Pasadena (California): NASA's Opportunity rover today (Jan 25, 2004) successfully landed on Mars, arriving on the Red Planet exactly three weeks after its identical twin set down.

"We're on Mars, everybody,'' mission scientist Wayne Lee declared as fellow members monitoring the landing at NASA's Jet Propulsion Laboratory burst into wild applause.

The unmanned, six-wheeled rover landed at 10:35 hours (IST) today in Meridiani Planum, NASA said. The smooth, flat plain lies 10,620 kilometers and halfway around the planet from where its twin, Spirit, set down on Jan 3.

Together, the twin rovers make up a single $ 820 million mission to determine if Mars ever was a wetter world capable of sustaining life.

Since arriving, Spirit has developed serious problems, cutting off what had been a steady flow of pictures and other scientific data.