Japanese researchers discovered and published images taken by one of their satellites orbiting the Moon about 3 years ago. It depicted a large hole below the surface. Enter William 'Red' Whittaker, a robotics expert that has been testing a bot in a defunct coal mine near his home in Pennsylvania. His 4-wheeled Cave Crawler is still a prototype at this point but NASA Innovative Advanced Concepts (NIAC) is funding the project to turn it into a reality by 2015.