Jan 22 1975
From The Space Library
22-25 January. NASA launched Landsat-2 (Landsat- B), formerly called Earth Resources Technology Satellite (ERTS-B), from Western Test Range at 9:56 am PST on a two-stage Thor-Delta booster supplemented by nine strap-on rockets. The satellite entered a near-polar orbit with a 918.23-km apogee, 912.89-km perigee, 103.32-min period, and 99.09° inclination. Primary objective of the mission was to acquire multispectral imagery over the U.S. and foreign countries in quantity sufficient to improve remote-sensing interpretative techniques and to further demonstrate the practical application of Landsat data. Secondary objectives were to acquire sufficient multispectral coverage over the U.S. to supply data requirements for the Applications System Verification Tests for at least 1 yr, to acquire multispectral coverage for at least 2 yr over the major agricultural areas of the world to illustrate further applications of Landsat imagery for crop inventory, and to demonstrate successful operation of the Data Collection System.
A 3-day delay in the launch changed the initial orbital phasing of Landsat-2 relative to Landsat-1 (launched as Erts 1 on 23 July 1972) into a 12- to 6-day repeat cycle instead of the planned 9-day cycle. However, an orbital correction maneuver beginning 27 Jan. and ending 6 Feb. altered phasing to a 9-day repeat cycle. The payload separated from the launch vehicle 50 min 3 sec after launch, followed by solar-panel deployment and earth acquisition using the attitude control system. The command system was turned on automatically, permitting activation of the payload by ground stations. During the night of 22-23 Jan. the mechanical integrity of the wideband video tape recorder was verified, Data-Collection System (DCS) activated, and data-collection platform experiment data transmitted. By 12:00 pin EST 23 Jan. all spacecraft systems were operating and by 25 Jan. the wideband transmitter, wideband video tape recorder, multispectral scanner (MSS), and return-beam vidicon (RBV) were turned on, and operating normally.
Teaming up with Landsat-1, the 953-kg Landsat-2 would provide repetitive coverage of almost the entire earth to demonstrate the practical benefits of resources management from space for NASA in cooperation with the Dept. of Agriculture, National Oceanic and Atmospheric Administration, Dept. of the Interior, Environmental Protection Agency, U.S. Army Corps of Engineers, and various state, local, and foreign organizations. Experiments included the cooperative NASA-DOA-NOAA Large Area Crop Inventory (LACIE), which combined crop-acreage measurements derived from Landsat data with meteorological information from ground stations and NOAA satellites to assess crop yields and make production forecasts. During the first yr of operation, LACIE would concentrate on U.S.-grown wheat, but the experiment would later be expanded to other crops and other regions.
Other experiments included land-use survey and mapping; mineral resources, geological, structural, and land-form surveys; water resources studies; marine and ocean surveys; meteorological and environmental studies; and interpretative techniques development.
Data were being transmitted to three NASA tracking and data acquisition facilities at Fairbanks, Al.; Goldstone, Calif.; and Greenbelt, Md. In addition, Canada and Brazil operated Landsat ground data-acquisition stations and Italy and Iran were constructing similar facilities. Data received from the satellite were sent to the NASA Data Processing Facility at Goddard Space Flight Center where 1300 images, covering 45 million sq km, could be processed each week. The data would then be forwarded to the Federal Data Center and made available to the public.
The Landsat mission was part of a U.S. program to develop remote sensing methods for improved management of earth's resources. In addition to Landsat-1 and 2, the program included remote-sensor instrument development; data-analysis research using data from spacecraft, aircraft, and ground-truth sites; low-, intermediate-, and high-altitude aircraft flights; and Earth Resources Experiment Package (EREP) experiments completed during the 1973 manned Skylab missions. (NASA MORs, 9, 23 Jan 75; NASA Releases 74-329, 75-31)
22 January. NASA's Oso 5 Orbiting Solar Observatory began its 7th yr in earth orbit. Launched 22 Jan. 1969 to study the sun and its influence on earth's atmosphere, Oso 5 had completed more than 34 000 orbits. It was the fifth of eight spacecraft launched in the OSO program to observe the sun during most of its 11-yr solar cycle. Oso 5 had been shut down 3 yr after launch but was reactivated in July 1974 after decay of the orbit of Oso 7 (launched 29 Sept. 1971). Oso 5, which had a planned lifetime of 6 mo, was obtaining data on the frequency and extent of eruptions on the sun's surface. (NASA Release 75-46)
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