Time lapse photo mosaic was assembled from Phoenix images taken of the lander deck and martian terrain. Panorama shows the robotic arm in action as it scoops up soil samples (right) and delivers the samples to the MECA and TEGA science instruments (left). Credit: Marco Di Lorenzo, Kenneth Kremer - NASA/JPL/UA/Spaceflight
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As expected, NASA’s February 2010 listening campaign for the Phoenix Mars Lander has failed to detect any signals emanating from the long silent vehicle. NASA’s attempts to reestablish contact with Phoenix were restarted in January 2010 and timed to coincide with the onset of springtime and disappearance of ice at her location in the martian north polar regions. In theory, the return of abundant sunshine striking the twin energy producing solar arrays could again power up the science lander sufficiently to revive itself and ‘phone home’ to Earth.
This just completed 2nd listening campaign consisted of 60 overflights conducted by NASA’s Mars Odyssey orbiter from Feb 22 to Feb 26. The first campaign was conducted in January and likewise yielded no signals of activity. But with each passing Sol, or martian day, the sun is now rising higher in the sky and impinging longer on the solar powered craft. A third campaign is scheduled for early April 2010 just in case the sun enables a miraculous revival. The sun will be continuously above the Martian horizon in April.
Check out the time lapse photo mosaic above, created by Marco Di Lorenzo and Ken Kremer, which shows Phoenix actively at work as she digs up Martian icy soil samples and delivers them to the MECA and TEGA science instruments on the lander deck for compositional analysis.
It’s currently mid-springtime at the landing site with about 22 hours of sunlight each Sol. That illumination is comparable to the period when Phoenix was in full swing in the middle of her mission.
“Each overflight lasts about 10 minutes”, says Doug McCuistion, the director of Mars Exploration at NASA Headquarters in Washington, DC. But no one at NASA or on the science and engineering teams is under any illusions. “We think the chances are very low that Phoenix survived winter”, McCuistion told me in an interview.
NASA is using both of its Martian orbiting assets currently circling above the red planet to ascertain the condition of Phoenix. “Odyssey is the prime communications spacecraft. The Mars Reconnaissance Orbiter (MRO) will try to image Phoenix about every 2 weeks”, McCuistion said to me. See the latest MRO images herein which show a receding ice layer.
Stages in the seasonal disappearance of surface ice from the ground around the Phoenix Mars Lander are visible in these images taken on Feb. 8, 2010, (left) and Feb. 25, 2010 by the HiRise Camera on NASA’s Mars Reconnaissance Orbiter, during springtime on northern Mars. The views cover an area about 100 meters wide. North is toward the bottom. Credit: NASA/JPL-Caltech/University of Arizona
Phoenix was pre-programmed with a Lazarus mode to reawaken itself in the unlikely event that it survived the exceedingly harsh northern Martian winter during which it endured extremely low temperatures for longer than 1 earth year already. Furthermore, the spacecraft was potentially even partially encased in up to several feet of ice during several months of continuous arctic darkness. Unlike the rovers Spirit and Opportunity, Phoenix was not designed to withstand Martian winter.
After more than 5 months of intensive and breakthrough science investigations, all contact with Phoenix was lost on 2 November 2008 as increasing storm clouds blocked the waning sun from reaching the life giving solar arrays and the vehicle could no longer function.
Phoenix lasted more than 2 months beyond her planned primary mission design of 3 months. She discovered that Mars currently possesses a habitable environment with water and nutrients that could sustain potential past or current martian life forms, IF they exist. Read my earlier Phoenix report to learn about the robust science program that could be carried out to build on the initial results, if this bird rises again.
Artist impression of LCROSS approaching the Moon. Credit: NASA
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Almost five months ago, the LCROSS spacecraft had an abrupt end to its flight when it impacted a crater on the Moon’s south pole. But that was only the beginning of the work of principal investigator Tony Colaprete and the rest of the science teams, who have since been working non-stop to get their initial results out to the public. Look for a flood of ‘water on the Moon’ news to be announced at the Lunar and Planetary Science Conference this week.
“The data set from LCROSS is a lot more interesting that we thought it would be,” said Colaprete, speaking on a “My Moon” webcast, sponsored by the Lunar and Planetary Institute. “A big part of our time has been making sure the data is properly calibrated. That takes a lot of time and effort, but the other side of the equation is understanding all the stuff you don’t understand in the data, and there was a lot we didn’t initially understand.”
The LCROSS team will present six papers, 11 posters and several oral sessions at the LPSC.
While the results are still under embargo, Colaprete was able to discuss the basics of what the science teams have found. LCROSS impact site. Credit: NASA
One surprise for the teams was the low “flash” produced by the impact of the spacecraft. “We didn’t see a visible flash, even with sensitive instruments,” Colaprete said. “There was a delayed and muted flash and the impactor was essentially buried, with all the energy apparently deposited at a depth. So it is very likely that there were volatiles in the vicinity.”
The second surprise was the morphology of the impact plume. “We had reason to believe there would be high angle plume,” said Colaprete. “But we had a lower angle plume. We had a signal of a debris curtain in the spectrometers in LCROSS all the way down in the four minutes following the impact of the Centaur stage. That was corroborated with DIVINER measurements with LRO (a radiometer on the Lunar Reconnaissance Orbiter.) They were able to make some great observations of the ejecta cloud with DIVINER, and we had good signals with our instruments all the way down to impact.”
Most surprising, Colaprete said, was all the “stuff” that came up from the impact. “Everyone was really excited and surprised about all the stuff that we threw up with the impact.”
The LRO spacecraft was able to be tilted in orbit so the LAMP (Lyman-Alpha Mapping Project) instrument could observe impact plume. It observed a plume about 20 km tall, and observed a “footprint” of a plume up to 40 km above the Moon’s surface.
“They saw vapor cloud fill the ‘slit’ of the spectrometer’s observations at about 23 seconds after impact and it remained there through the entire flyby,” Colaprete said. “What that corresponds to is a hot vapor cloud of about 1000 degrees that was observed.” A closer view of the moon as the LCROSS spacecraft approaches impact. Credit: NASA
Two exciting species found in the cloud were molecular hydrogen and mercury. “What is fantastic about that, is that there was an article written a couple of decades ago, regarding the possibility of mercury and water at the poles, and they said don’t drink the water!”
Colaprete said observing molecular hydrogen is spectacular because normally it doesn’t stay stable even at 40 Kelvin. The teams are still speculating how it was trapped and what form it was in. They found about 150 kg of molecular hydrogen in the plume.
All the elements found in the plume must be coming from cometary and asteroidal sources, Colaprete said. They also found water ice, sulfur dioxide, methane, ammonia, methanol, carbon dioxide, sodium and potassium. “We haven’t identified everything yet, but what we’re seeing is similar to what you would see in an impact of a comet, like what happened with the Deep Impact probe, which is exciting and surprising. The mineralogy in the dust itself that we kicked up corresponds to what was seen by M Cubed instrument, and also what we see in chondrite asteroids.”
One of the most pleasing aspects of this scientific process, Colaprete said, was the different teams being able to verify what other teams were finding.
“The concentration of hydrogen we saw in the regolith was higher than expected,” Colaprete said. “We ran the numbers again, and we said, ‘Oh, we can’t wiggle out of this answer.’ Then the PI for the LEND (Lunar Exploration Neutron Detector on LRO, which can acquire high-resolution neutron datasets) instrument confirmed that their numbers were entirely consistent with what we got. It was surprising because it wasn’t what we expected. But that is why you make measurements.”
“This should be a fun year as we pull this all together, and get it released to the public so we can get a lot more neurons looking at this,” Colaprete said. “I think this will really change our understanding of the Moon and how we think about it.”
Thales Alenia Space and EADS Astrium concepts for Euclid (ESA)
Key questions relevant to fundamental physics and cosmology, namely the nature of the mysterious dark energy and dark matter (Euclid); the frequency of exoplanets around other stars, including Earth-analogs (PLATO); take the closest look at our Sun yet possible, approaching to just 62 solar radii (Solar Orbiter) … but only two! What would be your picks?
These three mission concepts have been chosen by the European Space Agency’s Science Programme Committee (SPC) as candidates for two medium-class missions to be launched no earlier than 2017. They now enter the definition phase, the next step required before the final decision is taken as to which missions are implemented.
These three missions are the finalists from 52 proposals that were either made or carried forward in 2007. They were whittled down to just six mission proposals in 2008 and sent for industrial assessment. Now that the reports from those studies are in, the missions have been pared down again. “It was a very difficult selection process. All the missions contained very strong science cases,” says Lennart Nordh, Swedish National Space Board and chair of the SPC.
And the tough decisions are not yet over. Only two missions out of three of them: Euclid, PLATO and Solar Orbiter, can be selected for the M-class launch slots. All three missions present challenges that will have to be resolved at the definition phase. A specific challenge, of which the SPC was conscious, is the ability of these missions to fit within the available budget. The final decision about which missions to implement will be taken after the definition activities are completed, which is foreseen to be in mid-2011.
[/caption] Euclid is an ESA mission to map the geometry of the dark Universe. The mission would investigate the distance-redshift relationship and the evolution of cosmic structures. It would achieve this by measuring shapes and redshifts of galaxies and clusters of galaxies out to redshifts ~2, or equivalently to a look-back time of 10 billion years. It would therefore cover the entire period over which dark energy played a significant role in accelerating the expansion.
By approaching as close as 62 solar radii, Solar Orbiter would view the solar atmosphere with high spatial resolution and combine this with measurements made in-situ. Over the extended mission periods Solar Orbiter would deliver images and data that would cover the polar regions and the side of the Sun not visible from Earth. Solar Orbiter would coordinate its scientific mission with NASA’s Solar Probe Plus within the joint HELEX program (Heliophysics Explorers) to maximize their combined science return. Thales Alenis Space concept, from assessment phase (ESA) PLATO (PLAnetary Transit and Oscillations of stars) would discover and characterize a large number of close-by exoplanetary systems, with a precision in the determination of mass and radius of 1%.
In addition, the SPC has decided to consider at its next meeting in June, whether to also select a European contribution to the SPICA mission.
SPICA would be an infrared space telescope led by the Japanese Space Agency JAXA. It would provide ‘missing-link’ infrared coverage in the region of the spectrum between that seen by the ESA-NASA Webb telescope and the ground-based ALMA telescope. SPICA would focus on the conditions for planet formation and distant young galaxies.
“These missions continue the European commitment to world-class space science,” says David Southwood, ESA Director of Science and Robotic Exploration, “They demonstrate that ESA’s Cosmic Vision programme is still clearly focused on addressing the most important space science.”
An illustration showing the ESA's Mars Express mission. Credit: ESA/Medialab)
Understanding the present-day Martian climate gives us insights into its past climate, which in turn provides a science-based context for answering questions about the possibility of life on ancient Mars.
Our understanding of Mars’ climate today is neatly packaged as climate models, which in turn provide powerful consistency checks – and sources of inspiration – for the climate models which describe anthropogenic global warming here on Earth.
But how can we work out what the climate on Mars is, today? A new, coordinated observation campaign to measure ozone in the Martian atmosphere gives us, the interested public, our own window into just how painstaking – yet exciting – the scientific grunt work can be.
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The Martian atmosphere has played a key role in shaping the planet’s history and surface. Observations of the key atmospheric components are essential for the development of accurate models of the Martian climate. These in turn are needed to better understand if climate conditions in the past may have supported liquid water, and for optimizing the design of future surface-based assets at Mars.
Ozone is an important tracer of photochemical processes in the atmosphere of Mars. Its abundance, which can be derived from the molecule’s characteristic absorption spectroscopy features in spectra of the atmosphere, is intricately linked to that of other constituents and it is an important indicator of atmospheric chemistry. To test predictions by current models of photochemical processes and general atmospheric circulation patterns, observations of spatial and temporal ozone variations are required.
The Spectroscopy for Investigation of Characteristics of the Atmosphere of Mars (SPICAM) instrument on Mars Express has been measuring ozone abundances in the Martian atmosphere since 2003, gradually building up a global picture as the spacecraft orbits the planet.
These measurements can be complemented by ground-based observations taken at different times and probing different sites on Mars, thereby extending the spatial and temporal coverage of the SPICAM measurements. To quantitatively link the ground-based observations with those by Mars Express, coordinated campaigns are set up to obtain simultaneous measurements.
Infrared heterodyne spectroscopy, such as that provided by the Heterodyne Instrument for Planetary Wind and Composition (HIPWAC), provides the only direct access to ozone on Mars with ground-based telescopes; the very high spectral resolving power (greater than 1 million) allows Martian ozone spectral features to be resolved when they are Doppler shifted away from ozone lines of terrestrial origin.
A coordinated campaign to measure ozone in the atmosphere of Mars, using SPICAM and HIPWAC, has been ongoing since 2006. The most recent element of this campaign was a series of ground-based observations using HIPWAC on the NASA Infrared Telescope Facility (IRTF) on Mauna Kea in Hawai’i. These were obtained between 8 and 11 December 2009 by a team of astronomers led by Kelly Fast from the Planetary Systems Laboratory, at NASA’s Goddard Space Flight Center (GSFC), in the USA. Credit: Kelly Fast About the image: HIPWAC spectrum of Mars’ atmosphere over a location on Martian latitude 40°N; acquired on 11 December 2009 during an observation campaign with the IRTF 3 m telescope in Hawai’i. This unprocessed spectrum displays features of ozone and carbon dioxide from Mars, as well as ozone in the Earth’s atmosphere through which the observation was made. Processing techniques will model and remove the terrestrial contribution from the spectrum and determine the amount of ozone at this northern position on Mars.
The observations had been coordinated in advance with the Mars Express science operations team, to ensure overlap with ozone measurements made in this same period with SPICAM.
The main goal of the December 2009 campaign was to confirm that observations made with SPICAM (which measures the broad ozone absorption spectra feature centered at around 250 nm) and HIPWAC (which detects and measures ozone absorption features at 9.7 μm) retrieve the same total ozone abundances, despite being performed at two different parts of the electromagnetic spectrum and having different sensitivities to the ozone profile. A similar campaign in 2008, had largely validated the consistency of the ozone measurement results obtained with SPICAM and the HIPWAC instrument.
The weather conditions and the seeing were very good at the IRTF site during the December 2009 campaign, which allowed for good quality spectra to be obtained with the HIPWAC instrument.
Kelly and her colleagues gathered ozone measurements for a number of locations on Mars, both in the planet’s northern and southern hemisphere. During this four-day campaign the SPICAM observations were limited to the northern hemisphere. Several HIPWAC measurements were simultaneous with observations by SPICAM allowing a direct comparison. Other HIPWAC measurements were made close in time to SPICAM orbital passes that occurred outside of the ground-based telescope observations and will also be used for comparison.
The team also performed measurements of the ozone abundance over the Syrtis Major region, which will help to constrain photochemical models in this region.
Analysis of the data from this recent campaign is ongoing, with another follow-up campaign of coordinated HIPWAC and SPICAM observations already scheduled for March this year.
Putting the compatibility of the data from these two instruments on a firm base will support combining the ground-based infrared measurements with the SPICAM ultraviolet measurements in testing the photochemical models of the Martian atmosphere. The extended coverage obtained by combining these datasets helps to more accurately test predictions by atmospheric models.
It will also quantitatively link the SPICAM observations to longer-term measurements made with the HIPWAC instrument and its predecessor IRHS (the Infrared Heterodyne Spectrometer) that go back to 1988. This will support the study of the long-term behavior of ozone and associated chemistry in the atmosphere of Mars on a timescale longer than the current missions to Mars.
Infrared portrait of the Small Magellanic Cloud, made by NASA's Spitzer Space Telescope
At the end of the proverbial day, space-based missions like Spitzer produce millions of observations of astronomical objects, phenomena, and events. And those terabytes of data are used to test hypotheses in astrophysics which lead to a deeper understanding of the universe and our home in it, and perhaps some breakthrough whose here-on-the-ground implementation leads to a major, historic improvement in human welfare and planetary ecosystem health.
But such missions also leave more immediate legacies, in terms of the pleasure they bring millions of people, via the beauty of their images (not to mention posters, computer wallpaper and screen savers, and even inspiration for avatars).
Some recent results from one of Spitzer’s programs – SAGE-SMC – are no exception.
The image shows the main body of the Small Magellanic Cloud (SMC), which is comprised of the “bar” on the left and a “wing” extending to the right. The bar contains both old stars (in blue) and young stars lighting up their natal dust (green/red). The wing mainly contains young stars. In addition, the image contains a galactic globular cluster in the lower left (blue cluster of stars) and emission from dust in our own galaxy (green in the upper right and lower right corners).
The data in this image are being used by astronomers to study the lifecycle of dust in the entire galaxy: from the formation in stellar atmospheres, to the reservoir containing the present day interstellar medium, and the dust consumed in forming new stars. The dust being formed in old, evolved stars (blue stars with a red tinge) is measured using mid-infrared wavelengths. The present day interstellar dust is weighed by measuring the intensity and color of emission at longer infrared wavelengths. The rate at which the raw material is being consumed is determined by studying ionized gas regions and the younger stars (yellow/red extended regions). The SMC is one of very few galaxies where this type of study is possible, and the research could not be done without Spitzer.
This image was captured by Spitzer’s infrared array camera and multiband imaging photometer (blue is 3.6-micron light; green is 8.0 microns; and red is combination of 24-, 70- and 160-micron light). The blue color mainly traces old stars. The green color traces emission from organic dust grains (mainly polycyclic aromatic hydrocarbons). The red traces emission from larger, cooler dust grains.
The image was taken as part of the Spitzer Legacy program known as SAGE-SMC: Surveying the Agents of Galaxy Evolution in the Tidally-Stripped, Low Metallicity Small Magellanic Cloud.
The Small Magellanic Cloud (SMC), and its larger sister galaxy, the Large Magellanic Cloud (LMC), are named after the seafaring explorer Ferdinand Magellan, who documented them while circling the globe nearly 500 years ago. From Earth’s southern hemisphere, they can appear as wispy clouds. The SMC is the further of the pair, at 200,000 light-years away.
Recent research has shown that the galaxies may not, as previously suspected, orbit around our galaxy, the Milky Way. Instead, they are thought to be merely sailing by, destined to go their own way. Astronomers say the two galaxies, which are both less evolved than a galaxy like ours, were triggered to create bursts of new stars by gravitational interactions with the Milky Way and with each other. In fact, the LMC may eventually consume its smaller companion.
Karl Gordon, the principal investigator of the latest Spitzer observations at the Space Telescope Science Institute in Baltimore, Maryland, and his team are interested in the SMC not only because it is so close and compact, but also because it is very similar to young galaxies thought to populate the universe billions of years ago. The SMC has only one-fifth the amount of heavier elements, such as carbon, contained in the Milky Way, which means that its stars haven’t been around long enough to pump large amounts of these elements back into their environment. Such elements were necessary for life to form in our solar system.
Studies of the SMC therefore offer a glimpse into the different types of environments in which stars form.
“It’s quite the treasure trove,” said Gordon, “because this galaxy is so close and relatively large, we can study all the various stages and facets of how stars form in one environment.” He continued: “With Spitzer, we are pinpointing how to best calculate the numbers of new stars that are forming right now. Observations in the infrared give us a view into the birthplace of stars, unveiling the dust-enshrouded locations where stars have just formed.” Little Galaxy with a Tail (Small Magellanic Cloud imaged by Spitzer)
This image shows the main body of the SMC, which is comprised of the “bar” and “wing” on the left and the “tail” extending to the right. The tail contains only gas, dust and newly formed stars. Spitzer data has confirmed that the tail region was recently torn off the main body of the galaxy. Two of the tail clusters, which are still embedded in their birth clouds, can be seen as red dots.
The immense Andromeda galaxy, also known as Messier 31 or simply M31, is captured in full in this February 2010 image from WISE. credit: NASA/JPL-Caltech/UCLA
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The WISE (Wide-field Infrared Survey Explorer) mission isn’t wasting any time in making observations and releasing images. Already the new infrared observatory has spied its first comet and first near Earth asteroid, and today released a “sweet” collection of eye candy from across the universe. “We’ve got a candy store of images coming down from space,” said Edward (Ned) Wright of UCLA, the principal investigator for WISE. “Everyone has their favorite flavors, and we’ve got them all.”
Four new, processed pictures illustrate a sampling of the mission’s targets — a bursting star-forming cloud, a faraway cluster of hundreds of galaxies, a wispy comet, and above, the grand Andromeda galaxy as we’ve never seen it before, with new details of its ringed arms of stars .
NGC 3603, as seen by WISE. credit: NASA/JPL-Caltech/UCLA
Another image shows a bright and choppy star-forming region called NGC 3603, lying 20,000 light-years away in the Carina spiral arm of our Milky Way galaxy. This star-forming factory is churning out batches of new stars, some of which are monstrously massive and hotter than the sun. The hot stars warm the surrounding dust clouds, causing them to glow at infrared wavelengths.
Siding Spring Comet via WISE. credit: NASA/JPL-Caltech/UCLA
This image shows the beauty of a comet called Siding Spring. As the comet parades toward the sun, it sheds dust that glows in infrared light visible to WISE. The comet’s tail, which stretches about 10 million miles, looks like a streak of red paint. A bright star appears below it in blue. WISE is expected to find perhaps dozens of comets, and bagged its first one on January 22, 2010. WISE will help unravel clues locked inside comets about how our solar system came to be.
WISE's view of the Fornax Cluster. credit: NASA/JPL-Caltech/UCLA
The fourth WISE picture is of the Fornax cluster, a region of hundreds of galaxies all bound together into one family. These galaxies are 60 million light-years from Earth. The mission’s infrared views reveal both stagnant and active galaxies, providing a census of data on an entire galactic community.
“All these pictures tell a story about our dusty origins and destiny,” said Peter Eisenhardt, the WISE project scientist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “WISE sees dusty comets and rocky asteroids tracing the formation and evolution of our solar system. We can map thousands of forming and dying solar systems across our entire galaxy. We can see patterns of star formation across other galaxies, and waves of star-bursting galaxies in clusters millions of light years away.”
Since WISE began its scan of the entire sky in infrared light on Jan. 14, the space telescope has beamed back more than a quarter of a million raw, infrared images. The mission will scan the sky one-and-a-half times by October. At that point, the frozen coolant needed to chill its instruments will be depleted. However, the team predicts the spacecraft will be still be operational for 3 additional months following the 10 month prime mission.
No word yet from the Phoenix Mars Lander and, really, mission managers don’t expect to hear from the lander. But that doesn’t mean they aren’t trying. Teams are currently attempting to make contact, with another — and final — series of attempts that may occur next month.
“We haven’t heard a peep since late 2008, when a dust storm combined with the onset of winter to end the mission,” said Mark Lemmon from Texas A&M University, who worked with Phoenix’s camera. “But if Phoenix did survive, a revived mission could uncover some of the climate processes in the area around Mars’ North Pole, where most of the water seems to be.”
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Last contact with Phoenix was back in October 2008, and the teams that worked with the lander are holding out hope that some of the electronics on board survived the severe Martian winter, which dwarfs anything seen on Earth (even the Snowmageddons and Snowpocalypses). Temperatures fall to minus-180 degrees for months at a time and carbon dioxide ice likely engulfed the Phoenix lander. Still, Lemmon said he is ready to help take more pictures and analyze more data if the Lander can be restored to life.
“Phoenix accomplished its mission,” he said, “and it was never designed to survive a Martian winter. In winter, heavy amounts of carbon dioxide frost may have accumulated on its solar panels and it is possible they broke off. Without those panels, which give Phoenix its energy source, it’s pretty much powerless. In addition, other parts may have failed in the extreme cold.”
Phoenix landing site, August, 2009. Credit: NASA/JPL/U of Arizona. Annotations by Phil Stooke
The Phoenix Lander, which landed on Mars May 25, 2008, was designed to dig for soil samples and buried ice near Mars’ North Pole. It also studied Mars’ polar weather.
Phoenix returned more than 30,000 images and made several chemical analyses of the soil above the Martian permafrost. Those analyses found carbonate minerals in the soil, showed that the composition of the soil is near that of Earth’s oceans rather than being acidic, and found perchlorates, which are present in soils in Chile’s Atacama desert on Earth, where they are used as food by some species of bacteria.
Recent images from the Mars Reconnaissance Orbiter show frost in the area around Phoenix’s landing site is now dissipating. Last month, the Mars Odyssey spacecraft, which orbits the planet, made 30 attempts to contact Lander. All failed.
Lemmon says the Lander mission was a success by any measurement.
“The soil samples it dug up show several possible energy sources, such as perchlorates,” he adds, “and that discovery will have a big impact on future plans to explore Mars. The weather information Phoenix returned will be very useful in understanding Mars’ climate, and the discovery of water-ice snowfall near the end of the mission is still amazing.”
Cassini's Mimas, from 70,000 km (Credit: NASA/JPL/Space Science Institute)
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On February 13, 2010, Cassini flew by Saturn’s moon Mimas, coming as close as 9,500 km.
It passed directly over Herschel, a giant crater whose creation almost shattered the moon … and which, in its appearance in some earlier images, earned Mimas the nickname “Death Star”, after the iconic Star Wars prop.
The Cassini team has just released some “Raw Previews” of Cassini’s close encounter; time to feast your eyes.
35,000 km-distant Herschel, from Cassini (unprocessed image; credit: NASA/JPL/Space Science Institute)
The Cassini Equinox Mission, of which the Mimas flyby is but a small part, is a joint United States and European endeavor. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL. The imaging team consists of scientists from the US, England, France, and Germany. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo. Herschel, from 16,000 km above (unprocessed image; credit: NASA/JPL/Space Science Institute)
Source: CICLOPS (Cassini Imaging Central Laboratory for Operations)
A multiwavelength look at Cas A. Credit: NASA/DOE/Fermi LAT Collaboration
The origin of cosmic rays has been a mystery since their discovery nearly a century ago. But new images from the Fermi Gamma-ray Space Telescope may bring astronomers a step closer to understanding the source of the Universe’s most energetic particles. The images show where supernova remnants emit radiation a billion times more energetic than visible light. “Fermi now allows us to compare emission from remnants of different ages and in different environments,” said Stefan Funk, an astrophysicist at the Kavli Institute for Particle Astrophysics and Cosmology (KIPAC).
Cosmic rays are made up of electrons, positrons and atomic nuclei and they constantly bombard the Earth. In their near-speed-of-light journey across the galaxy, the particles are deflected by magnetic fields, which scramble their paths and mask their origins. When cosmic rays collide with interstellar gas, they produce gamma rays. While instruments can infer the presence of cosmic rays by looking for the glow of gamma ray emissions, so far, no specific sources have been located. .
“Understanding the sources of cosmic rays is one of Fermi’s key goals,” said said Funk, who presented the new images and findings at the American Physical Society meeting in Washington, D.C. on Monday.
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Fermi’s Large Area Telescope (LAT) mapped billion-electron-volt (GeV) gamma rays from three middle-aged supernova remnants — known as W51C, W44, and IC 443 — that were never before resolved at these energies. (The energy of visible light is between 2 and 3 electron volts.) Each remnant is the expanding debris of a massive star that blew up between 4,000 and 30,000 years ago.
In addition, Fermi’s LAT also spied GeV gamma rays from Cassiopeia A (Cas A), a supernova remnant only 330 years old. Ground-based observatories, which detect gamma rays thousands of times more
energetic than the LAT was designed to see, have previously detected Cas A.
“Older remnants are extremely bright in GeV gamma rays, but relatively faint at higher energies. Younger remnants show a different behavior,” explained Yasunobu Uchiyama, a Panofsky Fellow at SLAC. “Perhaps the highest-energy cosmic rays have left older remnants, and Fermi sees emission from trapped particles at lower energies.” Fermi mapped GeV-gamma-ray emission regions (magenta) in the W44 supernova remnant. The features clearly align with filaments detectable in other wavelengths. This composite merges X-ray data (blue) from the Germany/U.S./UK ROSAT mission, infrared (red) from NASA’s Spitzer Space Telescope, and radio (orange) from the Very Large Array near Socorro, N.M. Credit: NASA/DOE/Fermi LAT Collaboration, NASA/ROSAT, NASA/JPL-Caltech, and NRAO/AUI
In 1949, physicist Enrico Fermi — for whom the Fermi telescope was named –suggested that the highest-energy cosmic rays were accelerated in the magnetic fields of gas clouds. In the decades that followed,
astronomers showed that supernova remnants are the galaxy’s best candidate sites for this process.
Young supernova remnants seem to possess both stronger magnetic fields and the highest-energy cosmic rays. Stronger fields can keep the highest-energy particles in the remnant’s shock wave long enough to speed them to the energies observed.
The Fermi observations show GeV gamma rays coming from places where the remnants are known to be interacting with cold, dense gas clouds.
“We think that protons accelerated in the remnant are colliding with gas atoms, causing the gamma-ray emission,” Funk said. An alternative explanation is that fast-moving electrons emit gamma rays as they fly past the nuclei of gas atoms. “For now, we can’t distinguish between these possibilities, but we expect that further observations with Fermi will help us to do so,” he added.
Either way, these observations validate the notion that supernova remnants act as enormous accelerators for cosmic particles.
“How fitting it is that Fermi seems to be confirming the bold idea advanced over 60 years ago by the scientist after whom it was named,” noted Roger Blandford, director of KIPAC.
Mission Specialists Nicholas Patrick and Robert Behnken work outside the International Space Station during the second spacewalk of the STS-130 mission. Credit: NASA TV
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(Editor’s Note: Ken Kremer is at the Kennedy Space Center for Universe Today covering the flight of Endeavour)
Astronauts Robert Behnken and Nicholas Patrick completed the second of their three spacewalks (EVAs) planned for the STS-130 mission early this Sunday morning Feb 14 at 3:14 AM EST. The pair worked essentially as plumbers today during the spacewalk which began at 9:20 PM Saturday night. They successfully accomplished all their assigned tasks overnight by connecting crucial Tranquility feed lines to the International Space Station (ISS).
“It was an extremely exciting and successful day on the International Space Station, one that I’m very proud of,” said Flight Director Bob Dempsey. “The team has been working for over two years to make today happen. And it did, and it was extremely successful and I’m very pleased with the way it has gone. Everything was accomplished as we had planned.”
The main goal of EVA 2 was to route four newly redesigned ammonia coolant lines from the new Tranquility life support module to the Destiny laboratory module thereby hooking Tranquility into the space stations existing cooling system. Tranquility could not be fully activated and powered up for use by the ISS crew until fulfilling this essential plumbing job to install the custom built ammonia lines.
Behnken and Patrick spent the first half of EVA-2 connecting the four external ammonia jumper hoses which convey ammonia that works as a coolant to dissipate heat generated by the electronics and systems inside the module. The set up is comprised of two independent loops (A and B) with two lines each, a supply and a return line. The 16 ft long flex lines were also routed through brackets on the Unity node to which Tranquility is attached on the left side. Newly attached Tranquility and Cupola modules (center, left) jut out from the main line of habitable ISS modules running from left to right at center. Credit: NASA TV
After connecting the four jumper hoses the astronauts methodically wrapped them with a long sheet of protective multi layer insulation, or MLI. During the EVA, the astronauts then flipped open the control valves for one of the two external loops (A) and successfully initiated the flow of ammonia coolant though the newly installed set of custom hoses. The second “B” loop will be activated on the third, and last, spacewalk of the STS 130 mission.
NASA astronauts Terry Virts (right), STS-130 pilot; Nicholas Patrick (left) and Stephen Robinson, both mission specialists, are pictured in the newly-installed Tranquility node of the International Space Station . Credit: NASA
With coolant flowing as intended, another team of astronauts inside the ISS began powering up and fully activating the stations newest room for the first time. They turned on the interior lights, ventilation, air conditioning, computers and other life support and environmental control systems which this room was specifically designed to house.
Once again the highly trained and professional astronauts made an extremely difficult job look relatively easy. The only problem was quite minor. Patrick reported that a small quantity of ammonia of leaked out of a reservoir as he uncapped a connector on the Unity module before he could hook up the jumper hose. He said that ammonia particles, which had solidified in the cold vacuum of space, splashed onto the exterior of his spacesuit. This spray of ammonia automatically qualifies as a contamination incident although Patrick did not find any particles actually adhering to his suit. The pair had been trained for exactly this occurrence since a tiny leakage of this type was not entirely unexpected. The spacewalk continued as planned.
Since ammonia is highly toxic, the spacewalkers took care to “bake out” their suits and test for any residual contamination when they arrived back at the airlock at the conclusion of the EVA. None was detected and they ingressed the station as planned.
The final tasks of EVA 2 involved outfitting the nadir docking port of Tranquility for the relocation of the Cupola module to another berthing port and installing exterior handrails.
The Story behind the Urgently Redesigned Ammonia Hoses
NASA and contractor teams had to work quite swiftly to redesign and construct four new custom ammonia hoses. The arduous task was only completed a few days before the then targeted launch date of Feb. 7. Otherwise a significantly curtailed mission involving only partial activation of Tranquility or a launch delay or would have been necessitated.
At the Kennedy Space Center press site I spoke with Eric Howell of Boeing in detail about the intense effort to construct and certify the hoses for the External Active Thermal Control System (EATCS). I had the opportunity to inspect the flexible metal hoses and their individual components first hand and hold and touch them with my own hands. I was quite surprised to find that they were rather sharp and easily capable of causing a deadly air leak gash into a spacewalkers glove.
“The 1 inch diameter hoses are constructed of Inconel, which is resistant to a highly corrosive substance like ammonia. The flexible, convoluted tube is covered by a metal braid which carries the entire load and provides all the strength to maintain the tubes integrity and prevent it from bursting. The individual strands of wire are 1/11,000 inch in diameter,” Howell explained to me.
“Normally it takes about 9 months to design and test the ammonia hoses. We had to get this job done in about 25 days. There was a weld quality issue with the original set of flight hoses. The weld was separating (yielding) from the metal braid carriers under pressure testing with nitrogen. To fix the hose bursting problem, we changed the design of the weld and the welding process to obtain a full depth of penetration.” Redesigned ammonia coolant line and components on display at The KSC press center. Credit: Ken Kremer
“The hoses are designed to operate at 500 psi. To qualify for flight they are tested for 25 cycles at 2000 psi (4 x operating pressure). The original hoses burst at 1600 psi. So we redesigned the hoses and modified the nut collar at the end which we found was too short.”
“We constructed four new multi-segmented hoses built by splicing together 3 to 5 shorter segments which we found lying around in storage throughout several NASA centers. Each of the original hoses that failed were constructed from two segments. The outer metal braid was then covered by a fiberglass sleeve to provide thermal protection. The new hoses were rush shipped from NASA Marshall Spaceflight Center in Huntsville, Ala on Jan 29 after a final checkout for approval by the Endeavour spacewalkers who were quite concerned,” Howell concluded.
Side view of the Tranquility and Cupola modules during my visit inside the Space Station Processing Facility (SSPF) at the Kennedy Space Center. The Cupola is covered by protective blankets and sports two grapple fixtures for the robotic arms to latch onto. Delivery of the modules is the primary goal of the STS130 flight of shuttle Endeavour. The two modules combined weigh over 13.5 tons. Tranquility has six docking ports and is 7 meters (21 ft) in length and 4.5 meters (14.7 ft) in diameter with a pressurized volume of 75 cubic meters (2650 cubic ft). Credit: Ken Kremer
Cupola Relocation and Extra day in Space
Transfer of the Cupola, which had been scheduled for this evening (Sunday, Feb 14) has been put on hold pending resolution of a clearance issue on Tranquilities end docking port to which Cupola is currently attached. The astronauts were unable to attach a protective cover onto the port from inside Tranquility. Several protruding bolts are interfering with attempts to lock the cover in place. The cover shields the port from debris and extreme temperatures when nothing is attached to it.
The astronauts did receive other very good news today when NASA managers decided to extend the STS 130 flight by one day bringing it to14 days in all and thus allowing a total of 9 days of joint docked operations with Endeavour at the orbiting outpost.
The extra flight day will permit Endeavour’s crew additional time to move the space toilet, water recycling, oxygen generation and exercise equipment into the now activated Tranquility. Those relocations had been on hold pending the repairs to the urine recycling system conducted earlier in the flight, and enough run time on the system to generate needed samples for return to Earth for analysis. Landing at the Kennedy Space Center is now targeted for 10:24 PM on Feb 21, weather permitting.
Update: NASA gave the go ahead late this afternoon (Feb 14) to start relocating Cupola late this evening. Watch for a report upon completion sometime overnight.
Earlier STS 130/ISS and SDO articles by Ken Kremer
