When a sim watch clouds or stargazes without a telescope there is a 1% chance of a satellite death. This is checked only at the beginning of the action, not every cycle. If the death check succeeds, the satellite will fall after 5-24 animation cycles. If the sim quits before this time, the satellite will not fall.

Since satellite chance is checked only at the beginning, stargazing for longer doesn't increase death chance. If you wanted to try for satellite death you have to watch clouds/stargaze for 24 animation cycles (I don't know how long that is game time but there is a thought balloon every 3 cycles so 8 thought balloons will do it), cancel, and then do it again. Repeat until dead or bored.