Main / Astrogation

FAQ - Jump Travel

Astrogation

quick add to remember - Jump Emergence Watch typcially starts at the earliest potential emergence and continues through. The Astrogator is expected to be the primary person standing that watch. \

This skill is for plotting the courses of starships and calculating accurate Jump Travel routes. A skilled Astrogator can affect the length of time spent in Jump, where the ship emerges in the target system, and synchronize the ship with the System Time of the arrival point. Because this is a highly technical and skilled position Astrogators typically command a monthly salary of Cr5,000. Typically, someone with the Astrogation skill is required on all jump capable ships in normal circumstances. In crowded Systems an Astrogator can assist the Pilot in plotting efficient courses to various locations in the system. Some Astrogators develop a reputation for the preciseness of their Jumps with exclusive clubs for like-minded Astrogators to share information and tips. There are sectors that have competitions and wagering on an Astrogator's skills.

In the Imperium the Imperial Scout Service mapping branch is in charge of maintaining Astrogation Charts for known Charted Space including the frontier areas that are visited less frequently. Often before docking visitors to a Starport must present a bill of clean health; papers of starship registration, crew and cargo manifests, and astrogation data from the last four jumps. One of the rarer Sophonts in Charted Space are the Caprisaps {a nomadic people originally uplifted from Terran goats}. They frequent the space around the Vilani-Vargr border, mining, trading and employed enough by both species to be considered a neutral buffer between the two. They are natural Astrogators starting with Astrogation 0 for free.

Examples of Modifiers for the Astrogation Skill Check

All jumps need to be plotted. When travelling along routes in charted space this is a Simple (2+) or Easy (4+) task check (1D x 10 minutes, EDU), modified by the jump distance (thus, a jump covering 4 parsecs gives DM-4 to the check). If the check is failed, then the astrogator must plot the jump again. Astrogation can be done in advance (a jump is normally plotted while the ship is travelling out to the hundred-diameter distance). If an Astrogator takes additional time to check their course they get the appropriate bonus DM. However, in Combat there is often not enough time to compute the full Jump plot. This gives a -2 {Difficult} modifier to the skill check.

If the skill check is failed, then the ship Mis-Jumps.

Astrogation Details

The Astrogator is aware of an incorrect Jump plot after inputting into the computer. With this feedback the astrogator and can re-compute the course from scratch. Astrogators know not to trust charts if risking a jump to an empty space, as even a small error could leave the ship fatally stranded.

A ship’s computer is a smart tool, assisting crew in their tasks or doing tasks on their behalf. Some ships take this to extremes with software packages that provide a virtual crew to handle piloting, sensor operation and gunnery, along with drones to handle tasks such as engineering that require moving around the ship and interacting with its systems. Astrogation must still be done by a sophont for truly accurate Jumps but some small ships can theoretically fly without an astrogator.

As any astrogator will tell you, no two jumps are the same. The crew should remove from duty any astrogator who tries to repeat the exact same process for a new jump as a previous jump, believing that because it worked once it will work again. Nonetheless, any given jump can be broken down into five broad steps:

Tracking and Predicting Jumps

There are times that an Astrogator will be asked to track a ship that is leaving a system to predict where it is jumping to.

The easiest way to predict a ship’s destination is to require vessels to use part-prepared jump plots. This has the advantage that all ships from a particular port will arrive at a specific arrival point. The ‘point’ in this case is a volume of space defined by standard jump variance. A ship claiming to be from that port that does not arrive in the expected emergence zone will attract attention, although the reasons may be entirely innocent. This only works if there are well established protocols such as many of the most populated systems in the Imperium.

If the ship has calculated its own jump plot, its destination has to be predicted using a mix of sensor data and detective work. The vessel’s known capabilities will rule out some destinations and destinations that are masked or otherwise not available can also be ignored. If the vessel is presumed to be headed for an inhabited world, its destination can be SIGNAL deduced with a reasonable chance of success. If the destination must be determined from jump parameters alone, the task is much harder. The emissions of the drive must be analyzed to gain an indication of the destination, giving a result that might be anything but precise. Matching parameters against partial plots for known worlds within reach can give a high-confidence result but the target ship might have jumped to any point of any star system within range. Parameter Matching requires 3D minutes per world or volume of space.

An Average (8+) Astrogator check is made and if successful the analysis indicates if there is a match or not. This will confirm if the target ship jumped to a particular world or indicate that it did not but yields no other information. Full Analysis requires 2Dx10 minutes. An Average (8+) Astrogator check must be made. If it is failed, the analysis produces no useful results. If it is successful, roll 2D and add the Effect of the check.

On a probable result, the Referee should secretly roll 2D. On 9+ the analysis was wrong and a false conclusion has been reached. On a certain result the Referee should inform the Travellers of the destination but may still wish to make a secret roll just to keep them wondering if they are about to embark on a wild goose chase.

Mis-Jumps

Mis-Jump is a generic term for when a Jump has not occurred as expected. They can be classified as a Bad Jump, a Very Bad Jump, or a Failed Jump. Normal Jumps rarely result in a Mis-Jump when normal precautions are taken. At worst a Bad Jump might result as an effect of sloppy or hurried calculations. A Very Bad Jump is very rare, and a Failed Jump can be catastrophic to the ship.

A Bad Jump typically produces a feeling of dislocation and confusion, often accompanied by nausea and headaches, at the moment of entry and some time before emergence. Everyone aboard the vessel must make an END and INT check. One of these checks is at Routine (6+) difficulty and the other at Difficult (10+) difficulty level. A Traveller can choose which check is taken at each difficulty level.

The END check determines if physical effects are present. These include nausea and possibly vomiting, plus often a blinding headache. If the END check is failed, all checks the Traveller attempts are subject to a DM equal to the Effect of the failure for 2D hours after entry into jump, and again after emergence. An Effect of -6 or worse indicates the Traveller is incapacitated; unconscious or wishing he was, for 2Dx30 minutes after which a DM-6 applies on all checks for the following 4D hours.

The INT check determines if psychological effects are present. These typically include unease, irritability and paranoia, but in some cases can lead to a complete breakdown. Anyone who fails the INT check will be irritable, nervous and generally out of sorts for the whole duration of the jump. This manifests as difficulty in concentrating as well as a tendency to be on edge which often makes interactions with other Travellers unpleasant. DM-2 applies to all checks associated with mental or interpersonal activities. The Traveller will be visibly on edge and may appear to be behaving suspiciously or in a paranoid fashion. Memory lapses, covering a few minutes to an hour or two, are also possible. An Effect of -6 or worse indicates the Traveller is suffering from serious mental effects. These manifest as acute paranoia, blackouts and hallucinations. A Traveller in this state might harm themselves or someone else or take a potentially dangerous action such as locking a hatch that the rest of the crew need to access a critical area. Psychological effects last throughout the jump and for 1D days afterward.

BAD JUMPS Bad jumps are not confined to Misjumps – some systems are notorious for unpleasant jump effects, for no known reason. In other cases, a hurried insertion or decayed jump plot may also merit a bad jump. A decayed plot is a set of jump parameters generated for use under slightly different circumstances (for example, the ship might have significantly changed its speed and heading since the plot was generated) or a plot that is more than 3D hours old. Jump plots are sufficiently complex that they decay quickly. At first this will cause a bad jump; severe decay in the plot will cause a misjump.

If the jump variance rules are in use, ill-effects will be felt by the crew and passengers if either Variance table indicates a Bad Jump. If both tables indicate a Bad Jump, the effects will be magnified as per Very Bad Jumps.

VERY BAD JUMPS If both variance tables indicate a Bad Jump, or the ship misjumps, the effects are magnified. Both checks (INT and END) must be made as above, but DM-2 applies to both. In addition, there may be other effects on the ship and its passengers. On the Very Bad Jump table, DM-4 applies if Bad Jump was indicated by both variances table. DM-2 applies if the Very Bad Jump was caused by precipitation due to hitting the 100-diameter limit. Normal misjumps are rolled without DM. DM+2 applies if the ship jumped whilst under significant gravitational effects (typically this means jumping within the 100-diameter limit of an object). DM+4 applies if the ship jumped whilst under serious gravitational effects (typically this means jumping from within the 10-diamerter limit of a planet or other body). Only one modifier is used – the referee should use the highest applicable to the ship.

Very Bad Jump - 2D Effect

Jumpspace intrusions are extremely serious. The ship’s jump field becomes unstable, allowing pockets of jump space to enter the ship. This will destroy any matter it encounters, such as bulkheads, wiring and Travellers. The intrusions are usually stable, so will be limited to a particular location for the whole of the voyage. However, additional intrusions can occur at any time or existing ones may spread. A ship may be slowly consumed by the intrusions, with Travellers forced to retreat to unbreached compartments and hope the ship emerges into normal space before it is lost entirely. A ship suffering jumpspace intrusions suffers damage equal to 2D-2 as a percentage of its Hull per day. This matter is completely destroyed, requiring a major rebuild if the ship survives. A severe intrusion consumes 2D+10% of the ship’s Hull per day.

Failed Jump A Misjump occurs if the sum of the Effect achieved by the astrogator and engineer is 0 or less. This means that if one fails their check but the other makes theirs by a greater margin, the Misjump is averted, though in this case the effects of a Bad Jump should be imposed. If the sum of the Effects is 0 or less, a Misjump has indeed occurred, and if both checks are failed a Serious Misjump has happened. All Misjumps are accompanied by the effects of a Bad Jump, and Serious Misjumps are accompanied by the effects of a Very Bad Jump. This is in addition to the effects noted on the Misjumps table below.

If a Failed Jump occurs, roll 2D on the Misjumps table below using the combined Effect of the Engineer and Astrogation checks as a DM.

Failed Jump - 2D Outcome

Starship Operators Handbook

This practice extends to clock synchronisation. Standard transponder beacons, part of traffic control in most systems, broadcast local time so incoming ships can adjust their clocks upon jump breakout. Where these beacons are not present, standard astrogation software can deduce current time to within a second as part of confirming the ship’s arrival. Ships that do not jump for a while typically automatically sync their clocks every week, before even a millisecond’s drift can set in.

ASTROGATION In theory, jumps happen in straight lines with no arcs. Astrogation is simply a matter of calculating a straight-line shot at a distance of parsecs. If only things were so easy. On rare occasions, they can be this simple but usually there is some rogue body in the way, sometimes entire solar systems. Jump into them and you wind up stopping at their 100D limit instead of the destination’s. Detour around them, and the ship is off course. The solution is to deviate a tiny fraction of a degree, hitting perhaps 100.01D but no closer to take advantage of spacetime’s slight bend, magnified by jumpspace, in the presence of strong gravity fields. Unbend spacetime and the line of travel is ‘straight’ but is rarely how observers in realspace apply that term. This manoeuvre relies on nearperfect knowledge of every rogue body enroute to a destination, knowledge that – thanks to lightspeed limitations – is virtually impossible to acquire. Projecting these objects forward in time can result in some approximation but requires complex n-body simulation to achieve anything close to an accurate result. These skillsets translate well to in-system navigation as well; SDBs may carry astrogators to plan an interception course. All told, a successful jump plot can require keen knowledge of technical software, a working knowledge of astrophysics, a willingness to take in uncountable variables and to utilise an intuition honed over years. This is why astrogation takes training.

Standard Jump Control software packages automatically calculate this arc, taking predictive data starting from the last known coordinates of any worlds in the destination system and projecting their trajectories to a safe emergence. Part of the finesse of an astrogator’s job is compensating for these unknown or semi-known variables, as explorers did not always finely map interstellar space and most rogue planets, planetoids and comets are almost undetectable. Charts will show reported navigational hazards as well as data gathered from long-range telescopic observation from ports but any jumping ship risks arriving at an uncharted mass without a skilful astrogator. Machines are not good at this part, although chance favours them occasionally.

Ships without trained astrogators can use ‘jump tapes’, pre-plotted astrogation solutions that will fly a specific ship from one system to another, good for only a limited time, typically a week or less from manufacture. After that time, conditions in and between the systems may have changed enough that the ship needs a new solution. One downside of relying on jump tapes is that the ship can only jump to destinations that have jump tapes available.

High Guard

ASTROGATOR Astrogators are only required on jump-capable spacecraft. The astrogator is responsible for keeping track of where the Travellers’ starship is and where it is going. Jump drives enable Travellers to get from one star system to another and the astrogator’s main job is to make sure that they get to their destination safely. The course is plotted with the aid of a starship’s astrogation computer but the astrogator must make key decisions regarding the departure point, jump distance and estimated arrival point. In addition, qualified astrogators understand astronomy and jumpspace physics well enough to calculate the basic course data provides information about their surroundings in normal space. When coming out of jumpspace, the first question the astrogator wants answered is ‘Where am I?’. The astrogation computer analyses data from the sensor arrays, library program, recorded data from the flight computer and data gleaned from local satellite arrays and starport control, when available. The engineering interface enables the astrogator to submit their course to the ship’s engineer who tunes, prepares and engages the jump drive to make the journey.

When one is in the Regina system and planning on a jump to Yori – a mere two parsecs away – the astrogator has access to an immense amount of data that is used to ascertain where the ship is and where it is going with pinpoint accuracy. There is less data for backwater systems, whose available resources might be slim and none but the starship’s computer and sensor array can be used to perform a basic system survey within hours, giving the astrogator what is needed. Once a spacecraft is in flight, the astrogator sees a display of ‘known objects’, things that are expected to be present in the current star system. These include orbital starports, satellite arrays, near-planet objects such as asteroids and comets and other things for which there is a historical record of existence and location. Sensor array data provides a plethora of information, which is fed to the astrogation computer that then guesses in advance what the astrogator might want to do next, providing scenarios for a series of potential courses.

When flying ‘nap-of-the-earth’ to a destination on the other side of the planet, astrogation data provides an array of choices for the pilot to make. Weather patterns are obtained from local data sources, if any, or predictions based on the meteorology of the local region or that which the computer observed during planetfall. This is where Astrogation gives way to the Navigation skill. Once within nap-of-the-earth range, Navigation is used to accurately get Travellers to their destination.

When taking the ship into orbit, the astrogation computer checks in with the local starport, if present. The computer checks the starport’s data and places all known objects in cache, not displaying them until after their presence is confirmed by sensors. Once the sensors detect new ships or other objects, the computer updates the local traffic display and presents it graphically to the astrogator. Known or expected objects have a greater amount of data available. New objects are presented with whatever is known: transponder IDs, power signatures, basic size and shape coalesce into a presentation that evolves as the sensors and other data sources obtain more information.

Jump drives are primarily tuned for travel between gravity wells, deftly staying outside of the 100-diameter limits of stars, planets and other objects. Jump courses rely upon those gravity wells as points of contact. Making jumps into deep space – empty hexes on a starmap – far from any discernible gravity wells, is a risky undertaking. Experienced astrogators learn how to do it by triangulating: they anchor their desired destination point to the last visited gravity well and known far-off gravity wells that are one or more parsecs away. The calculations for deep space jump exits are complicated and missteps can be hazardous. If the numbers are wrong, the ship may exit jump in the wrong spot, making it difficult to recalibrate and make the next jump.The astrogator role is the only one that most species in Charted Space do not automate. Astrogation is more than just starmaps and complicated mathematical calculations. It is an art form.

{WBH} The Effect of the Astrogation check determines the precision of arrival at the destination. A destination location is computed as ‘diameters’ if the target is a Size S dwarf planet or larger object. Otherwise, the ‘planned location’ is a point in space near an asteroid, comet or artificial body and distance is in kilometres.

Empty Hex Arrival Variance Effect Variance Diameters (Size S+) Kilometres (planned location) 6+ On target 100 within 1 kilometre of location 4–5 Excellent 100 + 1D 1D kilometres from location 2–3 Good 100 + 2D 2D kilometres from location 1 Acceptable 100 + 4D 2D × 10 kilometres from location 0 Poor 100 + 1D × 100 2D × 100 kilometres from location Negative Failure -1000 x Effect -1,000 x Effect kilometres from location

THE JUMP PLOT Plots can be created well ahead of time but degrade for reasons that are only partially understood. It is generally accepted that the relative movement of objects in the universe – planets in their orbits and asteroidal debris in the target or departure system – will render a plot less accurate over time. What continues to puzzle scientists is that even building in a predicitive model for these variables does not prevent a plot from degrading over time. It may be that this is simply because no model can possibly include every rock or dust cloud across a couple of parsecs but there are those who claim other factors are at work.

For this reason, pre-prepared jump plots – called ‘course tapes’ for reasons now lost in antiquity – are much less accurate than a plot created by a ship’s astrogator just before jump entry, although it is possible to prepare a ‘plot estimate’ and add the last variables just before jumping. This practice is common aboard ships that expect to make a particular jump, and part-prepared jump plots can be obtained from some starports. This service is often provided free by Class A and B ports but unlikely to be available elsewhere. The port benefits from greater control over exactly where in the system ships jump from and often has an agreement with nearby destinations about emergence points. A ship using a part-prepared plot cannot falsify its destination, which is beneficial for general security and reduction of illicit activity.

Preparing a jump plot takes 1Dx10 minutes and requires an Easy (4+) Astrogator check with a negative DM equal to the jump number in parsecs. Using a part-prepared plot reduces the difficulty to Simple (2+) and time to finalise the plot to 1Dx2 minutes. Naval ships with multiple astrogators often begin preparing jump plots to likely destinations as soon as they arrive in a system and any ship expecting combat will have an emergency jump plot kept at a near-final state. This requires constant updates and absorbs the attention of an astrogator but can save a ship that is taking a pounding.

Companion JUMP VARIANCE When a jump is plotted, the astrogator attempts to refine all of the vastly complex calculations and variables involved into a ‘jump plot’ that will bring the vessel out as close to the 100-diameter limit of the destination as possible. The ship’s engineer then attempts to implement the plot in such a way as to get as close as possible to the astrogator’s theoretical model. Jump navigation is not a 100% precise science however, and there will always be some variance. Assuming the plot from the astrogator and entry into jumpspace set up by the engineer are both good (both skill checks are made) then the vessel will arrive a safe margin short of the 100-diameter emergence limit after approximately 160 hours +/- 20 hours. The Distance and Time Variance tables give typical jump characteristics. The Effect of the astrogator’s skill check to set up the jump plot is used as a DM on the Distance Variance table. The Effect of the engineer’s skill check is used as a DM on the Time Variance table. In general, the better the plot and jump entry, the closer the jump will be to baseline parameters. A model jump of exactly normal duration and emergence is at 105 diameters to create a margin of safety, though a very good plot can bring the ship out at exactly the 100 diameter limit and shave some time off the journey.

Astrogator’s Effect 2 or less 110-3D diameters. Bad Jump 3 110-2D diameters. Bad Jump 4 105-1D diameters. Bad Jump 5 100+2Dx10 diameters. Bad Jump 6 100+2Dx5 diameters 7 100+4D diameters 8 100+3D diameters 9 100+2D diameters 10 100+1D diameters 11 100+D3 diameters 12 or more 100 Diameters exactly

If the variance indicates the emergence point is closer to the target than the 100 diameter limit, the vessel is precipitated out of jumpspace at the 100 diameter limit, suffering the effects of jump precipitation on page 141.

4 8D Hours. Bad Jump 5 6D Hours. Bad Jump 6 5D Hours 7 4D Hours 8 3D Hours 9 2D Hours 10 1D Hours 11 1D3 Hours 12 or more 160 Hours exactly Variance can be long or short. Roll 1D: Odd indicates that the jump is long in duration, even indicates it is short.