The main spaceship has two propulsion systems: The Boson Drive for intra-galactic travel, and Infinity Thrusters, which are used within a solar system, to travel between nearby planets, to achieve stable orbit, planetary atmospheric
flight, and landing.
The Ancestors had discovered a means to travel one light-year every ten years, the Boson Drive. What they had not discovered, was how to cover small distances in space, say from planet to planet. Some scientists were working on
how to scale down the Boson Drive for shorter journeys and intra-solar system travel.
They were caught in a conundrum. The Boson Drive only worked for speeds approaching or equal to light; it could not be scaled down to usable inter-planetary speed without losing all propulsion. Theoretically possible, in practice
the boson drive failed to deliver unless working within its optimal parameters; the range intra-galactic.
The breakthrough with inter-planetary engines was officially the result of disaster simulations. Mimicking expected war scenarios, one group disabled the main Boson Drive fusion reactor, expecting the secondary impulse regulating
drive to maintain similar thrust. It did not. It was designed to stabilise the output of the main Boson Drive. On its own, it was much less effective.
One technician realised this secondary drive could be scaled down, tritium and -13Q providing distant-planet intra-solar speeds, and deuterium with negative pentaquark bombardment, finite and close proximity positioning to the
nth degree. Combining both extremes within one module became a daunting task; like creating a microscope and a telescope as a single unit, not an easy thing to do.
After much experimentation, and greater theoretical study, the Infinity Thruster was devised. Originally, the name related to the diversity of subatomic particles that could be utilised to deliver thrust, their diverse combinations
providing progressive drive from one millionth of an inch per sub-second, to millions of miles per hour: (from Earth) the Moon ten minutes distant; Mars, less than one week; Pluto months bordering on years.
Once in service, the Infinity Thruster became redefined, due to its unique ability to place a spaceship to within a nanometer, in any three dimensional direction. However, to avoid danger to life, or compromising the ship,
all Infinity Thrusters are forbidden to fire anywhere near the ships hull; thus they must be paired at least, on opposite sides of the craft. All except the smallest craft (most Space Hoppers) have four, one at each theoretical
corner of mass.
It was enough, when put together, to allow speeds from rest, up by minute increments, to several light-days. The diameter of our solar system, from the opposing extremes of Pluto, is 21.9 light-hours (including the diameter of
the Oort Cloud [comet belt], 1.25 light-years). Velocities of light-months were possible, but the engine was not designed with those parameters in mind.
The practical outcome was the development of specific Infinity Thruster engines, which were relatively small in comparison to the Boson Drive. In Jack’s world, these would equate to small thorium reactors capable of powering a
town or submarine, a ship at sea.
Infinity Thrusters are infinitely adjustable, hence their name. They are ideal for docking with other spacecraft, obtaining precise orbit, or propelling craft within planetary atmosphere. The reason why they did not work well when
landing on Gaia, was because of Earth's great magnetic field; something previously unknown to the Ancestors. Their shields and drives used gravity wells to control atomic sub-particles, and these were severely disrupted by Earth’s
magnetism, as was the Core to a lesser degree.
Each main craft has eight Infinity Thrusters. Smaller craft like the Command Module have four, as do attack fighters. Space Hoppers have only two, but that is all they need. When a spaceship is in cosmic flight, normally only the
eight Infinity Thrusters of the main craft are used. Occasionally the four on the Command Module may be utilised, but this is rare, and used for space docking with another craft in orbit, especially un-powered satellites, like a