Project Mohole – The deep ocean drilling project in Guadalupe Island

The project was an attempt in the early 1960s to drill through the Earth’s crust to obtain samples of the Mohorovičić discontinuity, or Moho, the boundary between the Earth’s crust and mantle.

Mohole was to provide an Earth Science complement to the high-profile Space Race. While such a project was not feasible on land, drilling in the open ocean would be more feasible, because the mantle is much closer to the sea floor.

One of the six submerged buoys used for dynamic positioning in Project Mohole. They were lowered to about 60 m into a circular pattern. The CUSS I would then use sonar to manoeuvre itself in the center of that circle. / Image: National Science Foundation (NSF), nsf.gov

The project was initially led by a group of scientists called the American Miscellaneous Society with funding from the National Science Foundation. The project suffered from political and scientific battles, mismanagement, and cost over-runs, and the U.S. House of Representatives discontinued funding for the project in 1966.