Spirit finds hints of past water at Gusev siteMISSION CONTROL REPORT
Posted: April 1, 2004
Clues from a wind-scalloped volcanic rock on Mars investigated by NASA's Spirit rover suggest repeated possible exposures to water inside Gusev Crater, scientists said Thursday.
Gusev is halfway around the planet from the Meridiani region where Spirit's twin, Opportunity, recently found evidence that water used to flow across the surface.
"This is not water that sloshed around on the surface like what appears to have happened at Meridiani. We're talking about small amounts of water, perhaps underground," said Dr. Hap McSween, a rover science team member from the University of Tennessee, Knoxville.
"The evidence is in the form of multiple coatings on the rock, as well as fractures that are filled with alteration material and perhaps little patches of alteration material," McSween said during a press conference at NASA's Jet Propulsion Laboratory, Pasadena, Calif.
The rock, called "Mazatzal" after mountains in Arizona, lies partially buried near the rim of the crater informally named "Bonneville" inside the much larger Gusev Crater. Its light- toned appearance grabbed scientists' attention. After Spirit's rock abrasion tool brushed two patches on the surface with wire bristles, a gray, darker layer could be seen under the tan topcoat. The rock abrasion tool ground into the surface with diamond cutting teeth on March 26. Then, after an examination of the newly exposed material, it ground deeper into the rock two days later. A lighter-gray interior lies under the darker layer, and a bright stripe cuts across both.
Dr. Jeff Johnson, a science team member from the U.S. Geological Survey's Astrogeology Team, Flagstaff, Ariz., said the stripe "seems to be a fracture that water has flowed through, potentially with minerals precipitating from that fluid and lining the walls of the crack."
He and other scientists stressed that the interpretations are preliminary. "The team is, as always, trying to find time to digest these observations while also preparing for the next day's operations," Johnson said.
Spirit's alpha particle X-ray spectrometer checked what chemical elements were close to the surface of untreated, brushed, once-drilled and twice-drilled patches. "Miracles, miracles, miracles. We have a lot of work to do," the instrument's lead scientist, Dr. Rudi Rieder of the Max Planck Institute, Mainz, Germany, exclaimed about the results. For example, the ratio of bromine to chlorine seen inside the rock is unusually high and possibly a clue to alteration by water.
The final experiment on Mazatzal was to scrub the surface with the rock abrasion tool in a pattern of five circles arranged in a ring, with a sixth circle in the center. Besides creating a rock-art daisy, this task by the engineers of New York-based Honeybee Robotics, as well as JPL, produced a brushed patch big enough to fill the field of view of Spirit's miniature thermal emission spectrometer, said Dr. Steve Ruff of Arizona State University, Tempe. The tan outer surface appears to have a strikingly different mineral composition than the dark gray coating exposed by the brushing, but more time is needed to complete the analysis, he said.
McSween proposed that the light outer coat, dark inner coat and bright veins could have resulted from three different periods of the rock being buried, altered by fluids and unburied.
While scientists await transmission of additional data Spirit has collected about Mazatzal, the rover will be making its way toward the "Columbia Hills" about 2.3 kilometers (1.3 miles) away. Spirit left the rock and drove 36.5 meters (120 feet) early Thursday.
Opportunity set a one-day driving record on Mars on March 27 by covering 48.9 meters (160 feet) toward a rock called "Bounce Rock" because airbag bounce marks show that the spacecraft hit it on landing day two months ago. "We're looking to break that record again very soon with longer and longer drives," said JPL's Chris Lewicki, flight director.
Before moving on across the plains of Meridiani, though, Opportunity will complete an investigation it has begun of Bounce Rock. The rock is unlike any seen on Mars before, said Dr. Jim Bell, lead scientist for the rovers' panoramic cameras. "There are some shiny surfaces on this rock," he said, describing them as "almost mirrorlike."
The two rovers' 18 cameras have now taken more than 20,000 images. JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA's Office of Space Science, Washington, D.C.
A bit of self-congratulation from the Europeans--courtesy of the British website "Astronomynow.com" (but they ARE doing good work I must admit):
Happy Anniversary, VLT! Five years at the service of Europe's astronomers
EUROPEAN SOUTHERN OBSERVATORY
Posted: April 1, 2004
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The Very Large Telescope (VLT) is the world's largest and most advanced optical telescope. It comprises four 8.2-metre reflecting Unit Telescopes (UTs) and will in due time also include four moving 1.8-m Auxiliary Telescopes (ATs), the first one of which successfully passed its first tests in January 2004.
In the language of the indigenous Mapuche (Mapudungun) people, the four Unit Telescopes are now known as: ANTU (UT1; The Sun), KUEYEN (UT2; The Moon), MELIPAL (UT3; The Southern Cross), and YEPUN (UT4; Venus - as evening star).
Image credit: ESO
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One of the world's most advanced astronomical research facilities, the ESO Very Large Telescope (VLT) at the Paranal Observatory in the Chilean Atacama desert, has just celebrated an important anniversary.
On April 1, 1999, and following almost one year of extensive tests and careful trimming of its numerous high-tech parts, the first 8.2-metre VLT Unit Telescope, Antu (UT1), was "handed over" to the astronomers. Since that date, science operations with this marvellous research tool have been continuous and intensive. Kueyen (UT2) started normal operations exactly one year later. Yepun (UT4) was offered to the scientific community in June 2001, while Melipal (UT3) followed in August 2001.
Ever since, all four VLT Unit Telescopes, with an ever-growing suite of highly specialised, extremely powerful astronomical instruments have been in full operation, 365 nights a year. And this with unequalled success, as demonstrated by a long list of important scientific results, including a substantial number of exciting discoveries that are now opening new horizons in astrophysics. Moreover, thanks to heroic and persistent efforts by the dedicated teams of ESO scientists and engineers, the "downtime" due to technical problems has been very small, about 3 per cent, a number that is unequalled among the world's large telescope facilities. In addition, the weather conditions at the Paranal site in the dry Atacama desert in Northern Chile are truly excellent - this is indeed one of the best locations for astronomical observations on the surface of the Earth - and the corresponding "weather downtime" has only been around 10 per cent. This has resulted in an unbelievably low value of total downtime, most likely a new world record for ground-based 8-10 metre class telescopes.
VLT strong points:
The Very Large Telescope (VLT) is the world's largest and most advanced optical telescope. It comprises four 8.2-m reflecting Unit Telescopes (UTs) and will in due time also include four moving 1.8-m Auxiliary Telescopes (ATs), the first one of which successfully passed its first tests in January 2004.
With unprecedented optical resolution and unsurpassed surface area, the VLT produces extremely sharp images and can record light from the faintest and most remote objects in the Universe. It works at the limit of modern technology, regularly allowing the scientists to peer into new and unknown territories in the immense universe.
Contrary to other large astronomical telescopes, the VLT was designed from the beginning with the use of interferometry as a major goal. For this reason, the four 8.2-m Unit Telescopes were positioned in a quasi-trapezoidal configuration. The light beams from these telescopes, at this moment two-by-two, can be combined in the VLT Interferometer (VLTI).
It provides the European scientific community with a ground-based telescope array with collecting power significantly greater than any other facilities available at present or being planned, offering imaging and spectroscopy capabilities at visible and infrared wavelengths.
The observational statistics prove that these instruments are extremely efficient - they have some of the highest "shutter-open times" (i.e. percentage of the maximum possible observing time during which the instruments are collecting light from the astronomical objects) ever achieved. The astronomers are well served in this respect: the ISAAC instrument, for example, continues to be in the highest demand and has now performed smoothly during more than 1000 nights and two others, UVES and FORS, are now approaching the same number.
Working together with astronomers and engineers at many research institutes in the ten ESO member countries, ESO is now in the process of defining second generation instruments and feasibility studies are well under way. Among the prime projects in this direction are a cryogenic multi-object spectrometer in the near-infrared 1 to 2.4 µm range ("KMOS"), a medium-resolution wide-band (0.32 to 2.4 µm) spectrometer ("X-shooter"), as well as a wide-field 3D optical spectrometer ("3D deep-field surveyor") and a high-contrast, adaptive optics assisted, imager ("planet finder").
In addition to these highly innovative instruments for the VLT UTs, specific instruments that will work with the combined light from several of the telescopes have also been conceived. The interferometric instrument MIDI will be offered to the astronomical community from April 1st, 2004, fulfilling the VLTI promise. Great efforts have indeed gone into making observations with this very complex science machine as user-friendly as possible. Contrary to what is normally the case in this technically demanding branch of astronomy, scientists will find interferometric work at the VLTI quite similar to that of using the many other, more conventional VLT instruments.
Science with the VLT:
The impressive battery of top-ranking instruments, coupled with the enormous light-collecting power of the VLT, has already provided a real research bonanza with many outstanding scientific results, some of which have been true breakthroughs. They include the amazing new knowledge about the Black Hole at the Galactic Centre, the farthest galaxy known, the most metal-poor and hence, oldest stars, accurate cosmochronological dating by means of Uranium and Thorium spectral lines, high-redshift galaxy rotation curves, micro-quasars, properties of the optical counterparts of gamma-ray bursts, high-redshift supernovae, etc. All of these advances attest to the power of the VLT and its mode of operational. Not to be forgotten is also the beauty of many of the stunning images obtained with this telescope, one of which was voted amongst the 10 most inspirational astronomical images of the past century. Look at the numerous and detailed ESO Press Releases for more examples of research achievements from the VLT.
This trend is also apparent in the productivity of the telescopes. The number of research publications resulting from VLT work in top ranking astronomical journals is steadily increasing with a total close to 700, hereof 250 in 2003 alone. Moreover, research articles based on VLT data are in the mean quoted twice as often as the average.
The very high efficiency of the VLT "science machine" now generates huge amounts of data at a very high rate. These are stored in a permanent Science Archive Facility at ESO headquarters, which is jointly operated by ESO and the Space Telescope European Coordinating Facility (ST-ECF). From here, data are distributed daily to astronomers on DVDs and over the World Wide Web. The archive facility has been conceived and developed to enable astronomers to "mine" very efficiently the enormous volumes of data that is collected from the VLT. The archive now contains more than 1 million images or spectra taken by the four UTs with a total volume of about 50 Terabytes (50,000,000,000,000 bytes) of data. This corresponds to the content of about 25 million books of 1000 pages each; they would occupy more than 1000 kilometres of bookshelves!
Looking towards the future
Says Catherine Cesarsky, ESO Director General since 1999: " The Paranal Observatory has already given rise to an impressive number of scientific results, many of which could not have been obtained elsewhere. Overall, the VLT has been a most remarkable success, and will contribute to science at the highest level for years to come - a fantastic achievement of which we can all be justifiably proud."
The work is now underway at full power to provide second-generation instruments for the VLT, to add three more Auxiliary Telescopes to the VLTI and to complement this unique research facility with the two wide-field survey ("pathfinding") telescopes - one to work in the visible part of the spectrum (the 2.5-metre VST), the other in the infrared (the 4-metre VISTA) - now being constructed at Paranal.
Roberto Gilmozzi, director of Paranal Observatory, looks forward: " Ever more exciting times lie ahead for Paranal with new instruments like VISIR and SINFONI and the laser guide star, all of them coming this year. Five years after the start of operations on UT1, the observatory operates its telescopes with very little time set aside for engineering (less than 10%) and very low technical down time. Combined with excellent weather and great image quality, we provide the European community with unsurpassed observing capabilities. As director of this observatory since 1999, I have been privileged to be part of this adventure."
The VLT is a fine example of the vast benefits of pooling resources from several countries and it is a flagship of contemporary European research. There is little doubt that for many years to come, ESO's Paranal Observatory with its powerful and efficient facilities will continue to play a leading role in astronomical research.
The best of the stunning images produced by the VLT are now available at the Top 20 webpage with printing quality images:
http://www.eso.org/outreach/gallery/vlt/images/Top20/
