Skylab Earth Resources

1974 (11th) Vol.1 Technology Today for The Space Congress® Proceedings Tomorrow

Apr 1st, 8:00 AM

Verl R. Wilmarth Science and Applications Directorate, Johnson Space Center, Houston, Texas

Follow this and additional works at: https://commons.erau.edu/space-congress-proceedings

Scholarly Commons Citation Wilmarth, Verl R., "Skylab Earth Resources" (1974). The Space Congress® Proceedings. 1. https://commons.erau.edu/space-congress-proceedings/proceedings-1974-11th-v1/session-1/1

This Event is brought to you for free and open access by the Conferences at Scholarly Commons. It has been accepted for inclusion in The Space Congress® Proceedings by an authorized administrator of Scholarly Commons. For more information, please contact [email protected]. SKYLAB EARTH RESOURCES PROGRAM

Verl R. Wilmarth Science and Applications Directorate Johnson Space Center Houston, Texas

The successful launch of Skylab on May 14, 1973, Although EREP was the major facility for the provided an unique space platform for study of Skylab earth resources program, the Skylab 4 the ocean, land and atmospheric phenomena of mission of 84 days provided an opportunity to add this planet earth. At an altitude of 234 nautical a new dimension for study of the earth by using miles above the earth, the 100 ton experimental the skills of the crew to identify, describe, in station orbited the earth every 93 minutes and terpret and photo document features and process repeats the same revolution every 5 days. In a es of interest in earth surveying programs. In near circular orbit, Skylab crossed major parts conducting the Visual Observation project, 20 of the world's land masses and the Atlantic, hours of lectures were provided the crew by a Pacific and Indian oceans between 50 north and team of multidiscipline scientists and a compre 50 south latitudes. hensive data package that illustrated features and outlined observation and photographing proce During the 171 days in space, the nine crew mem dures was carried onboard the spacecraft. bers surveyed selected portions of this planet with an array of sophisticated photographic, in During the three manned missions, approximate frared and microwave sensors that have not been ly 40, 000 photographs and 220,000 feet of high previously flown for earth resources investiga density magnetic tape were acquired with EREP. tions. These sensors formed the Earth Re An additional 2000 photographs were obtained by sources Experiment Package (EREP). Figure 1 the Skylab 4 crew to document their visual ob describes the instruments and the principal use servations. The data from Skylab missions are of the sensor data in study of earth. The foot processed at the Johnson Space Center and dis print for each sensor is shown in Figure 2. The tributed to the 140 Principal Investigators (Pis) camera system consists of two parts. The mul- that represent institutions in the United States tispectral camera (S-190A) is an array of six and 19 foreign countries (Figure 3). With the 70mm cameras boresighted so the features seen exception of some of the multispectral scanner in one photograph can be simultaneously identi magnetic tapes, all of the EREP data from the fied in the photographs from the other five first and second manned missions have been dis cameras. With this system, images of earth tributed to the investigators. The data from Sky- features were obtained on color, color infrared, lab third mission are being processed, and will black-and-white infrared, and black-and-white be available to the Pis within a few weeks. Ini film. Each photograph covers 163 Km square. tial results of the investigators data analysis The Earth Terrain Camera (S-190B) overlapped will be presented at a NASA sponsored confer the field of view of the S-190A system and re ence to be held at Johnson Space Center in July corded information on black-and-white , color 1974. Although this conference will provide an and color infrared film. Each photograph covers overall view and understanding of the application 109 Km square. The infrared spectrometer was of Skylab results to earth resources, prelimi boresighted with a crew-operated movable tele nary results from EREP and the Visual Observa scope for conducting radiance measurements of tion project are summarized in this report. homogeneous areas approximately one-half kilometer in diameter. The multispectral The high spatial and spectial resolution of the scanner (S-192) is a 13-channel instrument cap camera (S-190A), S-190B) systems have pro able of measuring simultaneously in the visible, vided cartographers with prime data for use in reflected infrared and one channel in the thermal revision of topographic and photomaps, prepara infrared regions of the spectrum along a 68 Km tion of photomosaics and development of an mapping wide swath. The microwave system (S-193) cartographic technique for topographic combines a passive radiometer and an active of remote areas such as Gran Chaco, Paraguay. scatterometer and altimeter in a single frequency The data content in EREP photography is clearly of 13 OGHz . This system has an 11 Km field of shown in this Earth Terrain Camera color photo view and a two axis gimballsd antenna for use in graph of the rapidly growing urban area of obtaining data 45 forward and to either side of Phoenix, Arizona (Figure 4). this groundtrack. The sixth instrument is the L-band radiometer (S-194) that operates at a The investigator team of R. Alexander and V. 1. 4 GH frequency and has all Km field of view, Melazzo, U. S. Geological Survey, have com z pared the 1970 and 1972 land-use map of this

1-1 fields have temperatures near camera imagery of the agricultural area with the 1973 multispectral the Salton Sea which indicates that they land-use changes. They that of and identified areas of were heavily irrigated during the overflight of note that most changes involve transition from of the type of and that Skylab. These data are examples agricultural to single family residences be applied to study of value in updating information that could the EREP imagery is of great crops, to search for surface indications maps in an urban setting, stressed existing land-use of geothermal energy or mineral deposits, and to define freeze-thaw areas for crop forecasting. At the Johnson Space Center, a cooperative pro- • U. S. Department of Agriculture is gram with the Skylab microwave experiments, S-193 and to investigate the application of EREP The underway S-194, represent the first active system flown multispectral photography and scanner data to obtained over acre in space, the first measurements the identification and measurement of crop the first altimeter study area. On a tropical hurricane, and age in the Holt County* Nebraska from earth orbit. The S-193 infrared photograph taken in June measurements this 190A color combined radiometer /scatterometer/and alti 1973, in the river are circular * irrigated fields for oceano- piv meter system was designed primarily which have a quarter mile irrigation system in particular to determine approximately graphic investigations oting to the center and irrigating conditions such as wind speed, wave this photography, crop acreage sea surface 135 acres* From height and precipitation areas. On June 6, Sky- and crop vigor can be determined for use in pro the coast of 6 is lab passed near Hurricane Ava off duction, and commodity forecasting. Figure inertial mode obtained the same area; how Mexico, and in an solar a 190-B color photograph of scatterometer and radiometer times higher resolution, more a series of S-193 ever, with three Figure 11 shows location of the eye, wind information can be obtained. Note the data. detailed speeds, and the S-193 data points. Dr. Pierson different color shades in the circular fields which and of City University of New York, and Dr. R. reflect variations in stages of plant growth have completed The multispectral Moore, University of Kansas, soil and moisture conditions. analysis of these data and reported (S-192) magnetic tape data from the same preliminary scanner a reasonable correlation between the scattero area have been converted to color infrared image' 7). meter measurements and wind speed determined for comparison with the photographs (Figure 12). The radio of the scanner by aircraft underflight (Figure Although this spatial resolution used to determine areas of as observed in the photo meter data were image is not as great precipitation which degrades the scattero variations in color of the circular fields heavy graphs, meter data. indicative of crop and soil conditions are readily Because of the vast quantities of determined. An unique opportunity occurred during the last data obtained by the S-192, computer analysis and radio computer gen manned mission when scatterometer are required. Figure 8 shows the acquired on several passes over black, outlined area shown on meter data were erated map of the storm system in a decade in the three figures. In the lower left film the largest previous North Atlantic ocean. Wind speeds in excess of strip, corn is shown in yellow, grasses in red, re From 60 knots, and wave heights to 75 feet were pastures in green and all other in black. Analysis during the over corded by weather ship in the area. detailed ground study conducted completed by Dr. Pierson. is a high correlation be of these data are being flight of Skylab, there preliminary results indicate the prac computer crop identification and actual However, tween the tical use of space acquired radiometer/scattero crop variety. meter data in preparation of surface meteorolog maps of vast areas of the ocean. Dr» R. Colwell of the University of California, . ical interpretation and computer pro- . using photo The S-193 altimeter measures accurately the dis cessing, has demonstrated the utility of the and the earth's and land- tance between the spacecraft EHEP data in vegetation classification provided the first direct measure areas of California, surface and use inventory in selected ment of a sea surface depression. During the mission, several altimeter measurements were During the Skylab 4 mission, the detector assem Trench. Analy was re obtained over the Puerto Rican bly in the multispectral scanner (S-192) that for about 500 Km a sensitivity of sis of these data shows placed by a detector having of Puerto Rico, the sea surface is de in the thermal infrared region of northwest 0. 8°K NE T pressed and reaches a maximum of approximate the electromagnetic spectrum. The preliminary (Figure 13). Ac over the Salton ly 20 meters over the Trench analysis of these data acquired of comparable sea level data would in California are shown in false color quisitions Sea area require extensive ship surveys. images (Figure 9 and 10). In the visible spec white, trum, the Mojave desert appears as also obtained over areas of irrigated rectangular Altimeter data were Salton Sea as black and the coast for use in developing instru near the Salton'Sea as grays, .the Virginia agricultural plots mentation for the geodial satellite GEOS-C to be and t ans (Figure 9). These color greens, launched in 1974, variations probably represent differences in in crop growth and crop type* In the thermal of 84 days provided the tempera The third manned mission frared imagery, the apparent surface to determine man's cap with the cooler crew the opportunity tures are indicated by color to study and photograph many phenomena shown as yellow and higher temp ability temperatures on earth. In particular, their observations and eratures as shades of reds. Note that several

1-1 to and photographs have provided oceanographers systems which will enable resource managers of with information that will permit revision of more efficiently utilize the energy resources ocean color charts and the location of currents the world. and upwelling areas. Using the photographs from the first and second manned missions, Dr. Stevenson of the Office of Naval Research, iden tified turbulent eddies in the Yucatan current off the east coast of Central America. The general flow of the surface currents in this part of the Caribbean Sea arid location of the Skylab photo graphs are shown on Figure 14. In the SL-2 photograph (Figure 15) the eddies appear as smooth, relatively cloud free surfaces that are 6 to 20 Km in diameter and extend to depths greater than 100 meters. In the eddies, the sur face water temperature is several degrees colder than the normal sea water temperatures in the current. Towering cumulus clouds, which are white in Figure 15, generally form over the warm down wind current boundaries. The eddies are believed to represent upwelling of cold water and therefore are a potential source of fish. The SL-4 crew observed eddies in the Yucatan current and in several Atlantic and Pacific ocean currents. Dr. George Maul, National Oceanic and Atmospheric Administration, has described similar cyclonic eddies in the Gulf Loop Current in the Eastern Gulf of Mexico. The discovery of turbulent eddies in many ocean currents has re quired the development of new theories for modeling the atmospheric and ocean energy ex change processes.

Vast areas of the South Atlantic ocean do not have modern oceanographic charts and the location of such major ocean features as the Falkland and Brazil currents are not accurate. Because ocean currents affect weather conditions, distribution of marine life, movement of sediments and ship ping courses, the observational and photographic data acquired by the third crew over the con fluence of these currents have provided oceano graphers with new and unique scientific informa tion. Figure 16 shows the location of the currents. Within the Falkland current and in many other ocean areas, the crew observed the occurrence of major concentrations of plankton, a microscopic marine organism. Plankton is a basic ocean food and the location of the plankton are important in the search for potentially rich fishing areas. Figure 17 is a photograph of the Falkland current showing the "plankton bloom" as red. During the third manned mission, the crew's photography and observations of the dis tribution of plankton blooms in the Falkland and Brazil currents have provided for the first time information that will aid oceanographers to plot accurately the location of these currents. Similar observations and photo documentation were completed for the Humboldt current (Figure 16) and the West Wind Drift current east of New Zealand. Dr. Maul has indicated that the observations by the crew of Carr, Gibson and Pogue have added significantly to man's knowledge and understanding of the oceans.

In summary, the preliminary results of the EREP data analysis have provided information for developing future operational earth orbiting

1-3 EREP SENSORS

SENSOR NO. APPLICATION

MULTISPECTRAL S190 A THERMATIC AND LAND USE MAPPING, RESOURCE CAMERA 6 LENS INVENTORY; MEASURE OF EFFECTS OF ATMOSPHERIC SCATTERING.

EARTH TERRAIN CAMERA S190B HIGH RESOLUTION DATA FOR INTERPRETING EREP IMAGERY.

INFRARED SPECTRAMETER S19? DETERMINE EFFECTS OF ATMOSPHERIC ATTENUATION AND RADIATION FROM EARTH SURFACE.

MULTISPECTRAL SCANNER S192 MULTISPECTRAL AGRICULTURAL SURVEYS, 13 CHANNELS LAND USE DISCRIMINATION,OCEAN SURVEYS, WATER CONTAMINATION.

MICROWAVE RADIOMETER S193 IDENTIFICATION OF SEA/LAKE ICE, SNOW, SCATTEROMETER /ALTIMETER VEGETATION AND RAINFALL PATTERN RECOGNITION, SOIL MAPPING

L-BAND MICROWAVE S194 IDENTIFICATION OF LAND/WATER AREAS RADIOMETER Fig r

40 N

SI PI -60 N Ml

SI91-1/4 N Ml AT NADIR Figure 2|

1-4 EREP PRINCIPAL INVESTIGATOR PROGRAM

INVESTIGATOR DOMESTIC FOREIGN AFFILIATION INVESTIGATORS INVESTIGATORS

ACADEMIC 29

STATE

INDUSTRIAL 22

FEDERAL 40 (6 AGENCIES) 30

TOTAL 100 40 (19 COUNTRIES) Figure 3

SKYLAB PHOTOGRAPH - PHOENIX, ARIZONA - S190B

1-5 N*s*.s.73.»3. COUNTY NEBRASKA AGRICULTURAL STUDY AREA - S190B

NEBRASKA SAND HILLS ,, JDJ Figure 6.

1-6 ^•;i:f^3ii.:** !«&!:it.lM»*i^* Vf.tW*^ lf?'**K:s?\^J3S%?*:*iV, mX^J**,**^:...^.:'^, : *, « 1 e*? v ..*'* !*.,«&&••' •'.

NASA~$~73-2839 HOLT COUNTY STUDY AREA COMPUTER CLAMIIICATiON MAPS

Figure 8

1-7 S192 THERMAL BAND FALSE COLOR IMAGERY CSALTON SEA)

1-8 TRACK 49, JUNE 6,1973 STREAMLINE and ISOTACH ANALYSIS FOR AVA

Figure 11

1-9 RESPONSE OF SCATTEROMETER AT 52° OVER HURRICANE AVA

(ASPECT ANGLE AND CLOUD LOSS CORRECTIONS)

> Winds from Meteorological Analysis, with Local Fluctuations Smoothed, not from Direct Measurements.

Figure 12

SKYLAB ALTIMETER PRELIMINARY RESULTS FOR THE ATLANTIC/PUERTO RICO AREA

390 Q Of

400

X 410 O

420 u z 430

440

450

460

470

J_ 10 20 30 40 50 60 70 80 90 100 TIME IN SECONDS Figure 13

1-10 SL-2 PHOTOGRAP

105° 110° 115°

SURFACE CURRENTS IN THE CARIBBEAN SEA AND GULF OF MEXICO Figure u

TURBULENT EDDIES IN THE YUCATAN CURRENT

1-11 16

Figure

OCEAN

ATLANTIC

SOUTH

-o.

,,,

I4?i

«»««

——

«™, CURRENTS

Miimi

»--««-..

»,««»,,,

,—

~.——«

*-——

,,,^«

—

LEGEND

«-•—--———

WSH

!Ci

»,»

-«~——

FIATURiS

MAPPING

CONTAMINATION

OCEAN ATMOSPHERIC

DlSIiTi

VOLCANOIS

CULTURAL

AIR PLANKTO ANU CURRENT

Figure 17

1-13