Am is the colloquial (and technically incorrect) term for a “condensed” quad-axial space, accessible by certain life forms and organic technologies. Am is a form of “hyperspace,” in which travel and communication circumvent general relativity. Prior to the development of the Heirotus BTS, Am was only accessible via the will of humans possessing certain genetic mutations unique to navigators.
Motion in Am is possible through five dimensions – the XYZ axis, time, and “depth.” Space condenses along the depth axis while time does not, effectively enabling “realtime” FTL travel on a logarithmic scale.
Objects of a mass greater than the mass of the object traveling through Am exert a tidal pull on the object, drawing a ship “up” in proximity to stars or planets, and drawing the ship out into regular space if it gets close enough. Further, the lower the relative depth, the greater the mass influence of objects in real space. Given the spatial condensation effect of Am, human navigators have found it exceptionally difficult to submerge a ship beyond 0.2, as at this level space debris smaller than the ship starts to have a marked effect on performance – active Navigation becomes necessary to combat the mass effects of otherwise insignificant objects, causing turbulence. Relatively few navigators can sustain the act of active navigation (eg, constantly readjusting a ship’s depth while maneuvering on the XYZ axis), and as such the FTL “hard deck” is considered to be 0.4. Below 0.4 thrust and centrifuge-based methods of artificial gravity generation are impractical, as ship course correction becomes an active, near-continuous process. 0.6 is the preferred depth for civilian travel and placement of telecommunications hardware, as mass influence can be compensated for without specialized equipment.
The Heirotus BTS executes a synthetic Am insertion at a depth of 0.01, enabling a BTS-equipped ship to travel hundreds or thousands of light years in an instant. Successful navigation at this depth is made possible through mass amplification (eg the Sabrosa would acquire the effective mass of a small moon, negating the effect of most interstellar debris) and extremely accurate star charts. Even with accurate charts, the preferred method of BTS navigation is to aim straight at the plotted location of the intended destination, allowing planetary gravity to pull the ship out of Am.
In Transitional Voices it is mentioned that “Am” is an acronym for “Alcubierre Modulation,” which means the Jumpnet/Navigator combination and the Heirotus Biomagnetic Transfer System are different implementations of an Alcubierre drive.