The Columbus was an American spaceship which used a fusion engine to achieve constant acceleration. It was the second such ship built by the United States Air and Space Force and featured a number of improvements over the first, the Lewis and Clark. This was possible in part because the ship was built openly and from scratch, and not secretly converted from an orbital space station. The ship also featured a larger crew complement than the Lewis and Clark as well as a higher female-to-male ratio. It was launched in 1966 on a mission to the asteroid belt.