The Mars rover "Curiosity" touched down on schedule Sunday night, and immediately began beaming back images of the Martian surface.
NASA's website carried the entire landing live via streaming video, as dozens of engineers and technicians erupted into jubilant celebration.
There were tears among the NASA employees watching, as tension from the mission turned into elation.
There was some fear that the mission might not make it past the technically daunting landing, one like no other that NASA has attempted.
Scientists wanted to place the rover in a spot that looked promising in their ongoing search for evidence of prior life on the red planet.
Doing so meant a multi-stage descent fraught with potential problems.
A description of the landing from NASA.gov gives us some idea of the complexity involved:
"NASA's Curiosity rover has landed on Mars! Its descent-stage retrorockets fired, guiding it to the surface.
Nylon cords lowered the rover to the ground in the "sky crane" maneuver. When the spacecraft sensed touchdown, the connecting cords were severed, and the descent stage flew out of the way.
The time of day at the landing site is mid-afternoon -- about 3 p.m. local Mars time at Gale Crater. The time at JPL's mission control is about 10:31 p.m. Aug. 5 PDT (early morning EDT). "
An image of the planet's surface was broadcast just minutes after landing.
Assuming that Curiosity has survived it's landing with all systems intact, scientist can expect to mine valuable data from the rover for the next 2+ years.