Astrogation Revised and Expanded

Astrogation is the science of navigating spacecraft through realspace and hyperspace.

Two tasks define astrogation: (1) determining present location, and (2) planning a safe and reliable means of reaching a destination. The former is performed by those skilled in astrocartography familiar with star patterns or automata. Astronav charts are used to map areas of space and could be used to plot courses through hyperspace. The plotting of a course is generally handled exclusively by astromech droids or navigation computers. The knowledge of one's whereabouts in space and other celestial objects was vital to navigating hyperspace, as incorrectly calculated jumps could mean a ship could collide with a planet, star, or other body.

Because of the danger of mass shadows (not to mention interdicting pirates), hyperspace courses had to be plotted with great caution. Very few beings other than powerful Jedi could react while traveling at many times the speed of light, and in any case conventional sensors and communicators cannot receive information faster than lightspeed. Even subspace sensors, which operate along an alternate dimension and propagate faster than light, cannot keep up with the vast speeds of hyperspace travel. Thus, precise advance knowledge of the celestial bodies along the way is necessary in the form of navigational computers. These devices, also known as nav comps or navicomputers by spacers, contain detailed star charts and the ability to make astronavigational calculations quickly from one point to another before a jump is taken.

Most star travelers use preexisting, well-known trade routes. This guarantees that interdiction by pirates and celestial bodies is kept to a minimum, help is close by in the case of a malfunction, and travel times can be reasonably predicted.

As a general rule, data for a particular route through hyperspace is available to anyone with access to the HoloNet—although that data might be out of date if the route in question is not frequently traveled by other ships. For example, the data for moving from Tatooine to Coruscant is likely to be very fresh, since ships make this trip on a daily or almost daily basis. On the other hand, the data for moving between two more isolated locations (such as Phindar and Umgul) is liable to be severely out of date because no ship has made this particular trip for several weeks or months. When traveling on hyperlanes the quality of data is considered to be no more than a couple of days old.

When traveling on hyperlanes the quality of data is considered to be no more than a couple of days old.

Traveling To (Difficulty Modifier)

Navigation Computer

A navigation computer, also known as an astrogation computer, navicomputer, navicomp, or nav computer, was a device that made the careful calculations necessary to navigate through hyperspace. Navicomputers would calculate data like the exact destination, the quickest and safest route to it, and the number of hyperspace jumps necessary. Most starships carried a nav computer of some sort, though some starfighters made do with only the astrogation buffer of an astromech droid. Smaller ships often possessed limited nav computers, capable of containing data for only a small number of jumps; larger ships had large dedicated nav computers capable of storing coordinates for nearly any foreseeable destination. Some nav computers were handheld. Smugglers tended to voice-print their navicomputers to hide where their ship had been.

All navicomputers contained the Galactic coordinates for all star systems in the known galaxy.

ᵃ Does not apply if ship also has a nav computer. ᵇ One can only cut the time by one fourth at best. ᶜ When trying to download information from a hyperspace beacon, the GM rolls one die. If the roll turns up "1", the beacon is broken or offline.

Astro Droids

Astromech droids, or commonly referred to as Astro droids, are a type of droid that serve as automated mechanics, performing a variety of repair duties and often serve as adjuncts or substitutes for nav computers on smaller starships. They are also able to use the mainframe of a larger ship to their advantage. A lot of starfighters rely on astromech co-pilots.

An astromech droid's primary purpose on smaller ships such as starfighters is as a backup or replacement for a nav computer; however, due to the limitations of each unit's astrogation buffer, an astromech can only hold a set number of hyperspace coordinates. They also provide in-flight maintenance and repair, and perform a number of routine functions so the pilot could focus on flying the ship.

Hyperspace Travel Times

While generally determined by the distance between two planets, hyperspace travel times between two locations seemingly close to one another could be drastically extended by the need to navigate around stellar hazards, such as asteroid fields and nebulae.

An example of this is the journey from Coruscant to Alderaan. In terms of distance, Alderaan was situated close to Coruscant—the former at approximately 5,000 light years from the Core, the latter at approximately 10,000. However, during the Imperial era, such a journey required roughly sixteen hours of travel due to a section of the route passing through a part of the largely-uncharted Deep Core, where navigation was difficult as a result of the gravity wells produced by the congregation of stars. Ironically, then, it was actually faster to get from Tatooine to Alderaan on the other side of the galaxy. In some cases, intragalactic travels could take days, depending on the distance between two planets and the obstacles between.

Traveling To (Base Travel Time in Hours)

ᵃ Apply this modifier first. ᵇ Apply this modifier second. ᶜ Apply this third. ᵈ Travel time cannot be reduced to less than one fourth of the base travel time.