» RELATED: Anxiety abounds at NASA as Mars landing day arrives

"We've studied Mars from orbit and from the surface since 1965, learning about its weather, atmosphere, geology and surface chemistry," Lori Glaze, acting director of the Planetary Science Division in NASA's Science Mission Directorate, said in an agency statement Sunday. "Now we finally will explore inside Mars and deepen our understanding of our terrestrial neighbor as NASA prepares to send human explorers deeper into the solar system."

Everyone involved in the $1 billion international mission is understandably nervous. They say they've had trouble sleeping, and their stomachs are churning. It's risky business to descend through the Martian atmosphere and land, even for the U.S., the only country to pull it off. It would be NASA's eighth landing on Mars.



Before InSight makes its big landing, it will have to "survive a harrowing descent to the ground." According to The Verge, this descent involves a multi-step routine in which the spacecraft "will free-fall through the atmosphere using a heat shield for protection." The air surrounding InSight is expected to heat up to temperatures of 2,700 degrees Fahrenheit, making it even more difficult to land on the surface of the Red Planet.

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To ensure a safe landing, InSight will have to “deploy a supersonic parachute” and “ignite onboard thrusters” to slow from a speed of more than 12,000 per hour to 5 miles per hour and gently lower itself to the ground, according to the Verge. This routine will last between six and seven minutes.

Engineers with NASA’s Jet Propulsion Laboratory spent much of their Thanksgiving weekend (and months prior) preparing for this complicated multi-step landing, making adjustments based on the latest weather reports.

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“It's taken more than a decade to bring InSight from a concept to a spacecraft approaching Mars — and even longer since I was first inspired to try to undertake this kind of mission,” said Bruce Banerdt, InSight's principal investigator. “But even after landing, we'll need to be patient for the science to begin.”

In fact, according to Banerdt, it will take between two to three months for the spacecraft’s robotic arm to even set the mission’s instruments on the planet’s surface. In the meantime, JPL engineers will continue to monitor the environment and take photographs of the terrain.

The Associated Press contributed to the report.