How is Artificial Gravity Achieved Inside a Spacecraft or While Traveling in Outer Space?

The term "outer space" is generally just a fictional writer's description or depiction of spacetime, as spacetime itself is a real entity. Similarly, artificial gravity does not actually exist. Artificial gravity, in the simplest terms, is the creation of a sensation that mimics gravity inside a spacecraft through various means, but it’s not the actual gravitational force. It’s the result of Newton's First Law of Motion. When a spacecraft rotates at a certain speed, it creates a centrifugal force that mimics the effect of gravity.

Generating Artificial Gravity Through Constant Acceleration

The easiest method for creating artificial gravity is to maintain a constant acceleration. This is achieved by continuously applying thrust to the spacecraft to simulate the feeling of gravity. In a spacecraft, this is akin to the ground pushing up on you. This method is simple and does not require rotation. However, there are downsides:

High Fuel Consumption: Maintaining this constant thrust is extremely fuel-intensive. For low gravity environments like Mars (with gravity equivalent to about 1/3g) this would necessitate an enormous amount of fuel. No Anytime Suspension: The artificial gravity would cease the moment the engines stop, which might be needed in scenarios where the ship needs to slow down or change direction.

Since the Expanse provides a fictional depiction of this method, we can see how it might work in practice. Ships in the Expanse are designed like tall buildings, with the engines at the bottom. Efficient engines keep the ship operating without an excessive amount of fuel.

Generating Artificial Gravity Through Rotation

A more efficient method involves rotating the spacecraft to create a centrifugal force that mimics gravity. However, this method also comes with its own set of challenges:

Dependence on Distance from Axis: The closer you are to the center of rotation, the less the centrifugal force (or gravity) you experience. Coriolis Effect: At rotations a bit above 1 RPM, the Coriolis effect becomes significant. This effect makes everything seem to curve or float in ways that deviate from usual expectations, making it difficult to throw balls in a straight line. For Martian gravity, you’d need a radius of about 336 meters. Engine Efficiency: High rotation rates can cause dizziness, and the ship would need to rotate at a rate less than about 1 RPM to avoid this. However, if you’re willing to wait for visitors to adjust, you can rotate as fast as 4 or 6 RPM.

Concluding Thoughts

Both methods of creating artificial gravity in spacecraft have their pros and cons. The selection of a method would largely depend on the mission requirements and the resources available. While the rotation method requires more initial setup but maintains a semblance of gravity for extended periods, the constant acceleration method is simpler but requires continuous efforts to maintain fuel supplies. The depiction of artificial gravity in The Expanse offers valuable insights into the practical applications and potential drawbacks of both methods.