TIME & NAVIGATION
the untold story of getting from here to there
AIR SEA SPACE page 5
page 8
page 12
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navigating in the
AIR
Aviators needed faster, more accurate, and more reliable navigation than sailors. The introduction of air travel brought new challenges for navigators. Finding position in the air was more difficult than at sea, and becoming lost often meant death. Innovators worked to adapt nautical tools and techniques for aerial use and to make them easier to use. World War II spurred great advances in air navigation to meet the urgent needs of nations at war.
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CHALLENGES of
AIR navigation
Early aviators on long flights sometimes faced great danger because they could not figure out exactly where they were. “Fixing” position over water, in the dark, or in poor weather was difficult. The consequences of getting lost could be dire. The celestial navigation tools sailors used at sea didn’t work as well in the air. Aviators needed new equipment and techniques.
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Why was navigating in the air more difficult than navigating at sea?
Speed: Airplanes moved many times fast-
er than ships, so air navigators had to work faster to fix their position. Even minor miscalculations could result in much greater errors.
Instability:
The natural roll of the airplane and air turbulence made taking accurate sightings and readings challenging.
Weather:
Haze obscured the horizon line needed for sextant sightings. Clouds could keep navigators from sighting the Sun and stars or determining wind drift.
Cockpit Environment:
Cramped open cockpits, low temperatures, and wind speeds over 160 kilometers (100 miles) per hour made air navigation unpleasant. Heavy gloves (or frozen fingers) made sighting with a sextant, determining drift, and making calculations nearly impossible.
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navigating at
SEA
Instruments to find and keep time revolutionized the way mariners crossed the oceans. In 1700, Europe’s mariners and mapmakers knew only about half the Earth’s surface with any detail. Rival nations were exploring the seas in search of greater wealth, power, and prestige. But uncharted seas were dangerous. To make ocean travel safer and faster, people had to develop better maps, better navigation tools and techniques, and better clocks.
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navigating without a
CLOCK
Mariners achieved remarkable feats of exploration using only the simplest tools. Before accurate ship clocks were common, European navigators paid careful attention to time derived from the Sun, Moon, and stars. Aware of the risks, seafarers relied on their tools, know-how, and sometimes even luck when they ventured out on the world’s uncharted, dangerous oceans. Early mariners made efforts to chart distant shorelines and ocean features even without first-hand knowledge. Europe’s first sea charts were simple outlines of coastlines made to supplement written or oral directions. They later evolved into more accurate navigation aids based on astronomy and mathematics.
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navigating in
SPACE 12
To journey across the vast expanses of space, navigators drew on age-old methods and invented new ones. Space navigators drew upon techniques used on the sea and in the air. They also had to invent a new science of space navigation, using star sightings, precise timing, and radio communications. The great distances spacecraft had to travel called for even greater precision in timing and positioning than ever before.
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reaching for the
MOON
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The United States and the Soviet Union each tried to reach the Moon with robotic spacecraft in the early 1960s. They sent spacecraft to orbit the Moon, pass nearby, or crash land on the surface. After some initial failures, advances in navigation and propulsion technology eventually led to success. With the Pioneer probes, the United States tried to send small spacecraft to the vicinity of the Moon. The later Ranger probes succeeded in crashing onto the lunar surface. The Pioneer and Ranger programs led to successes with later robotic programs and eventually human landings on the Moon.