Today, I read this exiting news, that NASA would be sending a helicopter to Mars along with with its Mars rover in 2020. This is exiting because if successful, we would be able to see aerial footage and birds-eye view of the planet Mars. We already have seen quite a few photos from Mars rovers, but all of them were taken on the surface of Mars. Another benefit is that the helicopter would be able to take photos/videos of regions on Mars, which cannot be reached by the Mars rover.
Due to the very thin atmosphere of Mars, which is only one percent that of the Earth, this helicopter will have twin blades that are going to whirl at a whopping speed of 3000 rpm, which is 10 times the rate of helicopters used on Earth. On Earth, you reach that much thin atmosphere at about 30 km above the sea level, while the altitude record for a helicopter on Earth is only 12 km.
Note that it takes several minutes for signals to reach Earth from Mars and vice versa. So flying this helicopter with a joystick in real time would be impossible. Instead commands would be given to it, so that it can fly a mission on its own.