nasa facts a-r-i-e-l first international satellite

8/7/2019 NASA Facts A-R-I-E-L First International Satellite

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NASA FA ( TSAN EDUCATIONAL SERVICES PUBLICATION OF THE

NATIONAL AERONAUTICS AND SPACE ADMINISTRATIONNASA FACTS (C-62) Page 1A-R-I-E-L -~ 68FIRST INTERNATIONAL SATELLITE ,.

. ARIEL I N ORBIT -Artist 's conception of the United Ki ngdom-United States satellite in space .INTERNATIONAL COOPERATION

Ariel, th e joint United Kingdom-Uni tedStates satellite launched April 26, 1962, dramatizes the steadily expanding program of international cooperation in the peaceful explorationand utilization of space. Named by the UnitedKingdom ' s Prime Minister Harold MacMillan fo rthe sprite in Shakespeare's Tempest, Ariel is thefirst of severa I joi nt satell ite proj ects pi a nnedby the United States an d other nations . It isalso the world ' s first internationally conceiveda nd executed sate II ite .

This joint United Kingdom -Un i t ed Statessatellite developed from a proposal by UnitedStates representatives at the March 1959 meet-

ing of COSPAR, the Committee on Space Re-search of the International Council of ScientificUnions. At that meeting, the United States of-

DEFINITIONSlonosphere- The layer of atmosphere beginning about

40 miles above the earth 's surface, consisting of ionizedair, which can reflect certain ~ a d i o signa ls.

lon-A molecule or atom wh ich has lost or gained anelectron, thereby acquiring an electric charge .

Proton-A positively-charged constituent of an atom;the nucleus of the light isotope of hydrogen .

Electron-The smallest known particle of negative elec-tricity. It is a constituent of the atom.


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NASA FACTS format is designed fo r bulletin-board displayuncut or fo r 8 " x lOY," looseleaf notebook insertion whencu t along dotted lines an d folded along solid lines. Fornotebook ring insertion, punch a t solid dots in th e margins.

Page 2fered to launch payloads or complete satellitesprepared by foreign scientists. The UnitedKi ngdom was one of a number of nations toaccept the offer.

LlFT-OFF-NASA Delta launch vehicle carryingBritish Ariel payload rockets from launch padat Cape Canaveral, Florida, 1 p. m. E.S.T.,April 26 , 1962.

SCIENTIFIC OBJECTIVESAriel is designed chiefly to contribute toman's knowledge of th e ionosphere, an elec

trified region of the atmosphere extending fromabout 40 to several hundred miles above earth.

The ionosphere is formed by absorption inthe earth's atmosphere of X-rays and ultravioletIi gh t from the sun an d by impact of solar energetic particles (mai nly protons) on the atmosphere. As a result, atmospheric molecules arebroken into free electrons and p o s i t i v ~ l y chargedions . (See DEFINITIONS . )

NASA FACTS will be regularly mailed only to addressees whorequest it from: Office of Educational Programs and Services,NASA, 400 Maryland Avenue SW., Washington 25 , D.C.

NASA FACTS (C-62)

" Th is joint enterprise reflects great credit on the Br itish andAmerican scientists and technicians concerned. It provides a fine start to the United States program of international cooperation in space. "

Harold MacMillanPrime Mi n ister of theUnited Kingdom

From a practical standpoint, the ionosphereserves as a radio mirror for reflecting messagesfrom on e point on earth to another. A majordrawback to its use in radio communications isthat its characteristics change with season, timeof day, and solar events. Solar flares so disrupt the ionosphere that it absorbs radio waves,preventing messages from being reflected to thereceiver.

Dependence on the ionosphere fo r communication will be diminished when communicationssatellite systems are perfected. However, demand fo r communications channels is climbingso rapidly that reliance on the ionosphere fo rsome communication is expected to continueindefinitely.

Ariel's instruments measure densities andtemperatures of electrons and characteristics,quantity, and distribution of ions. They alsomonitor solar X-rays and ultraviolet light tocorrelate behavior of th e sun with changes inthe ionosphere.

Another Ariel exper iment is designed tostudy th e relationship between disturbanceson the sun and cosmic rays in the earth's vicinity. Cosmic rays consist of a mixture of protons, nuclei of elements such as hydrogen, andother particles that have been accelerated toenormous energies.

Eruptions of sunspots or solar flares are usually followed by a decrease in the intensity ofcosmic radiation reaching the earth. It is theorized that during solar disturbances, th e sunhurls low-energy protons which drag th e solarmagnetic field with them_ When this field extends toward earth, it deflects some of the cosmic particles, reducing the quantity reachingearth.


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NASA FACTS (C-62) Page 3

MASS SPECTROMETER PR08E - ---1...

ELECTRON TEMPERATUREPftOBE

ASPECT SENSOR

ELECTRON [)f/lllSITYB"""

INSIDE VIEW-Cutaway of Ariel showing principal instrumentation prepared by the United Kingdom andequipment prepared by the United States.ORBITAL ELEMENTS

Ariel orbits the earth about every 101 minutes. Its apogee (farthest flight from earth) isapproximately 760 miles; its perigee (closestapproach to earth) about 244 miles. Its orbitis inclined about 54 degrees to the equator,meaning that it passes over an area stretchingfrom 54 degrees north to 54 degrees southlatitude.

STRUCTURAL MEASUREMENTSThe 132-pound satellite is 23 inches In di

ameter and 10 1 Y16 inches high. In orbit, withsolar cell paddles, booms, an d antennas extended, i t measures about 10 feet across.(Solar cells convert sunlight to electricity fo r running the satellite ' s instruments.)

PRINCIPAL PARTICIPANTSScientists of the United Kingdom developed

and built the experiments. The Royal Society'sBritish National Committee on Space Researchselected experiments in consultation with theNational Aeronautics and Space Administration

(NASA). The University of Birmingham pre-pared the equipment to measure electron density. Imperial College, London, developed theinstruments to gauge intensities of cosmic rays.University College, London, made the instruments fo r measuring temperatures and concentrations of ions an d electrons in earth's vicinityan d intensities of X-rays and ultraviolet radiation from the sun. The University of Leicestercollaborated in the X-ray experiment.

The National Aeronautics and Space Act of 1958 re quires that NASA " provide fo r the widest practicable andappropriate dissemination of its activities and the resultsthereof . " The act also requires that NASA work withnationals of other countries in development of space tech nology an d " in the peoceful applicat i on of the resultsthereof. "

NASA's Goddard Space Flight Center, Greenbelt, Maryland, was responsible fo r the satellite's structure and auxiliary instrumentationincluding telemetry, communication, recording,and power supply. NASA also supplied theDelta launch vehicle, the faci l i t ies, and theservices fo r placing Ariel in orbit.


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COOPERATIVE SPACE PROGRAMSThe countries listed have cooperative space programswith the United States in the categories noted :

SatellitesCanada, United Kingdom , and Italy . (Others contem-plated .)

Sounding RocketsArgentina, Australia, Canada, Denmark, France, Italy,Japan , New Zealand, Norway , Pakistan , Sweden

Ground-Based MeteorologyArgentina , Austral ia, Austr ia, Belgium, Brazil, British EastAfrica, Burma, Chad, China, Colombia , Costa Rica ,Czechoslovakia, EI Salvador, Federation of Rhodesia andNyasaland, France, Hong Kong , Hungary, Iceland, India,Iraq , Ireland, Japan, Mauritius, Netherlands, NetherlandsN ew Guinea, New Zealand, Poland, Portugal, Republic ofSouth Africa, Sudan, Switzerland, Thailand, United ArabRepublic , United Kingdom, W est Indies Federation

CommunicationsBraz i l, Federal Republic of Germany , France, Italy, UnitedKingdom

Track ing and Acqu iring Data from SpacecraftArgentina, Australia , Brazil, Canada, Canton Is., Chile ,China, Ecuador , Federal Republic. of Germany, India,Iran , Israel, Japan, Mex ico, Netherlands, Nigeria, Peru,Philippines, Portugal, Republ ic of South Africa, Spain,United Kingdom , Zanzibar

Goddard Space Flight Center processes transmissions from the satellite and sends them to theUnited Kingdom fo r analysis.

Scientific direction of Project Ariel is pro-vided by Homer E. Newell, Director, Office ofSpace Sciences, NASA Headquarters, and bySi r Harrie Massey, Chairman of the British Na -tional Committee on Space Research. Projectmanagers are M. O. Robins, University College,London, and Robert C. Baumann, Goddard SpaceFlight Center.

EIGHT COUNTRIES TRACK ARIELMinitrack stations in eight nations are coop-

erating in tracking and gathering data from thesatellite. The Minitrack network includes stations at Antofagasta, Chile; Blossom Point,Maryland; Esselen Park, Republic of South

,Afr ica; East Grand Forks, Minn.; Fairbanks,Alaska; Fort Myers, Fla.; Mohave, Calif.; Lima,Peru; Quito, Ecuador; Santiago, Chile; St. Johns,Newfoundland; Winkfield, England; Woomera,Australia. In addi t ion, stations of the BritishDepartment of Scientific and Industrial Research

Fo r sole by the Super intendent of Documents, U.S . Government Printing OfficeWashington 25 , D.C. Price 5 cents

._ _ . .NASA FACTS (C-62)" Space science is one science that is obviously inter-

national. You have to work on a global scale to do theiob properly. "

Sir Harrie MasseyChairman of the BritishSpace Research Committee

are participating in the experiment. Allstations funnel data collected into th e GoddardSpace Flight Center.

ARIEL WILLBROADCAST FOR ONE YEAR

The satellite is designed to transmit informa-tion fo r a year. Redundant switching systemshave been installed to assure that it goes of f theair on schedule, leaving its radio channel freefor other experiments. The satellite is expectedto remain in orbit fo r several years.

RESULTS TO BE SHARED WITH WORLDResults of Ariel experiments, expected to contribute significantly to scientifi,c knowledge, willbe shared with the world scientific community.In perspective, however, th e most important result of this first international satellite may wellbe the great step forward that it represents to-ward global cooperation in space. It is anoutstanding example of how peoples can unitetheir energies and talents in future space proj-ects fo r the benefit of al l mankind .

TELEGRAM FROM UNITED KINGDOM MINISTER FORSCIENCE

JAMES E. WEBB, ADMINISTRATORNATIONAL AERONAUTICS AND SPACE ADMINISTRATIONWASHINGTON, D.C.

I SEND YOU MY FULLEST CONGRATULATIONS ONOUR FIRST JOINT SATELLITE . WE OWE YOU A GREATDEBT OF GRATITUDE FOR THIS OPPORTUNITY; IT WILLADD IMMENSELY TO THE WARMTH OF ANGLO-AMERICAN RelATIONS, AND SETS AN EXAMPLE TO THEWORLD IN INTERNATIONAL COOPERATION IN SCIEN TIFIC SPACE RESEARCH.

FINALL Y, ON BEHALF OF THE AMBASSADOR, IWOULD LIKE TO EXTEND THE EMBASSY'S WARMESTCONGRATULATIONS TO ALL CONCERNED IN THISHIGHLY SUCCESSFUL VENTURE AND IN SHAKESPEARE 'SWORDS, TO SALUTE ARIEL : "THEN TO THE ELEMENTSBE FREE, AND FARE THEE WELl. "

LORD HAILSHAMMINISTER FOR SCIENCE


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Page 6MAGNETIC FIELDS FOUND

EVERYWHERE IN SPACEData from Mariner's magnetometer, an instru

ment that detects and gauges the force and direction of magnetic fields, were remarkable in theirgreat number and continuity. Mariner reportedthat magnetic fields were nearly always present asit raced through interplanetary space.

Scientists believe that the interplanetary magnetic fields are parts of th e sun's magnetic fieldthat the solar wind has distributed throughoutspace. Typically, the interplanetary magneticfields were found to be weak compared to earth's.Generally, they ranged from five to ten gamma,with precipitous increases to 25 or more gammafollowing sudden solar disturbances.

COSMIC RADIATION ININTERPLANETARY SPACE

During its entire flight, Mariner reported aboutthe same amount and intensity of cosmic radiation. This constancy is considered a significantaddition to scientific knowledge; bu t its implications will have to be clarified by additionalexperiments.

Cosmic rays are made up of protons (nuclei ofhydrogen atoms), alpha particles (nuclei of helium atoms), nuclei of atoms heavier thanhydrogen and helium, and electrons. They havevelocities almost as great as the speed of l ight(about 186,000 miles per second) and energiesin the millions, billions, and trillions of electronvolts. (The electron volt is a scientific measurement unit for energies of atomic particles.)

Cosmic rays are the most penetrating kind ofradiation, theoretically being able to pass throughlead walls as thick as a thousand feet. Mostcosmic rays come from outside of the solar sys-tem, usually from within our vast Milky Waygalaxy bu t sometimes from other galaxies. Ourown sun produces some cosmic rays, particularlyduring solar flares and other disturbances.

Both cosmic rays and th e matter in the solarwind are atomic particles. However, solar windparticles have comparatively lo w energies, in thehundreds and thousands of electron volts. De-spite the great disparity in individual energies,the aggregate energy of the solar wind is fa rgreater than that of al l cosmic rays in the regionof the solar system studied by scientific space-

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craft. This is because, in this region at least,solar wind particles outnumber cosmic ray parti-cles by about a billion to one.

Mariner reported a scarcity of cosmic ra y protons below the level of 800 million electron volts.This scarcity is attributed to interplanetary magnetic tields that permeate th e solar system anddeflect lower-energy cosmic rays.

If a space traveler had journeyed to Venus atthe time of the Mariner flight, he would have absorbed a total of 3 roentgens of radiation. Thisdosage is well within the tolerable limits for manduring a four-month period.

MICROMETEOROID IMPACTS FEWIn 1700 hours of recorded data, Mariner

registered only two impacts with micrometeoroids-t iny bits of matter in space. Comparisonof these data with information from earth satellites would indicate that micrometeoroids are10,000 times more abundant near earth thanalong Mariner's trajectory in interplanetary space.Moreover, no concentration of micrometeoroidswas detected around Venus such as occurs aroundearth.

Information about micrometeoroids is of practical importance in design of spacecraft and isbelieved essential to study of the origin and evo-lution of the solar system.TRACKING DATA ADDING TO KNOWLEDGE

The precise tracking data acquired through theMariner II experiment have prov ided basic information that is contributing to refinement of important measurements . Among them: the massof the moon; the mass of Venus; the Astronomical Unit (AU) which is the mean distance fromearth to sun and the yardstick fo r measuringdistance in the solar system; and the exact locations of spacecraft tracking stations on earth.

These figures not only will increase scientificknowledge but also are vital to planning ofmanned lunar and interplanetary voyages.

MARINER ESTABLISHED NEWCOMMUNICATIONS RECORD

Contact was maintained with Mariner II untilit was 53.9 million miles from earth. This shattered the previous long-distance communications