THE second of NASA’s two Mars rovers, Opportunity, landed without a hitch yesterday.

Its twin sister Spirit, which landed on the Red Planet three weeks ago, was beset with communication problems last week, with theflow of pictures and scientific data ceasing last Wednesday. Over the weekend, scientists isolated the problem to the rover’s memory software and are now hopeful it can be fixed.

Opportunity sent information right from the beginning of its landing on the opposite side of the planet to Spirit. One of the primary purposes of the Mars probe is to determine if the planet had once been capable of supporting life.

The unmanned six-wheeled rover landed shortly after 4pm AEST yesterday on the Meridiani Planum, one of the flattest parts of Mars. Scientists believe it is made up of a mineral known as gray hematite, which typically forms in marine or volcanic environments rich in water.

Opportunity rolled for up to 10 minutes after hitting the planet’s surface, before coming to rest about 24km from its target. Overnight it was expected to use motors to retract the impact cushions before opening up like a petal to reveal the rover inside. Solar panels will then be deployed and it will begin its work within hours.