Talk about a tough road to climb. On 24 June, mission scientists endorsed two landing sites for NASA’s next Mars rover from a shortlist of four. One of the two would see Curiosity tackle a mound of rocks nearly as high as mount Kilimanjaro. Where to land the $2.5 billion robot, due to blast off in November, has been debatedMovie Camera for years. NASA will now mull over the mission scientists’ recommendations but is not obliged to follow either of them.