Dark side of the moon
The solar system began to form about… 4.6 billion years ago. Give or take a couple of million…
Our moon was potentially ‘habitable’ for about 500 million years after its formation… about 3.5 billion years ago. During its ‘brief’ tenure as a satellite capable of supporting life it had enough water to maintain an atmosphere (of about 1% of earths current atmosphere) which would have been enough for pools of water to form. The volcanic action also helped replenish the atmosphere.
Perhaps most importantly is that there is evidence to suggest that the Moon had a magnetic field which would have protected it from solar and cosmic radiation.
It is unlikely that life would have gotten past the single cell organism phase in that ‘brief’ window, but still, there was potential there.
Perhaps instead of a tidal locked hunk of rock we should consider the moon more like a giant microbial graveyard circling round the earth… a testament that life in the universe is harsh and unforgiving, a portent of things to come.