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DOCEMENT RESUME ED 184 898 Sr 030 607 .TITLE Space refescope. INsnrano; National Aeronautics and SpaceAdministration, Huntsville, Ala. Gedrge C. Marshall Space Flight :enter. PUB DATE 80 NOTE 12p.; Illustrations will pot reproduce cfearly.

EDRS PRICE SF01/P:01 Plus Postage. . uscRIETORs *; Elementary Secondary Education; Higher Education; *Pamphlets; Science 2ducatiok; Scientific Eaterprise; *Space Sciences; *Technological Advancement I, IDENTIFIERS' *Telescopes

ABSTRAC2 - This pamphlet describes the , an unmanael multi-purpose telescope observatory planned,for la.unch into orbit by the in the 1990s. The dnigue capabilities of this telescope are detailed, the major elements of the telescope are described;'and its prOposed mission operatioms are outlined. (S)

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***************************************4****************************#0 * . Reproductiong supplied by EDPS are th6 best tat,.can be maie I* * from the original document. 4 * ************************** U.S. DEPARTMENT OF HEALTH, EDucAnctio WELFARE MAMMAL. INSTITUTE OF National Aeronautics and EDUCATION THIS DOZUMENT HAS SEEN REPRO-. Space Administration . DUCED EXACTLY AS RECEIVED FROM NEPERSON OR ORGANIZATION ORIGIN- ATING IT POINTS OF VIEW OR OPINIONS -STATED DO AIDT NECESSARILY REPRE- Maishall Space Flight Center SENT OFFICIAL NATIOhAL INSTITUTE OE EDUCATION POSITION OR POLICY

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Ttie Space Telescope is án 'unmanned multi-purpose optyial telescope observatory pianned for launch into Earth orbit by the Space Shuttle in the 1980s.The Marshall Space. Flight Center, Huntsville, Ala.; is NASA's lead center for ma'n- agement of the Space Tele- scope projebt.

APR 1 7 1996

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Why Astronomy ?

Astronomy deals with the enhanced by the Spac-e Telescope, of the evolution of. a star like our fundamental issues that face rea- envisioned today as'mankind's eye ' are very long compared with soning man: how did my world come to the univers.e for the next 20 years. .the.total lifetime of men on the into being, what is the order of the Some.may wonder why we need Earth, bi observing individual , what role does my world to look toNthe stars. Why, other stars in different phases of their play; and what is its future? thar; curiosity, should man strive changes, the can Answering these questions is to examine thefar reaches of the accurately picture the Sun from the challenge to th2 astronomer, cosmos? We look 1573catise the , cradle to grave. Even though the the.theolog* and the philosopher. missing pieces in thpuzzle bf the universe is abundant in its The'astronomer seeks to learnarid universe are out these. We want to phenomena and subjects, the ob-. understand the laws governing the know how it began, ,how it grew, sehrational nature of thisfscience structure and evolution of his hoyv it is changing, and what is its means that the astronbmer's 'universe by observation and ultimate fate. "eyes" are-only as good as his interpretation. The scale of distanceS.to,even imagination andA.uccesi in con- For more than a century, - the nearest stars is so great as to ceiving and realizing hew ways omers have dreamedof viewing the preyent the present generatiogs of of observing. sky through a telescope in space man from visiting them.for study. ,The view of a serene universe, outside the Earth's obscuring This`tnggls that the astronomer is , composed of stars and syStems of atrnotphere. Vyhi*.le,it may have only an observernot 'an experi- stars (galaxiqs), has given way in the been a tirea.rn f8i- ()berth, the menter. He cannot punch, squeeze, past ZO years to a picture of a violent Gerhian scientist who first men- melt, or perform Pperations on the universe, filled with many.cata.- tioned the possibility in0923, objects 'of -his study, but must lparn clysmic events accompanying the and even for those who discussed only from observing what nature is origin of 'and the death of it extenslwly in thelate'1940's doing. stars.' We now know of quasars, and eaffy 1950's, today it has' Fortunately, the same vastness of, neutran stars and possibly black become a reality. scale that prohibits our travel also holes, each of which gives off signals Relatively small telescopes are allows a richness of conditions 'to of ItA nature and exisience with no already in orbit, such as NASA's aPply and a host of idifferent obser- regard for the serisitivity of the eyes International Ultraviolet Explorer vable phenomena to occur. For of the most intelligent species, or for' and Orbiting Astronomical Observ- example,-we pan study regions of the paoperties of the atmosphere, of the third of a, rather common atory. ionized gaA that are so rarefied as But now NASA is developing a to surpass the best vacuums achiev- star.. much larger and more sophisticated able on.the E 6; and we can study This means that if we are to instrument called the Space Tele- collapSed st_,.so dense that all of get a 'complete viewfof the real scope, a multi-purpose.unm9nned the Earth could be compressed with universd we must continue to- build powerful telescopes and to optical telescope in Earth orbit, equal density into a sphere only observe from space iiself, where we scheduled to become operational 1,000 feet in diameter. in the 1980s. The profusion of observable see the universe as it really is The astronomer's capacity for objects can also be used to advan- not filtered by the terrestrial atmos - observation will be Aremendously tageY Although most of theiAlase% phere. 5 NEARBY This , in ttie constellation Andromeda, is just barely .visible to the naked aye. While it is our 'closest large neighboring galaxy, it is 'still 2.2 million light yearsaway. The Space Telescope will enable to study this galaxy, which is very similar to our own, and other celestial objects in far greater detail than ever before.

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It canibe argued that astronomy NASA's Space Shuttle,lhe Space is an eso,teric science, justifiable Telescope will orbit friigh above only on the grounds.pf fundamen- the hazy and turbulent atmosphere, tal curiosity; however, there is fur- where it will enable scZists to the0 justification in its study of see the universe moreearly. unique phenomena*. Nature pro- The Space Tele§cope is a superb vides conditions that.cannot be system that will fully exploit the duplicated-on the Earth and other advantages of space observations. conditions whose cost to duplicate lt is a natural next step in the cur- would be prohibi.tively expensive rent revolution in astronomy, a for basic research. revolution that history VII probably This means that we find condi- equate with Gillleo's inifention of tions that expand ot.d current the simple telescope 370 years ago. understanding of natural laws. Th history of science shows that it is when tljerexisting laws. are putlo . the mostdemanding tests that the greatest advances in understanding 'occur. This raises the real possi- bility that fundamental processes I first understood from astronomi- cal observations can, eventuaHy be ppplied to aid the Earth and its 4 ,* popuAtion. All types of observations are possible, from low-energy radio waves through the ultra-high- energy rays; but the greatest supplier of astronomical information is stiH the optical tele- scope. Since the turbulence of the SUPERNOVAE REMNANT This vs the Earth's atmosphere imposes prac- Crab Nebula in the constellation Taurus It is the remnant of a , or explod- tical limitations in all 'but a very ing star, that first appeared in 1054 A.D. selected few types of observa- Supernovae are very rare; only six have tions, the only practical successor ,been recorded in our galaxy in the past 2,000 years. They may flare to as much as to the giant Earth-based telescope is a billion times their original brightness. thiiiigh-qualityspace telescope. fading in less than a year The Sp'ace Tele- The Space Telescope Project scope will study these and many other will provide such a telescope. objects in the ultraviolet, visible and near infrared spectrum. Launched into Earth orbit by

2 What Space Telescope CanDo

The Space Telescope's unique 50 times.fainter than those seen capability for high angular resolu-, by the most powerful telescopes'. tion imagery, large auxiliary equip- Within the System, they tan ment payload and efficiency of monitor atmospheric and surface operation will make it the most . phenomena of the . powerful telesco`pe ever built, With a telescope in Earth orbit, enabling man to gaze seven times long time exposure images more 'farther into space than now than 1=0 times sharper tharrthose possible perhaps.to the outer from the ground can be achieved. edges of the universe. Another great advantageof The largestkirth-basedtele- orbital observation is the absence scopes in oper,ation today can- of atmospheric material that see an estimated two billion light absorbs the ultraviolet and infrared years, or about 12 billion trillion radiation froni stars. miles, intOspace. The Space Tele- Tlcerisper images of the e scope will be able to see much telescope, combined wifh the deeper 14 billion light-years. darker sky background, will Some scientists believe the universealso permit much fainter objects was formed nearly1,4 bi4lion years to be detected. By concentrating ago so the Space Teletcope mightthe starlighhinto a smaller provide views of galaxies at the timearea, the contrast with the they were forpetr*\ background (which is lower, due Studying the stars isn't 'merely to the absence of scattered light a of distance,however; it and airglow emission) is improved, cOMPARI N WITH EARTH-BASED, is also one of clarity. All Earth- while the concentration means TELESCOPE Resolution of the Space. TelescoPe will beCI tines better than bound seeing devices have dis- that the exposure times to reach a Earth.based telescopes. It will be able to torted vision because the Earth's given brightness level will be see objects that are 50 times fainter and atmosphere-blurs the view and reduced. sevOn times farther away than those we For faint object photography, are now able to obseyve While it is not smears the light. The clearer imagDs possible to depict exactly what will be seen, provided by the Space Telescope the Space Telescope should be the above illustration will serve as an will enable scientists to evaluate-theable to go perhaps 50 times , example At top, the tiny, hazy patch in the fainter than the some detection small circle is shown as it would be seen mass, size, shape, agearid evolution with an Earth-based telescope. The lirge of the universe more compre- system on the ground..One of its, circle at bottom shows the same area as it hensively. scientific instruments will use would appear with the Space Telescope With the Space Telescope, solid-state imaging-type sensors scientists will be able to look at of much higher sensitivity, in celestial sources such as quasars, sortie respects, than photographic 'galaxies, gaseous nebulae, and filmAn additional fringe bene- Cepheid variable stars which are, .fit of these sensors is the freedom " 6

3 SPACE TELESC9PE'S CAPABIL IES Eqrth's atmosphere,.while tran rent to visible light, filters out,m the electro- - magnetic spectrum.lAlso; haze; turbulent air currents, clouds and light pollution from cities limit the usef Olness of present tele- scopes. The Space Telescope will be able to, use.the entirevisible portion of the spec- trum, in addition to portions of the infrared and ultraviolet.

, .\ from thedimited storage.range of theqrbit other stars in the same way ph9tographic emulsion, thus per- the Earth orbits the Sun. Data in

mitting verY long periods of obser- .4. this area will tell us about basic vation and even fainter manitude. 'physiOal processes in ihe universe limits. and indicate the chances fckr the A further advantage,for observa- eiistente of other life-sUpporting tional programs lies in the access- Olanets. It will provide a ilew , ibility of all of the sky encl.& perspective on the neighboring%

24 hours of observing conditios. ..planets, giving continuing infor- 4 With ground-based obseni6tories, mation about their physical condi- most optical observations are made tions and atmospher.ethe kirixf of only during twilight and dark hour; informatior,i needed to build and and even theh onlyWhen it is reason-equip spacecraft for further explo-

ably clear. With the Space Telescope, .ration. ON-ORBIT SERVICE. Tshe unique capability it will be possible to mzike some Astronomical observations in the offered by Space Telescope for on-orbit obaervations even in sunlight past have often suggested potential servicing and uprating of itsequipment, using suited astronauts, will add%reatly to its (although not to the faintest levels) solutions to problems on Earth. For value as a scientific tool. Astronomers will be and realize about 4,500 hours of example, the first confirmation of able topereodicallyupgrade scientific observation per year. (Excellent nuclear fusion was from the study instruments to the latest stele-of-the-art In ,event of major repairs or refurbishment, the ground-based observaltories obtain of the Sun. If the quasars are as Sh-uttle would be able to retrieve the Space about 2,000 hours pef year.) intensely luminous as they appear., Telescope, return it to Earth and r aunch it The Space Telescope is expected they have the concentrated power later. to contribute a great deal to the of millions of stars. The Sun 'study of little-understood energy pro-would be pale in comparison. cesses in.cplestial objects the Are quasars really so powerful? early stages 'of star and. solar- Can their energy principle be system formation, such highly- used on Earth? For the first time, evolved objects as supernova with the Space Telescope, quasars remnants and stars, "can be seen well enough to inves- 'and the origin of the universe. tigate these possibilities. With the Space Telescope, scientists can look at galaxies so so. far away that they will be seen as 4 they were billions of years ago Tqy should have much to reveal about the birth ind growth of cosmic structures like our galaxy, The Space Telescope may be able to search for planets that

4 UGHT PATH This schematic shows how starlight enters the open front Emd of the Space Telescope, is projected from the INCCOUNO PRIMARY yONT primary mirror to the secondary,mirror,end is then directed to a focus inside the scien- tific jnstruments at rear. The light baffles e SECONDARY SCIENTIRC preclude unwanted light, which may have SURAOR 141STRUMEACTS been deflected off some part of the tele-

FORT 111APPLI scope, froin reaching the image formed IMAGE FORMED within thi scientific instruments. AT PRI POINT

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The Space Telescope System iii The Space Telescope'will be a primary mirror will project the image The apertures of the Scientific. long-lifetime general-purpose to a smaller secondary mirror in Instruments, are located at the telescope capabla of utilizing a front. The beain pf light will thenbe principal focus. Since stray light wide variety of different scienti- reflected back through a hole in suppression is extremely important fic instrUments at its plane. the primary mirror to the scientific in reaching..faint light levels, the It will weigh about 24,000 pounds instruments in ,the rear. forward end of the telescope is (11,000 kilograrns) and will have.a The pointing and stabilization con- enclosed and well baffled, with the aperlure door serving as a Sup length of 43.feet (13.1 meters) '..trol system can point the telescope to and a diameter of 14 feet (4.26 an accuracy of 0.01 arc-seconsi and meters). cln hold onto a target.fdr extended' The Scientific Instruments include The major elements of the periods within 0.007 arc-second. two;cameras, two spectrometers Space T..plescope will be an Optical, (This angle is only sligptly larger and a photometer. Telescope Assembly, a Support than that .made by a dimp when The Faint Object Camera, provided Systems Module and thet cientific viewed at a distance frOnl Washing- by the Eurppean Space.Agency, and. Instruments'. ton, D.C., to Bpston.) The resolving the Wide Field Planetary Camera The Optical kelescope Assembly power of two point images wilr be are distinguished by their fields of will mbunt a 94-inch (2.4-meter) about 0.1 arc-second. , view4 spatial resolution and wave- reflecting cassegrain-type telescope. The references ilfseFl for pointing lengthrange. Both instruments A meteoroid shield and sunshade stability will be accomplished usinfg cover the ultraviolet and blue .will protect the optics. precision gyros and bright field regions of tile spectrum. The telescope itself withave a strs ors ''guide- stars. The Wide Field Planetary Camera Ritchey-Chretien folded optical The Scientific Instruments will covers the rei3 and near-infrared system with the secondary provide-the means of converting the regions aA well'. The Faint Object mirror inside of the prime focus. telescope images to useful scientific Camera has a very small field of The primary mirror will be made data. view, but can use the highest spatial 'of ultra-low expansion glass. The instruments, and their resolution which the Space Tele- The mirror will be heated during sensors, located directly behind the scope optics cah deliver. The Wide operation to about optical shop telescope, will co-mmunicate imavges' Field Planetar.y Camera covers a tempetatures (70°F) 'to m'inimize in a variety of ways. The modular field at least 40.times larger, but variations from its original accuracy. instruments will fit behind the focal with a resolution degraded by a Additional heat required to maintain plane and 4will contain imaging factor of two to four. the 70°F temperature willcome' systems, spectrum analyzers (to The two spectroglaphs, the High \ from electrical strip heaters which find out about atomic structure Resolution Spectrograph and the `will radiate to the back of the and material content of objects Faint Object Spectrograph, provide mirror. .obserted),. and light intensity and a wide range of spectral resolutions The open front end of the Space . polarization calibrators. Devices which would btit impossible to cover Telescope will be similar to most for exact control of temperature. in a single instrument. Bpth instru- Earth-bound telescopes and witi direction and stability, and the Ments will record ultraviol4 admit light to the primary mirror equipment to generate power will qe radiation. Only the Faint 04.ject in the rear of the telescope. The located in similar modular packages. Spectrograph covers the visible SUPPOWYSTEMS MODUCE Overall . size of the Space Telestopeii 43 feet (13.1 meters) long by, 14 feet (4.28 meters) in diameter. This illustration shows the Support Systems Module, which contains the very precise pointing and stabilization control system, communications, thermal control, data management and electric power systems, land solar panels for electrical powir generation.

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and red regions of the spectrum.

.The fifth instrument, the High Speed Photometer, is a relatively. SiMPle.device.capable of measurjng rai?id brightness variability over

tiMe.intervals as short as 9.0001 411. second: It can also be used to . measure ultraviolet polarization and to calibrate other instruments. It is expected that competition for new instruments may be opened GRAPNtTE EPDXY every few years to guarantee that' METERING TRUSS the Space Telescope instrument SECONDARY MIRROR ASSEMBLY payload represents the best possible configuration. The Sapport Systems Module - CENTRAL BAFFLE will enclose the Optical Telescope Assembly and Scientific Instru- FINE G IPANCE SENSOR (31 ments and also provide all inter- faces wilh the Shuttle Orbiler. The module will contain a very AXIAL SCIENTIFIC INSTReAENT precise pointing.and stabilization AL,L(MINUM MAIN control systerk the communications BAFFLE system, thermal control system, data management systerh and electric power system. . 2 4 METER PRIMARY MIRROR Electrical power to operate the telescope %Aryl be provided-by batt- MAIN RING eries which are charged by the two solar panels during the Sun side of r1 RADIAL SCIENTIFIC 'Its Earth orbit. INSTRUMENT FIXED READ STAR TRACKERS 13) Images received by the telescope. & RATE GYRO ASSEMBLy Will be transmitted to Earth by telemetry.

OPTICAL TELESCQPE ASSEMBLY This through a hole in the prin\ary mirror for Is a cutaway view of the Optical Telescope analysis by sevelil ;entitle instruments, Assembly, which fits inside the Support including a Faint et Camera, Flaint Object Systems Module. Light is projected by ?he Spectrogoph, High Speed Photometer and . . 94-inch (2.4 meter) primary mirror to the r Wide Field Planetary Camera_ secondary mirror, a n d from there back

i) 6 DATA ACQUISITION The Speee Tele- scope will be controlled remotely by ground stations. Data acquired by the tele-

%IF scope will be sent electronically to a computer and then converted to formats suitable for scientific analysis. NASA's Track- ing and Data Networkvvhich includes the rracking and Data Relay Satellite System and 'ground tracking stations, and the NASA Communication Networkwill be used to complete,the communications link between ttie Space Telescope and the ground operational systems.

Mission Operations The Space TelesCope is a new manner similar to that of ground- the Space Telescope wl:flktie posi- concept in space-borne astronom- based telescopes. The five instru- tioned in space by the Orbiter ical observatories. Its long design ments can be, selected as apprQ- remotatmanipUlator arm'. lifetime and the capability of priatefor specific observations Checkout' ---^As the Orbiter , refurbishment and scientific instru- and the telescope can be pointed remainsnearby for 'help if needed, ment replacement will enable it to to targets of interest. Plans for the Space Telescope will, receive operate at the forefront of asfro- orbital operations include a an initial ctrckout from ground- nomical research .for two decades or limited amount of interaction based operators to make sure that mvre. Due to the Space Telescope's between the observer and the all systems are operating properly. unique scientific importance, its telescope-during the observation. For the Orbiter to retrieve the operations are designed for maxi- There are plans to establish an telescope, the steps will be mum flexibility while at the game indeperident organization, the reversed. time ipsuring spacecraft safety Space Telescope Science Institute,' On-orbit Service During re-visit,. and operational efficiency. to develop and control the ,science the Space Telescope will becdptured .< The Space Telescope wNI orbit programs carried out using Space and positioned in the Shuttle's pay- the Earth at a nominal altitude of Telescope. Observers who use the load bay by the Orbiter remote approximately 310 mile§ (500 telescope would go to the Institute manipulator' arm. A crew in space . kilometers) with an orbital incline- to participate in an observation. suits will provide necessary service, tion of 28.8 degrees. Principal Shuttle/Space! Tele- making repairs and replacing equip- The Space Shuttle will launch scope mission operations phases will ment. This capability will make the Space Telescope into orbit, and include: launch, orbital operation, Space Telescope a practical long- also serve as a base from which deployment, checkout, on-orbit term reality. astronauts may make repairs by service, and re-entry. # Re-entry The Space Telescope replacing modular components, Launch Two reusable solid in the Orbiter's cargo bay will be including new instruMent packages.proaellant boosters and an external isolated from the intense heat Each modular package can be fuertahk are required to launch the generated duriog re-entry. After it replaced in orbit without affecting Sh'uttle Orbiter (carrying the Space enters the Earth's atmosphere, the- the overall system. The Shuttle can Telescope in its cargo bay) into Orbiter will land like a conven- also bring the telescope back to- space. The boosters will separate tional air'plane. Servicing and repairs Earth, if necessary, for extensive and parachUte into the ocean for will then prepare the Space Tele- maintenance or overhaul, and later recovery and re-use. The Orbiter will scope for its neat mission. relaunch it.\The plan is to update then be drivenr by its liquid-propellant the scientific instruments, bn a engir113s. ..,.iceopriective basis, in Orbit after about Orbital Operation After orbital wo-and-a-half years and to relurn insertion and circularization," the Space "firlescope to Earth via thethe Orbiter will be maneuvered b, Shuttle after five years for major finto the Proper position and the refurbishment. Space Telescope will be raised in Although in orbit, the Space prepaiation for deployment. ;Telescope will be operated in a 'After a _preliminary theckout,

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1 The Space Telescope Team NASA's Offige of Space Science, program to implement NASA policy, NASA Headqdrters, Washington, and detailed science planning and D.C., issesponsible forioverall direc-routine operations. The Institute will tion of,the Space Telescope program.carry out NASA science objectives, The Marshall Space Flight Center,solicit and select observational, Fiuntsville, Ala., is NASA's lead cen-proposals and coordirrate research ter, responsible fOr overall project and international participation. management. It will determine general viewing 4 The Gbddard Space Flight Center,schedules, target sequende and Greenbelt, Md.; is responsible for thetarget availability within the context scientific instruments, mission of spacecraft constraints. The Insti; operations and data reduction.' .. tute will also reduce and analyze The Johnson Space _Center is data, conduct basic research, evalu- responsible 4of the Space Shuttle ate and disseminate the science and flight crew operations. data arid store the data in archives. es.) The Kennedy Space Center is responsible fer th,e Space Shuttle 4. launch operations. -.European Space Agency members will provide one'of the scientific instruments, as well as the solar arrays, and will participate in flight operations. The Space Telescope pnme con- tractors are Lockheed Missiles and Space Company, Sunnyvale, Cal., responsible for the Support Systems. Mddule and system engineering, and the Perisia..15er Corp., Danbury, Conn., responsible for the 4 Optical TelescopeAssemiry. A total of 45 scienfisls have beenselecited by NASA to partici- pate in the design and ea.rly opera- tional phases of the Space Telescope project in a variety of categories. NASA will oversee the opeiation, of an independent Science Insti- tute responsiblefor conducting 1 9 an overall Space-Telescope science