So I understand what was said here and here, but not everything is clear to me.

If they were able to transmit from the Moon, then why in 1985 were we not able to have an audio/video song performed by Mick Jagger in Philadelphia and David Bowie in London.

  • $\begingroup$ I have cleaned up the question and reopened because I do think it is a worthwhile question, though I fear the answer may have more to do with broadcast performances and less to do with space communications. It may be more appropriate at another site like Video Production. $\endgroup$
    – called2voyage
    Nov 3, 2015 at 15:28
  • $\begingroup$ On the other hand, it may be useful for some to have a comparison between space broadcasts and other more familiar broadcasts, so I'll let the community decide. $\endgroup$
    – called2voyage
    Nov 3, 2015 at 15:29

1 Answer 1


For two people to sing together, they have to be synchronized. This is difficult when sending a signal from Philadelphia to London takes at least 0.2 seconds one way (*).
If you have access to an audio delay effect you can try this for yourself.

For the live broadcast from the Moon, the delay was even longer, but the people on the Moon weren't trying to sing together with people in Mission Control.
When you listen to the unedited recordings from Moon broadcasts, you'll notice long delays when the astronauts have to respond to a question from mission control.

*: it's 0.2 seconds when the signal is sent via a geostationary satellite. If you used a cable link the delay would be shorter, but broadcast-quality cable links were in short supply in 1985.


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