Laser Communications in Outer Space

[bodykey]

I just saw an article regarding NASA's Lunar Probe that will use lasers to communicate high resolution images and data from the Earth to the probe for faster comms.

My question is...in Outer Space with no atmospheric influence, at what distance would laser communications like this remain fully accurate (no loss of data)?

 

[mfb]

There is no "fully accurate", but you can reduce the risk to something like "on average 1 bit per 1 million years of data transmission", where you don't care about the hypothetical probability of this any more.
Error-correcting codes play an important role there.
The distance depends on the laser quality, power, wavelength, receiver telescope quality, data rate and many other factors.

 

[Chronos]

We have been bouncing lasers off the moon for over 40 years now [re: Lunar Laser Ranging Experiment]. The data quality is sufficient for incredibly precise measurements.

 

[bodykey]

So it would be safe to say that several bursts of lasers containing quantum information could be successfully transmitted without much of a flaw over say a 10 AU distance and received on the other end by another satellite?

:)

 

[mfb]

What exactly do you mean with "quantum information"? Do you want to share entangled photon pairs? That will lead to a very low efficiency for reasonable designs.
Just sending classical data is way easier, as you can send many photons, it does not matter if 99.999% (or more) are lost if you have enough of them.

 

[bodykey]

I just mean information, similar to the way that fiber optics send information along fiber cables. In pulses that are represented as zero's and one's.

 

[mfb]

That is not quantum information.
Transmitting data over a distance of 10 AU is possible, the data rate depends on sender and receiver.

 

[bodykey]

I suppose my more core question is, what is the limit of such communication? If 10 AU is possible, what about 100 AU, or 1,000 AU?

 

[mfb]

The limit is the data rate.
You can transmit data to other planetary systems, light years away (where 1 light year is ~63 000 AU). You just won't achieve the same data rate as in the communication with a satellite orbiting earth.

 

[bodykey]

Ok, gotcha. Thanks :)