The 790-pound InSight lander is the first spaceship dedicated to digging deep below the surface of the red planet. It has a robotic arm that is capable of digging up to 16 feet underground.
The probe will also measure temblors on the planet, known as "marsquakes."
The May 5 launch window opens at 4:05 a.m. PT. Afterward, the InSight will travel for six months before arriving at its destination. If all goes as planned, it will land on Nov. 26.
Five other NASA spacecraft are currently operating on or above Mars.