At 1:28 PM Eastern Monday, NASA's MAVEN spacecraft blasted off on a mission to explore Mars' atmosphere.
The new robotic orbiter launched from Cape Canaveral Air Force Station in Florida on a trip of more than 440 million miles .
MAVEN - or the Mars Atmosphere and Volatile Evolution Mission - is set to reach Mars in September 2014.
Once it gets there, the orbiter will spend a year's Earth time looking for clues to better understand the planet's radical climate change from warm and wet to cold and dry.
NASA astronaut Mike Hopkins spoke from the International Space Station - before the launch.
(SOUNDBITE) NASA flight engineer Mike Hopkins SAYING:
"Like a lot of the research we are conducting on the International Space Station, understanding the Red Planet's atmosphere is essential to NASA's goal of safely sending humans there one day."
NASA says the mission has a pricetag of $671 million.
