A NASA spacecraft has entered into orbit around Mars, after a 10-month, 700 million-kilometer journey.
The U.S. space agency said the "Maven" (Mars Atmosphere and Volatile Evolution) spacecraft fired its braking rockets early on September 22 as it flew over the planet's north pole.
Flight controllers will spend the next six weeks adjusting the craft's altitude and checking its science instruments.
Then "Maven" will start probing the Martian upper atmosphere.
Scientists believe the Martian atmosphere holds clues as to how Earth's neighbor went from being warm and wet billions of years ago to cold and dry.
That early moist world may have harbored microbial life.