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RELEASE: 91-72

        The National Oceanic and Atmospheric Administration's NOAA-D
meteorological satellite is scheduled for launch no earlier than
May 14, officials from NOAA and NASA announced.

        Like other NOAA satellites, NOAA-D will collect meteorological
data and transmit the information free of charge directly to users
around the world to enhance local weather analysis and
forecasting.  The users include more than 100 national

        In addition to assisting local weather forecasting, the
satellite data are used for agriculture, fishing, forest
management, flood control, fire detection, volcano emission
detection, vegetation mapping, oceanography and global climate
change research.

        Launch of the 3,127-pound spacecraft is planned for 11:52 a.m.
EDT from Vandenberg Air Force Base, Calif.  To be known as NOAA-12
once it is in orbit, the satellite will be boosted on a U.S. Air
Force Atlas-E launch vehicle into a 450-nautical-mile circular,
near polar, sun-synchronous orbit with an inclination angle of
98.70 degrees to the Equator.  Orbital period will be 101 minutes,
with the spacecraft crossing the Equator at 7:30 p.m. northbound
and 7:30 a.m. southbound, local solar time.

        NOAA-D will carry five primary instruments:  the Advanced Very
High Resolution Radiometer, a radiation detection instrument to
determine cloud cover and surface temperature; the High Resolution
Infrared Radiation Sounder and the Microwave Sounding Unit, which
combine to detect and measure energy from the troposphere to
construct a temperature profile from the surface to an altitude of
about 6 miles.

        Also onboard the spacecraft is the Space Environment Monitor to
measure the population of the Earth's radiation belts and the
particle precipitation phenomena resulting from solar activity,
and the ARGOS/Data Collection System which receives signals from
approximately 2,000 platforms (buoys, balloons and remote weather
stations) and transmits the data to a central processing facility
on the ground.

        Operational ground facilities include Command and Data
Acquisition stations in Fairbanks, Alaska, and Wallops Island,
Va.; the Satellite Operations Control Center and Data Processing
Services Subsystem facilities in Suitland, Md.; and a data
receiving station in Lannion, France.

        The NOAA-D is a TIROS-N (Television Infrared Observation
Satellite) class spacecraft, built by the General Electric Astro
Space Division.  The world's first weather satellite was a TIROS,
launched April 1, 1960.

        The TIROS program is a cooperative effort of NOAA, NASA, the
United Kingdom, Canada and France for providing day and night
environmental and associated data on a daily basis.  NOAA is
responsible for establishing the observational requirements and
for operating the system, and NASA, through its Goddard Space
Flight Center in Greenbelt, Md., is responsible for procuring and
developing the spacecraft and for conducting on-orbit checkout of
the satellite before transferring the system to NOAA for
operational control.  The U.S. Air Force provides launch support
with its Atlas-E launch vehicle, built by General Dynamics Space
Systems Division.

NOAA-D Physical Characteristics

Main body:   12.2 feet (3.71 meters) long; 6.2 feet (1.88 meters)
in diameter.

Solar array:   7.8 by 16.1 feet (2.37 by 4.91 meters)

Weight:   At liftoff 3,127 pounds (1,418 kg); on orbit, 1,620
pounds (735 kg).

Lifetime:   Greater than 2 years.

Orbit:   Circular, altitude 450 nautical miles; inclination, 98.7
degrees; period 101.35 minutes; sun synchronous, crossing the
equator going south at 7:30 a.m. local time and north at 7:30 p.m.

NOAA-D Mission Timeline

Launch Sequence Mission Time (min: sec.)
Launch   11:52 a.m. EDT
Booster Engine Cutoff (BECO)    2:01.3
Booster Package Jettison        2:04.1
Nose Fairing Jettison   2:23.0
Sustainer Engine Cutoff (SECO)  5:21.3
Vernier Engine Cutoff (VECO)    5:40.4
Spacecraft Separation   5:46.4
Solid Motor Ignition    10:23.5
Solid Motor Burnout     11:06.5
Array Deployment        17:35.0
Boom Deployment 21:00.0
Array Cant      23:40.0
Very High Frequency Antenna Deployment  28:10.0
Ultra High Frequency Antenna Deployment 28:30.0
Handover        34:00.0

The ATLAS-E Booster

         Atlas, built by General Dynamics Space Division, San Diego,
Calif., was originally designed as an intercontinental ballistic
missile in the mid 1950s.  The first flight of an Atlas took place
on Dec. 18, 1958.

        The Atlas family of launch vehicles (Atlas E, H, and SLV-3D) are
considered intermediate boosters.  The boosters, stored at Norton
Air Force Base, Calif., are modified for use in the space program.
The modifications include the updating of guidance systems and
improved safety controls.

        The list of payloads boosted by Atlas include Mercury (manned
orbital flights), Ranger, Mariner, Pioneer, INTELSAT, NAVSTAR and
most recently the Combined Release and Radiation Effects

        The Atlas E launch vehicle is 92 feet (27.9 meters) in length
and 10 feet (3.1 meters) in diameter.  It has a gross liftoff
weight of 412,900 pounds (187,310 kilograms).  Burning LO 2 and
RP-1 (liquid oxygen and kerosene-type fuel), the rocket's three
main engines will produce 389,000 to 392,000 pounds (176,450 to
177,811  kilograms) of thrust at liftoff.

Apogee Kick Motor

        The spacecraft will reach its nominal orbit by use of a Morton
Thiokol, Elkton Division, STAR 37S solid propellant motor.  This
37-inch (94-cm) spherical rocket motor, which has flown on all
previous TIROS-N missions to date, provides an average of 9,542
pound-feet of thrust during a 43.5 second burn.  The motor remains
with the spacecraft after the burn.

NOAA-D Instrumentation

        The instrument systems provide both direct readout and onboard
recording and playback of environmental data during day and night
operations.  The primary instruments carried by the NOAA-D
spacecraft are:

        % Advanced Very High Resolution Radiometer/2 (AVHRR/2).
        % High Resolution Infrared Radiation Sounder/2 (HIRS/2).
        % Space Environment Monitor (SEM).
        % Microwave Sounding Unit (MSU).
        % ARGOS Data Collection System (ARGOS/DCS).

Advanced Very High Resolution Radiometer/2

        The AVHRR/2 is a radiation-detection instrument used to remotely
determine cloud cover and the Earth's surface temperature.  The
scanning radiometer uses five detectors that collect different
bands of radiation wavelengths.  Measuring the same view, this
array of diverse wavelengths, after processing, will permit
multispectral analysis for more precisely defining hydrologic,
oceanographic and meteorological parameters.  One channel will
monitor energy in the visible band and another in the near-
infrared portion of the electromagnetic spectrum to observe
vegetation, clouds, lakes, shorelines, snow and ice.

        Comparison of data from these two channels can indicate the
onset of ice and snow melting.  Depending on which instrument is
used, the other two or three channels operate entirely within the
infrared band to detect the heat radiation and temperature of
land, water, sea surfaces and clouds.  Use of two adjacent
frequency bands eliminates the hindrance to determining surface
temperature caused by clouds.

High Resolution Infrared Radiation Sounder/2

        The HIRS/2 detects and measures energy emitted by the atmosphere
to construct a vertical temperature profile from the Earth's
surface to an altitude of about 24 miles (40 km).  Measurements
are made in 20 spectral regions in the infrared band.  One
frequency lies at the high end of the visible range.

Microwave Sounding Unit

        The MSU detects and measures the energy from the troposphere
(the lowest layer of the atmosphere) to construct a vertical
temperature profile to an altitude of about 6 miles (10 km).
Measurements are made by radiometric detection of microwave energy
divided into four frequency channels.  Since its data are not
seriously affected by clouds, the MSU is used in conjunction with
the HIRS/2 to remove measurement ambiguity when clouds are

Space Environment Monitor

        The SEM is a multichannel, charged-particle spectrometer.  It
measures the population of the Earth's radiation belts and the
particle precipitation resulting from solar activity (both of
which contribute to the solar/terrestrial energy interchange).
The SEM consists of two sensors, the total-energy detector and the
medium-energy detector, and a common data processor.  The SEM's
objectives are to determine the energy deposited by solar
particles in the upper atmosphere and provide a solar warning

The ARGOS Data Collection System

        The ARGOS/DCS, provided by France, assists NOAA in its overall
environmental mission and in the support of the Global Atmospheric
Research Program.  Approximately 2,000 platforms (buoys, free-
floating balloons and remote weather stations) measure
temperatures, pressure and altitude, and they transmit these data
to the satellite.  The onboard DCS receives the incoming signal,
measures both the frequency and the relative time of occurrence of
each transmission, and retransmits these data to the central
processing facility.  The DCS information is then sent to the
Centre National d'Etudes Spatiales ARGOS processing center, where
it is processed, distributed and stored on magnetic tape for
archival purposes.  The NOAA-D DCS data rate is 720 bits per

Communications and Data Handling

        The communications subsystem uses eight transmission links to
handle communications between the satellite and ground stations.
The satellite is controlled from NOAA's Satellite Operations
Control Center (SOCC), Suitland, Md.  The ground system is made up
of Data Acquisition and Control Subsystem (DACS) and the central
processing system designated the Data Processing Services
Subsystem (DPSS).

        The primary command and data acquisition (CDA) stations are
located in Fairbanks, Alaska, and Wallops Island, Va.  The CDA
stations transmit command programs to the satellite, acquire and
record meteorological and engineering data from the spacecraft.
Through a cooperative arrangement between NOAA and the
Establissement d'Etudes et de Recherches Meteorologicques in
France, stored and real-time data can be relayed from the Lannion
Centre de Meteorologie Spatiale through NOAA geostationary
satellites.  All data are transmitted between CDA stations and
Suitland through commercial communications links.

        The ground communications links for satellite operations are
provided by SATCOM and NASCOM.  NASCOM provides any launch-unique
communications links for satellite launch.  SATCOM provides all
voice and data links between the SOCC and the CDA stations after
launch.  SATCOM is provided and operated by NOAA's National
Environmental Satellite Data and Information Service (NESDIS).

        DPSS acquires data from the CDA stations through SOCC and is
responsible for the data processing and generation of
meteorological produces on a timely basis to meet program
requirements.  NOAA provides all hardware and software for DPSS.

Summary of Previous NOAA Satellite Missions

        The NOAA satellites are TIROS spacecraft.  The TIROS program is
a cooperative effort of NASA, NOAA, the United Kingdom and France
to provide day and night global environmental and associated data
for operational purposes on a daily basis.  TIROS-N, a research
and development spacecraft serving as a protoflight for the
operational follow-on series, NOAA-A through NOAA-H, was launched
October 13, 1978.  NOAA-A and -C through -H have been designated
NOAA-6 through NOAA-11 after launch.

        % NOAA-A (6) was launched June 27, 1979 and was deactivated on
March 31, 1987.
        % NOAA-B was launched May 29, 1980 but failed to reach a usable
orbit.  Because it failed, it has no number.
        % NOAA-C (7) was launched June 23, 1981 and was deactivated in
June 1986 following a power system failure.
        % NOAA-D was dropped out of sequence in favor of NOAA-E, a
longer spacecraft that could accommodate more instruments,
including search and rescue equipment.  NOAA-D will be designated
NOAA-12 upon successfully reaching orbit.
        % NOAA-E (8) was launched March 28, 1983.  The spacecraft became
non-operational on December 29, 1985 following clock and power
system failures.
        % NOAA-F (9) was launched December 12, 1984.  It currently is on
standby status with some data still being processed.
        % NOAA-G (10) was launched September 17, 1986.  All instruments
and subsystems are performing well except the Earth Radiation
Budget Experiment (ERBE) scanner which has exhibited a scan
sticking anomaly.
        % NOAA-H (11) was launched September 24, 1988.  All instruments
are performing well.  The attitude control subsystem has lost two
of its four gyros and is being operated successfully with
specialized onboard software.

NOAA-D Mission Management

Jennifer Joy Wilson     Assistant Sectretary of Commerce, Oceans and
                        Atmosphere; Deputy Administrator, NOAA.

Gray Castle             Deputy Undersecretray of Commerce, Oceans and

Thomas N. Pyke Jr.      Assistant Administrator, Satellite and Information

NASA Headquarters

Dr. L.A. Fisk           Associate Administrator, Space Science and Applications

Alphonso V. Diaz        Deputy Associate Administrator, Space Science and

Dr. Shelby G. Tilford   Director, Earth Science and Applications Division

James Greaves           Program Manager, NOAA-D

Goddard Space Flight Center

Dr. John M. Klineberg   Director

Dr. Dale W. Harris      Acting Director, Flight Projects

Charles E. Thienel      Project Director, Meteorological Satellites

Dr. Joel Susskind       Project Scientist, Meteorological Satellites

William Peacock         Manager, TIROS Spacecraft

International Partners

Daniel Hernandez        Director, ARGOS and SARSAT programs, CNES

John Morgan             Director, EUMETSAT.

Comments and questions: Jennifer Green
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