FOR astronauts living on the International Space Station, it’s vital to know
which way to head in an emergency. But when there’s no “right way up” and the
floor could just as easily be the ceiling, getting your bearings quickly is no
mean feat. So to train astronauts and future space tourists, scientists have
developed a virtual reality space station.
In microgravity, the body’s sense of balance—driven by cues from the
vestibular system in the inner ear—gets hopelessly confused. Experiments
on the “vomit comet” aircraft that NASA uses to simulate weightlessness have
shown that rats get lost far more easily in these conditions than on the ground.
Astronauts also report losing their bearings after “vertical
inversion”—when the brain suddenly tries to convince you that you’re
upside down, even though that has no meaning in space.
Astronauts try to compensate for the confusion and disorientation of
weightlessness by visualising their entire environment as a whole in three
dimensions, rather than just remembering that a certain passage leads to a
specific module. But it isn’t easy, and getting it wrong could be serious, says
Andy Liu of the Man Vehicle Laboratory at the Massachusetts Institute of
Technology.
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“In an emergency, you need to know where you are quickly,” he says. Liu
worries that although astronauts receive intensive training to familiarise
themselves with the station’s layout, few would-be space tourists would be able
to accurately visualise and rotate an object like the ISS, which has eight
modules linked at different angles, to get their bearings.
A virtual-reality system developed by Liu and his student Jessica Marquez
could help. Trainees hold a model of the ISS that doubles as a joystick for
getting around the virtual station. If they lose their way, a flick of a switch
brings up a 3D image of the ISS on a screen in front of them. By rotating the
model in their hands they can rotate this image—thanks to ultrasound
transmitters built into the model and detectors fixed overhead.
Liu says the system will give people practice in visualising themselves as
they move around and will help them work out mental strategies for route-finding
in space. One strategy, for example, is to remember distinctive corners and
groups of objects that form triangles, rather than whether things are on the
floor or the ceiling.
Astronauts are due to try the system early next year. In ground-based tests,
people trained on the virtual system made half as many mistakes as those who
weren’t when quizzed about the layout of the space station. But a third of
people in the study couldn’t navigate at all, no matter how hard they tried.
“Some people just don’t get it,” says Liu.