The space shuttle Challenger is getting another chance to produce snow.
The project began when Tokyo's mass-circulation newspaper Asahi Shimbun asked its more than 12 million readers to suggest an experiment that it could sponsor on the sixth shuttle flight last April.
The newspaper's readers submitted 17,000 ideas, and Asahi chose a scheme by two Japanese high school boys to make artificial snow in space.
Their experiment was aboard Challenger's maiden space flight in April, but failed because the temperature inside the canister where snow crystals were to grow was too cold. The experiment resulted only in ice, at a cost to Asahi Shimbun of $340,000.
Asahi asked Japanese engineers to redesign the project, and the rebuilt canister is aboard Challenger again, making a reappearance right now on the eighth shuttle flight, the third time Challenger has been in orbit around the Earth.
The engineers installed a tiny fan at one end of the canister to circulate water fed as vapor into a second canister that was cooled to 5 degrees below zero Fahrenheit.
Engineers suspect that the lack of a fan the first time was the reason the water turned into ice instead of snow.
When the water vapor reaches the ice box, a small heater is turned on that seeds it with silver iodide, the same chemical crystals that are used in rainmaking in clouds during droughts.