Posted on by Mark Mortimer

Book Review: Light This Candle

As much he was an astronaut, Alan Shepard was first a military man. Graduating from Annapolis in the closing stages of World War II, he strove to satisfy his addiction to the new fangled flying machines of his youth. Emerging as a carrier pilot then test pilot, he never flew any military missions. Nevertheless, he contributed significantly by evaluating new planes, establishing new flying techniques and extolling the life of the macho flier. Getting to be the ‘best of the best of the best’ wasn’t natural though. Thompson shows us a very troubled beginning. Shepard almost failed out of the Naval Academy, finally graduating, but, closer to the middle than the top of the class. Equally, he nearly got expelled from the navy’s flyer training program at Corpus Christi because of inadequate progress. On review, it is certainly apparent that Alan Shepard was much more a self-driven person than a natural. With a goal in target, he’d exert all his physical, emotional and sometimes devious energy to succeed, but he didn’t seem to always have a goal.

Yet, time and again Thompson shows Shepard’s determination. Descriptions of his youth show a person pushed to achieve his goals rather than receive them on a platter. Needing a bicycle to make regular visits to an airport, his parents gave him chickens to produce eggs and sell. Needing to satisfy his ambition to fly after getting medically grounded, he found a novel surgical technique to remedy his symptoms of M?ni?res’s disease. Don’t get the idea that Shepard was superhuman. Continual references show a hard drinking, womanizing, Type A personality confronting peers and superiors. Frequent instances of flat hatting demonstrate a consideration of rules as more guidelines than limits. Thompson ably shows these and the many superlatives of Shepard’s life in the event filled times in which he lived.

And as the title suggests, Thompson has an equally admirable ability to depict those times. World War II, Pearl Harbour and Okinawa stress the trials of Shepard’s pre-flight days in the navy. Background descriptions of Corsairs, landing signal officers (LSO) and night time carrier landings surround Shepard in his initiation to naval flight. Vilifications of NASA’s early days arise when engineering knowledge was slightly trailing the science and often barely a half step ahead of training. Shepard’s endeavours to sell scrub and swamp land to unknowing home buyers bring to mind catch phrases about salesmen of yor. Keep in mind that Shepard’s Redstone flight was about 15 minutes and his Apollo14 flight about 7 days, so this book, as with Shepard’s life, includes much, much more than the usual public portrayal of one of the early astronauts in the United States’ space program.

Also peppered throughout the book are references to many luminaries and dignitaries. Descriptions and undertakings of the Mercury Seven abound. Kings and queens, presidents and politicians enter and travel along with Shepard in his lifetime. Golf stories with fellow duffers and pros abound, while social evenings with dignitaries and Hollywood socialites allude to the intermingling amongst the famous. Though with fame of course comes the down side as Thompson shows how Shepard was as often a puppet for the government as a strongman propped up for the public. This unveiled view exemplifies the humanness of even this exemplary person.

A good biography places the reader like a shadow beside the subject to fabricate an image of the life and personality. Thompson does an eloquent and effective job in this with a well researched and well referenced perspective of Allan Shepard’s life and times. Though the writer’s largess might perhaps provide a bit too descriptive a narrative at times, there is no doubt as to the his take on how Shepard lived and effected the life and times of people throughout the world.

What makes a perfect astronaut? Selecting who has the right stuff to fly in space would challenge any selection process. Yet, every person is unique; imperfections and flaws blend with natural ability and desire. Alan Shepard, the second person in space and great contributor to the United States space program, had the fortune and aptitude to walk on the moon and live a very gifted and at times harrowing life. Neal Thompson presents a smooth, richly endowed biography of Shepard’s life in his book Light This Candle and through a great story, show’s that an imperfect person can become a perfect astronaut.

Read more reviews, or purchase a copy online from Amazon.com.

Review by Mark Mortimer.

Posted on by Fraser Cain

Exoplanet Image Confirmed

The brown dwarf 2M1207 and its planetary companion. Image credit: ESO/VLT/NACO. Click to enlarge.
An international team of astronomers reports today confirmation of the discovery of a giant planet, approximately five times the mass of Jupiter, that is gravitationally bound to a young brown dwarf. This puts an end to a year long discussion on the nature of this object, which started with the detection of a red object close to the brown dwarf.

In February and March of this year, the astronomers took new images of the young brown dwarf and its giant planet companion with the state-of-the-art NACO instrument on ESO’s Very Large Telescope in northern Chile. The planet is near the southern constellation of Hydra and approximately 200 light years from Earth.

“Our new images show convincingly that this really is a planet, the first planet that has ever been imaged outside of our solar system,” tells Gael Chauvin, astronomer at ESO and leader of the team of astronomers who conducted the study.

“The two objects – the giant planet and the young brown dwarf – are moving together; we have observed them for a year, and the new images essentially confirm our 2004 finding,” says Benjamin Zuckerman, UCLA professor of physics and astronomy, member of NASA’s Astrobiology Institute, and a member of the team. “I’m more than 99 percent confident.” The separation between the planet and the brown dwarf is 55 times the separation of the Earth and Sun.

Anne-Marie Lagrange, another member of the team from the Grenoble Observatory in France, looks towards the future: “Our discovery represents a first step towards one of the most important goals of modern astrophysics: to characterize the physical structure and chemical composition of giant and, eventually, terrestrial-like planets.”

Last September, the same team of astronomers reported a faint reddish speck of light in the close vicinity of a young brown dwarf (see ESO PR 23/04). The feeble object, now called 2M1207b, is more than 100 times fainter than the brown dwarf, 2M1207A. The spectrum of 2M1207b presents a strong signature of water molecules, thereby confirming that it must be cold. Based on the infrared colours and the spectral data, evolutionary model calculations led to the conclusion that 2M1207b is a 5 Jupiter-mass planet. Its mass can be estimated also by use of a different method of analysis, which focuses on the strength of its gravitational field; this technique suggests that the mass might be even less than 5 Jupiters.

At the time of its discovery in April 2004, it was impossible to prove that the faint source is not a background object (such as an unusual galaxy or a peculiar cool star with abnormal infrared colours), even though this appeared very unlikely. Observations with the Hubble Space Telescope, obtained in August 2004, corroborated the VLT/NACO observations, but were taken too soon after the NACO ones to conclusively demonstrate that the faint source is a planet.

The new observations show with high confidence that the two objects are moving together and hence are gravitationally bound.

“Given the rather unusual properties of the 2M1207 system, the giant planet most probably did not form like the planets in our solar system,” says Gael Chauvin. “Instead it must have formed the same way our Sun formed, by a one-step gravitational collapse of a cloud of gas and dust.”

The paper describing this research has been accepted for publication in Astronomy and Astrophysics.

The same European/American team has had another paper just accepted for publication in Astronomy & Astrophysics; this paper reports the imaging discovery with the same VLT/NACO instrumentation of a lightweight companion to AB Pictoris, a young star located about 150 light years from Earth. The estimated mass of the companion is between 13 and 14 times the mass of Jupiter, which places the companion right on the border line between massive planets and the lowest mass brown dwarfs.

Original Source: ESO News Release

Posted on by Fraser Cain

Time to Concentrate on Saturn’s Rings

Cassini view of Saturn’s rings. Image credit: NASA/JPL/SSI. Click to enlarge.
The Cassini spacecraft is about to embark on a new mission phase that will give it a ringside seat at Saturn — literally. After concentrating on flybys of the stately planet’s moons since arriving last year, Cassini will begin five months of extensive study of Saturn’s magnificent rings. Knowing how the rings form and how long they have been there is a central question for the Cassini mission.

Cassini will view the rings on their lit and unlit faces, both toward the Sun and away from the Sun. This range of geometries will allow all of Cassini’s various instruments to observe the rings as never before.

This grand mosaic consists of 126 images acquired in a tile-like fashion, covering one end of Saturn’s rings to the other and the entire planet in between.

Saturn’s Crown Jewels
From a distance, the majestic rings of Saturn look like symmetrical hoops surrounding the planet. Up close, however, the rings turn out to be a splendid but somewhat unruly population of ice and rock particles jostling against each other or being pushed and pulled into uneven orbits by bigger particles and by Saturn’s many moons.

Their origin is a mystery. Scientists think the rings did not form out of the initial cloud of gas and dust that surrounded Saturn as it formed, but are actually much younger than the planet. However, they do not know if the rings formed after an incoming comet was torn apart by Saturn’s gravity, or if some previous moon of Saturn was smashed to bits by an incoming comet.

Although the rings stretch over 282,000 kilometers (175,000 miles) — about three-fourths of the distance from Earth to the moon — they may be as little as 30 meters (roughly 100 feet) in thickness. The mass of all the ring particles measured together would comprise a moon about the size of Mimas, one of Saturn’s medium-small moons. The rings may in fact be at least partly composed of the remnants of such a moon or moons, torn apart by gravitational forces.

Named in order of discovery, the labels scientists have assigned to the major rings do not indicate their relative positions. From the planet outward, they are known as the D, C, B, A, F, G and E rings.

The images that make up this composition were obtained from Cassini’s vantage point beneath the ring plane with the narrow angle camera on June 21, 2004, at a distance of 6.4 million kilometers (4 million miles) from Saturn.

Running Rings Around Saturn
Cassini’s tour of Saturn has been planned to include three ring observation periods. Much of Cassini’s flight path so far has been along the plane of the rings, where basically the spacecraft sees the rings edge-on.

The first sequence of ring observations, about to begin, runs through early September and will take Cassini seven times around Saturn and its rings. These orbits will be inclined from the ring plane by 24 degrees. The second set of ring orbits occurs between summer 2006 and summer 2007, when the inclination gets up to 53 degrees. Late in the Cassini tour, starting in the fall of 2007, the third set of inclined orbits begins, and by the end of the mission in summer 2008, the inclination of the orbit reaches nearly 80 degrees. This will mean viewing the rings from almost straight above.

Naturally, many new images will be taken, including the first complete global studies of several interesting regions in the rings, including the kinky F ring. Some other first-time events are: high-resolution, full-color images of the rings; radio wavelength mapping of the rings, using Cassini’s main antenna; in-depth studies of thermal emission from the rings over a range of geometries; complete, high-resolution radial scans of the rings in near-infrared, which will provide information on composition of the rings. There will also be a number of new “occultations” of stars by the rings, when stars pass behind the rings from Cassini’s point of view; these will be studied by two different instruments. Also in store are the first occultations by the rings of Cassini’s radio signal, meaning that the signal will pass through the rings en route from the spacecraft to Earth. These will be studied at three radio wavelengths.

During these occultations, scientists will watch how a beam of light from a star or the radio waves from Cassini’s transmitter are affected by the ring material as they pass through the ring. Each occultation experiment provides an opportunity for an extremely high-resolution study of a single path across the rings with resolutions of about 100 meters (330 feet) – some even have resolution as fine as 10 to 20 meters (33 to 66 feet). NASA’s two Voyager spacecraft conducted one radio occultation and one stellar occultation by the rings. During its lifetime, Cassini will obtain 14 radio occultations and 80 stellar occultations, giving far more detailed studies of the ring structures.

The radio experiments will use Cassini’s radio antennas and the ground-based antennas of NASA’s Deep Space Network. From these measurements, scientists can derive information about the structures, composition, densities and sizes of ring particles. New moons may also be discovered from their effects on the ring material.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Near Perfect “Einstein Ring” Discovered

Near perfect “Einstein Ring” gravitational lens. Image credit: ESO/VLT. Click to enlarge.
This is Einstein’s Year. One-hundred years ago a little known Swiss patent clerk in the very early years of a scientific career was confronted with a series of paradoxes related to time and space, energy and matter. Gifted with a profound intuition and a powerful imagination, Albert A. Einstein rose out of obscurity to present an entirely new way of looking at natural phenomenon. Einstein showed us all that time had very little to do with clocks, energy has less to do with quantity and more to do with quality, space was not just ?a big square box to put stuff in”, matter and energy were two sides of the same cosmic coin, and gravity had a profound effect on everything – light, matter, time, and space.

Today we use all these principles ? enunciated a century ago – to probe the most distant things in the Universe. Because of Einstein’s investigation of the photoelectric effect, we now understand why light is not continuous but curiously riddled with dark and bright lines telling us when that light was emitted, what emitted it. and the kinds of things touching it in its travels. Because of Einstein’s insight into the conversion of mass and energy, we now understand how distant suns illuminate the cosmos, and how powerful magnetic fields whip particles up to stupendous speeds later to come crashing down on the Earth’s atmosphere. And because gravity is now understood to influence everything, we have learned how distant objects can capture and focus light from even more distant objects.

Although we have yet to find an absolutely perfect instance of gravitational lensing in the Universe, today we are much closer to that ideal. In a paper entitled “Discovery of a high red-shift Einstein Ring” published April 27, 2005, Remi Cabanac of Canada-France-Hawaii Telescope, in Hawaii and associates “report the discovery of a partial Einstein ring … produced by a massive (and seemingly isolated) elliptical galaxy.” Previous to this find, the most complete Einstein ring discovered was documented in 1996 by S.J. Warren of the Imperial College in London. That ring – also one of the few visible in optical light – is slightly less than a half-circle in circumference (170 degrees).

Remi Cabanac explained that he “discovered the system while observing at the European Southern Observatory Very Large Telescope in Chile with a spectro imager called FORS1.” Remi says he was fullfilling his responsibilties as a service astronomer, “observing for Helmut Jerjen (co-author of the paper) doing deep imaging of nearby dwarf galaxies in the outskirts of a well-known nearby galaxy cluster in Fornax.” Remi continued to say that his “eye got attracted by the very unusual bright arc in the northwest of the field, I knew it was something pretty amazing because lensing arcs are usually very dim, and I was observing in red band whereas arcs are usually blueish.”

To confirm his suspicions of a new discovery Remi “went to the astronomical database but nothing existed under the coordinates.” Later Remi consulted with “Chris Lidman (another co-author and lens expert) and showed him the image. He couldn’t believe it was a lens at first because it was so bright and conspicuous, Chris thought it could be an artefact on the image.” With Chris’ support, Remi “applied for spectroscopic follow-up and realized that it was both a true gravitational lense and a very significant discovery, because the background source was highly amplified and very far away.”

According to the paper, the ring inscribes a “C-shaped” circle of 270 degrees in near-complete circumference with an apparent radius of slightly more than 1 3/4 arc seconds – roughly the size of a star’s “virtual” image seen at high power through a small amateur telescope. The lens galaxy is a giant elliptical similar to M87 in the Virgo-Coma cluster. The lens lies some 7 billion light years distant in the direction of the constellation Fornax (visible from warmer temperate northern hemisphere and southern hemisphere skies). The source galaxy bears a red shift of 3.77 – suggesting a recessionary distance of roughly 11 BLYs. Source and lens galaxy have received the designation FOR J0332-3557 3h32m59s, -35d57m51s and lie proximate to the Fornax galaxy cluster – but well beyond it in terms of real space.

What makes this particular discovery so interesting astronomically is the fact that the lens galaxy is very massive, is in a period of star-birth quiescence, lies at such a great distance from the Earth, and may be isolated from other cluster galaxies in its own spatial locale. Meanwhile the source galaxy is significantly brighter (by one absolute stellar magnitude) than other Lyman break galaxies (galaxies that red-shift the Lyman Break at 912 angstroms into the visible part of the spectrum), is poor in emission line spectra, and recently had completed a cycle of rapid star birth (“starburst”). All these factors combined mean that FOR J0332 could provide a wealth of data concerning galaxy formation before the current inflationary epoch of the Universe.

According to the science team, “One of the key issues in galaxy formation within the current LCDM (Lambda Cold Dark Matter) framework of structure formation is the mass assembly histories of galactic halos.” Current thinking is that galaxies accumulate halo mass – that huge spherical bulge of low luminosity matter surrounding galactic cores – before star formation really kicks in. One way to investigate this idea is to determine how mass-to-light ratios change over time as galaxies evolve. But to do that you need to sample the masses and luminosities of as many galaxies as possible, of a variety of types, over the broadest possible range of space and time.

The discovery of FOR J0332 – and the three other partial Einstein ring objects – helps astronomers by adding examples of galaxies normally undetectable at great distances. From the paper, “Various deep surveys have uncovered different galaxy populations, but the selection criteria produced biased samples: UV-selected and narrow-band selected samples are sensitive to actively star-forming galaxies and biased against quiescent, evolved systems while sub-millimeter and near-infrared surveys select dusty starburst galaxies and very red galaxies respectively.”

What conclusions can we draw based on this discovery?

Remi underscores the significance of this find by saying “The source amplified by the lens is the galaxy with the brightest apparent luminosity ever discovered at such a distance. It will give us unique information on the physical conditions prevailing in the interstellar medium when the universe was only 12% of its present age. The shape of the source is also very important because it gives the amount of mass within the lens at a redshift of z=1. Only a handful of Einstein rings have been discovered at such high redshift. It will give an important measurement at how elliptical galaxy mass evolved through time.”

Written by Jeff Barbour

Posted on by Fraser Cain

Robots Will Search for Lunar Water Deposits

NASA is gearing up to send humans back to the Moon. Image credit: Pat Rawlings / SAIC. Click to enlarge.
The next time you look at the Moon, pause for a moment and let this thought sink in: People have actually walked on the Moon, and right now the wheels are in motion to send people there again.

The goals this time around are more ambitious than they were in the days of the Apollo program. NASA’s new Vision for Space Exploration spells out a long-term strategy of returning to the Moon as a step toward Mars and beyond. The Moon, so nearby and accessible, is a great place to try out new technologies critical to living on alien worlds before venturing across the solar system.

Whether a moonbase will turn out to be feasible hinges largely on the question of water. Colonists need water to drink. They need water to grow plants. They can also break water apart to make air (oxygen) and rocket fuel (oxygen+hydrogen). Furthermore, water is surprisingly effective at blocking space radiation. Surrounding the ‘base with a few feet of water would help protect explorers from solar flares and cosmic rays.

The problem is, water is dense and heavy. Carrying large amounts of it from Earth to the Moon would be expensive. Settling the Moon would be so much easier if water were already there.

It’s possible: Astronomers believe that comets and asteroids hitting the Moon eons ago left some water behind. (Earth may have received its water in the same way.) Water on the Moon doesn’t last long. It evaporates in sunlight and drifts off into space. Only in the shadows of deep cold craters could you expect to find any, frozen and hidden. And indeed there may be deposits of ice in such places. In the 1990s two spacecraft, Lunar Prospector and Clementine, found tantalizing signs of ice in shadowed craters near the Moon’s poles–perhaps as much as much as a cubic kilometer. The data were not conclusive, though.

To find out if lunar ice is truly there, NASA plans to send a robotic scout. The Lunar Reconnaissance Orbiter, or “LRO” for short, is scheduled to launch in 2008 and to orbit the Moon for a year or more. Carrying six different scientific instruments, LRO will map the lunar environment in greater detail than ever before.

“This is the first in a string of missions,” says Gordon Chin, project scientist for LRO at NASA’s Goddard Space Flight Center. “More robots will follow, about one per year, leading up to manned flight” no later than 2020.

LRO’s instruments will do many things: they’ll map and photograph the Moon in detail, sample its radiation environment and, not least, hunt for water.

For example, the spacecraft’s Lyman-Alpha Mapping Project (LAMP), will attempt to peer into the darkness of permanently shadowed craters at the Moon’s poles, looking for signs of ice hiding there.

How can LAMP see in the dark? By looking for the dim glow of reflected starlight.

LAMP senses a special range of ultraviolet light wavelengths. Not only is starlight relatively bright in this range, but also the hydrogen gas that permeates the universe radiates in this range as well. To LAMP’s sensor, space itself is literally aglow in all directions. This ambient lighting may be enough to see what lies in the inky blackness of these craters.

“What’s more, water ice has a characteristic spectral ‘fingerprint’ in this same range of ultraviolet light, so we’ll get spectral evidence of whether ice is in these craters,” explains Alan Stern, a scientist at the Southwest Research Institute and principal investigator for LAMP.

The spacecraft is also equipped with a laser that can shine pulses of light into dark craters. The main purpose of the instrument, called the Lunar Orbiter Laser Altimeter (LOLA), is to produce a highly accurate contour map of the entire Moon. As a bonus, it will also measure the brightness of each laser reflection. If the soil contains ice crystals, as little as 4%, the returning pulse would be noticeably brighter.

LOLA by itself can’t prove that ice is there. “Any kind of reflective crystals could produce brighter pulses,” explains David Smith, principal investigator for LOLA at NASA’s Goddard Space Flight Center. “But if we see brighter pulses only in these permanent shadows, we’d strongly suspect ice.”

One of LRO’s instruments, named Diviner, will map the temperature of the Moon’s surface. Scientists can use these measurements to search for places where ice could exist. Even in the permanent shadows of polar craters, temperatures must be very low for ice to resist evaporation. Thus, Diviner will provide a “reality check” for LRO’s other ice-sensitive instruments, identifying areas where positive signs of ice would not make any sense because the temperature is simply too high.

Another reality check will come from LRO’s Lunar Exploration Neutron Detector (LEND), which counts neutrons spraying out of the lunar surface. Why does the Moon emit neutrons? And what does that have to do with water? The Moon is constantly bombarded by cosmic rays, which produce neutrons when they hit the ground. Hydrogen-bearing compounds like H2O absorb neutrons, so a dip in neutron radiation could signal an oasis … of sorts. LEND is being developed by Igor Mitrofanov from the Institute for Space Research, Federal Space Agency, Moscow.

“There’s a strong synergy between the various instruments on LRO,” notes Chin. “None of these instruments alone could provide definitive evidence of ice on the Moon, but if they all point to ice in the same area, that would be compelling.”

Chin also points out another reason that finding ice near the Moon’s poles would be exciting:

Not far from some permanently shadowed craters are mountainous regions in permanent sunlight, known romantically as “peaks of eternal sunshine.” Conceivably, a moonbase could be placed on one of those peaks, providing astronauts with constant solar power–not far from crater-valleys below, rich in ice and ready to be mined.

Wishful thinking? Or a reasonable plan? Lunar Reconnaissance Orbiter will beam back the answer.

Original Source: Science@NASA Story

Posted on by Fraser Cain

Mars Express Radar Boom to Be Deployed in May

MARSIS on board ESA’s Mars Express will employ ground-penetrating radar to map underground water. Image credit: ESA. Click to enlarge.
Following green light for the deployment of ESA?s Mars Express radar, given in February this year, the radar booms are now planned to be deployed in the first half of May.

Once the deployment is successful, the Mars Express MARSIS radar will enable the first European spacecraft to orbit Mars to complement its study of the planet?s atmosphere and surface.

MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding instrument) is the first antenna of its kind which was also designed to actually look below the surface of Mars at the different layers of material, most notably for water.

The deployment of the three MARSIS radar booms is an operation which will take place in three phases, in a window spanning from 2 to 12 May 2005. These operations will be initiated and monitored from ESA?s European Space Operations Centre (ESOC) in Darmstadt, Germany.

Each boom will be deployed separately, with the two 20-metre ?dipole? booms to be unfurled first and the 7-metre ?monopole? boom to follow a few days later.

Before each deployment, the spacecraft will be placed in a ?robust? attitude control mode, which will allow it to tumble freely while the boom extends before regaining standard pointing to the Sun and Earth.

After each deployment, the control team will conduct a full assessment of the spacecraft status before a decision is taken to proceed with the next phase.

The result of each deployment can be assessed only after a series of tests, each taking few days. After the deployment of the three booms, ESA engineers will start the analysis of the complete behaviour of the satellite to be able to confirm the overall success of the operation.

The current schedule is subject to changes, because the timing of the complex series of operations cannot be all fixed beforehand. A status report will follow in due course.

Once the deployment is complete, MARSIS will undergo three weeks of commissioning before the start of actual science investigations, ready for when one of the prime regions of interest for radar observations comes into the right position through the natural evolution of the spacecraft?s orbit.

The MARSIS instrument was developed by the University of Rome, Italy, in partnership with NASA?s Jet Propulsion Laboratory (JPL) in Pasadena, California, USA.

Original Source: ESA News Release

Posted on by Fraser Cain

Tithonium Chasma on Mars

Tithonium Chasma, a major trough at the western end of the Valles Marineris canyon on Mars. Image credit: ESA. Click to enlarge.
This image, taken by the High Resolution Stereo Camera (HRSC) on board ESA?s Mars Express spacecraft, shows part of Tithonium Chasma, a major trough at the western end of the Valles Marineris canyon on Mars.

The image was taken during orbit 887 with a ground resolution of approximately 13 metres per pixel.

The displayed region is located at the beginning of the canyon system at about latitude 5? South and longitude 280? East. North is to the right of the image.

Tithonium Chasma extends roughly from east to west and runs parallel to Ius Chasma. It ranges from approximately 10 to 110 kilometres wide, narrows in an easterly (top to bottom) direction and has a maximum depth of about 3.5 to 4 kilometres.

The colour image covers the eastern part of Tithonium Chasma. Along the slopes of the trough (centre), linear features due to erosion are visible. At the base of the northern wall (on the right of the black and white image), an apron of material has a longitudinal ridge pattern and may have been caused by a large landslide (see close-up, right).

Dune fields are scattered throughout the trough, including the north-east portion of a crater. A string of depressions on the plains in the south-west of the image may be caused by surface collapse. These features are common to this region and extend parallel to Valles Marineris.

Nearby, prominent linear features are visible and may be faults associated with the formation of the Tharsis Rise, located to the west of Valles Marineris and extending to a height of 8 to 10 kilometres. Some of these faults can be seen faintly extending into the trough.

In the eastern part of the trough, an interesting hill exhibits linear features. These structures are highlighted in the following close-up and perspective views and could have been caused by fluvial or ‘aeolian’ (wind-related) erosion. The darker material to the south of this hill is thought to be underlying material that has been exposed by wind erosion.

By cutting deep into the Martian surface, this area of Valles Marineris provides a window into geological and climatic history of the planet. Valles Marineris has had a complex evolution and has been shaped by tectonic, volcanic and glacial processes, as well as possibly fluvial or aeolian erosion.

Data from the HRSC, coupled with information from the other instruments on ESA?s Mars Express and other missions, will provide new insights into the geological evolution of the Red Planet and also pave the way for future missions.

Original Source: ESA News Release

Posted on by Fraser Cain

Deep Impact Has Its Target in View

Deep Impact’s first view of Comet Temple 1 from a distance of 64 million kilometers (39.7 million miles). Image credit: NASA/JPL. Click to enlarge.
Sixty-nine days before it gets up-close-and-personal with a comet, NASA’s Deep Impact spacecraft successfully photographed its quarry, comet Tempel 1, from a distance of 64 million kilometers (39.7 million miles).

The image, the first of many comet portraits it will take over the next 10 weeks, will aid Deep Impact’s navigators, engineers and scientists as they plot their final trajectory toward an Independence Day encounter. “It is great to get a first glimpse at the comet from our spacecraft,” said Deep Impact Principal Investigator Dr. Michael A’Hearn of the University of Maryland, College Park, Md. “With daily observations beginning in May, Tempel 1 will become noticeably more impressive as we continue to close the gap between spacecraft and comet. What is now little more than a few pixels across will evolve by July 4 into the best, most detailed images of a comet ever taken.”

The ball of dirty ice and rock was detected on April 25 by Deep Impact’s medium resolution instrument on the very first attempt. While making the detection, the spacecraft’s camera saw stars as dim as 11th visual magnitude, more than 100 times dimmer than a human can see on a clear night.

“This is the first of literally thousands of images we will take of Tempel 1 for both science and navigational purposes,” said Deputy Program Manager Keyur Patel at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “Our goal is to impact a one-meter long (39-inch) spacecraft into about a 6.5-kilometer wide (4-mile) comet that is bearing down on it at 10.2 kilometers per second (6.3 miles per second), while both are 133.6 million kilometers (83 million miles) away from Earth. By finding the comet as early and as far away as we did is a definite aid to our navigation.”

To view the comet image on the Internet, visit http://www.nasa.gov/deepimpact or http://deepimpact.jpl.nasa.gov/.

Deep Impact is comprised of two parts, a “flyby” spacecraft and a smaller “impactor.” The impactor will be released into the comet’s path for a planned high-speed collision on July 4. The crater produced by the impact could range in size from the width of a large house up to the size of a football stadium and from 2 to 14 stories deep. Ice and dust debris will be ejected from the crater, revealing the material beneath.

The Deep Impact spacecraft has four data collectors to observe the effects of the collision – a camera and infrared spectrometer comprise the high resolution instrument, a medium resolution instrument, and a duplicate of that camera on the impactor (called the impactor targeting sensor) that will record the vehicle’s final moments before it is run over by comet Tempel 1 at a speed of about 37,000 kilometers per hour (23,000 miles per hour).

The overall Deep Impact mission management for this Discovery class program is conducted by the University of Maryland. Deep Impact project management is handled by the Jet Propulsion Laboratory. The spacecraft was built for NASA by Ball Aerospace & Technologies Corporation, Boulder, Colo.

For more information about Deep Impact on the Internet, visit NASA Deep Impact.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

ESA Astronaut Will Visit Station for Months

ESA astronaut Thomas Reiter from Germany, will be the first to do a long-duration spaceflight. Image credit: ESA. Click to enlarge.
This July, ESA astronaut Thomas Reiter from Germany is about to become the first European to live and work on the International Space Station (ISS) on a long-duration mission.

ESA Director of Human Spaceflight, Microgravity and Exploration, Daniel Sacotte, recently signed an agreement on the mission with the Head of the Russian Federal Space Agency (Roscosmos), Anatoli Perminov. “The agreement covers the ESA astronaut?s flight in a crew position originally planned for a Russian cosmonaut”, explained Sacotte, “and he will perform all the tasks originally allocated to the second Russian cosmonaut on board the ISS and, in addition, an ESA experimental programme.”

The agreement forms part of a set of bilateral understandings between Roscosmos and NASA and between ESA and NASA, enabling the implementation of the mission.

Thomas Reiter, the astronaut assigned to the mission, is a member of the European Astronaut Corps, based at ESA’s European Astronaut Centre (EAC) in Cologne, Germany. L?opold Eyharts, from France, a member of the same Corps, will be the back-up for this mission.

Reiter will reach the ISS on Space Shuttle flight STS-121 currently planned for next July, and return to Earth on flight STS-116 in February.

This will be Reiter’s second long-duration mission on board a space station, following his six-month stay on the Russian Mir, ten years ago, during the ESA Euromir 1995 mission.

“With the maiden flight of the Automated Transfer Vehicle (ATV) and the launch of the European laboratory Columbus, both in 2006, ESA is making important contributions to the ISS and its scientific capabilities and, consequently, we are assuming significant operational responsibilities in this programme. I am confident that this mission will give Europe a lot of operational experience and scientific results which will further prepare us for the exciting and challenging times ahead,” said Thomas Reiter.

“Moreover,” L?opold Eyharts pointed out, “as the back-up astronaut for this mission, I am receiving the same training as Thomas Reiter, which will be an excellent preparation for my tasks as prime astronaut for a future ESA mission to the ISS in connection with Columbus.”

Both astronauts are already in training for the mission in the various ISS training facilities at Houston, Moscow and Cologne, together with their Russian and American astronaut colleagues.

“For the first time, and as a test for later European long-duration missions to the ISS, mission preparation, training, operations and multilateral coordination will be carried out as far as possible through the multilateral decision-making and management structures established for ISS exploitation,” underlined ESA’s Mission Manager Aldo Petrivelli.

“This will be an excellent opportunity for testing coordination and cooperation between ground control and support centres like the Houston and Moscow Mission Control Centres, the Columbus Control Centre in Oberpfaffenhofen, near Munich (*), the European Astronaut Centre in Cologne and the various User Support and Operations Centres throughout Europe that will be involved in the mission. The operational teams from ESA, national space agencies, industry and research institutions in Europe will thus gain very useful operational experience, also for future Columbus system, subsystems and payload operations.”

Original Source: ESA News Release

Posted on by Fraser Cain

Chandra Sees a Bridge Between Stars

Chandra X-Ray view of Mira AB; a red giant star probably orbiting a white dwarf. Image credit: Chandra. Click to enlarge.
For the first time an X-ray image of a pair of interacting stars has been made by NASA’s Chandra X-ray Observatory. The ability to distinguish between the interacting stars – one a highly evolved giant star and the other likely a white dwarf – allowed a team of scientists to observe an X-ray outburst from the giant star and find evidence that a bridge of hot matter is streaming between the two stars.

“Before this observation it was assumed that all the X-rays came from a hot disk surrounding a white dwarf, so the detection of an X-ray outburst from the giant star came as a surprise,” said Margarita Karovska of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., and lead author article in the latest Astrophysical Journal Letters describing this work. An ultraviolet image made by the Hubble Space Telescope was a key to identifying the location of the X-ray outburst with the giant star.

X-ray studies of this system, called Mira AB, may also provide better understanding of interactions between other binary systems consisting of a “normal” star and a collapsed star such as a white dwarf, black hole or a neutron star, where the stellar objects and gas flow cannot be distinguished in an image.

The separation of the X-rays from the giant star and the white dwarf was made possible by the superb angular resolution of Chandra, and the relative proximity of the star system at about 420 light years from Earth. The stars in Mira AB are about 6.5 billion miles apart, or almost twice the distance of Pluto from the Sun.

Mira A (Mira) was named “The Wonderful” star in the 17th century because its brightness was observed to wax and wane over a period of about 330 days. Because it is in the advanced, red giant phase of a star’s life, it has swollen to about 600 times that of the Sun and it is pulsating. Mira A is now approaching the stage where its nuclear fuel supply will be exhausted, and it will collapse to become a white dwarf.

The internal turmoil in Mira A could create magnetic disturbances in the upper atmosphere of the star and lead to the observed X-ray outbursts, as well as the rapid loss of material from the star in a blustery, strong, stellar wind. Some of the gas and dust escaping from Mira A is captured by its companion Mira B.

In stark contrast to Mira A, Mira B is thought to be a white dwarf star about the size of the Earth. Some of the material in the wind from Mira A is captured in an accretion disk around Mira B, where collisions between rapidly moving particles produce X-rays.

One of the more intriguing aspects of the observations of Mira AB at both X-ray and ultraviolet wavelengths is the evidence for a faint bridge of material joining the two stars. The existence of a bridge would indicate that, in addition to capturing material from the stellar wind, Mira B is also pulling material directly off Mira A into the accretion disk.

Chandra observed Mira with its Advanced CCD Imaging Spectrometer on December 6, 2003 for about 19 hours. NASA’s Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for NASA’s Science Mission Directorate, Washington. Northrop Grumman of Redondo Beach, Calif., was the prime development contractor for the observatory. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass.

Additional information and images are available at:

http://chandra.harvard.edu and http://chandra.nasa.gov

Original Source: Chandra News Release