ENGINEERING OPERATIONS AND SAFETY

	All main impulse engine (MIE) and saucer module impulse engine 
(SMIE) hardware is maintained according to standard Starfleet MTBF 
monitoring and changeout schedules. Those components in the system 
exposed to the most energetic duty cycles are, of course, subject to the 
highest changeout rate. For example, the gulium fluoride inner liner of the 
impulse reaction chamber (IRC) is regularly monitored for erosion and 
fracturing effects from the ongoing fusion reaction, and is normally changed 
out after 10,000 hours of use, or after 0.01 mm of material is ablated, or if ³2 
fractures/cmì measuring 0.02 mm are formed, whichever occurs first. The 
structural IRC sphere is replaced after 8,500 flight hours, as are all related 
subassemblies. Deuterium and antimatter injectors, standard initiators, and 
sensors can be replaced during flight or in orbit without the assistance of a 
starbase.
	Downstream, the accelerator/generator (A/G) and driver coil 
assembly (DCA) are changed out after 6250 hours, or if accelerated wear or 
specific structural anomalies occur. In the A/G, the normal need for 
changeout is brittle metal phenomenon resulting from radiation effects. 
During flight, only the accelerator assemblies may be demounted for 
nondestructive testing (NDT) analysis.
	Similarly, the DCA is subject to changeout after 6,250 flight hours. 
Normal replacement is necessitated by EM and thermal effects created by 
the driver coils. None of the DCA assemblies may be replaced in flight and all 
repair operations must be handled at a dock-capable starbase. The vectored 
exhaust director (VED) is serviceable in flight, requiring the least attention to 
deteriorating energy effects. All directional vanes and actuators may be 
replicated and replaced without starbase assistance.
	Operational safety is as vital to the running of the IPS as it is to the 
WPS. While hardware limits in power levels and running times at overloaded 
levels are easily reached and exceeded, the systems are protected through 
a combination of computer intervention and reasonable human commands. 
No individual IPS engine can be run at >115% energy-thrust output, and can 
be run between 101% and 115% only along a power/time slope of t=p/3.
	The IPS requires approximately 1.6 times as many man-hours to 
maintain as the WPS, primarily due to the nature of the energy release in the 
fusion process. The thermal and acoustic stresses tend to be greater per unit 
area, a small penalty incurred to retain a small engine size. While warp 
engine reactions are on the order of one million times more energetic, that 
energy is created with less transmitted structural shock. The major design 
tradeoff made by Starfleet R&D is evident when one considers that efficient 
matter/antimatter power systems that can also provide rocket thrust cannot 
be reduced to IPS dimensions.  Æ