NASA mission aims to determine whether planet was once habitable
NASA’s Opportunity rover has finally reached its most important target, a massive 20-km crater called Endeavour, after three years of traversing the planet’s surface, New Scientist reports. The crater rim is littered with rocks that are thought to be over 3.5 billion years old, dating from the wettest period of the planet’s history. Opportunity and its sister rover, Spirit, previously looked at rocks immersed in acidic and salty water, but this crater seems to have held water that could potentially have supported life. Opportunity is looking for clues as to whether Mars, now freeze-dried and barren, was once habitable.