– NASA announced Jan. 8 that it had selected competing proposals to send an orbiter to Mars in 2011 to study how the red planet’s atmosphere has evolved over time.


The two Boulder, Colo.-based institutions that submitted the competing aeronomy mission proposals will each receive $2 million from NASA to spend the next nine months refining their concepts. NASA plans to select one of the proposals in late 2007 or early 2008 for full development as the
space agency’s next Mars Scout mission.


The chosen mission would have to launch by 2011 at a cost of no more than $475 million. The two finalists were selected from more than two-dozen proposals the agency received last summer.


The Mars Atmosphere and Evolution Mission, or Maven, was proposed by Bruce Jakosky of the University of Colorado, Boulder, to “address key questions about Mars climate and habitability and improve understanding of dynamic processes in the upper Martian atmosphere and ionosphere,” according to a NASA news release. NASA’s Goddard Space Flight Center,
, would manage the project.


Jakosky told Space News during a Jan. 10 interview at the Mars Exploration Program Analysis Group meeting here that the orbiter would be built by Denver-based Lockheed Martin Space Systems. Science partners for the mission include the
, the
and Goddard.


Jakosky was reluctant to discuss his proposal in detail since the competition is still underway and both finalists are going after very similar science objectives. He said Maven would employ a combination of remote-sensing and in-situ instrumentation to try to better understand the loss of the martian atmosphere into space.


The Great Escape mission, proposed by Alan Stern of the Boulder-based Southwest Research Institute, would, according to the release, “directly determine the basic processes in Martian atmospheric evolution by measuring the structure and dynamics of the upper atmosphere.” The spacecraft would also seek out and measure “potentially biogenic atmospheric constituents such as methane.”


Stern, like Jakosky, is also holding his cards close to the vest when it comes to details of the mission. He told Space News in a Jan. 10 telephone interview that the Great Escape team includes Johns Hopkins University’s Applied Physics Laboratory of Laurel, Md., Orbital Sciences Corp. of Dulles, Va., the University of Michigan and “a host of other players” but would not say what roles any of the teammates are playing.


“The central focus of [The Great Escape] is to understand the upper atmosphere of Mars well enough to help answer the questions where did the water go and where did the thick atmosphere go from the early epic when we know Mars was so much more hospitable – that is the epic when water flowed down the river valleys into the flood plains. We know that for the water to have flowed the martian atmosphere had to be thicker and we know that a very large amount of water was involved. The question is what became of that atmosphere and what become of that water. One possibility is that one or both escaped in part or in whole into space.”


Stern currently is the principal investigator on NASA’s New Horizons mission, which was launched in January 2006 on a nine-year journey to Pluto and the Kuiper Belt. The spacecraft is expected to go into hibernation soon and not awake until 2014 – the same year the Great Escape mission would conclude, Stern said.


Aeronomy had been held up as one possible scientific focus of the Mars Science and Telecommunications Orbiter mission NASA plans to launch in 2013. Doug McCuistion, NASA’s director of the Mars Exploration Program, said in a Jan. 10 interview that now that the 2011 Mars Scout mission, whichever proposal is selected, will zoom in on atmospheric physics, the 2013 mission would be focused on some other to-be-determined set of scientific objectives.


Jakosky said going head to head against another aeronomy mission poses unique challenges for his team, but said it’s a win-win for scientists interested in better understanding martian atmospheric physics.


“Whichever one wins, the science objectives are going to be addressed,” he said. “As a scientist, that’s exciting.”


NASA also announced Jan. 8 that it will spend $800,000 for St. Louis-based
researcher Alicia Wang to participate as a member of the science team for the European Space Agency’s 2013 ExoMars mission.