SPHERES—for Synchronized Position Hold, Engage, Reorient, Experimental Satellites—is the brainchild of MIT’s David Miller and has been aboard the station since 2006. It is used by the Department of Defense, NASA, and private aerospace companies to assess the feasibility of new maneuvering techniques in space by testing them in microgravity—but in miniature. Can a spacecraft dock with a tumbling piece of space junk? Yes. Simply program one sphere to roll around and simulate a derelict satellite. Then program another to dock with it—without crashing—and bring it down to Earth’s atmosphere, where it can burn up.
“We don’t tell you what kind of spacecraft to build,” says MIT aeronautical engineer Alvar Saenz Otero, the experiment’s chief scientist. “We build the software that makes it possible to do what you want to do. Nobody had ever docked in space with a tumbling object before.” A tool for today’s space age, SPHERES is able to provide practical demonstrations of how engineering theory works in actual microgravity.
Beyond its focus on Mars-applicable technologies, NASA will be looking for more innovations like SPHERES, a project that will grow more useful as time passes. Using the SPHERES-tested software, mission planners may one day program spacecraft to dock on their own. Controllers in the future can fly a suite of telescopes in formation, shifting them and re-pointing them as perspectives on the cosmos change. As interest mounts in servicing satellites in space or de-orbiting dead spacecraft, SPHERES docking techniques can come into play. And as the threat of collisions with orbital debris increases, SPHERES technology can enable satellites to sense debris and stay out of harm’s way.
Also in place is the joint NASA-Canadian Space Agency Robotic Refueling Mission, in which a simulated satellite fuel module serves as a prop in practicing on-site refueling. Station crews will use the Canadian-built Dextre robotic arm to manipulate a set of special tools to tear off the insulation protecting the fuel tank (located on the outside of the station), unscrew the cap, and pump in a new load of (simulated) hydrazine fuel. The experiment’s operations began last September and will continue through 2013.
“This is a bottom-line benefit,” says Frank Cepollina, project manager for the Satellite Servicing Capabilities Office at NASA’s Goddard Space Flight Center in Maryland. “If you had this capability, you could extend the use of a satellite by refueling it, repairing it, or repositioning it, and by demonstrating it in space, we can go a long way toward removing the reluctance of commercial companies to do this kind of thing.”
Another path-breaking experiment is a forerunner to the type of research that CASIS will review. NASA is sponsoring University of Florida horticulturalist Wagner Vendrame, who is sending tissue samples from a wild, tropical, coffee-tree-size shrub called jatropha to be grown on the station. Identical sets of samples are being grown on Earth.
Scientists are interested in jatropha because it produces a fruit whose seeds yield an astonishingly pure oil that is an ideal source of biodiesel. “The problem is we don’t have commercial cultivars yet,” Vendrame says. “It’s a wild species and it’s like somebody found the first corn plant.” Jatropha may be a source of revenue for growers in the state of Florida, which, worried about winter freezes, citrus canker, and other threats to its groves, is looking for a profitable alternative to oranges and grapefruit. But jatropha’s early promise faded because of improper cultivation practices; in addition, there are too many varieties of the plant with too few desirable characteristics.
Vendrame is using his best plants on the station, and comparing the results with his ground samples, hoping to more quickly identify genes that produce the most oil. In traditional harvesting on Earth, many generations must be produced before a useful cultivar can be found. “Microgravity might accelerate the process,” he says. “We may be able to save 10 years.”
The station’s international partners are also planning Earth-focused activities. The Canada-based company UrtheCast has an agreement with the Russian space agency, Roscosmos, and aerospace company RSC Energia to launch and install a pair of Earth-observation cameras on the Russian side of the station this year. One camera will be fixed in place and point straight down, while a second, boom-mounted camera will be movable to focus on details, says UrtheCast president Scott Larson. Both feeds will be streamed on the Internet for free, but Larson says the company expects to make money by selling its raw data to other firms and organizations, and through advertising.
The European Space Agency has steadily expanded its station science agenda since the launch and installation of its Columbus laboratory in 2008. Columbus now has 150 projects under way and expects to move into experiments lasting much longer. “For us, it’s a steady evolution,” says Martin Zell, chief of ESA’s Astronauts and ISS Utilisation Department. “In our research into plant biology, immunology, neurophysiology, fluids and materials research, we are implementing several experiments where the new objectives are based on the results of previous experiments.” Like NASA, ESA is moving into studying the effects of prolonged spaceflight on the body.