4 ms·
It's obviously a question of power and antenna gains, but a very important role is played by the encoding: Pioneer before, and Voyager after introduced concaten
by muxator 9y ago
It's obviously a question of power and antenna gains, but a very important role is played by the encoding: Pioneer before, and Voyager after introduced concatenated codes [0], which consist of a viterbi decoded convolutional code inside an outer Reed Solomon code.
Curiously, those codes are now superseded by other, more modern approaches, for example Turbo Codes [1] which are used not only in deep space probes, but also in cellular communications and other applications that we consider normal these days.
[0] https://en.m.wikipedia.org/wiki/Concatenated_error_correction_code https://en.m.wikipedia.org/wiki/Concatenated_error_correctio...
[1] https://en.m.wikipedia.org/wiki/Turbo_code https://en.m.wikipedia.org/wiki/Turbo_code
- botskonet 9y agoI read those links because I'm really curious but I clearly lack the prerequisite knowledge.
- anderspitman 9y agoI worked as an RF engineer for a few years and one of the senior engineers once told me a story about how they launched Voyager (I think it was Voyager) with a Viterbi encoder, even though we didn't have the ability to make a decoder at that time due to lacking the computing power. So they launched it knowing they would eventually have the technology, and of course they were right. No idea if that's true or not but I love the story.