Gravity

The force that gravity exerts on a person determines how they develop physically as well as their ability to perform 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. For ease of play these rules present four simplified gravity environments: normal gravity (1.0 g), low gravity (<1.0 g), high gravity (>1.0 g), and zero gravity (0 g). The following sections summarize the game effects for each type of environment.

Normal Gravity

“Normal gravity” equates to gravity on Earth. Environments with normal gravity impose no special modifiers on a character’s ability scores, attack rolls, or skill checks. Likewise, normal gravity does not modify a creature’s speed, carrying capacity, or the amount of damage it 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 creatures bounce when they walk. It becomes easier to move and lift heavy objects as well as perform Strength-related tasks. In addition, creatures take less damage from falling.

Speed: A creature’s speed increases by +5 feet 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 low-gravity environment gain a +10 bonus on Strength-based skill checks (including Climb, Jump, and Swim 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 as they do in a normal- or high-gravity environment. Falling damage is reduced from 1d6 points per 10 feet fallen to 1d4 points per 10 feet 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 environment, the pull of gravity is significantly greater than that which we experience living 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 –5 feet (to a minimum of 0 feet) 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 (including Climb, Jump, and Swim 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 more quickly in a high-gravity environment than they do in a normal- or low-gravity environment. Falling damage is increased from 1d6 points per 10 feet fallen to 1d8 points per 10 feet 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 a 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 (DC 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 also 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.

Speed: While in a zero-gravity 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 object.

Attack Roll Penalty: Creatures take a –4 penalty on attack rolls and skill checks while operating 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 10 feet, plus 10 feet 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-gravity 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 more 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.