OSO-G Press Kit

8/8/2019 OSO-G Press Kit

1/39

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WO '-41z5WASHINGTON,D.C. 20546 WO 3-6925FOR RELEASE: SUNDAY

August 3, 1969RELEASE NO: 69-112

P PROJECT: OSO-GE contentsSGENERAL RELEASE-------------------------------------- 1-6ENGINEERING FEATURFS------------------ -- 7-8

OSO-G EXPERIMENTS-----------------------------THE SUN: BACKGROUND INFORMATION---------- --------- 10SOLAR GLOSSARY--------------- ----- ___-------- 11-12OSO PROGRAM SCIENTIFIC RESULTS---- ---------------- 13-19DELTA LAUNCH VEHICLE--------------- ----- ------ 20NOMINAL OSO-G LAUNCH SEQUENCE, FLIGHT EVENTS--------- 21OSO-G FACT SHEET----------------------------------22-23OSO-G TEAM---------------------------------- 24-25

T

7/30/69..... . . . il- ii .. .... .....____,,.__... .


2/39

^l^ / _ ___- - - ____NE WS NATIONAL AERONAUTICS AND SPACE ADMINISTRATION (202) 962-4155WASHINGTON, D.C. 20546 TELS: (202) 963-6925FOR RELEASE: SUNDAY

August 3, 1969RELEASE NO : 69-112

SIXTH ORBITING SOLAR OBSERVATORY

The sixth spacecraft in the Orbiting Solar Observatory(OSO) program is scheduled to be launched by th e NationalAeronautics and Space Administration no earlier than August 8,1969 at 3:52 a.m. EDT, from Cape Kennedy, Fla.

Designated OSO-G (to be called OSO 6 if orbit isachieved), the 640-pound, spin-stabilized observatory willbe launched by a two-stage Delta N rocket. The planned orbitis circular, 350-statute miles above the Earth, with an in-clination of 33 degrees to the Equator and an orbital periodof 96 minutes.

OSO-G carries seven different scientific experimentsweighing a total of ?27 pounds. Providing the experiments arethe Harvard College Observatory, Rutgers University, th eUniversity of Nev, Mexico, the Italian University of Bologna,the University College London, the U. S. Naval ResearchLaboratory and the Los Alamos Scient:fjic Laboratories.

-more-


3/39

-la-

-more-


4/39

-2-

As the first series of spacecraft designed exclusivelyto study the Sun, the OSOs are the most important aspect ofNASA's Solar Physics Program.

The program, begun in March 1962 with th e launching ofOSO 1, consists of eight spacecraft.* Studies are currentlyunderway to add three advanced observatories to the program.

Understanding the mechanics of th e Sun is of vital im-portance not only to science but to all of mankind. This isbecause th e Sun dominates our existence and sustains life onEarth. Only a slight increase in its energy could melt thepolar ic e caps and submerge all the major cities of the world.A slight decrease in its energy could bring about another iceage. Solar storms disrupt communications and navigationsystems. The enormous gravitational attraction of the Sunaffects everything in the solar system.

Study of the Sun by ground-based instruments is hampered--and in some cases impossible--because of the Earth's atmos-phere which screens ou t major portions of the Sun's radiation.Thus, the Sun must also be observed from above the atmosphereif the complete nature of solar radjatlon, particularly in theultraviolet, X-ray and gamma-ray regions, is to be determinedand correlated.-OSO 3, launched August 25, 1965, did not achieve orbit.

-more-


5/39

-3-The experiments carried by OSO-G, as a continuation of

earlier OSO scientific objectives, are designed to studyevolutionary changes in various features of the Sun, withspecial emphasis on solar active regions. These experimentswill operate during a time of near peak activity in th ecurrent 11-year solar cycle.

A new feature of OSO-G is that for the first time inthe program an OSO has the capability to perforr an offsetpoint and small offset raster scan to study in letail ultra-violet and X-ray spectra at any point on the solar discand within a few arc minutes above the limb or edge of theSun's disc.

This capability, with its enhanced time and spatialresolution, should allow significant advances to be made in ourknowledge of conditions in the Sun's chromosphere--the solaratmosphere--as well as in the corona--the outermost layer ofth e Sun visible only through special instruments or duringa total solar eclipse.

As with its predecessors, the design lifetime of OSO-Gis six months.

-more-


6/39

-4-As was the case with earlier spacecraft in the series,

OSO-G is designed in two sections: an upper sail-likestructure which carries experiments to be pointed towardthe Sun; and a nine-sided base section called the wheelwhich carries non-directional scanning experiments and thebasic spacecraft support equipment.

The spacecraft is stabilized in orbit by its wheel sectionwhich spins like a gyroscope at about 30 rpm. When thespacecraft is in view of the Sun, the sail section automaticallypoints toward it. Simultaneously, the spin axis of the space-.craft is maintained roughly perpendicular to the directionof the Sun by using gas jets and a magnetic coil. The point-ing accuracy of OSO is better than one minute of arc. This isroughly equivalent to sighting a globe 18 inches in diameterfrom a distance of one mile.

The first two OSO spacecraft were launched successfullyfrom Cape Kennedy on March 7, 1962 (OSO 1) and February 3,1965 (OSO 2). The third OSO, launched August 25, 1965, failedto orbit. A fourth OSO (OSO 3) was successfully launchedMarch 8, 1967. OSO 4 was launched successfully October 18,1967, and it was followed by OSO 5 on January 22, 1969.

-more-


7/39

...... ... ::..::::- : ..:::"::-...... .: ...:: _ ................ . .. ... .... ...... .---=.. .-..- . .. .

.. ...... . . ..

. .

-----.-------

_WIT. ......... ...

. . .... ....

Al !k i


8/39

-5-Both OSO 1 and 2, surpassed their designed lifetimes

and together provided more than 8,600 hours of scientificinformation including the first long duration observationsof the X-ray and ultraviolet spectra of the Sun.

OSO 3 recently passed its second year in orbit andcontinues to operate well. The satellite is now providingseven and one-half hours of real time data daily.

OSO 4 recently passed its 20th month of successfuloperation and is also providing seven and one-half hours ofreal time data daily.

OSO 5 has been operating successfully in orbit for sixmonths. The spacecraft, including both tape recorders andseven of eight experiments continues satisfactory operation.

OSO-H is scheduled to be launched late in 1970.The OSO program is directed by Physics and Astronomy

Programs, Office of Space Science and Applications, NASA Head-quarters, Washington, D.C. Project management is under theGoddard Space Flight Center, Greenbelt, Md., which is a].loresponsible fo r the tracking and data acquiItion and .heDelta launch vehcle.. Launch of the Delta .I.s supervi ed byKennedy Space Center's Unmanned Launch Operations (ULO).

-more-


9/39

-6-The OSO spacecraft are designed and built by Ball

Brothers Research Corp., Boulder, Colo. The Delta launchvehicle is buil t by McDonnell-Douglas Astronautics Co.,Santa Monica, Calif.

END OF GENERAL RELEASE; BACKGROUND INFORMATION FOLLOWS

-more-


10/39

-7-

OSO: THE ENGINEERING FEATURES

The OSO program pioneered the observatory satelliteconcept. In the process it has achieved a major success forspace astronomy. It has been estimated that each OSO obtainedabout the same amount of information on the Sun as would beobtained from the launch of 12,000 sounding rockets.

The OSO-G spacecraft consists of two major sections:a sail, carrying two pointed experiments which always facethe Sun, and a wheel with three arms which rotates at 30rpm to stabilize the spacecraft. The wheel section carriesfive experiments.The sail, approximately semicircular in shape, is 23inches high and 44 inches wide. It is covered with light-sensitive solar cells to charge the on-board batteries. Thewheel, built of aluminum, is 44 inches in diameter, and at-

tached to the sail section by a bearing lubricated shaft.The wheel section, in addition to the five experiments, car-ries telemetry and other satellite subsystems.Nitrogen gas jets in the three arms maintain the properwheel rotation rate. Since the instruments in the wheel viewthe Sun every two seconds (when the spacecraft is in sunlight)and the rest of the sky at other times, they also are ableto make comparative measurements of solar and spatial phenomena.

Pointing, Scanning CharacteristicsAn important OSO-G first to the program is that it

will have the additional capability to offset point to anyof the 16,384 points on a 128 x 128 point grid pattern. Itwill also be able to perform a 7 x 7.5 arc-minute rasterabout any of these grid points.

OSO I and 030 III could only point directly at thecenter of th e Sun. OSO II, IV and V could point at thecenter of th e Sun and perform a scan across th e solar dioc.OSO-G will have four point and scan modes of operation.In th e first, called th e pointed or oriented mode, th ' sail

experiment instruments are kept pointed to the center of theSun within one arc minute of the solar direction during thespacecraft day.

-more-


11/39

~L

/

8

S/

"

I

,--

-(

-

0

1kkk

-

jr41'wLB

0//

a

q

1mI

l4

/

gS

w

I1

0

[0ur]

LoRLL

RIOY/

[1

8~


12/39

AZ'MUT.3 , 30 40 C

. .. ._ .' o

S --. -----------.3- -- -

4?

'384SF.S- - - ------- -4 - - .--. - ------- -

46 ARC :A, --(7 6t$ SEC

A - POINT OODE8 :OFFSE POINT 7c5 UP EL I VATION 8 ; "R ," AZ ' 24 8'TS ELEVATn',, 8 48 BITS AZ'MUTTH,C MALL RASTER0 LARGE RASTER

-- . - - - - - - - - - - - - . - -


13/39

-8-

In the second, called the offset point mode, the sailexperiment instrument will be pointed to any one of the 16,384intersections on the 128 x 12S grid pattern which is centeredon and covers more than the active solar disc.In the third mode, called the large raster scan, thepointing section will perform a 46 (azimuth) x 46 (elevation)arc minute scan of the solar disc and corona.In the fourth mode, called the offset scan, the pointingsection will lock on to any of the 16,384 points on the gridpattern and perform a 7 (azimuth) x 7.5 (elevation) arc minutescan. The resolution of the large (46 x 46 arc minute) rasteris 64 lines, whereas it is 16 lines for the small (7 x 7.5arc minute) raster. The frame period for the large rastermode is 491.5 seconds (24 MF/line) and 30.72 seconds (6 MF/line)for the small raster.

-more-


14/39

0"0-! RXPERIMiENTSTwo of the 030.-C exn Oriments are located in the sailportion of the spacecraft and are designed to be pointedtoward the Sun. The remaining five experiments are mountedin compartments of the ni-ne-sided rotating wheel section andthey will scan the solar disc every two seconds when thespacecraft is in sunlight.Organizations providing OSO-C 'Fxperinents include theHarvard College Observatory, Rutgers University, th e Univer-sity of Newi Mexico, the University of Bologna (Ttaly), theUniversity Colle!ge London (En~land), the U.S. Naval ResearchLaboratory, and the Los Alamo:; Scientific Laboratories. Indi-vidual experiment descriptions are 1Listed below.Dr. L. Goldberg, Harvard College Observator SolarUltraviolet Spectrometerspectroheljograph. To obtain theultraviolet soect:'um from 300? to 13000 and the spatial dis-ribution of selected wavelengths.R. W. Kreplin, Naval Research LabDratorv -- Solar X-rayspectral, burstand mapping spectrome-ter. To measure solarX-rays in the 0.13 - 27? wavelength region using a variety ofins(ruments, some of which give high spectral. resolution inthe 0.6 - 25 band.Dr. A. L. Rouv. Rutgers University -- Zodiacal LightPolarimeter. Llete-mine the obrLhtn es, polarization, andeliipticity of zodiacal l ight.Dr. H. V.Argo, Los Scientific Laboratories --Solar X-ray Emisslon Line Spectrometers. 5 'bs-erveolar X-raymission lines in the 16 to Ito spectral range.Dr. C. P. Leavitt, Uriverst'yof New Mexic-o -- Hiirgh E'n-ergy Neutron Trelescope. Determine hig Fenergy neutron fluxin the 20 to 130 MieV energy range.Dr. D.Brini., University of Bologni ta l -- 20-200 KeVX-ray Telesope* Observe solar and cosmic X-rays in th e 20 to200 KeV range and nleaS-ure the albedo in this range.Dr. R. L. F. Boyd University Collere. Ljondon England --Solar Ultratiolet Polychrometetyh eT ( eM

(3011), 0 I (833k), 0 fV (790,), and N 111 A eonanceline radiation. (9220)moru


15/39

I

Bt

i

S

I-o0

i

G=

v:

'I

ne

.1

rN

o

?C/"

'.

(

"\

(

0-

-LF

^

*-u

/

P7

-

-0Z:0

-e

~V)1

wl

a

o

E

~

,_

~


16/39

Harvard College ObservatorySolar Ultraviolet Spectrometer-Spectrohel iographPrincipal Investigator: Dr. L. GoldbergObjective: To obtain the uitraviolet spectrumfrom 3000 to 13000 and th e spatialditribuio of selected wavelengths.

II!

Description: Cons/,ts has/l4al, ofa rota7t/5gd// /bo sAt Matspe zeromfere 0oromet/f,/,./e secrometr /ne vr, defz n, 300 l3 ./t; s. /Ane.:otsmMi///'// r~ee/Oi/e 000 racted'/oosl,2,7m ae radfwe- &.: amefs m te sect, of/erSto e/eetr/ ses. Ope/s% mostl /?7&e r'steymode to map Me solar surfac / a/4. selectedwave./Hyt.

POO~B~ Ony HZM


17/39

Si/ University College LondonSolar UV Polychromator\ Principal Investigator: R. L. F. Bovd/ Objective: Study the He I (584A), Ho II (304A),Si11 (8334), O IV (790A), and N Ill(922A) resonance line radiation., ecetran m, t/p/eMt/ lht--"lte* a.. .7e ? dr

SUniversity oo.,Urfologna f e / /11s th

' ^9 20-200 Key X-ray Telescope

Principal Investigator: D. Brini s,1 s

Objective: Observe solar and cosmic X-rays in the

Mered fe CE o20o 20 Ke rang end m easurehe

20-0 albedo in this range.Objective: Observe solar and cosmic X-rs in the20 to 200 Key range and measure thealbedo in this range.Description: Cos,.~tsofas ''m sc,,tYto, detecz'o

t oo &?e 4df 207 N 1o 90*77 a , 1/ 1o tom~ 2OOmei


18/39

Ai

2c

Ec

CcC

*,

0>X

0-8>o

aBl

'i

c

ooa-

>'


19/39

C

\

o

_

,

\

N

U

'

o

1

$

0

E-

r

n

-J

I

I

-

~~~p

r_o


20/39

-10-

THE SUN: BACKGROUND INFORMATION

The Sun is a turbulent, brilliant mass of gases burningwith an intensity far greater than a blast furnace. By astro-nomical standards it is a relatively small star among theestimated one-hundred billion stars that make up our galaxy--one of the hundred million galaxies in the cosmos.As the star closest to Earth, it is of great scientificinterest. If the distance from the Earth to the Sun were8.25 inches, the distance from Earth to the nearest star wouldbe 4.25 miles, and at this scale the Sun would be about the sizeof a pinhead.The Sun is so immense that if the Earth were placed atits center, the Moon would be located slightly over half-wayto its outer edge. Ninety-three million miles--one astro-nomical unit--separate Earth from the Sun. The Sun's raysmust travel eight minutes at the speed of light to reach us.Energy from the Sun is the principal support to lifeon Earth. It literally dominates the solar system with elec-tromagnetic radiations, protons, electrons, other charged parti-cles, and magnetic fields. Scientific investigation of the Sun--restricted until the space age primarily to the limited windowof Earth-bound investigation--is essential to understanding theweather, the behavior of the atmosphere, the ionosphere, and the

influence it exerts over interplanetary space is also essentialfor the advancement of our capabilities in manned space flightand the area of space applications.The OSO program has contributed significantly to man'sknowledge of the Sun/Earth/celestial relaticnship. Instru-ments to study solar activity above the turbulenc, opaque seaof air we know as the Earth's atmosphere, have made possiblefirst-hand, unrestricted solar studies'.

-more-


21/39

-11-

SOLAR GLOSSARY

Age: Estimated 10 billion yearsDiameter: About 864,000 (109 times that of Earth)Volume: 1,300,000 times that of EarthMass: 333,000 times that of EarthSurface Temperature: 1 0 ,30 0 CP(earth, average of 320 F)Interior Temperature: 35 to 50 million degrees F. (earth, 5000oF)Rotation: Varies, more rapid near the equator whereaverage is 24.65 days; in higher latitudesaverage is 35 daysDistance fron, Earth: 93 million miles or 1 Astronomical UnitSpecific Gravity: 1.41 (earth, 5.52)Surface Gravity: 28 (earth, 1)Chromosphere: The rosy red (light pinkish) layer, oratmosphere which extends out severalthousand miles. Visible only duringsolar eclipse because it is over-whelmed by brilliance of the photo-sphere.Corona: The sun's outermost layer visible onlythrough a coronagra-h or during totalsolar eclipse when it appears as avarying white halo against the dnrksilhouette of the Moon. When there arerelatively few sunspots, the corona hasan almost smooth outline. During dis-turbances, however, its streamers canextend outward for millions of miles.Cosmic Ray Particles: Mostly protons with energies rangingfrom less than 10 MeV (rrillion electronvolts) to 50 BeV (billion electron volts).

- more -


22/39

-12-Cosmic Year: The period of time, about 200 million Earth

years, required for the Sun to be carriedcompletely around the center of the MilkyWay galaxy by th e rotation of th e galaxy.Our Sun is just now reaching voting age of21 cosmic years.

Gamma Ray: A quantum of electromagnptic radiation emittedby a nucleus as a result of a quantum tran-sition between two energy levels of the nucleus.Energies range from 100,000 to 1 million elec-tron volts.

Granulations: Usually elliptical in chape and resemblinggrains of rice, they appear over the entire sur-face of the sun. Constantly in motion, theyhave a turbulent life of only a few minutes.

Limb: The edge of the sun's disk, darker than thecenter of the disk.

Penumbra: The grayish-filament-like structures sur-ronding the umbra.

Photosphere: The visible disk of the Sun, diameter 1/20.Plages: The bright or dark calcium clouds that are

found near sunspots. Sometimes called flocculi.The general form for any chromospheric turbine.

Prominences: Geysers of bright hydrogen that come up fromthe surface, or photosphere. Flame-like inappearance they sometimes shoot outward amillion miles. Tne more spectacular seem tobe associated with cui.pots,

Spectrometer: An instrument which measures intensity invarious wavelengths. A dispursing element, suchas a diffraction-gratJ-ig is employed to give thevarious wavelengthso

Sunspots : The dark areas In the photosphere having ex-tremely strong magnetic fields. Apparentlythey are the venting valve for the tremendousforces at work below the photosphere. Some ofthe larger ones have a total area of severalmillion miles. Temperature within a sunspotis believed to be several thousand degrees lessthan that at the surface. The number of sunspotsvaries over a solar cycle of 11.3 years betweenmaximum and minimum sunspot activity.

Umbra: The dark central portion of a sunspot.- more -


23/39

-13-

OSO PROGF:AM SCIENTIFIC RESULTSOSO 1

0SO 1 was launched Mar. 7, 1962. This pioneering observa-tory provided valuable scientic data fo r over 1,000 of its orbits.As the first of the OSO series it clearly established the capa-bility to operate successfully a complex scientific observatoryfor an extended period of time.The contribution of OSO 1 to th e study of active regions iemonstrating that extreme ultraviolet observations carried outover several solar rotations give direct evidence of changingcondit ions in th e corona above an active regi.i.On OSO 1 th e average atmospheric temperature and approxi-mate density of the upper atmosphere between 12 and 248 statutemiles were determined at sunrise and sunset fo r a period of oneweek each of high and low levels of solar activity. The result-obtained by observing th e attenuation of solar spectrum linesfrom 170 to 100 Angstroms with th e Goddard solar spectrometershowed some disagreement with th e dlder models of th e atmosphere.For example, th e difference in temperature between sunrise andsunset was not as much as obtained from th e satellite drag re-ults.In another study, daily values of atmospheric temperaturehave been compared with extreme UV radiaticn data and also withindices of geomagnetic activity. The analysis of both phasesand amplitudes favors th e UV rather than th e solar wind effectas being principally responsible for th e 27-day variations inatmospheric temperature for the months of March and April 1962.Also on OSO 1 a number of "warm" spots which lie belowth e lower Van Allen belt were observed by th e University ofCalifornia Lawrence Radiation Laboratory proton-electron ex-periment. These were observed at th e satellite altitude of357 statute miles between th e latitudes of 33 degrees N and33 degrees S.

OSO 2OSO 2 was launched into orbit on February 3, 1965. Some ofth e major scientific results include:

- more -


24/39

*There are no rapid changes in the brightness of thesky as seen from above the airglow layer. Changes with-in periods of days to weeks of as much as 30 per centare definitely ruled out.*From the standpoint of space astronomy, OSO 2 observa-tions show that the zodiacal light will be the principalcontaminant for orbiting observatories, and that it iscomparable with the sky brightness from the ground, whereboth the airglow and zodiacal light combine to form thebackground.

*There is no appreciable contribution to the zodiacallight from a local (geocentric) cloud of dust.*The majority (at least 80 per cent) of the airglow, asseen in our optical bandwidth of about 4,000 to 6,000Angstroms, arises in the 56 -statute-mile layer.*The airglow shows "meteorological" day-to-day variationsin brightness and color of about one astronomical magni-tude, which seem to be uncorrelated with latitude, long-itude, or time of night.

*The scale of the airglow pattern is very much like thescale of a meteorological system, i.e., of the order of1,000 miles.OSO 3

OSO 3, launched Mar. 8, 1967, has been an outstandingsuccess. Both tape recorders operated satisfactorily fromtime of launch until they failed May 26, 1967 and June 28,1968, respectively. All nine of the experiments operated asdesigned.The Goddard Space Flight Center pointed experiment hadion chambers which monitor at the 2 to 8 Angstrom and 10 to20 Angstrom regions of the solar spectrum; two spectrometerswhich cover the range of about 1 to 4 Angstroms and 8 to 25Angstroms; and a grazing incidence spectrometer which coversthe 20 to 400 Angstrom portion of the spectrum.The grating spectrometer could be stopped on any desiredline and observations made on the changes of intensity in theselected line to give "light curves." The comparison of lightcurves for spectral lines of various elements and of variouslevels of ionization was important in understanding the mechanismof transport of energy through the corona generated by solaractivity. In addition to It:; scientific value, the X-ray datawere forwarded to th e Plare Warning Network of EnvlronmentalScience Services Adminiatrat ion (,ESA. Of particular iIntlerest

- more -


25/39

-- L.5--to scientists h'itv been th e obse-vatJoC; of the' ch!.anft&, inthe ultraviolet spectrum during the soirn.r fres. ''o mo.-erately stronp: new emission l ines have been observed durnrimoderately large flares.

The poirting section also has a scanning spectlro.roterused as a monochromator and provided by hf-e Air Force Cam-bridge Researci Laboratories. This instrument operated suc-cessfully fo r more than six months. it scannea th e solarspectrum from about 250 to 1,3CO Angstroms and orovided solarspectra of th e best reproducibility to date in this regionalthough th e instrument had no spatial resolutjon.In addition to obtaining solar . 'pecra, this experimentmeasured th e atmor:pheric abr-,rptlon of th e solar ultravioletas a function of loItitudl,, :( _ton 'nd hc-ht: i:n te atmo;phc-eThese data are extremely sig:nifIcant for z',.onomy since fromthese absorption spectra th e physical processes occurring inth e upper atmosphere can be studied In detail.The University of Michigan has, in th e wihel sect ion,an ion chamber that measure.3 th e integrated .olar flux from8 to 12 Angstroms. Some interesting variations have beenfound; not all large increases in th e flux correlate wellwith optical and radio observations of solar activit'. Ithas been observed that all optical flares produce X-rays.On th e other hand, out of 42 X-ray events observed before mid-September, 1967, in th e "quick look" data, only 36 were cor-related with optical flares. Also, there is a large range of X-rayenhancements fo r a flare of given importance. In .iddition to I'-research value, this information is also provided t- th e Sn-ceDisturbance Laboratory of th e Environmental cie(ce ,-vVice-,L"ministration.

The University of California at San Diogo has, in thewheel section, a sodium iodide scintillation counter to detectsolar and celestial X-rays from about 7 to 190 iiCovolts. Thisexperiment has produced some Lnteresting aind imror',ant results-for solar physics.

In this .:-, rp;y range th e Sun i& characLer'iz.-z d by itsvariability -.- thl.re exists no "quiet" Sun. Studie have alsobocn made of th e ri.;e time of solar X-ray bursts and of th ecorrelation of th e spectruma with burst activity. The lattershows that th e more intense th e burst , th e harder tlhe X-rays.The Massachuc-etts Institute of Technology has, in th ewheel sect ion, 3 gamma-siay telescope for th e detectiAon of

celestia] gamma-ray sources with energies above 50 Me. t isexperiment requires extremely long observation t imes a r.hetelescooe dete ct, on th e averare about 1 ohoton per Jl'y- fr-nthe sky -nd :ibo,'lf 20 per day from the Enrth. 4s a I'e :u,' theinterpretation of lata from th-s experimenCti- i .s t bogi n.However, one extremely .. i n ficant observ-ition c'0-aaiv ha.:b e mia, -c


26/39

w-------------

-16-

rays of energy greater than 50 MeV. This is important formodels of galactic structure and evolution, and theories onthe energetics of cosmic radiation.The Universit$ of Rochester has, in the wheel section,a particle-counting telescope to study solar and galactic highenergy cosmic ray:. As this experiment also has a very lowcounting rate, it too needs a long lifetime for good statistics.An upper limit to the isotropic flux of hard gamma-rays (energieshigher than 50 MeV) has been determined and is a factor of threelower than the limit determined from earlier observations. Forvery high energy particles the proton (hydrogen nuclei) spectrumseems to be flatter than the alpha particle (helium nuclei) spec-trum. There is an indicrtion that the ratio of hydrogen to heliumincreases with energy for these very energetic nuclei.

OSO 4OSO 4, launched Oct. 18, 1967, carried instrum(.tationfor nine experiments. Poth tape recorders operated satisfact-orily from time of launch until they failed on March 15, 1968and May 12, 1963. All nine of the experiments operated asdesigned.There are three experiments in the pointing section ofOSO 4. A crystal spectrometer provided by the Naval ResearchLaboratory is studying sc.ar X-rays in the 1 to 8 Angstromregion. A scanning spectrometer provided by the Harvard CollegeObservatory was able to scan the solar spectrum in the 300 to1,300 Angstrom region and t,, scan spatially the Sun at fixedwavelengths with spatial resolution elements of about one minuteof arc. The third pointed experiment is an X-ray spectrohelio-graph provided by American Science and Engineering, Inc. Thisexperiment provides "pictures" of th e Sun in wavelengths fromless than 8 to above 70 Angstroms.The Harvard College Observatory ultraviolet spectrohel lo-meter failed and was turned off about Nov. 30, 1967. Over 41,000spectroheliograms of the solar atmosphere between 300 and 1,300Angstroms were obtained. Phese data wil l permit th e develop-ment and assessment of realistic models of the solar atmosphereand wil l provilde insight into th e problem of energy t ransportthrough th e chromo:ophere and corona.Other re.-uLtt from 080 II nclude:* Difference:; have been noted between emissions from a"hot" corona and a relatively low temperature corona.* Significant data on hot .pots in th e solar corona andvaluable spectroheliorams on the "quiet" sun were obtained.

- more -


27/39

-17-* Important data regarding th e density and scale ofheight of th e geocorona were obtained.* Valuable observations on th e distribution of X-rayflux due to flares were made which show the "hardening: ofth e flux caused by solar activity.* Considerable data have been obtained related to part-icle energy spectra for electrons and protons* Spectroheliograms in the lines of various ionic speciesof oxygen, magnesium and hydrogen and in th e continuum. Thesedata represent a major step forward in th e science of solarphysics.

OSO 5OSO $ was launched on January 22, 1969, and was offic-ially classified a success by NASA after achieving its primaryobjectives on February 26. The primary objective of th e eightexperiments of this mission was to obtain high spectral reso-lution data from the pointed experiments within th e range offrom about 1 to 1,250 Angstroms, during solar rotation, includingaster scans of the solar disc in selected wavelengths. Thesecondary objective, also achieved, was to obtain useful datafrom the non-directional experiments as well as from th e pointedexperiments beyond one solar rotation with extended observationsof single lines and solar flares.Status of the individual experiment:; as of July 1969 wasas follows:

X-ray Spectrometer-Goddard Space Flight CenterNow operating only partially, this experiment obta.nshigh spectral resolition data on solar X-ray emission linesin th e range 1 to 400 Angstroms region; observations of th equiet sun have indicated th e presence of emr,sion lines pre-viously undetected. This is due to th e increased sensitivityand reduced background susceptibility of the present instru-ment -ompared with earlier experiments. Enhancements of s;olaremissions have been detected during periods of flare activity,particularly during a class two event observed during orbit159 on Feb. 2, 1969. This instrument has obtained about 2400

high-vesolution spectral scans in the 1-25Angstrom rejlon and800 in the 25-i400 Angstrom region. n- more -


28/39

-1S-

Extreme Ultraviolet Spectroheliograph - U. S. Naval ResearchLaboratory

Approximately 9600 high spatial resolution extreme ultra-violet pictures of th e solar disc at six wavelengths (1216 Ang-stroms, 30 ia ,465 , 284R, 335 , and 499g) have been produced bythis experiment. guring th e flare event of February 2, 1969,enhanced ultraviolet emissions were noted.Solar X-ray Spectroheliograph - Universi ty College London

This instrument is observing th e intensity and variationof th e solar X-ray spectrum in th e 3-9R and 8-186 range andhas obtained about 2100 spectroheliograms. During th e flareevent of Feb. 2, 1969, th e active region of th e solar discshowed flux enhancement by a factor of 50 at 91o The X-rayactive region coincided with a region of enhanced ultravioletemission mapped by th e NRL spectroheliograph.Zodiacal Light Telescopes - Universi ty of Minnesota

This experiment designed to determine th e intensity andpolarization of zodj cal light in th e blue and visual regionshas measured th e intensity of polarized light from th e terrestialairglow layer and has observed stars which have passed in thefield of view of th e telescopes.X-ray Monitor_- U.S. Naval Research Laboratory

This experiment is monitoring th e X-ray energy from th esolar disc in four spectral bands -- 0.5 to 3, 2 to 8R, 8 to16, AND 0.1 to 1.6A. Enhancements associated with changes insolar activity have been observed.Solar Far-Ultraviolet Radiation Monitor - University of Colorado

This experiment is monitoring th e total solar energy fluxin three EUV bands -- 280-3701, 465-630o, and 760-1030p. Todate, ultraviolet absorption measurements have been obtainedat satellite dawn and dusk which will permit determination ofatmospheric gas temperatures.Low Energy Gamm-Ray Scintillation Detector - Goddard Space1_'h t Center

- more -


29/39

This experiment has observed the solar gamma-ray radi-ation ih the 5-150 KeV range. Strong solar bursts of about15 minutes duration were observed durIng th e February 2, 1969olar event.Solar Lyman-Alpha Line Atomic Hydrogen Cell - University ofParis

This experiment is monitoring the 1inechape of thesolar Lyman-alp1ha line using: the optimal r(-s;oriance of hydro-gen and deuterium gases. To date, obs'ervat ions utilizing thredeuterium cell have indicated a broadening of th e line -;hjapecompared with ob.:;ervations made ear:ieor in the so] ar cycle.

- more-


30/39

-20-

THE DELTA LAUNCH VEHICLE

OSO-G will be launched by the Delta launch rocket. Thiswill be the 72nd orbital mission for Delta which has becometh e workhorse for the automated satellite program conductedby NASA.For the OSO mission a two-stage version of the Delta,called Delta N will be used. This incorporates the "long tark"first stage which is 14.42 feet longer than a conventionalDelta first stage. The OSO will be launched from Complex 17at Cape Kennedy, Fla., into a circular 350-mile orbit a t aninclination of 33 degrees and a nominal orbital period of96 minutes.Delta is 106 feet high (including shroud). Its Liftoffweight is about 100 tons. Liftoff thrust is 363,000 pounds,including thrust of three strap-on solid propellant rockets.Delta prime contractor is th e McDonnell Douglas Astronautics Co.,Santa Monica, Calif. The Goddard Space Plight Center, Greenbelt,Md., is responsible for Delta project management.Engines for th e kerosene-liquid oxygen fueled first stageare built by th e Rocketdyne Division, North American RockwellCorp. The three solid rockets which strap on the first stageare by Thiokol Chemical Corp. The UDMH-IRFNA fueled liquidengines of th e second stage are by Aerojet General Corp.The first stage is eight feet in diameter, 65 feet high,weighs 93 tons (including strap ons), and has 172,000 pounds ofthrust. The second stage is 16 feet high, 4.7 feet in diameter,weighs seven tons, and has about 7,800 pounds of thrun:t.Major autopilot contractors for Delta are Honeywell, Inc..Texas Instruments, Inc. and El.ectro-Sollid; Corp. The gu dancecontractor is Western Electric Co.


31/39

S

~Bi

i


32/39

1

--

4

*

H:

E-

I~

0

wo

O,

S

C

00

-

i

0

S

*

*

WU

1(1

I

.-.C

fa*

*

-?

.O

O

-

-

;

O

H-

^&^^

~

~

~'-a

-o

-a

gs

d

Date post:	10-Apr-2018
Category:	Documents
Upload:	bob-andrepont
View:	216 times
Download:	0 times

OSO-G Press Kit

Documents