..421S|s2cid=128761336}}