New York: NASA currently has two cars roaming Mars — the Opportunity and Curiosity rovers. But the next one it will send there will carry a vehicle with a new approach for planetary exploration: a helicopter.

The space agency announced the decision on Friday to add a small helicopter — about 1.8 kilos with a fuselage the size of a softball and blades that span just over a metre, tip to tip — to its Mars 2020 mission, which is to launch in July 2020 and arrive at Mars the following February.

"We're very excited about this and the potential it has for opening up a whole new paradigm for how to explore Mars," said David Lavery, the program executive for solar system exploration at NASA headquarters.

He likened it to Sojourner, the first Mars rover, which was about the size of a microwave oven and trundled around in 1997. "That said, 'Hey, mobile exploration on another planet is not only possible, but adds a lot of value to how you do things,'" Lavery said.

For its trip to Mars, the helicopter will be packed on the underside of the rover. After the rover lands, the helicopter will be placed on the ground. The rover will then drive 50 to 100 metres away — close enough to stay in radio contact, far enough to not be endangered by any mishaps.