Gravity and Origin

If I am going to justify these suggestions, I need to assume a critical perspective.

The new Transport Union Edition of The Expanse RPG updated and streamlined rules gravity, making them more clear and less fiddly, in a neat table. However, if you look at the table, recall the books standard acceleration descriptions, you realise that Belters cannot run in ships accelerating more than 0.09 g. And if you look at the gravity of Ceres and Ganymede, you will see that these have 0.3 and .134 g respectively. Thus, even a Belter native to these places, cannot run or charge. Sure, handwavium is a thing. But I feel this is less elegant than what could have been done.

Below are some suggestions for change. One adds another level of lower gravity to fix the running issue mentioned above, the other adds native origins detached from cultural and factional background. I have also added native gravity descriptions, some with extra rules, but mostly just fluff. Feel free to use, change, adapt, and make these your own, to ensure that gravity “works” as you want in your games.

Gravity penalties

First, is the expansion of the table to add another row of gravity:

Table 1
Gravity Penalties
Gravity / Origin	Belters	Earthers	Martians
Microgravity (less than 0.1 g)	– (none)	-2	-1
Very low g (0.1 to 0.3 g	– (none)	-1	– (none)
Low g (0.31 to 0.8 g)	Fatigued	-1	– (none)
Standard g (1 g or slightly more or less)	Hindered	– (none)	Fatigued
Heavy g (2 to 3.9 g)	Restrained	Fatigued	Hindered
Very heavy g (4 to 8 g)	Restrained	Hindered	Restrained
Extreme g (more than 8 g)	Restrained (Dying)	Restrained	Restrained

I have added two rows to the table presented in the TUE rulebook. The key row is the “very low g” row. This enables Belters to move around in native gravities, including places like Ceres, Eros, Ganymede, and spin stations like Tycho, without suffering conditions that prevents them from running. The table maintains everything else, however, as you can see, Earthers are now more “at ease” in a narrower band of gravities compared to Belters and Martians. In principle, Martians could have a -1 in Very low g too, so feel free to change that, but I felt that these advantages for Martians and Belters are small compared to the risks they face in heavier gravities.

The second row added, “Extreme g” is perhaps less useful, but could be helpful in rare instances where characters are exposed to extreme gravity – it mainly affects Earthers, making them restrained – but this is also a circumstance wherein Belters are likely to not only be restrained, but potentially expire due to their own mass. In this last instance, the Dying condition can either be rounds until death, or minutes.

Note on Earther: it may be worth changing the penalty in Very low g to -2.

Native gravity and origin

The second expansion moves away from choosing faction and origin at the same time. The TUE rulebook missed out on an opportunity here, to separate culture and faction from native gravity. That is to say, instead of picking Belter or Earther, you pick native gravity. This makes sense for Belters from different kinds of habitats. Pallas may be microgravity only, whereas Ceres has low gravity, and Ganymede has very low gravity. Being native to a colony with higher or lower gravity is now also possible, and gives some choice and consequences to how to deal with gravity. This leaves the faction and culture choices out of determining native gravity, which at least by the end of book 4 and onwards becomes less of a thing for colonists. Some will hold on to earther, martian, or belter culture, regardless of being on a very low, low, standard, or high gravity colony – and from there it develops (and others will found colonies on alternative values and principles). Still, native gravity is a central crux to the Free Navy conflict, and the role of the TU.

In principle, you can just change the title of the columns in the TUE rulebook, replacing Belter with “microgravity”, Martian with “low gravity”, and Earther with “Earth gravity”. This means, you can choose a Belter from a low gravity habitat, every cultural part remains the same, focus and language and such, but you just look in the Martian column for gravity rules. A colonist with a Belter background may look in the Earther column, if that is the native gravity of the character.

However, if you like the added granularity of the previous table, I have a few different versions below here you can consider and take inspiration from, if nothing else.

The first is a re-labelled version of the table above (plus a heavy gravity column for relevant colonies if you consider that relevant for your game).

Table 2
Native Gravity and Penalties
Gravity / Origin	Microgravity	Low gravity	Standard gravity	Heavy gravity
Microgravity (less than 0.1 g)	– (none)	-1	-2	-3
Very low g (0.1 to 0.3 g)	– (none)	– (none)	-1	-2
Low g (0.31 to 0.8 g)	Fatigued	– (none)	-1	-2
Standard g (1 g or slightly more or less)	Hindered	Fatigued	– (none)	-1
Heavy g (2 to 4 g)	Restrained	Hindered	Fatigued	– (none)
Very heavy g (4 to 8 g)	Restrained	Restrained	Hindered	Fatigued
Extreme g (more than 8 g)	Dying	Restrained	Restrained	Hindered

Pick from one of four origins by native gravity columns, and add it under Origin on your character sheet. If you have chosen Microgravity, you will see that for certain situations, such as on a planet or during high acceleration of over 8g, the Dying condition can be applied, but GMs would be wise to consider changing the conditions from rounds until death to minutes until death.

Note on Earth gravity: it may be worth changing the penalty in Very low g to -2.

The next table is a bit “harsher,” taking inspiration from the TUE table, but adding another native gravity (very low gravity) for more nuance. It is “harsher” by giving all origins only one gravity without penalties. This is odd with the distinction between very low and low gravity, but that is still in line with the TUE logic – and could arguably make sense for some.

Table 3
Native Gravity and Penalties
Gravity/Origin	Microgravity	Very Low gravity	Low gravity	Standard gravity	Heavy gravity
Microgravity (less than 0.1 g)	– (none)	-1	-1	-2	-3
Very low g (0.1 to 0.3 g)	Fatigued	– (none)	-1	-1	-2
Low g (0.31 to 0.8 g)	Hindered	Fatigued	– (none)	-1	-2
Standard g (1 g or slightly more or less)	Restrained	Hindered	Fatigued	– (none)	-1
Heavy g (2 to 4 g)	Restrained	Restrained	Hindered	Fatigued	– (none)
Very heavy g (4 to 8 g)	Restrained (Dying)	Restrained	Restrained	Hindered	Fatigued/Hindered
Extreme g (more than 8g)	Dying	Restrained (Dying)	Restrained	Restrained	Hindered/Restrained

Pick from one of five native gravities columns, and add it under Origin on your character sheet. If you have chosen Microgravity or Very Low gravity, you will see that for certain situations, such as on a planet or during high acceleration of over 8g, the Dying condition may be applied, but GMs would be wise to consider changing the conditions from rounds until death to minutes until death.

Note on Earth gravity: it may be worth changing the penalty in Very low g to -2.

Also, some will be quick to notice that the heavier gravities cover a larger range of gravities. A character native to heavy gravity shouldn’t necessarily have that much of an advantage in very heavy gravity. Thus, going into a very heavy gravity environment may still cause the Hindered condition (particularly if it is towards the upper end of the range). Another option is to expand the table with a row for each g above 2.

Origin and native gravity

• Microgravity: The character has grown up on a station similar Pallas, or on a ship that spends most of its time on the float. The character is unaccustomed to physical activity under any kind of gravity, and suffers penalties from the slightest of accelerations and on most spin gravity stations (less than 0.1 g)
  • You automatically have the Dexterity (Free-fall) focus.
  • Natives to microgravity to be tall and willowy as a result of being raised in microgravity environments. Regimens of bone-density drugs and genetic treatments are needed to keep you healthy, and you may have minor physical abnormalities because of this.
• Low Gravity: The character has grown up on Mars, or a planet or moon with similar gravity. They are accustomed to weight and the notion of an “up” and “down” is natural. Deals with microgravity better than some, but it is not their natural state of being (0.31-0.8g).
  • Natives to low gravity are more comfortable in microgravity than people native to standard gravity, and more comfortable in standard gravity than people native to microgravity.
• Standard Gravity: The character has grown up on Earth or a planet or moon with the same force of gravity (1g, or slightly more or less).
  • Natives to standard gravity—”Earth-normal” or 1 g—you can learn to operate in lower gravity but lack the instincts of people raised in it. You have greater muscle and bone density, which also makes you shorter and of broader build than natives to lower gravities, but in space you need regular exercise and treatments to avoid muscle athropy and bone density loss.
• Heavy Gravity: You have grown up on a colony world with higher gravity than Earth (2 to 4g).
  • Natives to heavy gravity are shorter and stockier than all other native origins. Microgravity will always provide a challenge, removed as it is from a orderly sense of up and down. In space you need regular exercise and treatments to avoid muscle athropy and bone density loss.
  • You automatically have the Strength (Might) focus. Additionally, you have a +2 to Constutition (Stamina) checks due to acceleration and high-g maneuvering.

• Very Low Gravity (optional, if you want this level of granularity of origin): The character has grown on a spin station like Tycho, a spun up asteroid like Ceres, or perhaps a moon like Ganymede. The character is somewhat unaccustomed to microgravity, the notion of an “up” and “down” is a reference point, they are more accustomed to physical activity under some gravity and acceleration (0.1 to 0.3).
  • Natives to very low gravity are far more comfortable in microgravity than people native to heavier gravities, but you lack the natural instincts of microgravity natives, you are also more comfortable in low and somewhat more in standard gravity, than people native to microgravity.

Designer note: Personally I would go for table 1 (and 2 if a player wants to play a character from a heavy gravity colony world), because it is more lenient for fun gameplay.