Monday, August 27, 2012

Alexander Graham Bell to NASA (or NASA and the incredible Laser Communications Relay Demonstration mission)

Current communications are done through Radio Waves. Basically we convert sound waves into their electrical signal equivalents. These electrical signals are used to modulate either the frequency or amplitude of a "carrier" radio wave. These signals are then picked up by your antennae on your radio receiver. Of course you dial in to particular frequencies and this differentiates which signal you receive. Also now we have cell phones and there are not only the conversations but wireless data such as is sent from the numerous smartphones simply uses the 2.4 Ghz range of the spectrum. So what we have is a crowded bandwidth with information at every end of the spectrum that includes the communication bursts and texts and tweets and internet searches of 314,254,458 in the US alone. And some of those people have multiple devices crowding the airwaves at the same time.

So why am I telling you all this? So you can understand one of the reasons NASA has a project for a new form of communications in space.

Consider the difficulties of space communications also the large packets of information that when they enter the earth’s atmosphere then need to compete to get fully received. Some of the communications are mission critical or filled with a lot of data and have traveled a long way to get garbled at the last minute.

So the format of communications that NASA is testing in this long duration experiment The wavelength of the laser light is much shorter than radio waves and is not spread out as much as it travels through space. What NASA hopes this new technology will deliver is video and high resolution measurements from all across the solar system. When trying to understand this concept best to dial it back. Think about the communications employed for phone communications that send signals instead of down a copper wire as a laser beam down a glass tubing. Using complex modulators to shape the laser pulses that are sent through fiber optic cables. Now take this form of communications and amplify it!

Obviously the sort of laser utilized in fiber optic cables and the kind that NASA is dreaming up besides being in different areas of the spectrum, NASA’s is capable of a lot more – distance, data rates, collection, etc. But you get the idea.

I have no idea whether this will be a viable format or not, but I think it is one worth exploring.

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