Mars is about to get its first US visitor and it's a 3-legged, 1-armed geologist

Washington, Nov 22: Mars is about to get its first U.S. visitor in years: a three-legged, one-armed geologist to dig deep and listen for quakes.

NASA's InSight makes its grand entrance through the rose-tinted Martian skies on Monday, after a six-month, 300 million-mile (480 million-kilometer) journey. It will be the first American spacecraft to land since the Curiosity rover in 2012 and the first dedicated to exploring underground.

It will be the first American spacecraft to land since the Curiosity rover in 2012 and the first dedicated to exploring underground.

One experiment will attempt to penetrate 16 feet (5 metres) into Mars, using a self-hammering nail with heat sensors to gauge the planet's internal temperature. That would shatter the out-of-this-world depth record of 8 feet (2 1/2 meters) drilled by the Apollo moonwalkers nearly a half-century ago for lunar heat measurements.

The astronauts also left behind instruments to measure moonquakes. InSight carries the first seismometers to monitor for marsquakes - if they exist. Yet another experiment will calculate Mars' wobble, providing clues about the planet's core.