an interesting article on one of the few scientific instruments (a geochronometer to date rocks) that has so far resisted being miniaturized enough to be flown on a planetary lander
Planetary science: The time machine

Great article, very detailed!
Hope it manages to get on board an actual mission!

This is the best idea ever.

This is very promising instrument. Almost all data about age of planetary surfaces are model dependent (only exception is Moon and only for few surface features) and only way to accurately date any surface is sample return mission (it's very expensive) or lander with such instrument. Fortunately more teams are working on such instruments (from USA, Slovakia, Japan and possibly other countries) so we can expect some interesting data in near future.