NASA Delta II Launch of SMAP

The Delta II rocket lifts off from Space Launch Complex 2 at Vandenberg Air Force Base carrying the Soil Moisture Active Passive (SMAP), satellite on a mission to measure and map the Earth's soil moisture distribution and freeze/thaw state with unprecedented accuracy. Liftoff was at 6:22 a.m. PST (9:22 a.m. EST).

The unfolded solar arrays to power SMAP and the golden feedhorn for its radar and radiometer are visible in this image taken during assembly and testing.

Credit: NASA, JPL.

In orbit graphic of SMAP satellite prior to third stage burn for orbit insertion and booster decoupling.

Credit: NASA,

NASA Soil Moisture Active Passive Spacecraft (SMAP):

NASA's Soil Moisture Active Passive (SMAP) spacecraft is delivered by truck to the Astrotech payload processing facility at Vandenberg Air Force Base in California on Wednesday, Oct. 15, 2014. 

Credit: NASA

A NASA spacecraft designed to track Earth's water in one of its most important, but least recognized forms, soil moisture, now is at Vandenberg Air Force Base, California, to begin final preparations for launch in January.

The Soil Moisture Active Passive (SMAP) spacecraft arrived Wednesday at its launch site on California's central coast after traveling from NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California.

The spacecraft will undergo final tests and then be integrated on top of a United Launch Alliance Delta II rocket in preparation for a planned Jan. 29 launch.

SMAP will provide the most accurate, highest-resolution global measurements of soil moisture ever obtained from space and will detect whether the ground is frozen or thawed.

The data will be used to enhance scientists' understanding of the processes that link Earth's water, energy and carbon cycles.

Soil moisture is critical for plant growth and supplies aquifers, which are underground water supplies contained in layers of rock, sand or dirt.

Through evaporation, water in the soil cools the land surface and lower atmosphere while seeding the upper atmosphere with moisture that forms clouds and rain.

High-resolution global maps of soil moisture produced from SMAP will allow scientists to understand how regional water availability is changing and inform water resource management decisions.

"Water is vital for all life on Earth, and the water present in soil is a small but critically important part of Earth's water cycle," said Kent Kellogg, SMAP project manager at JPL.

"The delivery of NASA's SMAP spacecraft to Vandenberg Air Force Base marks a final step to bring these unique and valuable measurements to the global science community."

SMAP data also will aid in predictions of plant growth and agricultural productivity, improve weather and climate forecasts, and enhance our ability to predict the extent and severity of droughts and where floods may occur.

SMAP's freeze/thaw data will also be used to detect changes in the length of the growing season, which is an indicator of how much carbon plants take up from the atmosphere each year.

Among the users of SMAP data will be hydrologists, weather forecasters, climate scientists, and agricultural and water resource managers.

Additional users include fire hazard and flood disaster managers, disease control and prevention managers, emergency planners and policy makers.

To make its high-resolution, high-accuracy measurements, SMAP will combine data from two microwave instruments, a synthetic aperture radar and a radiometer, in a way that uses the best features of each.

The instruments can peer through clouds and moderate vegetation cover day and night to measure water in the top 2 inches (5 centimeters) of the soil.

NASA SMAP: Sophisticated Earth-observing Microwave Radiometer

This photograph shows the SMAP propellant tank after installation at NASA's Jet Propulsion Laboratory in Pasadena, Calif. 

The propulsion tank was made by ATK Space Systems in Commerce, Calif. The technicians and engineers pictured are (left to right) John Shuping, Ryan Van Schilfgaarde, Bob Path and Vinh Dang. 

Credit: NASA JPL/Corinne Gatto

A NASA team delivered in May a sophisticated microwave radiometer specifically designed to overcome the pitfalls that have plagued similar Earth-observing instruments in the past.

Literally years in the making, the new radiometer, which is designed to measure the intensity of electromagnetic radiation, specifically microwaves, is equipped with one of the most sophisticated signal-processing systems ever developed for an Earth science satellite mission.

Goddard technologists Mark Wong (front left), Damon Bradley (rear left), Lynn Miles (rear right), and Rafael A. Garcia (front right) created the digital-processing system for a new radiometer to debut on NASA’s Soil Moisture Active Passive mission. 

Credit: NASA Goddard/Pat Izzo

Its developers at NASA's Goddard Space Flight Center shipped the instrument to NASA's Jet Propulsion Laboratory where technicians will integrate it into the agency's Soil Moisture Active Passive spacecraft (SMAP), along with a synthetic aperture radar system operating at L-band (1.20-1.41 GHz), developed by JPL.

With the two instruments, the NASA mission will globally map soil moisture levels—data that will benefit climate models—when it begins operations a few months after its launch in late 2014.

In particular, the data will give scientists the ability to discern global soil moisture levels, a crucial gauge for drought monitoring and prediction, and fill gaps in scientists' understanding of the water cycle.

Also important, it could help crack an unsolved climate mystery: the location of the places in the Earth system that store carbon dioxide.

This is an artist's concept of NASA's Soil Moisture Active Passive mission. Credit: NASA/JPL

Years in the Making
Building the new radiometer took years to accomplish and involved the development of advanced algorithms and an onboard computing system capable of crunching a deluge of data estimated at 192 million samples per second.

Despite the challenges, team members believe they've created a state-of-the-art instrument that is expected to triumph over the data-acquisition troubles encountered by many other Earth-observing instruments.

The signal received by the instrument will have penetrated most non-forest vegetation and other barriers to gather the naturally emitted microwave signal that indicates the presence of moisture. The wetter the soil, the colder it will look in the data.

The instrument's measurements include special features that allow scientists to identify and remove the unwanted "noise" caused by radio-frequency interference from the many Earth-based services that operate near the instrument's microwave-frequency band.

The same noise has contaminated some of the measurements gathered by the European Space Agency's Soil Moisture and Ocean Salinity satellite (SMOS) and NASA's Aquarius satellite. These spacecraft found that the noise was particularly prevalent over land.

"This is the first system in the world to do all this," said Instrument Scientist Jeff Piepmeier, who came up with the concept at NASA Goddard.

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