Curiosity, the largest and most advanced spacecraft ever sent to another planet, stuck its extraordinary landing in triumphant and flawless fashion, and is poised to begin its pioneering, two-year hunt for the building blocks of life — signs that Earth’s creatures may not be not alone in the universe.

NASA’s $2.5-billion mission involved the work of more than 5,000 people from 37 states, some of whom had labored for 10 years to hear the two words that Al Chen, a Jet Propulsion Laboratory engineer, said inside mission control at 10:32 p.m.: “Touchdown confirmed.” Chen reported that Curiosity was in a “nice flat place,” and as icing on the cake, the spacecraft sent home thumbnail photographs of itself.