NASA's Soil Moisture Active Passive, SMAP, will measure moisture in the Earth's soil, which will help farmers combat the effects of drought.

Set to launch on Jan. 29 in California, SMAP will orbit the Earth every three days or less to measure moisture in the top two inches of soil with the highest accuracy and resolution, NASA said in a press release.

The spacecraft is equipped with radar to transmit and receive microwaves it sends toward Earth, a radiometer to measure microwaves caused by water in soil and a 19.7 foot rotating mesh antenna, the largest ever deployed in space.

The almost 20 foot antenna will spin at about 14 revolutions per minute, one per four seconds, and was designed to fit into a one-by-four-foot space by engineers at NASA's Jet Propulsion Lab in Pasadena, California.

"We call it the spinning lasso," NASA instrument manager Wendy Edelstein said.

SMAP will help scientists and farmers by giving them earlier warnings of droughts and providing more detailed moisture maps.

"SMAP can assist in predicting how dramatic drought will be, and then its data can help farmers plan their recovery from drought," Narendra Das, a water and carbon cycle scientist for NASA, said.