Chris Walker, a professor of astronomy at the University of Arizona, sent a proposal to NASA Innovative Advanced Concepts, which essentially says this: a giant inflatable beach ball may be turned into a space telescope.
This proposal was sparked by Walker’s serendipitous observation thirty years ago.
Walker was making chocolate pudding when he had to interrupt his culinary undertaking to field a phone call from his mother. He took the pudding off the stovetop, covered it with plastic wrap, and placed the pot on the floor by his couch. When the call was finished, he was startled to find an image of a light bulb from a nearby lamp hovering over the end of the couch. When he investigated the cause of this apparition, he found that a pocket of cold air formed as the pudding cooled, and that had caused the center of the plastic wrap to sag toward the pudding. This, in effect, formed a lens that was reflecting the light bulb.
In 2014, Walker and his students made the first prototype of the large balloon reflector out of a large inflatable plastic sphere sold by a Chinese toy manufacturer. The ball had been designed for people to climb around inside like a human-sized “gerbil ball,” but it also turned out to be pretty great for radio astronomy. Walker suspended an antenna inside the ball and sprayed a circle with metallic paint on the inside to create a reflector. With this rudimentary setup, Walker and his students were able to do radio observations of the Sun from the rooftop of the astronomy building at the University of Arizona. Even though it wasn’t sent to the upper atmosphere, Walker says it demonstrates that even a very crude version of the telescope could get good results. “I knew it would work, but you have to show people,” he says. “Nothing beats a rooftop demonstration.”
Image Credit: Chris Walker