Posted on by Fraser Cain

Earth’s Field Opens Up for the Solar Wind

Image credit: NASA

Researchers have discovered that temporary cracks can form in the Earth’s magnetic field that can permit some of the solar wind’s energy to slip through and disrupt electronics and communications. These observations were made using NASA’s Imager for Magnetopause to Aurora Global Exploration (IMAGE) satellite, which tracked a large aurora for several hours. The ESA’s Cluster satellites flew over the same location and spotted a stream of ions slipping through a crack which normally should have been deflected by the Earth’s magnetosphere.

Immense cracks in the Earth’s magnetic field remain open for hours, allowing the solar wind to gush through and power stormy space weather, according to new observations from the IMAGE and Cluster satellites.

The cracks were detected before but researchers now know they can remain open for long periods, rather than opening and closing for just very brief intervals. This new discovery about how the Earth’s magnetic shield is breached is expected to help space physicists give better estimates of the effects of severe space weather.

“We discovered that our magnetic shield is drafty, like a house with a window stuck open during a storm,” said Dr. Harald Frey of the University of California, Berkeley, lead author of a paper on this research published Dec. 4 in Nature. “The house deflects most of the storm, but the couch is ruined. Similarly, our magnetic shield takes the brunt of space storms, but some energy continually slips through its cracks, sometimes enough to cause problems with satellites, radio communication, and power systems.”

“The new knowledge that the cracks are open for long periods, instead of opening and closing sporadically, can be incorporated into our space weather forecasting computer models to more accurately predict how our space weather is influenced by violent events on the Sun,” said Dr. Tai Phan, also of UC Berkeley, co-author of the Nature paper.

The solar wind is a stream of electrically charged particles (electrons and ions) blown constantly from the Sun (Image 1). The solar wind transfers energy from the Sun to the Earth through the magnetic fields it carries and its high speed (hundreds of miles/kilometers per second). It can get gusty during violent solar events, like Coronal Mass Ejections (CMEs), which can shoot a billion tons of electrified gas into space at millions of miles per hour.

Earth has a magnetic field that extends into space for tens of thousands of miles, surrounding the planet and forming a protective barrier to the particles and snarled magnetic fields the Sun blasts toward it during CMEs. However, space storms, which can dump 1,000 billion watts — more than America’s total electric generating capacity — into the Earth’s magnetic field, indicated that the shield was not impenetrable.

In 1961, Dr. Jim Dungey of the Imperial College, United Kingdom, predicted that cracks might form in the magnetic shield when the solar wind contained a magnetic field that was oriented in the opposite direction to a portion of the Earth’s field. In these regions, the two magnetic fields would interconnect through a process known as “magnetic reconnection,” forming a crack in the shield through which the electrically charged particles of the solar wind could flow. (Image 2 illustrates the crack formation, and Animation 1 shows how solar wind particles flow through the crack by following invisible magnetic field lines.) In 1979, Dr. Goetz Paschmann, of the Max Planck Institute for Extraterrestrial Physics, Germany, detected the cracks using the International Sun Earth Explorer (ISEE) spacecraft. However, since this spacecraft only briefly passed through the cracks during its orbit, it was unknown if the cracks were temporary features or if they were stable for long periods.

In the new observations, the Imager for Magnetopause to Aurora Global Exploration (IMAGE) satellite revealed an area almost the size of California in the arctic upper atmosphere (ionosphere) where a 75-megawatt “proton” aurora flared for hours (Image 4). This aurora, energetic enough to power 75,000 homes, was different from the visible aurora known as the Northern and Southern lights. It was generated by heavy particles (ions) hitting the upper atmosphere and causing it to emit ultraviolet light, which is invisible to the human eye but detectable by the Far Ultraviolet Imager on IMAGE. (Image 6 and Animation 4 show IMAGE’s observations of the proton aurora).

While the aurora was being recorded by IMAGE, the 4-satellite Cluster constellation flew far above IMAGE, directly through the crack, and detected solar wind ions streaming through (Image 5). Normally, these solar wind ions would be deflected by Earth’s shield (Image 3), so Cluster’s observation showed a crack was present. This stream of solar wind ions bombarded our atmosphere in precisely the same region where IMAGE saw the proton aurora. The fact that IMAGE was able to view the proton aurora for more than 9 hours, until IMAGE progressed in its orbit to where it could not observe the aurora, implies that the crack remained continuously open. (Animation 2 shows how the spacecraft worked together to reveal the crack.) Estimating from the IMAGE and Cluster data, the crack was twice the size of the Earth at the boundary of our magnetic shield, about 38,000 miles (60,000 km) above the planet’s surface. Since the magnetic field converges as it enters the Earth in the polar regions, the crack narrowed to about the size of California down near the upper atmosphere.

IMAGE is a NASA satellite launched March 25, 2000 to provide a global view of the space around Earth influenced by the Earth’s magnetic field. The Cluster satellites, built by the European Space Agency and launched July 16, 2000, are making a three-dimensional map of the Earth’s magnetic field.

Original Source: NASA News Release

Posted on by Fraser Cain

Boeing CEO Resigns

Image credit: Boeing

Boeing chairman and CEO Phil Condit announced his resignation this week after a flurry of scandals rocked the company over the last few weeks. His departure follows the company’s CFO, Michael Sears, who was investigated for unethical conduct in the hiring of an Air Force official this year. Boeing was also hit with ethics violations from the Pentagon after it was revealed that the company had stolen a competitor’s documents during a bid for space launch services. Condit himself isn’t under investigation, however.

announced today that its board of directors has accepted the resignation of Phil Condit, 62, as chairman and CEO. After thorough deliberations, the board decided that a new structure for the leadership of the company is needed and named Lewis E. Platt, 62, as non-executive chairman and Harry C. Stonecipher, 67, as president and CEO, effective immediately.

Both Platt and Stonecipher are experienced leaders who are knowledgeable about the company?s operations and strategy. Platt has been a member of Boeing?s board of directors for four years; he is a retired chairman of the board, president and CEO of Hewlett-Packard Company. Stonecipher retired from Boeing in 2002 after working closely with Condit for five years in several roles, including vice chairman, president and chief operating officer. Stonecipher also has served as a Boeing director for six years.

“Boeing is advancing on several of the most important programs in its history and I offered my resignation as a way to put the distractions and controversies of the past year behind us, and to place the focus on our performance,” Condit said. “I am proud of the strategies that have transformed Boeing into the world?s largest aerospace company, and I have the highest regard and respect for Lew and Harry. They each possess the knowledge, experience and leadership to take this company to the next level. I will watch the progress of Boeing with great pride.”

“The board appreciates that Phil acted with characteristic dignity and selflessness in recognizing that his resignation was for the good of the company,” said the new chairman, Lew Platt. “We accepted his decision with sadness, but also with the knowledge that changes needed to be made. The board is confident that the new leadership will bring a renewed focus on execution and performance.

“The board is in unanimous agreement that the company has been pursuing the right transformation strategy and that Boeing is in excellent financial condition,” he said.

“As the non-executive chairman, I will bring to bear the full strength and perspective of the board in guiding the company and assisting Harry in any way he requests. Harry will be responsible for executing our strategy and running every aspect of the company,” Platt said.

“Boeing has a solid foundation for the future ? strong businesses, valuable assets, and thousands of hard-working, dedicated people ? and we are all deeply grateful to Phil for his contributions and accomplishments,” Stonecipher said.

“We have the right strategy. The task before us is to execute. We need to strengthen our reputation with our customers, employees, investors and the communities in which we operate. Lew and I, and the entire board, are determined that the events of the last year no longer obscure the company?s strengths or distract us from what we need to do. Boeing is a great company with tremendous capabilities to define the future in each of our markets and deliver consistent, profitable growth,” said Stonecipher.

Lew Platt joined Hewlett-Packard in 1966 in the medical products operations and went on to manage various parts of HP?s computer business. He became an executive vice president in 1987 and retired in 1999 after serving seven years as chairman, CEO and president of HP. He was the CEO of Kendall-Jackson Wine Estates from 2000 to mid-2001.

Platt earned his bachelor?s degree in mechanical engineering from Cornell University and has a master?s degree in business administration from the Wharton School of Business, University of Pennsylvania. He serves on the boards of 7-Eleven, The Packard Foundation and the Wharton School.

Harry Stonecipher?s aerospace career spans more than 47 years from his start at General Motors? Allison Division as a lab technician to being elected vice chairman of The Boeing Company in 2001. In 1960, he joined General Electric?s aircraft engine operations, and progressed through a series of engineering and program positions, ending up running the division from 1984 to 1987.

In 1987, Stonecipher left GE to join Sundstrand and shortly thereafter became president and chief operating officer. He became president and CEO in 1989 and assumed the additional office of chairman in 1991. During his seven and a half years at Sundstrand, Stonecipher repaired the company?s seriously damaged customer relationship with the U.S. Department of Defense.

Stonecipher joined McDonnell Douglas in 1994 as president and CEO. In his short 33 months at the aerospace company he increased the financial performance of the enterprise, saw a four-fold increase in the share price, and led the merger with Boeing in 1997. At completion of the merger, Stonecipher was elected president and chief operating officer and a member of Boeing?s board.

He has a bachelor?s degree in physics from Tennessee Technological University and serves on the board of directors of PACCAR, Inc.

Original Source: Boeing News Release

Posted on by Fraser Cain

One Month Until Spirit Lands

Image credit: NASA/JPL

NASA’s twin rovers, Spirit and Opportunity, are still on track to reach the Red Planet in early January. Spirit, which launched first, is scheduled to arrive on the evening of January 3, 2004 near the centre of Gusev Crater, which might have held a lake in the past. The spacecraft will jettison its cruise stage 15 minutes before hitting the top of the Martian atmosphere, and then will slow down to only 1,500 kph before deploying its parachute. 20 seconds later its retrorockets will fire and the spacecraft will cushion its final few metres with an airbag. The rover will then spend three months exploring the Martian surface.

NASA’S robotic Mars geologist, Spirit, embodying America’s enthusiasm for exploration, must run a grueling gantlet of challenges before it can start examining the red planet. Spirit’s twin Mars Exploration Rover, Opportunity, also faces tough Martian challenges.

“The risk is real, but so is the potential reward of using these advanced rovers to improve our understanding of how planets work,” said Dr. Ed Weiler, associate administrator for space science at NASA Headquarters, Washington.

Spirit is the first of two golf-cart-sized rovers headed for Mars landings in January. The rovers will seek evidence about whether the environment in two regions might once have been capable of supporting life. Engineers at NASA’s Jet Propulsion Laboratory (JPL), Pasadena, Calif., have navigated Spirit to arrive during the evening of Jan. 3, 2004, in the Eastern time zone.

Spirit will land near the center of Gusev Crater, which may have once held a lake. Three weeks later, Opportunity will reach the Meridiani Planum, a region containing exposed deposits of a mineral that usually forms under watery conditions.

“We’ve cleared two of the big hurdles, building both spacecraft and launching them,” said JPL’s Peter Theisinger, project manager for the Mars Exploration Rover Project. “Now we’re coming up on a third, getting them safely onto the ground,” he said.

Since their launches on June 10 and July 7 respectively, each rover has been flying tucked inside a folded-up lander. The lander is wrapped in deflated airbags, cocooned within a protective aeroshell and attached to a cruise stage that provides solar panels, antennas and steering for the approximately seven month journey.

Spirit will cast off its cruise stage 15 minutes before hitting the top of the Martian atmosphere at 5,400 meters per second (12,000 miles per hour). Atmospheric friction during the next four minutes will heat part of the aeroshell to about 1,400 C (2,600 F) and slow the descent to about 430 meters per second (960 mph). Less than two minutes before landing, the spacecraft will open its parachute.

Twenty seconds later, it will jettison the bottom half of its aeroshell, exposing the lander. The top half of the shell, still riding the parachute, will lower the lander on a tether. In the final six seconds, airbags will inflate, retro rockets on the upper shell will fire, and the tether will be cut about 15 meters (49 feet) above the ground.

Several bounces and rolls could take the airbag-cushioned lander about a kilometer (0.6 mile) from where it initially lands. If any of the initial few bounces hits a big rock that’s too sharp, or if the spacecraft doesn’t complete each task at just the right point during the descent, the mission could be over. More than half of all the missions launched to Mars have failed.

JPL Director Dr. Charles Elachi said, “We have done everything we know that could be humanly done to ensure success. We have conducted more testing and external reviews for the Mars Exploration Rovers than for any previous interplanetary mission.”

Landing safely is the first step for three months of Mars exploration by each rover. Before rolling off its lander, each rover will spend a week or more unfolding itself, rising to full height, and scanning surroundings. Spirit and Opportunity each weigh about 17 times as much as the Sojourner rover of the 1997 Mars Pathfinder mission. They are big enough to roll right over obstacles nearly as tall as Sojourner.

“Think of Spirit and Opportunity as robotic field geologists,” said Dr. Steve Squyres of Cornell University, Ithaca, N.Y., principal investigator for the rovers’ identical sets of science instruments. “They look around with a stereo, color camera and with an infrared instrument that can classify rock types from a distance. They go to the rocks that seem most interesting. When they get to one, they reach out with a robotic arm that has a handful of tools, a microscope, two instruments for identifying what the rock is made of, and a grinder for getting to a fresh, unweathered surface inside the rock,” he said.

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. For information about the Mars Exploration Rover project on the Internet, visit:

http://space.mit.edu/HETE/

For Cornell University’s Web site about the science payload, visit:

http://athena.cornell.edu

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Stardust Approaches Comet Wild 2

Image credit: NASA/JPL

NASA’s Stardust spacecraft took this photograph of its target, Comet Wild 2, while it was still 25 million kilometers away. The spacecraft is on track to reach the comet on January 2, 2004 when it will pass only 300 km away and capture particles of its tail to return to Earth for analysis – the best photographs are still to come. Mission planners will use these early images to help fine-tune Startdust’s trajectory to give it the closest possible approach to Wild 2’s centre.

Forty-nine days before its historic rendezvous with a comet, NASA’s Stardust spacecraft successfully photographed its quarry, comet Wild 2 (pronounced Vilt-2), from 25 million kilometers (15.5 million miles) away. The image, the first of many comet portraits it will take over the next four weeks, will aid Stardust?s navigators and scientists as they plot their final trajectory toward a Jan. 2, 2004 flyby and collection of samples from Wild 2.

?Christmas came early this year,? said Project Manager Tom Duxbury at NASA?s Jet Propulsion Laboratory, Pasadena, Calif. ?Our job is to aim a 5 meter (16 foot) long spacecraft at a 5.4 kilometer (3.3 mile) wide comet that is closing on it at six times the speed of a bullet. We plan to ?miss the comet? by all of 300 kilometers (188 miles), and all this will be happening 389 million kilometers (242 million miles) away from home. By finding the comet as early and as far away as we did, the complexity of our operations leading up to encounter just dropped drastically.?

The ball of dirty ice and rock, about as big as three Brooklyn Bridges laid end-to-end, was detected on November 13 by the spacecraft?s optical navigation camera on the very first attempt. The set of images was stored in Stardust?s onboard computer and downloaded the next day where mission navigator Dr. Shyam Bhaskaran processed them and noticed a white blob of light bisecting the base of a triangle made by three stars Stardust uses for deep space navigation.

?When I first looked at the picture I didn?t believe it,? said Bhaskaran. ?We were not expecting to observe the comet for at least another two weeks. But there it was, very close to where we thought it would be.?

The Wild 2 sighting was verified on November 18 using the second set of optical navigation images downloaded from Stardust. To make this detection, the spacecraft?s camera saw stars as dim as 11th visual magnitude, more than 1,500 times dimmer than a human can see on a clear night.

The early detection of Wild 2 provides mission navigators critical information on the comet?s position and orbital path. Future optical navigation images will allow them to do more fine-tuning. In turn, these new orbital plots will be used to plan the spacecraft?s approach trajectory correction maneuver. Stardust?s first such maneuver is planned for December 3.

Unlike other orbiting bodies, the paths of comets cannot be precisely predicted because their orbits about the Sun are not solely determined by gravity. The escape of gas, dust and rock from comets provides a “rocket effect” that causes them to stray from a predictable orbital path. The actual orbital path cannot be precisely determined from Earth-based telescopes because the comet is shrouded in a cloud of escaping gas and dust. What is seen from Earth is not the actual 5.4 kilometer (3.3 mile) wide body composed of rock and ice, but the cloud of debris and gas that envelops it.

?With these images we anticipate we will flyby comet Wild 2 at an altitude of 300 kilometers, give or take about 16 kilometers,? added Bhaskaran. ?Without them, we wouldn?t be able to safely get any closer to the comet than several thousand kilometers.?

Stardust will return to Earth in Jan. 2006 to make a soft landing at the U.S. Air Force Utah Test and Training Range. Its sample return capsule, holding microscopic particles of comet and interstellar dust, will be taken to the planetary material curatorial facility at NASA’s Johnson Space Center, Houston, where the samples will be carefully stored and examined.

Stardust?s cometary and interstellar dust samples will help provide answers to fundamental questions about the origins of the solar system. More information on the Stardust mission is available at http://stardust.jpl.nasa.gov .

Stardust, a part of NASA’s Discovery Program of low-cost, highly focused science missions, was built by Lockheed Martin Astronautics and Operations, Denver, Colo., and is managed by JPL for NASA’s Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology in Pasadena. The principal investigator is astronomy professor Donald E. Brownlee of the University of Washington in Seattle.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Atlas Launches Classified Payload

Image credit: ILS

An Atlas IIAS rocket lifted off from Vandenberg Air Force Base, California this morning at 1004 UTC (5:04 am EST), carrying a classified payload for the National Reconnaissance Office. Although no details about the payload were disclosed, industry experts believe it was probably contained two or three Naval Ocean Surveillance System (NOSS) spacecraft, which track and identify boats on the ocean. This was the 67th consecutive successful Atlas flight.

An Atlas IIAS rocket successfully lifted off today at 2:04 a.m. PST (10:04 GMT) from this West Coast launch site, releasing a national security payload into transfer orbit 74 minutes later.

The launch was provided by McLean, Va.-based International Launch Services (ILS), from Vandenberg Space Launch Complex 3E, for the U.S. Air Force and the National Reconnaissance Office (NRO). Designated AC-164, this was the fourth Atlas mission this year, and the 67th consecutive successful Atlas flight. It also was ILS? fifth mission of 2003.

?ILS is honored to have a major role in enhancing our nation?s security, having now launched five NRO payloads,? said ILS President Mark Albrecht. ?ILS and Lockheed Martin share a long and valued partnership with the Office of Space Launch, and we take great pride in providing mission success.?

Albrecht added: ?Now we?re working toward NRO launches in 2004, 2005 and beyond, on Atlas III and Atlas V boosters from both Cape Canaveral, Fla., and from Vandenberg. With Atlas V capability at both coasts, we look forward to meeting NRO mission requirements well into the next decade.?

Lockheed Martin Corp. builds the Atlas family of rockets. Today?s vehicle, the Atlas IIAS, can lift 8,200 pounds to geosynchronous transfer orbit. The Atlas III can lift up to 9,920 pounds, and the current -production Atlas V is available in a range of configurations to lift payloads up to 19,000 pounds. Today?s mission was the final West Coast flight of the Atlas IIAS vehicle. Lockheed Martin soon will begin refurbishing Complex 3E, to accommodate Atlas V operations starting in 2005.

The Atlas V family is designed both for ILS commercial missions and to meet the U.S. Air Force requirements for the Evolved Expendable Launch Vehicle (EELV). The Atlas V vehicle has flown three commercial missions, all successfully. The first U.S. government Atlas V mission is set for 2005 with the Wideband Gapfiller Satellite #2 for the Air Force.

ILS is a joint venture of Lockheed Martin Corp. that markets and manages government and commercial missions on the Atlas rocket to customers worldwide. The company is headquartered near Washington, D.C.

The Atlas rockets and their Centaur upper stages are built by Lockheed Martin Space Systems Company in Denver, Colo.; Harlingen, Texas; and San Diego, Calif.

Original Source: ILS News Release

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Chinese Moon Shot by 2020

According to a report by the Associated Press, the Chinese are planning to put humans on the Moon by 2020. If everything goes as planned, the Chinese will probably launch a probe to orbit the Moon in 2007, and land a spacecraft there in 2010. Since their first launch of a human in October 2003, China has been much more forthcoming about their spaceflight plans. Earlier this month China said that they will probably launch their next Shenzhou flight within two years, potentially carrying two humans into space.

Posted on by Fraser Cain

Japanese Rocket Destroyed Shortly After Launch

Image credit: JAXA

The Japanese space program suffered a setback on Saturday when a booster failed to detach from an H2-A rocket. Operators forced the rocket to self destruct, as it wouldn’t be able to reach its intended orbit with the additional weight of the booster. The rocket was carrying two spy satellites which were intended to keep an eye on North Korea’s rocket program. Prior to Saturday’s failure, the H2-A rocket had launched five consecutive times safely, but insurance companies will probably require six safe launches before covering commercial launches.

The Japan Aerospace Exploration Agency (JAXA) launched the H-IIA Launch Vehicle No 6 (H-IIA F6) with the information gathering satellite #2 (IGS) onboard from the Tanegashima Space Center at 13:33 on November 29, 2003 (Japan Standard Time). However, the vehicle failed to jettison one of its two Solid Rocket Boosters (SRB-As). H-IIA F6 was consequently destroyed by a destruction command from the ground at 13:43:53 as the vehicle did not gain enough height and speed due to the failure.

JAXA has established an accident investigation team led by President Yamanouchi and is investigating the cause of the accident. JAXA will provide additional information when it becomes available.

Posted on by Fraser Cain

Evidence for Planets Around Vega

Image credit: PPARC

Astronomers from the Particle Physics and Astronomy Research Council believe they’ve discovered a planetary system around Vega, one of the brightest stars in the sky. Not only that, the star system seems remarkably similar to our own Solar System. So far, they’ve found evidence for a Neptune-sized planet in the same orbit as our own Neptune. This means there could be smaller, rocky planets closer in to the star.

Astronomers at the Particle Physics and Astronomy Research Councils UK Astronomy Technology Centre (ATC) at the Royal Observatory, Edinburgh have produced compelling new evidence that Vega, one of the brightest stars in the sky, has a planetary system around it which is more like our own Solar System than any other so far discovered.

All of the hundred or so planets that have been discovered around other stars have been very large gaseous (Jupiter-like) planets orbiting close to their star. This is very unlike our own Solar System. New computer modelling techniques have shown that observations of the structure of a faint dust disk around Vega can be best explained by a Neptune-like planet orbiting at a similar distance to Neptune in our own solar system and having similar mass. The wide orbit of the Neptune-like planet means that there is plenty of room inside it for small rocky planets similar to the Earth the Holy Grail for astronomers wanting to know whether we are alone in the Universe.

The modelling, which is described today (1 December 2003) in The Astrophysical Journal, is based on observations taken with the world’s most sensitive submillimetre camera, SCUBA. The camera, built at the ATC, is operated on the James Clerk Maxwell Telescope in Hawaii. The SCUBA image shows a disk of very cold dust (-180 degrees centigrade) in orbit around the star.

The irregular shape of the disk is the clue that it is likely to contain planets explains astronomer Mark Wyatt, the author of the paper. Although we cant directly observe the planets, they have created clumps in the disk of dust around the star.

The modelling suggests that the Neptune-like planet actually formed much closer to the star than its current position. As it moved out to its current wide orbit over about 56 million years, many comets were swept out with it, causing the dust disk to be clumpy.

Exactly the same process is thought to have happened in our Solar System, said Wyatt, Neptune was pushed away from the Sun because of the presence of Jupiter orbiting inside it. So it appears that as well as having a Neptune-like planet, Vega may also have a more massive Jupiter-like planet in a smaller orbit.

The model can be tested in two ways as Wayne Holland, who made the original observations, explains The model predicts that the clumps in the disk will rotate around the star once every three hundred years. If we take more observations after a gap of a few years we should see the movement of the clumps. Also the model predicts the finer detail of the disks clumpiness which can be confirmed using the next generation of telescopes and cameras.

Paradoxically the star barely appears in the SCUBA image because it is far too hot to be seen with this kind of detector. Vega is, however, easily seen with the naked eye. It is the third brightest star visible from Northern latitudes and is bluish-white in colour. Tonight you can see it in the west at around 7pm.

Facts about Vega
* Vega is the fifth brightest star in the sky and the third brightest visible in the Northern hemisphere.
* It is 25 light years away from the Sun (1AU is the distance between the Earth and Sun).
* It has a diameter three times bigger than the Sun.
* It is 58 times brighter than the Sun.
* Together with Deneb and Altair, Vega forms the summer triangle.
* Vega is the brightest star in the constellation Lyra, the Harp. The lyre, or harp, is supposed to have been invented by the Greek God Hermes who gave it to his half-brother Apollo. Apollo then gave it to his son Orpheus, the musician of the Argonaughts.
* Vega was the first star ever to be photographed. During the night of July 16-17 1850 the historic picture was taken at Harvard Observatory using a 15 inch refractor telescope during a 100 second exposure.

Original Source: PPARC News Release

Posted on by Fraser Cain

Neptune Emptied the Kuiper Belts

Image credit: NASA

Researchers from the Southwest Research Institute believe they have a theory that could help explain why there are so few objects in the Kuiper belt – a band of objects outside the orbit of Neptune. According to theories of how planetary systems form, there should be 100 times more material in the Kuiper belt than astronomers have observed. The researchers believe that the gas giants, including Neptune, formed closer to the Sun, and have slowly drifted further out over time. As Neptune migrated out, it could have pushed the Kuiper objects out of the solar system.

A new study by researchers at Southwest Research Institute (SwRI) and the Observatoire de la C?te d’Azur provides an explanation for one of the more mysterious aspects of the population of objects beyond Neptune. In doing so, it provides a unique glimpse into the proto-planetary disk from which the Solar System’s planets formed. Results will be published in the November 27 issue of Nature.

The Kuiper belt is a region of the Solar System that extends outward from Neptune’s orbit, containing billions of icy objects from kilometers to thousands of kilometers across. It was discovered in 1992 and, since that time nearly 1,000 objects have been cataloged. Some of these objects are very large – the largest having a diameter of more than 1,000 kilometers.

As astronomers have studied this structure, a mystery has unfolded. Like most of the planets in the Solar System, the large Kuiper belt objects are believed to have been formed from smaller objects that stuck together when they collided. For this process to have worked in the distant regions beyond Neptune, the Kuiper belt would have to contain more than 10 times the amount of material than is in the Earth. However, telescopic surveys of this region show that it currently contains roughly one-tenth the mass of the Earth, or less.

To solve the puzzle, researchers have been searching for several years for a way to remove more than 99 percent of the Kuiper belt’s material. However, Dr. Harold Levison (SwRI) and Dr. Alessandro Morbidelli (Observatoire de la C?te d’Azur of Nice, France) describe in their article, “Forming the Kuiper Belt by the Outerward Transport of Objects During Neptune’s Migration,” that the Kuiper belt may not have lost much mass at all.

“The mass depletion problem has been sticking in our throat for some time,” says Levison, a staff scientist in the SwRI Space Studies Department. “It looks like we may finally have a possible answer.”

Levison and Morbidelli argue that the proto-planetary disk from which the planets, asteroids and comets all formed had a heretofore unanticipated edge at the current location of Neptune, which is at 30 astronomical units (AU, the average distance between the Sun and Earth), and that the region now occupied by the Kuiper belt was empty. All the Kuiper belt objects we see beyond Neptune formed much closer to the Sun and were transported outward during the final stages of planet formation.

Researchers have known for 20 years that the orbits of the giant planets moved around as they formed. In particular, Uranus and Neptune formed closer to the Sun and migrated outward. Levison and Morbidelli show that Neptune could have pushed all the observed Kuiper belt objects outward as it migrated.

“We really didn’t solve the mass depletion problem, we circumvented it,” says Levison. “According to our work, the void beyond Neptune was probably devoid of objects.”

However, in this model, the region interior to 30 AU contained enough material for the Kuiper belt objects to form. The mechanisms employed by Neptune to push out the Kuiper belt only affected a small fraction of the objects. These became the objects seen by astronomers; the rest were scattered out of the Solar System by Neptune. This new theory explains many of the observable features of the outer Solar System, including the characteristics of the orbits of the Kuiper belt objects and the location of Neptune.

“One of the puzzling aspects of Neptune’s migration is why it stopped where it did,” says Morbidelli. “Our new model explains this as well. Neptune migrated until it hit the edge of the proto-planetary disk, at which point it abruptly stopped.”

NASA, the National Science Foundation and the Centre National de la Recherche Scientifique in Paris funded this research.

Original Source: SwRI News Release

Posted on by Fraser Cain

Mars Odyssey Instrument Fails

Image credit: NASA/JPL

During a recent solar storm, an instrument on board NASA’s Mars Odyssey spacecraft failed, and so far, operators haven’t been able to get it working again. The Martian Radiation Environment (MARIE) was designed to measure the radiation in the Martian space environment, which will help mission planners understand what kinds of risks humans might face if they traveled to the Red Planet. Operators will continue their attempts to get the instrument working for a few weeks before writing it off.

The martian radiation environment experiment on NASA?s 2001 Mars Odyssey orbiter has collected data continuously from the start of the Odyssey mapping mission in March 2002 until late last month. The instrument has successfully monitored space radiation to evaluate the risks to future Mars-bound astronauts. Its measurements are the first of their kind to be obtained during an interplanetary cruise and in orbit around another planet.

On Oct. 28, 2003, during a period of intense solar activity, the instrument stopped working properly. Controllers? efforts to restore the instrument to normal operations have not been successful. These efforts will continue for the next several weeks or months.

The martian radiation environment experiment detects energetic charged particles, including galactic cosmic rays and particles emitted by the Sun in coronal mass ejections. The dose equivalent from galactic cosmic rays as measured by the instrument agrees well with predictions based on modeling. Validation of radiation models is a crucial step in predicting radiation-related health risks for crews of future missions.

“Even if the instrument provides no additional data in the future, it has been a great success at characterizing the radiation environment that a crewed mission to Mars would need to anticipate,” said Dr. Jeffrey Plaut, project scientist for Mars Odyssey at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.

JPL manages the Mars Odyssey and Global Surveyor missions for NASA’s Office of Space Science, Washington, D.C. Investigators at Arizona State University, Tempe; University of Arizona, Tucson; NASA’s Johnson Space Center, Houston; the Russian Aviation and Space Agency, Moscow; and Los Alamos National Laboratory, Los Alamos, N.M., built and operate Odyssey science instruments. Information about NASA’s Mars exploration program is available on the Internet at: http://mars.jpl.nasa.gov.

Original Source: NASA/JPL News Release