NASA will launch the 2020 Mars mission in 2020, and, besides carrying a new type of Mars Rover , it will carry a small helicopter specially designed to be able to fly on Mars. Since the Mars Atmosphere is different than on Earth, developing this helcopter is a challenge. The atmospheric pressure on Mars is the same as it is on 100,000 feet high on Earth. The highest a helicopter has ever flown on Earth is 40,000 feet. So they had to make some serious changes to any Earth flying helicopter.
"Yet the Mars Helicopter will be able to fly as high as about 15 feet above the Red Planet thanks to its two sets of rotor blades – each four feet long, tip-to-tip – spinning at 2,400 rotations per minute, which is about 10 times faster than an Earth helicopter." (NASA )
If NASA succeeds, it will be the first time we are able to explore another planet by air. We will be able to photograph and discover exponential more surface compared to the previous Mars mission.