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Sonntag, 8. März 2015 - 15:30 Uhr

Raumfahrt - China startet Tianzhou-1 Frachtschiff im Jahr 2016 für Rendezvous mit Weltraumlabor

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China will send a cargo ship into the space in 2016 to dock with a future space module scheduled to be launched earlier the same year, a leading Chinese space scientist said Friday.
The Tianzhou-1, which literally means "heavenly vessel", will carry propellants, living necessities for astronauts, research facilities and repair equipment to China's second orbiting space lab Tiangong-2, said Zhou Jianping, chief engineer of China's manned space program.
Cargo transportation system is a key technology China must master and make breakthroughs to build its own space station, said Zhou who is also a member of the National Committee of the Chinese People's Political Consultative Conference, the country's top political advisory body.
China's multi-billion-dollar space program, a source of surging national pride in the country, aims to put a permanent manned space station into service around 2022.
The country already launched its first space lab, Tiangong-1, in September 2011 and has conducted two dockings with the module in the following two years. In June 2013, three Chinese astronauts delivered a physics lesson onboard Tiangong-1.
According to Zhou, Tianzhou-1 will be blasted off on top of a next-generation Long March-7 rocket, possibly from a new launch site in the southern Hainan Province.
Research on the Long March-5 carrier rocket - to be used to lift the Tiangong-2 lab into space - Tiangong-2's payload, and selection of astronauts for the mission are currently "progressing in an orderly manner," Zhou said.
Quelle: Xinhua
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China has ability but no plan for manned lunar mission: expert
The world's third country to softland on the moon has the ability to achieve the manned lunar landing but it has no plan to do it, a leading Chinese space scientist said Friday.
"With China's current technologies of manned space flight and moon probe, we have the technology basis to realize the manned lunar mission," said Zhou Jianping, chief designer of China's manned space program.
But the scientist said his nation has no plan to land its astronauts on the moon for the time being.
Zhou, a member of the Chinese People's Political Consultative Conference National Committee, the country's top political advisory body, also said that challenges and a lot of preparation precede the realization of the manned lunar mission.
For example, it requires the research and development of a bigger carrier rocket and the bigger and more sophisticated manned spacecraft, he added.
The Chang'e-3 lunar probe, composed of a lander and China's first moon rover, named "Yutu," soft-landed on the moon in 2013, making China the third country to carry out such a mission after the United States and the Soviet Union.
Quelle: Xinhua
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Update: 8.03.2015
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China's test spacecraft simulates orbital docking
China has run tests close to the moon simulating an unmanned docking procedure needed in the country's next lunar mission.
The service module of the unmanned lunar orbiter currently in space to trial such techniques entered a target lunar orbit after breaking maneuvers, and flew to a suitable position for orbital docking between Tuesday and Saturday, said the State Administration of Science, Technology and Industry for National Defense (SASTIND) on Sunday.
Liu Jizhong, deputy chief commander of the SASTIND's lunar probe project, said that the service module has proven the reliability of key technology needed for the docking of two spacecraft in the Chang'e-5 mission.
The Chang'e-5 probe, expected to launch in 2017, will be tasked with landing on the moon, collecting samples and returning to Earth.
The current lunar orbiter was launched on Oct. 24, 2014. A capsule designed to separate and return to Earth did so as planned in November, while the service module continues its lunar flight to carry out preset scientific tasks.
The service module is operating smoothly and will carry out further tests on capturing lunar images, and may conduct tests assessing lunar gravity depending how the mission progresses.
Liu told Xinhua that the SASTIND expects to test launching Chang'e-5 with a Long March-5 carrier rocket in south China's Hainan Province this year.
"In the tests of the service module, we have simulated three key procedures needed for Chang'e-5: re-entry [to the moon's orbit] at high speed, adjustment of lunar orbit and docking in lunar orbit, laying a solid foundation for China's three-step lunar program -- orbiting, landing and returning," said Liu.
Quelle: Xinhua

Tags: Raumfahrt 

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Sonntag, 8. März 2015 - 15:11 Uhr

Astronomie-History - Kosmos 1928: Astronomische Stereobilder

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Aus dem CENAP-Archiv

 

Quelle: Kosmos / CENAP-Archiv.


Tags: Astronomie 

1743 Views

Sonntag, 8. März 2015 - 12:15 Uhr

Astronomie - Subaru Teleskop beobachtet Schnelle Änderungen von Komet C / 2013 R1 (Lovejoy) Plasma Schweif

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Images from a December 2013 observation of the comet C/2013 R1 (Lovejoy) (Note 1) reveal clear details about rapidly changing activity in that comet's plasma tail. To get this image, astronomers used Subaru Telescope's wide-field prime-focus Suprime-Cam to zero in on 0.8 million kilometers of the comet's plasma tail, which resulted in gaining precious knowledge regarding the extreme activity in that tail as the comet neared the Sun. Their results are reported this week in a paper in the March 2015 edition of the Astronomical Journal.

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Figure 1:This GIF animation shows changes in the global structure of Comet Lovejoy's (C/2013 R1) plasma tail. There are three, 2-minute exposures taken in the I-band. The image is aligned so that the nucleus of the comet is at the same position and the tail lies vertically. The time stamp at the bottom right shows the start time of each exposure in Hawai'i time on the morning of December 4, 2013. Bright parts of the sky are shown as black, and dark parts are shown as white, allowing astronomers to see details in the object more clearly. The white tilted grid is a gap between CCD detectors. In the image, the tail narrows with time, especially downstream of the nucleus (which is at the bottom of the image). Moreover, two clumps were detected forming formed at about 0.3 million kilometers from the nucleus. They drifted toward downstream about 20 - 25 kilometers per second (Figure 2). (Credit: NAOJ)

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Team of researchers from National Astronomical Observatory of Japan, Stony Brook University (The State University of New York) and Tsuru University reported highly resolved find details of this comet captured in B-band in 2013 (Subaru Telescope's Image Captures the Intricacy of Comet Lovejoy's Tail). They used I-band filter which includes H2O+ line emissions and the V-band filter which includes CO+ and H2O+ line emissions. During the observations, the comet exhibited very rapid changes in its tail in the course of only 20 minutes (Figure 1). Such extreme short-term changes are the result of the comet's interactions with the solar wind, which consists of charged particles constantly sweeping out from the Sun. The reason for the rapidity of these changes is not well understood.
Dr. Jin Koda, the principal investigator of these nights, says "My research is on galaxies and cosmology, so I rarely observe comets. But Lovejoy was up in the sky after my targets were gone on our observing nights, and we started taking images for educational and outreach purposes. The single image from the previous night revealed such delicate details along the tail it inspired us further to take a series of images on the following night. As we analyzed the images, we realized that the tail was displaying rapid motion in a matter of only a few minutes! It was just incredible!"
The plasma tail of a comet forms when gas molecules and atoms coming out from the comet encounter the solar wind. Changes and disturbances in the solar wind can affect the behavior and appearance of this plasma tail, causing it to form clumps of ionized material. The material in the plasma tail departs from the comet's coma and floats away on the solar wind. At these times, the plasma tail can take on a "kinked" or twisted look.
A good candidate for a detailed study of activity in the plasma tail must be a bright comet with an orbit that takes it close enough to the Sun to form such a tail. In addition, the best viewing angles for astronomers to capture views of plasma tail changes occur when the comet also approaches close to Earth. As a result, comets that allow good viewing of the plasma tail are relatively rare - about one or two per year. During its passage, Comet Lovejoy's plasma tail was almost perpendicular (83.5 degrees) to the line of sight from Earth. That made it a prime candidate for close-up observations of its plasma tail structure using Suprime-Cam.
Another discovery is that clumps located in the plasma tail at about 300 thousand kilometers from the nucleus moved at a fairly slow speed -- about 20 - 25 kilometers per second (Figure 2). That is much slower than reported in other comets, such as P/Halley, which gave off clumps that moved as fast as 58 kilometers per second or the value 44 +/- 11 kilometers per second (Note 2) as derived from several bright comets in the past.
The speed of the solar wind ranges from 300 to 700 kilometers per second and the wind intensity and velocity that the comet encounters depends on where it is located with respect to the Sun. The solar wind helps to accelerate the clumps in the tail out away from the Sun. Eventually the clumps in the comet's tail reach this high speed. The observation team thinks they witnessed the beginning of the acceleration of the clumps by the solar wind.
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Figure 2: (left): A 2-second I-band exposure of the comet. The cyan rectangle shows the region in the right panel. (right): This shows movement of two clumps in the plasma tail. Images produced from 2-minute exposures are further processed; background star trails are masked, and unsharp-masked to enhance detailed structures. The masked star trails are seen as short tilted white lines. Time stamps in yellow show the start time of the exposure. White circles indicate the clumps detected in this study. They move away from the nucleus over time. The size of the cutout is about 2500 x 5600 kilometers. From the data, the research team calculated the speed of the clumps at 20 - 25 kilometers per second. (Credit: NAOJ)
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It is still under study how these ion clumps form and what parameters determine the initial speed of them. Dr. Masafumi Yagi, the first author of the paper noted "Comets are often observable only during the twilight as they come near the Sun. On the other hand, it becomes difficult to observe faint objects like galaxies during the twilight hours because of the brighter sky background. Well-designed telescope scheduling like this case makes an effective use of the Subaru Telescope's time and will enable us to collect more data of comets when the opportunity arises in the future."
The team's research paper titled “Initial Speed of Knots in the Plasma Tail of C/2013 R1 (Lovejoy) will be published in Astronomical Journal in its March 2015 issue.
Authors:
Masafumi Yagi (National Astronomical Observatory of Japan)
Jin Koda (Stony Brook University)
Reiko Furusho (National Astronomical Observatory of Japan and Tsuru University)
Tsuyoshi Terai (National Astronomical Observatory of Japan and Subaru Telescope)
Hideaki Fujiwara (Subaru Telescope)
Jun-ichi Watanabe (National Astronomical Observatory of Japan)
Notes:
Comets are generally referred to by designations according to the order of discovery while IAU adopted a guideline that comets are named for the family name of their individual discoverer(s) (guideline by IAU).
There are several bright "comet Lovejoy", which were discovered by Mr. Terry Lovejoy. For example, C/2014 Q2 (Lovejoy), which is still bright at the time of this press release (March 2015) (Jan 16, 2015 Comet Lovejoy Photographed at ALMA OSF, and C/2011 W3 (Lovejoy), which approached the Sun in 2012 Jan 05, 2012 Comet Lovejoy and Southern Cross are different from C/2013 R1 (Lovejoy) in this study.
References
Saito et al. 1987, "Structure and dynamics of the plasma tail of comet P/Halley. I - Knot event on December 31, 1985", Astronomy and Astrophysics, 187, 209.
Niedner 1981, "Interplanetary gas. XXVII - A catalog of disconnection events in cometary plasma tails", Astrophysical Journal Supplement Series, 46, 141.
Quelle: National Astronomical Observatory of Japan and Subaru Telescope

Tags: Astronomie 

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Sonntag, 8. März 2015 - 11:54 Uhr

Astronomie - Der zweite bekannte Fall eines Planeten in einem Vierfach-Sternsystem

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Researchers wanting to know more about the influences of multiple stars on exoplanets have come up with a new case study: a planet in a four-star system.
The discovery was made at Palomar Observatory using two new adaptive optics technologies that compensate for the blurring effects of Earth’s atmosphere: the robotic Robo-AO adaptive optics system, developed under the leadership of Dr. Christoph Baranec of the University of Hawaii at Manoa’s Institute for Astronomy, and the PALM-3000 extreme adaptive optics system, developed by a team at Caltech and NASA’s Jet Propulsion Laboratory (JPL) that also included Baranec.
The newfound four-star planetary system, called 30 Ari, is located 136 light-years away in the constellation Aries. The system’s gaseous planet is enormous, with 10 times the mass of Jupiter, and orbits its primary star every 335 days.
The new study, published in the Astronomical Journal, brings the number of known stars in the 30 Ari system from three to four. This discovery suggests that planets in quadruple star systems might be less rare than once thought.
“About four percent of solar-type stars are in quadruple systems, which is up from previous estimates because observational techniques are steadily improving,” said co-author Andrei Tokovinin of the Cerro Tololo Inter-American Observatory in Chile.
The newly discovered fourth star, whose distance from the planet is 23 times the sun-Earth distance, does not appear to have impacted the orbit of the planet. The exact reason for this is uncertain, so the team is planning further observations to better understand the orbit of the newly discovered star and its complicated family dynamics.
Were it possible to see the skies from this world, the four stars would look like one small sun and two very bright stars that would be visible in daylight. If viewed with a large enough telescope, one would see that one of those bright stars is actually a binary system—two stars orbiting each other.
In recent years, dozens of planetary systems with two or three host stars have been found, including those that would have twin sunsets reminiscent of the ones on the fictional Star Wars planet Tatooine. Finding planets with multiple stars isn’t too much of a surprise, considering that binary stars are more common in our galaxy than single stars such as our sun.
Lead author Lewis Roberts (JPL) and his colleagues want to understand the effects that multiple stars can have on their developing youthful planets. Evidence suggests that stellar companions can influence the fate of planets by changing the planets’ orbits and even triggering some to grow more massive.
The “hot Jupiter” planets that whip around their stars in just days, for example, might be gently nudged closer to their primary star by the gravitational hand of a stellar companion. “This result strengthens the connection between multiple star systems and massive planets,” said Roberts.
“The discovery of this exciting system is only possible when we quickly scan through large numbers of potential targets,” said Baranec. “At the moment, Robo-AO is the only instrument that can give us the necessary combination of resolution and efficiency. Once we discover something interesting with Robo-AO, we can follow up with the ‘Formula 1’ systems, like PALM-3000 or the SCExAO system at the Subaru Telescope in Hawaii, to obtain the absolute sharpest images possible. Additionally, we’re planning to bring a new, more powerful Robo-AO system to the University of Hawaii 2.2-m telescope to leverage the pristine skies of Maunakea, Hawaii. We’ll use it for even larger surveys and follow-up observations of asteroids and supernovae discovered by ATLAS on Mauna Loa and Haleakala.”
ATLAS (Asteroid Terrestrial-impact Last Alert System ) is an asteroid-impact early-warning system being developed by the University of Hawaii with funding from NASA. When completed in 2015, it will consist of two telescopes, one on Mauna Loa and the other on Haleakala, that will automatically scan the whole visible sky several times every night looking for moving objects.
Quelle: Institute for Astronomy at the University of Hawaii at Manoa

Tags: Astronomie 

1959 Views

Sonntag, 8. März 2015 - 11:18 Uhr

Astronomie - Exorings am Horizont

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Astronomers from the Harvard-Smithsonian Center for Astrophysics and the University of Antioquia (Medellin-Colombia), have devised a novel method for identifying rings around extrasolar planets (exorings).  The method is relatively simple and can be used to rapidly analyze large photometric database and to find a list of exoring candidates deserving further analysis.
Exoplanetary science is one of the most prolific sources of astronomical discoveries since the invention of telescopes.  Once you get used to a suprising finding, such as the discovery of an Earth-twin, another exciting discovery beckons, capturing the imagination of scientists and non-scientists.  Although we cannot predict the next exoplanetary discovery, several breakthroughs, such as the discovery of the first exomoon or the direct image of an Earth-like planet, have been in the line for years.  Exorings are also one of these long-awaited discoveries.  
Recently, a group of astronomers lead by Matt Kenworthy of the Leiden Observatory and Erik Mamajek of the Rochester University, announced the discovery of a huge disk orbiting the "Super-Jupiter" J1407b.  Beside the initial excitement, the actual nature of the object and its "rings" is still debated.  The planet could actually be a brown-dwarf and the rings a version in miniature of a protoplanetary disk.
Rings are common in the Solar System.  Jupiter, Saturn, Uranus and Neptune have rings of different sizes.  Even smaller objects, such as asteroids and cometary nuclei, could have their own rings.  Searching for ringed planets beyond the Solar System is as natural as searching for moons and magnetic fields, two other common phenomena associated with planets.
Jorge I. Zuluaga, Associate Professor in the Institute of Physics of the University of Antioquia and Visitor Scholar of the Harvard-Smithsonian Center for Astrophysics (CfA), David Kipping, Menzel Fellow in the CfA and leading expert in exoplanetary research, and two of their undergraduate and undergraduate students, Mario Sucerquia and Jaime Andrés Alvarado, have discovered a fast and novel method for identifying exorings in large photometric databases.  The method could pave the way for the discovery of the first exorings in the very near future.  Their ideas has been accepted for publication in a forecoming issue of Astrophysical Journal Letters.  An eprint version of the paper is already available in the arXiv repository.
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Schematic representation of the transit of a ringed planet in front of its star.  When compared with the light curve of an non-ringed analogue (dashed line) the transit of a ringed planet is deeper (the relative flux diminish by a larger fraction) and longer.
One of the most exciting aspect of the new method is its simplicity: a ringed-planet will produce a "deeper" and longer transit than that produced by a non-ringed twin (see figure).
But, how can a "deeper" and longer transit of a ringed planet be distinguished from the same effect caused by a larger one?.  If a Jupiter-sized planet have a ring, Astronomers on Earth, studying the transit of the planet in front of its host star, will think the object is much larger than it actually is.   Finding planet much larger than jupiter is not common.  Only brown dwarf and small stars are that big.  In photometric survey, such as that of the Kepler Space Telescope, objects that appear bigger than expected, are normally tagged as "false positives".  According to Zuluaga and Kipping, we should start looking carefully on these false positives.  True "ringed jewels" could be hidden among this apparent "trash".
A second idea exploits the so-called "Asterodensity-profiling effect".   Planetary transits have a wealth of information, not only about the planet, but about the star itself.  If we combine the transit depth (that depends on the size of the star) and the duration of the transit (that depends on orbital velocity and hence on the stellar mass) we can estimate the density of the star.  This transit-based stellar density could be then compared with the density measured independently with another method (asteroseismology for example).  If they do not coincide, something is really wrong with our assumptions about the planet or its orbit.  Zuluaga, Kipping et al. have demonstrated that the presence of Rings leads to a systematic underestimation of stellar density.  This effect is called the "Photo-ring effect".
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Magnitude of the so-called Photo-ring effect predicted by Zuluaga, Kipping et al., at different projected inclinations and tilts (small "saturns").
The identification of rings with this novel method is not enough to claim the discovery and confirmation of an exoring.  Once a list of suitable candidates be selected, a battery of powerful and efficient methods must be used to actually confirm the existence of exorings around some of those candidates.  Even in that case, the new method has the potential to provide the statistical distribution of exorings properties, well before we discover a significant number of them.
Credit of the images:
Saturn Eclipsing the Sun as seen from Cassini Spacecraft.  NASA/JPL.
Original source:
"A novel method for identifying exoplanetary ring", Jorge I. Zuluaga (Harvard-Smithsonian CfA/IF/UdeA), David Kipping (Harvard-Smithsonian CfA), Mario Sucerquia (IF/UdeA), Jaime A. Alvarado (IF/UdeA), arXiv e-print: 1502.07818.  Accepted for Publication in Astrophysical Journal Letters.
Quelle: Institute of Physics, University of Antioquia (Medellin-Colombia)

Tags: Astronomie 

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Sonntag, 8. März 2015 - 10:43 Uhr

Raumfahrt - Neueste MESSENGER Datenübertragung enthält neue zielgerichtete Mosaiken von Merkur

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NASA's Planetary Data System (PDS) today released data collected from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) mission during its 37th through 42nd months in orbit about Mercury.
NASA requires that all of its planetary missions archive their data in the PDS, which makes available documented, peer-reviewed data to the research community. This 13th delivery from the MESSENGER team includes formatted raw and calibrated data collected through 17 September 2014 by the spacecraft's seven science instruments and the Radio Science investigation. Spacecraft, planet, instrument, camera-matrix, and events (SPICE) metadata from launch through the period of this release are also available. 
The delivery includes new advanced products created from data acquired through March 17, 2014, encompassing the first six full Mercury solar days of MESSENGER orbital operations. Now available are global high-incidence east- and west-illumination maps and high-resolution regional targeted mosaics acquired by the Mercury Dual Imaging System (MDIS),
"Images for the global high-incidence maps were acquired when the Sun was very low on the horizon, which accentuates our view of surface topography because even small geologic features catch the Sun and cast long shadows," explained Brett Denevi, a planetary geologist at the Johns Hopkins University Applied Physics Laboratory (APL), in Laurel, Md., and the Deputy Instrument Scientist for MDIS. "MDIS took images just after dawn and just before dusk, because asymmetrical features, such as thrust faults, are likely more visible in one illumination direction than the other. Moreover, crater walls and features that appear in shadow in one map will be illuminated in the other."
Creating the global maps, as with the high-incidence mosaics, requires a compromise, she explained. "In order to obtain coverage as close to global as possible, we have to sacrifice image resolution in many areas. These global maps are complemented by the regional targeted mosaics, which provide high-resolution images of selected sites of high scientific interest."
"The targets were chosen by the science team as areas for further investigation, and they have provided some of our most spectacular views of small-scale features such as hollows, fresh impact craters, and volcanic vents," she said. "In some cases these views are monochrome images acquired with the narrow-angle camera, and in others we opted for images acquired using the color filters of the slightly lower-resolution wide-angle camera."
This PDS also includes viewing normalizations, flux maps, and two-dimensional pitch-angle products from the Fast Imaging Plasma Spectrometer (FIPS) on the Energetic Particle and Plasma Spectrometer (EPPS) instrument.
"The new FIPS PDS data products simultaneously provide users with the most often used two-dimensional and three-dimensional data products, as well as the tools needed to create their own," explained Jim Raines, a space plasma physicist at the University of Michigan and FIPS Instrument Scientist. "The new angular flux maps provide the best visualization of the direction that plasma ions are traveling in Mercury's space environment, which is a key quantity for understanding the behavior of the system. The new energy-resolved pitch-angle distributions give this information relative to the local magnetic field, which can be useful for identifying ions that are expected to impact Mercury's surface and cause space weathering." 
"The viewing normalizations product contains the time-dependent rotation matrices needed for users to form their own versions of these and other multi-dimensional products, with arbitrary time accumulations," he added.
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Of Interest: This mosaic of Caloris basin is an enhanced-color composite overlain on a monochrome mosaic featured in a previous post. The color mosaic is made up of WAC images obtained when both the spacecraft and the Sun were overhead, conditions best for discerning variations in albedo, or brightness. The monochrome mosaic is made up of WAC and NAC images obtained at off-vertical Sun angles (i.e., high incidence angles) and with visible shadows so as to reveal clearly the topographic form of geologic features. The combination of the two datasets allows the correlation of geologic features with their color properties. In portions of the scene, color differences from image to image are apparent. Ongoing calibration efforts by the MESSENGER team strive to minimize these differences.
Caloris basin has been flooded by lavas that appear orange in this mosaic. Post-flooding craters have excavated material from beneath the surface. The larger of these craters have exposed low-reflectance material (blue in this mosaic) from beneath the surface lavas, likely giving a glimpse of the original basin floor material. Analysis of these craters yields an estimate of the thickness of the volcanic layer: 2.5–3.5 km (1.6–2.2 mi.).
The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unraveling the history and evolution of the Solar System's innermost planet. In the mission's more than three years of orbital operations, MESSENGER has acquired over 250,000 images and extensive other data sets. MESSENGER is capable of continuing orbital operations until early 2015.
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Of Interest: The volcanic vent northeast of Rachmaninoff basin is framed perfectly in this image. The surface in some regions appears smooth, having been blanketed by very fine particles ejected explosively from the vent. Other regions, like those in the right hand side of the depression, exhibit more texture indicating a younger age. The textured walls indicate downslope movement of material, and a bright horizontal layer just beneath the surface can be traced along much of the northeastern wall. 
This image was acquired as a high-resolution targeted color observation. Targeted color observations are images of a small area on Mercury's surface at resolutions higher than the 1-kilometer/pixel 8-color base map. During MESSENGER's one-year primary mission, hundreds of targeted color observations were obtained. During MESSENGER's extended mission, high-resolution targeted color observations are more rare, as the 3-color base map covered Mercury's northern hemisphere with the highest-resolution color images that are possible.
The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unraveling the history and evolution of the Solar System's innermost planet. In the mission's more than three years of orbital operations, MESSENGER has acquired over 250,000 images and extensive other data sets. MESSENGER is capable of continuing orbital operations until early 2015.
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Of Interest: Mercury's surface is riven by large tectonic structures that formed when the planet's interior cooled and contracted. One of the most notable such structures is Enterprise Rupes, a lobate scarp system 822 km (510 mi.) in length. Enterprise Rupes cross-cuts the majestic Rembrandt impact basin, some 716 km (445 mi.) across. Rembrandt itself hosts numerous examples where lobate scarps cross smaller craters, such as that shown here. The scarp in this scene lies close to the perimeter of Rembrandt and parallels the basin's outline, before crossing Enterprise Rupes itself farther to the north.
This image was acquired as a high-resolution targeted observation. Targeted observations are images of a small area on Mercury's surface at resolutions much higher than the 200-meter/pixel morphology base map. It is not possible to cover all of Mercury's surface at this high resolution, but typically several areas of high scientific interest are imaged in this mode each week.
The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unraveling the history and evolution of the Solar System's innermost planet. In the mission's more than three years of orbital operations, MESSENGER has acquired over 250,000 images and extensive other data sets. MESSENGER is capable of continuing orbital operations until early 2015.
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Of Interest: Remember this? Since its first observation in 2009, the volcanic vent complex to the northeast of Rachmaninoff basin has rewarded us with remarkable views of its explosive history. Portions of the vent are blanketed in a layer of very fine-grained material thought to be composed of pyroclastic particles, and when we last saw this landform at very high resolution we could appreciate just how fine that texture is. Now, with a resolution almost four times greater than that last image, we can see how the pyroclastic deposit softens the form of adjacent impact craters—almost like snow.
Fiery, hot, angry snow.
This image was acquired as a high-resolution targeted observation. Targeted observations are images of a small area on Mercury's surface at resolutions much higher than the 200-meter/pixel morphology base map. It is not possible to cover all of Mercury's surface at this high resolution, but typically several areas of high scientific interest are imaged in this mode each week.
The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unraveling the history and evolution of the Solar System's innermost planet. In the mission's more than three years of orbital operations, MESSENGER has acquired over 250,000 images and extensive other data sets. MESSENGER is capable of continuing orbital operations until early 2015.
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Of Interest: Impact crater floors are commonly flat and relatively smooth, the result of the cooling and solidification of impact melt generated by the impact event itself. Often, the pool of impact melt cracks as it cools, a process well illustrated by the striking Abedin crater. Although not visible in the frame above, this crater also hosts cooling cracks on its floor. It also boasts numerous terraces along its inner wall, which likely formed after the impact melt solidified. Note how the fine-grained texture of the inner walls contrasts with the crater's floor.
This image was acquired as a high-resolution targeted observation. Targeted observations are images of a small area on Mercury's surface at resolutions much higher than the 200-meter/pixel morphology base map. It is not possible to cover all of Mercury's surface at this high resolution, but typically several areas of high scientific interest are imaged in this mode each week.
The MESSENGER spacecraft is the first ever to orbit the planet Mercury, and the spacecraft's seven scientific instruments and radio science investigation are unraveling the history and evolution of the Solar System's innermost planet. In the mission's more than three years of orbital operations, MESSENGER has acquired over 250,000 images and extensive other data sets. MESSENGER is capable of continuing orbital operations until early 2015.
Quelle: NASA

Tags: Raumfahrt 

1884 Views

Samstag, 7. März 2015 - 11:52 Uhr

Raumfahrt - Atmosphärenforschung mit Raketen: WADIS-2 untersucht Schwerewellen

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Die Atmosphäre ist ein hochkomplexes System, in dem Effekte wie Sonneneinstrahlung, wechselnde Gaszusammensetzungen, Staub, Eiskristalle und elektrische Aufladung zusammenspielen. Sie beeinflussen sowohl das Wettergeschehen als auch die Klimaentwicklung. Speziell die Dichteänderungen in der Mittleren Atmosphäre untersucht das WADIS-Projekt (Wellenausbreitung und Dissipation in der Mittleren Atmosphäre) des Leibniz-Instituts für Atmosphärenphysik (IAP) in Kühlungsborn mit Unterstützung des Deutschen Zentrums für Luft- und Raumfahrt (DLR). Am 5. März 2015 um 2:44 Uhr Mitteleuropäischer Zeit startete die Höhenforschungsrakete WADIS-2 vom Andøya Space Center mit neun Experimenten an Bord in den Nachthimmel über Norwegen. Zusätzlich wurden 13 kleine, einfache "Wetterraketen" vom Typ Loki-Dart gestartet, die Druck und Temperatur in den Tagen vor und nach dem WADIS-Start messen, um damit ein größeres Wetterumfeld bestimmen zu können.
Die insgesamt 1550 Kilogramm schwere WADIS-2-Rakete erreichte eine Höhe von rund 126 Kilometern. Die Experiment-Sensoren ermittelten während des Fluges Luftdruck, Temperatur, elektrische Ladungen sowie Dichteänderungen in der Atmosphäre. Diese Änderungen in der Luftdichte, so genannte Schwerewellen, lassen sich in Form von Temperatur-, Druck- und Windschwankungen messen. Sie treten beispielsweise dort auf, wo Windströmungen in Bodennähe auf ein Hindernis, etwa ein Gebirgsmassiv, treffen und diese Störungen sich bis in 80 Kilometer Höhe fortsetzen. Das Phänomen der Schwerewellen ist zwar bekannt, aber in weiten Bereichen noch nicht genau erforscht worden. Dies ist jedoch eine wichtige Voraussetzung, um Klimamodelle künftig zu verbessern.
An Bord von WADIS-2 befanden sich auch fünf deutsche Experimente. Drei davon stammten von Wissenschaftlern des Leibniz-Instituts für Atmosphärenphysik: die CONE-Sensoren (Combined Measurement of Neutrals and Electrons) zur Messung von Dichteschwankungen, ein Partikelsensor zur Ermittlung von Aerosolen und eine so genannte fallende Kugel (Active Falling Sphere). Fallende Kugeln wurden schon früher in der Meteorologie eingesetzt. Man ließ sie in einer gewissen Höhe fallen und konnte über Radar-Messungen vom Boden aus die Luftdichte, Temperatur und horizontale Windgeschwindigkeiten bestimmen. Diese 25 Zentimeter große und drei Kilogramm schwere fallende Kugel hat eigene Messgeräte an Bord, weshalb sie als "aktiv" bezeichnet wird. Dies sind 3D-Beschleunigungssensoren, Kreisel, GPS-Empfänger und eine Funkelektronik. Die Kugel befand sich zwischen dem Raketenmotor und der Nutzlast und wurde nach der Abtrennung des Motors ausgeworfen.
Nach etwa zehn Minuten Flugzeit wasserte die Nutzlasteinheit im Nordatlantik rund 80 Kilometer vor der norwegischen Küste. Dort wurde sie von einem Bergungsschiff an Bord genommen und zur weiteren Auswertung der Experimente zurück nach Andoya transportiert. Bereits eineinhalb Jahre zuvor, am 28. Juni 2013, war die Vorgängerrakete, WADIS-1 gestartet. Während diese Mission in der Übergangszeit zwischen Frühling auf Sommer erfolgte, wurde WADIS-2 im Winter gestartet. Aus wissenschaftlicher Sicht ist dieser Unterschied sehr wichtig, da die Atmosphäre sich dann in unterschiedlichen Zuständen befindet. Aus diesen Unterschieden kann die Wissenschaft dann sehr gut auf die dort ablaufenden Prozesse schließen. Mit dem WADIS-Projekt wird die Forschung des ECOMA-Programms fortgeführt, bei dem von September 2006 bis Dezember 2010 neun Höhenforschungsraketen gestartet wurden.
Das WADIS-Projekt steht unter wissenschaftlicher Leitung des Leibniz-Instituts für Atmosphärenphysik. Weitere Partner sind die Universität Stuttgart und die Ludwig-Maximilians Universität in München. Die Instrumente wurden zum Teil von der Schwetzinger Firma Von Hoerner & Sulger Gmbh gefertigt, die "Active Falling Sphere" wurde vom IAP, der Firma Argus Electronik GmbH und dem Institut für Allgemeine Elektrotechnik der Universität Rostock entwickelt. Für die Durchführung der Startkampagne war die Mobile Raketenbasis des Deutschen Zentrums für Luft- und Raumfahrt (DLR-MORABA) in Oberpfaffenhofen zuständig. Unterstützt wird das Projekt vom DLR Raumfahrtmanagement mit Mitteln des Bundesministeriums für Wirtschaft und Energie (BMWi).
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Quelle: DLR

Tags: Raumfahrt 

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Samstag, 7. März 2015 - 11:21 Uhr

Raumfahrt - Mars Webcam: Haben Sie schon einmal eine Kamera an Bord eines interplanetaren Raumfahrzeug benutzt?

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New views from the Mars Webcam 4 March 2013
Some recent views of the Red Planet from the Visual Monitoring Camera, the "Mars Webcam" on board the Mars Express orbiter. Left: the great Valles Marineris canyon can be seen near the upper right side of the disc, filled with mist or dust. Center: a clear view of the canyon, and all the way down to the south polar cap. Right: weather on the horizon. Some recent views of the Red Planet from the Visual Monitoring Camera, the "Mars Webcam" on board the Mars Express orbiter. Left: the great Valles Marineris canyon can be seen near the upper right side of the disc, filled with mist or dust. Center: a clear view of the canyon, and all the way down to the south polar cap. Right: weather on the horizon. 
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In May, the ‘webcam’ on board Mars Express will be available for public imaging requests. We’re inviting schools, science clubs and youth groups to submit proposals for one of eight opportunities to image another planet.
ESA are inviting public proposals for a number of observation slots using the Visual Monitoring Camera (VMC) on board Mars Express.
VMC – the 'Mars Webcam' – is a simple, low-resolution device that was originally intended only to provide visual confirmation of Beagle lander separation. Since 2007, it has provided unique images of Mars, including crescent views of the planet not obtainable from Earth, which are routinely shared via a dedicated blog and Flickr.
While it's not a scientific instrument as such, and despite the low resolution, the camera delivers good quality pictures of intriguing martian features, including cloud and atmospheric activity and surface features like Olympus Mons and the Tharsis Montes.
In May, Mars will be in solar conjunction, meaning that line-of-sight radio signals between Earth and Mars Express will be disrupted by the Sun. As a result, the spacecraft's professional scientific payload will be switched off. This offers a first-ever, three-day period when the VMC camera can be freely pointed at almost any target from almost any point in the 300 x 10 000 km orbit.
VMC Imaging Campaign – call for proposals
We're inviting schools, astronomy clubs, science centres and other youth-engaged organisations (see eligibility details here) to propose targets for VMC imaging, which will be scheduled into an observation campaign that will run from 25–27 May.
While any number of eligible groups may submit proposals, only the most promising will be selected, one slot per group, corresponding to the eight (or so) observation slots available (the number varies depending on the targets proposed).
Proposals must include the desired observation target, a brief note about why it's interesting and a description of the intended project that will fully exploit the images. Proposals with strong educational value and representing a cohesive team effort will have the best chances of being accepted.
In return, ESA expects that groups that are awarded a slot will use 'their' image set in a scientific or artistic project that makes full, imaginative use of the visual information they contain. The projects must be shared with us, and we'll publish these later in the VMC blog.
The VMC image sets will be downloaded to Earth by 28 May, and then delivered to participating groups electronically. Projects should be completed by the end of the current academic year, or 31 July, whichever comes first.
In principle, almost any large feature on the martian surface can be imaged. However, during the limited three-day imaging campaign, the Mars Express orbits may not offer the best views of all possible targets.
A more-detailed description of the Mars Express orbits, ranges of visibilities and timings/altitudes for imaging slots, together with examples of potential targets – like Meridiani Planum, the target location for ESA's 2016 Mars lander, Schiaparelli – are available in the Mars Express blog.
Timeline to registration
The call for proposals period opens today and runs through to 27 March; any interested groups must register via the link below to indicate their interest and provide details on their requested imaging target and their planned science/art project.
On 19 March, the Mars Express mission team will provide a tutorial via an #ESAHangout in Google+ and YouTube on the VMC camera and how its images are planned and acquired. Proposals can be amended afterwards, and all submissions must be firm by 27 March.
We'll announce the successful proposals a few days later.
Online registration
Full details on the VMC Imaging Campaign timeline, eligibility, registration and technical information are available via this link:
Online registration: Deadline 12:00 CET, 27 March
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On 4 June 2014, the VMC 'Mars Webcam' captured this view of the northern polar cap and what seems to be further dust/cloud formations around the pole; the image also shows some of the biggest geological features on the planet. Credit: ESA/Mars Express/VMC
Quelle: ESA

Tags: Raumfahrt 

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Freitag, 6. März 2015 - 23:00 Uhr

Raumfahrt - Mars-Chroniken - Curiosity Mars-Rover nach Elektrischen Störung lahm gelegt - Update

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5.03.2015

The Mars Curiosity rover was in the processing of transferring a sample of powder it had drilled out of a rock when an electrical short triggered an automated shutdown.
NASA/JPL-CALTECH
Engineers at NASA’s Jet Propulsion Laboratory are scrambling to figure out the cause of an electrical glitch on the Mars rover Curiosity which stopped science operations cold.
The rover had finished drilling a sample from a rock known as “Telegraph Peak” and was transferring the powder into laboratory instruments when an abnormal electrical current was detected, NASA said in a statement posted on its website on Tuesday.
“We are running tests on the vehicle in its present configuration before we move the arm or drive,” Curiosity project manager Jim Erickson said in the statement. “This gives us the best opportunity to determine where the short is.”
NASA said that the short could have little impact on rover operations, or it could be more significant.  Analysis to determine the cause of the problem and assess what, if any, changes need to be made is expected to take several days.
Curiosity was in the early stages of transferring the powdered rock from a drill located on the rover’s arm to instruments for analysis.
“With the drill bit pointed up and the the drill’s percussion mechanism turned on, the rock powder was descending from collection grooves in the bit assembly into a chamber in the mechanism the sieves and portions the sample powder,” when the electrical short occurred,” NASA said.
The rover, which had performed the same transfer operation five times previously, automatically put itself into a safe mode.
Curiosity is exploring the base of a three-mile-high mountain of layered sediment inside its Gale Crater landing site. It already has returned evidence that Mars, the planet most like Earth in the solar system, had all the ingredients necessary for microbial life. It is assessing other niches for environmental and chemical habitability, as well as looking for places suitable to preserve organic matter.
Quelle: D-News
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Mars Science Laboratory Mission Status Report
NASA's Curiosity Mars rover is expected to remain stationary for several days of engineering analysis following an onboard fault-protection action on Feb. 27 that halted a process of transferring sample material between devices on the rover's robotic arm.
Telemetry received from the rover indicated that a transient short circuit occurred and the vehicle followed its programmed response, stopping the arm activity underway at the time of the irregularity in the electric current.
"We are running tests on the vehicle in its present configuration before we move the arm or drive," said Curiosity Project Manager Jim Erickson, of NASA's Jet Propulsion Laboratory in Pasadena, California. "This gives us the best opportunity to determine where the short is."
A transient short in some systems on the rover would have little effect on rover operations. In others, it could prompt the rover team to restrict use of a mechanism.
When the fault occurred, the rover was conducting an early step in the transfer of rock powder collected by the drill on the arm to laboratory instruments inside the rover. With the drill bit pointed up and the drill's percussion mechanism turned on, the rock powder was descending from collection grooves in the bit assembly into a chamber in the mechanism that sieves and portions the sample powder. The sample powder is from a rock target called "Telegraph Peak."  The same transfer process was completed smoothly with samples from five previous drilling targets in 2013 and 2014.
NASA's Mars Science Laboratory Project is using Curiosity to assess ancient habitable environments and major changes in Martian environmental conditions.  JPL, a division of the California Institute of Technology in Pasadena, built the rover and manages the project for NASA's Science Mission Directorate in Washington.
Quelle: NASA
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Update: 6.03.2015
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Use of Rover Arm Expected to Resume in a Few Days
This March 4, 2015, image from the Navcam on NASA's Curiosity Mars rover shows the position in which the rover held its arm for several days after a transient short circuit triggered onboard fault-protection programming to halt arm activities on Feb. 27.
Image Credit: NASA/JPL-Caltech/MSSS
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Mission Status Report
Managers of NASA's Curiosity Mars rover mission expect to approve resumption of rover arm movements as early as next week while continuing analysis of what appears to be an intermittent short circuit in the drill.
A fluctuation in current on Feb. 27 triggered a fault-protection response that immediately halted action by the rover during the mission's 911th Martian day, or sol. Since then, the rover team has avoided driving Curiosity or moving the rover's arm, while engineers have focused on diagnostic tests. Science observations with instruments on the rover's mast have continued, along with environmental monitoring by its weather station.
"Diagnostic testing this week has been productive in narrowing the possible sources of the transient short circuit," said Curiosity Project Manager Jim Erickson of NASA's Jet Propulsion Laboratory, Pasadena, California. "The most likely cause is an intermittent short in the percussion mechanism of the drill. After further analysis to confirm that diagnosis, we will be analyzing how to adjust for that in future drilling."
The sample-collection drill on Curiosity's robotic arm uses both rotation and hammering, or percussion, to penetrate into Martian rocks and collect pulverized rock material for delivery to analytical instruments inside the rover.
The short on Sol 911 occurred while the rover was transferring rock-powder sample from the grooves of the drill into a mechanism that sieves and portions the powder. The percussion action was in use, to shake the powder loose from the drill.
Engineers received results Thursday, March 5, from a test on Curiosity that similarly used the drill's percussion action. During the third out of 180 up-and-down repeats of the action, an apparent short circuit occurred for less than one one-hundredth of a second.  Though small and fleeting, it would have been enough to trigger the fault protection that was active on Sol 911 under the parameters that were in place then.
The rover team plans further testing to characterize the intermittent short before the arm is moved from its present position, in case the short does not appear when the orientation is different.
After those tests, the team expects to finish processing the sample powder that the arm currently holds and then to deliver portions of the sample to onboard laboratory instruments. Next, Curiosity will resume climbing Mount Sharp.
NASA's Mars Science Laboratory Project is using Curiosity to assess ancient habitable environments and major changes in Martian environmental conditions.  JPL, a division of the California Institute of Technology in Pasadena, built the rover and manages the project for NASA's Science Mission Directorate in Washington.  For more information about Curiosity,
Quelle: NASA

Tags: Raumfahrt 

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Freitag, 6. März 2015 - 09:25 Uhr

Raumfahrt - Mars-Chroniken: Mars Rover Opportunity News

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This map updates progress that NASA's Mars Exploration Rover Opportunity is making toward reaching a driving distance equivalent to a marathon footrace. Image Credit: NASA/JPL-Caltech/Univ. of Arizona

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NASA's Mars Exploration Rover Opportunity climbed last month to an overlook for surveying "Marathon Valley," a science destination chosen because spectrometer observations from orbit indicate exposures of clay minerals.
Near the overlook, it found blocky rocks so unlike any previously examined on Mars that the rover team has delayed other activities to provide time for a thorough investigation.
"We drove to the edge of a plateau to look down in the valley, and we found these big, dark-gray blocks along the ridgeline," said Opportunity Project Scientist Matt Golombek of NASA's Jet Propulsion Laboratory, Pasadena, California. "We checked one and found its composition is different from any ever measured before on Mars. So, whoa! Let's study these more before moving on."
The first rock checked at the site has relatively high concentrations of aluminum and silicon, and an overall composition not observed before by either Opportunity or its twin rover, Spirit. This was determined by examining the rock, called "Jean-Baptiste Charbonneau," with the Alpha Particle X-ray Spectrometer instrument on the end of Opportunity's robotic arm. The next target rock at the site is called "Sergeant Charles Floyd." The team's target-naming theme in the area is from the Lewis and Clark expedition.
Although the rocks are gray, the visible-light spectrum of the Charbonneau type has more purple than most Mars rocks, and the spectrum of the Floyd type has more blue. Of the two types, the bluer rocks tend to lie higher on the ridge.
Actions to restore use of Opportunity's non-volatile flash file system will resume after inspection of the rocks on this ridge. Due to recurrent problems with the flash memory, including "amnesia events" and computer resets, Opportunity has been operating since late 2014 in a mode that avoids use of the flash memory.
Between the stops at Charbonneau and Floyd, the rover team uploaded to Opportunity a new version of the rover's flight software. The new version is designed to use only six of the rover's seven banks of flash memory. It will avoid the seventh bank, known to be a problem area.
The rover is using the new software, but a memory reformatting will be needed before resuming use of flash memory. After reformatting, the operations team will avoid use of the rover's arm for several days to make sure the flash file system is fixed and no longer causes resets. A reset during the use of the rover's arm would require a complex recovery effort.
As of March 5, Opportunity has driven 26.139 miles (42.067 kilometers) since it landed on Mars in January 2004. This brings it within 140 yards (128 meters) of reaching the distance of a marathon footrace.
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The flat-faced rock near the center of this image is a target for contact investigation by NASA's Mars Exploration Rover Opportunity in early March 2015.
The view is from the rover's front hazard avoidance camera on March 3, 2015, during the 3,948th Martian day, or sol, of Opportunity's work on Mars. This camera is mounted low on the rover and has a wide-angle lens. The scene includes a shadow of the tool turret at the end of Opportunity's robotic arm.
The rock includes a target called "Sergeant Charles Floyd," for the quartermaster of the Lewis and Clark expedition.
Quelle: NASA

Tags: Raumfahrt 

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