Mars is about to get another visitor this weekend, in the form of NASA's MAVEN (Mars Atmosphere and Volatile Evolution) spacecraft. Unlike Mars rovers Opportunity and Curiosity, though, MAVEN will journey into Mars' orbit, from where it will study the planet's atmosphere.

MAVEN is part of a NASA Mars scout mission that will measure the red planet's atmosphere and learn more about its history, habitability and the sun's effects on the planet. As the first mission of its kind, scientists hope to expand our knowledge of Mars in hopes of fueling future manned missions to the red planet.

On September 21, MAVEN will finally reach its destination after a 10-month long journey. From there, six of its thruster engines will fire, slowing the spacecraft down so that it's pulled into Mars' elliptical orbit. Once in orbit, MAVEN will test its instruments for six weeks. Then, it's one-year mission begins as it takes stock of Mars' upper atmosphere.

"The MAVEN science mission focuses on answering questions about where did the water that was present on early Mars go, about where did the carbon dioxide go," says MAVEN principal investigator Bruce Jakosky from the University of Colorado, Boulder's Laboratory for Atmospheric and Space Physics. "These are important questions for understanding the history of Mars, its climate, and its potential to support at least microbial life."

According to NASA, MAVEN is on track for its rendezvous with the red planet. Most of the commands for its orbit-insertion will happen autonomously, but ground control on Earth will monitor the spacecraft's flight path and adjust it, if needed. Lockheed Martin Space Systems is responsible for this part of the spacecraft's journey.

"On Sunday evening, MAVEN will slew (turn) to point the main engines in the direction of travel and fire for about 33 minutes in order to slow down the spacecraft enough to 'capture' into Mars orbit," says NASA. "Although we have direct line of sight of MAVEN during the entire burn sequence, the observed data back on Earth will actually be viewed 12 minutes after the events occur because of the distance between Earth and Mars."

NASA is covering the event live on September 21 from 9:30 p.m. to 10:45 p.m. EDT on the NASA Channel on cable and satellite TV and on their website at www.nasa.gov/ntv.

MAVEN launched on Nov. 18, 2013, from Cape Canaveral, Florida.