NASA's Perseverance rover is moving toward a new target on Mars called 'Krokodillen,' located on the lower slope of Jezero Crater's rim. Scientists expect this area to offer up some of the oldest rocks on the Red Planet — material that predates the lake system that once filled Jezero and potentially records conditions from Mars's earliest geological history. The significance is stratigraphic. Jezero Crater was chosen as Perseverance's landing site because it preserves evidence of an ancient river delta — sedimentary deposits from a time when water flowed into and filled the crater. But the crater rim is older than the lake. The rocks exposed on the rim's lower slopes predate the delta sediments Perseverance has already studied, meaning they formed under earlier — and potentially very different — conditions. Reaching Krokodillen is reaching backward in time. Perseverance will take a core sample — 'take a bite' in NASA's phrasing — using the drill and sample-caching system that has been the rover's primary tool throughout the mission. These cached samples are the ones earmarked for eventual return to Earth as part of the Mars Sample Return programme, though that mission's timeline and architecture remain politically and technically uncertain. Every sample Perseverance collects is a bet that someone will eventually come get it. The naming convention is worth noting. Perseverance's science team has been systematically naming features using geographic and cultural references, and 'Krokodillen' follows this pattern. The names are functional — they give the team a shared vocabulary for discussing specific locations during daily planning — but they also accumulate into a kind of cultural cartography, mapping human language onto alien terrain. What makes this particular target compelling is the age question. Mars's geological record is poorly constrained compared to Earth's. We have relative ages from crater counting and stratigraphic relationships, but absolute ages for most Martian surfaces remain uncertain by hundreds of millions of years. A returned sample from Jezero's rim could provide radiometric dating that anchors the Martian timescale in a way no orbital measurement or rover instrument can. This is the deep-time payoff: not just knowing what happened on early Mars, but when. Perseverance is now well into its extended mission, operating on the crater rim after spending its primary mission on the crater floor and delta. The rover's mechanical and scientific systems continue to perform. The fact that it can still drill, cache, and traverse complex terrain years into the mission is a quiet engineering achievement that tends to get lost beneath the headline science — but it's the enabling condition for everything else.
