PASADENA, the United States, Jan. 24 (Xinhuanet) -- As NASA struggled to revive its ailing Spirit Mars rover, the agency's second spacecraft Opportunity landed safely on the Red Planet Saturday night to search for signs of water.

    "We are on Mars, everybody," Wayne Lee, the entry, descent and landing specialist, shouted as fellow scientists at NASA's Jet Propulsion Laboratory (JPL) burst into wild applause.

    During its landing process, the Opportunity slowed first by a parachute, then retrorockets. Finally, at a height of about 30 feet, the rover, encased in a cocoon of air bags, bounced and rolled for half a mile before coming to a stop.

    NASA's ground controllers did little on Saturday night as all of the rover's actions are programmed in its onboard memory.

    NASA said it could take up to 22 hours to hear from Opportunity after it landed.

    The Opportunity's landing area is known as Meridiani Planum, which has been found to contain the detectable mineral signatures for coarse grained gray hematite -- a type of iron oxide mineral.

    On Earth, gray hematite usually forms in association with liquid water. Some environmental conditions that can produce gray hematite could be quite hospitable to life.

    Like its twin Spirit on the other side of Mars, Opportunity will use a rock abrasion tool and two spectrometers attached to the rover's arm to resolve how Martian environment produced the hematite at Meridiani Planum.

    "I think we're going to see some very interesting terrain," said Steve Squyres, principal investigator for the rover program and a space scientist from Cornell University. Enditem