As principal investigator, space crystallographer, and biochemist, Alexander McPherson, of University of California, Irvine, and colleagues have been flying this experiment since September 1984, when they were guest investigators with University of Alabama researchers. In ensuing years, their experiments flew on seven shuttle missions to the former Russian space station Mir, including the first American mission, as well as numerous other shuttle missions—all without student involvement.
The goal of the long-term experiment is to determine the three-dimensional structures of various selected proteins—including thaumatin, pea lectin, canavalin, Bence-Jones, and various viruses—by X-ray diffraction analysis and other techniques. Determining these structures could lead to new drug designs, among other advances. "We need crystals to do that," says project scientist Stan Koszelak, also of UC-Irvine. "And in the microgravity of space, the crystals are not weighed down by the force of one gravity, [but are] free to diffuse slowly and evenly" in three dimensions. "As a result, we get better crystals in space, and that gives us more precise images of the molecules." Those images are rendered as three-dimensional computer models for study.
Numerous tests of each protein in space, are required, however, to get those kinds of models, so there are "literally hundreds of samples," McPherson points out. "There could even be thousands of samples if we really pushed it. We needed to get more hands helping us."
As Mir shut down and the ISS was under construction, an idea sparked. "It occurred to us that we could turn this into a student experiment," McPherson recalls. "Preparation of the samples is so simple and there are so darn many samples—why not try to engage students who would otherwise not have the opportunity? We decided to target primarily disadvantaged schools, from the inner city of Los Angeles to schools in the South so far out in the boondocks that no sunlight ever gets to them." It was such an appealing concept all the way around that NASA, along with industry partners and space grant consortia, took over the logistics of securing the students. That was three years and four flights ago.
From the beginning, the teachers have been "thrilled" with the program, says Raymond French, project manager for the experiment at NASA's Marshall Space Flight Center in Huntsville, Ala. "It's not standard curriculum and it gets the students excited—which is so hard to do these days. We're hearing that the program has actually changed some lives ... some of these students are persuing careers in science." Since their first student-assisted flight, the program has become "wildly successful," McPherson says.
Teachers and students undergo training at special workshops to learn what they're working on and how to load the tubes. "It's very carefully regulated," explains McPherson. "We don't just turn the kids loose to make a bunch of stuff we send up into space. The students work under our supervision, and we inspect every sample they do."
Once the samples are capped inside their tubes, they are loaded into Dewars, specially designed containers cooled by liquid nitrogen. The Dewars are then loaded onto the orbiter. A limited number of students get to travel to Cape Canaveral to watch the launch.
During the last several years, McPherson and colleagues have "completed the picture," as Koszelak puts it, for satellite tobacco mosaic virus and, in cooperation with Russian researchers, leghemoglobin. The crystalline structures of other proteins are in different stages of the process.
"We're not ourselves space scientists," says McPherson. "We're molecular biologists and biochemists, and that's what we're principally interested in, but we can use space to inspire students to become interested in science by providing this opportunity." One of the grandest rewards, he adds, is that "the students we reach in this program are the ones who need it the most."