Posted on by Fraser Cain

China Launches Second Double Star

Yesterday, 25 July at 09:05 CEST (15:05 local time) the Chinese National Space Administration successfully launched Tan Ce 2, the second of the Double Star science satellites. This marks the latest important milestone in the scientific collaboration between China and the European Space Agency.

Tan Ce (“Explorer”) 2 was launched from the Taiyuan spaceport west of Beijing (Zhangye province) using a Long March 2C rocket. The launch, initially scheduled for today 26 July, took place one day earlier in order to avoid adverse weather conditions expected in the days to come. The spacecraft will join Tan Ce 1, which was launched on 29 December 2003, to complete the Double Star configuration.

About 8 hours after launch the two solid booms holding the magnetometers were successfully deployed. In the next few weeks, all spacecraft sub-systems will be checked out and the commissioning of the on-board scientific instrument will follow.

Double Star will operate alongside ESA?s quartet of Cluster satellites to closely study the interaction between the solar wind and the Earth?s magnetic field. Together, these missions will provide the most detailed view to date. TC-1 is already returning a wealth of scientific data. Back in January, both missions tracked a coronal mass ejection from the Sun and gathered valuable data about the Earth’s bow shock.

Tan Ce 2 reached its nominal orbit, with perigee at 682 km, apogee at 38279 km and inclination of 90.1 deg. The positions and orbit of the Double Star satellites have been carefully defined to enable exploration of the magnetosphere on a larger scale than is possible with Cluster alone. One example of this coordinated activity is the study of the substorms that produce aurorae.

The exact region where these emissions of brightness form is still unclear, but the simultaneous high-resolution measurements combined under these two missions are expected to provide an answer.

ESA is contributing eight scientific instruments to the mission, seven of which are Cluster-derived units.

These are the first ever European experiments to fly on a Chinese satellite. ESA will also be providing ground segment support, four hours each day, via its Villafranca satellite tracking station in Spain.

Scientific cooperation between China and ESA goes back quite a long way. A first Agreement signed back in 1980 facilitated the exchange of scientific information. Thirteen years later, the collaboration focused on a specific mission, Cluster, to study the Earth’s magnetosphere.

Then, in 1997, came a big step forward. The CNSA invited ESA to participate in the Double Star dual-satellite mission to study the Earth?s magnetic field, from a perspective different but complementary to Cluster’s. The Agreement to carry out this joint mission was signed on 9 July 2001 by ESA?s then Director General Antonio Rodot? and CNSA Administrator Luan Enjie.

For Professor David Southwood, ESA?s Science Programme Director: ?Today?s successful launch marks the culmination of these joint efforts and a further important step forward in this historic collaboration between China and Europe.?

Original Source: ESA News Release

Posted on by Fraser Cain

NASA Fights to Save Budget

Image credit: NASA
Administrator Sean O’Keefe today acknowledged the tough financial decisions that have to be made by Congress in passing the fiscal year 2005 budget, but asked the chairman of the U.S. House Committee on Appropriations to restore more than $1 billion of recommended cuts made Tuesday by the appropriations subcommittee.

“Over the course of the past year, Congress has called for the President to articulate a vision and strategy for space exploration. The President’s budget proposes the means to support the Vision for Space Exploration while the Subcommittee’s position does not provide the resources,” said the Administrator in a letter to Committee Chairman C. W. Bill Young, Republican congressman from Florida’s 10th District. “We are encouraged that the Subcommittee endorsed the Vision for Space Exploration in their markup, indicating they are hopeful that it may be possible to augment NASA funding as the appropriations process moves forward.”

Tuesday, members of the subcommittee recommended to the full Appropriations Committee a $15.1 billion budget for NASA, cutting about $1.1 billion from the President’s 2005 fiscal year submission. The NASA budget is part of a $93 billion spending bill that also provides funding for the Department of Veterans Affairs, the Department of Housing and Urban Development, the National Science Foundation and the Environmental Protection Agency.

“The Subcommittee-recommended funding level for NASA would adversely affect its ongoing science and technology programs, as well as the NASA workforce, and will delay plans for FY 2005 critical technology design efforts needed to better define the architecture in support of the Vision for Space Exploration,” the Administrator continued in his letter. “It is very important that these design efforts go forward in FY 2005 to enable NASA to address the long-lead, high-risk requirements that will form the basis for informed decisions by Congress on next steps in the Exploration plan.”

The Administrator thanked Chairman Young for the Appropriation Committee’s support of the Vision for Space Exploration. Administrator O’Keefe said he would continue to seek Committee and Congressional support for full funding of the President’s 2005 budget as the appropriations process continues.

The entire letter may be found on the Internet at:

http://www.nasa.gov/pdf/62799main_072204_young_letter.pdf

Original Source: NASA News Release

Posted on by Fraser Cain

What Venus and Sunspots Have in Common

Scientists using measurements from NASA’s Solar Radiation and Climate Experiment (SORCE) satellite have discovered that Venus and sunspots have something in common: they both block some of the sun’s energy going to Earth.

Using data from NASA’s SORCE satellite, scientists noticed that, when Venus came between the Earth and the sun on June 8, the other planet reduced the amount of sunlight reaching Earth by 0.1 percent. This Venus transit occurs when, from an earthly perspective, Venus crosses in front of the sun. When it happens, once every 122 years, there are two transits eight years apart. The next crossing happens in 2012 and will be visible to people on the U.S. West Coast.

“Because of its distance from Earth, Venus appeared to be about the size of a sunspot,” said Gary Rottman, SORCE Principal Investigator and a scientist at the Laboratory for Atmospheric and Space Physics (LASP), at the University of Colorado at Boulder. The SORCE team had seen similar reductions in the sun’s energy coming Earthward during the October 2003 sunspot activity.

In October 2003 the Earth-bound sunlight dimmed 0.3 percent for about four days, due to three very large sunspot groups moving across the face of the sun.

“This is an unprecedented large decrease in the amount of sunlight, and it is comparable to the decrease that scientists estimate occurred in the seventeenth century,” Rottman said. That decrease lasted almost 50 years, and was likely associated with the exceptionally cold temperatures throughout Europe at that time, a period from the 1400s to the 1700s known as the “little ice age.”

Solar conditions during the little ice age were quite different, as there were essentially no sunspots. Astronomers of the time, like Galileo, kept a good record of sunspot activity before and during the period, encountering only about 50 sunspots in 30 years.

Rottman said, “Something very different was happening during the seventeenth century, and it produced a much more permanent change in the sun’s energy output at that time.” Today, the large sunspots are surrounded by bright areas called “faculae.” Faculae more than compensate for the decrease in sunlight from sunspots, and provide a net increase in sunlight when averaged over a few weeks.

The large number of sunspots occurring in October/November 2003 indicated a very active sun, and indeed many very large solar flares occurred at that time. SORCE observed the massive record-setting solar flares in x-rays. The flares were accompanied by large sunspots, which produced a 0.3 percent decrease in the sun’s energy output. SORCE simultaneously collected the energy from all wavelengths, something that had never been done before.

“The SORCE satellite instruments provide measurements of unprecedented accuracy, so the sun’s energy output is known with great precision, and precise knowledge of variations in the sun’s energy input to Earth is a necessary prerequisite to understanding Earth’s changing climate,” said Robert F. Cahalan, SORCE Project Scientist and Head of the Climate and Radiation Branch at NASA’s Goddard Space Flight Center, Greenbelt, Md.

The SORCE measurements provide today’s atmospheric and climate scientists with essential information on the sun’s energy input to the Earth. These measurements also will be valuable to future scientists, who will be relating their view of the world back to conditions existing today. Likewise Galileo’s findings about the sun almost 400 years ago have increased in value as understanding of the sun and its importance for Earth has advanced.

For more SORCE information and images on the Internet, visit:

hthttp://www.gsfc.nasa.gov/topstory/2004/0730sunblockers.html
and
http://lasp.colorado.edu/sorce/

Original Source: NASA News Release

Posted on by Fraser Cain

Icy Enceladus

Saturn?s brilliant jewel, water-ice-covered Enceladus (499 kilometers, 310 miles across), is the most reflective body in the Solar System. Reflecting greater than 90% of the incident sunlight, this moon was the source of much surprise during the Voyager era. Enceladus exhibits both smooth and lightly cratered terrains that are crisscrossed here and there by linear, groove-like features. It also has characteristics similar to those of Jupiter’s moons, Ganymede and Europa, making one of Saturn’s most enigmatic moons.

Cassini will investigate its rich geologic record in a series of four planned close flybys. The first flyby is scheduled for February 17, 2005.

The image was taken in visible light with the narrow angle camera on July 3, 2004, from a distance of 1.6 million kilometers (990,000 miles) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of about 103 degrees. The image scale is 10 kilometers (6 miles) per pixel. The image has not been magnified.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Office of Space Science, Washington, D.C. The imaging team is based at the Space Science Institute, Boulder, Colorado.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.

Original Source: CICLOPS News Release

Posted on by Fraser Cain

Eclectic Group of Galaxies Captured by Hubble

Like a photographer clicking random snapshots of a crowd of people, NASA’s Hubble Space Telescope has taken a view of an eclectic mix of galaxies. In taking this picture, Hubble’s Advanced Camera for Surveys was not looking at any particular target. The camera was taking a picture of a typical patch of sky, while Hubble’s infrared camera was viewing a target in an adjacent galaxy-rich region.

The jumble of galaxies in this image, taken in September 2003, includes a yellow spiral whose arms have been stretched by a possible collision [lower right]; a young, blue galaxy [top] bursting with star birth; and several smaller, red galaxies.

But the most peculiar-looking galaxy of the bunch ? the dramatic blue arc in the center of the photo ? is actually an optical illusion. The blue arc is an image of a distant galaxy that has been smeared into the odd shape by a phenomenon called gravitational lensing. This “funhouse- mirror effect” occurs when light from a distant object is bent and stretched by the mass of an intervening object. In this case the gravitational lens, or intervening object, is a red elliptical galaxy nearly 6 billion light-years from Earth. The red color suggests that the galaxy contains older, cooler stars.

The distant object whose image is smeared into the long blue arc is about 10 billion light-years away. This ancient galaxy existed just a few billion years after the Big Bang, when the universe was about a quarter of its present age. The blue color indicates that the galaxy contains hot, young stars.

Gravitational lenses can be seen throughout the sky because the cosmos is crowded with galaxies. Light from distant galaxies, therefore, cannot always travel through space without another galaxy getting in the way. It is like walking through a crowded airport. In space, a faraway galaxy’s light will travel through a galaxy that is in the way. But if the galaxy is massive enough, its gravity will bend and distort the light.

Long arcs, such as the one in this image, are commonly seen in large clusters of galaxies because of their huge concentrations of mass. But they are not as common in isolated galaxies such as this one. For the gravitational lens to occur, the galaxies must be almost perfectly aligned with each other.

Gravitational lenses yield important information about galaxies. They are a unique and extremely useful way of directly determining the amount of mass, including dark matter, in a galaxy. Galaxies are not just made up of stars, gas, and dust. An invisible form of matter, called dark matter, makes up most of a galaxy’s mass. A study of this newly discovered system, dubbed J033238-275653, was published in the Astrophysical Journal Letters. This study, together with similar observations, may allow astronomers to make the first direct measurements of the masses of bright, nearby galaxies.

Original Source: Hubble News Release

Posted on by Fraser Cain

Chandra Sees a Star Flare Up

Observations with NASA’s Chandra X-ray Observatory captured an X-ray outburst from a young star, revealing a probable scenario for the intermittent brightening of the recently discovered McNeil’s Nebula. It appears the interaction between the young star’s magnetic field and an orbiting disk of gas can cause dramatic, episodic increases in the light from the star and disk, illuminating the surrounding gas.

“The story of McNeil’s Nebula is a wonderful example of the importance of serendipity in science,” said Joel Kastner of the Rochester Institute of Technology in Rochester, New York, lead author of a paper in the July 22 issue of Nature describing the X-ray results. “Visible-light images were made of this region several months before Jay McNeil made his discovery, so it could be determined approximately when and by how much the star flared up to produce McNeil’s Nebula.”

The small nebula, which lies in the constellation Orion about 1300 light years from Earth, was discovered with a 3-inch telescope by McNeil, an amateur astronomer from Paducah, Kentucky, in January 2004. In November 2002, a team led by Ted Simon of the Institute for Astronomy in Hawaii had observed the star-rich region with Chandra in search of young, X-ray emitting stars, and had detected several objects. Optical and infrared astronomers had, as part of independent surveys, also observed the region about a year later, in 2003.

After the announcement of McNeil’s discovery, optical, infrared and X-ray astronomers rushed to observe the region again. They found that a young star buried in the nebula had flared up, and was illuminating the nebula. This star was coincident with one of the X-ray sources discovered earlier by Simon.

Chandra observations obtained by Kastner’s group just after the optical outburst showed that the source had brightened fifty-fold in X-rays when compared to Simon’s earlier observation. The visible-light eruption provides evidence that the cause of the X-ray outburst is the sudden infall of matter onto the surface of the star from an orbiting disk of gas.

In general, the coupling of the magnetic field of the star and the magnetic field of its circumstellar disk regulates the inflow of gas from the disk onto the star. This slow, steady inflow suddenly can become much more rapid if a large amount of gas accumulates in the disk, and the disk and the star are rotating at different rates.

The differing rotation rates would twist and shear the magnetic field, storing up energy. This energy is eventually released in an energetic, X-ray producing outburst as the magnetic field violently rearranges back to a more stable state. During this period, a large amount of gas can fall onto the star, producing the observed optical and infrared outburst.

A new buildup of gas in the disk could lead to a new outburst in the future. Such a scenario may explain why the brightness of McNeil’s Nebula appears to vary with time. It is faintly present in surveys of this region of Orion in images taken in the 1960s, but absent from images taken in the 1950s and 1990s.

NASA’s Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for NASA’s Office of Space Science, Washington. Northrop Grumman of Redondo Beach, Calif., formerly TRW, Inc., 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.

Original Source: Chandra News Release

Posted on by Fraser Cain

Wallpaper: Saturn’s Rings in Colour

Nine days before it entered orbit, Cassini captured this exquisite natural color view of of Saturn?s rings. The images that comprise this composition were obtained from Cassini?s vantage point beneath the ring plane with the narrow angle camera on June 21, 2004, from a distance of 6.4 million kilometers (4 million miles) from Saturn and a phase angle of 66 degrees. The image scale is 38 kilometers (23 miles) per pixel.

The brightest part of the rings, curving from the upper right to the lower left in the image, is the B ring. Many bands throughout the B ring have a pronounced sandy color. Other color variations across the rings can be seen. Color variations in Saturn’s rings have previously been seen in Voyager and Hubble Space Telescope images. Cassini’s images show that color variations in the rings are more pronounced in this viewing geometry than they are when seen from Earth. Saturn’s rings are made primarily of water ice. Since pure water ice is white, it is believed that different colors in the rings reflect different amounts of contamination by other materials such as rock or carbon compounds. In conjunction with other Cassini instruments, Cassini images will help to determine the composition of different parts of Saturn’s ring system.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Office of Space Science, Washington, D.C. The imaging team is based at the Space Science Institute, Boulder, Colorado.

For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and the Cassini imaging team home page, http://ciclops.org.

Original Source: CICLOPS News Release

Posted on by Fraser Cain

Space Initiative Gets Big Budget Cuts

President Bush’s new space initiative received a major setback this week when the members of a House appropriations subcommittee passed a tentative budget that would fund only a fraction of the President’s new plans. The panel suggested that NASA should receive $15.1 billion next year, which is a drop of $229 million from last year (NASA was actually hoping for a 5.6% increase). Development of the new Crew Exploration Vehicle would be delayed, and funding would be cut to Project Prometheus – a new nuclear propulsion technology. This isn’t a final approved budget, however, as there are many more steps for the final decision is made.

Posted on by Fraser Cain

New Mars Meteorite Discovered

While rovers and orbiting spacecraft scour Mars searching for clues to its past, researchers have uncovered another piece of the red planet in the most inhospitable place on Earth — Antarctica.

The new specimen was found by a field party from the U.S. Antarctic Search for Meteorites program (ANSMET) on Dec. 15, 2003, on an ice field in the Miller Range of the Transantarctic Mountains, roughly 750 km (466 miles) from the South Pole. This 715.2-gram (1.6-pound) black rock, officially designated MIL 03346, was one of 1358 meteorites collected by ANSMET during the 2003-2004 austral summer.

Discovery of this meteorite occurred during the second full field season of a cooperative effort funded by NASA and supported by the National Science Foundation (NSF) to enhance recovery of rare meteorite types in Antarctica, in the hopes new martian samples would be found.

Scientists at the Smithsonian Institution’s National Museum of Natural History involved in classification of Antarctic finds said the mineralogy, texture and the oxidized nature of the rock are unmistakably martian. The new specimen is the seventh recognized member of a group of martian meteorites called the nakhlites, named after the first known specimen that fell in Nakhla, Egypt, in 1911.

Like the other martian meteorites, MIL 03346 is a piece of the red planet that can be studied in detail in the laboratory, providing a critical “reality check” for use in interpreting the wealth of images and data being returned by the spacecraft currently exploring Mars. Following the existing protocols of the U.S. Antarctic meteorite program, scientists from around the world will be invited to request samples of the new specimen for their own detailed research.

Nakhlites are significant among the known martian meteorites for several reasons. Thought to have originated within thick lava flows that crystallized on Mars approximately 1.3 billion years ago, and sent to Earth by a meteorite impact about 11 million years ago, the nakhlites are among the older known martian meteorites. As a result they bear witness to significant segments of the volcanic and environmental history of Mars.

The U.S. Antarctic Meteorite program is a cooperative effort jointly supported by NSF, NASA and the Smithsonian Institution. Antarctic field work is supported by grants from NASA and NSF to Case Western Reserve University, Cleveland; initial examination and curation of recovered Antarctic meteorites is supported by NASA at the astromaterials curation facilities at Johnson Space Center in Houston; and initial characterization and long-term curation of Antarctic meteorite samples is supported by NASA and the Smithsonian Institution at the National Museum of Natural History in Washington.

Details concerning initial characterization of the specimen and sample availability are available through a special edition of the Antarctic Meteorite Newsletter, to be immediately released on the Web at:

Antarctic Meteorite Newsletter

Original Source: NASA News Release

Posted on by Fraser Cain

Satellites Spot Giant Rogue Waves

Once dismissed as a nautical myth, freakish ocean waves that rise as tall as ten-storey apartment blocks have been accepted as a leading cause of large ship sinkings. Results from ESA’s ERS satellites helped establish the widespread existence of these ‘rogue’ waves and are now being used to study their origins.

Severe weather has sunk more than 200 supertankers and container ships exceeding 200 metres in length during the last two decades. Rogue waves are believed to be the major cause in many such cases.

Mariners who survived similar encounters have had remarkable stories to tell. In February 1995 the cruiser liner Queen Elizabeth II met a 29-metre high rogue wave during a hurricane in the North Atlantic that Captain Ronald Warwick described as “a great wall of water? it looked as if we were going into the White Cliffs of Dover.”

And within the week between February and March 2001 two hardened tourist cruisers ? the Bremen and the Caledonian Star ? had their bridge windows smashed by 30-metre rogue waves in the South Atlantic, the former ship left drifting without navigation or propulsion for a period of two hours.

“The incidents occurred less than a thousand kilometres apart from each other,” said Wolfgang Rosenthal – Senior Scientist with the GKSS Forschungszentrum GmbH research centre, located in Geesthacht in Germany – who has studied rogue waves for years. “All the electronics were switched off on the Bremen as they drifted parallel to the waves, and until they were turned on again the crew were thinking it could have been their last day alive.

“The same phenomenon could have sunk many less lucky vessels: two large ships sink every week on average, but the cause is never studied to the same detail as an air crash. It simply gets put down to ‘bad weather’.”

Offshore platforms have also been struck: on 1 January 1995 the Draupner oil rig in the North Sea was hit by a wave whose height was measured by an onboard laser device at 26 metres, with the highest waves around it reaching 12 metres.

Objective radar evidence from this and other platforms ? radar data from the North Sea’s Goma oilfield recorded 466 rogue wave encounters in 12 years – helped convert previously sceptical scientists, whose statistics showed such large deviations from the surrounding sea state should occur only once every 10000 years.

The fact that rogue waves actually take place relatively frequently had major safety and economic implications, since current ships and offshore platforms are built to withstand maximum wave heights of only 15 metres.

In December 2000 the European Union initiated a scientific project called MaxWave to confirm the widespread occurrence of rogue waves, model how they occur and consider their implications for ship and offshore structure design criteria. And as part of MaxWave, data from ESA’s ERS radar satellites were first used to carry out a global rogue wave census.

“Without aerial coverage from radar sensors we had no chance of finding anything,” added Rosenthal, who headed the three-year MaxWave project. “All we had to go on was radar data collected from oil platforms. So we were interested in using ERS from the start.”

ESA’s twin spacecraft ERS-1 and 2 ? launched in July 1991 and April 1995 respectively ? both have a Synthetic Aperture Radar (SAR) as their main instrument.

The SAR works in several different modes; while over the ocean it works in wave mode, acquiring 10 by 5 km ‘imagettes’ of the sea surface every 200 km.

These small imagettes are then mathematically transformed into averaged-out breakdowns of wave energy and direction, called ocean-wave spectra. ESA makes these spectra publicly available; they are useful for weather centres to improve the accuracy of their sea forecast models.

“The raw imagettes are not made available, but with their resolution of ten metres we believed they contained a wealth of useful information by themselves,” said Rosenthal. “Ocean wave spectra provide mean sea state data but imagettes depict the individual wave heights including the extremes we were interested in.

“ESA provided us with three weeks’ worth of data ? around 30,000 separate imagettes ? selected around the time that the Bremen and Caledonian Star were struck. The images were processed and automatically searched for extreme waves at the German Aerospace Centre (DLR).”

Despite the relatively brief length of time the data covered, the MaxWave team identified more than ten individual giant waves around the globe above 25 metres in height.

“Having proved they existed, in higher numbers than anyone expected, the next step is to analyse if they can be forecasted,” Rosenthal added. “MaxWave formally concluded at the end of last year although two lines of work are carrying on from it ? one is to improve ship design by learning how ships are sunk, and the other is to examine more satellite data with a view to analysing if forecasting is possible.”

A new research project called WaveAtlas will use two years worth of ERS imagettes to create a worldwide atlas of rogue wave events and carry out statistical analyses. The Principal Investigator is Susanne Lehner, Associate Professor in the Division of Applied Marine Physics at the University of Miami, who also worked on MaxWave while at DLR, with Rosental a co-investigator on the project.

“Looking through the imagettes ends up feeling like flying, because you can follow the sea state along the track of the satellite,” Lehner said. “Other features like ice floes, oil slicks and ships are also visible on them, and so there’s interest in using them for additional fields of study.

“Only radar satellites can provide the truly global data sampling needed for statistical analysis of the oceans, because they can see through clouds and darkness, unlike their optical counterparts. In stormy weather, radar images are thus the only relevant information available.”

So far some patterns have already been found. Rogue waves are often associated with sites where ordinary waves encounter ocean currents and eddies. The strength of the current concentrates the wave energy, forming larger waves ? Lehner compares it to an optical lens, concentrating energy in a small area.

This is especially true in the case of the notoriously dangerous Agulhas current off the east coast of South Africa, but rogue wave associations are also found with other currents such as the Gulf Stream in the North Atlantic, interacting with waves coming down from the Labrador Sea.

However the data show rogue waves also occur well away from currents, often occurring in the vicinity of weather fronts and lows. Sustained winds from long-lived storms exceeding 12 hours may enlarge waves moving at an optimum speed in sync with the wind ? too quickly and they’d move ahead of the storm and dissipate, too slowly and they would fall behind.

“We know some of the reasons for the rogue waves, but we do not know them all,” Rosenthal concluded. The WaveAtlas project is scheduled to continue until the first quarter of 2005.

Original Source: ESA News Release