samedi 21 novembre 2015

LHC: A proton 'reference' run to prepare for lead












CERN - European Organization for Nuclear Research logo.

November 21, 2015

With the proton run at 13 teraelectronvolts (TeV) now over for 2015, preparations are in full swing for the Large Hadron Collider (LHC) to investigate lead ions, as it does for part of each year. But first, the Operations team is colliding protons at lower energies than usual to provide a baseline for the lead run.

Collisions between lead ions are much more complex than those between single protons. When lead ions collide at energies of several teraelectronvolts (TeV), the extreme conditions give rise to a hot, dense soup of particles known as "quark-gluon plasma" – a state of matter thought to have existed just after the Big Bang. Experiments at CERN study this plasma to gain insights into the nature of the early universe.


Image above: The LHC is colliding protons at the lower energy of 2.51 teraelectronvolts (TeV) per beam, to provide a baseline for collisions between lead ions. (Image: Maximilien Brice).

To cut through the complexity of the lead fireball, CERN physicists will compare their lead-lead collision data with previous measurements from proton-proton, as well as proton-lead collisions.

"A lead nucleus in the LHC has 82 times the energy of a proton," says accelerator physicist John Jowett. "But that energy is distributed among its 208 nucleons (the protons and neutrons that make up the lead nucleus). As 82 divided by 208 is 0.39, it follows that one proton or nucleon in a colliding lead nucleus has just less than 40% of the energy of an independent proton colliding."

This is why, in today’s proton-proton run, the Operations team has adjusted the energy of the proton beam downwards. "For the upcoming collisions between lead ions, we will reduce the LHC’s magnetic fields a little – from the levels corresponding to a proton energy of 6.5 TeV, to 6.37 TeV – because that gives us the same centre-of-mass energy of 5.02 TeV per nucleon pair as we had in 2013, when we collided 4 TeV protons with lead ions," says Jowett. "The proton-proton reference data being taken this week is at 2.51 TeV per beam, which is the corresponding energy for protons. So finally the experiments will be able to make precise comparisons among data sets with three different combinations of particles colliding at the same effective energy."

Accelerator physicist Jorg Wenninger of the LHC Operations team says that preparing the LHC for proton beams at 2.51 TeV was relatively straightforward. “We had to re-commission the run to lower energy, find the collisions and set up all the conditions for physics,” he says. “But we already ran the LHC at high energy this year, so we can profit from experience. We will however apply one innovation: instead of squeezing the beam optics at the collision points after the energy ramp, we will perform both operations in parallel. If this is working smoothly, we may decide to use the same technique to shorten the LHC cycles in 2016 and beyond. ”

"This proton-proton reference run will give the experiments an idea of what the proton-proton equations look like; it gives them a comparison for the upcoming lead-lead collisions,” says Mike Lamont of the LHC Operations team.

The LHC experiments are also preparing for the lead-lead run. ALICE is specialised for heavy-ion physics, ATLAS and CMS have added calorimeters to the LHC tunnel, and for the first time, the LHCb experiment will take data from these heavy-ion collisions.

Note:

CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 22 Member States.

Related articles:

LHC completes proton run for 2015, preps for lead:
http://orbiterchspacenews.blogspot.ch/2015/11/lhc-completes-proton-run-for-2015-preps.html

Engineers refine protection system for LHC magnets:
http://orbiterchspacenews.blogspot.ch/2015/09/engineers-refine-protection-system-for.html

ATLAS and CMS experiments shed light on Higgs properties:
http://orbiterchspacenews.blogspot.ch/2015/09/atlas-and-cms-experiments-shed-light-on.html

LHC progresses towards higher intensities:
http://orbiterchspacenews.blogspot.ch/2015/08/lhc-progresses-towards-higher.html

Related links:

Large Hadron Collider (LHC): http://home.cern/topics/large-hadron-collider

ALICE experiments: http://home.cern/about/experiments/alice

ATLAS experiments: http://home.cern/about/experiments/atlas

CMS experiments: http://home.cern/about/experiments/cms

LHCb experiments: http://home.cern/about/experiments/lhcb

Quark-gluon plasma: http://home.cern/about/physics/heavy-ions-and-quark-gluon-plasma

Big Bang: http://home.cern/about/physics/early-universe

For more information about European Organization for Nuclear Research (CERN), Visit: http://home.cern/

Image (mentioned), Text, Credits: CERN/Cian O'Luanaigh.

Best regards, Orbiter.ch

Khrunichev Center: ISS - 17 years in orbit












ROSCOSMOS - Zarya IA/R - ISS power block 1 patch.

November 21, 2015

17 years ago, on 20 November 1998, it began the construction of the International Space Station (ISS). From the Baikonur cosmodrome was successfully launched Proton rocket with the Functional Cargo Block (FGB) "Dawn."

November 20, 1998 - Proton-K launch with Zarya - ISS block 1

The International Space Station - the largest scientific and technical unique space project, which combined intellectual and financial resources of many countries.

Work on defining the configuration of the ISS with Russia began in August 1993. In early September 1993 signed an intergovernmental agreement on Russia's participation in the creation of the ISS and the US participation in the program of the Russian "Mir". In September 1993, a team of NASA and industrial firms visited the Khrunichev Center to become familiar with its capabilities to participate in the ISS program.

October 4, 1993 at the Russian Federal Space Agency (FKA) held a meeting with representatives of the Khrunichev. MV Khrunichev, RSC "Energia», NASA and the Boeing company, where it was decided to use as the first module of the ISS power block "Zarya" - an analog of heavy transport ships and modules for space stations created in the Center Khrunichev more than 20 years. The lead developer and manufacturer of module "Zarya" was the Khrunichev Center. Total unit participated in the creation of about 240 Russian companies.

FGB "Zarya" - ISS block 1 in orbit

Over the years, the construction of the space station to the FGB "Zarya" were docked American module Unity (1998) and the Russian module "Zvezda" (2000). In 2001, the ISS were attached: laboratory module Destiny, airlock Quest and docking compartment "Pirs". Then added to the ISS American module Harmony (2007), the European module Columbus (2008) and the Japanese Kibo (2008).

Khrunichev Center held a large amount of work to extend the service life of the ISS until 2024. At the Khrunichev Center is involved in the final stage of creating the third module of the Russian segment of the ISS - a multipurpose laboratory module "Science."

ROSCOSMOS Press Release: http://www.federalspace.ru/21844/

Images, Text, Credits: ROSCOSMOS/Khrunichev Center/Wikimedia/Translation: Orbiter.ch Aerospace/Roland Berga.

Best regards, Orbiter.ch

vendredi 20 novembre 2015

A Day on Pluto, a Day on Charon












NASA - New Horizons Mission logo.

Nov. 20, 2015


Images above: On approach in July 2015, the cameras on NASA’s New Horizons spacecraft captured Pluto rotating over the course of a full “Pluto day.” The best available images of each side of Pluto taken during approach have been combined to create this view of a full rotation. Images Credits: NASA/JHUAPL/SwRI.

Pluto’s day is 6.4 Earth days long. The images were taken by the Long Range Reconnaissance Imager (LORRI) and the Ralph/Multispectral Visible Imaging Camera as the distance between New Horizons and Pluto decreased from 5 million miles (8 million kilometers) on July 7 to 400,000 miles (about 645,000 kilometers) on July 13. The more distant images contribute to the view at the 3 o’clock position, with the top of the heart-shaped, informally named Tombaugh Regio slipping out of view, giving way to the side of Pluto that was facing away from New Horizons during closest approach on July 14.  The side New Horizons saw in most detail – what the mission team calls the “encounter hemisphere” – is at the 6 o’clock position.

These images and others like them reveal many details about Pluto, including the differences between the encounter hemisphere and the so-called “far side” hemisphere seen only at lower resolution. Dimples in the bottom (south) edge of Pluto’s disk are artifacts of the way the images were combined to create these composites.


Images above: On approach to the Pluto system in July 2015, the cameras on NASA’s New Horizons spacecraft captured images of the largest of Pluto’s five moons, Charon, rotating over the course of a full day. The best currently available images of each side of Charon taken during approach have been combined to create this view of a full rotation of the moon. Images Credits: NASA/JHUAPL/SwRI.

Charon – like Pluto – rotates once every 6.4 Earth days. The photos were taken by the Long Range Reconnaissance Imager (LORRI) and the Ralph/Multispectral Visible Imaging Camera from July 7-13, as New Horizons closed in over a range of 6.4 million miles (10.2 million kilometers). The more distant images contribute to the view at the 9 o’clock position, with few of the signature surface features visible, such as the cratered uplands, canyons, or rolling plains of the informally named Vulcan Planum. The side New Horizons saw in most detail, during closest approach on July 14, 2015, is at the 12 o’clock position.

These images and others like them reveal many details about Charon, including how similar looking the encounter hemisphere is to the so-called “far side” hemisphere seen only at low resolution – which is the opposite of the situation at Pluto. Dimples in the bottom (south) edge of Charon’s disk are artifacts of the way the New Horizons images were combined to create these composites.

For more information about New Horizons, visit: http://www.nasa.gov/mission_pages/newhorizons/main/index.html

Images (mentioned), Text, Credits: NASA/Tricia Talbert.

Rosetta - Comet on 17 November 2015












ESA - Rosetta Mission patch.

November 20, 2015

NAVCAM image taken on 17 November 2015, when Rosetta was 141.4 km from the nucleus of Comet 67P/Churyumov-Gerasimenko. The spacecraft has not been this close to the nucleus since weeks before perihelion, when the increased amounts of dust due to enhanced comet activity started interfering with navigation and Rosetta remained at larger distances from 67P/C-G.


Image above: Single frame enhanced NAVCAM image of Comet 67P/C-G taken on 17 November 2015. Credits: ESA/Rosetta/NAVCAM – CC BY-SA IGO 3.0.

The scale is 12.1 m/pixel and the image measures 12.3 km across; the contrast was increased to bring out the comet's activity.

In this orientation, the large comet lobe is on the lower left, and the small lobe on the upper right. Outflows of dust are visible around the nucleus, particularly to the left.

On the small lobe, the circular depression of Hatmehit is well in sight, pointing to the upper right corner of the image, with the rougher terrains of Bastet visible below and the Wosret region to its left. Abydos, the final resting place of the lander Philae, is roughly at the centre of the small lobe in this view.

Hints of Sobek are visible on the comet's neck; on the large lobe are parts of Babi (right), smooth areas on Aker and Khepry (centre), and the more rugged Anhur and Khonsu (left).

For more information about Rosetta mission, visit: http://www.esa.int/Our_Activities/Space_Science/Rosetta

Rosetta overview: http://www.esa.int/Our_Activities/Space_Science/Rosetta_overview

Rosetta in depth:http://sci.esa.int/rosetta

Rosetta factsheet: http://www.esa.int/Our_Activities/Space_Science/Rosetta/Rosetta_factsheet

Frequently asked questions: http://www.esa.int/Our_Activities/Space_Science/Rosetta/Frequently_asked_questions

Image (mentioned), Text, Credit: European Space Agency (ESA).

Best regards, Orbiter.ch

2015 and 1997 El Niños: Déjà vu, or Something New?












NASA patch.

November 20, 2015

El Niño: An unusually warm pool of water off the west coast of South America, usually arriving around Christmas time, linked with complex, large-scale interactions between the atmosphere and ocean in the Pacific.

If you live anywhere El Niño has important impacts, you've heard forecasters say this year's event looks just like the monster El Niño of 1997-98. NASA satellite images of the Pacific Ocean in November 1997 and November 2015 show almost identical, large pools of warm water in the eastern equatorial Pacific. The National Weather Service has forecast that impacts this winter will resemble those in 1997, when California and the South suffered floods, mudslides and tornadoes, while residents of the Upper Midwest saved $2 billion to $7 billion in heating costs throughout their unusually warm winter.


Image above: In this side-by-side visualization, Pacific Ocean sea surface height anomalies during the 1997-98 El Niño (left) are compared with 2015 Pacific conditions (right). The 1997 data are from the NASA/CNES Topex/Poseidon mission; the current data are from the NASA/CNES/NOAA/EUMETSAT Jason-2 mission. Image and caption: NASA/JPL-Caltech.

When it comes to El Niños, however, there are no identical twins. This year's event hasn't always resembled the '97 one. Satellite observations from early '97 and early '15 show conditions in the Pacific Ocean that were, well, oceans apart.

In its "normal" state, the Pacific is warm on the western side and cooler in the east. That's what the ocean looked like in 1996 and early 1997. Conversely, over the past 18 months or so, satellite images have shown a large pool of warm water hovering around the equator in the central Pacific -- neither west, as in a normal year, nor east, as in a typical El Niño.

"That warm patch started last year and it never disappeared. It's very peculiar behavior," said Tong Lee, an oceanographer at NASA's Jet Propulsion Laboratory, Pasadena, California.


Animation above: In this side-by-side animation,Pacific Ocean sea surface height anomalies during the 1997-98 El Niño (left) are compared with 2015 Pacific conditions (right). The 1997 data are from the NASA/CNES Topex/Poseidon mission; the current data are from the NASA/CNES/NOAA/EUMETSAT Jason-2 mission. Animation Credits: NASA/JPL-Caltech.

In the first decade of the 2000s, scientists began noticing that warm pools were appearing more frequently in the central equatorial Pacific. Since they look like El Niños but are in the wrong place, some began calling them "central Pacific El Niños." Others use the name "El Niño Modoki," Japanese for (roughly) "almost but not quite an El Niño."

"Whether we have [different] flavors of El Niño, central versus eastern Pacific El Niños, or a continuum is an actively debated topic," said JPL's Michelle Gierach, who studies the ocean response to El Niño.

However it's classified, the central Pacific phenomenon tends to have different global impacts than the classic El Niño variety. In the United States, a strong, classic El Niño usually heralds a warmer Northwest and colder Southeast. The central Pacific version is associated with a warmer Northeast and colder Southwest.

But the central Pacific isn't the only part of the ocean that has been behaving oddly in the last few years. "Before the developing 2015 El Niño, there was prolonged anomalous warming off the West Coast of North America called the Blob," Gierach said. Named by Nick Bond at the University of Washington, Seattle, the Blob is the largest pool of warmer-than-normal water in the North Pacific Ocean in recorded history. It formed about two years ago near the Gulf of Alaska and grew to span the entire U.S. West Coast, merging with warm pools off Baja California and in the Bering Sea. "The occurrence of this phenomenon in association with El Niño is not normal, based upon our satellite record, and the combination of the two has greater potential to affect marine life."


Image above: Flooding on the Russian River in northern California during the 1997-98 El Niño event. Image Credits: FEMA/Dave Gatley.

Wherever El Niño warms the ocean, it reduces the nutrients upwelled from the ocean depth. From satellites, this can be seen in declining concentrations of sea surface chlorophyll, a green pigment found in phytoplankton. These microscopic plants are the lowest level of the ocean food web. "Phytoplankton, like people, have environments that they favor," Gierach said. Just like any other plant, they like specific light conditions, temperatures and nutrients. When those conditions change, phytoplankton species change as well. That cascades up through the marine food chain. These changes in phytoplankton, fish and other marine life have already been observed in association with both the Blob and El Niño.

Predicting El Niños and Their Impacts

Forecasters weren't sure how the central Pacific warm event of 2014 would shape up, and they have been cautious in predicting the evolution of this year's event until very recently. That's because the development of an El Niño is intrinsically difficult to forecast much more than three to six months ahead of time. Part of the difficulty is that we only have a few decades of observational records of the ocean and atmosphere to test the models used for forecasting. Since 1992, when the U.S./European Topex/Poseidon and Jason series of ocean altimetry satellites began providing comprehensive views of Pacific sea surface height (a measure of heat in the ocean), there have only been six El Niños -- not a large enough sample for scientists to develop reliable assumptions on their behavior.

"The El Niño cycle is three to seven years," Lee pointed out. "If you predict it wrong, you will have to wait for years to try again. Only when we have decades of satellite data can we test our prediction skill."

When it comes to forecasting the impacts of an El Niño, however, the picture is a bit different. "Forecasting the impacts for a small to medium El Niño is difficult to impossible," said JPL climatologist Bill Patzert. "They're not big enough to impact weather patterns across the planet. But when you have a super El Niño, like this year and 97-98, it's probably the most powerful tool long-range forecasters have."

What Do the Scientists Expect?

Lee thinks the coming winter could be a double whammy. "Because the warming in the central equatorial Pacific Ocean has been lingering from 2014 to 2015, and now strong warming is developing in the eastern equatorial Pacific, the question is whether in 2015 we're going to see a combined impact."

Gierach has a wait-and-see attitude. "All bets are off," she said. "Ocean conditions before the 2015 El Niño make it unclear as to what impacts we can expect. I feel like this one is an entirely different entity."

Patzert notes that what matters to anyone is not overall consequences but local ones. "From day to day, the real impacts of El Niño will be individual storms. At this point, there is a wide range of possibilities. Nobody is predicting a specific mudslide here or there. Weather always does surprise you."

For more information and study visit NASA Earth Science: http://science.nasa.gov/earth-science/ and http://www.jpl.nasa.gov/

Images (mentioned), Animation (mentioned), Text, Credits: NASA/JPL/Alan Buis, written by Carol Rasmussen.

Greetings, Orbiter.ch

jeudi 19 novembre 2015

NASA Selects New Technologies for Parabolic Flights and Suborbital Launches











NASA - National Aeronautics and Space Administration logo.

Nov. 19, 2015

NASA's Flight Opportunities Program has selected eight space technology payloads for reduced gravity flights on board specialized aircraft and commercial suborbital reusable launch vehicles (sRLVs). These flights provide a valuable platform to mature cutting-edge technologies, validating feasibility and reducing technical risks and costs before infusion into future space missions.

Five of the newly selected proposals requested parabolic flights, which involve a flight maneuver that uses a dramatic half-minute drop of the aircraft though the sky to simulate weightlessness. Two proposed projects will fly on sRLVs for testing during longer periods of weightlessness. An additional payload will fly on both platforms. 



(Click on the image for enlarge)

Selected for parabolic flights on aircraft are:

- “Zero Gravity Mass Measurement Device Parabolic Flight Test” - John Wetzel, principal investigator, Orbital Technologies Corporation, Madison, Wisconsin.

- “Evaluation of the Biosleeve Gesture Control Interface for Telerobotics in Microgravity” –  Christopher Assad, principal investigator, Jet Propulsion Laboratory, Pasadena, California.

- “Flight Demonstration of a Gravity-Insensitive, Microchannel Membrane Phase Separator” - Weibo Chen, principal investigator,  Creare Inc., Hanover, New Hampshire.

- “PRIME-4.0: Miniaturized and Reusable Asteroid Regolith Microgravity Experiment for Suborbital and Orbital Use” - Josh Colwell, principal investigator, University of Central Florida,  Orlando, Florida.

- “Testing of a Novel IVA (Intra-Vehicular Activity) Space Suit” - Ted Southern, principal investigator, Final Frontier Design, LLC, Brooklyn, New York.

- “Evolved Medical Microgravity Suction Device” - Charles Cuttino, principal investigator, Orbital Medicine, Inc., Midlothian, Virginia.

Selected for flights on sRLVs are:

- “Suborbital Evaluation of an Aqueous Immersion Surgical System for Reduced Gravity” - George Pantalos, principal investigator, University of Louisville, Louisville, Kentucky.

“Suborbital Particle Aggregation and Collision Experiment-2 (SPACE-2)” - Julie Brisset, principal investigator, University of Central Florida, Orlando, Florida.

- “Evolved Medical Microgravity Suction Device” - Charles Cuttino, principal investigator, Orbital Medicine, Inc., Midlothian, Virginia.

The selectees’ experiments are expected to take to the skies in 2016 and 2017 on flights with U.S. commercial providers arranged by the proposers. The selected proposals requested parabolic flights from Integrated Spaceflight Services, Inc. and ZeroG Corporation. Suborbital reusable launch vehicle flights were requested from Blue Origin, EXOS Aerospace Systems & Technologies and Virgin Galactic.

This selection was made through the agency’s Space Technology Mission Directorate Research, Development, Demonstration and Infusion (REDDI) announcement adding to more than 160 payloads that NASA has chosen for test flights through the Flight Opportunities Program.

The Flight Opportunities Program seeks to advance space technology to meet future mission needs through flight activities that foster the growth of the U.S. commercial spaceflight industry and workforce. NASA will pay for the integration and flight costs for the selected payloads, and limited funds will be provided for other costs to facilitate the flight readiness of these payloads. The next REDDI Flight Opportunities call for proposals will be released in early 2016.

The Flight Opportunities Program, part of NASA's Space Technology Mission Directorate, is managed at NASA's Armstrong Flight Research Center at Edwards, California.  NASA's Ames Research Center at Moffett Field, California, manages the solicitation and selection of technologies to be tested and demonstrated on commercial flight vehicles.

For more information on NASA’s Flight Opportunities Program, visit:

http://www.nasa.gov/directorates/spacetech/flight_opportunities/index.html

Images, Text, Credits: NASA/Ames Research Center/Kimberly Williams/Armstrong Flight Research Center/Leslie Williams.

Greetings, Orbiter.ch

NASA’s STEREO-A Resumes Normal Operations












NASA - STEREO Mission logo.

Nov. 19, 2015

On Nov. 9, 2015, NASA’s Solar and Terrestrial Relations Observatory Ahead, or STEREO-A, once again began transmitting data at its full rate. For the previous year, STEREO-A was transmitting only a weak signal—or occasionally none at all—due to its position almost directly behind the sun. Subsequently, as of Nov. 17, STEREO resumed its normal science operations, which includes transmission of lower-resolution real-time data—used by scientists to monitor solar events—as well as high-definition, but delayed, images of the sun’s surface and atmosphere.

STEREO spacecraft. Image Credit: NASA

One of the key components of the real-time data, known as beacon data, is what's called coronagraph imagery – in which the bright light of the sun is blocked out in order to better see the sun's faint atmosphere. Coronagraphs are key for monitoring when the sun erupts with a coronal mass ejection, which can send a giant cloud of solar material out into space. Such space weather can lead to interference with radio communications, GPS signals and satellites.

“STEREO-A’s real-time data is key for scientists to make accurate models of interplanetary space weather,” said Yari Collado-Vega, a space scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Having a second set of coronagraph images, in addition to those from the Solar and Heliospheric Observatory (SOHO), means we can measure coronal mass ejections much more accurately.”

For the past year, however, beacon data was only received for a few hours each day—if at all—limiting scientists’ ability to monitor the sun. Since August 2014, our line of communication to the spacecraft was so close to the sun that pointing the antenna straight at Earth also meant pointing it nearly directly at the sun, which would cause the spacecraft’s antenna to dangerously overheat. Now that STEREO-A has emerged from behind the sun, scientists have once again pointed the main lobe of STEREO-A’s antenna towards Earth and the stronger signal means that the majority of the beacon data can once again be picked up.


Image above: An image of the sun taken with the Extreme Ultraviolet Imager aboard STEREO-A, which collects images in several wavelengths of light that are invisible to the human eye. This image shows the sun in wavelengths of 195 angstroms, which are typically colorized in green. Image Credits: NASA/STEREO.

STEREO-A is also using this stronger signal to send high-definition views of the sun’s far side with a two- to three-day delay. These detailed images of the sun’s surface and atmosphere allow scientists to better track the formation of solar events.  

“We’re now using STEREO-A to its fullest capabilities, given how far away it is,” said Terry Kucera, deputy project scientist for the STEREO mission at Goddard.

STEREO-A’s twin spacecraft, STEREO Behind, has been out of communication since October 2014, when communications were lost following a planned reset of the spacecraft. For several months, STEREO-B’s orbit took it behind the sun from our perspective, making it impossible to send messages to the spacecraft. But STEREO-B will soon emerge from the sun’s interference zone, and spacecraft operators will resume their attempts to contact the spacecraft on Nov. 30.

Related link:


NASA's STEREO website: http://www.nasa.gov/mission_pages/stereo/main/index.html

Images (mentioned), Text, Credits: NASA’s Goddard Space Flight Center/Sarah Frazier/Rob Garner.

Greetings, Orbiter.ch

A witness to a wet early Mars












ESA - Mars Express Mission patch.

19 November 2015

Aurorae Chaos and Ganges Chasma

Vast volumes of water once flooded through this deep chasm on Mars that connects the ‘Grand Canyon’ of the Solar System – Valles Marineris – to the planet’s northern lowlands.

The image, taken by ESA’s Mars Express on 16 July, focuses on Aurorae Chaos, close to the junction of Ganges, Capri and Eos Chasmata.

Aurorae Chaos measures roughly 710 km across (a smaller section is shown here) and plunges some 4.8 km below the surrounding terrain.

 Aurorae Chaos and Ganges Chasma in context

The region is rich in features pointing to wet episodes in the history of the Red Planet. Dominating the southern (left) portion of the scene are numerous jumbled blocks – ‘chaotic terrain’, believed to form when the surface collapses in response to melting of subsurface ice and the subsequent sudden release of water.

Towards the centre of the image is the smoother floor of Ganges Chasma, comprising mostly alluvial deposits, and which transitions into a steep scarp and a cratered plateau to the north (right).

 Perspective view in Aurorae Chaos / Ganges Chasma

The northern plateau shares the same elevation as that on the southern side, but does not exhibit similar levels of catastrophic collapse.

However, the cliff tops display small channels and the walls show evidence of slumped material or landslides – best seen in the perspective view. Material closest to the main chasma floor appears stepped, which could reflect different water or ice levels over time.

 Aurorae Chaos and Ganges Chasma topography

Another interesting feature can be seen towards the upper centre and to the left in the main images, where a pair of faults cuts through a collapsed block, and perhaps extends into the southern plateau at the top of the image.

The faults could be the result of a tectonic event that occurred after the formation of the chaotic terrain, or they could be from simple subsidence.

Aurorae Chaos and Ganges Chasma in 3D

This region is just a small subsection of a huge system of interconnected valleys and flood channels that emptied water into the northern plains, and which were most likely active in the first 1–2 billion years of Mars’ history.

Related links:

Looking at Mars: http://www.esa.int/Our_Activities/Space_Science/Mars_Express

More about...

Mars Express overview: http://www.esa.int/Our_Activities/Space_Science/Mars_Express_overview

Mars Express 10 year brochure: http://esamultimedia.esa.int/multimedia/publications/BR-312/

Images, Text, Credits: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO/NASA MGS MOLA Science Team.

Greetings, Orbiter.ch

mercredi 18 novembre 2015

SDO Sees Brightening Magnetic Loops












NASA - Solar Dynamics Observatory (SDO) patch.

Nov. 18, 2015


Two active regions sprouted arches of bundled magnetic loops in this video from NASA’s Solar Dynamics Observatory taken on Nov. 11-12, 2015. Charged particles spin along the magnetic field, tracing out bright lines as they emit light in extreme ultraviolet wavelengths.

video
SDO Sees Brightening Magnetic Loops

About halfway through the video, a small eruption from the active region near the center causes the coils to rise up and become brighter as the region re-organizes its magnetic field. This video was taken in extreme ultraviolet wavelengths of 171 angstroms, typically invisible to our eyes but colored here in gold.

For more information about Solar Dynamics Observatory (SDO), visit: http://www.nasa.gov/mission_pages/sdo/main/index.html

Image, Video, Text, Credits: NASA/SDO/Goddard Space Flight Center/Steele Hill/Sarah Frazier/Rob Garner.

Greetings, Orbiter.ch

Upgraded nuclear physics facility starts up












CERN - European Organization for Nuclear Research logo.

November 18, 2015

Over the last few weeks, CERN's nuclear physics facility, ISOLDE, has been producing ion beams at higher energies. The first cryomodule of the new HIE-ISOLDE (High-Intensity and Energy ISOLDE) accelerator is up and running, increasing the beam energy from 3 to 4.3 MeV per nucleon.


Image above: The ISOLDE beamline, equipped with the first HIE-ISOLDE cryomodule in its light grey cryostat. Image Credit: CERN.

The unique ISOLDE facility accelerates different types of radioactive ions for many fields of fundamental and applied research. Each year, its beams are used by around fifty experiments studying a wide range of subjects from the properties of atoms and nuclei to biomedical applications, nuclear astrophysics and solid-state physics. By producing higher-energy beams, the HIE-ISOLDE accelerator will increase the research opportunities further.

These first beams are the result of eight years of development and manufacturing. The assembly of this first cryomodule presented CERN’s teams with numerous technical challenges. It contains five accelerating cavities and a solenoid magnet that focuses the beam, all of which are superconducting. The cavities were particularly complex to build, and the cryomodule is made up of no fewer than 10 000 components! It was transported to the ISOLDE hall on 2 May and coupled to the existing accelerator. The commissioning began in the summer, culminating in the acceleration of the first radioactive beam on 22 October.

video
HIE-ISOLDE: Nuclear Physics Now at Higher Energies

HIE-ISOLDE will run for a total of five weeks this year. Next year, another cryomodule will be coupled to the first, increasing the energy to 5.5 MeV per nucleon. The assembly of the final two cryomodules will begin in mid-2016, bringing the final energy to 10 MeV per nucleon for the heaviest nuclei available at ISOLDE.

Read the full article in the CERN Bulletin: http://cds.cern.ch/journal/CERNBulletin/2015/47/News%20Articles/2065714?ln=en

Note:

CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 22 Member States.

Related link:

CERN's nuclear physics facility ISOLDE: http://home.web.cern.ch/about/experiments/isolde

For more information about European Organization for Nuclear Research (CERN), Visit: http://home.cern/

Image (mentioned), Video, Text, Credits: CERN/Corinne Pralavorio.

The Birth of Monsters












ESO - European Southern Observatory logo.

November 18, 2015

VISTA pinpoints earliest giant galaxies

Massive galaxies discovered in the early Universe

ESO’s VISTA survey telescope has spied a horde of previously hidden massive galaxies that existed when the Universe was in its infancy. By discovering and studying more of these galaxies than ever before, astronomers have, for the first time, found out exactly when such monster galaxies first appeared.

Just counting the number of galaxies in a patch of sky provides a way to test astronomers’ theories of galaxy formation and evolution. However, such a simple task becomes increasingly hard as astronomers attempt to count the more distant and fainter galaxies. It is further complicated by the fact that the brightest and easiest galaxies to observe — the most massive galaxies in the Universe — are rarer the further astronomers peer into the Universe’s past, whilst the more numerous less bright galaxies are even more difficult to find.

A team of astronomers, led by Karina Caputi of the Kapteyn Astronomical Institute at the University of Groningen, has now unearthed many distant galaxies that had escaped earlier scrutiny. They used images from the UltraVISTA survey, one of six projects using VISTA to survey the sky at near-infrared wavelengths, and made a census of faint galaxies when the age of the Universe was between just 0.75 and 2.1 billion years old.

Massive galaxies discovered in the early Universe

UltraVISTA has been imaging the same patch of sky, nearly four times the size of a full Moon, since December 2009. This is the largest patch of sky ever imaged to these depths at infrared wavelengths. The team combined these UltraVISTA observations with those from the NASA Spitzer Space Telescope, which probes the cosmos at even longer, mid-infrared wavelengths [1].

“We uncovered 574 new massive galaxies — the largest sample of such hidden galaxies in the early Universe ever assembled,” explains Karina Caputi. “Studying them allows us to answer a simple but important question: when did the first massive galaxies appear?”

Imaging the cosmos at near-infrared wavelengths allowed the astronomers to see objects that are both obscured by dust, and extremely distant [2], created when the Universe was just an infant.

The team discovered an explosion in the numbers of these galaxies in a very short amount of time. A large fraction of the massive galaxies [3] we now see around us in the nearby Universe were already formed just three billion years after the Big Bang.

“We found no evidence of these massive galaxies earlier than around one billion years after the Big Bang, so we’re confident that this is when the first massive galaxies must have formed,” concludes Henry Joy McCracken, a co-author on the paper [4].

video
Massive galaxies discovered in the early Universe

In addition, the astronomers found that massive galaxies were more plentiful than had been thought. Galaxies that were previously hidden make up half of the total number of massive galaxies present when the Universe was between 1.1 and 1.5 billion years old [5]. These new results, however, contradict current models of how galaxies evolved in the early Universe, which do not predict any monster galaxies at these early times.

To complicate things further, if massive galaxies are unexpectedly dustier in the early Universe than astronomers predict then even UltraVISTA wouldn’t be able to detect them. If this is indeed the case, the currently-held picture of how galaxies formed in the early Universe may also require a complete overhaul.

The Atacama Large Millimeter/submillimeter Array (ALMA) will also search for these game-changing dusty galaxies. If they are found they will also serve as targets for ESO’s 39-metre European Extremely Large Telescope (E-ELT), which will enable detailed observations of some of the first ever galaxies.

Notes:

[1] ESO’s VISTA telescope observed in the near-infrared wavelength range 0.88–2.15 μm while Spitzer performed observations in the mid-infrared at 3.6 and 4.5 μm.

[2] The expansion of space means that the more distant a galaxy is, the faster it appears to be speeding away from an observer on Earth. This stretching causes the light from these distant objects to be shifted into redder parts of the spectrum, meaning that observations in the near-to-mid infrared are necessary to capture the light from these galaxies.

[3] In this context, "massive" means more than 50 billion times the mass of the Sun. The total mass of the stars in the Milky Way is also close to this figure.

[4] The team found no evidence of massive galaxies beyond a redshift of 6, equivalent to times less than 0.9 billion years after the Big Bang.

[5] This is equivalent to redshifts between z=5 and z=4.

More information:

This research was presented in a paper entitled “Spitzer Bright, UltraVISTA Faint Sources in COSMOS: The Contribution to the Overall Population of Massive Galaxies at z = 3-7”, by K. Caputi et al., which appeared in the Astrophysical Journal.

The team is composed of Karina I. Caputi (Kapteyn Astronomical Institute, University of Groningen, Netherlands), Olivier Ilbert (Laboratoire d'Astrophysique de Marseille, Aix-Marseille University, France), Clotilde Laigle (Institut d'Astrophysique de Paris, France), Henry J. McCracken (Institut d'Astrophysique de Paris, France), Olivier Le Fèvre (Laboratoire d'Astrophysique de Marseille, Aix-Marseille University, France), Johan Fynbo (Dark Cosmology Centre, Niels Bohr Institute, Copenhagen, Denmark), Bo Milvang-Jensen (Dark Cosmology Centre), Peter Capak (NASA/JPL Spitzer Science Centre, California Institute of Technology, Pasadena, California, USA), Mara Salvato (Max-Planck Institute for Extragalactic Physics, Garching, Germany) and Yoshiaki Taniguchi (Research Center for Space and Cosmic Evolution, Ehime University, Japan).

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

Links:

Research Paper in the Astrophysical Journal: http://www.eso.org/public/archives/releases/sciencepapers/eso1545/eso1545a.pdf

Photos of VISTA: http://www.eso.org/public/images/archive/search/?adv=&subject_name=Visible%20and%20Infrared%20Survey%20Telescope%20for%20Astronomy

VISTA Public Surveys: https://www.eso.org/public/teles-instr/surveytelescopes/vista/surveys/

Related links:

Kapteyn Astronomical Institute: http://www.rug.nl/research/kapteyn/?lang=en

NASA Spitzer Space Telescope: http://www.spitzer.caltech.edu/

Atacama Large Millimeter/submillimeter Array (ALMA): http://www.eso.org/public/teles-instr/alma/

European Extremely Large Telescope (E-ELT): http://eso.org/e-elt

Images, Video, Text, Credits: ESO/Richard Hook/UltraVISTA team. Acknowledgement: TERAPIX/CNRS/INSU/CASU/Music: Johan Monell (www.johanmonell.com).

Best regards, Orbiter.ch

mardi 17 novembre 2015

Lunokhod-1 first on the surface of the Earth satellite












Lunokhod-1 Soviet propaganda poster.

11/17/2015

Lunokhod-1

November 17, 1970 the Soviet self-propelled machine Lunokhod-1 paved the first track on the lunar surface. A new stage in the study of Earth's natural satellite by automatic machines.

Lunokhod-1 Panoramas

Given the short time of a radio signal to the moon and back, 2.5 seconds, the control system Lunokhod was decided to make the distance, that is, commands from Earth. The crew of the lunar rover had before Videocontrol devices - monitors, which displays information about the state of telemetry systems rover, as well as the television image of the lunar surface. To work operators have set up special boards fitted with control knobs on the type of those having a manned spacecraft. Any change in the position of the handle is automatically converted into commands that the NPC through the antenna 10 were transferred to the rover.

Lunokhod-1 operator from control center on Earth
 
Lunokhod-1 conducted research on the surface of the moon and near-moon space until 30 September 1971. The total duration of the active functioning of the self-propelled machine Lunokhod-1 was 301 hours 37 minutes running. The unit was roll on the moon 10'540 meters, which was a world record, transmitted to Earth 211 lunar panoramas, 25 thousand photographs and other research results.

 NASA LRO Image: Lunokhod-1 Rover Parked On The Lunar Surface

"Lunokhod-1" has been created in the design office Khimki Machine Building Plant named after S. Lavochkin under the direction of Gregory N. Babakina. The self-propelled chassis for Lunokhod was created in VNIITransmash led by Alexander Leonovich Kemurdzhiana.

ROSCOSMOS Press Release: http://www.federalspace.ru/21842/

Images, Text, Credits: ROSCOSMOS/NPO Lavochkin/Russian Academy of Sciences/NASA/Translation: Orbiter.ch Aerospace.

Best regards, Orbiter.ch

ROSCOSMOS - The successful launch of Soyuz-2.1b












ROSCOSMOS logo.

11/17/2015

Soyuz-2.1b rocket on the launch-pad 43

November 17, 2015 at 09:33 minutes MSK (06:33 UTC) from launch pad 43 State Test Cosmodrome Russian Defense Ministry (Plesetsk Cosmodrome) to Start a space rocket program Soyuz-2.1b launches secret spacecraft for the interests of the Russian Defense Ministry. Running made joint to specialists of Roscosmos, enterprises of space industry and the Defense Ministry of Russia. The launch of the rocket Soyuz-2.1b was occurred normally.

video
Soyuz-2.1b rocket launches secret Russian army spacecraft 

The upper stage "Fregat" brought the spacecraft into its target orbit. Carrier rocket Soyuz-2.1b created in FSUE "GNPRKTs "Samara Space Center", is a modification of  Soyuz-2 . Compared to option "1a" this rocket has an engine with increased power characteristics in the third stage. At the Soyuz-2.1b with respect to the previous version more accurate clearance, stability and control, increased payload mass.

The upper stage "Fregat" evolution

The upper stage "Fregat" developed by NPO. Lavochkin spacecraft to remove various purposes as part of the upgraded and existing PH. The upper stage can significantly improve the energy performance and pH. Using block "Fregat" makes possible the removal of spacecraft on almost any given orbit of satellites and on interplanetary trajectories.

ROSCOSMOS Press Release: http://www.federalspace.ru/21841/

Images, Video, Text, Credits: ROSCOSMOS/NPO. Lavochkin/Translation: Orbiter.ch Aerospace.

Greetings, Orbiter.ch

A Brighter Moon












NASA - Cassini Mission to Saturn patch.

Nov. 17, 2015


Although Dione (near) and Enceladus (far) are composed of nearly the same materials, Enceladus has a considerably higher reflectivity than Dione. As a result, it appears brighter against the dark night sky.

The surface of Enceladus (313 miles or 504 kilometers across) endures a constant rain of ice grains from its south polar jets. As a result, its surface is more like fresh, bright, snow than Dione's (698 miles or 1123 kilometers across) older, weathered surface. As clean, fresh surfaces are left exposed in space, they slowly gather dust and radiation damage and darken in a process known as "space weathering."

This view looks toward the leading hemisphere of Enceladus. North on Enceladus is up and rotated 1 degree to the right. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on Sept. 8, 2015.

The view was acquired at a distance of approximately 52,000 miles (83,000 kilometers) from Dione. Image scale is 1,600 feet (500 meters) per pixel. The distance from Enceladus was 228,000 miles (364,000 kilometers) for an image scale of 1.4 miles (2.2 kilometers) per pixel.

The Cassini mission is a cooperative project of NASA, ESA (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 mission for NASA's Science Mission Directorate, Washington. 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, Colorado.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov or http://www.nasa.gov/cassini . The Cassini imaging team homepage is at http://ciclops.org and http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens

Image, Text, Credits: NASA/JPL-Caltech/Space Science Institute/Tony Greicius.

Greetings, Orbiter.ch

Cool New Batteries for Solar Impulse











SolarImpulse - Around the World patch.

November 17, 2015

After several months of designing and testing, it’s now time to get Solar Impulse back on its feet! And to avoid the batteries overheating again, our engineers have upgraded the whole battery system and integrated a cooling system. Take a look at how and when the repair work will take place to get the plane ready for part 2 of the round the world tour.

As you may have heard, Solar Impulse has been hangared in Hawaii since July – not the worst place to be stranded we reckon – because its batteries overheated during the 5-day and night record breaking flight from Nagoya, Japan. Since the plane had been exposed to harsh weather conditions from Nanjing to Nagoya, we decided to do a test flight before leaving for Hawaii. Having to perform a test flight followed by a mission flight had not been taken into account in the design process of the battery system, which did not allow the batteries to cool down in between the two.

Technicians carrying out maintenance work on the batteries in Hawaii in July

But the show must go on, and for the plane to be back in the air by April 2016, our technical team still has a lot on its plate. Why wait until spring? Because the days are longer, which means more daylight hours to recharge the batteries during flight periods.

Let’s remember that we are at the limits of technology: each morning the charge goes down to 10% of battery capacity.

Imagine how you feel when you realize that the battery level of your cell phone is red and that you only have a few minutes left before it shuts down! The first batch of upgraded elements, five in total (four to replace the plane’s damaged ones, and one for testing), is currently under construction. The second one, the four spare parts, will be hatched beginning of 2016.

Let’s take a look at the planning concerning the first round. The three types of elements are designed separately and then mounted together before being integrated into the aircraft.


1. The key components, the batteries, have been produced by our supplier Kokam, and are now on their way to Germany to be tested, assembled, and placed in their boxes. They are similar to the former ones.

Battery dummy cells made out of aluminum sheet metal for thermal tests

2. In parallel, the battery containers, are being built and undergoing shock testing in Dübendorf, Switzerland. They will be ready at the end of November, and the batteries will thus be encapsulated in December. Like the previous ones, they contain silver (a good electrical conductor), but the novelty lies in a fail-safe system which should safeguard us from anymore temperature-related glitches in case we have to follow a different mission profile than the one foreseen. It can be controlled from the cockpit and includes a cooling and backup system. In case the cooling system breaks down, the backup one steps in and allows the pilot to control the opening so that it doesn’t stay completely open, which would cause freezing, or closed, leading to another overheating scenario. Indeed, this could "Jeopardise" the continuation of the flight which would be critical if the airplane was flying over an ocean.

Structural load test of the new battery box: 1000 kg towards the ground, 370 kg to the side

3. The last level is the engine housing (or gondola), which shelters both battery and engine, seeing as the former powers the latter at night. A few adjustments concerning the electronics have been made and an air vent has been added to let air flow into the battery’s cooling system. The gondolas are also currently being pieced together in Dübendorf, by our hard working engineers and technicians.

Air inlet on gondola front part for the new battery cooling system

And for now, you can give the world leaders a hand by voting here for the solutions to tackle climate change you think most efficient. We will take the most popular ones to the UN climate conference COP21: http://www.futureisclean.org/solutions?utm_source=blog&utm_medium=banner&utm_content=batteries&utm_campaign=solutions

For more information about Solar Impulse Around the World, visit: http://www.solarimpulse.com/

Images, Text, Credit: SolarImpulse.

Greetings, Orbiter.ch

lundi 16 novembre 2015

NASA's Curiosity Mars Rover Heads Toward Active Dunes












NASA - Mars Science Laboratory  (MSL) patch.

Nov. 16, 2015


Image above: This Sept. 25, 2015, view from the Mast Camera on NASA's Curiosity Mars rover shows a dark sand dune in the middle distance. Image Credits: NASA/JPL-Caltech/MSSS.

On its way to higher layers of the mountain where it is investigating how Mars' environment changed billions of years ago, NASA's Curiosity Mars rover will take advantage of a chance to study some modern Martian activity at mobile sand dunes.

In the next few days, the rover will get its first close-up look at these dark dunes, called the "Bagnold Dunes," which skirt the northwestern flank of Mount Sharp. No Mars rover has previously visited a sand dune, as opposed to smaller sand ripples or drifts. One dune Curiosity will investigate is as tall as a two-story building and as broad as a football field. The Bagnold Dunes are active: Images from orbit indicate some of them are migrating as much as about 3 feet (1 meter) per Earth year. No active dunes have been visited anywhere in the solar system besides Earth.


Image above: The dark band in the lower portion of this Martian scene is part of the "Bagnold Dunes" dune field lining the northwestern edge of Mount Sharp. Image Credits: NASA/JPL-Caltech/MSSS.

"We've planned investigations that will not only tell us about modern dune activity on Mars but will also help us interpret the composition of sandstone layers made from dunes that turned into rock long ago," said Bethany Ehlmann of the California Institute of Technology and NASA's Jet Propulsion Laboratory, both in Pasadena, California.

As of Monday, Nov. 16, Curiosity has about 200 yards or meters remaining to drive before reaching "Dune 1." The rover is already monitoring the area's wind direction and speed each day and taking progressively closer images, as part of the dune research campaign. At the dune, it will use its scoop to collect samples for the rover's internal laboratory instruments, and it will use a wheel to scuff into the dune for comparison of the surface to the interior.

Curiosity has driven about 1,033 feet (315 meters) in the past three weeks, since departing an area where its drill sampled two rock targets just 18 days apart. The latest drilled sample, "Greenhorn," is the ninth since Curiosity landed in 2012 and sixth since reaching Mount Sharp last year. The mission is studying how Mars' ancient environment changed from wet conditions favorable for microbial life to harsher, drier conditions.


Image above: This view taken from orbit around Mars shows the sand dune that will be the first to be visited by NASA's Curiosity Mars Rover along its route to higher layers of Mount Sharp. Image Credits: NASA/JPL-Caltech/Univ. of Arizona.

Before Curiosity's landing, scientists used images from orbit to map the landing region's terrain types in a grid of 140 square quadrants, each about 0.9 mile (1.5 kilometers) wide. Curiosity entered its eighth quadrant this month. It departed one called Arlee, after a geological district in Montana, and drove into one called Windhoek, for a geological district in Namibia. Throughout the mission, the rover team has informally named Martian rocks, hills and other features for locations in the quadrant's namesake area on Earth. There's a new twist for the Windhoek Quadrant: scientists at the Geological Society of Namibia and at the Gobabeb Research and Training Center in Namibia have provided the rover team with a list of Namibian geological place names to use for features in this quadrant. The Windhoek theme was chosen for this sand-dune-bearing quadrant because studies of the Namib Desert have aided interpretation of dune and playa environments on Mars.


Animation above: This animation flips back and forth between views taken in 2010 and 2014 of a Martian sand dune at the edge of Mount Sharp, documenting dune activity. Animation Credits: NASA/JPL-Caltech/Univ. of Arizona.

What distinguishes actual dunes from windblown ripples of sand or dust, like those found at several sites visited previously by Mars rovers, is that dunes form a downwind face steep enough for sand to slide down. The effect of wind on motion of individual particles in dunes has been studied extensively on Earth, a field pioneered by British military engineer Ralph Bagnold (1896-1990). Curiosity's campaign at the Martian dune field informally named for him will be the first in-place study of dune activity on a planet with lower gravity and less atmosphere.

Observations of the Bagnold Dunes with the Compact Reconnaissance Imaging Spectrometer on NASA's Mars Reconnaissance Orbiter indicate that mineral composition is not evenly distributed in the dunes. The same orbiter's High Resolution Imaging Science Experiment has documented movement of Bagnold Dunes.

"We will use Curiosity to learn whether the wind is actually sorting the minerals in the dunes by how the wind transports particles of different grain size," Ehlmann said.


Image above: This map shows the route driven by NASA's Curiosity Mars rover from the location where it landed in August 2012 to its location in mid-November 2015, approaching examples of dunes in the "Bagnold Dunes" dune field. Image Credits: NASA/JPL-Caltech/Univ. of Arizona.

As an example, the dunes contain olivine, a mineral in dark volcanic rock that is one of the first altered into other minerals by water. If the Bagnold campaign finds that other mineral grains are sorted away from heavier olivine-rich grains by the wind's effects on dune sands, that could help researchers evaluate to what extent low and high amounts of olivine in some ancient sandstones could be caused by wind-sorting rather than differences in alteration by water.

Ehlmann and Nathan Bridges of the Johns Hopkins University's Applied Physics Laboratory, Laurel, Maryland, lead the Curiosity team's planning for the dune campaign.

"These dunes have a different texture from dunes on Earth," Bridges said. "The ripples on them are much larger than ripples on top of dunes on Earth, and we don't know why. We have models based on the lower air pressure. It takes a higher wind speed to get a particle moving. But now we'll have the first opportunity to make detailed observations."

JPL, managed by Caltech for NASA, built Curiosity and manages the project for NASA's Science Mission Directorate in Washington. For more information about Curiosity, visit:

http://www.nasa.gov/msl

http://mars.jpl.nasa.gov/msl/

You can follow the mission on Facebook and Twitter at:

http://www.facebook.com/marscuriosity

http://www.twitter.com/marscuriosity

Images (mentioned), Text, Credits: NASA/Dwayne Brown/Laurie Cantillo/JPL/Guy Webster/Martin Perez.

Best regards, Orbiter.ch