Soil Moisture Active Passive (SMAP)

During our last visit to NASA’s JPL, we learned about their current project, SMAP. SMAP stands for Soil Moister Active Passive. The project involves a satellite that that will be able to scan to earth and measure the level of moisture in soil as well as collect data on ground that is frozen versus ground that is thawed. The foundation for SMAP was built on NASA’s previous project, Hydros. Hydros was selected in 2002 as an alternate Earth System Science Pathfinder or ESSP. The mission basically had the same objective as SMAP in that they both measure soil moisture and frozen/thawed ground. In 2005, those working on Hydros were notified that they were not going to receive the funds they needed to finish the project due to budget cuts. Though the project was left incomplete, they were able to use different levels from Hydros as a starting point for SMAP. The amount of effort and progress already made on Hydros was one of the primary reasons that SMAP was chosen by the decadal survey. Out of over a hundred submitted missions, SMAP was one of four projects chosen for the top Tier-1 2010-2013 launch.

            SMAP has great potential to help people all over the world. It is pretty amazing that these scientists were able to develop the algorithms and technology to measure soil moister from space! What is also impressive is the massive amount of people who have collaborated on this project. So many people working on so many different aspects of the project, yet they are all able to keep everything constant and coherent and make sure that all parts fit and work together. SMAP will be very helpful in the future. It will give us the ability to spot drought patterns and predict floods and landslides. Being able to predict droughts would be very helpful to the agricultural industry and being able to warn people of floods and landslides could save lives. SMAP can also see what land is frozen and what land is thawed. By tracking change in frozen/thawed land could help predict the growing season and the seasonal rises of CO2 that come with it. This data would also be beneficial to research on climate change. By tracking the frost patterns each year they can tell which climates are warming up, and which ones are cooling down. Because the data collected by SMAP will be available to any one who wants it, there may be even ways in which that data will be useful that the scientists behind SMAP did not even think of.

            One crucial piece of equipment on SMAP is the large antenna. The antenna is 6 meters in diameter and is made of a reflective mesh with a parabolic shape facing earth. The parabolic shape of the mesh spreads out signals from the radar to a larger diameter. The shape also causes signals coming from the earth to redirect into the feed horn. In order to send SMAP into space, they needed to make the antenna have the ability to collapse and fold into a small space. To do this the structure of the antenna is made of tubes with wires running through them. After the arm has fully extended the wires are pulled in, which causes the tubes to expand out and pop into place. In testing on earth this process takes about a half hour.