Nasa will attempt to land its Curiosity rover on Mars late Sunday night in an attempt to find out whether or not the planet may have contained microbial life. The mission is risky—two-thirds of all exploration project attempts have failed due to Mars' difficult and dangerous atmosphere. If Curiosity lands without incident it will spend 98 weeks searching Martian terrain for signs of current or past life-supporting environments. "It will be really exciting; it always is. It's electrifying but it's tense," Doug McCuistion, the director of Nasa's Mars program said.