Spirits are running high among NASA engineers.
Mission managers say the check-ups they've run have found the Mars rover and its scientific instruments survived the long trip from Earth to the red planet.
So far, at least three of the craft's sensitive instruments have checked out ok.
Named after the roman god of war, Mars has been a battle with many failures. This time there has been a victory. The rover "Spirit" is on the surface and beaming back beautiful images.
NASA says that "Spirit" had a perfect landing and the rover will be able to collect many samples. Many hope that successful robotic landings will lead to missions with a more human touch in the future.
The Spirit's journey started last June and has covered over 300 million miles. In three weeks the probe "Opportunity" will land on the other side of Mars and perform the same mission.