Tiros IV Press Kit

8/8/2019 Tiros IV Press Kit

1/9

N EWS R ELEASE- NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

400 MARYLAND AVENUE, SW, WASHINGTON 25, D.C.TELEPHONES: WORTH 2-4155-WORTH 3-1110FOR RELEASE: Sunday AM'sFebruary 4, 1962

Release No. 62-24FOURTHTIROS

METEOROLOGICAL SATELLITE(TELEVISION INFRA-RED OBSERVATION SATELLITE)

The National Aeronautics and Space Administration willsoon attempt to launch and place into orbit the fourth of aseries of seven programmed Tiros meteorological satellites. Theprimary purposes -willbe to further the research on and develop-ment of meteorological satellites, and to obtain data foroperational use in weather forecasting.The continuing research and development activities inProject Tiros are designed to achieve the following:1. Provide the meteorologist with the data which willincrease his understanding of the atmosphere andhis ability to predict weather events;2. Develop the basic principles leading toward anoperating meteorological satellite system;3. Insure the progressive improvement of meteorologicalsensors, spacecraft, and satellite systems througha continuing flight program.With the exception of one television camera lens systemthe satellite will perform much like the previous Tiros satel-lites. If successfully launched, it will circle the earthabout every 99 minutes at an approximate altitude of 400 miles.A camera lens different from any previously used in Tirossatellites has been installed in one of the camera systems forthe purpose of reducing distortion and providing somewhat betterresolution in the picture image while preserving relativelylarge coverage.


2/9

-2-

From an altitude of 475 miles, this lens will cover anarea about 450 miles on a side when the camera is pointingstraight downward.The second camera will have a lens identical to the wideangle cameras used in Tiros Is II and III. This lens coversan area about 750 miles on a side from an altitude of 475 miles

when the camera is pointed straight down.The use of the narrow angle lens carried on Tiros I and IIwas discontinued since more valuable data to the meteorologistwas obtained with the wide angle lenses.As in Tiros I, II and III, the satellite carries twomagnetic tape recorders each of which can store up to thirty-two successive pictures for transmission earthward when thesatellite is within the 1500-mile command range of one of thetwo ground stations.Other instrumentation includes remote control electronics,electronic clocks for triggering the cameras when away fromthe ground stations, beacon transmitters, horizon scanners,telemetry circuits and a magnetic orientation control system.Nearly identical infra-red experiments to those in Tiros IIand III also will be carried by the satellite. These are .used f)in measuring the sun-earth heat-balance radiation relationships.Power for the operation of the electronic equipment isfurnished by nickel-cadmium storage batteries charged by morethan 9,000 solar cells which are mounted. n the top and sides'of the spacecraft. IThe satellite will be boosted into orbit by a three-stageDelta rocket developed by NASA.NASAts Goddard Space Flight Center at Greenbelt, Marylandhas responsibility for overall technical direction of thesatellite, including tracking, command, data acquisition,and the infra-red radiation experiment. The Office ofMeteorological Satellite Activities of the U. S. WeatherBureau is responsible for coordinating the operational use ofthe cloud picture data, and for their research use. OtherU.S. weather services participate in both operational and

research use.

(7


3/9

: II

FACT SHEETTHE TIROS SATELLITE

GENERAL:The satellite was designed to obtain television picturesof cloud formations and infra-red radiation measurements ofatmospheric heat balance over much of the world, and to trans-mit the data from these experiments to ground stations foranalysis and operational and research use.Weight: 285 poundsShapeDimensions:Cylindrical, resembling a large hat box,42 inches in diameter, 19 inches high.Launch: From Atlantic Missile Range, Cape Canaveral1Florida on a three stage Thor Delta vehicle.Orbit: Approximately 400 miles altitude at an in-clination of about 48 degrees from the Equatorat speeds approaching 17,000 miles per hour.

OPERATION:Power: 9,260 solar cells provide electrical energy to63 nickel cadmium storage batteries.Transmitters: Five transmitters relay data from thesatellite to ground stations.

a. Each of the two television camera systemshas a two watt transmitter operating on235 megacycles.b. One two-watt 237.8 megacycle transmitterrelays infra-red experiments data.c. Two tracking beacons operating continuaouslyon frequencies of 136.23 me and 136.92 me areused to relay satellite telemetry data suchas temperature, pressure and battery chargelevel.

Television System: The TV cameras use a one-half inchVidicon tube especially designed for satellite,use. The cameras are aligned parallel to thesatellite!s spin axis and extend through the space-.craft.baoeplate. Each camera consists of'a Vidicon


4/9

1~

-4-tube and a focal plane shutter which permits -still pictures to be temporarily stored ontube face plate. An electron beam convertsthis stored picture into a TV type electronicsignal which can be transmitted to groundstations or stored on a magnetic tape recorder.

In each camera system there is a magnetictape recorder and electronic clock or timer.Over remote parts of the earth each recordercan store up to thirty-two pictures on themagnetic tape for later relay -- this can bedone by programming the timer as much as fivehours in advance. When the satellite is with-in ground station range the photograph signalsare "read out" and the tape is erased and re-wound for the next recording. When the satel-lite is within range of the ground station, therecorder can be bypassed so that pictures canbe directly transmitted. Read outs are there-fore referred to as being either direct orremote.The recording tape is 400 feet long andmoves fifty inches per second during playbackand recording. Photographs are transmittedfrom one camera at a time and complete readout from both cameras takes about three minutes.

Horizon Sensor:An infra-red sensor mounted on the rim ofthe satellite can sense when its field of viewcrosses the Earth's horizon. This informationis relayed to the ground stations via thetracking beacon and assists in determing thesatellite's attitude in space.

North Indicator:Around the sides of the satellite are nineequally positioned solar cells which generatecoded impulses which are used to measure theposition of the satellite with respect to the

Sun. These data are transmitted with the TVtransmission to the ground stations where theyare processed by a sun-angle computer to showwhich direction is North in each photograph.all%


5/9

-5-Magnetic Orientation Control:

A wire coil around the exterior lower sideof the satellite generates a controllable magneticfield around the satellite. When this magneticfield interacts with that of the earth, the coilprovides a means for very gradually tilting thesatellite on command to obtain an advantageousangle for the sensors and the solar power supply.Controls:

When the payload is separated from the thirdstage it will be spinning at about 126 r.p.m.About ten minutes after separation a timer willrelease 'a esnJn mechanism to slow the rotationalspeed to about 12 r.p.m. This mechanism con-sists of two weights attached to cables woundaround the satellite. As the weights unwind, theyslow the rate of spin and when completely unwound,drop off automatically.Tiros must maintain a spin rate of at least9 r.p.m. to remain stable in orbit. When thisminimum is approached a pair of small solid fuelrockets are fired which increases the speed toabout 13 r.p.m. There are five pairs of thesespin-up rockets and each pair can be fired onlyonce.The satellite has an internal arrangement ofsliding weights to cancel any wobbling motion.

INFRARED RADIATION EXPERIMENTS:The satellite will carry three radiation experimentsessentially the same as those in Tiros III. The purpose ofthese experiments is to learn how much solar energy is ab-sorbed and reflected, and how much infra-red radiation isemitted, by the earth and its atmosphere and to develop ameans of determining the nighttime idoud cover of the earth.The scanning experiment includes mapping of reflectedsolar radiation, temperature of the earth'i surface or ofcloud tops, and temperature of an atmosph ?ic level varying

with the amount of water vapor but at an average altitude ofabout 25,000 feet.-One non-scanning experiment will provide gross heatbudget information by measuring reflected solar radiationand emitted long wave radiation from the earth and atmosphere.


6/9

-6-The second non-scanning experiment designed by theUniversity of Wisconsin, will also measure the gross heatbudget but the data although of lower resolution will be morecontinuous since the sensors can view the earth almost allthe time.Data from the infrared experiments are recorded continu-ously on magnetic tape for playback of the last orbit's dataon command from one of the ground stations.

GROUND STATIONS:There are two primary command data readout stations.One, operated under a service contract with RCA, is locatedat NASA's Wallops Station, Wallops Island, Virginia. Theother, operated by the Navy, is located at the Pacific MissileRange, California. A backup station is maintained at RCA'sfacility in Princeton, N.J.At the ground stations, cloud cover pictures will bedisplayed in kinescopes and photographed by 35 mm cameras.

In addition, both photo and infrared data will be recordedon magnetic tapes. Weather Bureau teams at both primarystations will analyze the most immediately useful photographicdata for real time operational use.The infra-red tapes will bemsent to NASA's Goddard SpaceFlight Center for processing and analysis.

LAUNCH VEHICLE

The Delta vehicle used to launch Tiros III has thesecharacteristics:Height: 90 feetMax. Diameter: 8 feetLift-off Weight: A little less than 112,000 pounds

First Stage (Modified Douglas Thor):Fuel: Liquid (LOX and Kerosene)Thrust: About 150,000 poundsBurning Time: 160 seconds 0,)


7/9

Second State (Aerojet General):Fuel: LiquidThrust: About 7,500 poundsBurning Time: 109 seconds

Third Stage (Allegany Ballistics Laboratory X-248):Fuel: SolidThrust: About 3,000 poundsBurning Time: 40 seconds (After 7 minute coast)

Firing Sequence:The first stage falls away on burnout. The second stageignites immediately. The nuae fairing which covers thirdstage and payload is jettisoned after twenty seconds of second

stage burning. The third stage doesn't ignite until sevenminutes of coasting after second stage burnout. Then, thethird stage is spin stablized and the second stage falls away.The third stage reaches an orbital velocity of almost 17,000miles per hour.

TIROS PROJECT PARTICIPANTS

The overall responsibility for the project rests withthe National Aeronautics and Space Administration. Thedevelopment and operational phase of the project is under thedirection of NASA'S Goddard Space Flight Center. Goddard willprepare the command programming which the ground stations willrelay to the satellite. These programs will be based on in-formation from NASA's Computing Center and recommendation ofthe Meteorological Satellite Activities unit of the U. S.Weather Bureau. The radiation experiments were designed andthe data storage and telemetry equipment associated with themwere constructed by Goddard.

With the exception of the infra-red experiments, thesatellite was designed and constructed by the Astro-ElectronicsDivision of RCA, Princeton, New Jersey, under contract to NASA.In addition, RCA was responsible for the special ground stationequipment. Barnes. Engineering Company, Stamford,.Connecticut,under NASA oontraet,;provided radiation detectors. The Uni-versity of Wisconsin, designed one of the IR experiments.


8/9

Douglas Aircraft Company is prime contractor for the |)Delta launch vehicle. In addition, it is responsible forlaunching services, supported by the Air Force Missile TestCenter which operates the Atlantic Missile Range.The Meteorological Satellite Activities unit of the U. S.Weather Bureau is responsible for meteorological analysis andinterpretation of the picture and radiation data. Cooperating

in this phase of the project are the U.S. Navy PhotographicInterpretation Center, the Geophysics Research Directorate ofthe Air Force Cambridge Research Laboratories, the Air ForceAir Weather Service, the Navy Weather Service and universityresearch groups.Officials concerned with the TIROS experiment include:Dr. Morris Tepper, Director of Meteorological Systems,NASA Headquarters.Mr. William G. Stroud, Chief of the Aeronomy and Meteo-

rology Division at Goddard Space Flight Center.Mr. Herbert I. Butler, Associate Chief for Projects,Aeronomy and Meteorology Division at Goddard Space Flight Center.Mr. Robert M. Rados, Tiros Project Manager, NASA's Goddard )Space Flight Center.Mr. Abraham Schnapf, Project Manager for RCA's Astro-Electronics Division..Mr. Davrid Johnson, Acting Director of the Weather Bureau's

.Meteorological Satellite Activities.TIROS I, II & III

SUMMARYTiros I was launched from Cape Canaveral, Florida, April 1,1960. Between launch and June 17, 1960 when operations ceased,the satellite transmitted nearly 23,000 photographs of cloudcover. Despite its relatively brief useful lifetime of 78 days,meteorologists hailed Tiros I experiment as opening a new erain weather observation.Tiros II was launched November 23, 1960, It far exceededits estimated useful lifetime of three months and continuedto provide data through November of 1961. Beyond this achieve-ment, in January 1961 the satellite photographed the tightlypacked ice in the St. Lawrence and in March took rAotographs ( )for several days which showed the breakup of the L- pack.


9/9

-.9-These ice pack photographs were the first and best indicationsthat weather satellites could be used to photograph and showice boundaries and open seas. Tiros II was also used in jaiding forecasters on weather conditions for the suborbitalflight of Astronaut Alan B. Shepard, Jr. last May and thelaunch of Ranger I in July.

Tiros III was launched July 12, 1961 and like the twoprevious Tiros launches it was a perfect operation. The satel-lite further substantiated the feasibility of operationalweather satellites by again proving the data could be used ona real-time basis for daily weather analysis. It marked thefirst time a weather satellite was relied upon as the solesource of information for the basis of a tropical storm fore-cast. By July 20 Tiros III was providing operational dataon Hurricane Anna and it subsequently photographed HurricaneEsther two days prior to conventional methods which resultedin additional warning time. Operational utilization of thesatellite data was discontinued in late November of 1961 dueto loss of adequate contrast in the picture.

-End-

-I

(

Documents

Tiros IV Press Kit