SMAP observatory unfurls large science antenna structure Posted on February 25, 2015 by Justin Ray CAPE CANAVERAL — Deploying its marquee element in space Tuesday, NASA’s new Soil Moisture Active Passive spacecraft took a major step towards realizing its science potential.
SMAP unfurled a 19.7-foot lightweight, gold, rip-resistant, mesh reflector antenna atop a boom structure that will spin at 14.6 rpm, completing one rotation every four seconds.
Having unfolded the 16-foot-long boom last week, Tuesday saw the antenna successfully extended. The deploy started at 9:21 and finished by 9:55 a.m. PST as controllers watched fr om the Jet Propulsion Laboratory.
“Fantastic. We had a very nominal deployment of the reflector,” said Kent Kellogg, the SMAP project manger at JPL.
Astro Aerospace, part of Northrop Grumman, builder of deployable structures and mechanisms for spaceflight, produced the antenna reflector system for SMAP.
“Whenever you deploy a large structure like this in space it’s always a challenge. Our ability to test it on the ground in the same way we deploy it in space is limited because of the gravity-offloading that is required. So this was our most significant challenge post-launch,” Kellogg added.
The antenna was stowed in a 12-inch-diameter, four-foot-long package for launch. Initially, it was allowed to “bloom” outward to 7 feet in diameter before being driven by a motor and piano wire to a tight, full 20-foot expanse.
“The reflector is in good health. It has the structural stiffness properties that match almost perfectly with pre-launch predictions. That’s very good news for us,” Kellogg said.
Upcoming in the next month, the science instruments will be checked out and the science-gathering orbital altitude will be achieved.
“It’s not a big orbit raising event, it’s more circularization and some minor adjustments. The Delta 2 put us pretty close to wh ere we needed to be,” Kellogg said.
In the second half of March, the spin-up sequence begins for the antenna.
The launch lock that held the spin mechanism fixed will be released on March 19. The spinning initially goes to 5 rpm on March 23 for a few days of testing before gradually stepping up to the nominal 14.6 rpm on March 26.
“Once we get everything spun up and operating, that’ll be another big milestone for us. We look forward to starting to get some of our science data down and processed, and seeing just how good the data ultimately will be for soil moisture and freeze/thaw state,” Kellogg said.
SMAP was carried into space Jan. 31 atop a United Launch Alliance Delta 2 rocket from Vandenberg Air Force Base, California. The three-year mission will measure the the moisture content in the top two inches of soil on a global scale.
“SMAP, or as we call it the Soil Moisture Active Passive project, will be monitoring the water that lives and moves through the soil,” said Christine Bonniksen, SMAP program executive at NASA Headquarters
“Soil moisture is a key part of the three cycles that support life on this planet — the water cycle, the energy cycle and the carbon cycles,” she added. “These things affect human interests — floods, drought, disease control, weather.”
“This data will benefit not only scientists seeking better understanding of our planet’s climate environment, but it’s also a boon for weather forecasters, agriculture and water resource managers, emergency planners and policy makers,” added Geoff Yoder, a deputy associate administrator at NASA’s Science Mission Directorate.
“SMAP is another example how NASA is making a difference in people’s lives around the world.”
NASA's new Soil Moisture Active Passive (SMAP) mission to map global soil moisture and detect whether soils are frozen or thawed has begun science operations.
Launched Jan. 31 on a minimum three-year mission, SMAP will help scientists understand links among Earth's water, energy and carbon cycles; reduce uncertainties in predicting climate; and enhance our ability to monitor and predict natural hazards like floods and droughts. SMAP data have additional practical applications, including improved weather forecasting and crop yield predictions.
During SMAP's first three months in orbit, referred to as SMAP's "commissioning" phase, the observatory was first exposed to the space environment, its solar array and reflector boom assembly containing SMAP's 20-foot (6-meter) reflector antenna were deployed, and the antenna and instruments were spun up to their full speed, enabling global measurements every two to three days.
The commissioning phase also was used to ensure that SMAP science data reliably flow from its instruments to science data processing facilities at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, and the agency’s Goddard Space Flight Center in Greenbelt, Maryland.
"Fourteen years after the concept for a NASA mission to map global soil moisture was first proposed, SMAP now has formally transitioned to routine science operations," said Kent Kellogg, SMAP project manager at JPL. "SMAP's science team can now begin the important task of calibrating the observatory's science data products to ensure SMAP is meeting its requirements for measurement accuracy."
Together, SMAP's two instruments, which share a common antenna, produce the highest-resolution, most accurate soil moisture maps ever obtained from space. The spacecraft’s radar transmits microwave pulses to the ground and measures the strength of the signals that bounce back from Earth, whereas its radiometer measures microwaves that are naturally emitted from Earth’s surface.
"SMAP data will eventually reveal how soil moisture conditions are changing over time in response to climate and how this impacts regional water availability,” said Dara Entekhabi, SMAP science team leader at the Massachusetts Institute of Technology in Cambridge. “SMAP data will be combined with data from other missions like NASA's Global Precipitation Measurement, Aquarius and Gravity Recovery and Climate Experiment to reveal deeper insights into how the water cycle is evolving at global and regional scales."
The first global view of SMAP's flagship product, a combined active-passive soil moisture map with a spatial resolution of 5.6 miles (9 kilometers), shows dry conditions in the Southwestern United States and in Australia's interior. Moist soil conditions are evident in the U.S. Midwest and in eastern regions of the United States, Europe and Asia. The far northern regions depicted in these SMAP maps do not indicate soil moisture measurements because the ground there was frozen.
Zooming in on the data allows a closer look at the benefits of combining SMAP's radar and radiometer data. A few days before SMAP collected data over the central and southern United States on April 27, intense rainstorms pounded northern Texas. The areas affected by the storm in northern Texas and the Gulf Coast are visible in great detail. Such detail can be used to improve local weather forecasts, assist in monitoring drought in smaller watersheds, and forecast floods.
Over the next year, SMAP data will be calibrated and validated by comparing it against ground measurements of soil moisture and freeze/thaw state around the world at sites representing a broad spectrum of soil types, topography, vegetation and ground cover. SMAP data also will be compared with soil moisture data from existing aircraft-mounted instruments and other satellites.
Preliminary calibrated data will be available in August at designated public-access data archives, including the National Snow and Ice Data Center in Boulder, Colorado, and Alaska Satellite Facility in Fairbanks. Preliminary soil moisture and freeze/thaw products will be available in November, with validated measurements scheduled to be available for use by the general science community in the summer of 2016.
NASA uses the vantage point of space to increase our understanding of our home planet, improve lives, and safeguard our future. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records. The agency freely shares this unique knowledge and works with institutions around the world to gain new insights into how our planet is changing.
High-resolution global soil moisture map from SMAP's combined radar and radiometer instruments, acquired between May 4 and May 11, 2015, during SMAP's commissioning phase. The map has a resolution of 5.6 miles (9 kilometers) >>
News | July 10, 2015
SMAP Team Investigating Radar Instrument Anomaly
Mission Status Report
Mission managers at NASA's Jet Propulsion Laboratory, Pasadena, California, are assessing an anomaly with the radar instrument on NASA's Soil Moisture Active Passive (SMAP) satellite observatory. The radar is one of two science instruments on SMAP used to map global soil moisture and detect whether soils are frozen or thawed.
On July 7, at about 2:16 p.m. PDT, SMAP's radar halted its transmissions. All other components of the spacecraft continued to operate normally, including the radiometer instrument that is collecting science data.
An anomaly team has been convened at JPL and is reviewing observatory and instrument telemetry and science data. Telemetry indicates no other issues with the spacecraft.
SMAP launched Jan. 31, 2015. Its mission is to help scientists understand links among Earth's water, energy and carbon cycles; reduce uncertainties in Earth system modeling; and enhance our ability to monitor and predict natural hazards like floods and droughts. SMAP data have additional practical applications, including improved weather forecasting and crop yield predictions.
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.
More information on the SMAP mission is online at:
NASA Could Reboot Balky SMAP Radar In ‘Late August’ by Dan Leone — August 11, 2015
Artist's concept of SMAP satellite. Credit: NASA
WASHINGTON — One of the two main science instruments on NASA’s $915 million Soil Moisture Active Passive (SMAP) spacecraft remains out of action more than a month after abruptly switching off, but engineers believe they are getting closer to diagnosing the problem.
Engineers believe SMAP’s radar sensor cut out July 7 because of a yet-undiagnosed issue with the low-voltage power supply on its high-power amplifier, according to an Aug. 5 update from the Jet Propulsion Laboratory, which is leading the mission. The amplifier boosts the power of the radar, which bounces radio signals of the surface of the Earth to derive information including moisture levels in the soil.
JPL has not said exactly went wrong, but the center has winnowed the field of possible problems down to “several candidate faults within the low-voltage power supply,” according to the post.
“Continued analysis and ground testing will be performed over the next several weeks,” JPL wrote. “The next attempt to power up the radar may occur in late August.”
SMAP was launched Jan. 31 and into a circular near-polar orbit with an altitude of 685 kilometers. The spacecraft’s radar antenna features a unique, 6-meter diameter deployable mesh reflector supplied by Northrop Grumman’s Astro Aerospace division.
The SMAP satellite combines measurements from the radar with readings from a more-accurate but lower-resolution radiometer built by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, to measure global soil moisture to a depth of about 5 centimeters. SMAP generates a new global map every three days.
The radiometer is still working, and, other than the balky radar, the spacecraft itself is functioning nominally, JPL wrote.
JPL built and operates SMAP. Goddard is responsible for collecting, processing and distributing the data the spacecraft collects. The mission was one of the Earth Science community’s top priorities in the decadal survey published by the National Academies in 2007 and titled: “Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond.”
One-half of the instrument payload aboard NASA’s $916 million Soil Moisture Active Passive satellite has failed after collecting just two months of data, NASA announced Wednesday after weeks of troubleshooting turned up no progress in recovering the sensor.
Такой рефлектор загубили.
Если это не «Козерог 1», то может быть, сделают копию передатчика с облучателем и на клипсе повесят к неработающему облучателю рядом? И надо придумать как запитать и отключить не работающий. Рефлектор все равно качается – будет проходить фокусом и этот участок.
Опять же «Союз» закажут для спасения.
Scientists Hopeful of Salvaging SMAP Following Loss of Radar by Dan Leone — September 25, 2015
Software tweaks and aid fr om other satellites might help NASA's Soil Moisture Active Passive (SMAP) mission gather at least some of the data it was designed to get, despite the loss of its primary radar. Credit: NASA
WASHINGTON — Despite the July failure of the radar on NASA’s Soil Moisture Active Passive (SMAP) satellite, scientists hope to salvage the $1 billion mission by enhancing data from its other sensor and perhaps by coordinating its measurements with those taken by other spacecraft.
NASA officials acknowledged shortly after abandoning efforts to save the high-resolution radar that its loss means the mission cannot meet the scientific objectives that drove its design. But SMAP’s other sensor, a passive radiometer that measures temperatures on Earth’s surface, can do more than previously thought, and the spacecraft remains healthy, scientists say.
“It is hard to deny that the end of the radar operation is a big deal, but it is certainly not the end of the mission and it does not at all mean the loss of mission science,” Mahta Moghaddam, a professor in the Department of Electrical Engineering at the University of Southern California and a member of the SMAP science team, wrote in a Sept. 23 email.
The combined measurements of SMAP’s radar and radiometer were supposed to yield high-accuracy global maps of soil moisture levels at spatial resolutions of 9 kilometers, and soil freeze/thaw-state maps at 3-kilometer resolution. These measurements, endorsed by the National Research Council as a top NASA priority, were expected to increase scientists’ understanding of climate change processes including the carbon cycle.
SMAP’s radiometer provides more-accurate moisture measurements than the radar but its spatial resolution, at 40 kilometers, is much lower. Moreover, scientists expected to rely almost exclusively on the active, ground-penetrating radar for the freeze/thaw-state measurements.
But NASA has been working on tweaks to the algorithms — step-by-step instructions for software — that process SMAP radiometer data in hopes of replicating the freeze/thaw-state product the radar would have produced.
“The radiometer now literally can save the mission,” Steven Running, a professor at the Department of Ecosystem and Conservation Sciences at the University of Montana in Missoula, wrote in a Sept. 23 email. He nonetheless acknowledged that “some loss of accuracy” is to be expected in a radiometer-only freeze/thaw product because “the passive radiometer is receiving emissions effectively from the surface only,” whereas the radar would have made measurements a few centimeters deep into the soil.
Although software fixes provide some relief, the only sure way to replace the lost SMAP L-band radar data would be with radar data gathered by other satellites, Moghaddam said. There, options are limited.
Data from the L-band radar on the Japanese Aerospace Exploration Agency’s Daichi-2 satellite, which launched in May 2014, are a prime candidate to replace SMAP radar images, but “the data policy is restrictive; continuous and/or global data sets are not accessible to us here in the U.S.,” Moghaddam said.
The C-band radar on Europe’s Sentinel-1A, which launched in April 2014, could also fill in for SMAP’s failed radar. Sentinel-1A “has an open data policy for the most part, and save for its reduced sensitivity to soil moisture under vegetation, it may possibly be used to remedy some of the SMAP radar loss,” Moghaddam said.
While hopeful of meeting at least some of SMAP’s scientific objectives, Running said there are some investigations that simply will not be possible following the loss of the radar, which NASA has attributed to a low-voltage power supply to the sensor’s high-power amplifier.
“There were plans to explore how well the L-band radar could measure vegetation structure, such as forest density, which are now lost,” said Running, who is also chairman of the NASA Advisory Council’s Earth Science subcommittee. “Also some exploration of detecting seasonal changes in canopy water content with an active L-band retrieval was going to be new, but is now not possible.”
Meanwhile, separate investigations into the radar failure are ongoing at NASA Headquarters here, and at the Jet Propulsion Laboratory in Pasadena, California, wh ere SMAP and its radar were designed and built.
Tina Panontin, chief engineer at NASA’s Ames Research Center in Mountain View, California, is in charge of the headquarters-led review team, which is expected to complete its work and issue a report before the end of the year, NASA spokesman Stephen Cole wrote in a Sept. 25 email.
Since announcing the radar’s failure, NASA has shed no new light on its cause other than to say the components involved were based on designs that have flown before, albeit not in the SMAP configuration.
Michael Freilich, director of NASA’s Earth Science Division, said in late July — after the radar stopped working but before NASA gave up on fixing it — that the agency made a conscious decision not to build redundancy into the components.
In a July 27 presentation to the NASA Advisory Council’s science committee, Freilich said JPL engineers decided against a redundant high-power amplifier because “the additional complexity of putting in switches to make it redundant would actually decrease the overall reliability of the instrument.”