NASA's Phoenix spacecraft has successfully landed near Mars' north pole for a 90-day digging mission. Mission control at NASA's Jet Propulsion Laboratory celebrated after the Phoenix Mars Lander signaled back that it had survived Sunday's fiery entry. Phoenix will be the first spacecraft to study the Martian arctic plains. Unlike NASA's mobile twin rovers, the lander will stay in one spot. It will use its robotic arm to dig into the permafrost to determine if the polar environment has the ingredients needed for life to emerge.