CAPE CANAVERAL, Fla. — In our solar system family, Mars is Earth’s next-of-kin, the next-door relative that has captivated humans for eons. The attraction is sure to grow with Monday’s arrival of a NASA lander named InSight.

InSight should provide our best look yet at Mars’ deep interior, using a mechanical mole to tunnel 16 feet deep to measure internal heat, and a seismometer to register quakes, meteorite strikes and anything else that might start the Red Planet shaking.

Scientists consider Mars a tantalizing time capsule. It is less geologically active than the twice-as-big Earth and so retains much of its early history. By studying the preserved heart of Mars, InSight can teach us how our solar system’s rocky planets formed 41/2 billion years ago and why they turned out so different.

“Venus is hot enough to melt lead. Mercury has a sunbaked surface. Mars is pretty cold today. But Earth is a nice place to take a vacation, so we’d really like to know why one planet goes one way, another planet goes another way,” said InSight’s lead scientist Bruce Banerdt of NASA’s Jet Propulsion Laboratory in Pasadena, California.

Today’s Earthlings are lured to Mars for a variety of reasons.

Mars – “an incredible natural laboratory” – is reasonably easy to get to, and the U.S., at least, has a proven track record there, said Lori Glaze, NASA’s acting director of planetary science.

And, Mars may have once been flush with water and could have harbored life.

“Trying to understand how life is – or was – distributed across our solar system is one of the major questions that we have,” Glaze said.

“Are we alone? Were we alone sometime in the past?”

In two years, NASA will actually seek evidence of ancient microbial life on Mars – if, indeed, it’s there.

On Monday, the space agency announced Jezero Crater as the landing site for the Mars 2020 rover, which will gather samples and stash them for return to Earth in the early 2030s. The crater’s ancient lake and river system is brimming with diverse rocks, making it a potential hot spot for past life.

Michael Meyer, NASA’s lead scientist for Mars exploration, said the Martian surface is too cold and dry, with too much radiation bombardment, for life to currently exist.

Going to Mars is “a dream,” said the French Space Agency’s Philippe Laudet, project manager for InSight’s seismometer. “Everything is captivating.”

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