We already have "maneuvering thrusters" at various locations all over the ship so we probably don't want to use that.
I envision those engines as a type of hybrid rocket/scramjet. They can function in pure rocket mode, but they can also take advantage of a combustible atmosphere at supersonic speeds for additional thrust. Technically they should not have a rotary compressor fan on the front and I would actually advise Dennis
to keep the center spike but eliminate the fan.
While all these technical details are largely irrelevant in a script sense--indeed, everyone involved has worked hard to avoid any undue obsession with technobabble--I do like to work out my own explanations for things behind the scenes, just to maintain some logical consistency if nothing else.
Propulsion-wise, I see Polaris
having three different systems. In order of least to most powerful, you have the maneuvering thrusters, then the booster engines, then the main engines.
The maneuvering thrusters are rather oversized on this ship class, which is fortunate since Polaris
is distinctly lacking in armor and other defensive capabilities and it's best defense is its ability to get out of the way.
The booster engines are used for takeoffs and landings, orbital maneuvering, and transitioning between orbital and interplanetary space.
The main engines are a high-tech aerospike variation. They are conventional reaction engines that work in tandem with the ship's artificial gravity/inertial compensation systems to MASSIVELY amplify thrust and exhaust velocity. These things are capable of driving the ship to a significant percentage of light speed very quickly using fractional amounts of fuel. They also produce a fairly lethal stream of relativistic particles hundreds of miles long, which is why they don't tend to be used in atmosphere or near orbit. Visually, I imagine each of the five engines in each cluster directing their exhaust toward the central spike, from which a pillar of blue fire shoots out like the lights on top of the Luxor hotel in Vegas, only about 10 times brighter.
At least, that's the way I
see it. Dennis
and the gang can take that for what it's worth as far as the effects sequences go.