Scientists have discovered water on the sunlit surface of the moon for the first time, but does it matter? The moon is back in vogue in terms of space exploration - the US says it will put astronauts back on the lunar surface by 2024. It's supposed to be the precursor to a manned mission to Mars. Stephen Sackur speaks to Jacob Bleacher, chief exploration scientist at Nasa. In this time of pandemic and climate change here on Earth, is space exploration a potential lifeline or a massive vanity project? Show less