Service valve and use of same in reaction control system

Various types of valves are disclosed, as well as the use of the same in a reaction control system for space travel vehicle applications. Multiple functions are provided by one of these valve designs by providing multiple flowpaths through the valve. An inflow and outflow tube of this multifunctional valve are fluidly interconnected with first and second chambers, respectively, within the valve. These first and second chambers are isolated from each other by a barrier assembly which may be "removed" at the desired type by a barrier rupture assembly to provide one of the noted multiple flowpaths (i.e., the inflow tube, the first chamber, the second chamber, and the outflow tube). A separate service port is fluidly interconnected with each of the first and second chambers, and a separate service valve may be disposed in each of these service ports to provide additional flowpaths for the multifunctional valve. One flowpath which exists prior to a rupturing of the barrier assembly includes the inflow tube, first chamber, and its associated service valve. Another flowpath which exists prior to a rupturing of the barrier assembly includes the outflow tube, second chamber, and its associated service valve. Another valve disclosed herein is a service valve for providing for a flow/no flow condition within a fluid system. This service valve includes a valve body and a valve stem which is slidably disposed within a bore within the valve body. The valve stem may be moved between at least two positions to terminate flow through within the valve body and to allow flow through the valve body, respectively. The service valve is configured so as to be resistant to side loads and provides redundant seals on redundant sealing surfaces. In this regard, the service valve includes at least three longitudinally-spaced radial seals between the valve body and valve stem, which are appropriately sized and oriented relative to each other to provide the desired functions.