A one way trip to the Red Planet would take up to nine months. During that time, astronauts on board the Mars-bound spacecraft could lose their sense of direction and ability to know up from down, making it difficult to orient themselves on the Martian surface. In order to keep astronauts on course, a wearable device could be used to improve their spatial orientation—but only if they learn to rely on external sensors when their own internal senses fail them.
As a research scientist focused on human spaceflight, Vivekanand Vimal has spent years exploring whether technology can be used to augment the senses of astronauts so that they can overcome their biological restraints on another world. “Our biology wasn’t made to be able to deal with space exploration and all these intense maneuvers,” Vimal told Gizmodo. “And so you have human augmentation, using technology to enhance our abilities where otherwise it would not work as well.”
Vimal, a researcher at Brandeis University’s Ashton Graybiel Spatial Orientation Lab and author of a new paper published in Frontiers in Physiology, studies the human vestibular system, which is a cluster of tiny structures inside the inner ear that we rely on for balance. On Earth, gravity pulls on the system’s otolith organs, little hairs with crystals on them, which tells you how far you’re tilted from your balance point. In space, however, the absence of gravity leads to astronauts being disoriented.
“Astronauts in microgravity, they’re not going to have a clear sense of where up is as they’re descending down because they don’t have a strong sense of gravity,” Vimal said.
Using a multi-axis rotation device that he had designed, Vimal tested a wearable device, known as vibrotactors, in simulated spaceflight conditions. Through a series of experiments, Vimal found that the vibrotactors could help astronauts fight spatial disorientation if combined with special training that allows them to rely on a machine rather than their natural gravitational cues.
The vibrotactors use vibration cues while strapped onto astronauts’ arms to indicate where they are in their environment, whether it’s upside down or tilted to the side. At the lab, around 30 people were blindfolded and attached to a rotation device with a joystick in one hand to try to balance themselves in an upright position. Those taking part in the study were split into three groups, one riding the simulator device with no help, another having the vibrotactors attached, and a third with both.
Some of the study participants were given additional training to help them disengage from their inner senses. So, instead of starting with a balance point right at the center, their starting position was randomized each time, which forced them to trust the vibrating device to tell them where they are in space rather than trying to use their instinctive gravitational cues. Due to their specialized training, this group performed much better than the others.
Although the group that trained with the vibrotactors said that they trusted the device, they still experienced conflict between their internal cues and the vibrations felt on their arms. As a result, they still didn’t trust the device enough to rely on it instinctively in a high-pressure situation such as landing a spacecraft. “Just because you cognitively trust these devices, it doesn’t mean you rely on them because in order to use them, you have to make gut level decisions really fast,” Vimal said. “You need to build a gut level, subconscious connection between human and device.”
The training program did not reduce the feeling of conflict, but it did allow the participants to overcome it. This type of training could help astronauts make better use of the vibrotactors during gravitational transitions such as take-off and re-entry of a spacecraft, or landing on the surface of the Moon or another planet like Mars where natural gravitational cues would have adapted to being in a weightless condition.
“After long duration flights, astronauts have postural instability, difficulty balancing…they’re very wobbly,” Vimal said. “It’s hard for them to balance because they have to almost basically rewire their brain again to deal with gravity.” By using the vibrotactors, astronauts could perform more accurate maneuvers with the spacecraft while landing on the lunar surface by having a better sense of what’s up and what’s down.
For the next phase of his experiments, Vimal will also implement lunar and Martian gravitational levels on the rotating device to simulate being on the surface of another world. “In our next paper, we will create Martian and Lunar analogs where there will be some gravitational cues,” he said. “Overall, we are interested in determining what factors lead a human to feel completely merged with a sensory augmentation device.”