Extended stays in microgravity pose severe health risks to astronauts, including vision deterioration, bone density loss, and muscle atrophy. While artificial gravity remains a staple of science fiction, ranging from the rotating habitats in “2001: A Space Odyssey” to modern concept designs, researchers argue the technology could soon become a reality for long-haul spaceflight.
“There’s really no reason it couldn’t happen,” said Torin Clark, an associate professor of aerospace engineering at the University of Colorado Boulder. “From a technical perspective, this is something that could happen in the very near future.”
Despite the technical feasibility, artificial gravity has faced repeated cancellation. In 2005, NASA aborted the Centrifuge Accommodation Module, an 8.2-foot-wide device intended for the International Space Station (ISS), due to budget cuts. Ana Diaz Artiles, an associate professor at Texas A&M University, described this as a recurring pattern in the field.
“It’s one of those things — like all of a sudden, it’s super popular, and then all of the scientists at NASA and everybody have a lot of funding to understand how to actually implement this, and then it just dies,” Diaz Artiles told Live Science. “And then it comes back, and dies, and comes back. I’ve been going through a couple of these cycles in the time that I’ve been doing this.”
Beyond funding, significant engineering and physiological questions remain unanswered. “Everybody agrees it’s a good thing to do. The problem is that we don’t know how to implement it,” Diaz Artiles noted. Key uncertainties include the required gravity level, the necessary size of the device, the duration of exposure, and whether continuous or intermittent use is more effective.
Scientists are currently evaluating three primary methods for generating artificial gravity:
- Rotating Large Structures: This classic approach involves a giant ring that rotates the entire living and working quarters of a spacecraft. While a long radius allows for slower rotation speeds, the structure is massive and would require multiple spacecraft launches and complex in-orbit assembly.
- Short-Radius Centrifuges: More practical than full-scale habitats, these devices resemble tubes with a radius of 6 to 10 feet (1.8 to 3 meters). Astronauts would spend short daily sessions inside, similar to exercising on a treadmill, with their heads closer to the center of rotation to simulate downward pull toward their feet.
- Linear Acceleration: This method relies on continuous thrust to push astronauts into their seats, mimicking Earth’s gravity. The spacecraft would flip and fire thrusters in the opposite direction during deceleration to maintain consistent gravitational force. However, Diaz Artiles pointed out that current propulsion technology is not yet capable of sustaining such acceleration.
The short-radius centrifuge is considered the most viable option from both cost and engineering standpoints, but it introduces the risk of motion sickness. The Coriolis effect can cause a disorienting sensation of tilting or tumbling when users move their heads off-axis in a fast-spinning environment.
Clark and his team have found that humans can acclimate to these sensations through gradual exposure. “If you very slowly, incrementally increase the spin rate… as far as we could tell, anyone can be made to incrementally acclimate to the rotating environment up to 20 to 30 rotations per minute,” Clark explained.
However, determining the exact prescription for health benefits remains difficult. While bed rest studies simulating spaceflight deconditioning suggest that 30 minutes of daily centrifuge use can preserve muscle function, Clark suspects this may be insufficient. “Maybe an hour or even two hours a day, and maybe at higher G levels, would be beneficial,” he said.
Ultimately, the barrier to implementing artificial gravity is not technological capability but rather a lack of comprehensive data and political will. “We know how to do this. As humans, we have done more difficult things,” Diaz Artiles concluded. “We need the money, but we also need to better understand the need.”
The dosage uncertainty is frustrating. Until we know exactly how much gravity astronauts need daily, budgets will stay tight.
Linear acceleration is still sci-fi territory with current propulsion tech. Let’s focus on what’s actually buildable in orbit first.
Short-radius centrifuges seem like the most practical near-term solution. Why hasn’t NASA prioritized this over other expensive projects?
Motion sickness from the Coriolis effect sounds brutal. Can humans really acclimate to that, or will it just make missions miserable?
I hope we finally break this cycle of funding cancellations. The health risks of microgravity are too severe to ignore for long.