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History of Ocean Exploration

Ocean Exploration Timeline

When was the first manned submersible launched? When was the deepest place in the ocean discovered?

Learn about the history of ocean exploration with this timeline, which includes selected notable events and discoveries.


The United States government formally began ocean exploration when President Thomas Jefferson authorized the Survey of the Coast, NOAA’s earliest predecessor.
Coast Survey soundings in support of Gulf Stream investigations resulted in the discovery of the continental shelf break and the continental slope.
Charles Wyville Thomson discovered sea life at 14,400 feet below the surface of the ocean, overturning previously held theories that the sea was lifeless below 1,800 feet.
Challenger Expedition circumnavigated the globe in the first great oceanographic expedition. Research was conducted on salinity, density, and temperature of sea water as well as ocean currents, sediment, and metrology. Hundreds of new species were discovered and underwater mountain chains documented. Modern oceanography was based on this research.
Reginald Fessenden sailed on the U.S. Coast Guard Cutter Miami. He used a Fessenden oscillator to reflect a signal off an iceberg and simultaneously reflect an acoustic signal off the sea bottom. This test marked the beginning of the acoustic exploration of the sea.
World War I accelerated oceanic acoustic research as both the U.S. Navy and the Army Coast Artillery developed research programs to devise means to detect enemy submarines.
William Beebe was lowered to 3,028 feet in a tethered bathysphere, pioneering manned exploration of the ocean with his partner, Otis Barton.
The French research submersible FNRS-3 descends to 13,257 feet off the coast of West Africa, piloted by Georges Houot and Pierre Willm, inaugurating use of manned, untethered research submersibles.
The Coast and Geodetic Survey Ship Pioneer towed the first marine magnetometer and discovered magnetic striping on the seafloor off the West Coast of the United States. This survey provided a key element to the Theory of Plate Tectonics.
Don Walsh and Jacques Piccard in the bathyscaphe Trieste dived to what was believed to be the deepest point in the Mariana Trench, recording a depth of 35,800 feet. Exploring the same area in 1998, an unmanned Japanese research vessel measured a depth of 35,886 feet.
The Deep Submergence Vehicle Alvin was constructed by the Woods Hole Oceanographic Institute. Alvin was the first U.S.-based deep-diving submersible and has now made over 4,400 descents that have led to numerous ocean floor discoveries.
Sylvia Earle led the first team of women aquanauts during the Tektite Project and set a record for solo diving to a depth of 3,000 feet.
Hydrothermal vents were discovered, along with an ecosystem that survives without the energy of the sun, by a team led by Robert Ballard.
A major El Niño event led to the installation of a Pacific equatorial oceanographic buoy array by NOAA’s Pacific Marine Environmental Laboratory. Observations from this array have since predicted the onset of El Niño and La Niña events, a major step in understanding the coupling of the ocean and atmosphere system.
September 1, a team led by Robert Ballard discovered the Titanic, the most famous shipwreck in modern history.
Declassification of GEOSAT radar altimetry data from a U.S. Navy Earth observation satellite led to worldwide mapping of the seafloor.
The first ever Census of Marine Life culminated, cataloging the diversity, abundance, and distribution of marine species in an online database.

Source: oceanexplorer.noaa.gov and education.nationalgeographic.com