On the final stretch of a marathon 442 million-mile voyage, NASA's MAVEN spacecraft will perform a make-or-break rocket burn Sunday to brake into orbit around Mars and begin an extensive study of the red planet's atmosphere.

Artist's concept of the MAVEN spacecraft at Mars. Credit: NASA
 
The Mars orbit insertion maneuver is due to begin at 9:50 p.m. EDT Sunday (0150 GMT Monday), and MAVEN will fire its six main engines for 33 minutes to slow down enough for Martian gravity to capture the spacecraft into a looping, highly elliptical orbit.

Ground controllers inside an operations room at Lockheed Martin Corp. in Denver, the manufacturer of the MAVEN spacecraft, will oversee the critical maneuver.

But they will receive data from the orbiter on a 12-minute time delay. The interplanetary distance between Earth and Mars means engineers on the ground will not have the ability to track the burn or send commands to MAVEN in real-time.

Sunday's arrival of the Mars Atmosphere and Volatile Evolution, or MAVEN, mission concludes a 10-month journey since the probe blasted off Nov. 18, 2013, from Cape Canaveral, Fla., aboard a United Launch Alliance Atlas 5 rocket.

The main objective of the $671 million mission is to find out how Mars evolved from a habitable world into the barren, desert planet scientists see today.

"The MAVEN mission is about understanding the history of the climate on Mars," said Bruce Jakosky, the mission's chief scientist from the University of Colorado at Boulder's Laboratory for Atmospheric and Space Physics. "We're going to be exploring an aspect of the Martian atmosphere and upper atmosphere that really has not been explored in detail by any spacecraft to date."

MAVEN will initially enter a 35-hour-long orbit around Mars. Six more engine burns are on tap over the next several weeks to adjust the probe's trajectory to reach an operational science orbit with a high point of 3,900 miles and a low point of 90 miles above Mars.

The mission's ground team will also commission the orbiter's eight science instruments to prepare the sensors for their observations of the Martian atmosphere and the solar wind.

Within six weeks, officials plan have MAVEN in its science orbit and ready for a one-year primary mission.

Later in the mission, MAVEN will lower its orbit for a series of five "deep dips" into the upper fringes of the atmosphere down to an altitude of 77 miles to sample Martian air from closer to the surface.

MAVEN will join NASA's two other operational Mars orbiters at the red planet -- the Mars Reconnaissance Orbiter and Mars Odyssey -- along with the European Space Agency's Mars Express spacecraft.

With NASA's Curiosity and Opportunity rovers crawling around the Martian surface, the arrival of MAVEN will put the number of operational Mars missions at six.

The number won't stay there for long.

India's first interplanetary spacecraft, the Mars Orbiter Mission, is scheduled fly into orbit around the red planet Wednesday.

Follow Stephen Clark on Twitter: @StephenClark1.