Skylab Earth Resources

The successful launch of Skylab on May 14, 1973, provided an unique space platform for study of the ocean, land and atmospheric phenomena of this planet earth. At an altitude of 234 nautical miles above the earth, the 100 ton experimental station orbited the earth every 93 minutes and repeats the same revolution every 5 days. In a near circular orbit, Skylab crossed major parts of the world\u27s land masses and the Atlantic, Pacific and Indian oceans between 50 north and 50 south latitudes. During the 171 days in space, the nine crew members surveyed selected portions of this planet with an array of sophisticated photographic, infrared and microwave sensors that have not been previously flown for earth resources investigations. These sensors formed the Earth Resources Experiment Package (EREP). Figure 1 describes the instruments and the principal use of the sensor data in study of earth. The footprint for each sensor is shown in Figure 2. The camera system consists of two parts. The multispectral camera (S-190A) is an array of six 70mm cameras boresighted so the features seen in one photograph can be simultaneously identified in the photographs from the other five cameras. With this system, images of earth features were obtained on color, color infrared, black-and-white infrared, and black-and-white film. Each photograph covers 163 Km square. The Earth Terrain Camera (S-190B) overlapped the field of view of the S-190A system and recorded information on black-and-white , color and color infrared film. Each photograph covers 109 Km square. The infrared spectrometer was boresighted with a crew-operated movable telescope for conducting radiance measurements of homogeneous areas approximately one-half kilometer in diameter. The multispectral scanner (S-192) is a 13-channel instrument capable of measuring simultaneously in the visible, reflected infrared and one channel in the thermal infrared regions of the spectrum along a 68 Km wide swath. The microwave system (S-193) combines a passive radiometer and an active scatterometer and altimeter in a single frequency of 13 OGHz . This system has an 11 Km field of view and a two axis gimballsd antenna for use in obtaining data 45 forward and to either side of this groundtrack. The sixth instrument is the L-band radiometer (S-194) that operates at a 1. 4 GH frequency and has all Km field of view