Sentence:  Scientists say that while the public may think of the moon as a problem solved and a bit <WSD>retro</WSD> – the place astronauts visited a half-dozen times way back before Watergate and then abandoned with a giant "meh" from mankind – in fact, lunar studies is a vibrant enterprise that is yielding a wealth of surprises. 
Meaning of the word marked with <WSD> tags:  Of, or relating to, the past, past times, or the way things were.