Published 11:21 IST, February 17th 2021

NASA is attempting its toughest Martian touchdown yet. The Mars 2020 Perseverance Rover is headed Thursday for a compact 5-mile-by-4-mile (8-kilometer-by-6.4-kilometer) patch on the edge of an ancient river delta on Mars. It's filled with cliffs, pits, sand dunes and fields of rocks, any of which could doom the $3 billion mission.