Just thought I'd end this month by sharing pictures I took during a public tour, held on July 17, at NASA's Jet Propulsion Laboratory (JPL) in La Cañada Flintridge, California.
Unlike previous tours that I attended over the past couple of years, there was no spacecraft like Europa Clipper or the Perseverance Mars rover currently being built inside JPL's historic Spacecraft Assembly Facility. Instead, a science instrument known as ASTHROS(Astrophysics Stratospheric Telescope for High Spectral Resolution Observations at Submillimeter-wavelengths) was being prepped for an upcoming high-altitude balloon mission that will deploy above Antarctica. The balloon that will send ASTHROS 130,000 feet (25 miles) into the stratosphere itself is pretty impressive; when fully-inflated, the helium-filled sphere will reach a diameter of 460 feet, which is about the size of Dodger Stadium here in Los Angeles!
While it's cool to see an airborne science instrument being constructed at JPL, it remains to be seen when the venerable laboratory will get to assemble a spaceborne payload (for a mission like Mars Sample Return) once again. Thanks to the loss of hundreds of laid-off employees and an uncertain NASA budget for next year thanks to Donald Trump, it may be quite a while till JPL gets to construct another robotic explorer that will venture somewhere in our Solar System.
In the meantime, JPL will just have to remain the "Center of the Universe" for current deep space missions that won't be affected by the lousy policies of a convicted felon in the White House. Carry on.
NASA’s Deep Space Network Starts New Dish, Marks 60 Years in Australia (News Release - April 8)
Canberra joined the global network in 1965 and operates four radio antennas. Now, preparations have begun on its fifth as NASA works to increase the network’s capacity.
NASA’s Deep Space Network facility in Canberra, Australia, celebrated its 60th anniversary on March 19 while also breaking ground on a new radio antenna. The pair of achievements are major milestones for the network, which communicates with spacecraft all over the Solar System using giant dish antennas located at three complexes around the globe.
Canberra’s newest addition, Deep Space Station 33, will be a 112-foot-wide (34-meter-wide) multifrequency beam-waveguide antenna. Buried mostly below ground, a massive concrete pedestal will house cutting-edge electronics and receivers in a climate-controlled room and provide a sturdy base for the reflector dish, which will rotate during operations on a steel platform called an alidade.
“As we look back on 60 years of incredible accomplishments at Canberra, the groundbreaking of a new antenna is a symbol for the next 60 years of scientific discovery,” said Kevin Coggins, deputy associate administrator of NASA’s SCaN (Space Communications and Navigation) Program at NASA Headquarters in Washington. “Building cutting-edge antennas is also a symbol of how the Deep Space Network embraces new technologies to enable the exploration of a growing fleet of space missions.”
When it goes online in 2029, the new Canberra dish will be the last of six parabolic dishes constructed under NASA’s Deep Space Network Aperture Enhancement Program, which is helping to support current and future spacecraft and the increased volume of data they provide. The network’s Madrid facility christened a new dish in 2022, and the Goldstone, California, facility is putting the finishing touches on a new antenna.
Canberra’s Role
The Deep Space Network was officially founded on December 24, 1963, when NASA’s early ground stations, including Goldstone, were connected to the new network control center at the agency’s Jet Propulsion Laboratory in Southern California. Called the Space Flight Operations Facility, that building remains the center through which data from the three global complexes flows.
The Madrid facility joined in 1964, and Canberra went online in 1965, going on to help support hundreds of missions, including the Apollo Moon landings.
“Canberra has played a crucial part in tracking, communicating and collecting data from some of the most momentous missions in space history,” said Kevin Ferguson, director of the Canberra Deep Space Communication Complex. “As the network continues to advance and grow, Canberra will continue to play a key role in supporting humanity’s exploration of the cosmos.”
By being spaced equidistant from one another around the globe, the complexes can provide continual coverage of spacecraft, no matter where they are in the Solar System as Earth rotates. There is an exception, however: Due to Canberra’s location in the Southern Hemisphere, it is the only one that can send commands to, and receive data from, Voyager 2 as it heads south almost 13 billion miles (21 billion kilometers) through interstellar space. More than 15 billion miles (24 billion kilometers) away, Voyager 1 sends its data down to the Madrid and Goldstone complexes, but it, too, can only receive commands via Canberra.
New Technologies
In addition to constructing more antennas like Canberra’s Deep Space Station 33, NASA is looking to the future by also experimenting with laser, or optical, communications to enable significantly more data to flow to and from Earth. The Deep Space Network currently relies on radio frequencies to communicate, but laser operates at a higher frequency, allowing more data to be transmitted.
As part of that effort, NASA is flying the laser-based Deep Space Optical Communications experiment with the agency’s Psyche mission. Since the October 2023 launch, it has demonstrated high-data rates over record-breaking distances and downlinked ultra-high definition streaming video from deep space.
“These new technologies have the potential to boost the science and exploration returns of missions traveling throughout the Solar System,” said Amy Smith, deputy project manager for the Deep Space Network at JPL, which manages the network. “Laser and radio communications could even be combined to build hybrid antennas, or dishes that can communicate using both radio and optical frequencies at the same time. That could be a game changer for NASA.”
Liftoff! NASA’s Europa Clipper Sails Toward Ocean Moon of Jupiter (Press Release)
NASA’s Europa Clipper has embarked on its long voyage to Jupiter, where it will investigate Europa, a moon with an enormous subsurface ocean that may have conditions to support life. The spacecraft launched at 12:06 p.m. EDT on Monday aboard a SpaceX Falcon Heavy rocket from Launch Complex 39A at NASA’s Kennedy Space Center in Florida.
The largest spacecraft that NASA has ever built for a mission headed to another planet, Europa Clipper is also the first NASA mission dedicated to studying an ocean world beyond Earth. The spacecraft will travel 1.8 billion miles (2.9 billion kilometers) on a trajectory that will leverage the power of gravity assists, first to Mars in four months and then back to Earth for another gravity assist flyby in 2026. After it begins orbiting Jupiter in April 2030, the spacecraft will fly past Europa 49 times.
“Congratulations to our Europa Clipper team for beginning the first journey to an ocean world beyond Earth,” said NASA Administrator Bill Nelson. “NASA leads the world in exploration and discovery, and the Europa Clipper mission is no different. By exploring the unknown, Europa Clipper will help us better understand whether there is the potential for life not just within our Solar System, but among the billions of moons and planets beyond our Sun.”
Approximately five minutes after liftoff, the rocket’s second stage fired up and the payload fairing, or the rocket’s nose cone, opened to reveal Europa Clipper. About an hour after launch, the spacecraft separated from the rocket. Ground controllers received a signal soon after, and two-way communication was established at 1:13 p.m. with NASA’s Deep Space Network facility in Canberra, Australia.
Mission teams celebrated as initial telemetry reports showed that Europa Clipper is in good health and operating as expected.
“We could not be more excited for the incredible and unprecedented science NASA’s Europa Clipper mission will deliver in the generations to come,” said Nicky Fox, associate administrator, Science Mission Directorate at NASA Headquarters in Washington. “Everything in NASA science is interconnected, and Europa Clipper’s scientific discoveries will build upon the legacy that our other missions exploring Jupiter — including Juno, Galileo and Voyager — created in our search for habitable worlds beyond our home planet.”
The main goal of the mission is to determine whether Europa has conditions that could support life. Europa is about the size of our own Moon, but its interior is different. Information from NASA’s Galileo mission in the 1990s showed strong evidence that under Europa’s ice lies an enormous, salty ocean with more water than all of Earth’s oceans combined.
Scientists have also found evidence that Europa may host organic compounds and energy sources under its surface. If the mission determines that Europa is habitable, it may mean there are more habitable worlds in our Solar System and beyond than imagined.
“We’re ecstatic to send Europa Clipper on its way to explore a potentially habitable ocean world, thanks to our colleagues and partners who’ve worked so hard to get us to this day,” said Laurie Leshin, director, NASA’s Jet Propulsion Laboratory in Southern California. “Europa Clipper will undoubtedly deliver mind-blowing science. While always bittersweet to send something we’ve labored over for years off on its long journey, we know this remarkable team and spacecraft will expand our knowledge of our Solar System and inspire future exploration.”
In 2031, the spacecraft will begin conducting its science-dedicated flybys of Europa. Coming as close as 16 miles (25 kilometers) to the surface, Europa Clipper is equipped with nine science instruments and a gravity experiment, including an ice-penetrating radar, cameras and a thermal instrument to look for areas of warmer ice and any recent eruptions of water. As the most sophisticated suite of science instruments that NASA has ever sent to Jupiter, they will work in concert to learn more about the moon’s icy shell, thin atmosphere and deep interior.
To power those instruments in the faint sunlight that reaches Jupiter, Europa Clipper also carries the largest solar arrays NASA has ever used for an interplanetary mission. With arrays extended, the spacecraft spans 100 feet (30.5 meters) from end to end. With propellant loaded, it weighs about 13,000 pounds (5,900 kilograms).
In all, more than 4,000 people have contributed to the Europa Clipper mission since it was formally approved in 2015.
“As Europa Clipper embarks on its journey, I’ll be thinking about the countless hours of dedication, innovation and teamwork that made this moment possible,” said Jordan Evans, project manager at NASA JPL. “This launch isn’t just the next chapter in our exploration of the Solar System; it’s a leap toward uncovering the mysteries of another ocean world, driven by our shared curiosity and continued search to answer the question, ‘are we alone?’”
Media Get Close-Up of NASA’s Jupiter-Bound Europa Clipper (News Release)
Excitement is mounting as the largest spacecraft that NASA has ever built for a planetary mission gets readied for an October launch.
Engineers at NASA’s Jet Propulsion Laboratory in Southern California are running final tests and preparing the agency’s Europa Clipper spacecraft for the next leg of its journey: launching from NASA’s Kennedy Space Center in Florida. Europa Clipper, which will orbit Jupiter and focus on the planet’s ice-encased moon Europa, is expected to leave JPL later this spring.
Europa Clipper's launch period opens on October 10.
Members of the media put on “bunny suits” — outfits to protect the massive spacecraft from contamination — to see Europa Clipper up close in JPL’s historic Spacecraft Assembly Facility on Thursday, April 11. Project Manager Jordan Evans, Launch-to-Mars Mission Manager Tracy Drain, Project Staff Scientist Samuel Howell, and Assembly, Test and Launch Operations Cable Harness Engineer Luis Aguila were on the clean room floor, while Deputy Project Manager Tim Larson and Mission Designer Ricardo Restrepo were in the gallery above to explain the mission and its goals.
Planning of the mission began in 2013, and Europa Clipper was officially confirmed by NASA as a mission in 2019. The trip to Jupiter is expected to take about six years, with flybys of Mars and Earth.
Reaching the gas giant in 2030, the spacecraft will orbit Jupiter while flying by Europa dozens of times, dipping as close as 16 miles (25 kilometers) from the moon’s surface to gather data with its powerful suite of science instruments. The information will help scientists learn about the ocean beneath the moon’s icy shell, map Europa’s surface composition and geology, and hunt for any potential plumes of water vapor that may be venting from the crust.
“After over a decade of hard work and problem-solving, we’re so proud to show the nearly-complete Europa Clipper spacecraft to the world,” said Evans. “As critical components came in from institutions across the globe, it’s been exciting to see parts become a greater whole. We can’t wait to get this spacecraft to the Jupiter system.”
At the event, a cutaway model showing the moon’s layers and a globe of the moon helped journalists learn why Europa is such an interesting object of study. On hand with the details were Project Staff Scientist and Assistant Science Systems Engineer Kate Craft from the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland, and, from JPL, Project Scientist Robert Pappalardo, Deputy Project Scientist Bonnie Buratti and Science Communications Lead Cynthia Phillips.
Beyond Earth, Europa is considered one of the most promising potentially-habitable environments in our solar system. While Europa Clipper is not a life-detection mission, its primary science goal is to determine whether there are places below the moon’s icy surface that could support life.
When the main part of the spacecraft arrives at Kennedy Space Center in a few months, engineers will finish preparing Europa Clipper for launch on a SpaceX Falcon Heavy rocket, attaching its giant solar arrays and carefully tucking the spacecraft inside the capsule that rides on top of the rocket. Then Europa Clipper will be ready to begin its space odyssey.
Earlier today, I drove down to NASA's Jet Propulsion Laboratory (JPL) near Pasadena, California, to pay another visit to its Jupiter-bound Europa Clipper spacecraft!
This was my second JPL tour in three months—with the main difference being that Europa Clipper now has its 10-foot-diameter (3-meter-diameter) high-gain antenna installed. Also, there weren't any technicians inside the clean room today...as mission team members were in a separate room testing the spacecraft's electrical systems from their computer workstations.
Eventually, Europa Clipper will leave the clean room to undergo environmental testing such as acoustic testing and a thermal vacuum test inside a special chamber at another location on the JPL campus.
Europa Clipper still has ways to go before it is shipped to NASA's Kennedy Space Center in Florida (courtesy of a U.S. Air Force C-17 aircraft) for an October 2024 launch. Europa Clipper should be sent to Cape Canaveral by next July at the latest.
NASA’s Europa Probe Gets a Hotline to Earth (News Release)
The addition of a high-gain antenna will enable the agency’s Europa Clipper spacecraft – set to launch in October 2024 – to communicate with mission controllers hundreds of millions of miles away.
NASA’s Europa Clipper is designed to seek out conditions suitable for life on an ice-covered moon of Jupiter. On August 14, the spacecraft received a piece of hardware central to that quest: the massive dish-shaped high-gain antenna.
Stretching 10 feet (3 meters) across the spacecraft’s body, the high-gain antenna is the largest and most prominent of a suite of antennas on Europa Clipper. The spacecraft will need it as it investigates the ice-cloaked moon that it’s named after, Europa, some 444 million miles (715 million kilometers) from Earth.
A major mission goal is to learn more about the moon’s subsurface ocean, which might harbor a habitable environment.
Once the spacecraft reaches Jupiter, the antenna’s radio beam will be narrowly directed toward Earth. Creating that narrow, concentrated beam is what high-gain antennas are all about.
The name refers to the antenna’s ability to focus power, allowing the spacecraft to transmit high-powered signals back to NASA’s Deep Space Network on Earth. That will mean a torrent of science data at a high rate of transmission.
The precision-engineered dish was attached to the spacecraft in carefully choreographed stages over the course of several hours inside a Spacecraft Assembly Facility bay at NASA’s Jet Propulsion Laboratory in Southern California. “The antenna has successfully completed all of its stand-alone testing,” said Matthew Bray a few days before the antenna was installed. “As the spacecraft completes its final testing, radio signals will be looped back through the antenna via a special cap, verifying that the telecom signal paths are functional.”
Based at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, Bray is the designer and lead engineer for the high-gain antenna, which he began working on in 2014. It’s been quite a journey for Bray, and for the antenna.
Just over the past year, he’s seen the antenna crisscross the country in the lead-up to the installation. Its ability to beam data precisely was tested twice in 2022 at NASA’s Langley Research Center in Hampton, Virginia.
Between those two visits, the antenna made a stop at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, for vibration and thermal vacuum testing to see if it could handle the shaking of launch and the extreme temperatures of outer space.
Then it was on to JPL in October 2022 for installation on the spacecraft in preparation for shipment next year to NASA’s Kennedy Space Center in Florida.
The long journey to Jupiter begins with launch from Kennedy in October 2024.
Europa in Their Sights
“The high-gain antenna is a critical piece in the buildup of Europa Clipper,” said Jordan Evans, the Clipper project manager at JPL. “It represents a very visible piece of hardware that provides the capability that the spacecraft needs to send the science data back from Europa. Not only does it look like a spacecraft now that it has the big antenna, but it’s ready for its upcoming critical tests as we progress towards launch.”
The spacecraft will train nine science instruments on Europa, all producing large amounts of rich data: high-resolution color and stereo images to study its geology and surface; thermal images in infrared light to find warmer areas where water could be near the surface; reflected infrared light to map ices, salts and organics; and ultraviolet light readings to help determine the makeup of atmospheric gases and surface materials.
Clipper will bounce ice-penetrating radar beams off the subsurface ocean to determine its depth, as well as the thickness of the ice crust above it. A magnetometer will measure the moon’s magnetic field to confirm the deep ocean’s existence and thickness of the ice.
The high-gain antenna will stream most of that data back to Earth over the course of 33 to 52 minutes. The strength of the signal and amount of data it can send at one time will be far greater than that of NASA’s Galileo probe, which ended its eight-year Jupiter mission in 2003.
On site at JPL for the antenna installation was Simmie Berman, the radio frequency module manager at APL. Like Bray, she began her work on the antenna in 2014.
The radio frequency module includes the spacecraft’s entire telecommunications subsystem and a total of seven antennas, the high-gain among them. Berman's job during installation was to ensure the antenna was properly mounted to the spacecraft and that the components are correctly oriented and well integrated.
While the engineers at both APL and JPL have practiced the installation many times, virtually and with real-world mock-ups, August 14 was the first time the high-gain antenna was attached to the spacecraft.
“I’ve never worked on anything of this magnitude, in terms of physical size and also in terms of just general interest,” she said. “Little kids know where Jupiter is. They know what Europa looks like. It’s supercool to get to work on something that has the potential for such a big impact, in terms of knowledge, for humanity.”
After completing this major milestone, Europa Clipper still has a few more steps and a few more tests ahead as it’s prepared for its trip to the outer solar system.
NASA Mars Ascent Vehicle Continues Progress Toward Mars Sample Return (News Release - July 31)
The first rocket launch from the surface of another planet will be accomplished using two solid rocket motors.
NASA’s Mars Ascent Vehicle(MAV) recently reached some major milestones in support of the Mars Sample Return program. The Mars Ascent Vehicle would be the first launch of a rocket from the surface of another planet.
The team developing MAV conducted successful tests of the first and second stage solid rocket motors needed for the launch.
Mars Sample Return will bring scientifically-selected samples to Earth for study using the most sophisticated instrumentation around the world. This strategic partnership with ESA (European Space Agency) features the first mission to return samples from another planet.
The samples currently being collected by NASA’s Perseverance Rover during its exploration of an ancient river delta have the potential to reveal the early evolution of Mars, including the potential for ancient life.
Managed at NASA’s Marshall Space Flight Center in Huntsville, Alabama, MAV is currently set to launch in June 2028, with the samples set to arrive on Earth in the early 2030s. The Mars Sample Return Program is managed by NASA’s Jet Propulsion Laboratory in Southern California.
For the MAV to be successful, the team performs extensive testing, analysis and review of MAV’s design and components. The vehicle will travel aboard the Sample Retrieval Lander during launch from Earth, a two-year journey to Mars, and nearly a year of receiving samples collected by Perseverance.
After the Sample Transfer Arm on the lander loads the samples from Perseverance into a sample container in the nose of the rocket, the MAV will launch from Mars into orbit around the planet, releasing the sample container for the Earth Return Orbiter to capture.
The MAV launch will be accomplished using two solid rocket motors – SRM1 and SRM2. SRM1 will propel MAV away from the Red Planet’s surface, while SRM2 will spin MAV’s second stage to place the sample container in the correct Mars orbit, allowing the Earth Return Orbiter to find it.
To test the solid rocket motor designs, the MAV team prepared development motors. This allowed the team to see how the motors will perform and if any adjustments should be made before they are built for the mission.
The SRM2 development motor was tested on March 29, 2023, at the Northrop Grumman facility in Elkton, Maryland. Then, SRM1’s development motor was tested on April 7 at Edwards Air Force Base in California.
SRM1’s test was conducted in a vacuum chamber that was cooled to -20° Celsius (-4° Fahrenheit) and allowed the team to also test a supersonic splitline nozzle, part of SRM1’s thrust vector control system. Most gimballing solid rocket motor nozzles are designed in a way that can’t handle the extreme cold MAV will experience, so the Northrop Grumman team had to come up with something that could: a state-of-the-art trapped ball nozzle featuring a supersonic split line.
After testing and disassembling the SRM1 development motor, analysis showed that the team’s ingenuity proved successful.
“This test demonstrates our nation has the capacity to develop a launch vehicle that can successfully be lightweight enough to get to Mars and robust enough to put a set of samples into orbit to bring back to Earth,” said MAV Propulsion Manager Benjamin Davis at NASA’s Marshall Space Flight Center. “The hardware is telling us that our technology is ready to proceed with development.”
In fact, the supersonic splitline nozzle has achieved the sixth of nine technology readiness levels – known as TRL-6 – developed by NASA. TRL-1 is the starting point at which there is just an idea for a new technology, while TRL-9 means the technology has been developed, tested and successfully used for an in-space mission.
Davis said the supersonic splitline nozzle achieved TRL-6 through vacuum bench testing and full-scale hot fire testing in April. Results are being independently evaluated and will be confirmed in August.
The supersonic splitline nozzle will also undergo qualification testing to make sure that it can handle the intense shaking and vibration of launch, the near vacuum of space, and the extreme heat and cold expected during MAV’s trip.
Yesterday, I marked the 54th anniversary of the Apollo 11 Moon landing by attending a tour at NASA's Jet Propulsion Laboratory...which I haven't visited since before the pandemic in early 2019!
The main reason why I went to JPL this time around was to see the Europa Clipper in person. Technicians inside the Spacecraft Assembly Facility are working around the clock to get this robotic probe completed as soon and efficiently as possible.
You can watch the technicians work on Europa Clipper via this live webcam! The unmanned explorer will launch on a six-year journey to Jupiter in October of 2024—courtesy of SpaceX's Falcon Heavy rocket.
It was also great visiting the Space Flight Operations Facility again...as well as seeing full-size replicas of the Perseverance Mars rover, the Ingenuity Mars helicopter and the Mars Ascent Vehicle(MAV) that may or may not send rock samples to an orbiting Martian spacecraft for return back to Earth. Read this latest article about the Mars Sample Return mission to know why I'm not so optimistic about the MAV becoming a reality.
The Europa Clipper should be transported to Cape Canaveral in Florida between May and July of next year to be prepped for launch to Jupiter. I plan on seeing this spacecraft in person one last time before it leaves Southern California...
Whether or not this will be through another tour or the JPL open house (a.k.a. Explore JPL) itself remains to be seen! Happy Friday.
Just thought I'd end this month with these photos that I took during a tour I attended at NASA's Jet Propulsion Laboratory (JPL) near Pasadena, California yesterday. The pics above and below are of the 'Skycrane' descent stage that will be used to gently lower the Mars 2020 rover onto the surface of the Red Planet—just like Curiosity before her almost six years ago—in February of 2021 (the rover will launch from Cape Canaveral Air Force Station in Florida in the summer of 2020). Towards the right of the image directly below, you'll see the circular cruise stage for Mars 2020 also undergoing construction inside JPL's Spacecraft Assembly Facility (SAF). The rover itself will begin official assembly inside the SAF later this year. And of course, I couldn't overlook the obligatory snapshots that I took inside the historic Space Flight Operations Facility, as well as the full-size replica of the Voyager spacecraft in the Von Kármán Auditorium.
Three of these pics were taken with my Nikon D3300 DSLR camera. Guess which ones? Happy Thursday!
A United Launch Alliance Delta II rocket with the Soil Moisture Active Passive(SMAP) observatory onboard is seen in this long exposure photograph as it launches from Space Launch Complex 2, Saturday, Jan. 31, 2015, Vandenberg Air Force Base, Calif. SMAP is NASA’s first Earth-observing satellite designed to collect global observations of surface soil moisture and its freeze/thaw state. SMAP will provide high resolution global measurements of soil moisture from space. The data will be used to enhance scientists' understanding of the processes that link Earth's water, energy, and carbon cycles.
NASA Satellite Set to Get the Dirt on Soil Moisture (Press Release)
A new NASA satellite that will peer into the topmost layer of Earth's soils to measure the hidden waters that influence our weather and climate is in final preparations for a Jan. 29 dawn launch from California.
The Soil Moisture Active Passive(SMAP) mission will take the pulse of a key measure of our water planet: how freshwater cycles over Earth's land surfaces in the form of soil moisture. The mission will produce the most accurate, highest-resolution global maps ever obtained from space of the moisture present in the top 2 inches (5 centimeters) of Earth's soils. It also will detect and map whether the ground is frozen or thawed. This data will be used to enhance scientists' understanding of the processes that link Earth's water, energy and carbon cycles.
"With data from SMAP, scientists and decision makers around the world will be better equipped to understand how Earth works as a system and how soil moisture impacts a myriad of human activities, from floods and drought to weather and crop yield forecasts," said Christine Bonniksen, SMAP program executive with the Science Mission Directorate's Earth Science Division at NASA Headquarters in Washington. "SMAP's global soil moisture measurements will provide a new capability to improve our understanding of Earth's climate."
Globally, the volume of soil moisture varies between three and five percent in desert and arid regions, to between 40 and 50 percent in saturated soils. In general, the amount depends on such factors as precipitation patterns, topography, vegetation cover and soil composition. There are not enough sensors in the ground to map the variability in global soil moisture at the level of detail needed by scientists and decision makers. From space, SMAP will produce global maps with 6-mile (10-kilometer) resolution every two to three days.
Researchers want to measure soil moisture and its freeze/thaw state better for numerous reasons. Plants and crops draw water from the soil through their roots to grow. If soil moisture is inadequate, plants fail to grow, which over time can lead to reduced crop yields. Also, energy from the sun evaporates moisture in the soil, thereby cooling surface temperatures and also increasing moisture in the atmosphere, allowing clouds and precipitation to form more readily. In this way, soil moisture has a significant effect on both short-term regional weather and longer-term global climate.
In summer, plants in Earth's northern boreal regions -- the forests found in Earth's high northern latitudes -- take in carbon dioxide from the air and use it to grow, but lay dormant during the winter freeze period. All other factors being equal, the longer the growing season, the more carbon plants take in and the more effective forests are in removing carbon dioxide from the air. Since the start of the growing season is marked by the thawing and refreezing of water in soils, mapping the freeze/thaw state of soils with SMAP will help scientists more accurately account for how much carbon plants are removing from the atmosphere each year. This information will lead to better estimates of the carbon budget in the atmosphere and, hence, better assessments of future global warming.
SMAP data will enhance our confidence in projections of how Earth's water cycle will respond to climate change.
"Assessing future changes in regional water availability is perhaps one of the greatest environmental challenges facing the world today," said Dara Entekhabi, SMAP science team leader at the Massachusetts Institute of Technology in Cambridge. "Today's computer models disagree on how the water cycle -- precipitation, clouds, evaporation, runoff, soil water availability -- will increase or decrease over time and in different regions as our world warms. SMAP's higher-resolution soil moisture data will improve the models used to make daily weather and longer-term climate predictions."
SMAP also will advance our ability to monitor droughts, predict floods and mitigate the related impacts of these extreme events. It will allow the monitoring of regional deficits in soil moisture and provide critical inputs into drought monitoring and early warning systems used by resource managers. The mission's high-resolution observations of soil moisture will improve flood warnings by providing information on ground saturation conditions before rainstorms.
SMAP's two advanced instruments work together to produce soil moisture maps. Its active radar works much like a flash camera, but instead of transmitting visible light, it transmits microwave pulses that pass through clouds and moderate vegetation cover to the ground and measures how much of that signal is reflected back. Its passive radiometer operates like a natural-light camera, capturing emitted microwave radiation without transmitting a pulse. Unlike traditional cameras, however, SMAP's images are in the microwave range of the electromagnetic spectrum, which is invisible to the naked eye. Microwave radiation is sensitive to how much moisture is contained in the soil.
The two instruments share a large, lightweight reflector antenna that will be unfurled in orbit like a blooming flower and then spin at about 14 revolutions per minute. The antenna will allow the instruments to collect data across a 621-mile (1,000-kilometer) swath, enabling global coverage every two to three days.
SMAP's radiometer measurements extend and expand on soil moisture measurements currently made by the European Space Agency's Soil Moisture Ocean Salinity(SMOS) mission, launched in 2009. With the addition of a radar instrument, SMAP's soil moisture measurements will be able to distinguish finer features on the ground.
SMAP will launch from Vandenberg Air Force Base on a United Launch Alliance Delta II rocket and maneuver into a 426-mile (685-kilometer) altitude, near-polar orbit that repeats exactly every eight days. The mission is designed to operate at least three years.
SMAP is managed for NASA's Science Mission Directorate in Washington by the agency’s Jet Propulsion Laboratory (JPL) in Pasadena, California, with instrument hardware and science contributions made by NASA's Goddard Space Flight Center in Greenbelt, Maryland. JPL is responsible for project management, system engineering, radar instrumentation, mission operations and the ground data system. Goddard is responsible for the radiometer instrument. Both centers collaborate on science data processing and delivery to the Alaska Satellite Facility, in Fairbanks, and the National Snow and Ice Data Center, at the University of Colorado in Boulder, for public distribution and archiving. NASA's Launch Services Program at the agency’s Kennedy Space Center in Florida is responsible for launch management. JPL is managed for NASA by the California Institute of Technology in Pasadena.
