(CNN)If your houseplants look thirsty, you can stick your finger in the soil to see if they need water. But if you want to check the whole planet's moisture level, you need something a bit more high tech.
NASA has just the thing. It's called the Soil Moisture Active Passive, or SMAP, satellite. It's currently scheduled to launch at 6:20 a.m. PT (9:20 a.m. ET) on January 29 from Vandenberg Air Force Base in California.