Unlike many other spacecraft, the Cislunar Explorers do not require extremely accurate knowledge of their positions relative to the Earth in order to achieve total mission success. While Apollo and nearly all other lunar missions required an extremely precise orbit, the Cislunar Explorers must “simply” get any lunar orbit and maintain it for as long as possible. These unique mission requirements allow for a very unique method for navigation. A brief summary follows; see our published papers on the subject for more details.
Rather than using Earth-based ranging facilities for navigation (as nearly all other deep-space missions require), the Cislunar Explorers will navigate completely autonomously. After being deployed from the launch vehicle, the Cislunar Explorers will each turn on their commercial-off-the-shelf cameras that enable them to view their surroundings. The view will be dominated by three things: the Earth, the Moon, and the distant Sun. By studying the sizes of each of these objects and their locations relative to one another, the Cislunar Explorers will deduce their locations for themselves. They will not be able to do so with the same level of accuracy that would be expected from Earth-based ranging facilities, but they will do so well enough to navigate themselves to lunar orbit. This technology could enable more deep-space and low-cost cubesat missions.