US Mars spacecraft enters Mars orbit

US space agency NASA said its first spacecraft dedicated to exploring the upper atmosphere of Mars entered its Mars orbit Sunday night, completing a 10-month journey of 442 million miles (711 million km).

NASA's Mars Atmosphere and Volatile Evolution (MAVEN) began to enter Martian orbit at about 9:50 pm EDT Sunday (0150 GMT Monday), firing six small thruster engines to steady itself.

About 33 minutes later, the spacecraft was reduced to a speed that allowed it to be pulled into an elliptical orbit.

"Based on observed navigation data, congratulations, MAVEN is now in orbit," an official with the US space agency announced on NASA TV.

Because of the distance between Earth and Mars, data transmitted by the spacecraft were received by mission controllers on Earth with a 12-minute time delay.

Over the next six weeks, MAVEN will begin a commissioning phase that includes maneuvering into its final orbit and testing its instruments and science-mapping commands, NASA said.

Thereafter, MAVEN will begin its one-Earth-year primary mission to measure the composition, structure and escape of gases in Mars' upper atmosphere and its interaction with the sun and solar wind, NASA said.

"As the first orbiter dedicated to studying Mars' upper atmosphere, MAVEN will greatly improve our understanding of the history of the Martian atmosphere, how the climate has changed over time, and how that has influenced the evolution of the surface and the potential habitability of the planet," NASA Administrator Charles Bolden said in a statement.

"It also will better inform a future mission to send humans to the Red Planet in the 2030s."

The primary mission includes five "deep-dip" campaigns, in which MAVEN's periapsis, or lowest orbit altitude, will be lowered from 150 km to about 125 km.

These measurements will provide information about where the upper and lower atmospheres meet, giving scientists a full profile of the upper tier, NASA said.

"This was a very big day for MAVEN," said David Mitchell, MAVEN project manager from NASA's Goddard Space Flight Center. "We're very excited to join the constellation of spacecraft in orbit at Mars and on the surface of the Red Planet."

MAVEN was launched on Nov. 18, 2013, from Cape Canaveral, Florida, carrying three instrument packages. It is the first spacecraft dedicated to exploring the upper atmosphere of Mars.

Two days after MAVEN's arrival, another spacecraft, India's Mars Orbiter Mission, is expected to enter the Red Planet's orbit. It was also launched in November.

MAVEN is the 10th orbiter the US space agency sends to Mars, and three of them have failed. Currently, there are three other active spacecraft orbiting the Red Planet: Mars Odyssey launched in 2001, the European Space Agency's Mars Express launched in 2003 and NASA's Mars Reconnaissance Orbiter launched in 2005.

NASA also has two active rovers currently studying Mars on the planet's surface: Opportunity launched in 2003 and Curiosity launched in 2011.