Lunar Communications Using Relays

Employing lunar orbiting relays for Earth-Moon communications offers several advantages that include the ability to communicate from the far side of the Moon, improved link conditions for the near-side communications and providing lunar-surface-to-lunar-surface connectivity. Due to the recent surge of interest to explore the Moon robotically and possibly develop human colonies, industry has responded by making plans to provide communication relay services for the Moon. Similarly, NASA is also investing in lunar surface radios that can be readily obtained by future users for lunar relay communications. The proposed relay arrangements vary from single-satellite networks to multi-satellite infrastructures. This paper will review the proposed relay systems and will discuss a user communication terminal that is currently being developed via NASA support. A discussion of the target capabilities that are presently being developed will be provided. Moreover, the likely technical approaches that will be utilized to enable lunar communications will be addressed. These will include physical layer technologies as well as algorithms and protocols that may be adopted. A brief discussion of standards will also be offered.