The U.S. space agency says the Mars robotic vehicle Spiritis ready to begin exploring the planet's surface.

NASA officials say Spiritis now standing fully erect, at 145 centimeters, and has extended its six legs, indicating it is ready to leave the landing platfform.

Mission engineers say deflated airbags that cushioned the vehicle's fall to the Martian surface are partially blocking the exit ramp. They are considering rotating the rover and driving it off the side of the lander - a drop of about 40 centimeters - rather than risk getting its solar panels caught on the airbags.

The planetary explorer landed on Mars a week ago. NASA says the rover vehicle could start moving about the surface of Mars as early as this Tuesday, two days later than originally planned.

Spiritis the one of two identical robot planetary explorers called "rovers" designed to roam the surface of Mars for 90 days, searching for evidence of water, which is a key element in supporting life.

NASA scientists believe sediments in Mars' rocks could point to a time long ago when Mars may have been warmer and capable of supporting life.

The second rover, Opportunity, is scheduled to land on the opposite side of Mars in about three weeks.