More than half a century after Neil Armstrong took mankind’s giant leap on the moon, another space race is heating up. This time, the promising new frontier for Earthlings is Mars, the planet next door.

A spate of robotic missions to the red planet, including NASA’s Perseverance rover this year and China’s Zhurong this month, have led to the inevitable question: When can humans follow? Unmanned missions over the decades have beamed a trove of information, including the presence of water ice on Mars, fueling expectations a human landing is possible. But how soon? And, are we ready?

NASA wants to send astronauts to Mars, perhaps at some point in the 2030s. The United Arab Emirates — which now has a spacecraft orbiting the planet — is promoting a 100-year plan to create a colony there. While China has said sending humans to Mars is its long-term goal, those eager for a taste of Martian life can visit a simulation site in the Gobi desert for now.