ebeck al] tining circuits in the timer jumetion box. A firing-set tester, which similares the vehicle, ami an EGAG telemeceriog siaulator are used to check operation aod circuitry of the external electrical systea. 8.2.5 Launcher Figure 8.4 sbows a launcher with a cwo-stage vebicle, loaded and ready for firing. The launcher has a single rail to provide 24 feet of guided travel. Two Launching slippers are used. slippers oo the vehicles. Figure 8.1 shows location of the laiumching Depending on the alritude desired, the slippers either remain on the vehicle or are jettissoed at the end of the Launcher. If they are left on the vehicle, identical slippers are attached diametrically cpposite to provide aerodynamic and static balance. Track and slippers are so designed thar the frooct slipper leaves the rail at the same time as the rear One. The same Lauocher may be used for either vehicle. The guidance rail is supported, for rigidity, on a strucrural pezber. The rail assembly is supported at the lower end of the triangular base of the lasacher, at the center, and at the upper end by two sets of legs. Elevation adjustsect is wade by changing the length of the support legs and by the addition of a fine-adjustment screw built into the base. made by pivoting the launcher base from left ro right. Azimuth adjustment is The structure is mounted on and is tied down to concrete pads at the corners of the base. A modifica- ction of this launcher uses steel tubing in place of fabricated legs and rail support. 8 Aiming of che launcher with respect to a known base Line is accomplished by use of an inclinometer to set the elevation angle and by an engineering transit used in conjunction witb a mirror system mounted on the rail to set the azicuth. Once the laun¢her bas been ained at a certain point, last mime changes to correct for winds can be quickly and easily nade. 8.2.6 Operational Aspects » . Preparation for firing «he instmment carriers consists of three separate paases: (i) preparation of tne iauncning sites, (2) erection of the launcners, and (3) preparation of the vehicles for firing. Preparation of the launching site included the laying of electrical cable and che pouring of concrete pads on which the Launchers are set. Pouring of