How To Get From One System To Another

Starships have two major drive systems: sublight drives and hyperdrives.

---

Sublight Drives

All starships have sublight drives to propel them through space. (They're also known colloquially as realspace drives, since our dimension is known as "realspace.")

Sublight drives are used whenever a ship blasts off from a planet's surface to make a safe jump to hyperspace—such as when the Millennium Falcon blasted out of Mos Eisley Spaceport—and for trips between planets or moons within a system.

All starship combat takes place in realspace at sublight speeds. Some ships can also use their sublight drives for atmospheric flight.

The most common type of sublight drive is the Hoersch-Kessel ion drive. This powerful drive type can be adapted for any type of ship, from starfighters to capital starships, and it's manufactured under many different brand names. H-K drives can be configured to run on a wide variety of energy sources, the most common being rechargeable power cells or fusion generators.

(Most starships capable of planetary landings also have repulsorlift drives—similar to the ones used on vehicles—for maneuvers during landings.)

Sublight Benchmarks

While starships move at relatively slow speeds in orbit, they can achieve incredible velocities in open space. Here are some very rough guidelines for sublight travel times: • Five minutes to fly from orbit to a safe hyperspace jump point. • Half an hour to fly from a planet to one of its moons. • Two to six hours to fly from one planet to the nearest planet in the system. • (Two hours for relatively close terrestrial worlds; the upper limit is for flying between distant gas giants.) • 10 to 48 hours to fly from a star to the outer limits of the system, depending upon distance and hazards (asteroid belts, gas clouds, etc.). • (It takes about 15 hours to reach the outer limits of a "representative" system composed of a single yellow star and fewer than a dozen significant planetary bodies.)

Often, pilots find it's quicker to travel between planets by making a "micro jump" in hyperspace. While very precise navigation coordinates are necessary for this type of jump, such trips can be completed within an hour, compared to sublight interplanetary trips taking many hours.

---

Hyperdrives

Hyperdrives propel starships into an alternate dimension known as hyperspace, where it's possible to travel at many times the speed of light. Ships in hyperspace can cross the incredible distances between stars in a few weeks, days, or even hours.

When a ship jumps to lightspeed, the hyperdrive motivator engages the hyperdrive. The ship rapidly accelerates to and beyond the speed of light while crossing into hyperspace. (When a hyperdrive is deactivated, the ship automatically returns to realspace at the speed it had before the jump to lightspeed.)

Hyperspace is coterminous with realspace—if you head north in hyperspace, you are also heading north in realspace. Objects in realspace have a hyperspace shadow—a presence in hyperspace at the same location.

This means there's an inherent danger in traveling through hyperspace. Contact with an object's hyperspace shadow results in the instant destruction of the ship. (The object in realspace remains undisturbed.) Starships have mass shadow sensors to detect hyperspace shadows and shut down the hyperdrive to avoid collision, although these systems are not entirely reliable. While deep-space collisions are very rare, they also tend to be quite deadly.

Astrogators must plot safe paths around interstellar debris. Due to the incredible speeds achieved in hyperspace, the margin between safe passage and a collision is often only microseconds.

---

Nav Computers

To handle the overwhelming complexities of calculating hyperspace trips, most ships are equipped with navigation computers ("navicomputers" or "nav computers" for short). A ship's astrogator uses the nav computer to plot a safe trip along known hyperspace routes.

Nav computers hold a tremendous amount of data, storing coordinates for hyperspace routes and the locations of stars, planets, debris, gravity wells, asteroid fields, gas clouds, and other hazards. Ships without nav computers often use astromech droids—such as R2 units—to store astrogation coordinates.

(Pilots can try to make hyperspace jumps without navigation coordinates, but this is an incredibly risky proposition.)

---

Hyperspace Routes

Hyperspace routes are established paths through hyperspace linking major planets, just as roads link major settlements on planets. These routes are known to be safe, allowing ships to reach exceptional speeds.

As a route becomes well-known and its hazards are better understood, hyperspace journeys can be plotted with more precision at faster speeds; eventually, travel times between specific planets may actually decrease. Travel times can increase as well if obstacles drift into the hyperspace route.

In general, the greater the physical distance between planets, the longer the journey takes. However, even systems in close proximity may require roundabout hyperspace routes because of debris and other hazards.

Caution is always called for: the positions of over 90 percent of objects in realspace are unknown. The hyperspace shadow of anything larger than a boulder can destroy a ship, and there are countless such objects drifting undiscovered in deep space. There is always a slim chance that something has drifted into a hyperspace route.

Brave pilots may plot new routes in hyperspace, but this can be extremely dangerous. Scouts often use a series of very short micro-jumps, scanning ahead prior to each jump, eventually reaching a system after dozens of jumps. This is time-consuming and painstaking, but much safer than "blind jumping" into unexplored space.

Due to the complexity of astrogation coordinates, it's virtually suicidal to try to change course while in hyperspace. It's much safer for a ship to drop back to realspace to calculate a new hyperspace course.

---

Hyperdrive Multipliers

A hyperdrive is ranked by a class, or hyperdrive multiplier. The lower the multiplier, the faster the drive. • Most civilian ships have a Class Two (×2) or higher hyperdrive. • Many military vessels and starfighters have a Class One (×1) hyperdrive, which is twice as fast as a Class Two drive. • The Millennium Falcon has a Class 0.5 (×0.5) hyperdrive, making it one of the fastest ships in the galaxy.

Each hyperspace journey has a duration. Multiply the duration by the ship's hyperdrive multiplier to determine how long the trip takes.

Example: The freighter Thannik's Thunder has a hyperdrive multiplier of ×2. A trip from Tatooine to Bespin has a duration of 16 hours; it would take Thannik's Thunder 32 hours to reach Bespin. A ship with a ×1 hyperdrive would only need 16 hours. If the Millennium Falcon was making the same trip, its ×0.5 hyperdrive means it could reach Bespin in eight hours.

Hyperdrive Backup

Many ships have a backup hyperdrive. While very slow—some backup drives are ×10, ×15, or even higher—they can be used to limp to the nearest spaceport if the main hyperdrive is disabled.

---

Hyperdrives in the Game

Three things happen when a character wants to travel to a different system: 1. Pick the astrogation difficulty number. 2. Make calculations for the jump to hyperspace. 3. Determine the trip's duration.

---

1) Pick the Astrogation Difficulty Number

Astrogation difficulty can range from Very Easy to Heroic. Most trips have a base difficulty of Moderate, but difficulties can be much lower for easy trips (such as an Easy trip from Coruscant to Chandrila) or much higher for perilous routes.

For example, the Kessel Run requires at least five Very Difficult astrogation rolls due to the presence of the Maw Cluster, a conglomeration of black holes and gas clouds.

• Reduce the difficulty number by 1 for each extra hour added to the trip. ** Increase the difficulty number by 1 for each hour saved.

Example: Rhen is astrogating for a trip from Tatooine to Bespin. The trip will take 32 hours (Thannik's Thunder has a ×2 hyperdrive) and the difficulty number is 12 (Moderate).

Rhen decides to reduce the difficulty number. She's willing to add five hours to the trip—now it takes 37 hours—but the difficulty number is only 7.

Later, Thannik's Thunder is racing back to Tatooine from Bespin. This time, Rhen wants to save 10 hours, so the trip takes 22 hours. Unfortunately, her astrogation difficulty increases by 10: the new difficulty number is 22.

If the character's astrogation roll is equal to or greater than the difficulty number, the hyperspace trip goes off without a hitch. • If the roll misses the difficulty number by 10 or more, the ship cannot enter hyperspace and a new astrogation roll must be made. • If the roll misses by 1–9, the ship suffers an astrogation mishap.

---

2) Make Calculations for the Jump to Hyperspace

A character making an astrogation roll needs to make calculations for the jump to hyperspace. • One minute if using a well-traveled route or precalculated coordinates. • Emergency option: a character can try to jump in one round instead of one minute. The astrogation difficulty is doubled, and the character rolls each round until he either beats the difficulty number or suffers an astrogation mishap. • About half an hour between known systems. (Many captains calculate while still at the spaceport.) • A few hours if the ship has never jumped to the destination system before. • One day if the character doesn't know where he is (after a misjump), to determine position and compute new coordinates.

---

3) Determine the Trip's Duration

Trips between systems have standard durations: how long it takes a ship with a ×1 hyperdrive to travel from one system to another.

Tell the players the duration, since they can try to speed up their trip (with a higher astrogation difficulty), or they may decide to take longer to reduce the astrogation difficulty.

It's helpful to keep notes so you can use consistent durations between systems. These numbers can change during the game: durations may decrease as a route becomes heavily traveled, and can increase if hazards drift into the route.

Sample Durations (Guidelines) • Systems within the same sector: a few hours to a few days (1D). • Systems within the same region but different sectors: several hours to several days (2D). • Systems in neighboring regions: several days to weeks (2D). • Systems in distant regions: several weeks to months (2D). • Well-traveled route: reduce time by half. • Many random hazards: add +1D of the base time unit (days/weeks/months).

There is no known route that travels straight across the galaxy. Even the fastest ships, such as the Millennium Falcon, would take months to cross the entire galaxy—if such a route existed.

---

Hyperdrive Start-Up Sequence (Optional)

A ship's hyperdrive needs time to start up and push the ship into hyperspace. Find the ship's scale below and multiply the base time by the ship's hyperdrive multiplier. The total is the time required to make the jump.

For calculations made already in space, consider this time included in the time it takes to plot the jump.

---

Using Astrogation in the Game

The astrogation rules can be interpreted as needed for interesting play—the possibility of hazards drifting into routes allows you to set difficulties and durations as high or low as you want.

Acquiring astrogation coordinates can be a major part of the game—or as simple as running down to the local freighter pilots' guildhouse and paying a few hard-earned credits for the data.

Hyperdrive mishaps are best used as a plot device. If you don't have anything special planned, it's normally enough to cut to the arrival in the destination system and get on with the game.

Stopping Hyperspace Jumps

It can be very frustrating to a pirate to have a prize jump away while under attack (or frustrating for the gamemaster if they want the players' ship boarded). Remember: to jump safely, a ship must take time to calculate the jump: • 1 minute for well-known, well-traveled routes • Up to 30 minutes for most known systems • Several hours to calculate a jump to an obscure system

Hasty jumps can be reduced to a single round, but this doubles the difficulty.

Damage and Other Penalties

If a ship is: • Lightly damaged: add +5 to the base astrogation difficulty • Heavily damaged: add +10 to the base astrogation difficulty

In addition: • Ion cannon hits: add +5 to the base astrogation difficulty for every "controls ionized" result • Tractor beams: add the tractor beam's damage roll to the difficulty

All of these penalties are cumulative, and normal scale/damage guidelines apply.

Example

A pirate corvette (capital scale) is jumping a light freighter (starfighter scale). The corvette hits the freighter with an ion charge, ionizing its controls (two controls ionized results), and also hits it with a tractor beam, capturing it with a damage roll (plus 6D for the scale difference) of 33. The freighter captain decides to flee into hyperspace.

The gamemaster decides: • Base jump difficulty: 10 • Doubled for a hasty entry: 20 • +10 for ionization (two results at +5 each) → 30 • +33 for the tractor beam (including scale bonus) → 63 total difficulty

The captain has 5D in astrogation and rolls a fairly average 18. Obviously, the freighter is now in real trouble.

Notes

Emergency jumps still work fairly often against similarly scaled ships, since a good astrogator can probably roll within 10 of the difficulty and merely suffer a hyperspace mishap.

These guidelines also work well to keep an adventure on the gamemaster's intended course—if the encounter hinges on the prize vessel being neutralized and boarded, these options can help skew the scene toward that outcome.

---

Source: REUP:121