ISS Astronauts Fire-Up Awesome 'Cubesat Cannon'
astroengine writes "As if the International Space Station couldn't get any cooler, the Japanese segment of the orbiting outpost has launched a barrage of small satellites — known as "cubesats" — from their very own Cubesat Cannon! Of course, the real name of the cubesat deployment system isn't quite as dramatic, but the JEM Small Satellite Orbital Deployer (J-SSOD) adds a certain sci-fi flair to space station science."
I just pictured a cannon firing weighted companion cubes. But their picture is cool too.
They use springs. The J-SSOD click through in the article has a lot more information on the inner workings of the contraption. Its more like a nerf gun than a cannon. http://iss.jaxa.jp/en/kiboexp/jssod/