NASA acquired the aircraft from the U.S. Air Force in 2007. They were originally developed for surveillance and reconnaissance missions. Now researchers are modifying them for their first extensive earth science missions. "We can get high resolution in situ measurements, and that is really the gold standard, and something that we have never before been able to do," says Randy Albertson, director of NASA's Airborne Science Program in the earth science division at Dryden.

The instruments onboard for the first mission include: a LIDAR instrument that uses a laser pulse to measure the shape, size, and density of clouds and aerosols; a spectrograph that measures and maps pollutants like nitrogen dioxide, ozone, and aerosols; an ultraviolet photometer for ozone measurements; a gas chromatograph to calculate greenhouse gases; a handful of other instruments that can accurately measure atmospheric water vapor and ozone-depleting chlorofluorocarbons ; and high-definition cameras to image the ocean colors and learn about their biological processes. (See a full listing of payload here.)

The researchers will also be able to sample parts of the atmosphere that they have not been able to reach or monitor for long durations--the upper troposphere and lower stratosphere. The aircraft can fly at an altitude of 19.812 kilometers and travel nearly 22,800 kilometers. That part of the atmosphere is "a crucial region that responds to and contributes to climate change at the surface, and we have come to realize that it is highly undersampled," says David Fahey, co-project scientist and a research physicist at NOAA's Earth Science Research Lab in Boulder, CO. "If you don't know what is going on in certain regions of the atmosphere, you will misinterpret what is going on at the surface."

NASA and Northrop Grumman modified the aircraft to be a plug-in-play system, so that instruments can be easily taken off and new ones installed, depending on the mission. The plane can also be redesigned for a specific mission, if necessary.

"The planes are really robotic satellite-aircraft hybrids that are going to revolutionize the way we do science," Newman says. The next mission will be to study hurricanes in the Caribbean, and will include a new suite of instruments for the planes.