Ariel 3

In 1961 the UK Space Research Group accepted proposals for experiments to be carried on the third satellite of the Ariel programme. The British National Committee for Space Research selected experiments from those proposals and submitted them to NASA in 1962. The scientific objectives for the mission were selected in January 1963, and full work on the satellite began in early 1964 due to organisational and financial difficulties.{{sfn|Ladd|Smith|1969|p=480}} A total of 5 craft were constructed. One prototype, two engineering models, the final satellite and a flight spare.{{cite journal |last1=Campbell |first1=F. P.|date=December 1966 |title=Orbiting A High Atmosphere Experiment |journal=Weather |volume=21 |issue=12 |pages=422–428 |doi=10.1002/j.1477-8696.1966.tb02797.x |bibcode=1966Wthr...21..422C}} The flight spare was later used as the basis of Ariel 4.{{sfn|Dalziel|1975|p=163}}

File:Ariel 3 satellite nickel-cadmium battery pack - Science Museum, London.jpg

Power could be drawn from the batteries or the solar panels. The batteries were considered the least reliable component in the system so this method was devised to mitigate the issue.{{sfn|Sketch|1969|pp=493–494}}

The spacecraft weighed {{convert|197|lb|order=flip}}.{{sfn|Ladd|Smith|1969|p=479}}

Ariel 3 carried five experiments.{{sfn|Ladd|Smith|1969|p=481}} The experiments measured properties of the thermosphere as well as detected "terrestrial radio noise" from thunderstorms and measured large-scale galactic radio frequency noise.{{sfn|Ladd|Smith|1969|p=481}} Ariel 3 was also fitted with a series of mirrors to observe the spin of the satellite.{{sfn|Dalziel|1979|p=414}}

High-speed data was transmitted continuously to the Satellite Tracking and Data Acquisition Network (STADAN). Low-speed data was recorded on tape recorders and was transmitted to ground stations in the high-speed mode when commanded.{{sfn|Ladd|Smith|1969|p=485}}

Three experiments expanded on data from the previous two missions. Two experiments collected data on naturally occurring radio noise.{{sfn|Ladd|Smith|1969|p=481}}

The launch was originally planned for Wallops; Ariel 1 and Ariel 2 had both launched on the East coast. In 1964 experimenters requested a change to the proposed orbit, from an inclination of 50–70° to 78–80° to maximize coverage at the geomagnetic latitude. This change precipitated the launch site moving to the West coast.{{sfn|Ladd|Smith|1969|pp=482–483}}

It was launched from Vandenberg Air Force Base on 5 May 1967 aboard a Scout rocket.{{cite web |url=http://news.bbc.co.uk/onthisday/hi/dates/stories/may/5/newsid_2511000/2511263.stm |title='On This Day' for May 5, 1967 - First all-British satellite 'Ariel 3' launched |work=BBC News |date=May 5, 1967 | access-date=1 January 2010}}{{cite web |url=https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1967-042A |website=NASA Space Science Data Coordinated Archive |title=Ariel 3 |access-date=24 March 2020 |df=dmy-all }} This made it the first artificial satellite designed and constructed in the United Kingdom.{{sfn|Ladd|Smith|1969|p=479}}

Ariel 3 had an orbital period of approximately 95 minutes, with an apogee of 608 km and a perigee of 497 km. It initially spun at 31 rpm for stability, though by the time the Ariel 3 deorbited, it had slowed to a rate of about 1 rpm.

On 24 October 1967 the tape recorder aboard Ariel 3 began to malfunction. This restricted observation to real-time operation only. Nevertheless, as of May 5, 1968, after one year in orbit, the satellite's five experiments were still functioning and had returned 400 million bits of usable data on the upper atmosphere.{{cite web|title=Aeronautics and Astronautics, 1968|url=https://history.nasa.gov/AAchronologies/1968.pdf|access-date=28 April 2023|publisher=NASA|page=105}} Ariel 3 suffered from a significant power failure in December 1968, restricting the satellite's operation to daylight hours only. The satellite was completely shut down in September 1969. Its orbit decayed steadily until on 14 December 1970 when Ariel 3 re-entered Earth's atmosphere.

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{{Reflist}}

• {{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 journal|title=An Introduction to the Ariel III Satellite Project|last1=Ladd|first1=A.C.|last2=Smith|first2=J.F.|location=Great Britain|date=August 12, 1969|volume=311|journal=Proceedings of the Royal Society of London|issue=1507|pages=479–487|doi=10.1098/rspa.1969.0129|jstor=2416326|bibcode=1969RSPSA.311..479L|s2cid=129064735}}
• {{cite journal| issn = 0080-4630| volume = 311| issue = 1507| pages = 489–499| last = Sketch| first = H. J. H.| title = Description of the Ariel III Satellite Project| journal = Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences| date = 1969| doi = 10.1098/rspa.1969.0130| jstor = 2416327| bibcode = 1969RSPSA.311..489S| s2cid = 140671893}}
• {{Cite journal| issn = 0080-4630| volume = 343| issue = 1633| pages = 161–165| last = Dalziel| first = R.| title = The Ariel 4 Satellite| journal = Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences| date = 1975| doi = 10.1098/rspa.1975.0057| jstor = 78859| bibcode = 1975RSPSA.343..161D| s2cid = 202574658}}

• [http://www.chilton-computing.org.uk/acl/jpgs/aerial3.jpg Photograph that depicts Ariel 3]
• [http://news.bbc.co.uk/onthisday/hi/dates/stories/may/5/newsid_2511000/2511263.stm On This Day for May 5, 1967] BBC News
• [https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19670014008.pdf NASA release 67-96]
• [http://www.chilton-computing.org.uk/acl/applications/satellite/p003.htm Chilton Computing]

{{Ariel programme}}

{{Orbital launches in 1967}}

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Category:Spacecraft launched in 1967

Category:Satellites formerly orbiting Earth

Category:Space programme of the United Kingdom