The Ben Franklin: The Other NASA Expedition of Summer 1969

In the summer of 1969, NASA made history twice: once with Apollo 11, and once some 2,000 feet below the surface of the ocean. The second expedition, the drift of the submersible Ben Franklin through the Gulf Stream, has largely been forgotten, overshadowed by Apollo 11, which was under way at the same time. A short NASA film, Meanwhile, At the Bottom of the Ocean, tells its story.

The mission

The idea was not to push through the current, as a military submarine might, but to join it: to drift passively in the core of that enormous current and measure it from the inside. Along the way the crew kept continuous records of:

• drift speed, water depth, temperature and salinity;
• the marine life carried in the stream;
• the Continental Shelf, photomapped in 3D.

Over the weeks they made scientific discoveries and saw remarkable sea life, but also rode out sudden surges in the current, abrupt changes in the seafloor, and failing support systems that made life aboard increasingly uncomfortable.

Why it still matters

The film calls the Ben Franklin and Apollo 11 perhaps the greatest expeditions of their kind, closing a decade of remarkable technology. The drift produced a store of data that is still in use, helping explain the Gulf Stream's role in weather and climate.

That role shows every hurricane season. The Gulf Stream's warm water often makes hurricanes more intense as they move along the Atlantic coast — the point at which ocean currents quite literally hit home.

From a submarine to satellites

NASA now studies the ocean from orbit. Satellites measure ocean color, temperature and salinity, along with forces that shape the ocean, such as winds and sea ice.

• Ocean and air are coupled. Heat passing between the ocean and the atmosphere drives atmospheric circulation over the whole globe.
• Currents move heat. Surface currents and deep-ocean circulation spread the heat the ocean absorbs, letting the ocean act as Earth's thermostat.
• Both are parts of a larger system, a complex give-and-take that shapes the planet's climate.

From the Ben Franklin's drift to today's satellites, the film argues, NASA's study of Earth's systems has fed a better understanding of global climate change — its causes, effects and consequences.

Sources

Based on Meanwhile, At the Bottom of the Ocean, a film from NASA's Goddard Space Flight Center; a work of the United States government in the public domain.