The World's Highest Laboratory
The space station's finished. Now what?
- By Guy Gugliotta
- Air & Space magazine, March 2012
(Page 2 of 5)
“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.
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.