NASA has never before attempted to take scientific measurements of the Earth on a global scale, but that is exactly what they intend to do with a new environmental satellite that is now mounted atop a booster rocket in California.

The launch of the Soil Moisture Active Passive (SMAP) spacecraft is set on top of a Delta 2 rocket and has been scheduled for January 29 at 6:20 a.m. local time (9:20 a.m. EST). The spacecraft is designed to detect the moisture content in land surfaces, and also determine whether land is frozen or thawed during its three-year mission.

"The relevance is (soil moisture) is a pretty sensitive indicator of future water availability and can be used in climate models to help improve forecasts," Project Manager for SMAP, Kent Kellogg says. "One of the really nice things about this mission is we have a lot of relevance for climate science, but the data is also very useful for everyday practical applications. It will improve weather forecasting significantly, drought and flood forecasting, food productivity and diseases."

The mission was created as a result of the first-ever Earth Science Decadel Survey in 2007, which ranked soil moisture missions as a top priority and high-ranking objective. 

The satellite will be capable of looking beneath the clouds, vegetation and other surfaces, and will produce new global maps every two to three days.   "It's unique because for the first time they are combining a radar instrument, which has a really fine resolution and detail in what it sees, and also a radiometer, which can see through clouds and has other benefits," researcher with the National Snow and Ice Data Center in Boulder and the Data Management Lead for the SMAP mission, Amanda Leon says.

"It will take a while to calibrate the instruments and validate the data because we will be acquiring measurements over diverse soil types, vegetation, terrain and in different climates," Kellogg says. "We have to make sure the satellite data agrees with information drawn from ground sensors in all these different circumstances."

Crews carefully transported the 2,081-pound satellite from the commercial Astrotech processing facility to the pad at Space Launch Complex 2 of Vandenberg Air Force Base on Tuesday. A combined systems check of both the rocket and spacecraft will then be performed and then the payload fairing is set for installation next week in preparation for the launch. 

A two stage Delta 2 rocket, with three strap-on solid motors, will propel the satellite into a near-polar, sun-synchronous orbit on January 29.