Hello all, Ric here.
In Star Trek, warp drive is used to fold the fabric of space and move faster than the speed
of light by multiple factors.
However, this is impractical for general travel within a system and between planets.
Although intersystem warp jumps are becoming more commonplace with the precision needed
ever more attainable, Impulse drive is still the preferred option.
Colloquially, Impulse speed is used to describe any factor of travel at sublight speeds but
it is a particular technology within a ship.
The impulse engines can be supplied by the main warp core of a ship, using the matter-antimatter
reaction as fuel as most of the ship’s systems do, however its more common for them to be
supplied by their own fusion reactors.
These reactors too can be tapped for power when energy is drawn from the system.
These reactors can be anything that generates the required power and eventual electroplasma
required to create an impulse effect and as it needs less energy than a full warp reaction,
therefore impulse is often developed before warp drive, although not always.
It does require knowledge of manipulating subspace and the generation of subspace fields
which are a large component of warp travel, so the two technologies can go hand in hand.
In trek lore, Earth developed impulse drive sometime after the initial warp flight in
2063 in the late 21st century.
The fusion reactors are fueled by deuterium and converted into helium plasma.
This is then fed through subspace field coils, also known as the driver coils, which act
to compress and accelerate the plasma stream into a jet that is channelled through the
exhaust.
This creates a Newtonian reaction which propels the ship onward.
This does mean that there is an actual flow of energy being emitted from the impulse engines,
unlike warp drive which produces no such effect.
In addition to the compression effect, the impulse drives produce a subspace field around
the vessel to an extent which can aid in the movement of a ship, but additionally, this
can sustain a warp field for some time.
It is this effect that permits the saucer section of a Galaxy class ship to continue
coasting along at warp, after it has diverged from the engineering hull, but is not strong
enough to create its own warp bubble.
The Impulse drives have not changed design really since the 23rd century, with the perhaps
only factor being the downscaling of such drives.
One quarter impulse is the speed recognised as a standard travel velocity when inside
a solar system and full impulse is the equivalent to around one quarter lightspeed.
Impulse engines can be tailored for various roles with higher manoeuvrability on ships
such as shuttles and escorts, but even larger vessels can be unexpectedly nimble at sublight
speeds.
This does mean that at sustained high impulse speeds, time dilation is a factor, something
not usually dealt with in Trek travel, as warp negates this effect.
There can be a level of technobabble compensation with the subspace field of impulse drives,
but in apocrypha, approaching very high impulse for a long time can lead to some interesting
consequences as time passes slower for the travelling vessel.
There is not much else to say on impulse engines, except that there do exist some designs out
there, even within Starfleet that have no visible impulse outlets, or rely on a completely
different method of locomotion in space.
The Nebula class for example is a bit of a mystery, later version have added small drives
beneath the saucer, but initial designs had it lacking all impulse exhausts, with behind
the scenes justifications being that it relied far more on generating a subspace bubble and
effectively performing a sort of under-warp speed, warp effect to move, while the impulse
emissions themselves were shrouded for stealth purposes.
Whatever the justification, impulse engines are pretty much the go-to because it ties
into the manipulation of subspace to create the desired thrust, again that magic ingredient
being the answer to how things work in Star Trek.
Thanks for watching this quick breakdown on Impulse engines, I’ve been Ric and I’ll
see you later for another video, goodbye!