Miscellaneous Society (AMSOC), to which Munk, Hess, and Roger Revelle belonged, took the idea under its aegis at a meeting at Munk's home—always characterized as a wine breakfast—and submitted a proposal to NSF in mid-1957 to explore the feasibility of drilling (and coring) a hole to the Moho. To give AMSOC a cover of respectability and fiscal responsibility, the National Academy of Sciences (NAS), at the suggestion of NSF, gave it an administrative home. NSF granted $15,000 (half the amount requested) and the work began, with Willard Bascom, an experienced marine engineer, as executive director. It was he who coined the name Mohole for the project. AMSOC was to provide both scientific advice and management.
One geophysicist, Maurice Ewing, Director of Lamont Geological Observatory, who became an AMSOC member by happening to be in the hallway of the Cosmos Club when AMSOC gathered nearby for a meeting, urged from the start that the single-site Mohole attempt should be preceded by coring at many places through the oceanic sediment cover, thought from seismic data, largely collected by ships of his institution, to be not more than about 1 km thick. He argued that not only would such an intermediate step provide experience in drilling in great water depths, but it would answer fundamental questions about the age of the ocean basins (permanent or young?) and the nature of the rocks below the sediments (harder sediments? volcanic rocks?). AMSOC, reflecting diverse views in the community, was divided on this, but decided temporarily to put aside Ewing's option and to keep the focus on the ultimate Moho target. The debate over this choice intensified over the life of Mohole, and the progressive ascendancy of the gradualists weakened the support in the scientific community for the one-hole approach.
Industry and Congress quickly rallied in support of the concept of very deep drilling, spurred by the public boast of the USSR to start drilling its own hole through the Earth's crust and thus to demonstrate its technological superiority over the United States once again, as had just been done with Sputnik (van Keuren, 1995). Riding on this wave, a preliminary notice of a proposal to NSF went forward from AMSOC to NSF in 1958 for $2.75 million, to be available in 1960.
The AMSOC proposal gave three possible types of drill sites: on a continent, on an oceanic atoll, and on the deep seafloor. The seafloor option prevailed, and for this a dynamically positioned, floating rig was deemed most feasible. The hardware part of the Mohole project got underway with some testing to see if a drill vessel could hold position in deep water during drilling, using a dynamic positioning system. AMSOC chartered an industry vessel, CUSS-I, which, after some preliminary tests in soft sediments of a Neogene turbidite basin in waters about 1,000 m deep west of San Diego, then drilled a hole 183 m deep in 3,570 m of water off the Mexican island of Guadalupe. The dynamic positioning scheme and the coring of both pelagic sediments and basaltic basement there were successful, opening the way to the more ambitious stage, a hole all the way to the Moho. The cost for this Guadalupe phase of Mohole was about $1.5 million. Enthusiasm was high and work to identify the best drill site proceeded. After extensive studies of existing geophysical records and some new survey work, a panel of geophysicists chose a site on the deep seafloor about 300 km north of the island of Oahu. All that was needed now was the actual heavy-duty drill ship.
NSF next opened the bidding for construction and operation of the Mohole drill vessel. Several consortia of experienced oil companies and shipbuilders submitted bids, but the nod went not to the lowest bidder, but rather to a company with no experience in drilling, the Texas-based major engineering and construction firm of Brown and Root. Partly because of the low evaluation score assigned to its presentation in the first round of bidding and its ascent to the top in several re-reviews, cries of unfair political influence by Brown and Root resounded. A Houston Congressman, Albert Thomas, chaired the committee that controlled NSF's budget and another Texan, L.B. Johnson, was Vice-President. A particular feature of the contract was that Bascom's AMSOC group (now organized as a private company) was to be incorporated into the Brown and Root operation, to keep the contractor oriented toward the scientific goals. Bascom soon jumped ship, declaring that the contractor was not paying much attention to his group's advice. Although AMSOC-NAS was still supposed to be providing scientific advice, AMSOC members were scientists fully engaged in their own projects and, absent Bascom's group, could not or would not assume Moho management responsibilities. The result was that NSF itself, rather than some academic entity, was managing the project.
The whole dreary tale of the bidding and rebidding process and of the subsequent delays, cost overruns (from original estimates of $14 million to later estimates of about $160 million) and final failure of the project has been recounted in detail, for example in Solow's 1963 article in Fortune magazine. After the expenditure of about $57 million, Congress (Representative Thomas, chairman of the committee controlling the NSF money having just died) denied further funding and NSF had to abandon Project Mohole, with no ship built or any ocean crustal hole drilled. One hole, about 300 m deep, was drilled on land into serpentinite (altered mantle?) near the coast of Puerto Rico, as a test of drilling tools. NSF learned the hazards of attempting management by NSF rather than by contractors with roots in the academic community concerned directly with the scientific goals of the project.
In hindsight, given what we know now from three decades of drilling experience in crustal rocks, it is highly unlikely that drilling at the candidate Moho site near Oahu would have penetrated more than a small fraction of the thickness of the oceanic crust. By 1965, the Moho, as a near-term scientific objective, gradually faded from the agenda of working scientists.