...Or, alternately, that they are deep within one of those fancy star systems where high warp equals low sublight speed, much as in "Paradise Syndrome". Being deep insystem would be a prerequisite anyway, or else the comet wouldn't have a tail...
Sorry about the diversion. Under what sort of circumstances would you give the "status" of fuel in units of pressure? Or in fact units of weight times (per?) units of pressure, because "pounds pee-ess-eye" is redundant and expands into "pounds pounds per square inch"? Pressure would perhaps be the most appropriate for a fuel that is stored in compressible form, such as gas; there'd be no point in indicating the pressure of incompressible liquids, as it would tell nothing about quantity.
Or are we in fact hearing of the effects
of fuel when we get this status report? Perhaps there's a battery charged with phaser energies that can currently wrangle fifteen psi (or "pounds psi", whatever that is) of pressure out of the fancy pressure-making machine that is used instead of rockets in pushing the shuttle forward?
15 psi is rather little for propulsion applications, really, unless we're talking about a humungous surface area, much greater than any of the shuttle's cross sections. Surely any given square inch of the shuttle's bottom would have more than fifteen pounds of weight upon it, say?
...Except when you are already in freefall; Scotty might maintain an orbit with it (that is, nudge the perigee or peritaurus or whatever a little bit so that it doesn't plunge into the atmosphere that
badly), even if takeoff in fact takes fifteen thousand
...Or except when you are using the pressure in combination with gravity manipulation of some sort. Some sort of a slow hovering into orbit was apparently being planned anyway, rather than a rocketlike blastoff. Otherwise the precious seconds used hovering, with the cavemen clinging onto the hull, would have consumed a massive share of the total propulsion resources. All that calculating and leaving behind bodies would have been for naught if the launch depended on attaining of escape velocity with a minimum duration blast of thrust, like today's rockets do.
Oh, well. It all goes to show that in the case of "The Galileo Seven" we should not let writer intent hold us back in any way - because it's so evident there was no real writer intent involved in any of the technical details. Or even in many of the plot twists, alas. I seriously doubt anybody technologically oriented was consulted in any way in the writing or rewriting process.