With all the increasing information about Mars, it is but fitting that NASA starts scouting for proposals that would further pursue Mars missions and studies. On Monday, they have narrowed down the search to two, which are proposals for future robotic missions. Included in the objectives of these proposals are the study of the red planet's atmosphere, climate and potential habitability.

According to Mary Cleave, associate administrator for NASA's Science Mission Directorate, NASA headquarters, Washington, "These mission selections represent unprecedented future research that will lead further advancing our knowledge of [Mars'] climate, and atmospheric composition."

The two finalists for the mission search are:

• Mars Atmosphere and Volatile Evolution mission, or MAVEN: The mission would provide first-of-its-kind measurements and address key questions about Mars climate and habitability and improve understanding of dynamic processes in the upper Martian atmosphere and ionosphere. The principal investigator is Bruce Jakosky, University of Colorado, Boulder. NASA's Goddard Space Flight Center, Greenbelt, Md., will provide project management.

• The Great Escape mission: The mission would directly determine the basic processes in Martian atmospheric evolution by measuring the structure and dynamics of the upper atmosphere. In addition, potentially biogenic atmospheric constituents such as methane would be measured. The principal investigator is Alan Stern, Southwest Research Institute, Boulder, Colorado. Southwest Research Institute, San Antonio, will provide project management.