Friday morning NASA will launch a new Earth observing satellite that will take stock of the water hidden in the topsoil, just beneath your feet. The satellite, named SMAP - Soil Moisture Active Passive – will map the small but vital reservoir of water that lies just out of sight in reserves beneath the earth's surface.  This water plays a big role in how our planet works. 

Knowing how much water is in the soil, and whether it is frozen or thawed, has profound applications for society, from better forecasting of natural disasters like floods and droughts to helping prevent food shortages and drought conditions.

Consider the New England blizzard that hit earlier this week. The possibility of floods as it melts will depend on how saturated the soil already is. SMAP will help us predict where areas might see flooding after a substantial storm like this.   

The SMAP observatory launches from California's Vandenberg Air Force Base at 8:20 AM central time and you can watch it live along with commentary by clicking here: http://www.nasa.gov/multimedia/nasatv