Moonport: A History of Apollo Launch Facilities and Operations|
Offshore Launch Facilities
As early as 1958, Livingston Wever, a member of the Army Test Office's Facilities Branch, had proposed the use of a modified Texas Tower* as an offshore launching platform for big rockets. Concerned about the Saturn's noise-making potential, Wever renewed his proposals in March 1960. Preliminary calculations, extrapolated from the noise levels measured during Atlas booster tests, indicated the Saturn C-1 would generate acoustical levels as high as 205 decibels at a distance of 305 meters from the launch pad. Peaks of 140 decibels, the threshold of pain, could be expected more than 3,000 meters from the pad. Wever was particularly concerned that the Saturn vehicle might emit a shock wave in the early stages of its trajectory (at heights from 600 to 900 meters) that would cause serious damage in nearby towns. He proposed to solve the acoustical problem by moving the launch platform to a structure 169 kilometers southeast of Cape Canaveral and 56 kilometers north of Grand Bahama Island. Wever noted that "because of the shallow waters and slight tide actions in the proposed area, it would not be unfeasible to construct a rugged, but unadorned, steel platform as large as 500 feet [150 meters] square, not only for immediate static tests of the Saturn, but also for actual launchings of the Saturn and large boosters of the future." Venting the rocket's exhaust into ocean water would save the cost of an expensive flame deflector. Wever also anticipated savings on the construction cost of the firing room (blockhouse).8
Wever's proposal met with mixed reactions at the Army Test Office's Facilities Branch. Although Nelson M. Parry, assistant branch chief, approved Wever's effort to circumvent blast and acoustical problems, Parry disagreed with the solution. Parry himself had been working on plans to develop artificial islands for several years. In a study completed December 1958, entitled "Land Development for Missile Range Installations," Parry proposed an artificial island large enough to contain a blockhouse, instrumentation, camera mounts, fuel storage, and launch pad and tower. His process involved pumping sand from the shallow waters just off the Cape. Parry estimated that an artificial island 1.6 kilometers square, with a mean elevation of 1.8 meters above high water, could be constructed for $9 million, This compared favorably with the $11 million cost of one Texas Tower in the early warning defense system. More important, the island would be a fixed platform; the Texas Towers swayed in moderate winds. Parry also objected to Wever's proposal to remove the launching site from the Cape to the Bahamas. This would introduce problems of telemetry, coordination, tracking, and camera coverage.9 Although supporting Parry's landfill procedures, Facilities Branch Chief Arthur Porcher considered the Banana River a better site for an island than the ocean floor off the Cape. He thought that any attempt to build up islands in the Atlantic would run into construction difficulties.10
In the Launch Operations Directorate, the job of evaluating offshore launch facilities fell to Georg von Tiesenhausen's Future Launch Systems Study Office. Tall, thin, and scholarly in appearance, von Tiesenhausen's looks befitted his "think-tank" role. His interest in offshore launch facilities dated back to World War II. Following the Allied bombing of Peenemunde in August 1944, von Tiesenhausen had recommended construction of floating pads to permit the dispersion of V-2 static firings. His plan had employed two barges, with the missile emplaced on cross bars.11 At the Cape, von Tiesenhausen assigned direct responsibility for studying offshore facilities to Owen Sparks, a former U.S. Army colonel and the team's unofficial technical writer. Sparks's first task was to prepare a preliminary survey for Debus.
Possible offshore Launch Facility, from a study by Owen Sparks in 1961.
Sparks's May 1960 report listed a number of launch problems for the Saturn program. These included the shortage of space at the Cape, safety hazards, and the problem of constructing an adequate flame deflector. The noise factor merited attention but was secondary. He suggested locating an offshore launch complex downrange in the nearest ocean area with a depth of 15 meters of water. He believed such a site would satisfy the requirements of blast absorption without unduly complicating range support. Since marine construction involved a great many problems, the design should be as simple as possible. Sparks recommended the use of a stiff-leg derrick combined with the umbilical tower to reduce gantry requirements, and the employment of a knock-down mobile service structure. Beyond provision for both static firings and launches any offshore facility should, he said, be expansible into a multipad complex.12
Sparks followed his first estimate with a preliminary feasibility study in late July 1960. His rationale for an offshore launching site had not changed. An evaluation of a half-dozen facilities favored the Texas Tower. This kind of facility, Sparks noted, could be placed in deep water where blast and sound posed no problems. Among other advantages, the offshore location would provide unlimited room for expansion, and fuel supplies could be kept on barges at a savings, compared to storage facilities on land. Sparks was no longer certain that the exhaust should be vented into the ocean - the resulting waves might damage the pad. Major disadvantages of a Texas Tower included the high cost of marine construction, the logistical problems of waterborne support for the facility, and the difficulty of providing a stable platform for handling vehicle stages and propellants. Sparks suggested further investigation of oceanographic conditions and their effects on launch structures, platform stability, and space vehicle requirements.13
* Named for their similarity to offshore oil rigs in the Gulf of Mexico, Texas Towers were skeletal steel platforms built in the mid-1950s by the Air Force The structure's massive triangular platform, supported by three 94-meter stilt like legs, provided space for three large radars and a 73 man crew, Three of these towers were placed about 128 kilometers off the northeast coast of the U.S. to provide early warning of air attack.
8. Livingston Wever, Support Instrumentation Div., to Porcher, Facilities Br., Army Test Off., AFMTC, "Addendum to Scheme for Offshore Launching Platform for Space Vehicles," Mar. 1960; Wyle Laboratories, Sonic and Vibration Environments for Ground Facilities - A Design Manual, by L. C. Sutherland, report WR68-2, 1968, pp. 5-21, 10-2.
9. Nelson M. Parry, Army Test Off., AFMTC, "Land Developments for Missile Range Installations (Preliminary Notes)," 30 Dec. 1958, p. 3; Nelson Parry to Porcher, "Offshore Launch Platform for Heavy Space Vehicles," 6 Apr. 1960.
10. Porcher interview.
11. Von Tiesenhausen interview, 29 Mar. 1972; Sparks interview; von Tiesenhausen, "Vorversuche fur Project Schwimmiweste," Electromechanische Werke Peenemunde, 11 Sept. 1944, typescript, von Tiesenhausen's private papers.
12. Poppet to Debus, "Offshore Complex," 6 May 1960.
13. MSFC, Preliminary Feasibility Study on Offshore Launch Facilities for Space Vehicles, by O. L. Sparks, report IN-LOD-DL-1-60 interim (Huntsville, AL, 29 July 1960).