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While some believe that space is an empty void, there are many hazards that can affect space travel, either to the benefit or to the detriment of a spacefaring vessel and its crew. Most environmental hazards in space can be avoided, but not all, and when moving through the Void or hyperspace, unless the route is known and the vessel’s pilot is prepared, vessels may randomly stumble across an environmental hazard that could put their journey, their vessel, and their crew at risk.

Random Hazard Encounter Chances

Hazards may be encountered randomly or simply at the GM’s discretion. Should the GM wish to use the random encounter tables listed below, they are provided for that use. These encounters typically occur randomly while in hyperspace as determined by the GM.

If a field is encountered, a separate table is included to determine the overall size of the field.

Hazard Examples

Asteroid Field/meteor Shower

Asteroid fields are largely stationary groupings of rocks and ores that float about in space. They are divided into two primary classifications; passive and active. Passive asteroid fields are older, more stable fields that often are arranged into asteroid belts (though not exclusively so), and there is very little movement among the asteroids. This is not to say that they do not present a danger, but active fields are far more deadly. Active asteroid fields are those where the asteroids are randomly moving rapidly throughout the field, smashing against one another and crushing anything unfortunate enough to be caught within their boundaries.

Meteor showers are much like active asteroid fields, but the rocks are traveling in a specific direction. Meteor showers can sweep across space lanes, or can even shower down upon planets. Fortunately, most of the stones in a meteor shower burn up in the upper atmosphere of a planet, but those that get through often cause great devastation.

Asteroid fields or meteor showers that occupy hexes of space between or surrounding vessels in combat, grant concealment to such vessels, but do not prevent line of sight.

The following table determines the amount of damage per round done to any vessel caught within an asteroid field or meteor shower.

Table: Random Hazards
d% Hazard Type
01-64 Open space (nothing)
65 Antimagic Field
66-69 Asteroid Field
70 Comet
71-74 Dust Cloud
75-77 Ice Field
78-79 Magnetic Field/Storm
80-82 Meteor Shower
83-85 Nebula
86-88 Radiation Belt
89 Ribbon Storm
90-92 Slipstream
93-95 Solar Flare/Wind
96-97 Wormhole
98-99 Roll Twice (ignore this result if rolled again)
100 Roll Three Times (ignore this result if rolled again)
Table: Cloud/Field Magnitudes
Magnitude1 Encounter Chance (%) Diameter (in Cubes) Size Modifier
Tiny 01-44 1 -2
Small 45-64 8 -1
Medium 65-74 27 +0
Large 75-84 64 +1
Huge 85-92 125 +2
Gargantuan 93-99 216 +4
Colossal 100 343 +8

1: Clouds and Fields in space do not have equivalent magnitudes for diminutive or fine.


Comets are colossal chunks of frozen gases, liquids, and rock that are hurtling through the void at incredible velocity. They throw off a long tail of melting gas and rock particles that can be seen stretching out behind it for tens of miles. While the odds of striking or being struck by a comet are incredibly remote, comets are usually harbingers of other dangers than just ice and rock. Strange creatures often accompany, or follow behind comets, and pirates or invasion forces often follow the trail of comets as they streak through the universe, for many cultures see comets as messengers of the void gods and blindly follow them through the void.

The tail of the average comet is only a single hex across and eight hexes long, though some comets are so large that their tails are up to eight hexes across and 50 hexes long. If a vessel flies through the tail of a comet, the damage is equivalent to that of an active asteroid field.

Comets often carry a wealth of valuable resources trapped within, and therefore, some adventurers and merchant guilds attempt to capture comets, or even mine them as they travel. Such work is incredibly dangerous, and many who attempt these acts do not survive, but the rewards are well worth the risks; most comets carry enough valuable ores and minerals to purchase a large city.

Dust Cloud

Cosmic dust is generally harmless, but it does obscure vision, as it reflects visible light, and if a vessel passes through it, it is coated in the dust particles until it is fully scrubbed clean; a process that can take days, depending upon the size of the vessel. While coated in cosmic dust, cloaked vessels no longer have an additional +8 AC bonus but they keep their immunity to TL. It may be a minor hazard, but it can be tactically effective.

Dust clouds that occupy hexes of space between, or surrounding, vessels in combat grant concealment to such vessels, but do not prevent line of sight.

EMP Field

There are zones, or bubbles, of electromagnetic radiation that float out in the depths of the void, trapping unsuspecting vessels that rely upon technology for their propulsion and preventing the usage of any and all technological items. While some are marked on star charts, others are either stumbled upon randomly, or can be marked by the presence of derelict vessels floating nearby. Scavengers and pirates are often wary of such “vessel graveyards”, as they may indicate the presence of nearby EMP fields.

EMP fields generally come in spherical form, and in order to escape from an EMP field, one can either hope to drift out of it, or by using some magical means of escape. There is no way of predicting how large an EMP field may be until it is fully explored. EMP fields do not have a tendency to drift or move in space, though certain astronomical events can shift their position.

Vessels that enter an EMP field under technological propulsion immediately stop accelerating and become incapable of changing direction. Trapped vehicles begin to decelerate due to microgravity within the EMP field at a rate of 1 Speed per round (minimum of 1 Speed), whereupon they drift in a random direction each round upon achieving Speed 1. Unwary travelers that do not have magical means of escape can remain stuck in EMP fields for so long that they either die of asphyxiation, dehydration, or starvation, depending on their reserves.

Table: Asteroid Fields &Amp; Meteor Showers
Asteroid Field (Passive) d% Asteroid Field (Active) d% Meteor shower d% Asteroid/Meteor Size Collision Damage (in VP) Profession (pilot) DC to avoid1
01-20 01-10 01-05 None
21-40 11-25 06-15 Diminutive 1d4 35
41-45 26-40 16-32 Tiny 1d6 32
46-59 41-55 33-52 Small 1d8 30
60-74 56-70 53-72 Medium 2d6 27
75-84 71-80 73-87 Large 3d6 25
85-91 81-90 88-95 Huge 4d6 22
92-97 91-95 96-98 Gargantuan 6d6 20
98-100 96-100 99-100 Colossal 8d6 15

1: Avoiding asteroids in an active asteroid field is far more difficult than avoiding asteroids in a passive field. Active asteroid fields add a cumulative +2 to the DC to avoid asteroids in consecutive rounds.

Ice Field

Ice fields can be just as deadly as meteor showers or asteroid fields, and can be just as harmful. As asteroid fields do, ice fields come in active and passive formats, and cause the same degree of damage, though half of that damage is bludgeoning damage and the other half results directly from the extreme cold of the ice.

Vessels sometimes play cat and mouse games within ice fields, despite the dangers. When vessels engage in combat within an ice field, all vessels only have a 25% chance of being hit by an attack each time they are targeted.

Ice fields that occupy hexes of space between, or surrounding, vessels in combat grant cover to such vessels, but do not prevent line of sight.

Magnetic Field/storm

Magnetic fields are stationary zones of incredibly powerful magnetic energies, while magnetic storms are similar zones that are mobile. Either type can cause major disruptions to purely technological systems and are best avoided if at all possible. When vessels pass through a magnetic field or storm, technological systems and objects take 5d6 HP of damage for each round that they are exposed to the effect. Objects made of iron or steel automatically adhere to the largest of such objects (which can include walls, floors or ceilings) and require a DC (15 + the magnetic field’s size modifier) Strength check to pry apart.

Vessels made of iron or steel are drawn together at the rate of 1 hexes per round, and multiple vessels can become magnetized together, effectively occupying the same square until they pass through the effect. Vessels that collide as a result of being magnetized together take 6d6 HP of damage for each vessel they collide with. Separating magnetized vessels requires a DC (20 + the magnetic field’s size modifier) Piloting check, provided that there is open space to move the vessel away.


Nebulae are largely stationary clouds of ionized, anti-magical gases that not only obscure vision, but can cause a multitude of vessel systems to temporarily malfunction. Defensive components (other than armor plating) and tactical systems fail to function within a nebula, as do teleportation devices and spells. Vision is obscured beyond a single hex, and Speeds are capped to a Speed 5. As nebulae can greatly interfere with a vessel’s ability to defend itself from attack, only the most damaged and desperate of vessels deliberately fly into a nebula in combat situations.

Nebulae that occupy hexes of space between, or surrounding, vessels in combat grant concealment to such vessels. However, vessels within a nebula do not have line of sight to vessels outside of the nebula, and vice versa, nor do vessels that have a nebula positioned between them.

Oort Cloud

Oort clouds exist in the vast pockets of void in interstellar space, and are impossible to avoid. They are comprised of frozen packets of water, ammonia and methane gases; are the spawning grounds of comets; and exert vast gravitational pressures upon the void in similar fashion to ocean tides.

For each 5 hexes that a vessel travels through an Oort cloud, they suffer a cumulative 5% chance of being “blown off course”, effectively doubling the number of hexes of the vessel must travel to get through the Oort cloud. Vessels using a phase box as their active engine are immune to this tidal effect.

Within an Oort cloud, all damage from cold-based environmental hazards such as comets or ice fields is doubled, as is any radiation damage regardless of its source. However, due to the incredibly high concentration of ammonia in an Oort cloud, acid damage from environmental hazards or attacks upon a spacefaring vessel is halved.

Lastly, it is incredibly dangerous to work on the outer hull of a vessel within an Oort cloud. Creatures on the outside of a vessel’s hull must make a DC 30 Athletics check as a swift action each round or be swept off of the vessel and carried out into the void.

Oort clouds that occupy hexes of space between, or surrounding, vessels in combat grant improved cover to such vessels. However, vessels within an Oort cloud do not have line of sight to vessels outside of the Oort cloud, and vice versa, nor do vessels that have an Oort cloud positioned between them.

Planetary Ring

While not every planet has them, planetary rings are very similar to asteroid belts. They are typically passive in nature, and some are made entirely out of ice, dust, or gases instead of rocks. In fact, most planets that possess ring systems have rings that are made out of a combination of materials.

Planetary rings form in a variety of ways; often either by the debris of moons that were impacted by some large object, the debris of moons that were ripped apart by their planet’s gravitational forces, or potentially even the collection of dust clouds that drifted too close to a planet’s orbit.

Table: Planetary Rings
Size Classification Width (in hexes) Depth (in hexes)
Vermin 1-4 1
Familiar 5-11 2
Stirge 12-20 3
Fey 21-31 4
Humanoid 32-45 5
Chimera 46-62 6
Hydra 63-81 7
Kraken 82-103 9
Dragon 104+ 10

Regardless of the reason for the formation of a planetary ring, they are treated as if they had the qualities of all of the environmental hazards that are similar in their makeup: if rocks are present, treat them as a passive asteroid field. If they contain ice, treat them as if they were an ice field. If dust is part of their makeup, treat them as if they were a dust cloud. If they are made up, even in part, by gases, treat them as if they were a nebula.

Planetary rings can grow to nearly any size. See a planet’s size classification to determine the size of the planetary ring.

Radiation Belt

Radiation belts are swaths of radiation floating out in the void. Vessels that pass through radiation belts are unharmed, but their crews suffer the effects of radiation for as long as they remain within the irradiated areas.

Ribbon Storm

Ribbon storms are one of the deadliest and most insidious hazards of space travel. A ribbon storm is comprised of foot-long hyper-virulent fungal filaments capable of eating through most anything they come into contact with using hyper-corrosive acids. As each fungal filament, or ribbon, feeds, it grows in size, reaching lengths of ten feet and swelling to a foot in diameter. Full grown ribbons die within minutes. These ribbons only devour what they come into contact with; on their own, they do not move or attack nearby beings. They have no muscular system, being comprised of tightly wound strands of fiber, nor do they have anything resembling a nervous system. They merely excrete powerful acids and the outer surface absorbs the resulting slurry.

Ribbon storms are high-density fields of floating ribbons that travel through space, often in the wake of a comet, asteroid, or vessel. When ribbon storms are encountered in deep space, they are often left there as a result of falling too far behind whatever was dragging them along.

Occasionally, ribbon storms are brought into contact with a planetary body, and although most ribbons burn up in the atmosphere, more than enough survive to make landfall, eagerly devouring all matter they come into contact with.

No one quite knows where ribbons come from, but it is known that they reproduce asexually, breaking off into smaller segments which grow into filaments that are ready to feed.

Traveling through a ribbon cloud causes 1d6 HP of damage per round to any vessels caught within the storm. Ribbons that touch living creatures or constructs that are not immune to their acids inflict 10d6 damage per round that they remain in contact.

A ribbon is particularly vulnerable to fire, burning up completely on contact. It also drowns in water within 1 round, its acids dissipating harmlessly.

Ribbon storms that occupy hexes of space between, or surrounding, vessels in combat grant soft cover to such vessels, but do not prevent line of sight.


Slipstreams are invisible rivers of force that drag vessels along in their wake. While they are largely undetectable, there are quite a few slipstreams that are marked on star charts. They rarely travel through a solar system, but they often travel near enough to them that they are regularly used as “space lanes” for traders, adventurers, and pirates.

Slipstreams can be dangerous to cross; traveling across a slipstream exerts extreme gravitational forces upon the vessels that cross them. However, traveling along with the slipstream is expeditious. Vessels plot their course along the slipstream’s path and merge together with it seamlessly (taking no damage).

A slipstream’s force is determined by its size; lesser, standard, or greater. Consult the chart below to determine a slipstream’s Speed and force.3

Solar Flare/wind

Solar phenomenon only occur within solar systems, but their effects can be quite powerful. Solar flares can lash out from any type of star to a distance of thousands of miles, while solar winds are charged particles that are flung outward from stars. Each can have devastating effects upon vessels that pass through them.

Solar winds can knock vessels off course. Unless the vessel is propelled by magic, passing through a solar wind pushes a vessel 1d6+1 hexes per round in the direction that the solar wind is traveling. Some vessels use solar winds to help propel them faster, riding the solar wind toward the outermost planets of the system.

Solar flares are another matter entirely. Vessels caught within the blast of a solar flare can take a punishing amount of fire and heat damage, and many do not survive. Even the heaviest of spacefaring vessels take critical damage from being caught within a solar flare, unless they are protected from fire damage.

Solar winds use the same size chart for cloud or field hazards to determine their size. Solar flares use this chart below to determine their size and how much damage they do.


Wormholes are random portals that transport vessels that travel through them to other parts of galaxies, or even to other galaxies altogether. There is no predicting where a wormhole will take you to except by exploring it, but there is some prediction as to where wormholes may occur.

Wormholes are unstable, and any vessel passing through it risks taking damage, or even the wormhole’s collapse. Any vessel passing through a wormhole takes 6d6 HP of damage. If the vessel’s pilot succeeds at a DC 25 Piloting check, the vessel only takes half damage. Should the pilot roll a natural 1, the wormhole collapses, inflicting 12d6 HP of damage to the vessel. Vessels destroyed in this matter are completely lost within the wormhole, as are their crews.

Once a wormhole collapses, it no longer exists.

Table: Slipstreams
Slipstream Type Slipstream Diameter Force Damage per round (in VP)1 Speed Boost
Lesser 4 Cubes 4d8 +3 Speed
Standard 8 Cubes 6d8 +5 Speed
Greater 16 Cubes 8d8 +10 Speed

1: Force damage is only inflicted if a vessel is crossing or traveling against the flow of the slipstream.

Solar Flares
Star Type Flare Size (x10 Cubes) Flare Diameter (in Cubes) Flare Damage (in VP)
Blue Star 6d12+9 17 4d20+50
Blue-White Star 4d8+7 15 2d20+40
Brown Dwarf
Orange Star 2d4+1 8 2d8+20
Red Star 1d6+1 8 2d6+10
Red Supergiant 1d6+1 8 2d6+15
White Dwarf 2d8+5 13 3d8+30
White-Blue Star 2d8+5 13 2d20+30
Yellow Star 2d4+3 10 2d4+25
Section 15: Copyright Notice

Starjammer – Starfinder Compatible Version © 2017 Open Gaming LLC; Authors: Peter K. Ullmann, Kirby Flake, John Starjammer – Starfinder Compatible Edition © 2017 d20pfsrd.com Publishing; Authors: Peter K. Ullmann, Kirby Flake, John Reyst, Troy Daniels, Michael McNeill, Manuel A. Oaxaca, Allen Snyder, Michael Ritter; Conversion to Starfinder by Tyler Beck, Kim Frandsen, Michael Ritter, Peter K. Ullmann.