All of these missions are exciting in their own right. But the selection has once again highlighted the limited amount of funding in planetary exploration, with scientists bemoaning the fact we can only do one of these missions, not all of them.
There is an abundance of worlds in our Solar System of huge interest. Mars, of course, has plenty of proponents and missions, with NASA keen to "follow the water" here in its search for life.
Then we have the icy moons Enceladus, Europa, and all, each with the tantalizing possibilities of oceans beneath their surface. Venus, meanwhile, has been devoid of a proper NASA mission since 1989, leaving some to wonder if we are losing our window to make use of prior expertise.
NASA can only do so much with its limited budget. But there are just so many interesting destinations to explore in the Solar System. That we only get a handful of missions each decade is a travesty – the places we don’t get to visit just cry out even more.
With Trump recently doubling down on returning humans to the Moon, and VP Pence repeatedly saying the US needs to lead in space again, planetary science runs the risk of being left by the wayside. And it would be to the detriment of all.
Venus, in our Sun’s habitable zone, may offer clues as to what exoplanets might feasibly support life, itself being inhospitable for reasons that are not clear. Enceladus may have the key ingredients for life beneath its surface. Further out, Neptune and Uranus – visited only once, fleetingly, by Voyager 2 – give us the chance to study fascinating ice giants.
CAESAR and Dragonfly both offer incredible scientific returns. The smart money would be on CAESAR to be selected, given that it uses tried-and-tested technology. Many will bemoan the places left untouched, though. The Solar System is crying out for us to explore it – if only we had the money.