Posted on by Fraser Cain

Matter is Incinerated When it Falls into a Black Hole

Image credit: ESA
Contrary to established scientific thinking, you’d be roasted and not “spaghettified” if you stumbled into a supermassive black hole. New research being presented at the Institute of Physics conference Physics 2005 in Warwick will take a new look at the diet of the universe’s most intriguing object, black holes.

Black holes stand at the very edge of scientific theory. Most scientists believe they exist, although many of their theories break down under the extreme conditions within. But Professor Andrew Hamilton of the University of Colorado says he knows what you would find inside, and challenges the traditional idea that gravity would cause you death by “spaghettification”.

Most people have heard of the event horizon of a black hole, as the point of no return. But astronomically realistic black holes are more complex and should have two horizons, an outer and an inner. In the bizarre physics of black holes, time and space are exchanged when you cross an event horizon, but at a second horizon they would switch back again.

Traveling into a black hole, you would therefore pass through a strange region where space is falling inward faster than light, before finally entering a zone of normal space at the core. It’s this core of normal space which Professor Hamilton has been working on.

A so-called singularity sits at the centre of the core, swallowing up matter. But according to Professor Hamilton, the strange laws of general relativity temper its appetite. If the singularity ate too quickly, it would become gravitationally repulsive, so instead, matter piles up in a hot, dense plasma filling the core of the black hole and siphoning gradually into the singularity.

Depending on the size of the black hole, this plasma could be the cause of a space traveller’s demise. Most books will tell you that under the extreme gravitational conditions of a black hole, your feet would experience gravity more strongly than your head, and your body would be stretched out like spaghetti.

For a small black hole with the mass of several suns, this should still be true. But for a supermassive black hole weighing millions or billions of suns, explains Professor Hamilton, the tidal forces which cause spaghettification are relatively weak. You would instead be roasted by the heat of the plasma.

Professor Andrew Hamilton is Professor of Astrophysics at the Department of Astrophysical and Planetary Sciences, University of Colorado.

Original Source: Institute of Physics News Release

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Michael Griffin Takes the Helm at NASA

Michael Griffin is returning to NASA as the Agency’s 11th Administrator.

He reported to work at NASA Headquarters in Washington on Thursday, April 14, the same day the Expedition 11 crew launched to the International Space Station.

“I have great confidence in the team that will carry out our nation’s exciting, outward-focused, destination-oriented program,” said Griffin. “I share with the agency a great sense of privilege that we have been given the wonderful opportunity to extend humanity’s reach throughout the solar system.”

Administrator Griffin, who served as NASA’s Chief Engineer earlier in his career, takes the helm of the Agency as it’s charting a new course. The Space Shuttle fleet is poised to Return to Flight, the first step in fulfilling the Vision for Space Exploration — a bold plan to return humans to the Moon, journey to Mars and beyond.

In his first address to NASA employees, Griffin said he would focus immediately on Return to Flight efforts, and noted that the Agency has much on its plate right now. “It’s going to be difficult, it’s going to be hectic, but we will do it together,” he said.

He also told employees that he saw “nothing but cheers” in the public reaction to the Vision. “People want a space program that goes somewhere and does something,” he said.

Griffin was nominated by President George W. Bush on March 14, 2005, and confirmed by the United States Senate on April 13, 2005. At his confirmation hearing on April 12, he made clear that the “strategic vision for the U.S. manned space program is of exploration beyond low Earth orbit.”

In his statement to the committee, Griffin said, “It is a daring move at any time for a national leader to call for the bold exploration of unknown worlds, a major effort at the very limit of the technical state of the art,” adding later, “in the twenty-first century and beyond, for America to continue to be preeminent among nations, it is necessary for us also to be the preeminent spacefaring nation.”

A holder of five master’s degrees and a Ph.D., Griffin also made clear that, despite limited resources, “NASA can do more than one thing at a time.”

“My conclusion is that we as a nation can clearly afford well-executed, vigorous programs in both robotic and human space exploration as well as in aeronautics. We know this. We did it,” he said, referring back to the Agency’s accomplishments during the Apollo era.

He closed his statement with a call for exploration: “I believe that, if money is to be spent on space, there is little doubt that the huge majority of Americans would prefer to spend it on an exciting, outward-focused, destination-oriented program. And that is what the President’s Vision for Space Exploration is about.”

Prior to his appointment, Griffin was serving as Space Department Head at Johns Hopkins University Applied Physics Laboratory. Prior to that, he was President and Chief Operating Officer of In-Q-Tel, Inc. He also served in several positions within Orbital Sciences Corporation, including Chief Executive Officer of Magellan Systems, Inc.

Earlier in his career, Griffin served as chief engineer and associate administrator for exploration at NASA Headquarters and also worked at NASA’s Jet Propulsion Laboratory. He also served as Deputy for Technology at the Strategic Defense Initiative Organization.

Griffin received a bachelor’s degree in Physics from Johns Hopkins University; a master’s degree in Aerospace Science from Catholic University of America; a Ph.D. in Aerospace Engineering from the University of Maryland; a master’s degree in Electrical Engineering from the University of Southern California; a master’s degree in Applied Physics from Johns Hopkins University; a master’s degree in Business Administration from Loyola College; and a master’s degree in Civil Engineering from George Washington University.

Original Source: NASA News Release

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Expedition 11 Blasts Off for the Station

The Expedition 11 crew — Cosmonaut Sergei Krikalev and Astronaut John Phillips — launched from the Baikonur Cosmodrome in Kazakhstan at 8:46 p.m. EDT Thursday, right on schedule.

Their Soyuz TMA capsule reached orbit a little less than nine minutes after liftoff. Russian flight controllers reported the spacecraft’s solar arrays had deployed as scheduled, and that all appeared normal.

With this 11th crew of the International Space Station is European Space Agency Astronaut Roberto Vittori of Italy. Their Soyuz is scheduled to dock with the Space Station at 10:19 p.m. EDT April 16.

Expedition 11’s Krikalev and Phillips will spend about six months aboard the Space Station. Vittori will spend almost eight days on the Station conducting scientific experiments, and return to Earth with the Expedition 10 crew.

That crew, Commander Leroy Chiao and Cosmonaut Salizhan Sharipov, has been on the station since October. They will leave the station April 24 in the Soyuz that brought them to the orbiting laboratory. Their landing is scheduled for 6:09 p.m. EDT that day in Kazakhstan.

Highlights of the new crew’s mission include welcoming the crew of the Space Shuttle Discovery on its STS-114 mission, the first Shuttle flight since the Columbia accident. Discovery crewmembers will conduct three spacewalks at the Station, deliver several tons of equipment and supplies and return to Earth with equipment and scientific experiments and trash from the Station.

Krikalev, 46, and Phillips, 54, will receive extensive handover briefings from their Expedition 10 predecessors, and will get training on the Station’s robotic Canadarm2.

They also may see the addition of a third crewmember to the Station this summer brought to the station by Atlantis on the STS-121 mission. Plans call for them to do two spacewalks, the first in August from the U.S airlock Quest in U.S. spacesuits, and the second, in September, in Russian spacesuits from the Pirs airlock. The spacewalkers will continue outfitting the station’s exterior and work with scientific experiments.

Krikalev and Phillips also will welcome the arrival of two Progress unpiloted supply vehicles. ISS Progress 18 is scheduled to reach the Station in June and ISS Progress 19 should be launched near the end of August.

In August, Krikalev, who also is Soyuz commander, and Phillips, who also will have the title of NASA ISS science officer, will move their Soyuz spacecraft from the Pirs docking compartment to the Zarya docking port. That will permit use of the Pirs airlock for spacewalk activity.

Krikalev is a veteran of five previous spaceflights, including two missions to the Russian space station Mir and two Shuttle flights. He was a member of the first Station Crew, serving aboard a much smaller ISS from Nov. 2, 2000, to March 18, 2001. He has spent a year, 5 months and 10 days in space. This flight should see him become the world’s most experienced space traveler.

Born in Leningrad (now St. Petersburg), Russia, he graduated from what is now St. Petersburg Technical University in 1981 and then joined NPO Energia, the Russian organization responsible for human spaceflight. He was selected as a cosmonaut in 1985.

Record or not, just being in space isn’t what’s important, Krikalev says. “The job itself is very interesting for me, being there and being able to look back on Earth, to do something challenging.” He said he probably hasn’t paid enough attention to that record.

Philips was born in Fort Belvoir, Va., and considers Scottsdale, Ariz., his home. He graduated from the Naval Academy in 1972 and became a Naval aviator. After leaving the Navy in 1982, he earned a masters and doctorate in geophysics and space physics from the University of California in 1984 and 1987. He did postdoctoral work at the Los Alamos Scientific Laboratory in New Mexico.

He was selected as an astronaut in 1996. He was a member of the STS-100 crew of Endeavour in 2001. On that mission he coordinated two spacewalks at the Station to install Canadarm2.

Phillips has wanted to return to the Station ever since. “It was a wonderful place to be,” he said. “The crew was doing a great job; they were having a good time.” He wanted to stay longer then. Now he’ll have about six months there.

Krikalev and Phillips are the Station’s fifth two-person crew. After the Columbia accident on Feb. 1, 2003, the ISS Program and the international partners determined that because of limitations on supplies the Station would be occupied by two crewmembers instead of three until Shuttle flights resume.

The 11th crew will continue science activities, initially with facilities and samples already on the station, but later with experiments scheduled to arrive at the station aboard Discovery.

The science team at the Payload Operations Center at the Marshall Space Flight Center in Huntsville, Ala., will continue to operate some experiments without crew input and other experiments are designed to function autonomously.

Krikalev and Phillips are scheduled to spend about 180 days on the Station, returning to Earth in October, a little over a week after the arrival of their Expedition 12 successors.

Original Source: NASA News Release

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Enceladus Above Saturn’s Rings

Saturn’s bright moon Enceladus hovers here, in front of a rings darkened by Saturn’s shadow. Enceladus is 505 kilometers (314 miles) across.

This view is from less than one degree beneath the ring plane. If seen from directly beneath the rings, the planet’s giant shadow would appear as an elongated half-ellipse; the acute viewing angle makes the shadow look more like a strip here. (See The Greatest Saturn Portrait…Yet, for a different viewing angle). The dark shadow first takes a bite out of the rings at the right, where the distant, outermost ring material appears to taper and fade.

Ring features visible in this image from the outer ring edge inward include: the A ring, the Cassini Division and the B ring. The C ring is the darker region that dominates the rings here. The two gaps visible near the center and below the left of the center are the Titan Gap, about 77,800 kilometers (48,300 miles) from Saturn, and an unnamed gap about 75,800 kilometers (47,100 miles) from the planet.

The image was taken in visible light with the Cassini spacecraft narrow-angle camera on March 7, 2005, at a distance of approximately 1.1 million kilometers (650,000 miles) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 30 degrees. The pixel scale is 6 kilometers (4 miles) per pixel.

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 mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . For additional images visit the Cassini imaging team homepage http://ciclops.org .

Original Source: NASA/JPL/SSI News Release

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Podcasts: Best Spot for a Lunar Base

In case you missed the news, NASA is headed back to the Moon in the next decade. A permanent lunar base could be down the road, so scientists are starting to consider where we should build. Ben Bussey, with Johns Hopkins University Applied Physics Laboratory in Maryland likes the Moon’s North Pole. It’s got everything you might need for a long-term stay: permanent sunlight, relatively stable temperatures, and lots of lunar soil. And as an added bonus, there might be plenty of frozen water hiding in lunar craters.
Continue reading “Podcasts: Best Spot for a Lunar Base”

Posted on by Fraser Cain

Audio: Best Spot for a Lunar Base

In case you missed the news, NASA is headed back to the Moon in the next decade. A permanent lunar base could be down the road, so scientists are starting to consider where we should build. Ben Bussey, with Johns Hopkins University Applied Physics Laboratory in Maryland likes the Moon’s North Pole. It’s got everything you might need for a long-term stay: permanent sunlight, relatively stable temperatures, and lots of lunar soil. And as an added bonus, there might be plenty of frozen water hiding in lunar craters.

Listen to the interview: North Pole Lunar Base (2.9 mb)

Or subscribe to the Podcast: universetoday.com/audio.xml

Posted on by Fraser Cain

Strange Extrasolar Planet Orbits Explained

Image credit: NWU
The peculiar orbits of three planets looping around a faraway star can be explained only if an unseen fourth planet blundered through and knocked them out of their circular orbits, according to a new study by researchers at the University of California, Berkeley, and Northwestern University.

The conclusion is based on computer extrapolations from 13 years of observations of planet motions around the star Upsilon Andromedae. It suggests that the non-circular and often highly elliptical orbits of many of the extrasolar planets discovered to date may be the result of planets scattering off one another. In such a scenario, the perturbing planet could be shot out of the system entirely or could be kicked into a far-off orbit, leaving the inner planets with eccentric orbits.

“This is probably one of the two or three extrasolar systems that have the best observations and tightest constraints, and it tells a unique story,” said Eric Ford, a Miller postdoctoral fellow at UC Berkeley. “Our explanation is that the outer planet’s original orbit was circular, but it got this sudden kick that permanently changed its orbit to being highly eccentric. To provide that kick, we’ve hypothesized that there was an additional planet that we don’t see now. We believe we now understand how this system works.”

If such a planet had caromed through our solar system early in its history, the researchers noted, the inner planets might not now have such nicely circular orbits, and, based on current assumptions about the origins of life, Earth’s climate might have fluctuated too much for life to have arisen.

“While the planets in our solar system remain stable for billions of years, that wasn’t the case for the planets orbiting Upsilon Andromedae,” Ford said. “While those planets might have formed similarly to Jupiter and Saturn, their current orbits were sculpted by a late phase of chaotic and violent interactions.”

According to Ford’s colleague, Frederic A. Rasio, associate professor of physics and astronomy at Northwestern, “Our results show that a simple mechanism, often called ‘planet-planet scattering’ – a sort of slingshot effect due to the sudden gravitational pull between two planets when they come very near each other – must be responsible for the highly eccentric orbits observed in the Upsilon Andromedae system. We believe planet-planet scattering occurred frequently in extrasolar planetary systems, not just this one, resulting from strong instabilities. So, while planetary systems around other stars may be common, the kinds of systems that could support life, which, like our solar system, presumably must remain stable over very long time scales, may not be so common.”

The computer simulations are reported in the April 14 issue of the journal Nature by Ford, Rasio and Verene Lystad, an undergraduate student majoring in physics at Northwestern. Ford was a student of Rasio’s at the Massachusetts Institute of Technology before pursuing graduate studies at Princeton University and arriving at UC Berkeley in 2004.

The planetary system around Upsilon Andromedae is one of the most studied of the 160-some systems with planets discovered so far outside our own solar system. The inner planet, a “hot Jupiter” so close to the star that its orbit is only a few days, was discovered in 1996 by UC Berkeley’s Geoff Marcy and his planet-hunting team. The two outer planets, with elongated orbits that perturb each other strongly, were discovered in 1999. These three, huge, Jupiter-like planets around Upsilon Andromedae comprised the first extrasolar multi-planet system discovered by Doppler spectroscopy.

Because of the unusual nature of the planetary orbits around Upsilon Andromedae, Marcy and his team have studied it intensely, making nearly 500 observations – 10 times more than for most other extrasolar planets that have been found. These observations, the wobbles in the star’s motion induced by the orbiting planets, allow a very precise charting of the planets’ motions around the star.

“The observations are so precise that we can watch and predict what will happen for tens of thousands of years in the future,” Ford said.

Today, while the innermost planet huddles close to the star, the two outer planets orbit in egg-shaped orbits. Computer simulations of past and future orbital changes showed, however, that the outer planets are engaged in a repetitive dance that, once every 7,000 years, brings the orbit of the middle planet to a circle.

“That property of returning to a very circular orbit is quite remarkable and generally doesn’t happen,” Ford said. “The natural explanation is that they were once both in circular orbits, and one got a big kick that caused it to become eccentric. Then, the subsequent evolution caused the other planet to grow its eccentricity, but because of the conservation of energy and angular momentum, it returns periodically to a very nearly circular orbit.”

Previously, astronomers had proposed two possible scenarios for the formation of Upsilon Andromedae’s planet system, but the observational data was not yet sufficient to distinguish the two models. Another astronomer, Renu Malhotra at the University of Arizona, had previously suggested that planet-planet scattering might have excited the eccentricities in Upsilon Andromedae. But an alternative explanation claimed that interactions among the planets and a gas disk surrounding the star could also have produced such eccentric orbits. By combining additional observational data with new computer models, Ford and his colleagues were able to show that interactions with a gas disk would not have produced the observed orbits, but that interactions with another planet would naturally produce them.

“The key distinguishing feature between those theories was that interactions with an outer disk would cause the orbits to change very slowly, and a strong interaction with a passing planet would cause the orbits to change very quickly compared to the 7,000-year time scale for the orbits to evolve,” Ford said. “Because the two hypotheses make different predictions for the evolution of the system, we can constrain the history of the system based on the current planetary orbits.”

Ford said that as the planets formed inside a disk of gas and dust, the drag on the planets would have kept their orbits circular. Once the dust and gas dissipated, however, only an interaction with a passing planet could have created the particular orbits of the two outer planets observed today. Perhaps, he noted, the perturbing planet was knocked into the inner planets by interactions with other planets far from the central star.

However it started, the resulting chaotic interactions would have created a very eccentric orbit for the third planet, which then also gradually perturbed the second planet’s orbit. Because the outer planet dominates the system, over time it perturbed the middle planet’s orbit enough to deform it slowly into an eccentric orbit as well, which is what is seen today, although every 7,000 years or so, the middle planet returns gradually to a circular orbit.

“This is what makes the system so peculiar,” said Rasio. “Ordinarily, the gravitational coupling between two elliptic orbits would never make one go back to a nearly perfect circle. A circle is very special.”

“Originally the main objective of our research was to simulate the Upsilon Andromedae planetary system, essentially in order to determine whether the outer two planets lie in the same plane like the planets in the solar system do,” said Lystad, who started working with Rasio when she was a sophomore and did many of the computer integrations as part of her senior thesis. “We were surprised to find that, for many of our simulations, it was difficult to tell whether the planets were in the same plane due to the fact that the middle planet’s orbit periodically became so very nearly circular. Once we noticed this strange behavior was present in all of our simulations, we recognized it as an earmark of a system that had undergone planet-planet scattering. We realized there was something much more interesting going on than anyone had found before.”

Understanding what happened during the formation and evolution of Upsilon Andromedae and other extrasolar planetary systems has major implications for our own solar system.

“Once you realize that most of the known extrasolar planets have highly eccentric orbits (like the planets in Upsilon Andromedae), you begin to wonder if there might be something special about our solar system,” Ford said. “Could violent planet-planet scattering be so common that few planetary systems remain calm and habitable? Fortunately, astronomers – led by Geoff Marcy, a professor of astronomy at UC Berkeley – are diligently making the observations that will eventually answer this exciting question.”

The research was supported by the National Science Foundation and UC Berkeley’s Miller Institute for Basic Research.

Original Source: Berkeley News Release

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Next Up, Mars Science Laboratory

Even before the Mars Science Lander (MSL) touches down descending from its hovering mother ship like a baby spider from an egg case the first of a slew of cameras will have started recording, capturing and storing high-resolution video of the landing area.

The MSL landing will represent a first, says Frank Palluconi, MSL project scientist. After entering the Mars atmosphere like Viking and MER but with a potential landing zone about one fourth the size he says, MSL will show its stuff. “It completes the descent down to the ten-meter [33-foot] level, or so, where the descent vehicle hovers, and it lowers the rover on a tether down to the surface. By that time, the rover has erected its wheels, so it lands on its mobility system. And then the tether is cut and the descent stage flies away and is no longer used. It crashes.”

In addition to the obvious advantages of such a soft landing, hovering and the tether drop are possible to model mathematically, unlike the airbag landing the MER vehicles used. Tethered descent is also scalable, Palluconi says, whereas the much smaller MERs were pushing the envelope of the airbag system’s capability.

Eyes on Mars
Shooting will begin as soon as the heat shield drops from the MSL descent stage. The Mars Descent Imager will take video in megapixel resolution, comparable to modern consumer digital video cameras. Aimed straight down, this camera will provide a spider’s eye view of the landing area a very wide angle at first and continue shooting until the rover touches down on Mars.

Landing videos will be transmitted to Earth by the rover when it becomes fully functional. This visual information, showing the landing area and its surroundings in fine detail, along with the fact that the rover will land on its wheels no tricky navigation off of a landing vehicle needed will allow project scientists to begin working the rover much sooner.

Once the rover’s mast rises and all systems are go, the real work will begin. As with MER, a mast-mounted, two-eyed camera system will feature prominently. The MastCam, like the descent imager and an arm-mounted close-up camera, is being designed and built by Malin Space Science Systems in San Diego, CA. All three rely on similar full-color, high-resolution subsystems. MastCam takes the basic setup found on the MERs twin cameras that will allow scientists to assemble 3D images and refines it considerably. MastCam has twin 10x optical zoom lenses, the same power as found in high-end consumer digital cameras on Earth. This will allow the camera to take not only wide-angle panoramas but also zoom in and focus on fist-sized rocks a kilometer (0.6 miles) away.

MastCam also shoots high definition video, a first for Mars. Both stills and video will be captured in full color, just like with earthbound digital cameras. In addition, MastCam will use a variety of specialized filters. Several members of the Malin Space Science Systems scientific team contributed to the various camera designs, including director James Cameron (Titanic, The Abyss, Aliens), a coinvestigator on the MastCam science team.

Photograph, Vaporize, Analyze
The MSL mast will also hold a unique hybrid optical instrument, never before flown to Mars. Called the ChemCam, this telescopic tool takes close-ups at a distance with a field of view of about 30 cm (1 foot) at ten meters (33 feet) distance. But that’s just the first step for ChemCam. In step two eerily reminiscent of the heat rays described in War of the Worlds a powerful laser will focus through the same telescope at the target. The laser can heat a spot about a millimeter (0.04 inches) in diameter to nearly ten thousand degrees Celsius (18 thousand degrees Fahrenheit). The heat blows away dust, breaks off molecules, breaks up the molecules and even breaks apart atoms in the rocky target.

As a result, the target emits a spark of light. ChemCam can analyze the spark’s spectrum, identifying what elements carbon or silicon, for example the target contained. Called Laser-Induced Breakdown Spectroscopy, or LIBS, this technique is widely used on Earth but will be a first for Mars, says Roger C. Wiens, a planetary scientist at Los Alamos National Laboratory and the principal investigator on the ChemCam project. “LIBS is being used in a number of facets on earth. For example, a company that makes aluminum uses it to check the composition of their aluminum alloy in the molten state.”

Going into space is a different story. Seven years in the making, ChemCam will make MSL much faster than MER at choosing targets, Wiens says. “The Opportunity rover landed in a small crater and here in front of us sat a rock outcrop, which is the first one we had seen on Mars up close and personal. And it was less than ten meters away. [With the ChemCam] we could have immediately analyzed that rock before actually even driving the rover off the pad, and told them that here sits a sedimentary rock outcrop right in front of you. Instead, it took a number of days, and they drove up to the rock and actually sampled it with the contact instruments before they really determined that it was a sedimentary rock outcrop.” With its long optical reach, ChemCam can analyze objects out of reach of the rover’s mechanical arm, even overhead.

In addition, ChemCam will be able to do some chemical analysis of small parts of rock samples, before they are crushed and transported to MSL’s internal analytical instruments

“I think this instrument is going to see a lot of use,” Wiens says, “because we can take a lot of data rapidly. So one of the great things is that we can get a much larger database of rock samples than some of the in-situ techniques. I think it’s going to be an exciting instrument to build and fly.”

Palluconi sees MSL as an intermediary step between MER and the direct search for life on Mars. “I would regard MSL as being kind of a transition mission between the more conventional aspects of planetary exploration, which involve geology and geophysics and, in the case of Mars because of its atmosphere, the climate and weather to ones in the future which will make direct searches for life. So the overall objective of MSL is to make a habitability assessment of the area that the vehicle lands in on Mars.”

The Near Future
Because NASA decided only in December 2004, which of many scientific instruments proposed for MSL will actually fly, all of the scientists whose projects were chosen are scrambling to put the finishing touches on their instruments. “The mission is in phase A, which is a definition phase, so it’s really the earliest formal phase of the mission,” Palluconi says. “Right now the principle work on the science side is figuring out where to place the instruments on the rover, how to meet their thermal needs, how to ensure that they have the fields of view they need and that their other requirements are met. Of course, the vehicle itself is being designed at the same time and the design is being refined. So there’s quite a bit of work to do and we’re probably just about a year away from the preliminary design review, which on the 2009 launch schedule would occur next February.”

Some aspects of the Mars Science Laboratory remain up in the air. Many of the MSL scientific instruments require plenty of power. The proposed source of that power, a radioisotope power supply, requires presidential approval, which lies in the future. And in March 2005, NASA began considering the possibility of flying two MSL rovers in 2011 instead of one in 2009.

Original Source: NASA Astrobiology Magazine

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Cassini Set for Closest Titan Flyby

This map of Titan’s surface illustrates the regions that will be imaged by Cassini during the spacecraft’s close flyby of the smog-enshrouded moon on April 16, 2005. At closest approach, the spacecraft is expected to pass approximately 1,025 kilometers (640 miles) above the moon’s surface.

The colored lines delineate the regions that will be imaged at differing resolutions.

Images from this encounter will add to those taken during the March 31, 2005, flyby and improve the moderate resolution coverage of this region. The imaging coverage will include the eastern portion of territory observed by Cassini’s radar instrument in October 2004 and February 2005, and will provide a way to compare the surface as viewed by the different instruments. Such comparisons (see PIA06222) will provide insight into the nature of Titan’s surface.

The higher-resolution (yellow boxes) have been spread out around a central mosaic in order to maximize coverage of this region by the visual and infrared mapping spectrometer which will be observing simultaneously with the cameras of the imaging science subsystem.

The map shows only brightness variations on Titan’s surface (the illumination is such that there are no shadows and no shading due to topographic variations). Previous observations indicate that, due to Titan’s thick, hazy atmosphere, the sizes of surface features that can be resolved are a few times larger than the actual pixel scale labeled on the map.

The images for this global map were obtained using a narrow band filter centered at 938 nanometers — a near-infrared wavelength (invisible to the human eye). At this wavelength, light can penetrate Titan’s atmosphere to reach the surface and return through the atmosphere to be detected by the camera. The images have been processed to enhance surface details.

It is currently northern winter on Titan, so the moon’s high northern latitudes are not illuminated, resulting in the lack of coverage north of 35 degrees north latitude.

At 5,150 kilometers (3,200 miles) across, Titan is one of the solar system’s largest moons.

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 mission for NASA’s Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute, Boulder, Colo.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov . For additional images visit the Cassini imaging team homepage http://ciclops.org .

Original Source: NASA/JPL/SSI News Release

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One of the Earliest Stars Found

Image credit: ANU
A new star that may be one of the first to have formed in the Universe has been discovered by an international team led by ANU researchers.

The new star ? which goes by the innocuous name HE 1327-2326 ? is of enormous importance because it provides the crucial evidence of the time when the very first stars formed after the Big Bang.

?This star?s a record breaker ? it has the lowest levels of iron ever recorded in a star so far. This is of great importance because it indicates HE 1327-2326 formed in the very early Universe,? team leader and astronomy PhD student, Ms Anna Frebel said.

In general, stars with a low iron abundance compared to the Earth?s sun are called ?metal-poor? stars.

?Elements such as iron are only synthesised in the course of the lifetime of stars during the evolution of the Universe,? Ms Frebel said.

?Thus, we believe HE 1327-2326 formed shortly after the Big Bang ? it?s about twice as iron-poor as the previous record holder, HE 0107-5240, which was discovered in 2001 by ANU and German astronomers as part of the same survey.

?HE 1327-2326 will be used to trace the very early chemical enrichment history of the Universe as well as star formation processes and will challenge astronomers around the world ? it?s a pretty exciting prospect.?

The researchers first observed HE 1327-2326 using the European Southern Observatory?s 3.6-metre telescope in Chile. High quality data taken later with Japan?s 8-metre Subaru telescope in Hawaii revealed HE 1327-2326?s extraordinarily low iron content.

The star was discovered in a sample of about 1800 ?metal-poor? stars that are being investigated as part of Ms Frebel?s PhD project and is detailed in the latest edition of Nature in the paper Nucleosynthetic signatures of the first stars.

Research collaborators included Professor John Norris from the Research School of Astronomy and Astrophysics, Dr Wako Aoki from the National Astronomical Observatories of Japan and Dr Norbert Christlieb from Hamburger Sternwarte in Germany, as well as other researchers in Sweden, the US, the UK, Japan and Australia.

?HE 1327-2326 is a very unusual object in many ways for us astronomers,? Professor Norris, Ms Frebel?s supervisor, said. ?Relative to its iron levels has abnormally high levels of several elements including carbon, nitrogen and strontium.

?Another very interesting and unusual observation is that no lithium could be detected in the relatively unevolved star. A yet unknown process must have led to depletion of that element.

?Stars that formed later in the history of the Universe tend to have more predictable ratios of these elements,? Professor Norris said.

Ms Frebel said there could be several scenarios that explain the unusual features of HE 1327-2326.

?An explanation could be that only one explosion of one of the first stars in the Universe happened, which led to pollution of the surrounding gas cloud with elements heavier than hydrogen, helium and lithium in which stars like HE 1327-2326 might have formed,? she said.

?However, it can not be excluded that HE 1327-2326 formed just after the Big Bang and there was little time for the iron content to develop and therefore is actually one of the ?first stars? itself ? although as yet no genuine ?first star? has been found.?

Original Source: ANU News Release