Astronauts sent to explore Mars聽may be more sure-footed if their boots are fitted with microphones to help them hear their own footsteps, say the authors of research suggesting that sound is vital to our ability to step accurately.
The sound of a boot landing provides useful cues about the terrain, whether it is sandy, crusty or rocky, says at United Arab Emirates University. But spacesuits stop astronauts from feeling the ground under their feet and tend to muffle sound. The Apollo moon missions recorded 27 falls and 21 near falls, which were partly attributed to difficulty reading the terrain.
Berengueres and his colleagues have previously worked on haptic feedback devices that record information about the texture of the ground and relay it through thick boots to motorised devices inside the boot. But Berengueres says that a lighter, cheaper and potentially more intuitive method could be to simply fit microphones to the boots.
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He says there has been almost no research on sound feedback for astronauts, which is understandable for moon missions as there was no atmosphere there to transmit sound. But on Mars, it would theoretically be possible to hear our footsteps.
To measure how much our sense of sound contributes to our spatial awareness, the researchers turned to the Fukuda-Unterberger stepping test, which is usually used to assess the vestibular system 鈥� our sense of balance and movement. They asked 14 participants to march on the spot for 50 steps while blindfolded to see how far they wandered from their starting point. They found that people drifted 22.5 centimetres on average, but this rose to 37 centimetres if they wore sound-deadening headphones.
Berengueres says his experiments support the idea that relaying the sound of footsteps to an astronaut would reduce the risk of trips and falls. 鈥淎ll the data we have at the moment indicates it would, but how much of an improvement at the end of the day that represents, we don鈥檛 know. But anything you do to improve safety, even 1 per cent, I think is worth exploring, especially if it鈥檚 a cheaper or lighter option than haptics,鈥� he says.
Berengueres has carried out initial experiments with microphones fitted to shoes, but wants to get hold of a real spacesuit to run realistic tests. 鈥淚t鈥檚 so amazing to walk with microphone sound directly, which is very clear and without a lot of noise from other sources. You really feel as if you were seeing with a big lens what you鈥檙e stepping on,鈥� he says.
Sounds on Mars would need a lot of amplification, however: because the density of the atmosphere is 1.6 per cent that of Earth鈥檚, a noise produced by a footstep on Mars is 85 times quieter than on Earth.
at Baylor College of Medicine in Houston, Texas, says humans are usually unaware of how much sensory information they are using just to navigate their environment. 鈥淵ou鈥檙e using your hearing, your vision, your neurovestibular system, your touch, your proprioception,鈥� she says. 鈥淭here鈥檚 a lot of sensors built into our bodies that I think we kind of take for granted at any one time.鈥�
On Earth, our visual and tactile senses work well enough that hearing probably isn鈥檛 vital, she says, but things might be different in space. 鈥淪o if you can bring back something like hearing your footsteps, maybe it is of added value.鈥�
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