During the early months of 1961, LOD took under consideration a third launch alternative, one that would eventually place men on the moon - the mobile launch concept.* The great advantage of a mobile launch concept lay in its promise of faster launch operations. With the fixed launch operation, e.g., SA-1 at LC-34, all rocket systems were mated and went through a thorough checkout at the pad. In the new scheme, LOD proposed to mate the vehicle and conduct these checks in an assembly building some distance from the pad. Only a brief prelaunch checkout at the pad would be needed to verify the rocket systems. Two digital computers, one in the launch control center and one on the transporter, would accelerate the checkout program and detect any change in rocket systems that might occur during the transfer to the pad. The computers were part of an automatic checkout system under development at Huntsville. By combining a mobile concept and automation, LOD leaders expected to reduce time on the pad from two months to no more than ten days.
There were other advantages to a mobile concept. Cape weather had corroded earlier rockets and might affect an exposed Saturn. An assembly building would provide cover for both the launch vehicle and the launch team. Having worked on rockets in the open, LOD leaders knew how difficult it could be for technicians laboring in wind, rain, and lightning at the upper levels of the space vehicle. Finally the mobile concept offered considerable savings in labor costs. Concentrating the work force in one assembly building, rather than on the ten pads projected for 48 launches per year, would reduce personnel requirements substantially.
The idea of assembling a rocket in a location remote from the pad and then moving it to the launch area dated back to World War II. At Peenemunde the German rocket team had transported V-2s in a horizontal attitude to a hangar where they were erected in checkout stalls. Following transfer to a rail-mounted static-firing tower, each V-2 was rolled out in a vertical attitude - sitting on its tail - for an engine calibration test and static firing. The missile received a final checkout in the hangar before being placed horizontally on a Meillerwagen for the ride to the launch site.25 Both the Redstone and Jupiter programs had employed a mobile launch concept with the rockets traveling from assembly building to pad in a horizontal attitude. LOD officials had hoped to use the same principle at LC-34, but time and money dictated otherwise. The Saturn C-1 test series permitted at least four months between launches, which was enough time to assemble and check out each vehicle on the pad.
Space planners outside NASA appreciated the merits of the mobile concept. The Air Force in 1960 had commissioned the Space Technology Laboratory to determine an optimum vehicle system for military use from 1965 to 1975. Entitled "The Phoenix Study Program," the work was subsequently completed by Aerospace Corporation and the Rand Corporation in June 1961. One of the recommendations of the study was an integration building where assembly and checkout could be completed before the vehicle was moved - sitting on its tail - to the firing area. It was estimated that pad time for the Atlas-Agena could be reduced from 28 days under the current operation to 5 days with a mobile system.26 In similar fashion, two Saturn C-2 launch studies, conducted by the Martin Company and Douglas Aircraft; concluded that Marshall's high launch rates would require a mobile complex.
* Concept vied with interface for first place In Cape Canaveral jargon, Meaning of concept ranged from the first "batting around" of an idea to its fruition in a multi-million-dollar building or procedure. While the authors have tried to limit their use of the term, they confess to ill success especially in the early days when LOD planners were dealing with many contingencies and termed each tentative plan a concept.
25. Zeiler interview, 11 Aug. 1970.
26. Memo for record, "Phoenix Study Program," 3 July 1961, p. 2; Aerospace Corp. News Release, "Titan III Management and Technology to Be Model for Future Systems" (Los Angeles, June 1965), p. 2.