At about 9:06pm local time (1206am EST/0506 GMT) engineers received a signal that Opportunity had touched down on the Meridiani Planum, a smooth plain near Mars' equator on the other side of the Red Planet from its twin rover, Spirit.

"We are on Mars, everybody," Wayne Lee, the entry, descent and landing specialist, said after scientists received a signal from Opportunity when the airbag-encased space craft began
bouncing on the Mars surface. 

The lander shot through the Martian atmosphere in what appeared to be a flawless six-minute sequence, exactly like Spirit's landing about three weeks ago. 

About nine minutes after landing, there was evidence the spacecraft was still rolling gently, which was not unexpected because the plain is very flat.