will have an operating range of approximately 350 nautical miles at a cruise speed of 24 

 knots (12 meters per second). Two T64-GE-6B turboshaft engines of approximately 2000 

 horsepower each are used to drive 78-inch-diameter (198 centimeters), controllable and 

 reversible pitch propellers. 



SYSTEM SYNTHESIS 



With all component parts defined and demonstrated for various tasks, we will use 

 a recently completed, research-and-development task as a case history of the synthesis of 

 a vehicle for a particular application. The task chosen for this example is the need for 

 recovery of the solid rocket boosters (SRBs) used in the launch of the NASA space shuttle 

 vehicle into space orbit. After burn-out of the SRBs during the initial trajectory of the 

 shuttle, the 12- foot-diameter (4 meters) by 140- foot-long (43 meters) SRBs are jettisoned 

 and dropped into the sea by parachutes. Upon sea impact they float upright in a "spar" 

 mode with the nozzle opening down. The task was to provide a means to descend to the 

 depth of the rocket nozzle 100 feet (31 meters) and insert a plug so that the residual 

 water could be removed and the SRB tilted to a "log" mode for towing to a reclamation 

 site for reuse. 



The SRB dewatering system consists of a nozzle plug, control console, power 

 distribution subsystem, and umbilical cables. The remotely controlled, undersea vehicle 

 portion of this system, designated nozzle plug (NP), is 14 feet high (4 meters), from 2.5 

 to 7.0 feet in diameter (0.8 to 2 meters), and weighs 3300 pounds (1500 kilograms) in 

 air (figure 1 5). The NP was designed with a modular approach for ease of fabrication and 

 maintenance. The six modules can be described as follows: 



HYDRAULIC MODULE - The hydraulic module houses two, 15-horsepower, 

 electro-hydraulic pumps. These units provide the power to the four vertical and two 

 horizontal thrusters and the locking arms. The hydraulic system operates at 3000 pounds 

 per square inch (21 megapascals). 



TRANSITION MODULE - The transition module provides the transfer interface 

 for all pneumatic, electrical, and hydraulic functions. It is the structural portion of the 

 NP and has the thrusters and shock-mitigating bumpers mounted on it. The bumpers pro- 

 vide the means to seat the NP in the nozzle of the SRB prior to the deployment of the lock- 

 ing arms. Each bumper has a proximity switch and provides a signal displayed as a light on 

 the control console as the NP becomes firmly seated in the SRB nozzle. The framework 

 provides the conduit for the electrical power and the air supply from the ship. 



ELECTRICAL MODULE - The electrical module houses all NP control functions, 

 e.g., signal control relays, thruster controls, and sensors. 



INFLATABLE BAG MANDREL MODULE - The inflatable bag mandrel module 

 holds the inflatable bag used to seal the nozzle of the SRB during second-stage dewatering 

 (log mode). The bag is designed to inflate from 30 inches (76 centimeters) in diameter to 

 56 inches (142 centimeters) in diameter to seal the nozzle. The design is based upon the 

 Goodrich space saver tire concept. The mandrel also houses the dewatering pipe and syn- 

 tactic foam for flotation. 



LOCKING ARM MODULE - The locking arm module provides the NP with the 

 means to secure itself firmly to the nozzle once docking has been assured. The locking 

 arms are deployed by individual piston-cylinder arrangements. An over-center design 



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