LA CANADA FLINTRIDGE, Calif. -- On Sunday, about a dozen engineers and scientists gathered in the mission control room at NASA's Jet Propulsion Laboratory. They listened intently through headsets while training their eyes on a curving wall of monitors to follow the progress of the InSight spacecraft as it made its final approach to Mars.
Had it received their message through 90 million miles of cosmic nothingness?
It had. Just before 2 p.m., InSight fired its thrusters and banked a hair to the southwest.
It would be a few more hours until the members of the InSight team would know whether their maneuver had worked as planned. Even so, the group gathered in La Canada Flintridge breathed a collective sigh of relief.
"We are going to hit Mars, no matter what," said JPL's Bruce Banerdt, the principal investigator for the InSight mission.
But that's not the goal. Banerdt's team had been tweaking the spacecraft's trajectory throughout its winding, 300-million-mile game of interplanetary tag in hopes of guiding InSight to a carefully selected landing spot.
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"It's sort of like curling," he said. "The stone's moving on the ice, and we are sweeping at this point."
If the team nudges InSight just right, the lander will touch down around noon Pacific time Monday on Elysium Planitia, a vast, featureless expanse of ancient lava a few hundred miles north of where the Curiosity rover landed in 2012. There, it will do something no previous mission has managed: Peer inside the red planet.
Armed with an arsenal of specialized instruments, InSight will take Mars' temperature, monitor its seismic activity and investigate the nature of its core. Scientists hope the results will not only answer their questions about Mars, but about how planets in general work -- how they form and evolve over time, and how deep geologic processes determine whether the surface of a planet might be habitable.
"That's what we need to be able to extrapolate from Mars to exoplanets," said geophysicist Suzanne Smrekar, the deputy principal investigator for the mission.