Posted on by Fraser Cain

Radio Astronomy Will Get a Boost With the Square Kilometer Array

The project plans are being developed by a consortium of institutions headed up by Cornell, and funded by the National Science Foundation among others. The SKA plans are loosely based on the ideas being implemented by the Allen Telescope Array (ATA). The ATA is an array of 350 six meter dishes funded by Microsoft philanthropist Paul Allen specifically for SETI research. Note that the science and technology for using interferometers for radio has now reached a stage where this instrument can be built. While this transcontinental technique may be employable for microwaves in the decades ahead, infrared, optical, and x-ray interferometers (several connected telescopes) still require a short direct path of the light to follow, so that the images can be combined using optical, not electronic, means.

The 1.4 billion dollar SKA project should have a final design, and locations defined by 2007, with construction beginning by 2010, and it should be complete and operational by 2015. The array itself will have a core central array of 3300 dishes, and 160 outlying stations of about 7 dishes each covering a broad area of North and Central America.

When complete this tool will have the sensitivity of a single dish, 800 meters in diameter, which is on the order of a hundred times more sensitive than any steerable dish on the planet today. It is also about ten times the sensitivity of the giant dish at Arecibo, which is also operated by Cornell. At its shortest wavelength, the array will be able to image sources to a scale of 500 micro-arcseconds, which is about 15 light-years at the Andromeda galaxy [M31], or a few hundred AU when mapping nearby molecular clouds in our own galaxy.

With all this new detection capability will come a great deal of new science. This month, peer review journals and other sources are getting ready to print numerous papers proposing work that can be done with this instrument. Some of the science goals will help us observe the universe before the first stars formed, and will answer detailed questions about an epoch much earlier than will be seen by the upcoming James Webb Space Telescope. Among the science goals are: Mapping the star formation history and large-scale structure of the Universe, tracing the star formation history over cosmological time, and studying of the Sunyaev-Zel’dovich effect at high redshifts, which some say may have contaminated observed Cosmic Microwave background radiation, and altered the apparent age and dark matter density of the universe. Many of these observations will be done looking at the highly redshifted 21-cm line from neutral hydrogen.

Other science goals include tracing out the magnetic field structure in parsec to Megaparsec jets, in normal galaxies and in distant clusters of galaxies, as well as locate distant (z > 2) clusters, probing strong gravitational fields and the cosmological evolution of super-massive black holes, identifying radio transients 100 times fainter than we can now see, probing the scintillating universe and exploiting super-resolution phenomena, identifying the overall structure, discrete components, and turbulent and magnetic properties of the Milky Way and nearby galaxies, a Milky Way census of faint old pulsars and other compact objects, searching for brown dwarfs in the local Galactic environs and mapping thermal emission from nearby stars, as well as inventorying and tracking solar system debris such as asteroids, comets, and KBOs.

A recent paper points out that the SKA can be used to receive data rates hundreds of times faster than the current Deep Space Network from very distant space probes for short periods, such as from the ESA?s proposed tiny Pluto Orbiter Probe, or NASA?s New Horizons mission to the Kuiper belt.

The SKA will be a versatile instrument with capabilities far beyond what are available in today?s instruments. For radio astronomy, the SKA is the shape of things to come.

Links:
SKA site
SKA Design strawman paper
Allen Telescope Array website

Author: John A. Cross

Posted on by Mark Mortimer

Book Review: The Depths of Space; The Story of the Pioneer Planetary Probes

The Pioneer space probes, brought to fruition by the staff of NASA’s Ames facility, were a series of eight very similar craft. Their main claims to scientific fame included a litany of firsts in space travel and exploration. Though these probes began in the same era as the ‘all encompassing’ manned lunar flights, they happily and necessarily served a different purpose. Happily as in people realized that manned space flight is not the best tool for exploration; there were cheaper mechanical probes. Necessarily as in Ames had just been absorbed into NASA and needed to create a niche for itself or be in danger of disappearing altogether. Thus began the Pioneer odyssey.

Prior to absorption, Ames had been an effective and very responsive academic styled institute. Its staff solved problems very well but expected the problems to be handed to them on a silver platter. At that time, under NACA, they were considered some of the best theoreticians in their field. On becoming a part of NASA, Ames couldn’t sit back when proactive facilities like JPL were overwhelming the spot light. Charles Hall, an Ames staffer, took on the challenge of altering the mind set at Ames as well as the altering the beliefs of the bureaucrats at NASA. With convincing financial and technical arguments, he demonstrated that Ames could effectively manage the design, assembly, test, and operation of a space probe, even if it was to be the first to assess conditions outside of the Earth’s protective shield. Hall turned out to be the right person at the right place and at the right time for his arguments succeeded and Ames began a new direction as space craft designers and builders.

Much of the success of the Pioneer program was directly tied to Hall. Long before ‘faster, better, cheaper’ became the mantra in vogue, Hall lived and breathed this axiom. Technically he did it in two ways. The first way was to have a clearly defined purpose for each probe and each sub-system within the probe. He then fixated on this purpose, and only monumental persuasion convinced him to accept any modifications or redesigns. In consequence, the typical cost run ups and time over runs were all but absent. The second way Hall accomplished this was to stay true to the KISS (keep it simple stupid) principle. Where at all possible, only proven technology and components were used. Simple solutions, such as stabilizing a satellite with spinning, won out over complex ones that used thrusters in each of three axes. Hall’s other forte aside from program management was his political skill, especially with principle investigators. Whether refereeing the battles for the satellites’ download bandwidth or brokering for ever scarce time on the Deep Space Network (DNS), Hall had a knack of finding an amenable solution that kept his program on time and on target. As much as these were and are the better styles of management, when all was said and done, it was the final product and its success that vindicated Hall’s style and direction.

Pioneer probes 6 through 9 were launched between the years 1966 and 1969. They had a design minimum lifetime of six months. However, as 1970 rolled around, Hall was using all these in operating the first space based weather monitoring network. Pioneer 9 still operated up to 1983! Pioneer 10 and 11 were, of course, the well known path finders; the first to ever reach out beyond Mars. Their mission design was to reach Jupiter and assess its surroundings. Yet, both these probes were allowed and able to travel on and were functioning well past Pluto. Only recently has their signal strength gotten so low that the DNS is unable to detect it against background. This is testament enough for the abilities of Hall and everyone else who worked on the Pioneer missions. However, to complete the picture, don’t forget Pioneers 12 and 13. They were directed inwards, to Venus where they provided some of the best observations and measurements of Venus to date. All these Pioneer probes had Hall’s guiding light and all had remarkably successful missions.

Mark Wolverton’s book The Depths of Space provides a very readable and pleasant historical look at some of the significant issues surrounding the Pioneer space probes. Though perhaps by the end a bit repetitious in its accolades, it contains excellent views into some of the significant trials, tribulations and credos for humankind’s first spacecraft to go boldly where none had gone before. Yes, there may have been sketches of naked humans placed upon them but these probes were much more than mere messages in a bottle.

Read more reviews and buy the book online from Amazon.com.

Review by Mark Mortimer

Posted on by Fraser Cain

Robotic Telescopes Team Up

British astronomers are celebrating a world first that could revolutionise the future of astronomy. They have just begun a project to operate a global network of the world’s biggest robotic telescopes, dubbed ‘RoboNet-1.0’ which will be controlled by intelligent software to provide rapid observations of sudden changes in astronomical objects, such as violent Gamma Ray Bursts, or 24-hour surveillance of interesting phenomena. RoboNet is also looking for Earth-like planets, as yet unseen elsewhere in our Galaxy.

Progress in many of the most exciting areas of modern astronomy relies on being able to follow up unpredictable changes or appearances of objects in the sky as rapidly as possible. It was this that led astronomers at Liverpool John Moores University (LJMU) to pioneer the development of a new generation of fully robotic telescopes, designed and built in the UK by Telescope Technologies Ltd.. Together the Liverpool Telescope (LT) and specially allocated time on the Faulkes North (FTN), soon to be joined by the Faulkes South (FTS), make up RoboNet-1.0.

Commenting on the need for a network of telescopes RoboNet Project Director, Professor Michael Bode of LJMU said “Although each telescope individually is a highly capable instrument, they are still limited by the hours of darkness, local weather conditions and the fraction of the sky each can see from its particular location on planet Earth.”

Prof. Bode added “Astronomical phenomena are however no respecters of such limitations, undergoing changes or appearances at any time, and possibly anywhere on the sky. To understand certain objects, we may even need round-the-clock coverage – something clearly impossible with a single telescope at a fixed position on the Earth’s surface.”

Thus was born the concept of “RoboNet” – a global network of automated telescopes, acting as one instrument able to search anywhere in the sky at any time and (by passing the observations of a target object from one telescope to the next in the network) being able to do so continuously for as long as is scientifically important.

The first mystery RoboNet will examine is the origin of Gamma Ray Bursts (GRBs). Discovered by US spy satellites in the late 1960’s, these unpredictable events are the most violent explosions since the Big Bang, far more energetic than supernova explosions. Yet they are extremely brief, lasting from milliseconds to a few minutes, before they fade away to an afterglow lasting a few hours or weeks. Their exact cause is still unknown, although the collapse of supermassive stars or the coalescence of exotic objects such as black holes and neutron stars are prime candidates. To study GRBs, telescopes need to be pointed at the right area of the sky extremely quickly.

In October this year, NASA will launch a new satellite named Swift, in which the UK has a major involvement, and which will pinpoint the explosions of GRBs on the sky more accurately and rapidly than ever before. The co-ordinates of each burst will be relayed to telescopes on the Earth, including those of RoboNet, within seconds of their occurrence, at the rate of one event every few days. Telescopes within the UK’s new RoboNet network are designed to respond automatically within a minute of an alert from Swift. It is in the first few minutes after the burst that observations are urgently required to enable astronomers to really understand the cause of these immense explosions, but until now such observations have been extremely difficult to secure.

RoboNet’s second major aim is to discover Earth-like planets around other stars. We now know of more than 100 extra-solar planets. However, all of these are massive planets (like Jupiter) and many are too near to their parent star, and hence too hot, to support life. RoboNet will take advantage of a phenomenon called gravitational microlensing (where light from a distant star is bent and amplified around an otherwise unseen foreground object) to detect cool planets. When a star that is being lensed in this way has a planet, it causes a short ‘blip’ in the light detected, which rapid-reacting telescopes such as the RoboNet network can follow up. In fact, the network stands the best chance of any existing facility of actually finding another Earth due to the large size of the telescopes, their excellent sites and sensitive instrumentation.

The Particle Physics and Astronomy Research Council (PPARC) have funded the establishment of RoboNet-1.0, based around using the three giant robotic telescopes at their sites across the globe. The “glue” that holds all this together is software developed by the LJMU-Exeter University “eSTAR” project, allowing the network to act intelligently in a co-ordinated manner.

Dr Iain Steele of the eSTAR project says “We have been able to use and develop new Grid technologies, which will eventually be the successor to the World Wide Web, to build a network of intelligent agents that can detect and respond to the rapidly changing universe much faster than any human. The agents act as “virtual astronomers” collecting, analysing and interpreting data 24 hours a day, 365 days a year, alerting their flesh-and-blood counterparts only when they make a discovery.”

If successful, RoboNet could be expanded to the development of a larger, dedicated global network of up to six robotic telescopes.

Professor Michael Bode of Liverpool John Moores University adds “We have led the world in the design and build of the most advanced robotic telescopes and now with RoboNet-1.0 we are set to lead the way in some of the most challenging and exciting areas of modern astrophysics”.

Original Source: PPARC News Release

What is the biggest telescope in the world?

Posted on by Fraser Cain

NASA Hopeful About Finding Science in Genesis Wreckage

Scientists who conducted the preliminary assessment of the Genesis canister are encouraged by what they see. They believe it may be possible to achieve the most important portions of their science objectives.

“We are bouncing back from a hard landing, and spirits are picking up again,” said Orlando Figueroa, deputy associate administrator for programs for the Science Mission Directorate at NASA Headquarters in Washington.

“This may result in snatching victory from the jaws of defeat,” added Dr. Roger Wiens of the Los Alamos National Laboratory in New Mexico, a member of the Genesis science team. “We are very encouraged.” Based on initial inspection, it is possible a repository of solar wind materials may have survived that will keep the science community busy for some time.

“We are pleased and encouraged by the preliminary inspection,” said NASA Administrator Sean O’Keefe. “The outstanding design and sturdy construction of Genesis may yield the important scientific results we hoped for from the mission.”

“I want to emphasize the excellent work by the navigation team to bring the capsule back exactly on target was key in our ability to recover the science,” said Andrew Dantzler, director of the Solar System Division at NASA Headquarters, Washington. “In addition, the robustness of the design of the spacecraft was the reason it could take such a hard landing and still give us a chance to recover the samples.”

The mission’s main priority is to measure oxygen isotopes to determine which of several theories is correct regarding the role of oxygen in the formation of the solar system. Scientists hope to determine this with isotopes collected in the four target segments of the solar wind concentrator carried by the Genesis spacecraft. “From our initial look, we can see that two of the four concentrator segments are in place, and all four may be intact,” Wiens said.

The mission’s second priority is to analyze nitrogen isotopes that will help us understand how the atmospheres of the planets in our solar system evolved. “These isotopes will be analyzed using gold foil, which we have also found intact,” Wiens said.

Other samples of solar winds are contained on hexagonal wafers. It appears these are all or nearly all broken, but sizable pieces will be recovered, and some are still mounted in their holders. “We won’t really know how many can be recovered for some time, but we are far more hopeful important science can be conducted than we were on Wednesday,” Wiens said.

Another type of collector material, foils contained on the canister’s lid, were designed to collect other isotopes in the solar wind. It appears approximately three-fourths of these are recoverable, according to Dr. Dave Lindstrom, mission program scientist at NASA Headquarters. However, these foils have been exposed to elements of the Utah desert.

The Genesis sample return capsule landed well within the projected ellipse path in the Utah Test & Training Range on Sept. 8, but its parachutes did not open. It impacted the ground at nearly 320 kilometers per hour (nearly 200 miles per hour). NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Genesis mission for the agency’s Science Mission Directorate. Lockheed Martin Space Systems, Denver, developed and operated the spacecraft.

News and information about Genesis is available on the Internet at http://www.nasa.gov/genesis. For background information about Genesis, visit http://genesismission.jpl.nasa.gov. For information about NASA on the Internet, visit http://www.nasa.gov.

Original Source: NASA News Release

Posted on by Fraser Cain

Astronauts Begin Repairing Oxygen System

The oxygen-producing Elektron in of the International Space Station was restarted today after a troubleshooting procedure by Expedition 9 Commander Gennady Padalka, but shut down again after operating for just over an hour.

Russian specialists decided to forego further troubleshooting until Monday to give them more time to determine why a gas analysis mechanism in the system commanded the Elektron to shut down two other times after Padalka had cleaned and flushed lines in the device.

Despite the intermittent performance of the Elektron, there is plenty of oxygen in the Station?s cabin atmosphere. U.S. flight controllers slightly increased nitrogen levels on board with nitrogen from the Quest airlock tanks, but no further repressurization of the cabin atmosphere is required in the near future. The Elektron?s temporary shutdown has no impact to any Station operations.

After several hours of work on the system in the Zvezda Service Module this morning, Padalka told Russian flight controllers that the reassembled Elektron, which separates water into oxygen for the Station and hydrogen that is vented overboard, had twice run for about five minutes before shutting down. Eventually, Padalka and flight controllers disabled an Elektron gas analyzer sensor system, and the device continued to operate for just over an hour before it commanded itself to shut off again. The Elektron originally shut down on Wednesday, prompting Padalka?s maintenance work.

At the moment, Russian flight controllers believe that a modification in the software that regulates commanding for the gas analyzer could fix the problem early next week.

On Wednesday, Padalka used spare parts sent up on a Russian Progress resupply ship last May to bring a spare liquids unit for the Elektron back to operational status. There are no plans to use the backup unit at the moment, but it is available, if needed. The Progress currently docked to the Station has full oxygen and air tanks and additional oxygen is available in two high-pressure tanks on Quest, if they are needed. A total of 84 Solid Fuel Oxygen Generator canisters, a 42-day supply of oxygen for the crew, also are available, but there are no plans to use any reserve oxygen supplies.

Earlier in the week, Padalka and NASA ISS Science Officer Mike Fincke conducted routine housekeeping tasks and a few post-spacewalk tasks, including the stowage of spacewalking tools and the servicing of the Russian Orlan space suits.

Fincke also conducted optional science activities, including some remaining data takes with a Dutch experiment that helps to characterize the performance of a grooved heat pipe in microgravity. The experiment was brought up to the Station by European Space Agency astronaut Andre Kuipers in April.

Both crewmembers worked with other science and medical experiments this week. Padalka conducted the PLANTS experiment as well as the PROFILAKTIKA experiment. It is designed to study countermeasures to negative physiological effects of lengthy spaceflight.

Fincke also performed proficiency training for the Advanced Diagnostic Ultrasound in Microgravity medical experiment and on Thursday, both crewmembers participated in a bone scanning procedure. That research will not only assist with onboard medical situations but is being developed for possible use in remote areas on Earth.

Padalka and Fincke wrapped up their week with a televised conversation with Native American students at the United Tribes Technical College in Bismarck, ND. It was the featured event during the 35th Annual United Tribes International Powwow. NASA representatives from the Johnson Space Center and the Langley Research Center attended the powwow and tribal meetings to promote NASA education and Explorer Schools.

Padalka and NASA ISS Science Officer Mike Fincke completed their 145th day in space today and their 143rd day aboard the complex.

For information on the crew’s activities aboard the Space Station, future launch dates, as well as a list of opportunities to see the Station from anywhere on the Earth, visit:

http://spaceflight.nasa.gov/

For details on Station science operations provided by the Payload Operations Center at NASA’s Marshall Space Flight Center in Huntsville, Ala., visit:

http://scipoc.msfc.nasa.gov/

The next ISS status report will be issued on Friday, Sept. 17 or earlier, if events warrant.

Original Source: NASA Status Report

Posted on by Fraser Cain

NASA’s Satellite Photo of Hurricane Ivan

Managers and meteorologists at NASA’s Kennedy Space Center (KSC) are closely monitoring Hurricane Ivan as it approaches the United States through the Caribbean Sea.

The latest computer models have the powerful storm moving west and farther away from KSC’s location on Florida’s east central coast (visit the National Hurricane Center for the latest forecasts and tracks).

With forecasters expecting KSC to receive maximum winds around 40 knots and four to six inches of rain from Ivan on Tuesday, NASA managers are planning to reopen KSC to its 14,000 employees Monday, as originally scheduled. With that model in mind, the KSC director will make a final decision about reopening on Sunday.

About 1,500 damage assessment and support personnel have spent the past week working to get KSC operational after last weekend’s hit from Hurricane Frances. Workers are continuing to prepare KSC this weekend for reopening and for Hurricane Ivan.

When KSC opens, about 700 employees will report to alternative worksites, because their buildings were damaged by Frances and require extensive repairs. All KSC employees will have facilities with power, air conditioning, voice and data communications.

NASA will provide updates about the Kennedy Space Center and Hurricane Ivan as new information becomes available. When information for KSC employees is available, it will be posted at http://www.nasa.gov/kennedy.

Original Source: NASA Update

Posted on by Fraser Cain

Station’s Oxygen Generator Breaks Down

A generator that supplies oxygen to the International Space Station has broken down, and it could cause a delay for the upcoming crew transfer scheduled for next month. The Russian-built Elekton generator uses electrolysis to separate oxygen out of waste water, and without it, the two-man crew of the station will need to get their oxygen from the Progress cargo ship currently docked. They’ll attempt repairs to the unit on Friday.

Posted on by Fraser Cain

Astronomers Watch a Black Hole Eat a Meal

Scientists have pieced together the journey of a bundle of doomed matter as it orbited a black hole four times, an observational first. Their technique provides a new method to measure the mass of a black hole; and this may enable the testing of Einstein’s theory of gravity to a degree few thought possible.

A team led by Dr. Kazushi Iwasawa at the Institute of Astronomy (IoA) in Cambridge, England, followed the trail of hot gas over the course of a day as it whipped around the supermassive black hole roughly at the same distance the Earth orbits the Sun. Quickened by the extreme gravity of the black hole, however, the orbit took about a quarter of a day instead of a year.

The scientists could calculate the mass of the black hole by plugging in the measurements for the energy of the light, its distance from the black hole, and the time it took to orbit the black hole — a marriage of Einstein’s general relativity and good old-fashioned Keplerian physics.

Iwasawa and his colleague at the IoA, Dr. Giovanni Miniutti, present this result today during a Web-based press conference in New Orleans at the meeting of the High Energy Astrophysics Division of the American Astronomical Society. Dr. Andrew Fabian of the IoA joins them on an article appearing in an upcoming issue of the Monthly Notices of the Royal Astronomical Society. The data is from the European Space Agency’s XMM-Newton observatory.

The team studied a galaxy named NGC 3516, about 100 million light years away in the constellation Ursa Major, home to the Big Dipper (or, the Plough). This galaxy is thought to harbour a supermassive black hole in its core. Gas in this central region glows in X-ray radiation as it is heated to millions of degrees under the force of the black hole’s gravity.

XMM-Newton captured spectral features from light around the black hole, displayed on a spectrograph with spikes indicating certain energy levels, similar in appearance to the jagged lines of a cardiograph. During the daylong observation, XMM captured a flare from excited gas orbiting the black hole as it whipped around four times. This was the crucial bit of information needed to measure the black hole mass.

The scientists already knew the distance of the gas from the black hole from its spectral feature. (The extent of gravitational redshift, or energy drain revealed by the spectral line, is related to how close an object is to a black hole.) With an orbital time and distance, the scientists could pin down a mass measurement — between 10 million and 50 million solar masses, in agreement with values obtained with other techniques.

While the calculation is straightforward, the analysis to understand the orbital period of an X-ray flare is new and intricate. Essentially, the scientists detected a cycle repeated four times: a modulation in the light’s intensity accompanied by an oscillation in the light’s energy. The energy and cycle observed fit the profile of light gravitationally redshifted (gravity stealing energy) and Doppler shifted (a gain and loss in energy as orbiting matter moves towards and away from us).

The analysis technique implies, to this science team’s surprise, that the current generation of X-ray observatories can make significant gains in measuring black hole mass, albeit with long observations and black hole systems with long-lasting flares. Building upon this information, proposed missions such as Constellation-X or XEUS can make deeper inroads to testing Einstein’s math in the laboratory of extreme gravity.

Original Source: Institute of Astronomy News Release

Posted on by Fraser Cain

Tracking Rainfall, Just By its Gravity

For the first time, scientists have demonstrated that precise measurements of Earth’s changing gravity field can effectively monitor changes in the planet’s climate and weather.

This finding comes from more than a year’s worth of data from the Gravity Recovery and Climate Experiment, or Grace. Grace is a two-spacecraft, joint partnership of NASA and the German Aerospace Center.

Results published in the journal Science show that monthly changes in the distribution of water and ice masses could be estimated by measuring changes in Earth’s gravity field. The Grace data measured the weight of up to 10 centimeters (four inches) of groundwater accumulations from heavy tropical rains, particularly in the Amazon basin and Southeast Asia. Smaller signals caused by changes in ocean circulation were also visible.

Launched in March 2002, Grace tracks changes in Earth’s gravity field. Grace senses minute variations in gravitational pull from local changes in Earth’s mass. To do this, Grace measures, to one-hundredth the width of a human hair, changes in the separation of two identical spacecraft in the same orbit approximately 220 kilometers (137 miles) apart.

Grace maps these variations from month to month, following changes imposed by the seasons, weather patterns and short-term climate change. Understanding how Earth’s mass varies over time is an important component necessary to study changes in global sea level, polar ice mass, deep ocean currents, and depletion and recharge of continental aquifers.

Grace monthly maps are up to 100 times more accurate than existing ones, substantially improving the accuracy of many techniques used by oceanographers, hydrologists, glaciologists, geologists and other scientists to study phenomena that influence climate.

“Measurements of surface water in large, inaccessible river basins have been difficult to acquire, while underground aquifers and deep ocean currents have been nearly impossible to measure,” said Dr. Byron Tapley, Grace principal investigator at the University of Texas Center for Space Research in Austin, Texas. “Grace gives us a powerful new tool to track how water moves from one place to another, influencing climate and weather. These initial results give us great confidence Grace will make critical contributions to climate research in the coming years,” he added.

“The unparalleled accuracy of the Grace measurements opens a number of new scientific perspectives,” said Dr. Christoph Reigber of GeoForschungsZentrum Potsdam in Germany. “Observations of mass variations over the oceans will assist in interpreting annual signals in long-term sea-level change that have become an important climate change indicator,” Reigber said.

Dr. Michael Watkins, Grace project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., said the results mark the birth of a new field of remote sensing. “Over the past 20 years, we’ve made primitive measurements of changes in Earth’s gravity field over scales of thousands of kilometers, but this is the first time we’ve been able to demonstrate gravity measurements can be truly useful for climate monitoring,” he said.

“The Grace gravity measurements will be combined with water models to sketch an exceptionally accurate picture of water distribution around the globe. Together with other NASA spacecraft, Grace will help scientists better understand the global water cycle and its changes,” Watkins added.

The University of Texas Center for Space Research has overall mission responsibility. German mission elements are the responsibility of GeoForschungsZentrum Potsdam. Science data processing, distribution, archiving and product verification are managed under a cooperative arrangement between JPL, the University of Texas and GeoForschungsZentrum Potsdam.

For more information about Grace on the Internet, visit http://www.csr.utexas.edu/grace or http://www.gfz-potsdam.de/grace. For information about NASA programs on the Internet, visit http://www.nasa.gov.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Heavily Eroded Crater on Mars

This image, taken by the High Resolution Stereo Camera (HRSC) on board ESA?s Mars Express spacecraft, shows part of a heavily eroded impact crater at Solis Planum, in the Thaumasia region of Mars.

The image was taken during orbit 431 in May 2004 with a ground resolution of approximately 48 metres per pixel. The displayed region is located south of Solis Planum at longitude 271? East and latitude of about 33? South.

The larger eroded impact crater in the lower left of the image has a diameter of about 53 kilometres and its eastern crater rim is about 800 metres high.

The blue/white tint in the eastern (top left) part of the scene indicates a near-surface haze or clouds.

To the south (right), tectonic ?graben? structures can be seen running in three different directions (north-west, north-east and east-north-east), which show three different phases of development.

A graben is a down-dropped block of the crust resulting from extension, or pulling, of the crust. They are often seen together with features called ?horsts?, which are upthrown blocks lying between two steep-angled fault blocks. Some of the graben shown here are about five kilometres wide.

The northern end of the higher region, or upper left in this image, contains an almost circular plateau, which is 15 kilometres across.

It may be an old impact crater, filled by sediments, which developed a harder consistency than the surrounding material over the course of time.

Later, the more easily eroded material was removed and the harder inner filling remained. This phenomenon is called ?inverted relief?.

Original Source: ESA News Release