Enviornment

In any given campaign your adventure still needs a location in which to take place in. This section will give you all the necessary rules, conditions, and factors you will need to give form to the various places and locations in your campaign. In earlier role playing games locations mostly existed as static backdrops to adventures but not in D20 Sci-Fi. Pain staking steps have been taken to ensure that a GM can really immerse players in a rich world of their own creation with much less effort than it once took to do so.

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Star Systems

Stellar & Space Hazards

Wilderness

Aquatic Terrain

Desert Terrain

Forest Terrain

Marsh Terrain

Mortuary Terrain

Mountain Terrain

Plains Terrain

## **Gravity**

The force that gravity exerts on a person determines how they develop physically as well as their ability to preform certain actions. In addition, gravity affects the amount of damage a character takes from falling. Gravity conditions may vary considerably from one environment to the next. However, for ease of Play D20 Sci-Fi four simplified gravity environments: normal gravity, low gravity, high gravity, and zero gravity.

### **Normal Gravity**

“Normal gravity” equates to the gravity here on Earth. Environments with normal gravity impose no special modifiers on any actions that anything can make, in D20 Sci-Fi. Likewise normal gravity does not modify a creature's speed, carrying capacity, or the amount of damage a character takes from a fall.

### **Low-Gravity Environments**

In a low-gravity environment, the pull of gravity is significantly less than what we experience living on Earth. Although an object's mass doesn't change, it becomes effectively lighter. This means that bounce when they walk. It becomes easier to move and lift heavy objects as well as preform strength related tasks. In addition, creatures take less damage from falling.

**Speed:** A creatures speed increases by +1 meter in a low-gravity environment. This bonus applies to all of the creature's modes of movement.

**Carrying Capacity:** A creature's normal carrying capacity is doubled in a low-gravity environment. In addition, the creature gains a +10 bonus on any strength check made to lift or move a heavy unsecured object.

**Skill Check Bonuses:** Creatures in a law-gravity environment gain a +10 bonus on strength-based skill checks.

**Attack Roll Penalty:** Creatures take a -2 penalty on attack rolls in a low-gravity environment unless they are native to that environment or have the Zero-G Training feat.

**Damage from Falling:** Creatures do not fall as quickly in a low-gravity environment. Falling damage is reduced from 1d6 points per 3 meters to 1d4 per 3 meters fallen.

**Long-Term Effects:** Long-term exposure to low-gravity conditions can cause serious problems when returning to normal gravity. A creature that spends 120 hours or more in a low-gravity environment takes 1d6 points of temporary Strength damage upon returning to normal gravity.

### **High-Gravity Environments**

In a high-gravity environments. The pull of gravity is significantly greater than that witch we experience living here on Earth. Although an object's mass doesn't change, it becomes effectively heavier. It becomes harder to move and carry heavy objects as well as perform Strength-related tasks. In addition, creatures take more damage from falling. Even the simple task of walking or lifting one's arms feels more laborious.

**Speed:** a creature's speed decreases by -1 meter to a minimum of 0 meters in a high gravity environment. This penalty applies to all of the creature's modes of movement.

**Carrying Capacity:** A creature's normal carrying capacity is halved in a high-gravity environment. In addition, the creature takes a -10 penalty on any Strength check made to lift or move a heavy unsecured object.

**Skill Check Bonuses:** Creatures in a high-gravity environment take a -10 penalty on Strength-based skill checks.

**Attack Roll Penalty:** Creatures take a -2 penalty on attack rolls in a high-gravity environment unless they are native to that environment.

**Damage from Falling:** creatures fall quickly in a high-gravity environment than they do in normal- or low-gravity environments. Falling damage is increased from 1d6 points per 3 meters fallen to 1d8 points per 3 meters fallen.

**Long-Term Effects:** Long-term exposure to high-gravity conditions can cause serious problems when returning to normal gravity. A creature that spends 120 hours or more in a heavy-gravity environment takes 1d6 points of temporary Dexterity damage upon returning to normal gravity.

### **Zero-Gravity Environments**

Creatures in zero-gravity environment can move enormously heavy objects. As movement in zero gravity requires only the ability to grab onto or push away from larger objects, Climb and Jump checks no longer apply. Most creatures find zero-gravity environments disorienting, taking penalties on their attack rolls and suffering the effects of Space Adaptation Syndrome (space sickness). In addition, creatures in zero gravity are easier to bull rush than in other gravity environments.

**Space Adaptation Syndrome:** A creature exposed to weightlessness must make a Fortitude save (TN 15) to avoid the effects of space sickness. Those who fail the save are shaken, and those who fail the save by 5 or more are nauseated. The effects persist for 8 hours. A new save is required every 8 hours the creature remains in a zero-g environment. Creatures with the Zero-G Training feat do not suffer the effects of space sickness (robots and droids are also immune to space sickness).

**Speed:** While in a zero-g environment, a creature gains a fly speed equal to its base land speed, or it retains its natural fly speed (whichever is greater). However, movement is limited to straight lines only; a creature can change course only by pushing away from larger objects (such as bulkheads).

**Carrying Capacity:** A creature's normal carrying capacity increases by 10 times in a zero-gravity environment. In addition, the creature gains a +20 bonus on any Strength check made to lift or move a heavy unsecured objects.

**Attack Roll Penalty:** Creatures take a -4 penalty on attack rolls in a zero-gravity environment unless they are native to that environment or have the Zero-G Training feat.

**Modified Bull Rush Rules:** A creature affected by a bull rush is pushed back 3 meters, plus 3 meters for every 5 points by which its opponent's Strength check result exceeds its own.

**Long-Term Effects:** Long-term exposure to zero-gravity conditions can cause serious problems when returning to normal gravity. A creature that spends 120 hours or more in a zero-g environment takes 2d6 points of temporary Strength damage upon returning to normal gravity.

### **Weight Vs. Mass**

While an object in zero gravity loses weight, it does not lose mass or momentum. Thus, while a character could push a 10-ton piece of equipment around in space, albeit slowly, getting it to stop is a bit difficult. If a character were to come between that piece of equipment and a solid object, that character would be crushed as if he were in full gravity – just more slowly. For simplicity, assume that a Strength check to lift or move an object in zero gravity gains a +20 circumstance bonus. However, stopping an object already in motion does not receive this same bonus.

## **Atmospheric Conditions**

As with variants in gravity, a change in atmospheric conditions can cause problems for characters. Unfortunately, not every planet will have the same atmospheric density or chemical composition as Earth, meaning that worlds otherwise habitable to human life may not be ideal for humans born and raised on Earth.

### **Corrosive Atmosphere**

Some atmospheres (breathable or not) contain chemicals and gases. Corrosive atmospheres slowly eat away at foreign equipment and can cause significant equipment failure. The corrosion can be particularly troublesome in atmospheres that demand special survival gear, as any breach in a protective environmental suit renders it useless. Unprotected equipment and vehicles (shields do not protect against atmospheric conditions) exposed to a corrosive atmosphere takes 1d4 points of acid damage per hour of exposure. This damage ignores hardness and deals damage directly to the equipment, eating away at it slowly. Creatures not wearing protective gear in a corrosive atmosphere takes 1d4 points of acid damage per round of exposure.

### **Thin Atmosphere**

Planets with thin atmospheres have less oxygen per breath than the standard Earth atmosphere. When dealing with thin atmosphere conditions, the character must make a Fortitude save to see if he or she suffers any ill effects. Being under such conditions can be disorienting and can cause a character to become sluggish, slowly whittling the character down as the brain is deprived of normal levels of oxygen. See the Table: Atmospheric Conditions for any ability modifiers and special conditions caused by thin air.

### **Thick Atmosphere**

Thick atmospheres are those that contain a more dense concentration of certain elements, like nitrogen, oxygen, or even carbon dioxide, than the standard Earth atmosphere. These dense atmospheres sometimes contain a different balance of elements, while others simply contain a higher number of gases in each breath. Regardless of the form, a thick atmosphere can be just as dangerous as a thin atmosphere over a long period of time. Though atmospheres that are slightly thicker than normal atmospheres do not have as significant an effect as slightly thinner atmospheres, remaining in a thicker atmosphere causes the same drain on the body.

### **Toxic Atmosphere**

Some atmospheres (breathable or not) contain toxic gases that are debilitating or lethal to some or all forms of life. A GM who wishes a particular planet or environment to have a toxic atmosphere should select an inhaled poison from Chapter 6: Equipment. Treat the atmosphere as always containing that poison.

### **Vacuum**

Despite some popular myths, moving into a vacuum dose not cause the body to explosively decompress, nor dose it cause instant freezing as heat bleeds away from the body. Rather the primary hazards of surviving in the vacuum of space are the lack of air and exposure to unfiltered ionizing radiation.
On the third round of exposure to vacuum, a creature must succeed on a Constitution check (TN 20) each round or suffer from aeroembolism (“the bends”). A creature that fails the save experiences excruciating pain as small air bubbles form in its bloodstream; such a character is considered stunned and remains so until returned to normal atmospheric pressure. A creature that fails the Constitution check by 5 or more falls unconscious. The real danger of vacuum comes from suffocation, though holding one's breath in vacuum damages the lungs. A character who attempts to hold his breath must make a Constitution check (TN 15) every round; the TN increases by 1 each round, and on a successful check the character takes 1 point of Constitution damage (from the pressure on the lining of his lungs). If the check fails, or when the character simply stops holding his breath, he begins to suffocate. See Suffocation section earlier in this chapter.

### **Decompression**

The sudden decompression of a space vehicle can be dangerous to creatures inside. Whenever a sealed environment within a vacuum is breached, all of the air inside rushes out quickly to equalize the air pressure. Creatures within the decompressing environment must succeed a Reflex save (TN 15) or be thrust toward the breach (and possibly beyond it) at a speed of 20 meters per round. Creatures that are three size categories larger than the breach's size category are big enough not to get dragged toward the breach (no Reflex save required). For example, a Fine breach pulls only Fine, Diminutive, and Tiny creatures toward it; creatures of Small size or larger are unaffected. If the breach's size category is larger than the creature's size category, the creature passes through the opening and is blown out into vacuum and takes 1d6 of damage as it gets pushed through the breach. If the breach's size category is the same as the creature's size category, the creature is blown out into vacuum and takes 1d6 points of damage as it gets pushed through the breach. If the breach is one or two size categories smaller than the creature's size category, the creature isn't thrust into vacuum but takes 2d6 points of damage as it slams against the area around the breach. It takes another 2d6 points of damage each round until the air completely evacuates from the decompressed compartment or until the creature pulls itself away from the breach with a strength check (TN 20). The time it takes for all of the air to evacuate from a compartment depends on the size of the breach and the volume of the decompressing compartment, as shown in the Table: Decompression Times. Once the air has completely rushed out through the breach, the pressure equalizes and the interior environment becomes a vacuum.

## **Battle Terrain**

The primary terrain of a battlefield has a dramatic effect on the encounters that take place on it. Various terrain features can help or hinder troops, providing significant advantages to those who know how to exploit them.

### **Forest Battlefields**

Conﬂicts in forested terrain are more likely to be isolated skirmishes rather than massive armies lined up for battle. Undergrowth hampers movement, and thick trees make it difficult to maintain orderly formations. Line of sight is limited, which hinders a commander’s ability to direct (or rally) troops. The foliage provides plenty of opportunities for a defending force to lay traps and ambushes, hiding camouflaged. The trees provide cover, so ranged attacks and artillery have significantly reduced effectiveness. The abundance of available wood in a forest lends itself to the creation of fortiﬁcations. Many other manufactured features might litter a potential battlefield site in such a sylvan setting, including pit traps, covered stakes, or wooden palisades. The defending force usually has an advantage, supplementing the natural obstacles of the forest with structures placed to funnel troops through choke points or into lines of ﬁre. A garrisoned troop might clear away sections of the forest nearest the walls of their building to provide a better view of approaching attackers.

### **Marsh Battlefields**

The mud and muck of marsh terrain slows armies considerably, and the dangers inherent in traversing such terrain encourage commanders to avoid marshlands. When battles do occur in such terrain, they can be even more dangerous, since an injury that would otherwise cause unconsciousness proves deadly when the soldier disappears beneath a bog and quickly drowns. Fortiﬁcations in marshes are uncommon, because ﬁnding a foundation is difficult. On occasion, ruins of former structures that were built before the ground became too waterlogged can provide solid footing. Murky water or loose topsoil offers many opportunities to lay triplines, spikes, or other such traps; creatures that swim or don’t require air might also hide in the depths.

### **Hill Battlefields**

Many battles occur around hilltops, since these are usually the most advantageous positions to build a fortress or a keep that can maintain a vantage point. Armies assault or lay siege to these key objectives as a matter of course. Sometimes a great battle might be waged in a shallow valley between two hillocks, where the commanders can both look down upon the melee as it unfolds. Rugged hills offer plenty of hiding places, even for entire regiments, so skirmishes or small battles could result from ambushes. A battlefield in the hills could have any number of fortiﬁcations, earthworks, or other terrain features, created by either the attackers or the defenders. Higher ground offers a significant advantage for an army, doubly so if it also occupies a stronghold atop a hill. Ruins of previous structures might provide low walls for cover. Natural features such as undergrowth, streams, and the occasional tree are also scattered about most hills terrain.

### **Mountain Battlefields**

Massive conﬂicts in mountain terrain usually occur in alpine meadows. Only in such places is there enough open space for armies to gather into any sort of formation. Cliffs, chasms, and rubble make it difficult. to muster a force of significant size in rugged mountains, and most great battles in (and over) forbidding mountains are usually of the aerial variety.

### **Desert Battlefields**

The shifting dunes of a sandy desert quickly overcome any attempt at fortification. Trenches ﬁll in with sand, walls become buried under sand dunes, and earthworks simply blow away. Rocky deserts and tundra both hamper the creation of structures due to a lack of available material. Desert battlefields most often have just natural terrain features and few, if any, manufactured ones.

### **Plains Battlefields**

Large meadows or tracts of farmland are perfect stages for clashes between massive armies, making plains terrain the most common site of battlefield adventures. While some plains are devoid of natural structures, nearly any manufactured feature can exist on a plain. Fences and cottages are common in farmland regions, while defensive fortiﬁcations can be built anywhere war is expected.

### **Aquatic Battlefields**

On the surface of the sea, great ships might pound each other with artillery, attempting to gain supremacy over trade lanes or waterways. Battles underwater more closely resemble aerial combat than land melee: Troops attack from above or below, without much terrain in the way. In some cases, an underwater volcano, a kelp forest, or a sunken city might be the site of a battle. Most of the features and fortiﬁcations described in the following sections do not have an underwater analogue. Visibility is, however, a greater concern underwater, since the blood that escapes from wounded combatants clouds the water like smoke (as well as attracting unwanted complications, such as swarms of sharks).

### **Underground Battlefields**

Large-scale battles in subterranean areas take place in massive caverns or great tunnel complexes. The presence of a natural ceiling usually precludes the use of high-arcing artillery, and the environmental features lend themselves to defense and the creation of defensive fortiﬁcations. Most structures are manufactured from stone, given the dearth of available lumber in the depths of the world. Light, or the lack of it, is a factor for most races; even drow can only see out to 120 feet in complete darkness, far shorter than line of sight on the surface world.

### **Urban Battlefields**

When the outer defenses fall, the battle might move into a city’s streets. Buildings, back alleys, and sewers provide many ways for a defending force to move about unseen or for an invading army to infiltrate. Narrow thoroughfares reduce an army’s ability to outflank opponents, and most ﬁghting is reduced to skirmishes between units or house-to-house battles. While earthworks might only exist in park-like areas or within the grounds of a manor, barricades and other debris might litter an urban battlefield. The buildings themselves provide a unique terrain feature, and offer cover for archers or other harrying forces.

## **Space Rules and Enviornments**

### **Star Systems**

A star system can contain one star or multiple stars. Humans are more likely to find habitable planets in systems with a single star. In reality, more than half of all star systems have two or more stars, and these systems typically contain planets that are inhospitable to human life. Granted, any D20 Sci-Fi game can feature a hospitable planet orbiting a binary or trinary star system, and indeed it does make a more interesting vista, but the reality is that such systems usually produce planets that are too hot, cold or irradiated to support human life. This quick guide can give you a better idea of what kind of star system you may want to use in your campaign.

### **Stellar & Space Hazards**

Two types of stellar hazards can create higher-than-normal levels of ionizing radiation: solar flares and cosmic rays. Space travel is nowhere near as easy as books and movies make it seem. Foreign objects are a constant danger; even a micro-meteoroid traveling at a high enough velocity can punch a hole through a starship's hull and expose the entire crew to the vacuum of space. Here is a more comprehensive list of the dangers that potential space-borne travellers may encounter.

## **Traveller Science**

### **Realistic Travel Times**

Table: Realistic Travel Times provides various “realistic” interplanetary and interstellar travel times. These times assume that starships cannot achieve velocities anywhere near the speed of light, for reasons discussed under Interstellar Travel (see below). Using the table, a starship equipped with a PL 6 ion engine would take 67.2 days to travel from Earth to Mars, while the same ship equipped with a PL 7 induction engine would take 16.8 days. The travel times listed are based on average distance. Planets move closer together and farther apart based on their relative orbits around the sun, and the travel time between worlds may increase or decrease accordingly.

### **Realistic Space Travel**

When speaking of space travel, it is important to distinguish interplanetary travel from interstellar travel. Travel between planets is within the grasp of modern technology and is likely to become easier as science develops new fuel sources or new ways to maximize existing fuel sources. Travel between stars, on the other hand, calls for some truly radical leaps in a number of different fields.

### **Interplanetary Travel**

In Progress Level 5, humanity has the technology to send unmanned probes to the edge of the solar system. However, human sojourns into space are limited to orbital missions and trips to the Moon, as longer journeys would take decades and consume ridiculous amounts of fuel and oxygen. Interplanetary travel becomes possible at Progress Level 6. Ships fitted with magnetic ram scoops allow the crew to manufacture fuel from particles of hydrogen gas floating loose in space (though at only a few atoms per cubic inch). Such a ship could even incorporate a particle accelerator that converts matter into antimatter—with far more efficient thrust-to-payload ratios than solid fuel. With a sufficient supply of food, water, and oxygen, a ship so equipped could travel to the edges of the solar system and perhaps to another solar system entirely.

### **Interstellar Travel**

Realistically, the starships presented in the Starships section are capable only of interplanetary travel, not interstellar travel. The reason for this is simple: Even the best engine can’t accelerate a ship to light speed, and without light speed, interstellar journeys take tens of thousands of years. The speed of light is 186,000 miles per second. That’s 1,116,000 miles per round, or 66,960,000 miles per hour. Maneuvering a ship at this speed is a tricky proposition; by the time you notice an object in your path, it’s probably too late to avoid it. One must also consider relativity: The closer the ship’s velocity comes to the speed of light, the greater its mass. A starship cannot achieve light speed via simple acceleration, no matter how powerful the ship’s engine, as increasing the power only increases the mass. The greatest impediment to traveling between the stars is time: What would be the point of sending astronauts to Alpha Centauri, for example, if, by the time they arrived, no one on Earth could remember why they’d gone in the first place? Time dilation—the slowing of the passage of time in relation to an object traveling at close to the speed of light—becomes a factor. A few years might pass on board the ship, while a few hundred years might have passed both at the ship’s point of origin and its point of arrival.

### **Time Dilation**

When a ship approaches to within 90% of the speed of light, time slows down. Characters on board the ship would not notice, but if they were to make hourly reports back to their point of origin, those reports might arrive only once every hundred hours. This creates an interesting paradox, in that if a character managed to travel at the speed of light to another star and back again, a newborn child he left behind would now be older than him—if the child hadn’t died of old age some time ago. The actual amount of time dilation observed aboard a ship traveling near light speed increases in proportion to just how close it is to light speed. Technically, time dilation occurs at any speed, but it only becomes noticeable at relativistic speeds. The dilation is a ratio that determines how much time passes aboard the ship; it is a multiplier when determining how much time passes outside the ship. For example, a ship moving at 70% the speed of light has a time dilation of 1.4. Ten hours of travel aboard the ship at this speed means that 14 hours (10 × 1.4) have passed outside the ship. However, if ten hours pass for those left behind, only 7.1 hours have passed aboard the ship (10 divided by 1.4).

**Starship Speed:** The vessel’s speed in miles per second.

**AU per Hour:** How many Astronomical Units (AU) a vessel traveling at this speed can cross in 1 hour. One AU equals 93,000,000 miles (the distance between the Sun and the Earth).

**% Speed of Light:** The percentage of the speed of light (186,000 miles per second).

**Time Dilation:** Divide the time traveled by this number to arrive at the amount of time that passes on board the starship.

## Wilderness and Terrain Types

### **Wilderness**

Outside the safety of city walls, the wilderness is a dangerous place, and many adventurers have gotten lost in its trackless wilds or fallen victim to deadly weather.

### **Aquatic Terrain**

Aquatic terrain is the least hospitable to most PCs, because they can’t breathe there. Aquatic terrain doesn’t offer the variety that land terrain does. The ocean floor holds many marvels, including undersea analogues of any of the terrain elements described earlier in this section. But if characters find themselves in the water because they were bull rushed off the deck of a pirate ship, the tall kelp beds hundreds of feet below them don’t matter. Accordingly, these rules simply divide aquatic terrain into two categories: flowing water (such as streams and rivers) and non-flowing water (such as lakes and oceans).

### **Desert Terrain**

Desert terrain exists in warm, temperate, and cold climates, but all deserts share one common trait: little rain. The three categories of desert terrain are tundra (cold deserts), rocky desert (often temperate), and sandy desert (often warm). Tundra differs from the other desert categories in two important ways. Because snow and ice cover much of the landscape, it’s easy to find water. And during the height of summer, the permafrost thaws to a depth of a foot or so, turning the landscape into a vast field of mud. The muddy tundra affects movement and skill use as the shallow bogs described in marsh terrain, although there’s little standing water.

### **Forest Terrain**

Forest terrain can be divided into three categories: sparse, medium, and dense. An immense forest could have all three categories within its borders, with more sparse terrain at the outer edge of the forest and dense forest at its heart.

### **Marsh Terrain**

Two categories of marsh exist: relatively dry moors and watery swamps. Both are often bordered by lakes (described in Aquatic Terrain), which are effectively a third category of terrain found in marshes.

### **Mortuary Terrain**

Two categories of terrain exist here: graveyards, open fields spotted with headstones and graves, and catacombs, underground spaces usually reserved for smaller boxes, typically the remains of cremation ceremonies.

### **Mountain Terrain**

The three mountain terrain categories are alpine meadows, rugged mountains, and forbidding mountains. As characters ascend into a mountainous area, they’re likely to face each terrain category in turn, beginning with alpine meadows, extending through rugged mountains, and reaching forbidding mountains near the summit.

### **Plains Terrain**

Plains come in three categories: farms, grasslands, and battlefields. Farms are common in settled areas, while grasslands represent untamed plains. The battlefields where large armies clash are temporary places, usually reclaimed by natural vegetation or the farmer’s plow. Battlefields represent a third terrain category because adventurers tend to spend a lot of time there, not because they’re particularly prevalent.