Space Ships and Astronauts: History of Unmanned Satellites
About the history of the United States unmanned satellites, the increasing popularit in the world, uses in military, communications, navigation, and weather
Closer to home, space is getting crowded. Somebody puts up a satellite about once a week. The Dutch are doing it, the Italians, the Chinese. Most of us take for granted the Intelsat synchronous satellite communications network. These "comsats" are parked in a stationary orbit over the equator. Intelsat IV, has communications channels exceeding all the submarine cables in existence. The UN now has on its agenda a discussion aimed at prohibiting direct television broadcasting into home receivers. The technology for doing it is available, but some countries don't want their citizens to listen to another country's broadcasts.
Weather satellites, the Nimbus and new ESSA series, are doing more than helping the TV weatherman. Global hurricane and storm warnings save billions of dollars and many lives. One 24-hour series of weather pictures is worth 20,000 ship reports and is far cheaper. The typhoon which devastated Pakistan a few years ago was clearly seen and warnings issued, but land communication in Pakistan was too slow to alert the affected areas in time. Shipping companies route ships around storms at sea and cartographers are mapping the world with accuracy undreamed of 10 years ago.
The ERTS-I (Earth Resources Technology Satellite) is swamped by requests for data on crops, plant diseases and vigor, surface water distribution, air and water pollution, oil spills--the list is endless. A Gulf Coast shrimp fisherman said one picture was worth 20 years of sailing in his home waters.
Global navigation satellites allow ships to fix position in cloudy weather, thus saving lives and dollars by staying on course. They also help ships avoid storms. The ocean liner Queen Elizabeth II was one of the 1st commercial ships built to include Navsat capability. Recently an Aerosat agreement was signed for European-U.S.-Canadian air-control satellites to increase safety in the overcrowded airways.
Military satellites allow instantaneous communications and monitor troop buildup, weapons deployment, and testing. One series, the Vela Hotel, monitors the upper-atmosphere nuclear test-ban treaty. High-altitude blasts can disturb the Van Allen belt, which helps protect earth from lethal solar radiation.
Astronomical and near-earth space measurements contribute information about how solar flares disrupt communications, about the high-velocity solar wind and the shock wave formed when this wind is deflected by our magnetic shield. The Orbiting Astronomical Observatory (OAO), with its telescopes Copernicus and Uhuru, has revealed a whole chorus of radiation from the sun and stars. In late 1974, NASA received the 1st infrared astronomical data from the U.S. Air Force, exciting astronomers with the possibility of orbiting an infrared telescope. In the 1st month of operation the OAO gathered 20 times more information than earth-based instruments had compiled in the previous 15 years.
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