A NASA spacecraft is aiming for an August landing on Mars. The one-ton rover nicknamed Curiosity is poised to fire its thrusters Wednesday to put itself on course. The maneuver is expected to last nearly three hours and will be tracked by deep space antennas. Engineers have several more chances over the next several months to fine-tune Curiosity's flight path before touchdown inside a crater near the Martian equator. The goal of the $2.5 billion mission is to see whether Mars, now cold and barren, might have been hospitable for microbial life, according to a report of the Associated Press.
