Northwestern Prof. Peter Voorhees is getting his research ideas off the ground.

Voorhees’ research experiment, “Coarsening in Solid-Liquid Mixtures,” has been chosen by NASA to fly on the International Space Station this September.

“We’ve been very lucky,” said Voorhees, a materials science professor. “You go through a long and torturous review process to get your ticket to fly.”

The experiment measures the effects of heat on a mixture of a metal alloy and a liquid in microgravity. Alloyed metals, such as those used in high-temperature turbine blades in jets, undergo a process called coarsening: over time, small particles in the metal shrink and large particles grow, causing the metal to weaken.

Working with NASA in space puts a lot of pressure on the experiment to succeed, Voorhees said.

“You only get one chance, because it costs so much money,” he said. “That’s the really scary thing. You can’t just turn the nob this way or that way and try it again, like on the ground. They’ll say ‘Sorry, well tough.'”

Voorhees said he is grateful to NASA for giving him the opportunity to try his experiment in space, especially since the space station faces drastic spending cuts. Under President Bush’s proposed 2003 federal budget, NASA would get a $500 million boost to about $15 billion, but the space station would lose about $230 million from its current $1.7 billion budget.

One of the items being sacrificed is an emergency crew return vehicle, so only three astronauts can stay in the station, instead of six.

“Only 20 hours a week is devoted to science, because they are kept busy with housekeeping duties,” Voorhees said. “They are still in the process of building the station.”

Voorhees’ space station experiment will try to measure how fast the metal weakens by heating it in a special furnace built by NASA engineers. When the experiment comes back to the ground, Voorhees and researchers will cut open the cooled chunks of metal and see what happened to the particles.

Voorhees says his data will be of interest to companies who want to ensure their materials are strong and safe.

“GE might do their own experiments, but they can’t predict how fast coarsening will occur,” he said. “This might help eliminate guesswork. They want to know the optimal particle size for strength.”

The conditions in space are far superior to those on earth because of microgravity, Voorhees said. If the experiment took place on earth, the particles would separate with small ones floating to the top, and larger ones sifting to the bottom. In space, the different sized particles will be evenly distributed, and this is much closer to the theoretical conditions of coarsening.

Voorhees likens the coarsening phenomena to Italian salad dressing: when it settles, all the oil floats at the top, and the vinegar and chunks of seasoning rest at the bottom. This is called a coarse mixture. In space, one would never need to shake up salad dressing because the oil and vinegar would be all mixed together.

The experiment will run during the astronauts’ sleeping hours because still conditions are necessary for the measuring instruments. Astronauts jogging on a treadmill would affect the center of mass of the entire space station.

If the experiment goes according to plan in September, it will run again nine months later, and then nine months after that.