Based on the recommendation of a “collegium” of scientific advisers, Casis is seeking proposals for “advancing protein crystallization using microgravity.” Scientists have long X-rayed protein crystals to learn the structure of the protein molecules, which allows them to design drugs to inhibit diseases associated with a particular molecule. But, because of the effects of gravity, protein crystals produced on the ground are often of such poor quality that they are essentially useless for the research, according to Larry DeLucas of the University of Alabama in Birmingham. DeLucas flew protein-crystal growth experiments on the space shuttle as a payload specialist, and continues the search for new drugs using protein crystals at a specialized laboratory in Birmingham.

Because of the relatively short flight time on the shuttle and other factors, even the crystals produced there were frequently unusable. But “the ISS offers a unique opportunity,” DeLucas says. “We have time for these crystals to grow.”

To illustrate the commercial potential of the ISS as a protein-crystal growth platform, DeLucas notes that of the more than 21,000 protein crystals produced under a $350 million long-term National Institutes of Health (NIH) initiative, less than 27% were of a quality high enough to determine their structures.

“That leaves over 15,000 proteins that NIH investigators know how to crystallize, but can't figure out how to get good enough crystals to determine the structure,” he says. DeLucas notes that among the medicines developed using protein crystallography is the “cocktail” of drugs that has dramatically increased survival rates among AIDS patients.

Results like that from ISS research will help recover the investment in the space station, NASA managers say. But for now, ISS research remains at a “tipping point,” says Gerstenmaier, and could go either way.

“We don't have a lot of time,” he says. “Ten years is not a long time to really get some breakthroughs and push some things. We have to take maximum advantage of that . . . . That's your challenge; be creative and push. Make me uncomfortable and make me nervous. Ask for new things, and then we'll see what we can really go do with this wonderful space station.”

Editor's note: This text has been modified to correct the name of the organization sponsoring the ISS users conference.