June 28, 2007 — The rover Opportunity will begin a new round of studies for past water on Mars as it descends into a massive crater that managers hope will not become its final resting place.

"We can't guarantee we can come back out," said Alan Stern, NASA's associate administrator for science. "We know the rewards are worth the risk."

Opportunity has been exploring an equatorial region of Mars known as Meridiana Planum since it arrived 3.5 years ago. A twin rover, Spirit, is working on the other side of the planet at a site known as Gusev Crater.

Both rovers have found evidence of past water on Mars.

Opportunity's latest quarry has been a half-mile-wide impact crater known as Victoria Crater, located about four miles south of the rover's landing spot.