Spring on Titan Brings Sunshine and Patchy Clouds

The northern hemisphere of Saturn's moon Titan is set for mainly fine spring weather, with polar skies clearing since the equinox in August last year. The visual and infrared mapping spectrometer (VIMS) aboard NASA's Cassini spacecraft has been monitoring clouds on Titan regularly since the spacecraft entered orbit around Saturn in 2004. Now, a group led by Sébastien Rodriguez, a Cassini VIMS team collaborator based at Université Paris Diderot, France, has analyzed more than 2,000 VIMS images to create the first long-term study of Titan's weather using observational data that also includes the equinox. Equinox, when the sun shone directly over the equator, occurred in August 2009.

Rodriguez is presenting the results and new images at the European Planetary Science Congress in Rome on Sept. 22.

Though Titan's surface is far colder and lacks liquid water, this moon is a kind of "sister world" to Earth because it has a surface covered with organic material and an atmosphere whose chemical composition harkens back to an early Earth. Titan has a hydrological cycle similar to Earth's, though Titan's cycle depends on methane and ethane rather than water.

A season on Titan lasts about seven Earth years. Rodriguez and colleagues observed significant atmospheric changes between July 2004 (early summer in Titan's southern hemisphere) and April 2010 (the very start of northern spring). The images showed that cloud activity has recently decreased near both of Titan's poles. These regions had been heavily overcast during the late southern summer until 2008, a few months before the equinox.

Over the past six years, the scientists found that clouds clustered in three distinct latitude regions of Titan: large clouds at the north pole, patchy clouds at the south pole and a narrow belt around 40 degrees south. "However, we are now seeing evidence of a seasonal circulation turnover on Titan – the clouds at the south pole completely disappeared just before the equinox and the clouds in the north are thinning out," Rodriguez said. "This agrees with predictions from models and we are expecting to see cloud activity reverse from one hemisphere to another in the coming decade as southern winter approaches."

NASA's Magnetospheric Mission Passes Major Milestone

The universe is still an arcane place that scientists know very little about, but a new NASA Solar Terrestrial Probe mission is going to shed light on one especially mysterious event called magnetic reconnection. It occurs when magnetic lines of force cross, cancel, and reconnect releasing magnetic energy in the form of heat and charged-particle kinetic energy.


On the sun, magnetic reconnection causes solar flares more powerful than several atomic bombs combined. In Earth's atmosphere, magnetic reconnection dispenses magnetic storms and auroras, and in laboratories on Earth it can cause big problems in fusion reactors.

Although the study of magnetic reconnection dates back to the 1950s and despite numerous scientific papers addressing this perplexing issue, scientists still cannot agree on one accepted model.

In 2014, NASA is scheduled to launch a satellite that will greatly increase our understanding of this phenomenon when it launches the Magnetospheric Multiscale (MMS) mission, a suite of four identical spacecraft that will study magnetic reconnection in the best possible laboratory – the Earth’s magnetosphere. The spacecraft will obtain measurements necessary to test prevailing theories as to how reconnection is enabled and how it progresses.

Artist conception of the four Magnetospheric Multiscale (MMS) spacecraft investigating magnetic reconnection within Earth's magnetic field (magnetosphere). Credit: Southwest Research Institute

Recently, NASA and members of an independent review board painstakingly reviewed every aspect of the MMS mission, and successfully completed the mission’s critical design review. This technical review is held to ensure that a mission can proceed into fabrication, demonstration and test and can meet stated performance requirements, including cost, schedule, risk and other system constraints.

According to MMS deputy project scientist Mark Adrian of NASA’s Goddard Space Flight Center in Greenbelt, Md., “This is the last hurdle before the spacecraft and instrument teams begin to build actual flight hardware.”

MMS was approved for implementation in June 2009 following a successful Preliminary Design Review in May 2009.

Dr. James L. Burch of the Southwest Research Institute in San Antonio, Texas, will lead the MMS science team. According to Burch, “Magnetic reconnection is a fundamental physical process that occurs throughout the universe,” says Burch. “MMS will enable us to study this dynamic process in the near-Earth space environment, where it transfers energy from the solar wind to the magnetosphere and drives disturbances known as space weather.”

Goddard is the lead Center for the mission. Engineers there will perform the required environmental testing, build the spacecraft and integrate all four sets of instruments into the MMS satellites, support launch vehicle integration and operations, and develop the Mission Operations Center which to monitor and control the spacecraft.

MMS will carry identical suites of plasma analyzers, energetic particle detectors, magnetometers, and electric field instruments as well as a device to prevent spacecraft charging from interfering with the highly sensitive measurements required in and around the diffusion regions.

Scientists and engineers at Goddard have designed and will build one of the instruments – the Fast Plasma Instrument, which will measure the ion and electron distributions and the electric and magnetic fields with unprecedentedly high millisecond time resolution and accuracy.

Currently, MMS is scheduled to launch in August 2014 from Cape Canaveral Air Force Station, FL aboard an Atlas V rocket.

NASA's Avionics Testing: There's More Than One String to This Fiddle

"Having more than one string on a fiddle" is an old phase used to describe someone or something with multiple talents or uses. This expression could be used to describe NASA's avionics string testing -- a developmental testing process that allows engineers to find and fix any bugs in a system by inputting commands and scrutinizing the electronics system’s responses.

NASA and ATK Aerospace Systems of Magna, Utah, prime contractor for the Ares I first stage avionics system, currently are conducting a series of string tests at ATK's test facility in Clearfield, Utah.

So exactly what is an avionics system and how is NASA using string testing to help design the next generation of solid-rocket-motor-based launch systems?

The avionics system is the "brains" for a launch vehicle, consisting of the electronics system, equipment and associated sensors responsible for controlling key guidance, launch, navigation and recovery hardware. The first stage avionics works with the upper stage flight computers and guidance systems to control the vehicle during first stage ascent and executes recovery of the first stage after staging.

During testing, control boxes of the first stage avionics system are wired together in a line -- the so-called string – with multiple strings making up the entire avionics system. The strings are connected to a ground computer which simulates the upper stage flight computer by issuing commands to the appropriate control box, requiring a particular response.


"System level or "string" testing is a widely recognized process that allows our team to locate and identify functional and performance-related problems within the hardware," said Kendall Junen, avionics and control team lead for Ares Projects at NASA's Marshall Space Flight Center in Huntsville, Ala. "It involves taking various system requirements and testing the hardware in controlled laboratory scenarios to determine how well the system performs."

"This laboratory allows us to test like you fly. We can assemble the entire avionics system and put it through precise, flight-like scenarios," he said. "We can test the system's reaction to certain computer-generated anomalies and identify potential performance issues associated with specific hardware."

Next Stop, Titan: Looking at the Land o' Lakes

NASA's Cassini spacecraft will be eyeing the north polar region of Saturn's moon Titan this weekend, scanning the moon's land o' lakes.

At closest approach on early morning Saturday, June 5 UTC, which is Friday afternoon, June 4 Pacific time, Cassini will glide to within about 2,000 kilometers (1,300 miles) of the Titan surface.

Cassini will make infrared scans of the north polar region, which was in darkness for the first several years of Cassini's tour around the Saturn system. The lighting has improved as northern spring has started to dawn over the area.

The visual and infrared spectrometer will be prime during closest approach, but the imaging science subsystem cameras will also be taking pictures. Among the scientific bounties, Cassini team members are hoping to get another good look at Kraken Mare, the largest lake on Titan, which covers a greater area than the Caspian Sea on Earth.

Although this latest flyby is dubbed "T69," planning changes early in the orbital tour made this the 70th targeted flyby of Titan.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL.

WISE Makes Progress on its Space Rock Catalog

NASA's Wide-field Infrared Survey Explorer, or WISE, is busy surveying the landscape of the infrared sky, building up a catalog of cosmic specimens -- everything from distant galaxies to "failed" stars, called brown dwarfs.

Closer to home, the mission is picking out an impressive collection of asteroids and comets, some known and some never seen before. Most of these hang out in the Main Belt between Mars and Jupiter, but a small number are near-Earth objects -- asteroids and comets with orbits that pass within about 48 million kilometers (30 million miles) of Earth's orbit. By studying a small sample of near-Earth objects, WISE will learn more about the population as a whole. How do their sizes differ, and how many objects are dark versus light?

"We are taking a census of a small sample of near-Earth objects to get a better idea of how they vary," said Amy Mainzer, the principal investigator of NEOWISE, a program to catalog asteroids seen with WISE.

So far, the mission has observed more than 60,000 asteroids, both Main Belt and near-Earth objects. Most were known before, but more than 11,000 are new.

"Our data pipeline is bursting with asteroids," said WISE Principal Investigator Ned Wright of UCLA. "We are discovering about a hundred a day, mostly in the Main Belt."

About 190 near-Earth asteroids have been observed to date, of which more than 50 are new discoveries. All asteroid observations are reported to the NASA-funded International Astronomical Union's Minor Planet Center, a clearinghouse for data on all solar system bodies at the Smithsonian Astrophysical Observatory in Cambridge, Mass.

"It's a really exciting time for asteroid science," said Tim Spahr, who directs the Minor Planet Center. "WISE is another tool to add to our tool belt of instruments to discover and study the asteroid population."

A network of ground-based telescopes follows up and confirms the WISE finds, including the NASA-funded University of Arizona Spacewatch and Catalina Sky Survey projects, both near Tucson, Ariz., and the NASA-funded Magdalena Ridge Observatory near Socorro, N.M.

Some of the near-Earth asteroids detected so far are visibly dark, but it's too early to say what percentage. The team needs time to properly analyze and calibrate the data. When results are ready, they will be published in a peer-reviewed journal. WISE has not found an asteroid yet that would be too dark for detection by visible-light telescopes on the ground.

Engineers Diagnosing Voyager 2 Data System

One flip of a bit in the memory of an on board computer appears to have caused the change in the science data pattern returning from Voyager 2, engineers at NASA's Jet Propulsion Laboratory said Monday, May 17. A value in a single memory location was changed from a 0 to a 1.

On May 12, engineers received a full memory readout from the flight data system computer, which formats the data to send back to Earth. They isolated the one bit in the memory that had changed, and they recreated the effect on a computer at JPL. They found the effect agrees with data coming down from the spacecraft. They are planning to reset the bit to its normal state on Wednesday, May 19.

Engineers have shifted NASA's Voyager 2 spacecraft into a mode that transmits only spacecraft health and status data while they diagnose an unexpected change in the pattern of returning data. Preliminary engineering data received on May 1 show the spacecraft is basically healthy, and that the source of the issue is the flight data system, which is responsible for formatting the data to send back to Earth. The change in the data return pattern has prevented mission managers from decoding science data.

The first changes in the return of data packets from Voyager 2, which is near the edge of our solar system, appeared on April 22. Mission team members have been working to troubleshoot and resume the regular flow of science data. Because of a planned roll maneuver and moratorium on sending commands, engineers got their first chance to send commands to the spacecraft on April 30. It takes nearly 13 hours for signals to reach the spacecraft and nearly 13 hours for signals to come down to NASA's Deep Space Network on Earth.

Voyager 2 launched on August 20, 1977, about two weeks before its twin spacecraft, Voyager 1. The two spacecraft are the most distant human-made objects, out at the edge of the heliosphere, the bubble the sun creates around the solar system. Mission managers expect Voyager 1 to leave our solar system and enter interstellar space in the next five years or so, with Voyager 2 on track to enter interstellar space shortly afterward. Voyager 1 is in good health and performing normally.

"Voyager 2's initial mission was a four-year journey to Saturn, but it is still returning data 33 years later," said Ed Stone, Voyager project scientist at the California Institute of Technology in Pasadena. "It has already given us remarkable views of Uranus and Neptune, planets we had never seen close-up before. We will know soon what it will take for it to continue its epic journey of discovery."

The original goals for the two Voyager spacecraft were to explore Jupiter and Saturn.

As part of a mission extension, Voyager 2 also flew by Uranus in 1986 and Neptune in 1989, taking advantage of a once-in-176-year alignment to take a grand tour of the outer planets. Among its many findings, Voyager 2 discovered Neptune's Great Dark Spot and 450-meter-per-second (1,000-mph) winds. It also detected geysers erupting from the pinkish-hued nitrogen ice that forms the polar cap of Neptune's moon Triton. Working in concert with Voyager 1, it also helped discover actively erupting volcanoes on Jupiter's moon Io, and waves and kinks in Saturn's icy rings from the tugs of nearby moons.

Voyager 2 is about 13.8 billion kilometers, or 8.6 billion miles, from Earth. Voyager 1 is about 16.9 billion kilometers (10.5 billion miles) away from Earth.

Cassini Returning Enceladus Gravity Data

NASA's Cassini spacecraft successfully completed its 26-hour gravity observation at Saturn's moon Enceladus this week, sending back data scientists will use to understand the moon's interior composition and structure.

The flyby took Cassini through the water-rich plume flaring out from Enceladus' south polar region, with a closest approach of about 100 kilometers (60 miles) occurring in the late afternoon of April 27, 2010, Pacific Time, or just after midnight April 28 UTC.

A steady radio link to NASA's Deep Space Network on Earth enabled Cassini's scientists to use the radio science instrument to measure the variations in the gravitational pull of Enceladus. Analyzing the wiggles will help scientists understand whether an ocean, pond or great lake lies under the famous "tiger stripe" fractures that spew water vapor and organic particles from the south polar region.

Results from the experiment will also tell scientists if bubbles of warmer ice in the interior rise toward that region's surface like an underground lava lamp.

Radio science was prime during the flyby and controlled spacecraft pointing. The optical instruments were not pointed at Enceladus during most of the flyby, so the imaging camera obtained some more distant pictures.

Cassini often relies on thrusters to control attitude during flybys such as this one, but this time it turned the thrusters off and relied on its reaction wheels. Using thrusters adds acceleration effects to the spacecraft, complicating the precise measurements needed for the radio science experiment.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate in Washington. The Cassini orbiter was designed, developed and assembled at JPL.

IceBridge task at Halfway Point

On April 19, 2010, the IceBridge team flew underneath the clouds in difficult conditions to collect critical data for monitoring changes in sea ice in the Arctic Ocean. Credit: Michael Studinger

The 2010 Operation IceBridge mission to the Arctic is nearing its halfway point and wrapping up flights with NASA's DC-8 research airplane. In just over four weeks since leaving Palmdale, Calif., on March 21, scientists and crew have flown 14 successful missions over the Arctic Ocean and the Greenland Ice Sheet. They have been in the air for more than 120 hours and have flown a distance greater than 1.5 times around the world.

IceBridge project scientist Michael Studinger, from the Goddard Earth Science and Technology Center at the University of Maryland - Baltimore County, wrote from Thule, Greenland, to discuss some of the mission's accomplishments and critical moments, including one important flight that was almost thwarted by the Arctic weather.

NASA's New Eye on the Sun bring eye-catching First Images

NASA's recently launched Solar Dynamics Observatory, or SDO, is returning early images that confirm an unprecedented new capability for scientists to better understand our sun’s dynamic processes. These solar activities affect everything on Earth.

Some of the images from the spacecraft show never-before-seen detail of material streaming outward and away from sunspots. Others show extreme close-ups of activity on the sun’s surface. The spacecraft also has made the first high-resolution measurements of solar flares in a broad range of extreme ultraviolet wavelengths.

"These initial images show a dynamic sun that I had never seen in more than 40 years of solar research,” said Richard Fisher, director of the Heliophysics Division at NASA Headquarters in Washington. "SDO will change our understanding of the sun and its processes, which affect our lives and society. This mission will have a huge impact on science, similar to the impact of the Hubble Space Telescope on modern astrophysics.”



SDO will send 1.5 terabytes of data back to Earth each day, which is equivalent to a daily download of half a million songs onto an MP3 player. The observatory carries three state-of the-art instruments for conducting solar research.

The Helioseismic and Magnetic Imager maps solar magnetic fields and looks beneath the sun’s opaque surface. The experiment will decipher the physics of the sun’s activity, taking pictures in several very narrow bands of visible light. Scientists will be able to make ultrasound images of the sun and study active regions in a way similar to watching sand shift in a desert dune. The instrument’s principal investigator is Phil Scherrer of Stanford University. HMI was built by a collaboration of Stanford University and the Lockheed Martin Solar and Astrophysics Laboratory in Palo Alto, Calif.

The Atmospheric Imaging Assembly is a group of four telescopes designed to photograph the sun’s surface and atmosphere. The instrument covers 10 different wavelength bands, or colors, selected to reveal key aspects of solar activity. These types of images will show details never seen before by scientists. The principal investigator is Alan Title of the Lockheed Martin Solar and Astrophysics Laboratory, which built the instrument.

The Extreme Ultraviolet Variability Experiment measures fluctuations in the sun’s radiant emissions. These emissions have a direct and powerful effect on Earth’s upper atmosphere -- heating it, puffing it up, and breaking apart atoms and molecules. Researchers don’t know how fast the sun can vary at many of these wavelengths, so they expect to make discoveries about flare events. The principal investigator is Tom Woods of the Laboratory for Atmospheric and Space Physics at the University of Colorado, Boulder. LASP built the instrument.

"These amazing images, which show our dynamic sun in a new level of detail, are only the beginning of SDO's contribution to our understanding of the sun," said SDO Project Scientist Dean Pesnell of Goddard.

SDO is the first mission of NASA's Living with a Star Program, or LWS, and the crown jewel in a fleet of NASA missions that study our sun and space environment. The goal of LWS is to develop the scientific understanding necessary to address those aspects of the connected sun-Earth system that directly affect our lives and society.

Students Send Balloons to the Stratosphere

How different does the world look from 100,000 feet in the air? How do cities and suburbs, fields and forests appear when viewed from a vantage point of nearly twenty miles above Earth's surface?

Through an innovative program at NASA's Glenn Research Center in Cleveland, local high school students have the opportunity to make these discoveries firsthand while learning practical math, science and engineering skills. Participants in the BalloonSAT Exploring Program launch a 6-foot diameter weather balloon, complete with experiments and cameras, into the space-like regions of Earth's upper atmosphere.

Exploring with Balloons

The Exploring Program is affiliated with the Boy Scouts of America. This program is designed to give high school students opportunities to experience different potential careers. Throughout the country, students in the Exploring Program learn from various professionals -- like firemen, police officers and medical workers -- about the skills necessary for these jobs. At Glenn, students explore what it's like to be a scientist or engineer in one of four Exploring Posts: Aeronautics, Computer, Human Space Exploration and BalloonSAT. Stephanie Brown-Houston, from the Glenn Educational Program, is the program manager for the Exploring Program → at Glenn.

The use of weather balloons as satellites (BalloonSAT) first began at Glenn a decade ago as a way of investigating solar cell calibration in space. A small payload which tracked the sun was suspended by a weather balloon and flown to gather data. The balloon served as an inexpensive high-altitude launch system.

The BalloonSAT Exploring Post 632 began in 2004. Dr. David Snyder, a physicist and electrical engineer in the Photovoltaic and Power Technologies branch of the Power & In-Space Propulsion division at Glenn, is the lead advisor for BalloonSAT Exploring Post.

"The overall goal is to give high school kids a chance to explore these professions," Snyder says. "It's about getting them interested in science and space and technology."

Learning by Doing

Each academic year, a group of 10 to 15 high school students join the BalloonSAT Exploring Post. These diverse students, from multiple high schools around the Cleveland area, work together to perform one or two launches every year. When the first launch occurs, it is more of a demonstration launch and takes place early in the program, in the fall. The second launch, which takes place in early spring, is coordinated and executed by the students and features the experiments they designed.

"BalloonSAT attempts to simulate a satellite mission," Snyder says. "We give students the chance to design experiments and fly them with a flight program, and get results."

The students work all year to research, develop, design and fabricate experiments that will be flown when they launch their balloon. In the seven missions that BalloonSAT has flown, dozens of student-designed experiments have been launched 100,000 feet in the air.

Previous experiments have included:
* Exposure experiments with rubber bands, seeds and mold
* Light and temperature sensors
* Aerogel particle capture
* Cosmic ray detection
* Geiger counters
* Electronic compass correlation
* Carbon Dioxide/Ozone detectors
* Solar cell measurements
* Latex balloon expansion
* Yeast growth and carbon dioxide generation

This year's launch, which is schedule for April 24, includes a variety of experiments such as:

* 3-D photography
* Video image transmission
* Chemical hand warmer testing
* Electric field disturbances
* Glass fragility during flight
* Wood glue exposure
* Humidity measurements

The students spend the year preparing for the launch; the multi-faceted project teaches the students numerous skills.

Helicopter Helps Test Radar for 2012 Mars Landing

This spring, engineers are testing a radar system that will serve during the next landing on Mars.

Recent tests included some near Lancaster, Calif., against a backdrop of blooming California poppy fields. In those tests, a helicopter carried an engineering test model of the landing radar for NASA's Mars Science Laboratory on prescribed descent paths. The descents at different angles and from different heights simulated paths associated with specific candidate sites for the mission.

The Mars Science Laboratory mission, managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA, is in its assembly and testing phase, in advance of a launch in autumn 2011 and delivery of a rover named Curiosity to Mars in summer 2012.

During the final stage of the spacecraft's arrival at Mars in 2012, a rocket-powered descent stage will lower the rover on a tether directly to the ground. This rover is too big for the airbag-cushioned landing method used by NASA's Mars Pathfinder mission in 1997 and Mars Exploration Rover landings in 2004.

At Mars, a radar on the descent stage will track the spacecraft's decreasing distance from the surface. Additional helicopter-flown testing of the mission's radar system will include checks of whether the suspended rover might confuse the radar about the speed of descent toward the ground.

NASA-Funded Research Suggests Venus is Geologically Alive

For the first time, scientists have detected clear signs of recent lava flows on the surface of Venus.

The observations reveal that volcanoes on Venus appeared to erupt between a few hundred years to 2.5 million years ago. This suggests the planet may still be geologically active, making Venus one of the few worlds in our solar system that has been volcanically active within the last 3 million years.

The evidence comes from the European Space Agency's Venus Express mission, which has been in orbit around the planet since April 2006. The science results were laid over topographic data from NASA's Magellan spacecraft. Magellan radar-mapped 98 percent of the surface and collected high-resolution gravity data while orbiting Venus from 1990 to 1994.

Scientists see compositional differences compared to the surrounding landscape in three volcanic regions. Relatively young lava flows have been identified by the way they emit infrared radiation. These observations suggest Venus is still capable of volcanic eruptions. The findings appear in the April 8 edition of the journal Science.


"The geological history of Venus has long been a mystery," said Sue Smrekar, a scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., and lead author of the paper describing the work. "Previous spacecraft gave us hints of volcanic activity, but we didn't know how long ago that occurred. Now we have strong evidence right at the surface for recent eruptions."

The volcanic provinces, or hotspots, on which Smrekar and her team focused are geologically similar to Hawaii. Scientists previously detected plumes of hot rising material deep under Venus' surface. Those plumes are thought to have produced significant volcanic eruptions. Other data from the planet suggest that volatile gases commonly spewed from volcanoes were breaking down in its atmosphere. The rate of volcanism will help scientists determine how the interior of the planet works and how gases emitted during eruptions affect climate.

Something is smoothing Venus' surface, because the planet has only about 1,000 craters, a relatively small amount compared to other bodies in our solar system. Scientists think it may be the result of volcanic activity and want to know if it happens quickly or slowly. The Venus Express results suggest a gradual sequence of smaller volcanic eruptions as opposed to a cataclysmic volcanic episode that resurfaces the entire planet with lava.

Smrekar and her team also discovered that several volcanic features in the regions they studied show evidence of minerals found in recent lava flows. These mineral processes correspond to the youngest volcanic flows in each region, giving scientists additional support for the idea they formed during recent volcanic activity. On Earth, lava flows react rapidly with oxygen and other elements in the atmosphere when they erupt to the surface. On Venus, the process is similar, although it is more intense and changes the outer layer more substantially.

Scientists call Venus Earth's sister planet because of similarities in size, mass, density and volume. Scientists deduce that both planets shared a common origin, forming at the same time about 4.5 billion years ago. Venus also is the planet on which the runaway greenhouse effect was discovered. The planet is cloaked in a much less friendly atmosphere than that found on Earth. It is composed chiefly of carbon dioxide, which generates a surface temperature hot enough to melt lead, and a surface pressure 90 times greater than that on Earth.

The small group of worlds in our solar system known to be volcanically active today includes Earth and Jupiter's moon Io. Crater counts on Mars also have suggested recent lava flows. Scientists are studying evidence of another kind of active volcanism that involves ice-spewing volcanoes on other moons in our solar sys

Arctic 2010 Sea Ice Maximum, Visualized

NASA - Sea ice coverage over the Arctic Ocean oscillates over the course of a year, growing through winter and reaching a maximum extent by February or March. This year, Arctic sea ice grew to levels beyond those measured in recent years but slightly below average when compared to the 30-year satellite record.

Cassini Doubleheader- Flying By Titan and Dione

In a special double flyby early next week, NASA's Cassini spacecraft will visit Saturn's moons Titan and Dione within a period of about a day and a half, with no maneuvers in between. A fortuitous cosmic alignment allows Cassini to attempt this doubleheader, and the interest in swinging by Dione influenced the design of its extended mission.

The Titan flyby, planned for Monday, April 5, will take Cassini to within about 7,500 kilometers (4,700 miles) of the moon's surface. The distance is relatively long as far as encounters go, but it works to the advantage of Cassini's imaging science subsystem. Cassini's cameras will be able to stare at Titan's haze-shrouded surface for a longer time and capture high-resolution pictures of the Belet and Senkyo areas, dark regions around the equator that ripple with sand dunes.


In the early morning of Wednesday, April 7 in UTC time zones, which is around 9 p.m. on Tuesday, April 6 in California, Cassini will make its closest approach to the medium-sized icy moon Dione. Cassini will plunge to within about 500 kilometers (300 miles) of Dione's surface.

This is only Cassini's second close encounter with Dione. The first flyby in October 2005, and findings from the Voyager spacecraft in the 1990s, hinted that the moon could be sending out a wisp of charged particles into the magnetic field around Saturn and potentially exhaling a diffuse plume that contributes material to one of the planet's rings. Like Enceladus, Saturn's more famous moon with a plume, Dione features bright, fresh fractures. But if there were a plume on Dione, it would certainly be subtler and produce less material.

Cassini plans to use its magnetometer and fields and particles instruments to see if it can find evidence of activity at Dione. Thermal mapping by the composite infrared spectrometer will also help in that search. In addition, the visual and infrared mapping spectrometer will examine dark material found on Dione. Scientists would like to understand the source of this dark material.

Cassini has made three previous double flybys and another two are planned in the years ahead. The mission is nearing the end of its first extension, known as the Equinox mission. It will begin its second mission extension, known as the Solstice Mission, in October 2010.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate in Washington. The Cassini orbiter was designed, developed and assembled at JPL.

Extreme Weather Impacts Migratory Birds

Every year, hurricanes and droughts wreak havoc on human lives and property around the world. And according to a pair of new NASA-funded studies, migratory birds also experience severe impacts to their habitats and populations from these events.

While this may not seem like a revelation, the researchers were surprised to find that migratory bird species located as far as 60 miles (100 kilometers) from a hurricane’s path had experienced a long-term loss in population. Those populations took up to five years to rebound from the damage to their forest environments.

At the same time, researchers found that some migratory bird species could experience population losses as high as 13 percent when rainfall levels fall dramatically and cause drought in plains regions. The studies appear in the March edition of Global Change Biology.

"These studies suggest that whether a hurricane or a drought batters an area, migratory habits -- whether birds migrate south or stay put after breeding season -- are a strong predictor of how birds will fare," said Anna Pidgeon, an avian ecologist at the University of Wisconsin-Madison and a NASA-funded co-author of both studies.

"We believe changes in weather and climate are fundamental drivers of migration but, until now, we’ve known little of how changes in climate compel changes in migratory patterns," said Woody Turner, manager of the biodiversity program at NASA’s Headquarters in Washington. "The correlations don’t necessarily mean the environment alone is forcing migratory changes, but they offer a good place to start looking."

Northeastern U.S. Flooding "GOES" to the Movies Via Satellite

The northeastern U.S. was subjected to heavy flooding and damage from late winter storms, and the Geostationary Operational Environmental Satellite, GOES-12 captured a movie of those storms as they dumped heavy rainfall between March 8 and 16, 2010.

"Following the Nor'easter 'parade of blizzards' in February this year, another week-long parade of storms flooded the upper Midwest and Northeastern U.S. in March," said Dennis Chesters of the NASA GOES Project at NASA's Goddard Space Flight Center in Greenbelt, Md. "The merge of three storms in the Midwest was unusual, where the normal pattern is a series of spring storms carried by the prevailing westerlies (winds)."

The GOES-12 operated by the National Oceanic and Atmospheric Administration (NOAA) captures images of U.S. East Coast weather. Those images from March 8-16, 2010 were compiled into a movie by the NASA GOES Project at NASA's Goddard Space Flight Center, Greenbelt, Md.

The movie was created by overlaying the clouds observed several times per hour by NOAA's GOES Imager onto a true-color map previously derived from NASA's Moderate Imaging Spectroradiometer (MODIS) land-mapping instrument. The infrared channels on GOES detect clouds day and night, which are portrayed as grey for low clouds and white for high clouds. The movie compresses nine days into two minutes. It illustrates how continental-scale land/sea/air phenomena come together to make large late winter storms.

Heavy rains that hit the northeast cause flooding, fatalities, power outages and damages. Downed trees from rain-soaked roots toppled power lines. Outages were reported in Connecticut, Maine, New Jersey, New York and Pennsylvania. Literally thousands of trees were reported felled in Connecticut and New York. Flooding forced evacuations and put roadways under water. As far north as Maine, parts of the state received more than eight inches of rain.

As of March 19 for the month of March, Boston recorded 7.45" of rain; Bridgeport, Conn. reported 4.02"; Newark, N.J. reported 5.24"; New York City reported 4.72"; and Portland, Maine reported 3.57" of rain. Most of that rainfall can be attributed to these events.

HELP X-15 Pilot Robert White Dies

On July 17, 1962, Major Robert White flew the X-15 to an altitude of 314,750 feet, or 59 miles, becoming the first "winged astronaut." He was the first to fly at Mach 4, Mach 5 and Mach 6; he was the first to fly a winged vehicle into space. After a career of 'firsts' White died on March 17, 2010.

White was one of the initial pilots selected for the X-15 program, representing the Air Force in the joint program with NASA, the Navy, and North American Aviation. Between April 13, 1960, and Dec. 14, 1962, he made 16 flights in the rocket-powered aircraft.

His July 17, 1962, flight to an altitude of 314,750 feet set a world record. This was 59.6 miles, significantly higher than the 50 miles the Air Force accepted as the beginning of space, qualifying White for astronaut wings. The X-15 rocket-powered aircraft were built by North American Aviation and developed to provide in-flight information and data on aerodynamics, structures, flight controls and the physiological aspects of high-speed, high-altitude flight.

A follow-on program used the aircraft as testbeds to carry various scientific experiments beyond the Earth's atmosphere on a repeated basis. Information gained from the highly successful X-15 program contributed to the development of the Mercury, Gemini and Apollo manned spaceflight programs, and also the space shuttle program. The X-15s made a total of 199 flights and the first aircraft X-15-1, serial number 56-6670, is now located at the National Air and Space Museum in Washington, D.C.

According to an article by Al Hallonquist, White's achievements as an X-15 pilot "allowed him to become the fifth American to attain astronaut wings and only the second Air Force pilot to do this."

Cassini Shows Saturnian Roller Derby, Strange Weather

From our vantage point on Earth, Saturn may look like a peaceful orb with rings worthy of a carefully raked Zen garden, but NASA's Cassini spacecraft has been shadowing the gas giant long enough to see that the rings are a rough and tumble roller derby. It has also revealed that the planet itself roils with strange weather and shifting patterns of charged particles. Two review papers to be published in the March 19 issue of the journal Science synthesize Cassini's findings since arriving at Saturn in 2004.

"This rambunctious system gives us a new feel for how an early solar system might have behaved," said Linda Spilker, a planetary scientist and the new Cassini project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "This kind of deep, rich data can only be collected by an orbiting spacecraft, and we look forward to the next seven years around Saturn bringing even more surprises."


In the paper describing the elegant mess of activity in the rings, lead author Jeff Cuzzi, Cassini's interdisciplinary scientist for rings and dust who is based at NASA Ames Research Center, Moffett Field, Calif., describes how Cassini has shown us that collisions are routine and chunks of ice leave trails of debris in their wakes. Spacecraft data have also revealed how small moons play tug-of-war with ring material and how bits of rubble that would otherwise join together to become moons are ultimately ripped apart by the gravitational pull that Saturn exerts.

During equinox, the period when sunlight hits the rings exactly edge-on, Cassini witnessed rings that are normally flat - about tens of meters (yards) thick - being flipped up as high as the Rocky Mountains.

The spacecraft has also shown that the rings are composed mostly of water ice, with a mysterious reddish contaminant that could be rust or small organic molecules similar to those found in red vegetables on Earth.

"It has been amazing to see the rings come to life before our very eyes, changing even as we watch, being colorful and taking on a tangible, 3-D nature," Cuzzi said. "The rings were still a nearly unstructured object in even the best telescopes when I was a grad student, but Cassini has brought us an intimate familiarity with them."

Cuzzi said Cassini scientists were surprised to find such fine-scale structure nearly everywhere in the rings, forcing them to be very careful about generalizing their findings across the entire ring disk. The discovery that the rings are clumpy has also called into question some of the previous estimates for the mass of the rings because there might be clusters of material hidden inside of the clumps that have not yet been measured.

See Spot on Jupiter. See Spot Glow.

New thermal images from powerful ground-based telescopes show swirls of warmer air and cooler regions never seen before within Jupiter's Great Red Spot, enabling scientists to make the first detailed interior weather map of the giant storm system.

The observations reveal that the reddest color of the Great Red Spot corresponds to a warm core within the otherwise cold storm system, and images show dark lanes at the edge of the storm where gases are descending into the deeper regions of the planet. These types of data, detailed in a paper appearing in the journal Icarus, give scientists a sense of the circulation patterns within the solar system's best-known storm system.

"This is our first detailed look inside the biggest storm of the solar system," said Glenn Orton, a senior research scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., who was one of the authors of the paper. "We once thought the Great Red Spot was a plain old oval without much structure, but these new results show that it is, in fact, extremely complicated."

Sky gazers have been observing the Great Red Spot in one form or another for hundreds of years, with continuous observations of its current shape dating back to the 19th century. The spot, which is a cold region averaging about 110 Kelvin (minus 260 degrees Fahrenheit) is so wide about three Earths could fit inside its boundaries.

The thermal images obtained by giant 8-meter (26-foot) telescopes used for this study -- the European Southern Observatory's Very Large Telescope in Chile, the Gemini Observatory telescope in Chile and the National Astronomical Observatory of Japan's Subaru telescope in Hawaii -- have provided an unprecedented level of resolution and extended the coverage provided by NASA's Galileo spacecraft in the late 1990s. Together with observations of the deep cloud structure by the 3-meter (10-foot) NASA Infrared Telescope Facility in Hawaii, the level of thermal detail observed from these giant observatories is comparable to visible-light images from NASA's Hubble Space Telescope for the first time.

One of the most intriguing findings shows the most intense orange-red central part of the spot is about 3 to 4 Kelvin (5 to 7 degrees Fahrenheit) warmer than the environment around it, said Leigh Fletcher, the lead author of the paper, who completed much of the research as a postdoctoral fellow at JPL and is currently a fellow at the University of Oxford in England. This temperature differential might not seem like a lot, but it is enough to allow the storm circulation, usually counter-clockwise, to shift to a weak clockwise circulation in the very middle of the storm. Not only that, but on other parts of Jupiter, the temperature change is enough to alter wind velocities and affect cloud patterns in the belts and zones.

"This is the first time we can say that there's an intimate link between environmental conditions -- temperature, winds, pressure and composition - and the actual color of the Great Red Spot," Fletcher said. "Although we can speculate, we still don't know for sure which chemicals or processes are causing that deep red color, but we do know now that it is related to changes in the environmental conditions right in the heart of the storm."

Solar 'Conveyor Belt' Runs at Record-High Speeds

This images shows the association of magnetic field with sunspots and coronal loops. It begins with images in "white light" (visible light) from the ESA/NASA SOHO Mission MDI instrument showing the presence of sunspots (darker, cooler regions about the size of the Earth) and the 27-day rotation of the sun. The movie then dissolves to magnetic images from MDI showing how strong magnetic fields are associated with sunspots but weaker magnetic elements are always present and in constant motion. (White represents field directed out of the Sun while black represents field directed into the sun.) The movie then dissolves to images obtained in extreme ultraviolet light by the EIT instrument on SOHO. This reveals the hot coronal loops that are associated with the magnetic features. The movie ends with a zoom-in to a single region which is followed as it rotates across the visible disk of the sun by the extreme ultraviolet imaging instrument on the NASA TRACE spacecraft. This final segment illustrates how the constant motion of the magnetic elements produces impulsive heating of material in the coronal magnetic loops.