Scientists have created wearable vibrotactile devices to help astronauts stay oriented and safe in space
Astronauts usually undergo extensive training to protect themselves from disorientation. However, researchers have recently discovered that wearable devices that provide orientation cues through vibrations can greatly enhance the effectiveness of this training.
“Long duration spaceflight will cause many physiological and psychological stressors which will make astronauts very susceptible to spatial disorientation,” said Dr Vivekanand P. Vimal of Brandeis University in the United States, lead author of the article in Frontiers in Physiology.
“When disoriented, an astronaut will no longer be able to rely on their own internal sensors which they have depended on for their whole lives.”
Using sensory deprivation as cues
The researchers conducted experiments using sensory deprivation and a multi-axis rotation device to assess the effectiveness of vibrotactors in a simulated spaceflight environment where the usual sensory cues were unavailable.
They aimed to determine if the vibrators could counteract the misleading signals that participants might receive from their vestibular systems and whether participants could be trained to trust these artificial cues.
The study
A total of 30 participants were enlisted for the study. Among them, ten individuals received training specifically for balancing in the rotation device, another ten were provided with vibrators, and the remaining 10 received both types of training. All participants were shown a video demonstrating the operation of the rotation device.
For those participants who received additional training, it involved tasks designed to encourage them to disengage from their natural vestibular senses and rely instead on the vibrotactors, effectively disregarding their innate gravitational cues.
These tasks entailed locating concealed non-upright balance points, requiring participants to resist their inclination to align themselves upright and concentrate on responding to the cues provided by the vibrators.
All participants had blindfolds, earplugs, and white noise to block their sensory inputs. Those provided with vibrators had four of these devices strapped to each of their arms, vibrating when they deviated from the balance point. Each participant underwent 40 trials to maintain the rotation device close to the balance point.
During half of the trials, the rotation device operated on a vertical roll plane, which resembled Earth’s conditions, allowing participants to rely on their innate gravitational cues for orientation. In the second half, simulating a spaceflight scenario, the rotation device operated on a horizontal roll plane, where these gravitational cues were no longer applicable.
Relying on gravitational cues
In the spaceflight simulation, all groups initially experienced disorientation, as they couldn’t rely on their usual gravitational cues. While most participants trusted the vibrators, they also felt confused by conflicts with their internal cues.
The vibrator-wearing group outperformed those with training only, who had more crashes and balance issues. The combined training and vibrator group performed the best over time. However, participants still didn’t perform as well as they did in the Earth-like simulation.
If the sensors prove effective in broader testing, the potential applications in spaceflight are numerous. These applications range from aiding astronauts in safe planetary landings to providing support during extravehicular activities in space.
