SMAP - Murphy

SMAP, or soil, moisture, active, passive, is the latest major project coming out of NASA’s Jet Propulsion Laboratory. It is on of the four-tier missions that have been recommended by the National Research Councils Committee on Earth Science and Application from Space. Mission proposals are submitted to this committee where then, after a long review process, the most important missions are chosen. SMAP started with one single scientist, interested in soil moisture; that then grew to a couple scientists and eventually a large group of scientists were out on the field collecting data. But this was not enough. These scientists had bigger plans in mind. If they wanted to get an accurate reading of soil moisture over a large plain of land, they were going to need serious technology; particularly technology in the air. So a proposal was sent to the National Research Councils Committee and was later chosen to go through as a top priority mission.

So why is soil moisture so important?

Soil moisture can actually tell us a lot about our planet even though it only counts for less than .00005% of the water on earth. But by measuring this small percentage of water we can predict agricultural success or failure. But most importantly we can predict the weather. A greater amount of soil moisture leads to a greater amount of precipitation or visa-versa. Soil moisture also works like sweat does to humans. Sweat cools us down; soil moisture cools the earth and if there is a lack of soil moisture, the warmer the earth will be. To simply put it, soil moisture affects the evolution of climate. As we have noticed in recent years, our planet is going through major climate changes. The Midwest in North America is getting pounded with cold weather, and the Southwest states are experiencing a lack of winter, more so than they normally do. By measuring soil moisture over large areas of land, we will have a better understanding of why the weather is changing and where climate in all areas of the world are likely headed.

To collect this important data, the satellite is equipped with a gold reflective “mesh”, a feed horn, radar and a radiometer. The radar produces a small radio wave, that then gets multiplied thought a positive and negative sided channel that feeds the radio wave into various energy boxes to finally come out in the end, a much stronger radio wave, that is then strong enough to reflect off the gold mesh down to earth where it is then reflected back to the gold mesh, through the feed horn and into the radiometer which measures the strength of the reflected frequency and then finally sent back to us back on earth for analyzing. The satellite will be able to measure all soil moisture on the earth in a mere 3 days!