The MAVEN spacecraft is an exciting new unmanned Mars mission designed specifically to study the upper atmosphere of Mars. By studying how Mars' atmosphere is lost to space today, MAVEN will allow us to answer some important questions about the history of the red planet. How did it lose its atmosphere and surface water? How did its climate change? With data from MAVEN, we'll be able to determine how Mars' climate has changed over time, and how Mars transformed from a planet that possibly had a thicker atmosphere and liquid water to the barren landscape we see today.