<snip> My focus has been on the "data burst" in the UP sound 5 seconds before the globe image appears.
Problem is there's no easy way that I can find to determine the coding type / rate, and no commonly available 'universal' decoder software, so my conclusion is that it is a dead end as it's "too difficult", or more likely now given the picture it may just be noise there after all...
Further to the above, I did find some old software (that needed venerable WinXP to run) that would autodetect digital modulation, but I still had no joy. It saw the same two peaks that I did by eye. But when the software was trying to determine the baud / bit rate the result was not consistent, so making it even more likely than before there's only noise there. I manually tried a number of baud rates, and produced some 'output' but it was all random rubbish. No "WE'RE HIDING BEHIND MEROPE 6" message :-( More complexity is added when you needed to choose the character set - 7 bit or 8 bit ASCII, or Baudot etc. making it again feel too complex to be correct. I'm not sure our aliens know ASCII...
So this is just to add more negative evidence when looking at part of the UP signal looking for data to decode.
We know we have community friends in JPL, and at the BBC. Do we have other friends at other 'acronym' organisations like the NSA or GCHQ?