Mimicking Gravity in Space
- Kayana Kalyca
- Jan 4
- 4 min read
Can humans survive without gravity? Considering the fact that you can lose up to 20% of your muscle mass in space in just the first five days, being in zero gravity provides adverse effects to the body. This includes the loss of bones from negative calcium balance, certain muscle atrophy (the loss of muscle mass), reduced volumes of plasma in the body, and worsening of cardiovascular functions (Wolfe & Rummel, 1992). This is where we introduce artificial gravity. As written in a research by Bukley, Paloski and Clément (2006), artificial gravity is the simulation of gravitational forces aboard a space vehicle in free fall or in transit to another planet, reserved for a spinning aircraft or centrifuge within the spacecraft that creates a gravity-like force.
How Does Artificial Gravity Work?
There are multiple ways of generating artificial gravity. Methods of producing it include rotation, linear acceleration, and making use of magnetic fields.
The most notable on the list is rotation through the use of centrifugal force. Artificial gravity is not actually gravity. It is the force of inertia where a body is being centripetally accelerated in a rotating device (Bukley et al., 2006). The centrifugal force acting on this body is proportional to its mass and the artificial gravity generated is directly proportional to the square of angular velocity and the radius of this device (g=ω²r). Artificial gravity is created when the object is rotating about its center of gravity. In space, it could be generated by spinning a spacecraft about its axis or rotating two spacecrafts interlinked via a tether. By centripetal acceleration, objects inside the spacecraft would be forced towards the outer radius, resulting in gravity.
When using rotation to create artificial gravity, it is important for the structure of the device to be stable, by not only being strong enough to resist pressure of the rotations but having mass uniformly distributed throughout the device to avoid unsteady movement. It is also important to make sure that the rotating device has a large enough radius as high rotation speeds bring the effect of coriolis forces and variation in gravity. The coriolis effect is when objects traveling around a circular path look like they are curving instead of travelling in a straight line. The forces produced in this spinning environment may cause dizziness, where a large radius would reduce.
It seems to me a bit like you aren’t so sure yourself how this works? But whether or not you do, this paragraph could use with some development & illustrations.
Another method of producing artificial gravity is through linear acceleration. Applying Newton’s third law of motion, the sensation of gravity is produced when containers like spacecraft are continuously accelerated in one direction. The objects inside it are forced in the opposite direction of that applied acceleration. The amount of gravity produced is dependent on the acceleration. For example, when acceleration is equal to Earth’s acceleration due to gravity (9.8 m/s²), gravity too will be equivalent to that of Earth’s. This method is not an efficient or practical method in producing artificial gravity, however, due to the limitations of fuel that can be carried on the spacecraft to power accelerations.
Lastly, artificial gravity can be produced using magnetic field gradients. According to Beysens (n.d.), high frequencies and low amplitudes can be used as artificial gravity in space. Due to the phenomena of thermal convection, interface localisation, and phase separation, the vibrations induce mean flows that closely mimic buoyancy. The use of these vibrations were recently implemented by astronauts, vibrating their legs and feet to lower the risks of muscle decay or bone decalcification. However, similar to using linear gravity, the cost of energy for using magnetic fields is extremely high.
Applications of Artificial Gravity
Apart from preventing muscle decay or bone decalcification for astronauts, artificial gravity is used for a variety of things. Artificial gravity is widely used in space. They’re especially beneficial for long term missions such as scientific experiments, asteroid mining, deep-space exploration, and even space tourism. Artificial gravity is essential to provide astronauts with stability when working in space and as human bodies cannot tolerate being totally weightless. Alternatively, artificial gravity is applied in the medicine field. As the lack of gravity is often associated with pathologies in the musculoskeletal system, cardiovascular deconditioning, brain abnormalities, and more, as shared by Isasi et al. (2022), artificial gravity is applied to short-arm human centrifugation (SAHC) to treat these conditions. SAHC is a technique that offers researchers an enhanced method of discovering the impacts of increased gravity by stimulating gravitational forces on the body (NASA, n.d.). Later, this technology is also used to treat mental health illnesses.
References:
Bukley, A,, Paloski, W. & Gilles, C. (2006). Chapter 2. Physics of Artificial Gravity.
D. Beysens, (n.d.). Vibrations in Space as an Artificial Gravity.
G Clément, A Bukley, (2007). Artificial gravity. Google Books.
Isasi, E., Isasi, M. E., & Van Loon, J. J. W. A. (2022). The application of artificial gravity in medicine and space.
Frontiers in Physiology, 13. https://doi.org/10.3389/fphys.2022.952723
NASA. (n.d.). M1 short-arm human centrifuge. NASA. Retrieved December 8, 2024, from
Smith, P. (n.d.). Artificial gravity. A Star Maths and Physics.
What is the Coriolis effect? (n.d.-b). NOAA SciJinks – All About Weather. https://scijinks.gov/coriolis/
Wolfe, J. W., & Rummel, J. D. (1992). Long-term effects of microgravity and possible countermeasures.
Advances in Space Research, 12(1), 281–284. https://doi.org/10.1016/0273-1177(92)90296-a
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