Lasers Key To Interplanetary Comms

[Schneibster]

Medium and high frequency radio have worked well for NASA for many years, while spacecraft remained simple and easily controlled, and possessed of only a few instruments requiring little bandwidth to send their infrequent messages and occasional data dumps. Now, however, spacecraft are about to become very sophisticated, and capable of generating a really astonishing amount of data that must be accurately transmitted from, say, Jupiter, to, say, a geosynchronous Earth orbiting deep space communications satellite. Even microwave radio is not a wide enough channel any more.

NASA is therefore experimenting with laser communications, and has already established a record bandwidth channel to the Moon, if I read properly some 688Mbit. You can do nothing, of course, about the delay, but that's nothing new; radio has the same problem. But the advantage of lasers is their coherence; and now that we can generate them in solid state devices that won't wear out, doubtless there are several steps in bandwidth yet to come.

Good if short article: http://www.space.com/23350-laser-space- ... ology.html

[choff]

There was an article where SETI was looking for laser signals between star systems.

[Schneibster]

There was an article where SETI was looking for laser signals between star systems.

It might scatter off the interstellar medium enough to make a detectable side lobe.