PASADENA, California: The countdown to Mars is on.
Curiosity is on course to hit the top of the Martian atmosphere Sunday night for what NASA hopes would be a soft landing.
NASA is bracing for the "seven minutes of terror" plunge. Before Curiosity dives through, mission controllers will pass out "lucky peanuts" as they have done for past missions.
Touchdown was set for 10:31 p.m. PDT (0331 GMT).
Since there could be spotty communication during the descent to the surface, confirmation could be immediate or it could take hours or even days to know the outcome.
Curiosity is on a mission to study Mars' environment to determine whether conditions could have supported microbial life.
The $2.5 billion project is the most sophisticated and expensive yet to Mars.