eli5: What happens when a live digital video feed is being transmitted to earth from a spacecraft traveling away?

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For example, if I was on a rocket to mars and transmitting a video stream back to earth non-stop for the duration of the journey…

At the begining when I am leaving earth, the lag between me transmitting the video and earth recieving it would be basically nothing. But by the time I get to mars there is a delay of 3 minutes or whatever between send and recieve.

What happens to the video during the journey? Do some frames randomly drop? Does the video have to buffer constantly? Is there an incremental decrease in quality over time?

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18 Answers

Anonymous 0 Comments

Assuming you’re moving at a relatively constant speed relative to the earth, the information would essentially experience a Doppler effect.
The only effect this would have on the video is the “capture bitrate” on Earth, versus your “streaming bitrate”.
(As an example), if you were moving away at 1/1000th the speed of light, sending 1000 packets of information every second would allow the earth to capture 999 of them. None would be lost however, just more and more are “in transmission” at a time.
(Note: not actually sure of the proper math / formula).

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