NASA's MAVEN set to enter Mars' orbit Sunday night

NASA will broadcast MAVEN's long-anticipated arrival at Mars in a live webcast Sunday night. India's Mars Obiter Mission will reach the Red Planet Wednesday. 

A NASA spacecraft built to study the atmosphere of Mars like never before will arrive at the Red Planet tonight (Sept. 21) and you can watch it live online.

After 10 months in deep-space, NASA's Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft is expected to enter orbit around Mars and begin a one-year mission studying the planet's upper atmosphere. The Mars arrival will cap a 442 million-mile (711 million kilometers) trek across the solar system.

You can watch the MAVEN spacecraft arrive at Mars on Space.com, courtesy of NASA TV, in a live webcast that runs from 9:30 p.m. to 10:45 p.m. EDT (0130 to 0245 GMT). If all goes well, MAVEN will enter orbit around Mars at 9:50 p.m. EDT (0250 GMT), according to NASA officials.

 "So far, so good with the performance of the spacecraft and payloads on the cruise to Mars," David Mitchell, NASA's MAVEN project manager at the Goddard Space Flight Center in Greenbelt, Maryland, said in a statement. "The team, the flight system, and all ground assets are ready for Mars orbit insertion."

The $671 million MAVEN spacecraft eight instruments to study the Martian atmosphere in detail. It is one of two missions that launched toward Mars last November and are making their arrival this month. The other probe is India's Mars Orbiter Mission, which launched just before MAVEN and will arrive at the Red Planet on Wednesday (Sept. 24).

The atmosphere of mars

Mars' upper atmosphere is an escape zone for molecules floating dozens of miles from the planet's surface. Scientists think that, as the solar wind hits the atmosphere, the radiation strips away the lighter molecules and flings them into space forever. [NASA's MAVEN Spacecraft: 10 Surprising Facts]

"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," said Bruce Jakosky, the mission's principal investigator at 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."

Dust storms and solar activity

Bougher is interested in studying the speed at which ions (charged atoms) and neutral gases leave the atmosphere of Mars. This process could change with solar activity, and also as dust storms sweep the planet's surface. MAVEN will arrive just as the Martian storm season begins, Bougher said.

"If we are so fortunate as to get a global dust storm or a reasonable dust storm, the lower atmosphere will inflate like a balloon, and the upper atmosphere will inflate on top of that," he said. "The processes have not been studied well before."

Jakosky, MAVEN's lead researcher, is examining how stable isotopes (element types) of hydrogen and its heavier version, deuterium, changed over time. In theory, as the solar wind hit the Red Planet's atmosphere, the lighter hydrogen in the atmosphere should have been stripped away and decreased proportionally near Mars.

"One of the really overarching questions about Mars is whether there was ever life," Jakosky said in a NASA news conference Wednesday (Sept. 17).

"We're trying to understand the context in which life might have existed," Jakosky said. Any life on Mars would have interacted with its environment, so MAVEN could help with NASA's ongoing research into the "boundary conditions" for life, he added.

MAVEN will began making science measurements around Nov. 8, but the spacecraft will take a time-out from its commissioning phase to watchComet Siding Spring pass close by on Oct. 19. So far, it looks like there won't be enough dust to hurt the spacecraft, but MAVEN will be maneuvered to minimize its exposure to the comet's dust as a safety precaution.

Visit Space.com tonight for complete coverage of NASA's MAVEN Mars orbiter arrival.

Follow Elizabeth Howell @howellspace, or Space.com @Spacedotcom. We're also on Facebook and Google+. Originally published on Space.com.

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