Tracing the Big Picture of Mars' Atmosphere

One of the instruments on a 2016 mission to orbit Mars will provide daily maps of global, pole-to-pole, vertical distributions of the temperature, dust, water vapor and ice clouds in the Martian atmosphere.

The joint European-American mission, ExoMars Trace Gas Orbiter, will seek faint gaseous clues about possible life on Mars. This instrument, called the ExoMars Climate Sounder, will supply crucial context with its daily profiling of the atmosphere's changing structure.


The European Space Agency and NASA have selected five instruments for ExoMars Trace Gas Orbiter. The European Space Agency will provide one instrument and the spacecraft. NASA will provide four instruments, including ExoMars Climate Sounder, which is coming from NASA's Jet Propulsion Laboratory, Pasadena, Calif.

Two of the other selected instruments are spectrometers -- one each from Europe and the United States -- designed to detect very low concentrations of methane and other important trace gases in the Martian atmosphere.

"To put the trace-gas measurements into context, you need to know the background structure and circulation of the atmosphere," said JPL's Tim Schofield, principal investigator for the ExoMars Climate Sounder. "We will provide the information needed to understand the distribution of trace gases identified by the spectrometers. We'll do this by characterizing the role of atmospheric circulation and aerosols, such as dust and ice, in trace-gas transport and in chemical reactions in the atmosphere affecting trace gases."

The ExoMars Climate Sounder is an infrared radiometer designed to operate continuously, day and night, from the spacecraft's orbit about 400 kilometers (about 250 miles) above the Martian surface. It can pivot to point downward or toward the horizon, measuring temperature, water vapor, dust and ices for each 5-kilometer (3-mile) increment in height throughout the atmosphere from ground level to 90 kilometers (56 miles) altitude.

Schofield and his international team have two other main goals for the investigation, besides aiding in interpretation of trace-gas detections.

One is to extend the climate mapping record currently coming from a similar instrument, the Mars Climate Sounder, on NASA's Mars Reconnaissance Orbiter, which has been working at Mars since 2006. The orbital geometry of the Mars Reconnaissance Orbiter mission enables this sounder to record atmospheric profiles only at about 3 p.m. and 3 a.m. during the Martian day, except near the poles. The ExoMars Trace Gas Orbiter will fly an orbital pattern that allows the spacecraft to collect data at all times of day, at all latitudes.

"We'll fill in information about variability at different times of day, and we'll add to the number of Mars years for understanding year-to-year variability," said Schofield. "The most obvious year-to-year change is that some years have global dust storms and others don't. We'd like to learn whether there's anything predictive for anticipating the big dust storms, and what makes them so variable from year to year."

A third research goal is to assist future landings on Mars by supplying information about the variable density of the atmosphere. At a chosen landing site, atmospheric density can change from one day to the next, affecting a spacecraft's descent.

"We want to provide background climatology for what to expect at a given site, in a given season, for a particular time of day, and also nearly real-time information for the atmospheric structure in the days leading up to the landing of a spacecraft launched after 2016," said Schofield.

The 2016 ExoMars Trace Gas Orbiter is the first in a series of planned Mars mission collaborations of the European Space Agency and NASA. A variable presence of small amounts of methane in the Martian atmosphere has been indicated from orbital and Earth-based observations. A key goal of the mission is to gain a better understanding of methane and other trace gases that could be evidence about possible biological activity. Methane can be produced both biologically and without life.

Besides the two spectrometers and the climate sounder, the orbiter's selected instruments include two NASA-provided imagers: a high-resolution, stereo, color imager, and a wide-angle, color, weather camera. The orbiter will also serve as a communications relay for missions on the surface of Mars and will carry a European-built descent-and-landing demonstration module designed to operate for a few days on the Mars surface. JPL, a division of the California Institute of Technology, manages NASA's roles in the mission.

A Strange Ring Galaxy

Is this one galaxy or two? Astronomer Art Hoag first asked this question when he chanced upon this unusual extragalactic object. On the outside is a ring dominated by bright blue stars, while near the center lies a ball of much redder stars that are likely much older. Between the two is a gap that appears almost completely dark. How Hoag's Object formed remains unknown, although similar objects have been identified and collectively labeled as a form of ring galaxy. Genesis hypotheses include a galaxy collision billions of years ago and the gravitational effect of a central bar that has since vanished.

This image, taken by the Hubble Space Telescope in July 2001, reveals unprecedented details of Hoag's Object and may yield a better understanding. Hoag's Object spans about 100,000 light years and lies about 600 million light years away toward the constellation of the Snake (Serpens). Coincidentally, visible in the gap (at about one o'clock) is yet another ring galaxy that likely lies far in the distance.

Hydrogen Sulfide and Dust Plumes on Namibia's Coast

Cloudless skies allowed a clear view of dust and hydrogen sulfide plumes along the coast of Namibia in early August 2010. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this natural-color image on Aug. 10, 2010.

Multiple dust plumes blow off the coast toward the ocean, most or all of them probably arising from streambeds. Unlike the reddish-tan sands comprising the dunes directly south of the Kuiseb River, the stream-channel sediments are lighter in color. Wind frequently pushes dust plumes seaward along the Namibian Coast. Easterly trade winds blow from the Indian Ocean over the African continent, losing much of their moisture as they go. The winds are hot and dry as they pass over Namibia’s coastal plain, where they are prone to stir fine sediments.

Even with dust plumes overhead, the marked change in land cover is obvious along the Kuiseb River. South of the river, sand dunes predominate, but the vegetation along the Kuiseb River prevents the dunes from advancing northward. North of the river, the land surface consists primarily of gravel plains punctuated by rocky hills.

Hydrogen sulfide appears as a swath of irridescent green running parallel to the coast north of Walvis Bay. A 2009 study linked the emissions in this region to ocean currents, biological activity in the water column, and carbon-rich organic sediments under the water column. The meeting of hydrogen sulfide gas and oxygen-rich surface waters causes pure sulfur to precipitate into the water. The sulfur’s yellow color makes the water appear green to the satellite sensor.

Launch Preps Move Ahead for Mission to International Space Station

During space shuttle Discovery's final spaceflight, the STS-133 crew members will take important spare parts to the International Space Station along with the Express Logistics Carrier-4. Discovery is being readied for flight inside Kennedy's Orbiter Processing Facility-3 while its solid rocket boosters are stacked inside the nearby Vehicle Assembly Building. STS-133 is slated to launch Nov. 1.

Massive Attack

This image shows the eruption of a galactic “super-volcano” in the massive galaxy M87, as witnessed by NASA's Chandra X-ray Observatory and NSF's Very Large Array (VLA). At a distance of about 50 million light years, M87 is relatively close to Earth and lies at the center of the Virgo cluster, which contains thousands of galaxies.

The cluster surrounding M87 is filled with hot gas glowing in X-ray light (and shown in blue) that is detected by Chandra. As this gas cools, it can fall toward the galaxy's center where it should continue to cool even faster and form new stars.

However, radio observations with the VLA (red) suggest that in M87 jets of very energetic particles produced by the black hole interrupt this process. These jets lift up the relatively cool gas near the center of the galaxy and produce shock waves in the galaxy's atmosphere because of their supersonic speed. The interaction of this cosmic “eruption” with the galaxy's environment is very similar to that of the Eyjafjallajokull volcano in Iceland that occurred in 2010. With Eyjafjallajokull, pockets of hot gas blasted through the surface of the lava, generating shock waves that can be seen passing through the grey smoke of the volcano. This hot gas then rises up in the atmosphere, dragging the dark ash with it. This process can be seen in a movie of the Eyjafjallajokull volcano where the shock waves propagating in the smoke are followed by the rise of dark ash clouds into the atmosphere.

In the analogy with Eyjafjallajokull, the energetic particles produced in the vicinity of the black hole rise through the X-ray emitting atmosphere of the cluster, lifting up the coolest gas near the center of M87 in their wake. This is similar to the hot volcanic gases drag up the clouds of dark ash. And just like the volcano here on Earth, shockwaves can be seen when the black hole pumps energetic particles into the cluster gas.

Move Over Caravaggio: Cassini's Light and Dark Moons

NASA's Cassini spacecraft has returned Saturnian moon images from its flyby late last week, revealing light and dark contrasts worthy of chiaroscuro painters like Caravaggio.
The flyby on August 13 targeted the geyser moon Enceladus, but also brought Cassini close to two other moons--Tethys and Dione.
The raw images include the best ones to date of Penelope crater on the icy moon Tethys . Penelope crater, which is 150 kilometers (90 miles) wide, is the second-largest crater on Tethys.
Cassini was also able to obtain a portrait of Enceladus over the bright arc of Saturn's atmosphere and a moody still life of one of the "tiger stripe" fissures at the Enceladus south polar region on the cusp of darkness . This particular "tiger stripe" -- which is the nickname for the fissures spewing water vapor and organic particles out into space - is called Damascus Sulcus. It was also the subject of a heat scan by Cassini's composite infrared spectrometer. Scientists are still analyzing the results.
Images of Dione highlight the moon's battered surface .
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
More raw images from the Enceladus flyby, dubbed "E11," are available at: http://saturn.jpl.nasa.gov/photos/raw/.
More information about the Cassini-Huygens mission is at: http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov/ .

Fermi Detects 'Shocking' Surprise from Supernova's Little Cousin

Astronomers using NASA's Fermi Gamma-ray Space Telescope have detected gamma-rays from a nova for the first time, a finding that stunned observers and theorists alike. The discovery overturns the notion that novae explosions lack the power to emit such high-energy radiation.

A nova is a sudden, short-lived brightening of an otherwise inconspicuous star. The outburst occurs when a white dwarf in a binary system erupts in an enormous thermonuclear explosion.

"In human terms, this was an immensely powerful eruption, equivalent to about 1,000 times the energy emitted by the sun every year," said Elizabeth Hays, a Fermi deputy project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "But compared to other cosmic events Fermi sees, it was quite modest. We're amazed that Fermi detected it so strongly."

Gamma rays are the most energetic form of light, and Fermi's Large Area Telescope (LAT) detected the nova for 15 days. Scientists believe the emission arose as a million-mile-per-hour shock wave raced from the site of the explosion.

Juno Armored Up to Go to Jupiter

NASA's Juno spacecraft will be forging ahead into a treacherous environment at Jupiter with more radiation than any other place NASA has ever sent a spacecraft, except the sun. In a specially filtered cleanroom in Denver, where Juno is being assembled, engineers recently added a unique protective shield around its sensitive electronics. New pictures of the assembly were released today.
"Juno is basically an armored tank going to Jupiter," said Scott Bolton, Juno's principal investigator, based at Southwest Research Institute in San Antonio. "Without its protective shield, or radiation vault, Juno's brain would get fried on the very first pass near Jupiter."
An invisible force field filled with high-energy particles coming off from Jupiter and its moons surrounds the largest planet in our solar system. This magnetic force field, similar to a less powerful one around Earth, shields Jupiter from charged particles flying off the sun. The electrons, protons and ions around Jupiter are energized by the planet's super-fast rotation, sped up to nearly the speed of light.


Jupiter's radiation belts are shaped like a huge doughnut around the planet's equatorial region and extend out past the moon Europa, about 650,000 kilometers (400,000 miles) out from the top of Jupiter's clouds.
"For the 15 months Juno orbits Jupiter, the spacecraft will have to withstand the equivalent of more than 100 million dental X-rays," said Bill McAlpine, Juno's radiation control manager, based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "In the same way human beings need to protect their organs during an X-ray exam, we have to protect Juno's brain and heart."
The strategy? Give Juno a kind of six-sided lead apron on steroids.
With guidance from JPL and the principal investigator, engineers at Lockheed Martin Space Systems designed and built a special radiation vault made of titanium for a centralized electronics hub. While other materials exist that make good radiation blockers, engineers chose titanium because lead is too soft to withstand the vibrations of launch, and some other materials were too difficult to work with.
Each titanium wall measures nearly a square meter (nearly 9 square feet) in area, about 1 centimeter (a third of an inch) in thickness, and 18 kilograms (40 pounds) in mass. This titanium box -- about the size of an SUV's trunk – encloses Juno's command and data handling box (the spacecraft's brain), power and data distribution unit (its heart) and about 20 other electronic assemblies. The whole vault weighs about 200 kilograms (500 pounds).
The vault is not designed to completely prevent every Jovian electron, ion or proton from hitting the system, but it will dramatically slow down the aging effect radiation has on electronics for the duration of the mission.
"The centralized radiation vault is the first of its kind," Bolton said. "We basically designed it from the ground up."
When NASA's Galileo spacecraft visited Jupiter from 1995 to 2003, its electronics were shielded by special components designed to be resistant to radiation. Galileo also didn't need to survive the harshest radiation regions, where Juno will operate.
But Juno isn't relying solely on the radiation vault. Scientists designed a path that takes Juno around Jupiter's poles, spending as little time as possible in the sizzling radiation belts around Jupiter's equator. Engineers also used designs for electronics already approved for the Martian radiation environment, which is harsher than Earth's, though not as harsh as Jupiter's. Parts of the electronics were made from tantalum, or tungsten, another radiation-resistant metal. Some assemblies also have their own mini-vaults for protection.
Packing the assemblies next to each other allows them to shield their neighbors. In addition, engineers wrapped copper and stainless steel braids like chain mail around wires connecting the electronics to other parts of the spacecraft.
JPL tested pieces of the vault in a radiation environment similar to Jupiter's to make sure the design will be able to handle the stress of space flight and the Jupiter environment, McAlpine said. In a special lead-lined testing tub there, they battered pieces of the spacecraft with gamma rays from radioactive cobalt pellets and analyzed the results for Juno's expedition.
The vault was lifted onto Juno's propulsion module on May 19 at Lockheed Martin's high-bay cleanroom. It will undergo further testing once the whole spacecraft is put together. The assembly and testing process, which also includes installing solar panels for the first-ever solar-powered mission to Jupiter, is expected to last through next spring. Juno is expected to launch in August 2011.
"The Juno assembly is proceeding well," said Tim Gasparrini, Lockheed Martin program manager. "We have a number of the flight and test unit spacecraft avionics components installed into the radiation vault for system testing and we have also just installed the first instrument, the microwave radiometer."
JPL manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute at San Antonio, Texas. Lockheed Martin Space Systems, Denver, Colo., is building the spacecraft. The Italian Space Agency in Rome is contributing an infrared spectrometer instrument and a portion of the radio science experiment.
More information about Juno is online at http://www.nasa.gov/juno .

Spacecraft Observes Coronal Mass Ejection

On August 1st, the sun emitted a C-class solar flare that spawned what scientists call a coronal mass ejection, or CME, headed toward Earth. The CME impacted Earth's magnetic field August 3rd. CMEs occasionally hit Earth. This CME will have few noticeable consequences beyond producing an aurorae.

The CME hit Earth's magnetic field on August 3rd at 1740 UT. The impact sparked a G2-class geomagnetic storm that lasted nearly 12 hours time enough for auroras to spread all the way from Europe to North America. The possible arrival of a second CME on August 4th might provide even better spectacular auroral displays.

CMEs are large clouds of charged particles that are ejected from the sun over the course of several hours and can carry up to ten billion tons of plasma. They expand away from the sun at speeds as high as a million miles an hour. A CME can make the 93 million mile journey to Earth in just two to four days. Stronger solar storms could cause adverse impacts to space based assets and technological infrastructure on Earth.

The sun goes through a regular activity cycle about 11 years long. The last solar maximum occurred in 2001 and its recent extreme solar minimum was particularly weak and long lasting. These kinds of eruptions are one of the first signs that the sun is waking up and heading toward another solar maximum expected in the 2013 time frame.

Coronal Mass Ejection Headed for Earth

On August 1st around 0855 UT, Earth orbiting satellites detected a C3-class solar flare. The origin of the blast was Earth facing sunspot 1092. C-class solar flares are small and usually have few noticeable consequences here on Earth besides aurorae. This one has spawned a coronal mass ejection heading in Earth's direction.

Coronal mass ejections are large clouds of charged particles that are ejected from the Sun over the course of several hours and can carry up to ten billion tons of plasma. They expand away from the Sun at speeds as high as a million miles an hour. A CME can make the 93-million mile journey to Earth in just three to four days.

When a coronal mass ejection reaches Earth, it interacts with our planet’s magnetic field, potentially creating a geomagnetic storm. Solar particles stream down the field lines toward Earth’s poles and collide with atoms of nitrogen and oxygen in the atmosphere, resulting in spectacular auroral displays. On the evening of August 3rd/4th, skywatchers in the northern U.S. and other countries should look toward the north for the rippling dancing “curtains” of green and red light.

The Sun goes through a regular activity cycle about 11 years long. The last solar maximum occurred in 2001 and its recent extreme solar minimum was particularly weak and long lasting. These kinds of eruptions are one of the first signs that the Sun is waking up and heading toward another solar maximum expected in the 2013 time frame.

NASA's Hibernating Mars Rover May Not Call Home

PASADENA, Calif. NASA mission controllers have not heard from the Mars Exploration Rover Spirit since March 22, and the rover is facing its toughest challenge yet trying to survive the harsh Martian winter.

The rover team anticipated Spirit would go into a low power "hibernation" mode since the rover was not able to get to a favorable slope for its fourth Martian winter, which runs from May through November. The low angle of sunlight during these months limits the power generated from the rover's solar panels. During hibernation, the rover suspends communications and other activities so available energy can be used to recharge and heat batteries, and to keep the mission clock running.

On July 26, mission managers began using a paging technique called "sweep and beep" in an effort to communicate with Spirit.

Spirit is designed to wake up from its hibernation and communicate with Earth when its battery charge is adequate. But if the batteries have lost too much power, Spirit's clock may stop and lose track of time. The rover could still reawaken, but it would not know the time of day, a situation called a "mission clock fault." Spirit would start a new timer to wake up every four hours and listen for a signal from Earth for 20 minutes of every hour while the sun is up.

NASA's JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA's Science Mission Directorate in Washington.