Soil Moisture Satellite With Rotating Antenna to Launch on January 29
Posted on January 4, 2015
NASA is set to launch a soil moisture satellite on January 29th. The Soil Moisture Active Passive (SMAP) instrument will feature a spinning satellite that NASA calls the spinning lasso. It makes about 14 revolutions per minute.
The main parts on the SMAP include a radar, radiometer and the rotating antenna. The satellite will cover the globe ever three days. NASA says the instrument will provide the highest-resolution and most accurate measurement ever taken of soil moisture on Earth. Soil moisture makes up just a tiny fraction of Earth's water but as NASA says soil moisture has a "disproportionately large effect on weather and agriculture."
Wendy Edelstein, the SMAP instrument manager at NASA's Jet Propulsion Laboratory, says the spinning lasso caused NASA engineers a "lot of angst." The antenna has to fit in a space the size of a kitchen trash can during launch. It then has to unfold "so precisely that the surface shape of the mesh is accurate within about an eighth of an inch (a few millimeters)." A ring of lightweight graphite covers the edge of the mesh.
Edelstein says, "Making sure we don't have snags, that the mesh doesn't hang up on the supports and tear when it's deploying -- all of that requires very careful engineering. We test, and we test, and we test some more. We have a very stable and robust system now."
You can read more about the SMAP video here on nasa.gov. Here is a video about SMAP and how scientists will be able to use the data it collects. Take a look: