Spaceflight Insider

SMAP mission continues despite loss of radar

CGI rendition of SMAP in orbit.

NASA’s SMAP mission, launched in January to map global soil moisture and detect whether soils are frozen or thawed, continues to produce high-quality science measurements with one of its two instruments. Image & Caption Credit: NASA

Designed to help scientists understand Earth’s water, energy, and carbon cycles, NASA’s Soil Moisture Active Passive (SMAP) observatory provides vital information for the study of our climate. The satellite, launched in January, has two science instruments that map global soil moisture. The spacecraft can also detect if soils are frozen or thawed.

NASA says that the SMAP mission will continue despite the loss of the main active radar instrument, which stopped transmitting on July 7, 2015. The problem appears to be centered around the radar’s high-power amplifier (HPA). The HPA is designed to boost the power level of the radar’s pulse. This boost to over 500 watts ensured the energy scattered from the Earth’s surface could be accurately measured. Engineers stopped working on the radar in August, declaring the instrument a loss.

SMAP animated GIF

CGI depiction of SMAP’s motion in orbit. GIF Image Credit: NASA

Even with the loss of the radar instrument, NASA still plans to release the first set of data from SMAP sometime later in September. All other instruments aboard the spacecraft appear to be running normally.

SMAP’s systems are designed to compliment each other. With both the active radar and the other instrument, a passive radiometer, SMAP could resolve areas of freeze-thaw to within 1.9 miles (3 kilometers) and detect soil moisture with a resolution of 5.6 miles (9 kilometers). The loss of the active radar means that resolution will be limited to areas of 25 miles (40 kilometers). If the coincident data technique is successful, the design may find its way on board future spacecraft.

NASA was able to collect over three months of coincident measurements before the active radar shut down. These measurements are the first of their kind ever produced and the information could prove to be extremely valuable. NASA will now adjust the algorithms used on the data to work within the existing 25-mile resolution area. NASA is currently looking for a way to possibly improve the resolution from the radiometer instrument.

SMAP is managed for NASA’s Science Mission Directorate in Washington by JPL, with instrument hardware and science contributions made by NASA’s Goddard Space Flight Center in Greenbelt, Maryland. JPL built the spacecraft and is responsible for project management, system engineering, radar instrumentation, mission operations, and the ground data system. Goddard is responsible for the radiometer instrument and science data products.



Joe Latrell is a life-long avid space enthusiast having created his own rocket company in Roswell, NM in addition to other consumer space endeavors. He continues to design, build and launch his own rockets and has a passion to see the next generation excited about the opportunities of space exploration. Joe lends his experiences from the corporate and small business arenas to organizations such as Teachers In Space, Inc. He is also actively engaged in his church investing his many skills to assist this and other non-profit endeavors.

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