Robert Clark wrote:
I had been thinking about methods of high data rate transmission in
regards to getting *video* transmissions from Mars orbiter missions. I
was irritated by the spotty coverage of the Mars surface at the best
resolutions so I wanted to send real-time *continuous* imaging back to
Earth receiving stations at the highest imaging resolutions. This
would require very high transmission rates, much higher than what is
currently used.
The idea would be to use light transmissions but only of the on-off
variety. You would use a large surface, many meters across, capable of


Bob,
You might not want to cross-post to 5 groups.

1) what spotty coverage? I doubt any gaps are due to the lack of data
bandwidth from Mars to Earth, except when MRO goes behind Mars, or
similar line of sight interruptions. There's a non-zero cost to running
DSN antennas, too. In any case, getting sufficient bandwidth in a pipe
to earth isn't a matter of technology, it's a matter of money.
2) Optical comm with very high bandwidths is a subject of research and
development at NASA (at JPL) and the USAF (at Lincoln Labs). Lots of
interesting ideas for receivers on the Earth, etc. Doesn't take a huge
telescope or high powers at either end. They use, IIRC, a form of pulse
position modulation.


There was a special issue of IEEE Proceedings October 2007 (Special
issue on Technical Advances in Deep-Space Communications and Tracking)
that discusses a lot of this stuff. (including optical) Read it and
learn, rather than just looking at press releases and formulating ideas
from that.