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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NASA's Aquarius Sees Salty Shifts

NASA¹s Aquarius instrument has been orbiting the Earth for a year, measuring changes in salinity, or salt concentration, in the surface of the oceans. 

The Aquarius team released last September this first global map of ocean saltiness, a composite of the first two and a half weeks of data since the instrument became operational on August 25. 

Credit: NASA/GSFC/JPL-Caltech

Colourful new images chronicle the seasonal stirrings of our salty world: Pulses of freshwater gush from the Amazon River's mouth; an invisible seam divides the salty Arabian Sea from the fresher waters of the Bay of Bengal; a large patch of freshwater appears in the eastern tropical Pacific in the winter.

These and other changes in ocean salinity patterns are revealed by the first full year of surface salinity data captured by NASA's Aquarius instrument. 

"With a bit more than a year of data, we are seeing some surprising patterns, especially in the tropics," said Aquarius Principal Investigator Gary Lagerloef, of Earth & Space Research in Seattle. "We see features evolve rapidly over time." 

Launched June 10, 2011, aboard the Argentine spacecraft Aquarius/Satélite de Aplicaciones Científicas (SAC)-D, Aquarius is NASA's first satellite instrument specifically built to study the salt content of ocean surface waters. 

Salinity variations, one of the main drivers of ocean circulation, are closely connected with the cycling of freshwater around the planet and provide scientists with valuable information on how the changing global climate is altering global rainfall patterns. 

The salinity sensor detects the microwave emissivity of the top 1 to 2 centimeters (about an inch) of ocean water -- a physical property that varies depending on temperature and saltiness. 

The instrument collects data in 386 kilometer-wide (240-mile) swaths in an orbit designed to obtain a complete survey of global salinity of ice-free oceans every seven days. 

The Changing Ocean
The animated version of Aquarius' first year of data unveils a world of varying salinity patterns. The Arabian Sea, nestled up against the dry Middle East, appears much saltier than the neighboring Bay of Bengal, which gets showered by intense monsoon rains and receives freshwater discharges from the Ganges and other large rivers. 

Another mighty river, the Amazon, releases a large freshwater plume that heads east toward Africa or bends up north to the Caribbean, depending on the prevailing seasonal currents. 

Pools of freshwater carried by ocean currents from the central Pacific Ocean's regions of heavy rainfall pile up next to Panama's coast, while the Mediterranean Sea sticks out in the Aquarius maps as a very salty sea. 

One of the features that stand out most clearly is a large patch of highly saline water across the North Atlantic. This area, the saltiest anywhere in the open ocean, is analogous to deserts on land, where little rainfall and a lot of evaporation occur. 

A NASA-funded expedition, the Salinity Processes in the Upper Ocean Regional Study (SPURS), traveled to the North Atlantic's saltiest spot last fall to analyze the causes behind this high salt concentration and to validate Aquarius measurements.


"My conclusion after five weeks out at sea and analyzing five weekly maps of salinity from Aquarius while we were there was that indeed, the patterns of salinity variation seen from Aquarius and by the ship were similar," said Eric Lindstrom, NASA's physical oceanography program scientist, of NASA Headquarters, Washington, and a participant of the SPURS research cruise.


NASA Goddard Space Centre

Budget Cuts Hit NOAA Aquarius Underwater Laboratory - YouTube

The future of National Oceanic and Atmospheric Administration's (NOAA) Aquarius Reef Base laboratory, the world's only undersea lab appears bleak owing to budget cuts from the Federal Government.

The NOAA was under orders to tighten up and the $3 million annual budget for Aquarius was eliminated, ABC News reported.

Though an Aquarius Foundation is trying to raise funds to maintain the lab, its efforts may not raise adequate funds to fund active work from the lab. Meanwhile, the lab's supporters are hoping a large donor will come forward amidst criticism that it is expensive to maintain.

Even when not in use, divers must ensure that its systems work properly every week in salt water.

Aquarius is the only undersea laboratory dedicated to marine science operating in the world.

Owned by the National Oceanic and Atmospheric Administration (NOAA) and managed by the University of North Carolina at Wilmington (UNCW), Aquarius operates 4.5 kilometers offshore of Key Largo, Florida 20 meters beneath the surface.

Aquarius was originally conceived and funded by NOAA's National Undersea Research Program (NURP) in the mid 1980s.

The underwater laboratory was built by Victoria Machine Works in 1986-87. Initial deployment in the U.S. Virgin Islands before Hurricane Hugo struck in 1989, and devastated St. Croix.

Aquarius was retrieved from the seafloor in 1990 and was moved to North Carolina where it was refurbished and then redeployed in the Florida Keys National Marine Sanctuary in 1993.

Aquarius Satellite Images Measures Ocean's Salt from Space

This week marks the one-year anniversary of a NASA mission designed to help answer an age-old question: How salty is the sea?

The Aquarius instrument aboard the Satélite de Aplicaciones Científicas (SAC)-D is providing some of the first large-scale pictures of ocean salinity around the world, and how it changes from week to week — which influences everything from ocean circulation to the global water cycle.

The satellite was launched on June 10, 2011. Over the last year, the instrument has sent back data showing the sometimes striking variations in salinity in the world's oceans and seas, and has also confirmed Earth-bound observations.

Oceanographers have long known that the Atlantic Ocean is saltier than the Pacific and Indian oceans, and the satellite images show the same.

It has also shown that the world's longest rivers carry tremendous amounts of fresh water from land and spread plumes far into the sea, and in the tropics, extra rainfall makes equatorial waters somewhat fresher.

The satellite technically measures the "brightness temperature" of a tiny layer atop ocean waters — a slice just 0.4 inches (1 centimeter) thick. Land masses tend to be "brighter" than water, so any measurements near the coast are skewed by their proximity to land.

But as the mission progresses, NASA engineers should be able to sort out the signals in the data caused by bright land, and get the true measure of salinity in coastal areas.

An overarching question in climate research is to understand how changes in the Earth's water cycle — which encompasses everything from rainfall to evaporation to river runoff and other factors — is linked to ocean circulation and climate, Gary Lagerloef, the Aquarius principal investigator, said in a statement.

The instrument is the first designed to study ocean salinity from space. It takes 300,000 measurements per month, using three sensors, for a mission that is a joint U.S.-Argentina effort.

NASA 16th NEEMO Expedition

The 16th NEEMO expedition will commence June 11, 2012. NEEMO, or NASA Extreme Environment Mission Operations, is an aquatic program that uses the under water base Aquarius to test technologies for use in space.

“Water is a nice way to free your body and get to explore a different way of movement. Since we’re so stuck with walking here on Earth, it’s nice to float around, flip around — just like in space,” says mission commander Dottie Metcalf-Lindenburgher.

Water provides a reasonable analogy for the space environment since buoyancy mimics reduced gravity in some respects.

NEEMO crewmembers are known as aquanauts, although some have or will achieve astronaut status as well. The 16th expedition is led by Dottie Metcalf-Lindenburgher, a Space Shuttle veteran.

Timothy Peake, an up and coming ESA astronaut and Kimiya Yui a rising JAXA astronaut, will also join the crew, along with veteran aquanaut and Mars Rover principal investigator Steve Squyres.

The two week mission will work on how to take a sample from an asteroid. “If you just do something as simple as hit a rock with a hammer, you’re going to go flying off into space, so we’ve got to develop a whole new set of tricks and tools for operating on the surface of an asteroid,” says Squyres.

Past missions tested jetpacks, which did not work well for staying in one spot. The current crew will test miniature submarines. “Imagine this little submarine with a six-foot-long beam sticking off the front of it and an astronaut on the front of that like a hood ornament,” Squyres says.

Asteroids could be a NASA target for a manned mission beyond 2025, but they may have to play catch-up as more players become interested in asteroids as celestial targets.

JAXA already had a successful asteroid sample return mission with Hayabusa in 2010 and is working on a second one.