Mars has a new visitor from Earth. MAVEN, the Mars Atmosphere and Volatile Evolution spacecraft, entered into orbit around the Red Planet on September 21 and is now preparing for its primary mission — to study the planet's upper atmosphere. The goal of the mission is to understand how the climate of Mars has changed over time. "It also will better inform a future mission to send humans to the Red Planet in the 2030s,” NASA Administrator Charles Bolden said in a statement. MAVEN is slated to study the Martian atmosphere for at least one Earth year.