Without new landers or rovers, it's helicopters or bust for NASA's Mars program

For the first time in more than 30 years, NASA has no firm plans to send any new landers or rovers to Mars. Instead, the agency's near-term focus at the red planet is on aerial drones, a pioneering mode of exploration that didn't seem realistic until a few years ago. The first real use of drones for science at Mars will come with the SkyFall mission, a fleet of three helicopters set for launch as soon as late 2028.