earth resources technology satellites a (erts-a) press kit

8/8/2019 Earth Resources Technology Satellites a (ERTS-A) Press Kit

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PRESSKIT

NATIONAL AERONAUTICS ANDSPACE ADMINISTRATIONWashington, D. C. 20546202-755-8370

F O R R E L E A S E :THURSDAY,July 20, 1972P R O J E C T : ERTS-A

contentsGENERAL RELEASE 1-13ERTS-A FACT SHEET 14-18DEPARTMENT OF THE INTERIORGEOLOGICAL SURVEY 19-20DEPARTMENT OF COMMERCE 21DEPARTMENT OF AGRICULTURE 22-23ARMY ENGINEERS 24-25ENVIRONMENTAL PROTECTION AGENCY 26REMOTE SENSING 27-28ERTS-A SPACECRAFT 29-31

Structure and Thermal Subsystem. ... 30Power Subsystem 30-31Attitude and Control Subsystem .... 31

THE SENSORS 32-41First Band 32Second Band 33Third and Fourth Bands 33, 36Return Beam Vidicon Subsystem 36-37Multispectral Scanner Subsystem. . . . 40-41

(NASA-TH-X-68489) EARTH RESOURCESTECHNOLOGY SATELLITES A (EBTS-A): PRESSKIT (NASA) 20 Jul. 1972 99 p CSCL 22B

N72-26811

Onclas63/31 33309


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TABLE OF CONTENTS (Continued)

DATA COLLECTION SYSTEM 42-45Wide Band Video Tape Recorder 43-44

GROUND DATA HANDLING SYSTEM 46-47Operations Control Center 46The NASA Data Processing Facility . . . 46-47

NDPF SUBSYSTEMS 48-50Initial Image Generating Subsystem. . . 48Scene Correcting Subsystem 48-49Digital Subsystems 49User Services 49

SCIENTIFIC DISCIPLINE AREAS OF ERTS-AINVESTIGATIONS 51-54Agriculture 51-53Forestry 53-54Oceanography 55-56Geology 57-59Hydrology 60-61Geography, Cartography and Demography . 62-64Environmental Quality/Ecology 65-67Meteorology 68-70

THE DELTA LAUNCH VEHICLE 70-72MAJOR DELTA 89/ERTS-A FLIGHT EVENTS 73ERTS-A PROJECT OFFICIALS 74-77ERTS-A MAJOR CONTRACTORS 78-83ERTS-A PRINCIPAL INVESTIGATORS 84-96

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Joseph J. McRoberts(Phone: 202/755-3680)James Lynch (GSFC)(Phone: 301/982-5565)RELEASE NO: 72-137

NATIONAL AERONAUTICS ANDSPACE ADMINISTRATIONWashington, D. C. 20546Phone: (202) 755-8370

F OR RELEASE:THURSDAY,July 20, 1972

ENVIRONMENTAL AND EARTH RESOURCES SATELLITE TO BE LAUNCHED

A major step will /be taken toward the establishment ofa comprehensive information base about the Earth's resourcesand its surface environment with the launch of the firstEarth Resources Technology Satellite (ERTS-A).

NASA is scheduled to launch ERTS-A (ERTS-1 in orbit)aboard a two-stage Delta rocket from the Western Test Range,Lompoc, Calif., no earlier than July 21.

The 891-kilogram (1,965-pound) ERTS-A will not only bea first step in the merger of space and remote sensing tech-nology to more efficiently manage the Earth's resources, butit will greatly aid in assessing and understanding the changestaking place in our environment.

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i While this is an experimental mission, many use-orientedorganizations believe that experiments of this type willlead to operational systems which will benefit all of mankind.

Charles W. Mathews, NASA's Associate Administrator forApplications, commented, "The environment and resources ofthe Earth's atmosphere, its continents, its coastal shelves,and its oceans, seas, and lakes have rightly become of greatconcern to people everywhere. This concern is in recogni-tion of the closed ecology and finite resources of spaceshipEarth, just as in the spaceships we build.

"In one sense, the world has become small with complexinteractions between activities of nations, continents andhemispheres. In another sense, the world is still large,involving tens of billions of acres of land area and withoceans many times larger. We know humans have impacted muchof this immense area, but how do we establish a baselineand how do we measure changes and differentiate between man-caused and natural changes? To accomplish this end, largeamounts of data must be sensed and gathered from the variousregions of the world in many cases, on a global basis."

The butterfly shaped observatory flying in a 920-kilo-meter (570-mile) circular, near-polar orbit will carry imagingsystems which will provide data that could produce breakthroughsin the efficiency of user-oriented activities in agriculture,forestry, geology, geography (land use management), hydrology,pollution control, oceanography, meteorology, and ecology.

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To carry out the research required to evaluate satel-lite techniques for resources survey and management, NASA isworking with user agencies including the Departments ofAgriculture, Commerce, Interior, the Environmental ProtectionAgency, and the U.S. Army Corps of Engineers, as well asregional state and local organizations.

In addition to the domestic programs, extensive coopera-tive Earth resources projects have been established withCanada, Brazil and Mexico involving ERTS and NASA Earthobservations aircraft.

There are some 300 investigators from 43 states, theDistrict of Columbia and 31 other foreign nations and twointernational organizations expected to participate in thisprogram. NASA and the other government agencies fund thedomestic investigations while the non-domestic investiga-tions are funded by the foreign nations involved.

To handle this large group of investigators, NASA hasassigned 25 specialists to help organize results submitted

by each investigator.Unlike previous unmanned programs where a principal

investigator had his own instrumentation aboard the space-craft and was responsible for analyses of resulting data,all investigators have access to all data from the ERTSinstruments.

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The main purpose of this first mission is to demonstratethe usefulness of remote sensing of conditions on the Earth'ssurface on a global scale and on a repetitive basis. Theseconditions are of economic, social and cultural interest tohumanity.

In broad terms, the ERTS-A objectives are:1. Determine those natural and cultural resource and

environmental data which can be acquired best from spacecraft.'2. Test and demonstrate a combination of data acquisi-

tion procedures and interpretive techniques for applicationof the data in discipline areas such as agriculture, forestry,geology, geography, hydrology, oceanography, and ecology.

.3. Determine how repetitive, synoptic, multispectralobservations by spaceborne instruments can be of economicor social value to commercial, scientific, and governmentalinterests.

Ultimately, ERTS-A and planned follow-on systems areexpected to provide widespread benefits in such areas as:

** Agriculture Information gathered will aid inland use planning, range management, identification and com-batting of crop diseases and improved .irrigation planning.

** Geology -- Information for use in the study of glaciersand volcanoes, earthquake fault systems, and in identifyingterrain features associated with oil and mineral deposits.

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** Hydrology Information for use in detecting waterpollution trends; providing an inventory of surface water inlakes, reservoirs, and rivers; determining snow levels; andmeasurement of factors needed to predict the potential offloods and the location of water reserves.

** Oceanography Observation of environmental sea sur-face conditions which can be related to fish location, sourcesof pollution, behavior of major ocean currents, changes inshorelines and shores due to storms. Maritime commerce canbenefit from better charting of sea conditions, ice fieldobservation and iceberg warnings.

** Geography ERTS data can be used to produce aconstantly updated map showing the various changes in theEarth's surface, natural and man-made, of interest to suchgroups as urban planners and the transportation industry.

During the ERTS-A mission, much of the early imageanalysis will be devoted to obtaining sequential informationor "signatures" on surface features such as vegetation. soiland water.

All objects, living or inanimate, absorb, transmit orreflect visible and invisible lightwaves. All energy comingto Earth from the Sun is either reflected, transmitted, orabsorbed by objects on Earth, each in its own way.

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Sensing in a variety of wavelengths increases thepossibility of identification of every feature in a particu-lar area. The greater the number of spectral bands used themore complete and reliable becomes the identifying responsepattern radiated by each individual resource. This radiationpattern is referred to as a "spectral signature."

To many in the scientific community, especially thoseconcerned with ecology, the ERTS-A launch is one of the mostwidely anticipated events of the space age. Dr. Robert N.Colwell, Associate Director, Space Sciences Laboratory,University of California, Berkeley, an ERTS-A investigatorand expert on remote sensing of agricultural, forestand range resources, earlier this year told the Committeeon Science and Astronautics, House of Representatives:

"Agriculturists, foresters and range managers deal pri-marily with renewable natural resources, including agricul-tural crops, timber, forage and livestock. If such resourcesare wisely managed they can provide mankind with a sustainedyield of food and fiber not merely for a few generations tocome but perhaps, as some resource managers claim, 'inperpetuity1. If however, these resources are not managedwisely, man's very survival may soon be threated."

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The spacecraft's sensors, along with their associatedcommunications and electronic equipment, weigh 220 kilo-grams (485 pounds).

Onboard instrumentation includes:-- Return Beam Vidicon Television Cameras (RBV).

These three cameras will view the same 185 by 185 kilometers(115 by 115 miles) square area in three different spectralbands, the green, red and near infrared portion of the spec-trum.

Multispectral Scanner Subsystem (MSS). The MSS willreturn images in four spectral bands, the green, red and twonear infrared bands. It will cover a continuous video stripcorresponding to the RBV coverage.

Data Collection System (DCS). The DCS will collectinformation from some 150 remote, unattended instrumentedground platforms and relay the information to NASA groundstations for delivery to the user. The ground platformswill monitor such things as stream flow, snow depth, soilmoisture and volcanic activity.

Wideband tape recorders. The two Wide Band VideoTape Recorders (WBVTR), will be able to record data in theform of images from areas outside of the area of directdata reception in North America for later playback to U.S.ground stations.

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The three main tracking and data acquisition facilitieswhich can receive video information from ERTS are at Fairbanks,Alaska; Goldstone, California and GreenbeIt, Maryland. Canadahas a ground data acquisition station for ERTS at PrinceAlbert, Saskatchewan and data processing facilities in Ottawa.

The spacecraft will be controlled from an OperationsCenter at NASA's Goddard Space Flight Center, Greenbelt.Data received from the satellite at the three data acquisi-tion facilities will be sent to the NASA Data ProcessingFacility (NDPF) at Goddard. NDPF can handle some 1,300scenes a week covering 45 million square kilometers (17million square miles).

Data will be distributed in the form of high qualityfilm images or digitized data on computer-readable magnetictape. Information from the data collection platforms willbe in digital form.

Copies of the data and photos processed at Goddardwill be forwarded to the Department of Interior's Earth

Resources Observation Systems (EROS) Data Center at SiouxFalls, South Dakota. On receipt at Sioux Falls the dataare in the public domain and copies can be purchased byanyone. The Department of Commerce will also have dataavailable at its National Oceanic and Atmospheric Administra-tion (NOAA) Center at Suitland, Md.

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The U.S. Army Corps of Engineers will conduct sevenexperimental projects to test the feasibility of collectingwater resources information by satellite.

Corps experts hope to obtain information and data onsnow cover, precipitation, stream flow, sediment transporteutrophication, beach erosion, changes in vegetation, waterquality, detection of chemicals and solids, drainage andgeneral characteristics of selected waterways.

Experimental projects are in New England river basins,Chesapeake Bay, coastal areas of the Pacific Ocean in Calif-ornia, Cook Inlet area, Alaska, North Carolina barrier islands,Lower Mississippi Valley and a proposed reservoir site inIllinois.

The U.S. Department of Agriculture expects its partici-pation in the experimental ERTS-Satellite to identify areaswhere remote sensing could significantly benefit agricultureand related natural resources.

This would involve testing the practicality of includingspace-acquired data with other data to inventory and makepredictions of the food and fiber resources of the nation,to evaluate the productivity of the land and to monitorchanges affecting the quantity of production or quality offood and fiber.

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- 12 -The remotely sensed data is expected to permit identi-

fication of major agricultural crop types and forest species,insect damage, crop disease, soil salinity and moisturedifferences, mapping of surface water, snowpack, soil andwater temperatures and changes in land use.

Other organizations working with NASA on the ERTSprogram include the Environmental Protection Agency as wellas state and local governments, industry, universities, andforeign governments.

Overall ERTS program responsibility for NASA rests withthe Office of Applications, Earth Observations Programs,Washington,

Project management for the ERTS spacecraft, the Delta

launch vehicle, the Ground Data Handling System (GDHS) andthe world-wide tracking network rests with the GoddardSpace Flight Center, Greenbelt, Md.

Launching of the Delta is supervised by the KennedySpace Center's Unmanned Launch Operations team.

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Prime contractor for the ERTS spacecraft, the data col-lection system aboard the spacecraft, as well as the GroundData Handling System at Goddard is the General ElectricCompany, Space Division, Valley Forge, Pennsylvania. HughesAircraft Company, Culver City, California is prime contractorfor the multi-spectral scanner and RCA, Astro-ElectronicsDivision, Princeton, New Jersey, is prime contractor forthe return beam vidicon camera. RCA, Government and Commer-cial Systems Division, Camden, N.J., is prime contractor forthe wide-band video tape recorders. The McDonnell DouglasAstronautics Company, Huntington Beach, Calif., is primecontractor for the Delta launch vehicle.

NASA costs for the ERTS program are $174 million. Thisincludes two spacecraft, $28 million for the data handlingfacility at Goddard and $34 million for investigations. Inaddition, the Delta launch vehicle for ERTS-A costs $4.2 mil-lion.

(END OF GENERAL NEWS RELEASE; BACKGROUND INFORMATION FOLLOWS)


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- 14 -ERTS-A FACT SHEET

Launch Information:DateLaunch WindowLaunch VehicleLaunch Pad

Orbital Elements:CircularPeriodInclination

Spacecraft:

Stabilization Subsystem:

Mission Objectives:

No earlier than July 21, 1972Opens at 10:54 AM PDT; closesabout 30 minutes later.Two stage Delta, Model 0900SLC-2 West, Western Test Range

920 kilometers (570 statutemiles)103.2 minutesNearly polar, sun-synchronous,inclined 80.9 degrees retro-grade to the Equator.Butterfly shaped, 3 meters(10 feet) tall, 3.4 meters(11 feet) wide (with solarpaddles unfolded) weighing891 kilograms (1,965 pounds).Sensors and electronics arehoused inside a 1.5-meter(5-foot) diameter sensory ring.Earth oriented and threeaxes stabilized to less than0.7 degrees, w/rates lessthan 0.4 sec exclusive oforbital rate.Define those practical Earthresources management problemswhere space technology canmake beneficial contributions;conduct research on sensorsand establish their utilitiesin Earth observation; anddevelop handling and processingtechniques for Earth resourcessurvey.

Spacecraft Designed Lifetime: One year.- more -

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ERTS-A Sensors:Multispectral ScannerSubsystem (MSS)

Return Beam VidiconSubsystem TRBV)

Data Collection System

The MSS will collect data bycontinually scanning the grounddirectly beneath the observa-tory. The width of the stripwill be identical to the cover-age of the Return Beam VidiconCamera, 185 kilometers. Opticalenergy will be sensed by anarray of detectors in fourspectral bands, two in thevisible spectrum and twoin the near infrared part ofthe spectrum.Three 4,125 line RBV cameraswill view the same 185 kilo-meters swath as the MSS.Cameras will be reshutteredsimultaneously every 25seconds to produce 185 x 185kilometers overlapping imagesof the ground along the direc-tion of the satellite motion.The RBV will photograph twobands in the visible and onein the near infrared.Remote platforms for measuringsoil, water and air, qualityand other environmental data,and transmitting the data toERTS as it passes overhead.This system can be expanded toglobal coverage by incorporatingadditional remote receiving sites,This system will provide in-situmeasurements to be used toassist in the interpretationof data from the other twosensors.

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Wide Band Video TapeRecorder (WBVTR)

Tracking:Orbit

Data AcquisitionFacilities

Program Management:

Project Management:

Prime Spacecraft Contractor:

Prime Launch VehicleContractor:Prime Sensor Contractors:

Data Collection System

ERTS-A will not be within rangeof one of the three ground sta-tions , much of the time, so a taperecorder system is required tostore images for later playback.ERTS-A has two WBVTRs and twotransmitters. The system canrecord both sensors simultaneouslyand can transmit two channels ofwideband data at once. The WBVTRhas a digital bit rate of 15 millionbits per second and aQstoragecapability of 3 x 10 . Thenormal tape recorder used in spaceemploys a tape head speed of30 inches per second while theWBVTR has a head and tape speedof 2,000 inches per second.

Stations of NASA's world-wideSpaceflight Tracking & DataNetwork (STDNTFairbanks^, Alaska; Goldstone,Calif.; and Goddard Space FlightCenter, Greenbelt, Md; PrinceAlbert, Sasketchewan, Canada.Office of Applications, NASAHeadquarters, Washington, D.C.NASA/Goddard Space Flight Center,Greenbelt,' Md.General Electric CompanyValley Forge, Pa.McDonnell Douglas AstronauticsCompany, Huntington Beach, Calif.

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Multispectral ScannerSubsystemReturn Beam VidiconCamera Subsystem

Wide Band Video TapeRecorderPrincipal Investigators

Hughes Aircraft Company, CulverCity, Calif.RCA Astro-Electronics Division,Princeton, N.J.RCA Government & CommericalSystems Division, Camden, N.J.300 from 43 states, the Districtof Columbia and 34 foreign countries

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DEPARTMENT OF THE INTERIOR - GEOLOGICAL SURVEYEROS AND ERTS

In preparation for the data to be acquired by ERTS-A,the Department of the Interior has, since 1964, been doingresearch in testing the applications of a broad spectrumof remote-sensing data from aircraft and spacecraft toDepartmental programs.Results of early studies in the basic fields of carto-graphy, geography, geology, and hydrology, were sufficientlyencouraging that in 1966, the Secretary of the Interiorestablished the EROS (Earth Resources Observation Systems)

program as a departmental effort under the management of theU.S. Geological Survey.Through its EROS program, the Interior Department repre-sents the largest single recipient and user agency of datato be.obtained from NASA aircraft and spacecraft designed togather repetitive information related to a wide variety ofEarth science and natural resource disciplines.Resources inventory and management applications have sincebecome an important part of the research program with parti-cipation by 10 bureaus of the Department: the Geological

Survey, Bureau of Indian Affairs, Bureau of Land Management,Bureau of Mines, Bureau of Outdoor Recreation, Bureau ofReclamation, Bureau of Sport Fisheries and Wildlife,, theBonneville Power Administration, National Park Service, andthe Office of Trust Territories.The EROS program has submitted 70 experiment proposalsto NASA to evaluate the applications and use data from theERTS-A satellite. Of these, 40 have been accepted by NASAfor participation in the experimental program. The proposedinvestigations are categorized into five areas of researchthat correspond to working groups of the EROS program:* Cartographic Applications and Mapping Requirements;* Geology, Mineral, and Land Resources;* Water Resources;* Marine Resources; and* Geography, Human, and Cultural Resources.

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- 20 -As part of gearing up for making the best possible inter-pretations and uses of data much of which will be obtainedfrom a variety of remote sensing devices, such as infrared,ultraviolet, and radar devices carried in the satellites the U.S. Geological Survey will manage the EROS Data Center,being constructed at Sioux Falls, South Dakota. Processed

data on terrain features will be stored in retrievable andreproducible form at the Center.

ErosThe $5 million facility, designated the EROS (Earth Re-sources Observation Systems) Data Center, will be constructedon a 315-acre site about 12 miles north and east of Sioux Falls.When completed in the spring of 1973, the Center willbe a key installation as a national central repository for

processing, interpretation, and dissemination of thousands ofimages per year of a wide variety of land and water featuresof the United States obtained from aerial photography and space-borne television and other remote sensing equipment.Principal source of data to be stored at the Center willbe NASA's ERTS (Earth Resources Technology Satellite) satellites.The EROS Data Center will be a one-story steel framestructure with facilities, and will contain about 116,000gross square feet of floor space, designed to house photo-graphic and reproduction equipment and, in addition, specialpurpose hardware for picture rectification and color negativegeneration. During the ERTS experiments, space data will bedelivered to the Center from NASA's Goddard Space FlightCenter, Greenbelt, Md.The facility, according to plans and specifications ofthe. U.S. government, will be constructed by the Sioux FallsDevelopment Foundation, Inc., a nonprofit organization ofSioux Falls businessmen which donated the site. Constructionwill be under a 20-year lease agreement with an option for

the United States to purchase at any time within the period.If the option is not exercised, the facility will become theproperty of the Federal government at the end of the 20-yearperiod.

The EROS Data Center, designed by Spitznagel Partners, Inc.in joint venture with Fritzel, Kroeger, Griffin, and Berg, bothof Sioux Falls, is being constructed by Lueder Contruction ofOmaha, Nebraska, with construction and permanent financingby the First National Bank, St. Paul, Minnesota.

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DEPARTMENT OF COMMERCE

The Department of Commerce (USDC), through the NationalOceanic and Atmospheric Administration (NOAA), is responsiblefor developing and executing programs to assure that the oceanenvironment and its resources are wisely used in a balancedway to enable their development as well as conservation for thenational economic and environmental well-being. NOAA is alsocharged with developing and operating systems to monitor andpredict environmental conditions such as weather, ocean, Earthand solar events, and with exploring the feasibility of bene-ficial modification of environmental conditions and understandingthe consequences of inadvertent environmental modification.Through the Bureau of the Census, USDC is also responsiblefor providing a continuous statistical profile of the popu-lation of the Nation,- measuring significant social and economicdevelopments in each geographical area. Fulfilling these essen-tial public functions requires a very large amount of data ofmany sorts over wide geographical areas, including globaldata in some cases. To meet these objectives, USDC is evaluatingthe feasibility and cost effectiveness of various types of in-situand remote sensing techniques. The Earth Resources SurveyProgram will make an important contribution to this effort,offering an opportunity to evaluate the use of repetitive,multi-spectral observations from aircraft and satellites,together with associated data processing techniques, for thispurpose. While many potential applications would require theavailability of data in near real-time for operational purposes,the current program, while lacking that capability, willpermit research on feasibility and cost effectiveness to bedone and contribute to the design of future operational systems.

In addition to attempting to meet its own mission objectives,USDC will operate an ERS Data Center at Suitland, Maryland, tomeet the needs of secondary users, including the public, inthe disciplines of oceanography, hydrology, and meteorology.- more -


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DEPARTMENT OF AGRICULTURE

The U.S. Department of Agriculture looks to remote sensingas a very necessary and welcome tool in the intensifying waragainst waste. Remote sensing can help save time, save man-power and save resources.

Sensors now detect the subtlest of stresses in livingplants and accordingly have a great potential value for iden-tifying stress in the environment -- crops, forests and range.Such identification will, in some situations, like pest con-trol efforts, lead to corrective action.Corrective action may not be practical or possible inother instances, but the information gained by remote sensing

can be used as a factor in crop estimates and forecasts. Theinformation is essential to production, resource and inventorymanagement.As the world population increases, demands upon the capacityof exporting nations to produce more will become heavier.It will be increasingly important that available resourcesare managed with the least possible waste.Local, state, national and global data, on a nearly real-time basis, would be of great usefulness in making reliableproduction forecasts. Such forecast information, translated

into acres, pounds and bushels, would be of obvious value inreproduction, resource and inventory management decisions and thedesign of sound production adjustment, price support andenvironmental programs involving billions of dollars annually.The related merchandising and transportation industries vitallyconcerned with the availability, location and movement offood, fiber and materials, can benefit from early decisionsbased upon timely and accurate information.Decisions of management of soil, forest, water, range andcropland and on management of commodity inventories will bebetter because they will be based on more accurate and more

current information.Specifically, USDA expects remote sensing to develop as anadditional resource for estimating acreage and production ofvarious crops and possibly for livestock inventories; inventoryof forest resources, classifying and delineating commerialforest land; forest land; forest fire command and control; landuse classification; soil type mapping; detection of water andair pollution; soil and water conservation, including moni-toring snow accumulation and making water supply forecasts.

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USDA will handle the imagery requirements of its own agenciesthrough the facilities of its Western Aerial Photography Labora-tory at Salt Lake City, where it will be reproduced and distri-buted to USDA users.

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- 24 -ARMY ENGINEERS

The U.S. Army Corps of Engineers will conduct seven experi-mental projects to test the feasibility of collecting waterresources information by utilizing the Earth ResourcesTechnology Satellite, the Office, Chief of Engineers announced.

Corps of Engineers experts hope to obtain information anddata on snow cover, precipitation stream flow, sediment trans-port,' eutrophication, beach erosion, changes in vegetation,water quality, detection of chemicals and solids, drainageand general characteristics of selected waterways.Two imaging systems a television camera called aReturn Beam Vidicon and a Multispectral Scanner and a datarelay system aboard the Satellite are expected to provide

multispectral imagery and data which the Corps will use inperformance of its water resource mission. Corps investiga-tors will use surface measurements together with high,medium, and low altitude aircraft remote sensing informationto aid in the interpretation of the satellite imagery.The experimental projects will provide data and imageryof the New England river basins areas, Chesapeake Bay, alongthe coastal areas of the Pacific Ocean in California, in theCook Inlet area in Alaska, the barrier islands off NorthCarolina, the Lower Mississippi Valley and at the site of aproposed Corps reservoir in Illinois.In the New England experiment, 25 data collection plat-forms will be placed along waterways from Stamford, Conn., toFort Kent in northern Maine. The platforms will collect datasuch as stream flow, precipitation, temperature, soil moisture,

tide changes, snow depth and water quality. This will betransmitted twice a day to the satellite's data collectionsystem which will relay it to a receiving computer at theGoddard Space Flight Center in Beltsville, Md. An inter-facing computer at the New England Engineer Division atWaltham, Mass., will receive the relayed data almost simul-taneously. This experiment will test the feasibility of usingsatellite data relay in lieu of expensive "hard wire" or micro-wave data collection systems.

It is anticipated that the Chesapeake Bay studies, whichwill be conducted by the Corps' Waterways Experiment Station,Vicksburg, Miss., will provide information on how seasonalchanges affect the water as river water mixes with the bay,changes in vegetation that occur, sediment movement, detection ofsolids and other foreign matter including chemicals, and otherecological changes in the area.

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- 25 -The Corps will also coordinate 11 investigations in theChesapeake Bay area which are to be conducted by six agencies.The Corps will organize the aircraft remote sensing of the areaand the collection of ground truth and enhance the flow ofinformation among the investigators.In the other experiments:The Cold Regions Research and Engineering Laboratory,Hanover, N.H., will study ice cover, circulation patterns andsediment transport in Cook Inlet in Southern Alaska, and theeffects of steam rings and permafrost changes in the Fairbanksand Eagle Summit areas in central Alaska.The Coastal Engineering Research Center, Washington, D.C.will study beach buildup and erosion as well as dune patternsof the Barrier Islands off North Carolina's Atlantic Coast.The Waterways Experiment Station will have a second projectin the Lower Mississippi Valley to study drainage and vegeta-tion characteristics and to obtain data for flood plain mapping.The South Pacific Division, Corps of Engineer, plans tomonitor coastal processes around San Fransisco Bay, HumboltBay, and the southern California coast from Morro Bay to Mis-sion Bay. It will study sediment transport, estuarineexchange the changes in the estuary where the rivers dis-charge into the bay and the dispersion of chemical andbiological wastes dumped into the water flowing into the bay

and the bay itself.The Construction Engineering Research Laboratory, which is

located near the campus at the University of Illinois, Champaign-Urbana, will evaluate the feasibility of monitoring the environ-mental impact and vegetation changes resulting from construc-tion, filling, and operation of the Oakley Reservoir on theSangamon River in Illinois.- more -


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- 26 -ENVIRONMENTAL PROTECTION AGENCY

The Environmental Protection Agency will participatein joint research programs with the University of Michiganand the Bendix Corporation to detect pollutants and monitorthe general environment using ERTS data. The planned studieswill employ low altitude aircraft, surface observations andmeasurements for verification purposes, and data from theERTS system itself. Each study seeks to determine the feasi-bility of using ERTS type systems for ambient monitoring,the detection of effluents and outfalls and the mapping ofdispersion currents.

EPAs regional officers have expressed an interest inover 40 of the scheduled ERTS experiments. This regionalinterest extends to plans for actually monitoring 15 of theproposed experiments.

EPA's Office of Monitoring is also experimenting withthe use of data collection platforms, in estuarian, coastaland river environments.- more -


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REMOTE SENSING

What is remote sensing? Very simply, it is the measuringof an object from a distance. For example, a camera is aremote sensor in that it measures reflected light withouttouching the object being photographed. Other examples ofremote sensors are human eyes, microwave radiometers,photomultiplier tubes, solid state detectors and spectrometers.

Remote sensing is a rapidly advancing technology. Unlikesome technologies, remote sensing does not pollute. On thecontrary, the use of remote sensing may help to preservequality of the environment by detecting pollution early andimprove the standard of living for Earth's increasing popu-lation by better utilization of our agricultural resources.It has the potential for revolutionizing the detection andcharacterization of Earth's natural resource phenomena.

Humans collect information through the five senses ofsight, sound, taste, touch and smell. Most of the informationthat the Earth reflects or radiates can't be seen by the humaneye. For example, in the near infrared, which is just slightlylonger in wavelength than red, healthy vegetation is evenbrighter than the green radiance which our eyes can see.This near infrared information can be particularly valuableto farmers and agriculturists because it can reveal whethercrops are healthy or sick.

Since objects have different physical and chemicalproperties, they tend to radiate different amounts of energyin the form of electromagnetic waves. Thus, a scene is madeup of many small radiating elements, and every object couldconceivably radiate different kinds and amounts of reflectedand emitted energy.

The wavelengths of the electromagnetic spectrum used inremote sensing range from about 0.1 micrometers (x-rays) to10,000 micrometers (radio waves). Only a small portion ofthe total spectrum can be seen with the human eye. Thevisible portion of the spectrum is from 0.4 to 0.7 micro"meters. These wavelengths, or frequencies, quantify thecolors of the rainbow violet, indigo, blue, green, yellow,orange and red.No single instrument is capable of sensing and measuringenergy at all wavelengths of the electromagnetic spectrum.Therefore, several devices are necessary if all the energy

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A sensor which measures the amount of energy being radiatedas a function of frequency or wavelength is called a multi-spectral sensor. It measures the spectral characteristics ofenergy radiating from a scene or object.The Department of Agriculture has been using remotesensing in the form of black and white aerial photographysince the 1930s to measure crop and land use acreages fortimber inventory and management, recreation and urban plan-ning, as a base for soil maps and as a tool for crop esti-mates and yield predictions.NASA and the Department of Agriculture have been workingclosely since the mid-1960s on high altitude tests of thenecessary multispectral sensors and techniques necessaryfor an efficient inventory of Earth's natural resources.The choice of sensors for ERTS-A was influenced heavily bythis work.Since early in the history of aviation, remote sensingdevices in the form of aerial photography have played anincreasingly significant role in military and geographicalinvestigations. With the possible exception of the seismo-graph, aerial photography has become the most successfulmineral exploration tool in the history of mankind.In Canada airborne electromagnetic, magnetic and gravitymethods have been combined with aerial photography to achieveperhaps the greatest airborne usage of remote sensing formineral exploration objectives. Hundreds of thousands ofmiles of surveys have been carried out, resulting in suchfinds as the Manitoba nickel deposits of InternationalNickel and the base metal discovery of Texas Gulf Sulphurin the Timmins, Ontario, region.In 1964, the U.S. Geological Survey, long a lead agencyin airborne surveys, entered into a cooperative agreementwith NASA to investigate the feasibility and applicationsof remote sensing from space, relative to geologic studies.

Remote sensing won its "photographic wings" with theadvent of the airplane and advanced rapidly during WorldWar II because of military reconnaisance requirements.Multispectral scanning came into existence in the 1960s,and remote sensing advanced with space age technology.

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E R T SSPACECRAFTSOLARPADDLES

DATA COLLECTIONSYSTEM ANTENNA( D C S )

MULTI-SPECTRAL SCANNER( M S S )

RETURN BEAMVIDICON CAMERAS(3)( R V B )


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THE ERTS-A SPACECRAFT

The ERTS-A spacecraft design is based on the flight-proven Nimbus series of experimental meteorological satel-lites, first launched in 1964. Four Nimbus satellites builtfor NASA by General Electric, have been orbited in the pasteight years and all have logged technological and meteorolo-gical firsts.

ERTS and Nimbus share the same basic design for thestructure and thermal subsystem, power subsystem, attitude andcontrol subsystem, telemetry, and tracking and command subsystem.

Unique ERTS requirements include an orbit adjust sub-system, a dual telemetry tracking and command subsystem anda wideband telemetry subsystem for sensor data transmission.Structure and Thermal Subsystem

The spacecraft configuration packages payload equipmentcentrally in a ring structure at the base of the spacecraft,providing proximity between the payload sensors, theirelectronics, and wideband communications equipment.

The three Return Beam Vidicon (RBV) camera heads aremounted to a common baseplate, structurally isolated from thespacecraft, to maintain accurate alignment.

A superinsulation blanket surrounds equipment on thering structure except for specified radiator areas whereheat is rejected from the camera section. During minimumoperating periods heaters are used to maintain temperaturelevels.An active louver system around the ring maintains theoverall structure and bay electronics very close to thenominal 20 degrees Celsius (68 degrees Fahrenheit).

Power SubsystemElectrical power is generated by two independently

driven solar arrays developed by RCA, with storage for eclipseperiods and launch provided by eight individually controlledbattery modules with a capacity of 36 ampere hours. Totalcapacity of the regulated power bus is nearly 1,000 watts.- more -


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The solar arrays are canted to a fixed angle when theyare deployed in orbit to obtain maximum solar conversionefficiency for the mid-morning equator crossing for ERTS-A.

Attitude and Control SubsystemPrecise attitude control with an Earth pointing accuracyof less than 0.7 degree in all three axes (pitch, yaw androll) is accomplished by a three-axis attitude control sub-system using horizon scanners for pitch and roll control anda gyrocompass for yaw orientation.An independent passive attitude measurement sensor

operating over a narrow range of about two degrees providespitch and roll attitude data accurate to within 0.07 degreeto aid in image location.

Orbit adjustment capability is furnished by a monopro-pellant hydrazine subsystem employing one-pound force thrusters,This system removes launch vehicle injection errors and pro-vides periodic trim to maintain a precise orbit.

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THE SENSORS

ERTS-A will carry two multispectral sensors, themultispectral scanner subsystem (MSS) and the return beamVidicon (RBV) subsystem, and a data collection system (DCS).The two sensors will repetitively take photo-like imagesof the Earth while the DCS will collect environmental data ofvarious types from ground-based remote platforms. A highperformance tape recorder, the wide band video tape recorder(WBVTR) will store photo images from the RBV and MSS asneeded when the satellite is out of range of a direct readoutdata acquisition station.The development of the MSS and RBV to meet the demandingperformance requirements of the ERTS-A mission with its'stringent spacecraft weight and power constraints is considereda major technological achievement by NASA engineers.The MSS and RBV will obtain images in two visible wave-length bands, 0.475-0.575 micrometers and 5.80 to 6.80 micro-meters for the RBV, and 0.5-0.6 micrometers and 0.6-0.7 micro-meters for the MSS. The third band in the RBV is 0.690-0.830micrometers and in the MSS 0.7-0.8 micrometers. Both of these

bands are in the near infrared. The MSS has a fourth band ata longer wavelength also in the near infrared, 0.8-1.1 micro-meters, which will provide data of great interest to hydro-logists and agriculturists.

First Band (0.5-0.6 micrometers)Light of this spectral range appears green to the eye.Water is more or less transparent in this band which enhancesfeatures within the water, like sedimentation. The oceanbottom, such as shallow areas of the Bahamas, might beseen in this band.

This band has some limitation because scattering oflight in the atmosphere makes "seeing" conditions difficult.

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Second Band (0.6-0.7 micrometers)This band appears red. Unlike the first band, thisband is excellent for seeing through the atmosphere from

space. It is especially good for land use mapping whereregional population patterns need to be observed againstvegetation patterns. A large group of principal investi-gators, about 20-25, are interested in such investigations.

The red band shows a good contrast between natural sur-face cover, like vegetation and soil, against man-madestructures. Many man-made structures appear very brightwhile vegetation shows up very dark. Soil which has becomeexposed due to a man-made activity (a new housing developmentfor example) can be seen in this band.Study of desert related phenomena is excellent inthis band because of the high contrast between vegetation

and soil.

Third and Fourth Bands (0.7-0.8 and 0.8-1.1 micrometers)These two bands are in the near infrared (invisibleto the human eye) portion of the spectrum. The fourthband, 0.8-1.1 micrometers, involves only the multispectralscanner. Water will be black in both of these bandsbecause water almost totally absorbs the radiant energy in

these frequencies.Things look different to instruments in the infrared

as compared to the visible. The most significant character-istic about infrared bands is that vegetation appearsbright, and water appears dark. As a comparison, vegetationis as bright in the infrared as snow is in the visible.Wheat in the first band (green) reflects about 20 per centof light from the Sun. In the second band (red) approximately95 per cent of the energy is absorbed by the plant and inused in the photosynthesis of carbohydrates in chlorophyll.This band is in fact called the chlorophyll absorption band.In the third, and particularly the fourth band, wheatreflects about 80 per cent of the radiation. It standsout in the infrared somewhat like snow does in the visible.

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R E T U R N B E A MV I D I C O N ( R B V )

18. 5 KM

PATHG S F CM I S S I O N A N D D A T A O P E R A T I O N SM A Y 1972500-72-74


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- 36 -Vegetation brightness depends on several things. Forone, it depends partly on the type of vegetation bigleaves will be brighter than small leaves. So, hard woodtrees will show up brighter than pine trees. Tobacco,because of the texture of its leaves, will be brighterthan wheat. Secondly, crop brightness depends on plant

health. Healthy crops, in the infrared, will be much brighteithan diseased vegetation.Band three on the MSS (0.7-0.8 micrometers) was selectedbecause it is in this band that the earliest detection ofdisease will be possible.On any single photograph it would be difficult orimpossible to detect a diseased condition in a mixed foreststand. ERTS however will provide repetitive coveragepermitting the pathologist to compare sequential picturesand observe that abnormal changes have occurred.

Return Beam Vidicon SubsystemThe 5.08-centimeter (2-inch) RBV three-camera subsystem,built for NASA by RCA Astro Electronics Division, Princeton,N.J., will survey the Earth via three co-aligned camerasensors, each viewing the identical scene but in a differentspectral band.When the separate images from the three cameras (similarto TV picture tubes) are processed and superimposed in their

respective colors, they provide a single full-color imagecontaining the radiometric and cartographic informationrequired for the ERTS system. The RBV has a much highersensitivity than the normal vidicon camera.The three spectral regions covered by the three-camerasubsystem are the blue-green (0.475-0.575 micrometer); red(0.580-0.680 micrometer); and near infrared (0.690-0.830

micrometers).The three cameras are exposed simultaneously to facili-tate registration of the three separate images into thefinal color composites.The cameras do not carry film. When their shuttersare operated, images are stored on photosensitive surfaceswithin each vidicon camera tube and then scanned by aninternal electron beam to produce a video picture. Itrequires about 11 seconds to read out all three tubes andtransmit the pictures directly to Earth. If desired, thepictures can be stored on the wideband video tape recorder.

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The cameras will be shuttered every 25 seconds toproduce overlapping pictures of the ground scene below thespacecraft.Each photo processed by the camera subsystem coversan Earth area 185 kilometers (115 miles) by 185 kilometers(115 miles). These individual photographs can be collatedto provide a continuous swath along the spacecraft orbitsubtrack.The overall three-camera subsystem is comprised of thefollowing electronic units:Three camera sensors;Three camera electronics units; andA common camera controller and combiner.A base plate serves as a precise alignment referenceplane and thermal control element. Each of the three camerasensors includes a return-beam vidicon, electron optics,electromagnetic deflection circuitry, electromechanicalshutter, lens and thermoelectric cooler.The vidicon imaging tube is a magnetically deflected,magnetically focused device with a 5.08-centimeter (2-inch)diameter face plate. Optical filters in the lens assembly

of each camera sensor determine the different spectral rangeallocations for each.The lens assembly provides a 15.9-degree field of viewacross the diagonal portion of the 2.54-centimeter (1-inch)square usable format of the vidicon face plate. A depositedreseau pattern on the face plate establishes a geometricreference for the later registration of the three separate

images to make a color picture. The shutter provides forexposure of the vidicon, and it can be programmed for one offive exposure times to accommodate variations in scene illumi-nation. The thermoelectric cooler controls the thermalenvironment of the vidicon face plate.Each camera goes through four operational modes erasemode, prepare mode, expose mode and read mode in takinga picture of a scene. The duration of a picture-takingsequence is 25 seconds, with the erase, prepare, and exposemodes being simultaneous for the three cameras and the readmode being sequential.

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MULTISPECTRALS C A N N E R

(MSS)

GSFCMIS S I ON AN D D A T A O P E R A T I O N SM A Y 1972500-72-73


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Multispectral Scanner SubsystemThe MSS, built by Hughes Aircraft Co., is an optical-mechanical sensing system which will simultaneously detectoptical energy in four spectral bands, including the nearinfrared. It weighs about 54 kilograms (118 pounds).The four bands are the visible green and red bands(0.5-0.6 and 0.6-0.7 micrometers) and two near infraredbands (0.7-0.8 and 0.8-1.1 micrometers).The MSS will scan a swath of Earth 185 kilometers(115 statute miles) wide during each orbital pass. The width

of the stip of Earth scanned by the MSS will be identicalto the swath of the RBV camera subsystem.The scanning will be achieved by means of a mechanicallyoscillating flat mirror which will flip-flop from side-to-sideabout 13 times a second during the orbital trace around Earth.The images made from the MSS data will be of excellentquality and will be photograph-like in appearance.Sensing in a variety of wavelengths to be obtained bythe MSS increases the possibility of identification of

important features in a particular area. The greaternumber of spectral bands used will make the identifying ofresources more complete and reliable.The purpose of the scan mirror assembly in the MSS

is to reflect light from the Earth's surface into the opticalsystem of the scanner. In operation this is how the MSSwill work:The Earth will be scanned by the moving mirror, whichis elliptical in shape with a minor axis of approximately 23cm (9 in.) and a major axis of 33 cm (13 in.). It is orientedat 45 degrees with respect to the scene and the double

reflector telescope type of optics. As the mirror oscillatesnearly 3 degrees about its nominal 45-degree position itwill scan an 11.5 degree field of view.- more -


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- 41 -During the actual scan period the mirror coasts inertiallywith only a soft spring force acting upon it. This is composed

of a flexually suspended rotating segment which permitsthe mirror to strike bumpers or stops that reverse the rota-tion of the mirror during each cycle. An electromagnetictorquing device restores the energy lost during mirrorimpacts against the bumpers during each cycle.During the orbital sweep, the scan mirror mechanism scansa 185-km (115-statute-mile) swath from side-to-side as thesatellite progresses southward above the Earth path beingscanned. The mechanism has a nearly symmetrical scan pattern,the oscillations in both directions requiring the same amountof time. Contact of the impacting springs against the mirror

occupies only a brief time (4 milliseconds) during eachoscillation.Six scan lines are imaged in each of the four spectralbands during each orbital sweep. The scan lines are defined

by fiber optics which transmit energy from the imaged spotthrough a spectral filter to a detector for that specificspectral band.During the scan retrace, a rotating shutter blanksout the scene and sweeps the image of a calibration lampacross the fiber ends to measure radiometric levels. Onceeach orbit, sunlight is flashed across the fiber ends tocheck the accuracy of the calibration lamp.To transfer the video signals to the ground receivingstations a multiplexer electronics unit encodes the 24 scandata signals into a single signal suitable either for realtimetransmission or storage aboard one of the tape recorders for

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- 42 -DATA COLLECTION SYSTEM

The ERTS-A data collection system (DCS) will provideusers of the space data with near real time environmentalinformation collected from ground based sensor instruments.The ground base instruments are connected to electronic unitscalled platforms.

The platforms are remote data gathering units which acceptsensor data such as measurements of soil, water, air and otherparameters, convert the data to a convenient form and transmitthe data by telemetry to the ERTS-A. The satellite immediatelyrelays the platform data to the receiving site, which in turnrelays it to the ground station at Goddard.

The ERTS-A DCS provides data retrieval from platformssituated within the continental United States and has capabilityfor coverage of platforms situated in the near Pacific, off-shore Atlantic and parts of Canada and Mexico. The platformand receiving station must be in view of the satellite.

Some examples of how the DCS platforms can be used are:Water Resources Detect water pollution trends, providean inventory of lake and reservoir

levels, show rainfall and snow levelsand allow quicker prediction ofpotential floods.Agriculture Monitor crop conditions and by means

of precipitation and soil moisturemeasurements, contribute to droughtpredictions.Forestry Measure precipitation, soil moisture,temperature and wind to aid in firehazard prediction.Wildlife and Fisheries Management Can provide forbiological and ambient environmentalmeasurements.Meteorology -- Aid forecasting by making availableinformation on air and water tempera-tures, barometric pressure, and snow,ice and glacier conditions.

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ERTS-A carries two identical wide band video taperecorders (WBVTR), built by RCA Government Commercial SystemsDivision, Camden, NJ, The WBVTR is the largest tape recorderever flown in space (35 kilograms - 76 pounds), and it hasthe highest storage capacity of any recorder ever orbited.The WBVTR has a digital bit rate of 15 million bits per secondand a storage capability of 3 x lO^ (3 followed by 10 zeroes)bits. The normal tape recorder used in space employs a tapeto head speed of 76 centimeters (30 inches) per second whilethe WBVTR used a tape to head speed of 5,080 cm (2,000 in.)per second.

The WBVTR subsystem consists of two recorders either ofwhich can record and reproduce image data from either theRBV or the MSS. Two recorders allow simultaneous operation.The WBVTR has a designed lifetime of from 500 to 1,000 hoursof operation which is sufficient to support a one-year space-craft lifetime.

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GROUND DATA HANDLING SYSTEM

The ground data handling system (GDHS) is at the NASA/Goddard Space Flight Center, Greenbelt, Md. The GDHSincludes an operations control center (OCC) for operatingthe spacecraft, and the NASA Data Processing Facility (NDPF)for processing and distributing film images from the ERTSsensors to users around the world.

The General Electric Company is prime contractor for theGDHS. The Bendix Corporation and the Wolf Research and Develop-ment Corporation are major subcontractors for the NDPF sub-systems.Systematic repeating Earth coverage under nearly constant

observation conditions will provide for maximum usefulness ofthe multispectral images collected.Operations Control Center

The OCC is the hub of ERTS daily command and controlactivities. Operating 24 hours a day, the OCC will command thespacecraft as well as the observatory sensors. The OCC willbe in touch with ERTS-A through the Alaska, California orGoddard data acquisition facilities on 12 or 13 of the 14daily orbits.

The OCC computers will process spacecraft and sensor"housekeeping" data, command generation, displays, systemscheduling as well as pre-processing of Data Collection Systemexperiment information.Operations in the OCC will interact with the computer andits software by means of operations consoles; each console

will have a cathode ray tube display and other status and alarmindicators. The consoles will provide the operations personnelwith all the information required to assess the health of thespacecraft and payloads, and to make and rapidly implementcommand and control decisions.The NASA Data Processing Facility (NDPF)

The NDPF has been designed to produce controlled qualitydata and photographic images telemetered from ERTS and todistribute them to user agencies and principal investigators.

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The NDPF has the capability of handling 10,000 images aweek. Film products available are black and white positiveand negative transparencies, black and white and color printsand color transparencies. Magnetic taped image data will alsobe duplicated and distributed.The NDPF is composed of an image processing area anda data services laboratory. Each week in the image dataprocessing (IDP) area, over 9,000 taped images will be con-

verted to film in the Initial Image Generating Subsystem (IIGS)and about five percent of these are precision processed togenerate orthophotos.About 10,000 color composites are made and about 750 imagesare generated on computer readable tape during the same period.

The Data Services Laboratory (DSL) has the capacity to servicethe ERTS users weekly. The DSL also provides library servicesand a browse file for the users as well as production control to efficiently operate the NDPF in response to requests fordata.

The NDPF is capable of handling 188 RBV or equivalentMSS operations per day. This loading yields 1,316 scenesper week each of which produce seven spectral images to givea total of 9,212 spectral images 185 x 185 km (115 x 115 miles)per week.

These data, received on video tape are converted to highquality film images on 70 mm film by an electron beam recorder.This conversion requires about 80 hours per week, includingmaintenance.

In this conversion, radiometric corrections are made tothe MSS data and the MSS data is framed to correspond to RBVimages. Both the RBV and MSS data are geometrically correctedusing error data acquired from satellite attitude telemetryand from the Scene Correcting Subsystem.

Copies of all ERTS images will be forwarded to the Depart-ment of Interior's Earth Resources Observation Systems datacenter in Sioux Falls, SD, the National Oceanic and AtmosphericAdministration, Sutiland, Md, the U.S. Department of Agriculture,Washington, D.C. and the selected ERTS investigators. Publicaccess to the ERTS-A data will be primarily through theDepartment of Interior's EROS facility at Sioux Falls. Costof the data will be, essentially the expense of reproductionand handling. Ocean and coastal data will be available fromthe NOAA.

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NDPF SUBSYSTEMS

Initial Image Generating Subsystem (IIGS)The IIGS produces corrected 70mm images of video datafrom either the RBV video tapes, MSS video tape, or fromspecial processed sensor data.It also produces a tape record of either the RBV (con-verted to digital) or MSS data in a format acceptable fordigital subsystems. Only one percent of the RBV and fivepercent of the MSS data is digitized. This element recordsannotation data regarding image location and time and agrey-scale for calibration of subsequent processing steps onits output images. The IIGS also applies initial radiometricand geometric corrections to the image video. The corrections

performed here on all bulk data will allow registrationso that good color composites may be generated from bulk data.The 70mm images produced by IIGS are developed in theNDPF photographic processing subsystem and inspected forquality and cloud cover. At this stage the images defined byusers as being useful in the NDPF information system will beenlarged, printed and distributed to ERTS users; the necessary70mm images will be submitted to the Scene Correcting Subsystemand enlarged black and white or color composites will beproduced, printed and distributed to ERTS users.In addition to the ERTS data that will be made availableto investigators by NASA, the Department of Agriculture, theDepartment of Interior and the Department of Commerce willmake ERTS data available to the respective user communitieson a reimburseable basis. The Agricultural Stabilization andConservation Services (ASCS), Western Aerial PhotographyLaboratory at Salt Lake City, Utah will receive positive andnegative film from the NDPF and make photographic reproductionsfor USDA agencies and its normal user community on a reim-burseable basis.

Scene Correcting Subsystem (SCSS)The SCSS accepts the 70mm images produced by IIGS andthrough a hybrid processing system produces corrected filmimages on a 24-centimeter (9 1/2-inch) format.

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This element removes geometric distortions and performsprecision location, 91 to 244 meters (.300 to 800 feet) andscaling of the corrected video relative to map coordinates.

Automated research and ground control point processingis used to perform these corrections.Digital Subsystems (PS)

The Digital Subsystem reads the high density digitaltapes prepared from IIGS and SCSS and edits and formats thisdata on computer-readable digital tapes for distribution toERTS users. An output tape is produced which when processedby the SCSS, will produce an annotated image showing thelocation of the encoded region; a selected section of animage will be produced on 24 cm (9 1/2-inch) format film.User Services

All data entering the NDPF will be categorized, loggedand stored. Users will have access to this information throughseveral files maintained by User Services.Subscribers to the User Services will be supplied with16mm microfilm files, data abstract catalogs, and coveragecatalogs on regularly scheduled service.The RBV images are nominally 185 x 185 km (115 x 115statute miles) in size and will be at 1:1,000,000 scale whenpresented in a usable 18.5 cm (7.3-inch) square format on astandard 24-cm (9 1/2-inch) paper format. The MSS dataconsists of successive scan lines cross-track and is put into

a frame format by the NDPF.When the RBV and MSS sensors are operated simultaneously,the frames will be made so the data cover the same area.The annotation will list sensor, time of exposure, orbitnumber, subsatellite point, picture center location, Sunazimuth and elevation angles, spacecraft heading, spacecraft

attitude and ground receiving site identification.The spectral band identifiers in the annotation block

are arranged so they show through without obscuring each otherwhen a color composite is made. Therefore, the spectral bandsused to make each color composite can be readily identified.

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NASA G-72-8203


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SCIENTIFIC DISCIPLINE AREAS OF ERTS-A INVESTIGATIONS

The general research areas to be addressed by ERTS-Aare:Discipline Number of Investigations

Agriculture/Forestry 49Environmental Quality/Ecology 60Geography/Demography/Cartography 27Geology 74Hydrology 36Interpretation Techniques Development 22Meteorology 5Oceanography 30Sensor Technology 2Total 305

The actual number of investigations finally approvedmay vary somewhat from the number listed above. As of July 5,1972, contracts or agreements have been executed for investi-gations .

AGRICULTUREAgriculture economists estimate that every $1.00 spent

on remote sensing research promises to return $5.00 in benefits.These global benefits over the next two decades are forecastedto total $45 billion if the proper investments in controltechniques are made.

The Department of Agriculture has been using remote sensingsince the 1930s, in the form of black and white aerial photo-graphy to measure crop and land use acreages, for timberinventory and management, recreation and urban planning, soilmapping, etc. - Is also used in connection with other infor-mation to make crop yield estimates and other predictionsvital to the management of the nation's agricultural programs.

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Farm census is now taken every five years. Scientistsanticipate that an Earth resources satellite may ultimatelymake it possible to take the census annually with a corre-sponding improvement in the accuracy of agricultural sta-tistics and management.Some of the types of crops which scientists will attemptto identify from ERTS-A data includes wheat, sugar beets,alfalfa, corn and grain sorgum, mixed grain, fields beans,potatoes, cotton, soy beans and spring wheat.One of the proposals for ERTS-A is #049. The scientistin charge of this proposal is Dr. David A. Landgrebe from

Purdue University. Dr. Landgrebe's proposal involves thestudy of the Wabash River Basin, an important agriculturalarea common to Ohio, Indiana and Illinois. It covers abouttwo thirds of the State of Indiana, less than one third of theState of Illinois and a small part of Ohio."The largest land area in the Wabash River Basin is inagriculture," Dr. Landgrebe said. "This general area is partof the great corn belt. But we also grow a lot of soy beans

and even some wheat and oats. Much of the area is still inthe natural state. And we have a sizeable urban area. Sowe have a good mixture of land to study. ERTS photos will bea big help in providing us with the first good map of thevegetation of the Wabash River Basin."

While a lot of our time in this area has been devoted toagriculture, we've also spent a lot of time looking into thefields of geology, geography, hydrology, and general land use."We have an interesting activity going with the MarionCounty Division of Zoning and Planning (Marion County includesIndianapolis). We hope to work with the city and countryurban planners in using ERTS imagery to help them determine

the ways ERTS data can be useful in their planning activities."With most urban areas you always have the problem oftrying to determine the best use of landresidential, in-

dustrial or agricultural. And even if you do have a wellthought out plan for the best use of land, it's always aproblem of keeping track of what's happening. With ERTSimagery we expect to show that the job can be done routinelyand relatively inexpensively when you consider that the coveragewill be every 18 days," said Dr. Landgrebe.


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"Possibly the biggest achievement of ERTS-A will beits ability to repeatedly map large areas, more quicklyand economically than in the past," Dr. Landgrebe concluded.Remote identification of most crops can now be accomplished

with multispectral aerial photographs. It also is possibleto determine whether a crop is healthy or under severe stress.Most experts predict that it may soon be possible todetect the stages of some plant diseases so that remedialaction can be taken in time to save a crop. And, they expect

someday to be able to use sequential images of a field inits various growth periods as a tool to assist in predictingyields.During the 1971 growing season in the United States,

several grovernmental agencies and selected corn belt statesconducted a cooperative study of southern corn leaf blight.In 1970, about 15 percent of the U.S. corn crop, weredestroyed because of this fungus disease, combined in someareas with severe drought.

Together with ground studies, high-altitude aircraftrepetitively photographed about 116,000 square kilometers(44,787 square miles)of the corn belt, using special infraredand color film. Results of that study show that a diseasesuch as corn blight can be successfully monitored throughremote sensing.

FORESTRYThe Forest Service was directed by Congress in 1928to maintain an inventory of the nation's forest resourceson both private and public lands. Because of sheer size,more than about 2 million square kilometers (500 millionacres) it has been difficult to keep an up-to-date inventory,

and to stay abreast of the rapid changes in America's forests.The northern temperature zone produces about 85 percent

of the industrial wood consumed in the world. Yet it isthe tropical forests (the Amazon Basin) which contain thelargest share of the world's reserve of wood. The extentand productitivy of species or species groupings in tropicalforests is largely unknown because man has never seen muchof that area. ERTS-A will provide man with his first globalreconnaissance inventory of timber.

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"Not related to forestry, but an area where ERTS-A willplay a great role is hydrology," said Dr. Colwell, Professorof Forestry at the University of California. "The snow linewhere the line builds up in the winter and where it is whenit starts to melt in the springwill be of tremendous valuein preparing reservoirs to handle the spring run-off withouthaving a big flood."Another importance of ERTS-A will be the mapping oflarge areas that are being cleared of wildland to be put intosuburban developments or agriculture," Dr. Colwell added."ERTS imagery will show an area change on a seasonal basis.This will permit us to determine whether a pioneer who triedto establish agricultures in a previously uncultivated areamade a go of it or had to fold his tent and leave."There is another area of importance to ERTS-A and

that is cloud cover. While many people say that one of thedisadvantages of space imagery is the fact you can*t seecertain areas of the Earth because of clouds, I think thatclouds can be advantageous to a somewhat cooperating extent."By observing the amount of cloud cover over a given area,man can determine the annual amount of sunlight that is hittingthe terrain below. This in turn will help him determine thebest type of crop to be grown in any one given area,"Dr. Colwell concluded.Scientists working on the earth 'resources program predictthat, ultimately, satellite imagery will provide informationnecessary for better forest management. For example, it willidentify those forest areas being attacked by insects anddisease in time to save them and be capable of providing earlydetection of forest fires.

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- 55 -OCEANOGRAPHY

The oceans, covering 70 percent of our planet, are thebreeding grounds for many of our weather systems, are asource of food, a means of transportation, potential sourceof minerals, and an important indicator of the health of life-sustaining processes on Earth.

Oceans absorb carbon monoxide (CO) and carbon dioxide (CO-),and provide oxygen, heat energy, and water vapor for theatmosphere. Photosynthesis in the ocean's surface layer isthe key life process of the marine ecosystem. The effect ofmarine pollution on these life-sustaining processes is poorlyknown.

Because of the vastness of the seas many of thesefeatures from an economic standpoint, can be observed bestfrom satellites.

Currently, technology is struggling' with the problem ofseparating atmospheric effect from the ocean color signals.Visible sensing in the blue-green portion of the spectrumappears to have the greatest potential. While sensor tech-nology is nearly adequate, much more understanding of funda-mental phenomena will be required before ocean color sensingcan be profitable used.

The health of the oceans can be assessed through their color,Blue oceans imply an absence of chlorophyll and, thus, lowfood productivity. The greener the ocean the greater itsproductivity. Measurements of "greeness," together with watertemperaturea known factor in the feeding habits of fishcan provide valuable information for the fishing industry.Global surveys of ocean color and chlorophyll contour mapscould provide insights into the health of the ocean, itsability to absorb CO and CO~, rate or production of oxygenand release to the atmosphere and its implications to marineproductivity.

One of the ERTS-A investigations concerned with oceanographyis Proposal 172 under the direction of Dr. Karl Szekielda fromthe University of Delaware.

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- 56 -"We hope to get some idea of the distribution and thebehavior of chlorophyl in the ocean and the dynamics ofphytoplankton. We are especially interested in the rela-tionship of phytoplankton with very small organisms havinga diameter of about five microns because they are very

important for the whole life cycle in the ocean."The big advantage of ERTS is going to be its abilityto measure large areas, rapidly, which you ordinarily cannotdo from ships. The concentration of chlorophyll changesvery rapidly, in just a few days. If you take these samemeasurements from ships, it may take you a week or two tomove from one region to another. By the time you reach yournew destination, the whole picture might have changed. Youwould also need many ships. It just wouldn't be economical,"Dr.Szekielda concluded.Another oceanographic study is ERTS-A Proposal 063directed by Dr. Fabian C. Polcyn of the University ofMichigan."We are going to use ERTS photographs to locate under-water features hazardous to navigation with an accuracybetter than what is now available," Dr. Polcyn said."The second problem we plan to look into with ERTSimagery is a way to measure water depth in this same geo-graphical area. We have achieved about 10 percent accuracyof measuring water depths through aerial photography."We have been working with several techniques to measurewater depth through remote sensing. One of the techniquesinvolves the diffraction of waves over the shallow featuresby looking at the change in water wave length. The secondtechnique involves computer processing of two light wave-lengths from the ERTS multispectral scanner. The depth willbe computed based on the selective transmissions of twodifferent wavelengths."Color shading in ERTS photographs will display valuable

information," said Dr. Polcyn. "The shallow areas will appearblue/green as opposed to darker blue shades for deeper water.

"Our results should be most helpful to navigators usingthese waters and similar waters around the world. Our findingswill go to the National Oceanic and Atmospheric Administrationand to the International Hydrographic Bureau in Monaco sothat current navigation charts can be changed and updated,"Dr. Polcyn concluded.

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GEOLOGY

As a professor once said, "Unlike orchards, mines bearno second crop." The known mineral reserve of the worldis not great when compared to the rapidity with which manuses it. However, things look better considering the newdiscoveries which might be available through remote sensing,Man's known reserves of oil, gas and minerals generallyhave increased rapidly during the past 20 years, duemainly to improvements in remote sensing.

ERTS-A is expected to improve the geologist's map ofthe distribution of rocks and structures exposed at theEarth's surface, which is one of his principal tools fordiscovering new mineral deposits.It will be possible with satellite imagery to locatefaults, and other anomalies which frequently indicatevaluable mineral deposits, even when they are buried undersand."Contrary to what anyone says, we are not going todetect minerals from space," said Dr. Paul Lowman of theGoddard Space Flight Center. "It just can't be done."Dr. Lowman has been a leader in remote sensing the pastseveral years as a principal investigator of space photo-graphy from the manned Gemini and Earth-orbiting Apollospacecraft."What you will find from ERTS imagery are areas whichlook promising. Then you can go in there and furtherinvestigate these areas from the ground or through aerialphotography."A good example of this is several previously unde-tected faults which I discovered near San Diego as aresult of Apollo 9 photography of that area. As a result

of a structural feature I noted after thoroughly analyzingApollo 9 pictures, I decided to go and investigate. Soafter a five-hour plane ride and an hour and a half drivein a car I was there. After two days of field work I hadit 'nailed down.' I had discovered several new faults.Without space photographs I could have spent years lookingfor those features in these peninsular ranges near SanDiego.

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"That's what is going to happen with mineral explora-tion from ERTS. You'll be able to pick the big structuralfeatures and that is the big thing geologically. If youknow an area and you know what kind of structure is asso-ciated with ore deposits, this will enable you to pick themost promising areas for follow-up aerial photography orfor drilling," Dr. Lowman concluded.

ERTS-A experiment proposal number 103 is interestedin geology and will be run by the Argus Exploration Com-pany, a research subsidiary of Cyprus Mines Corp., LosAngeles."Our proposal will cover quite a large area," saidMark Ligett, an Argus Exploration Company scientist."The area we are interested in crosses the Great BasinProvince something like 77,970 sq. km (30,000 sq. miles).It covers a strip which goes from the eastern SierraNevada mountains in California to the Colorado Plateau innorthern Arizona and western Utah."We are interested in this area for several reasons.We have some limited Apollo imagery (color photos from theearly Earth-orbiting Apollo missions) that is oblique, whichcovers the lower portion of the southwestern United States.And we have studied some of this area with ground-based

geological maps made during the past 100 years. And, wewere immediately aware that many large regional structuresshow up in space imagery which aren't apparent in ground-based map geology," Ligett said."We are going to be interested mainly in the origins ofstructures. Some structures may be shear zones and othersmay be dike swarms."These structures form belts which are quite long andlinear. They might be too subtle to recognize on maps andtherefore we are enthusiastic about looking at them through

remote sensing," said Ligett."Image enhancement of ERTS photos will help us determineif we can identify the anomalies that we see in some spaceimagery, and then try to assess their importance to geologyand the significance they have as far as tectonics,"Ligett said. Tectonics has to do with regional geologicstructures the study of regional structural patternsand dynamics of the movement of the Earth's crust.

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"We think some of these structures may have a lot todo with Volcanic activity and earthquakes. And they mightalso play an important role in mineral exploration andhydrology," Ligett concluded.The general store of structural geologic informationis expected to be upgraded through the acquisition of muchdata that would be impossible, difficult, or economicallyimpractical to obtain by repetitive routine field mappingmethods, or by similar low altitude aerial surveys.Other possibilities, include: locations of mineralbearing fluids that form ore deposits; location of thermalanomalies in the surface which indicate the existence ofsubterrain geothermal power sources; location of rockfractures which leak lethal gases from underground fires

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HYDROLOGY

Many of the problems which face hydrologists will besomewhat helped by ERTS-A photos and the data collectionsystem which will include remote platforms in streams.

For instance, one of the problems hydrologists face isthe capacity of soil to store rainfall. They now must gointo the field, examine the soil in a few selected spots anthen make an estimate of a large area.This is the current method used to develop mathematicalmodels of water-sheds for dams and the volume of waterthey must hold. Hydrologists estimate that the estimatesare often often incorrect by 50 per cent. With large dams

costing hundreds of millions of dollars, large savings arepossible by improving these estimates. Aircraft testsindicate that ERTS-A data can lead to a considerableimprovement.In many parts of the world fresh water is a preciouscommodity and ERTS-A imagery will facilitate its discovery.Water will be especially "photogenic" in the two near infra-red bands (0.7-0.8 and 0.8-1.1 micrometers). Water willshow up very dark in this band and will contrast withvegetation which will appear very bright.One of the hydrological experiments of ERTS-A isProposal 114. Dr. Fabian C. Polcyn is the principal inves-tigator from the University of Michigan."This experiment deals with mapping of terrestial featuresin the Lake Ontario Basin. ERTS results will be coordinatedwith the International Field Year on the Great Lakes (IFYGL)program. The program will try to determine how much wateris running off and how much is naturally sinking into theland, what happens to it when it enters the lake, the amountof sediments entering the lake and the amount of beacherosion. Results from ERTS should provide a valuableinput to the IFYGL terrestial water budget program, thewater movement program and the biological chemical andfisheries program."We plan to put together a space picture of the entireLake Ontario basin from about eight ERTS-A photographs.The montage will include not only the lake but the landarea from which water drains into the lake. We are especiallyinterested in obtaining the total standing water in the basin,the general land use practices and knowledge about soilmoisture content.

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GEOGRAPHY, CARTOGRAPHY AND DEMOGRAPHY

Almost four billion humans live on less than 20 percent of the Earth's surface.Remote sensing from ERTS-A will be a big step forwardin man's ability to plan and use the land.The sensors aboard ERTS-A will make the first systematicsurveys of land use patterns over most of Earth's 151 millionsquare kilometers (58 million square miles).With all of the great technological advances, such asthe use of aerial photography, and in spite of the tremen-dous resources which are expended yearly by the combinedcartographic capabilities of all the advanced nations, theworld remains less than 50 per cent adequately mapped.Due to the vastness of our planet's surface and therapid changes wrought by man, it has been impractical tokeep abreast of even the gross surface patterns reflectingman's activities on a yearly, or much less for seasonalincrements of time.Yet, such measurements are needed to inventory culturaland natural resources and to evaluate man's potential forfurther land development.Presently, only about 40 per cent of the nation iscovered by the standard topographic map. Each quadranglemap now takes approximately four years to complete.While ERTS-A photographs will not have the resolutionof aerial photographs, they will cover very large areasand will be repetitive. ERTS photography will let mapperslook for trends and changes over short periods of time,

heretofore not possible.A land use experiment for ERTS-A is Proposal 101, land

use of northern megalopolis in the New England area. Theinvestigator is Dr. Robert B. Simpson, a geographer fromDartmo

earth resources technology satellites a (erts-a) press kit

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