ASTRONAUTS pedalling their exercise bikes risk wrecking expensive
microgravity experiments on the International Space Station because of the
vibrations they send rattling through the craft. So to protect delicate samples,
engineers have devised a miniature football-sized lab that will hold their
experiments suspended in mid-air.
Inside the microlab, six jets squirt precise amounts of gas to keep a bubble
of liquid or a chunk of solid centred in mid-air, well away from the walls. The
chamber will allow researchers to study how fluids behave in microgravity
without anything having to touch them, says Robert Gustafson of aerospace
company Orbitec in Madison, Wisconsin, which made the device.
An array of tiny microchip-based cameras pinpoint the sample鈥檚 position in
three dimensions and send signals to a microchip controller that regulates the
action and power of the jets. Gustafson says the device successfully handled
droplets of milk of magnesia in tests held last November aboard NASA鈥檚 鈥渧omit
comet鈥� aircraft, which follows a trajectory that provides short-lived low-g
conditions for training astronauts.
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Apart from the crew, other sources of vibration aboard the space station
include the air-cleaner in the Russian module, and shocks ringing through the
craft when the space shuttle docks. The plan till now was to run sensitive
experiments such as growing crystals during quiet periods, when all
non-essential equipment can be turned off and the astronauts barred from
exercising. 鈥淭he vibrations cause a major problem, and if we don鈥檛 have a
solution, a lot of experiments could be lost,鈥� says Chandra Ray of the
University of Missouri.