FOR astronauts living on the International Space Station, it鈥檚 vital to know
which way to head in an emergency. But when there鈥檚 no 鈥渞ight way up鈥� 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鈥檚 sense of balance鈥攄riven by cues from the
vestibular system in the inner ear鈥攇ets hopelessly confused. Experiments
on the 鈥渧omit comet鈥� 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 鈥渧ertical
inversion鈥濃�攚hen the brain suddenly tries to convince you that you鈥檙e
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鈥檛 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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鈥淚n an emergency, you need to know where you are quickly,鈥� he says. Liu
worries that although astronauts receive intensive training to familiarise
themselves with the station鈥檚 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鈥攖hanks 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鈥檛 when quizzed about the layout of the space station. But a third of
people in the study couldn鈥檛 navigate at all, no matter how hard they tried.
鈥淪ome people just don鈥檛 get it,鈥� says Liu.