After 13 years of hauling hundreds of pieces into space and almost 200 spacewalks to connect them, NASA and its 14 international partners have opened the biggest—and costliest—scientific laboratory ever to orbit Earth. NASA estimates the United States alone has put in $48.5 billion. Now the world is waiting to see whether the science conducted aboard the International Space Station will be as extraordinary as its engineering.

Weighing in at 450 tons, the station has the pressurized volume of one and a half Boeing 747s and boasts an acre of solar arrays, which generate 700,000 kilowatt-hours of electricity a year, enough to power 50 homes. NASA will use its share of that capability to learn about space travel, space technology, and the effects of prolonged spaceflight on the human body—all areas of prime interest in plans to eventually send astronauts to Mars.

But there’s capacity left over, and U.S. scientists who want to fly their experiments in space no longer have to go through either NASA or one of the international partners to make that happen. Now there’s a new point of entry into the U.S. Destiny lab: through the non-profit Center for the Advancement of Science in Space (CASIS). Last August, NASA signed an agreement with the center for it to develop and manage about half of the U.S. share of the station, which Congress in 2005 designated as a National Laboratory, the 17th U.S. facility so named. Filling it with new experiments is “not going to happen instantaneously,” says NASA’s Mark Uhran, director of the International Space Station division and the man in charge of the transition from station construction to station use. But with the CASIS agreement in place, he says, NASA “looks forward to a gradual and consistent expansion” of research aboard the ISS.

The research NASA is now conducting—through collaborative agreements with such organizations as the Department of Agriculture, the National Institutes of Health, and the Defense Advanced Research Projects Agency—advances NASA’s mission in space exploration, says Uhran. What CASIS will oversee in the National Laboratory, he says, “will have both peer-reviewed basic research and market research with private firms.”

With one important distinction: “The idea is to develop products to help benefit Earth,” says the center’s executive director, Jeanne Becker, a cell biologist whose experiments have flown on the space shuttle. “The agenda will be multidisciplinary, but the emphasis will be on using the space environment to make life better here.”

The center, located in the Space Life Sciences Laboratory at Florida’s Kennedy Space Center, will receive from NASA $15 million per year for the next 10 years, and will both make its own grants and oversee installation of other experiments that have their own resources. Priorities in such fields as biomedicine, life sciences, and material sciences will be set by a 15-member board, with members serving for three years, Becker says. The center plans to issue its first solicitation for research proposals this fall.

WITH THE STATION OPEN for business, both traditional users, like NASA scientists and their partners, and innovators from academia or industry have begun planning expanded research programs.

John Charles, chief scientist for NASA’s Human Research Program, has been waiting since 2003 to use the station as an analog for a spacecraft transit to Mars. “It’s very high-fidelity,” he says. “You have isolation, weightlessness, canned food, risk of decompression, and at the same time you’re trying to do meaningful work.” Charles and his team have begun crafting a 2013 project that will ask station astronauts to do a dozen ordinary tasks while coping with delays of several minutes in their communications with mission control. Radio transmissions from Earth would take more than 20 minutes to reach astronauts on Mars.

“We don’t want to spring the delay on them suddenly and see what happens,” says Charles. “We want to spend a lot of time thinking about texting, instant messaging, and any other way astronauts can have a written record to help them work around the delays. Then we’ll see.”

Among the innovators is the Massachusetts Institute of Technology’s Space Systems Laboratory, with its unique SPHERES experiment. Few tools better advertise the station’s capabilities than SPHERES. Three soccer ball-size spheres—duododecahedrons, actually, formed by 24 flat polygons—float like large golden orbs in a Harry Potter-like game whenever they are released inside the station. Each ball has carbon dioxide thrusters that allow it to move up and down, side to side, in a circle, a spiral, you name it—as long as you program it with the right software. You can use one ball as if it were a single spacecraft, two if you want to dock them, or all three if you’re interested in formation flight. Astronauts can joystick them from a laptop, or the balls can be programmed beforehand and simply put to work.