Astrogation, short for astronavigation, is the planning of a route through space and the actual navigation of spacecraft, either subluminal maneuvering in interplanetary travel or the calculations used to perform slipstream space jumps in interstellar travel.
In the United Nations Space Command, UNSC Astronavigation is the organization responsible for creating and maintaining astrogation data. After the start of the Human-Covenant War, this data became a major security risk as the Covenant could potentially use it to pinpoint the location of human colonies and Earth. This prompted the enactment of the Cole Protocol, which established various measures to prevent NAV data stored on starships or other locations from falling into Covenant hands.
In context of spacecraft maneuvering in conventional space, several UNSC Naval commanders have been remarked as being particularly proficient in astrogation. Captain Jacob Keyes was credited as a skilled astronavigator, due to his daring maneuvers, particularly the "Keyes Loop" he performed during the Battle of Sigma Octanus IV. Admiral Preston Cole was also renowned for his skills in using effective tactics, including gravity-assist maneuvers, in space battles.
While most other operations involved in operating a spacecraft, including maneuvering in normal space, can be performed by a human pilot, the successful execution of slipspace jumps requires a navigation computer or a shipboard artificial intelligence. Due to the unpredictability of human drives, dedicated slipspace guidance beacons are sometimes used to provide navigational reference points when a coordinated and accurate slipspace transit is necessary.
Despite the necessity for a computer to perform the jump itself, UNSC Navy personnel are taught the basic calculations involved in a slipspace jump, known as Shaw multivariate calculus. In the late 25th century, then-crewman apprentice Preston Cole gained recognition for coming up with a new way to calculate Shaw-Fujikawa jump parameters. There have been instances of individual ship captains performing slipspace jump calculations on their own, usually to execute a nonstandard or experimental jump, but the results of these have often been disastrous or uncertain, including Admiral Cole's possible in-atmosphere jump during the Battle of Psi Serpentis. When commandeering the stolen Insurrectionist craft Beatrice, Dr. Catherine Halsey plotted a slipspace exit vector through a saddle point in an imaginary mathematical plane involved in the jump function, allowing the drive to recapture the particle accelerator energy in its plasma coils, although this maneuver introduced a noted risk of coil overload.
A slipspace jump path must be computed through a pattern of superfine quantum filaments which are distorted by gravity. Prior to the UNSC's discovery and implementation of superior Forerunner drive technology, human slipspace technology lacked the resolution to compute a path through the warped filaments near significant gravity wells, such as that of a planet. The Covenant's superior slipspace technology allows them to compute jumps with far greater precision and stability, owing to their reverse-engineering of Forerunner relics. The major difference is resolution: a Covenant ship is able to calculate abstractions in the lattice of quantum filaments on a far smaller scale, allowing an AI, for example, to compensate for the warped spacetime within a gravity well and perform a jump whilst using minimal energy. Following the Human-Covenant War, a number of UNSC ships, most notably UNSC Infinity, have been fitted with Forerunner drive technology, granting them near-perfect jump accuracy and far greater slipspace velocities than before.
List of appearances
- Halo: The Fall of Reach (First appearance)
- Halo: First Strike
- Halo: Ghosts of Onyx
- Halo: Contact Harvest
- Halo: Evolutions - Essential Tales of the Halo Universe
- Halo: Blood Line
- Halo: The Fall of Reach (2010), Adjunct
- Halo: The Fall of Reach, page 135 (2001 edition)
- Halo: Ghosts of Onyx, page 155
- Halo: Evolutions - Essential Tales of the Halo Universe, "The Impossible Life and the Possible Death of Preston J. Cole", page 483
- Halo: Contact Harvest, page 96
- Halo: Blood Line, Issue 1
- Halo: Evolutions, "The Impossible Life and the Possible Death of Preston J. Cole", page 477
- Halo: Evolutions - Essential Tales of the Halo Universe, "The Impossible Life and the Possible Death of Preston J. Cole", page 426
- Halo: The Fall of Reach, page 20
- Halo: Evolutions, "The Impossible Life and the Possible Death of Preston J. Cole", page 484-486
- Halo: Ghosts of Onyx, page 152
- Halo: First Strike, pages 85-86 (2003 edition)
- Halo: The Thursday War, page 247