NASA on Thursday launched the Mars 2020 Perseverance rover on a United Launch Alliance Atlas V rocket from Space Launch Complex 41 at Cape Canaveral Air Force Station in Florida.
"We have LIFTOFF to Mars! The @ulalaunch Atlas V takes flight with our @NASAPersevererover. The #CountdownToMars continues as Perseverance begins her 7-month journey to the Red Planet," NASA said in a tweet.
The rover will land in Mars' Jezero Crater on February 18, 2021.
The mission -- designed to better understand the geology and climate of Mars and seek signs of ancient life on the Red Planet -- will use the robotic scientist, which weighs just under 1,043 kgs and is the size of a small car, to collect and store a set of rock and soil samples that could be returned to Earth by future Mars sample return missions.
Perseverance will also ferry a separate technology experiment to the surface of Mars -- a helicopter named Ingenuity, the first aircraft to fly in a controlled way on another planet.
It also will test new technologies to benefit future robotic and human exploration of Mars.
NASA's Mars 2020 Perseverance is part of America's larger Moon to Mars exploration approach that includes missions to the Moon as a way to prepare for human exploration of the Red Planet.
NASA said its Perseverance rover builds on the lessons of other Mars rovers.
The US space agency's first rover on Mars was modest: Sojourner, the size of a microwave oven, demonstrated in 1997 that a robot could rove on the Red Planet.
NASA's next Mars rovers, Spirit and Opportunity, were each the size of a golf cart. After landing in 2004, they discovered evidence that the planet once hosted running water before becoming a frozen desert.
The car-sized Curiosity rover landed in 2012. Curiosity discovered that its landing site, Gale Crater, hosted a lake billions of years ago and an environment that could have supported microbial life.
Perseverance aims to take the next step, seeking, as a primary goal, to answer one of the key questions of astrobiology: Are there potential signs of past microbial life, or biosignatures on Mars?