Mars

The job posting has elicited headlines about how the space agency is seeking a person to defend Earth from aliens. But it's really more about microorganisms than little green men.

Scientists say the rocks lend weight to a theory that life on Earth originated, as Darwin wrote, "in some warm little pond" on land, suggesting we should look for it in similar environments on Mars.

Starting Thursday, six people will spend eight months in a dome on Mauna Loa volcano to study what living on Mars might be like. The mission is co-sponsored by the University of Hawaii and NASA.

NASA engineers are trying to figure out why a part of the rover's robotic arm keeps stalling just as it's about to drill into Martian rock.

Instead of drifting gently onto Mars' surface, the Schiaparelli Mars lander hit the planet hard — and possibly exploded, the European Space Agency says.

As scientists try to figure out what happened to the Schiaparelli lander, which may have crash-landed, a craft known as the Trace Gas Orbiter is orbiting the red planet in search of signs of life.

The Schiaparelli probe was supposed to make a six-minute descent through the red planet's atmosphere and make a controlled landing on the surface. Scientists are waiting for word.

The Schiaparelli lander detached from its mothership, the Trace Gas Orbiter, on Sunday. It's expected to make a controlled landing on the Red Planet on Wednesday.

In an op-ed for CNN, the president wrote that he hopes to one day look at the night sky with his grandchildren and tell them that humans are living on Mars.