Communication

Human Communication

There can be many forms of human communication. One is to keep in touch with family and friends via email. Phone and video links are also possible, but there is a short lag time between sending and receiving chunks of communication between parties. Another option would be to create a blog describing the lives and activities of a space explorer. This can of course include multimedia and text.

Present Licensing Situation

NASA missions to the Moon communicate back to Earth on by radio frequency (RF) in the X and L bands. These bands may not be used for commercial applications by law.

The Moon is legally considered part of the near-Earth environment. Only RF frequencies allocated for commercial uses on Earth can be used for commercial Earth-Moon communications. All available bands are currently allocated. None are allocated for commercial Earth-Moon communications. When a band becomes open, as one did recently, it sells for billions of dollars. A fledgling commercial Moon operation could not possibly bid in such a high-stakes auction.

Until this problem is solved, all lunar commercialization ideas are on hold.

Cis-Lunar Bandwidth

Various agencies are collaborating and competing to produce interplanetary communications networks. The Moon needs to be included as a node within the Interplanetary Internet.

Here is the web link to the Interplanetary Internet http://www.ipnsig.org/

Designing communications system across large distances involves calculating a "link budget". This is the relationship between power levels, size of antennas and data rates. Here is the Wikipedia page regarding Link Budgets: http://en.wikipedia.org/wiki/Link_budget

Optical Option

One option is to develop optical Earth-Moon communications. The transmitter is basically a laser attached to a small telescope. The receiver is a solid state sensor attached to a somewhat larger telescope. This equipment is considerably smaller than that used for comparable RF communications and has a far greater bandwidth.

One problem with optical communications systems is cloud penetration. This may be addressed by first: infrared frequencies penetrate the clouds best. Second, locations for the Earth stations must be in areas with a minimum amount of cloud cover such as the American Southwest. Third, a minimum of two, and preferably three, Earth stations must be visible from the Moon throughout the month.

These requirements suggest a system of optical stations around the world. Four or five Earth stations should do and they can be easily integrated with existing telephone facilities.

The lunar station will require two send/receive sets that can independently track the two best Earth sites at any time. They will have no cloud problem.