Water once flowed on Mars US space agency said on Saturday that Spaceship Curiosity used the drill at the end of its robotic arm to dig a tiny hole 1.6 centimeters across and 6.4 centimeters deep on the Martian surface. Further said the rover collected powder samples of crushed rock.; Rover since its landing in August of last year, Curiosity has found evidence that water once flowed on the planet Mars