WASHINGTON — NASA gave the green light Oct. 4 to what is expected to be the last of its Mars Scout missions, a $438 million probe that could help scientists understand how the red planet lost much of its atmosphere, agency officials said Oct. 6.

David Mitchell, project manager for the Mars Atmosphere and Volatile Evolution (MAVEN) mission at NASA’s Goddard Space Flight Center in Greenbelt, Md., said a confirmation review team recently signed off on the mission’s detailed plans, instruments, budget and schedule.

Passing the milestone allows the MAVEN team to begin building flight hardware within a fixed budget and schedule that would see the 2,500-kilogram spacecraft launch in late November 2013.

“We are staying consistent with our approach since day one in terms of our cost requirements, and over the last year is where we’ve really fleshed this out on the scope of work,” Mitchell said in an Oct. 6 interview, adding that MAVEN is on track to complete its critical design review in July 2011. That review requires an independent team to examine MAVEN’s detailed systems design and, if approved, allows the project team to assemble the spacecraft and its instruments.

NASA expects MAVEN to arrive at Mars in the fall of 2014 and enter an elliptical orbit ranging from 145 kilometers to 6,230 kilometers above the martian surface. The yearlong mission is designed to sample the planet’s upper atmosphere in an effort to understand a dramatic climate change that left Mars unable to support the presence of liquid water on its surface.

Mitchell said MAVEN will host eight instruments, including a mass spectrometer built at Goddard and an imaging ultraviolet spectrometer built by the Laboratory for Atmospheric and Space Physics at the University of Colorado, Boulder.

The University of California, Berkeley will handle the remaining six instruments, including solar wind electron and ion analyzers, the Langmuir Probe and Waves Experiment, a suprathermal and thermal ion composition probe, a solar energetic particle detector and a pair of magnetometers.

Mitchell said MAVEN’s $438 million price tag excludes the cost of launching the spacecraft on a yet-to-be-determined launch vehicle and building a telecommunications relay payload that will support rover missions. NASA’s Jet Propulsion Laboratory, Pasadena, Calif., is responsible for the relay hardware.

Lockheed Martin Space Systems is building MAVEN based on the spacecraft platform it used for NASA’s 2001 Mars Odyssey and Mars Reconnaissance Orbiter missions.

All eight MAVEN instruments and the communications relay package are expected to arrive at the company’s Denver facility by August 2012 for integration with the spacecraft. Final delivery to Cape Canaveral Air Force Station, Fla., is set to occur one year later in preparation for launch during a 20-day window that opens Nov. 18, 2013.

Mitchell said if NASA misses that window, the mission would need to wait 26 months for a new launch window. Guy Beutelschies, MAVEN project manager for Lockheed Martin Space Systems, said the company is determined to make the November 2013 window.

“We assume that if we don’t make that date, we may not be allowed to wait two years and launch again,” Beutelschies said in an Oct. 6 interview. “We’re working extremely hard to make sure we hit that launch date.”

NASA picked MAVEN in 2008 as the second in a planned series of low-cost, scientist-led Mars Scout missions. Earlier this year, however, NASA decided to discontinue the Scout program and join the European Space Agency in 2016 on the first of several proposed joint Mars missions.