nasa weather satellite by modestmouse


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                                 A                                      sf
                                  An Educaticsnal Services Publicatisn cr the
                                Nafisnal Aeronautics and Space Adminis#ratisierr
  Vol. I!, No. 12
 (Replaces 8 - 2 - 4 4 )
                                                                            /    Source of Acquisition
                                                                                NASA Contractor/Grantee

                                         The TlROS IX weather satellite.

   Carla      ...
               Donna .     ..
                            Esther ..  . Flora ...         forewarned through information gathered b y
   These were destructive hurricanes which took            meteorological satellites in space, taking pictures
 housands of lives and caused millions of dollars          of the earth's surface and cloud cover. Such
   damage.                                                 warnings have enabled people in the hurricane
   Future counterparts, with other feminine names,         belt to prepare themselves for high winds and
will surely be as severe, but their destructive re-        water, and thus to spare lives and property. Such
sults will be minimized because people will be             was the case with Carla.
Page 2                                                                                                     NASA FACTS Val. lli, No. I 2
   The NASA weather satellite program which                         TlROS I was launched at Cape Canaveral                                j
can detect hurricanes in their formative stages,                 (now Cape Kennedy) on April I , 1960.      Suc-
   d provide a great deal of other information                   cessor TlROS satellites have followed: TlROS II
7 eful to meteorologists i s carried out with TIROS.
This satellite name i s an acronym for Television
                                                                 through IX and Nimbus.
                                                                 Nimbus, Vol. II No. 7.)
                                                                                              (See Nasa Facts,

Infrared Observation Satellite.
                                                                     Operating in a near-circular orbit more than
    Kites, balloon, airplanes and sounding rockets               (400 miles above the earth (apogee, 461 miles,
have been used t o gather weather data from                      perigee, 436 miles) TlROS I made meteorological
varying distances above the earth's surface, with                history by giving meteorologists an unprecedented
results that were effective-sometimes even star-                 opportunity to study the earth's cloud patterns
tling. But TlROS can go higher, stay aloft much                  and relate them to the weather. Among the strik-
longer, and perform tasks never before possible                  ing patterns seen for the first time in their entirety
of accomplishment. TlROS orbits at about 450
miles above the earth, takes i t s pictures with
vidicon (TV) apparatus and transmits them t o
earth for interpretation by meteorologists. In
addition, TlROS has equipment for detecting and
 reporting infrared radiation reflected by the
 earth's atmosphere.

             (Quoted from the NASA publication
            SP-I,Short Glossary o Space Terms)
   ACQUISITION-the          process of locating the orbit of a
   satellite or trajectory of a space probe so that tracking
   or telemetry data can be gathered.        Also, the process
   of pointing an antenna or telescope so that it i s prop-
   erly oriented to allow gathering of tracking or telemetry
   data from a satellite or space probe.
   APOGEE-in        an orbit about the earth, the point at
   which the satellite is farthest from the earth; the high-
   est altitude reached by a sounding rocket.
   AXIS-a     straight line about which a body rotates, or
   around which a plane figure may rotate to produce a
   solid; a line of symmetry.       Also, one of a set of ref-
   erence lines for certain systems of coordinates.
   COMMAND-a           signal which initiates or triggers an
   action in the device which receives the signal.
   ELECTRON-the subatomic particle that possesses the
   smallest known electric charge.
   INFRARED-Infrared radiation; electromagnetic radia-
   tion in the wavelength interval from the red end of the
   visible spectrum on the lower limit to microwaves used
   in radar on the upper limit.
   PERIGEE-that orbital point nearest the earth when the
   earth is the center of attraction.
   READOUT-the action of a radio transmitter transmit-            Artist's concept illustrates TIROS I through Vlll
   ting data either instantaneously with the acquisition of           TlROS has various sensors, or sensing elements, which
   the data or by play of a magnetic tape upon which the              "sense" information and convert i t into signals which
   data have been recorded.
   TELEMETRY-the        science of measuring a quantity or
                                                                      can be measured. These include two TV cameras to                        )
                                                                      photograph cloud cover; a multi-channel scanning radi-
   quantities, transmitting the measured value to a distant           ometer to observe water vapor, night clouds, reflected
   station, and there interpreting, indicating, or recording          sunshine, emitted heat and loud resolution cloud map-
   the quantities measured.                                           ping; and non-scanning radiometers to measure total
                                                                      radiation and thermal radiation.
NASA FACTS Vol. I!, No. 12                                                                             Page 3

   re large-scale cyclones with spiral bands some-             Information from TlROS III in September of
   es covering areas a thousand miles across.               1 96 1 gave warning of Hurricane Carla in time
                                                            to make possible the largest mass evacuation ever
   Photographs transmitted by the satellite's two           to take place in the United States. More than
television cameras also indicated the presence of           350,000 people fled from the path of the storm
jet streams (currents of air blowing at speeds o f          and a relatively small number of deaths was
200 miles an hour or more, at high altitudes) re-           attributable to Carla as i t swept across the
                                                   1        country.
gions of moist and dry air, thunderstorms, weather
fronts, and many types of cloud patterns.
                                                               President Lyndon €3. Johnson, when he was
                                                            Vice President and chairman of the National Aero-
   TlROS I stopped transmitting about midnight
                                                            nautics and Space Council, estimated the follow-
of June 29, 1960, after 1,302 orbits of the earth,
                                                            ing national cost savings, base$ on the accurate
when its power supply failed. It had transmitted
                                                            predictions of weather only five days in advance
22,592 pictures.

                                                               $2.5 billion a year to agriculture.
            HURRICANE DETECTlON                                $45 million to the lumber industry.
                                                               $1 00 million to surface transportation.
   What does early detection of a hurricane mean               $75 million to retail marketing.
in terms of saving lives?                                      $4 billion in water resources management.

                           TlROS Ill HURRICANE DATA
                              ANNA                                          BETSY

            CARLA                                   DEBBIE                               ESTHER

                                      Pictures of hurricanes taken by   TIROS.
Page 4                                                                                NASA FACTS Vol. II, No. 12
                 THE TlROS SYSTEM                                              T V CAMERAS
    The TlROS satellite is a cylindrical, 300-pound,           Two independent television camera systems,
 )-sided polygon resembling a bass drum or an               capable of separate or simultaneous operation,           0
oversized hat box. It stands 22 inches high and             make up the heart of the TlROS satellite. These
measures 42 inches in diameter. Its sides and               cameras are aligned parallel to the satellite's spin
top are covered with more than 9,000 solar cells            axis and extend several inches below the base-
which, when exposed to the sun's rays, produce          {   plate. Each camera system consists of a vidicon
electrical power t o recharge the satellite's 6 3           tube and a focal plane shutter which permits
nickel-cadmium batteries.                                   pictures to be stored temporarily on the tube face
                                                            plate for a brief period.

                                                              Florida during the time of Gordon Cooper's flight in
                                                              Faith 7.

         A diagram of a standard TlROS configuration.

   Protruding from the top of the satellite i s an
 18-inch receiving antenna through which i t re-
ceives commands from ground stations. At the
bottom, four 22-inch transmitting whip antennas
are spaced at 90-degree intervals. Through
these antennas the satellite's transmitters relay
TV pictures, infrared data and telemetry infor-
   tion relating to spacecraft temperature,
    ssure, battery charge levels, spin rate and so
                                                                    The Great Lakes region as seen by TIROS.
    NASA FACTS Vol. II, No. 12                                                                              Page 5

       An electron tube beam converts a stored pic-             tion. These commands set timers in the satellite
    ture into a TV-type electronic signal which is              which activate the camera system when the satel-
    transmitted to a ground station or processed on             lite passes over an area from which cloud cover
    a magnetic tape recorder from which it i s sent t o         pictures are desired.
      arth at a later time, when the satellite i s within
       1,500 mile radius of a Command and Data
    Acquisition station.
                                                                   COMMAND AND DATA ACQUlSlTlON
       Up to 64 pictures-32 on each tape-can be                             STATlONS
    recorded and stored by TlROS during each orbit.
    "Read-out," or sending, which takes about three                Three Command Data Acquisition Stations, the
    minutes, i s accomplished at a ground station by            NASA Wallops Island Station, Wallops Island,
    radio command.       This process automatically             Virginia, the Pacific Missile Range Station, on
    erases the tapes which are then rewound and                 San Nicolas Island, California and the Alaska
    ready for use as the satellite begins another orbit         Station at Fairbanks, Alaska, support the TlROS
    around the world.                                           project. TV pictures from the satellite are flashed
                                                                on special screens and photographed by 35 mm.
       Operation of the cameras, b y direct read-out            cameras at these ground stations. Meteorol-
    or magnetic tape storage techniques, i s based              ogists analyze the photographic data almost
    on radio commands relayed from a ground sta-                immediately.

9                            MOSAIC OF TlROS PHOTOGRAPHS

          WEATHER MAP, M A Y 20, 1960, WITH TlROS CLOUD DATA
Page 6                                                                               NASA FACTS Vol. II, No. 12
                                                               atmosphere. The equipment records data on
                                                               tiny tape recorders for playback on command b y
                                                               a ground station.
                                                                   Since the amount of infrared radiation re
                                                                ceived b y the earth from the sun i s fairly we
                                                                known, the measurements by TlROS of energy
                                                              4 reflected and radiated back into space enable
                                                                scientists to estimate the amount retained to
                                                                produce or affect weather.

                                                                  The infrared observations are transmitted as
                                                               data-not pictures-and must be reduced, ana-
                                                               lyzed, and plotted on maps to be interpreted.
                                                               Hence, they are not useful for operational
                                                               weather observation in the same manner as the
                                                               TV pictures. But they are of great significance
                                                               for scientific studies. Also, the infrared experi-
                                                               ments are part of a continuing program to de-
                                                               velop techniques for data collection for use in
                                                               preparation of infrared nighttime cloud cover
    This antenna at Wallops Island, Virginia, receives sig-
                                                               maps to supplement the daytime TV picture data.
    nals from TIROS.
                                                                             D A T A UTILIZATION

>                 CONTROL CENTER
                                                                  Each of the three TlROS ground stations has
                                                               meteorologists on site as an integral part of the    0
   The TlROS Technical Control Center at the                   station team, responsible for making rapid anal- <.  >,

                                                               yses of the TlROS TV picture.                       ,)
Goddard Space Flight Center, Greenbelt, Mary-
land, monitors operations of the satellite once
                                                                    These analyses are transferred to a map
orbit has been achieved. This Center directs
                                                               chart (nephanalysis) in the form of graphic iden-
the TlROS command and data acquisition net-                    tifications of the cloud elements observed, and
work and monitors the spacecraft and the per-                  transmitted to the National Weather Satellite
formance of the three TlROS Command and Data
                                                               Center via the Goddard Space Flight Center.
Acquisition Stations.
                                                                  The nephanalyses are checked for quality,
                                                               then are redrawn and transmitted to about 600
                                                               recipients in the U.S. They are retransmitted
   In addition to television observations of cloud             from points on the west, east, and southwest
cover, TIROS obtains measurements of infrared                  U.S. coasts, to the Far East, Europe and South
radiation.   This i s invisible heat radiation, or             America.
radiant heat, comprised of rays similar to visible
light, but below the red band of the visible light                                TlROS I X
spectrum.     Instruments for making infrared                     TlROS IX, launched January 22, 1965, pro-
measurements are called radiometers.                           vides complete coverage of the earth compared
                                                               t o the 25 percent coverage provided by earlier
   The infrared detectors carried by TlROS take                TIROS craft. TlROS IX i s the forerunner of the
 eadings to provide information on how the sun's               joint NASA-U.S. Weather Bureau TlROS Opera-          0
energy i s absorbed and reflected by the earth's               tional System (TOS).
NASA FACTS Vol. I!, No. 1 2                                                                                              Page 7

     Several innovations are responsible for the                      line on a tube, built a picture on a screen, and
improvement in coverage made possible by                              then photographed the screen, the APT system
TlROS IX. One i s the location of two cameras                         transmits pictures by a process similar to that
viewing in opposite directions from the satellite's                   used to send radio photographs. These pictures
    rved outer rim. In orbit, TIROS IX i s tilted on                  will appear on facsimile machines as they are
  s curved side so that it resembles a cartwheel                      received.
rolling along an imaginary track.     The cameras
take pictures when they are aimed at earth.                              When this photo system becomes operational
     Another innovation i s the launch of TlROS                       it will provide cloud-cover pictures at relatively
I X into a near-polar, or north-south, orbit. Such                    low-cost to ground stations anywhere in the
an orbit provides global coverage because of                          world, whenever a satellite is within radio range.
the satellite's movement and the earth's rotation.
Earlier TlROS satellites were launched into east-
                                                                         Cost of a typical ground station equipment for
west orbits.     Moreover, the orbit of TlROS IX is
                                                                      the APT system, which consists simply of a receiv-
nearly sun-synchronous. This means that the
                                                                      ing antenna and amplifier, an F receiver and the
 precession, or normal westward drift of the orbit,
                                                                      facsimile recording equipment, i s about $30,000.
 is so paced that the sun i s always behind TlROS
IX during daylight, or northward, passes, thus
 providing ideal photographic lighting conditions.

                                                                         The antenna for the new Automatic Picture Transmission

                                                                                          TIROS LIFETIME

                                                                          Original useful life expectancy of TlROS satel-
                                                                      lites was about three to four months. However,
 Sketch shows how TlROS IX turned on its side to roll through space
                    like a slow-turning wheel.                        all but the first TIROS have exceeded this life
                                                                      span, providing research and development knowl-
                                                                      edge for NASA and cloud-cover photos for use
 AUTOMATIC PICTURE TRANSMISSION (APT)                                 by the U.S. Weather Bureau in daily operations.
   A new "automatic picture transmission" sys-                        TlROS I operated 2'/2 months, TIROS 11, 10
 tem (APT) i s being successfully tested on TlROS                     months, TlROS Ill and IV, 4% months, TIROS V,
                                                                       10'/2 months, TlROS VI, 13 months.      TlROS VII,
                                                                      launched June 19,1963, and TlROS VIII, Decem-
    Unlike the transmission system carried in the                     ber 21, 1963, were still operating when this was
    rly TIROS satellites which displayed each TV                      written.
Page 8                                                                                                     NASA FACTS Vol. I!, No. 12

  TlROS satellites took approximately 300,000                                Islands, just off the westernmost tip of Africa,
photos during the first three years of operation.                            the Caribbean Sea and the Gulf of Mexico.

                                                                                Most of the hurricanes which affect North                       @
                                                                              America occur during the months of August,
                 DELTA LAUNCH VEHICLE
                                                                              September and October.                                            f
   TlROS i s launched by the 90-foot, 57-ton,                                   The highest wind speed observed during a
three-stage Delta booster. The nation's most
                                                                             hurricane was 186 miles per hour recorded in
reliable space booster, Delta scored 21 straight
                                                                             New England in 1938. However, wind damage
launch successes from 1960 to 1963.
                                                                             indicates that speed in excess of 2 0 0 miles per
                                                                             hour have occurred. Winds of 90 and 100
   The Delta first stage i s the DM-21 Thor, a 57-                           milesper hour are fairly common in well-
foot, liquid-fueled rocket which generates ap-                               developed hurricanes.
proximately 170,000 pounds of thrust during its
burning time of two minutes and twenty-five
                                                                                       A Delta launch vehicle at lift off with TIROS.

   The liquid-fueled second stage produces about
7,500 pounds of thrust for 160 seconds. The
TlROS mission calls for Delta to coast for about
six minutes following second stage burnout.

  The Delta third stage i s a solid fuel, 3,000
pound thrust engine, which burns about 40

-      J     ~      ~     ~      ~      ~      ~      .

     Any intense storm originating in the tropics
which has winds of 7 4 miles per hour or stronger
i s considered a hurricane. If the strongest winds
 are less than 74 miles per hour, i t i s called a
tropical storm.

   Although meteorologists don't know iust how
a hurricane is formed it i s believed that large
bodies of warm, moist air are the breeding
grounds for hurricane development. Tropical
oceans near the equator which have these char-
acteristics are the Atlantic near the Cape Verde

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