Posted on by Fraser Cain

Spiral Galaxy NGC 2403

Spiral Galaxy NGC 2403. Image credit: Subaru. Click to enlarge.
Subaru Telescope, using Suprime-Cam, took the clearest most complete image to date of the spiral galaxy NGC 2403. At a distance of 10 million light years, NGC 2403 is an Sc type galaxy, which has open spiral arms and a small nucleus. It is approximately half the mass of our own galaxy, the Milky Way, and has an abundance of neutral hydrogen gas. In the spiral arms we see active star formation regions in red, clusters of young blue stars called OB associations, and darker regions called dust lanes where light is blocked by gas and dust within the galaxy.

This is not the first time NGC 2403 has been studied. Edwin Hubble used NGC 2403 as evidence that more distant galaxies move more quickly away from us, now called Hubble’s Law. It was also used to develop the Tully-Fisher relation, which states that there is a relation between a galaxy’s rotational speed and its brightness. NGC 2403 has become an important standard galaxy when deciding the distances to other galaxies, as we recognize the vast expanse of space.

Larger galaxies are thought to have developed from the collision and merger of smaller galaxies. Mergers can leave enduring marks on a galaxy’s halo, the most extended and generally spherical component of a galaxy. There is evidence that relatively young stars exist in the halo of NGC 2403, hinting at a recent merger with another galaxy. Astronomers are now studying this image to see if the color and brightness of the stars in the halo of NGC 2403 will reveal conclusive evidence of past mergers.

Original Source: Subaru News Release

Posted on by Fraser Cain

New Advances for Liquid-Fueled Rockets

An artist’s rendering of the Integrated Powerhead Demonstrator. Image credit: NASA. Click to enlarge.
When you think of future rocket technology, you probably think of ion propulsion, antimatter engines and other exotic concepts.

Not so fast! The final chapter in traditional liquid-fueled rockets has yet to be written. Research is underway into a new generation of liquid-fueled rocket designs that could double performance over today’s designs while also improving reliability.

Liquid-fueled rockets have been around for a long time: The first liquid-powered launch was performed in 1926 by Robert H. Goddard. That simple rocket produced roughly 20 pounds of thrust, enough to carry it about 40 feet into the air. Since then, designs have become sophisticated and powerful. The space shuttle’s three liquid-fueled onboard engines, for instance, can exert more than 1.5 million pounds of combined thrust en route to Earth orbit.

You might assume that, by now, every conceivable refinement in liquid-fueled rocket designs must have been made. You’d be wrong. It turns out there’s room for improvement.

Led by the US Air Force, a group consisting of NASA, the Department of Defense, and several industry partners are working on better engine designs. Their program is called Integrated High Payoff Rocket Propulsion Technologies, and they are looking at many possible improvements. One of the most promising so far is a new scheme for fuel flow:

The basic idea behind a liquid-fueled rocket is rather simple. A fuel and an oxidizer, both in liquid form, are fed into a combustion chamber and ignited. For example, the shuttle uses liquid hydrogen as its fuel and liquid oxygen as the oxidizer. The hot gases produced by the combustion escape rapidly through the cone-shaped nozzle, thus producing thrust.

The details, of course, are much more complicated. For one, both the liquid fuel and the oxidizer must be fed into the chamber very rapidly and under great pressure. The shuttle’s main engines would drain a swimming pool full of fuel in only 25 seconds!

This gushing torrent of fuel is driven by a turbopump. To power the turbopump, a small amount of fuel is “preburned”, thus generating hot gases that drive the turbopump, which in turn pumps the rest of the fuel into the main combustion chamber. A similar process is used to pump the oxidizer.

Today’s liquid-fueled rockets send only a small amount of fuel and oxidizer through the preburners. The bulk flows directly to the main combustion chamber, skipping the preburners entirely.

One of many innovations being tested by the Air Force and NASA is to send all of the fuel and oxidizer through their respective preburners. Only a small amount is consumed there–just enough to run the turbos; the rest flows through to the combustion chamber.

This “full-flow staged cycle” design has an important advantage: with more mass passing through the turbine that drives the turbopump, the turbopump is driven harder, thus reaching higher pressures. Higher pressures equal greater performance from the rocket.

Such a design has never been used in a liquid-fueled rocket in the U.S. before, according to Gary Genge at NASA’s Marshall Space Flight Center. Genge is the Deputy Project Manager for the Integrated Powerhead Demonstrator (IPD)–a test-engine for these concepts.

“These designs we’re exploring could boost performance in many ways,” says Genge. “We’re hoping for better fuel efficiency, higher thrust-to-weight ratio, improved reliability–all at a lower cost.”

“At this phase of the project, however, we’re just trying to get this alternate flow pattern working correctly,” he notes.

Already they’ve achieved one key goal: a cooler-running engine. “Turbopumps using traditional flow patterns can heat up to 1800 C,” says Genge. That’s a lot of thermal stress on the engine. The “full flow” turbopump is cooler, because with more mass running through it, lower temperatures can be used and still achieve good performance. “We’ve lowered the temperature by several hundred degrees,” he says.

IPD is meant only as a testbed for new ideas, notes Genge. The demonstrator itself will never fly to space. But if the project is successful, some of IPD’s improvements could find their way into the launch vehicles of the future.

Almost a hundred years and thousands of launches after Goddard, the best liquid-fueled rockets may be yet to come.

Original Source: NASA Science Article

Posted on by Fraser Cain

Spitzer’s Stunning Portrait of Andromeda

Giant mosaic of Andromeda made up of 11,000 images. Image credit: NASA/JPL. Click to enlarge.
NASA’s Spitzer Space Telescope has captured a stunning infrared view of Messier 31, the famous spiral galaxy also known as Andromeda.

Andromeda is the most-studied galaxy outside our own Milky Way, yet Spitzer’s sensitive infrared eyes have detected captivating new features, including bright, aging stars and a spiral arc in the center of the galaxy. The infrared image also reveals an off-centered ring of star formation and a hole in the galaxy’s spiral disk of arms. These asymmetrical features may have been caused by interactions with the several satellite galaxies that surround Andromeda.

“Occasionally small satellite galaxies run straight through bigger galaxies,” said Dr. Karl Gordon of the Steward Observatory, University of Arizona, Tucson, lead investigator of the new observation. “It appears a little galaxy punched a hole through Andromeda’s disk, much like a pebble breaks the surface of a pond.”

The new false-color Andromeda image is available at http://www.spitzer.caltech.edu/spitzer/ .

Approximately 2.5 million light-years away, Andromeda is the closest spiral galaxy and is the only one visible to the naked eye. Unlike our Milky Way galaxy, which we view from the inside, Andromeda is studied from the outside. Astronomers believe that Andromeda and the Milky Way will eventually merge together.

Spitzer detects dust heated by stars in the galaxy. Its multiband imaging photometer’s 24-micron detector recorded approximately 11,000 separate infrared snapshots over 18 hours to create the new comprehensive mosaic. This instrument’s resolution and sensitivity is a vast improvement over previous infrared technologies, enabling scientists to trace the spiral structures within Andromeda to an unprecedented level of detail.

“In contrast to the smooth appearance of Andromeda at optical wavelengths, the Spitzer image reveals a well-defined nuclear bulge and a system of spiral arms,” said Dr. Susan Stolovy, a co-investigator from the Spitzer Science Center at the California Institute of Technology, Pasadena.

The galaxy’s central bulge glows in the light emitted by warm dust from old, giant stars. Just outside the bulge, a system of inner spiral arms can be seen, and outside this, a well-known prominent ring of star formation.

NASA’s Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer mission for NASA’s Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology. The Jet Propulsion Laboratory is a division of Caltech.

Original Source: NASA/JPL News Release

Posted on by Fraser Cain

Ariane Rocket Blasts Off with Two Satellites

Ariane 5 rocket with two satellites on board. Image credit: ESA. Click to enlarge.
Just after midnight an Ariane 5GS successfully lifted off from Europe?s Spaceport in French Guiana. The two solid boosters ignited 7 seconds after the start-up of the cryogenic main stage, providing the power needed to lift the heavy launcher off the pad.

On board was a Syracuse 3A, built by Alcatel Alenia Space for the French Ministry of Defence and a Galaxy 15 communications satellite built by Orbital Sciences Corporation, USA, for the American company PanAmSat. Galaxy 15 is the 20th satellite to be launched by Ariane launchers for this satellite communications operator.

On arriving at orbital injection, around 26 minutes after launch, the Ariane 5 was at an altitude of about 1560 km and travelling at approximately 8633 metres a second. Syracuse 3A was the first satellite to be released, followed approximately 10 minutes later by the Galaxy 15. Both satellites have been placed in the targeted geostationary transfer orbit with very high precision.

Flight 168 is the 23rd Ariane 5 launch.

Original Source: ESA News Release

Posted on by Fraser Cain

Stars Form Near the Heart of the Milky Way

Chandra image of Sgr A*. Image credit: Chandra. Click to enlarge.
NASA’s Chandra X-ray Observatory revealed a new generation of stars spawned by a super-massive black hole at the center of the Milky Way galaxy. This novel mode of star formation may solve several mysteries about these super-massive black holes that reside at the centers of nearly all galaxies.

“Massive black holes are usually known for violence and destruction,” said Sergei Nayakshin of the University of Leicester, United Kingdom. “So it’s remarkable this black hole helped create new stars, not just destroy them.”

Black holes have earned their fearsome reputation because any material, including stars, that falls within their “event horizon” is never seen again. These new results indicate immense disks of gas, orbiting many black holes at a safe distance from the event horizon, can help nurture the formation of new stars. This conclusion comes from new clues that could only be revealed in X-rays. Until the latest Chandra results, researchers have disagreed about the origin of a mysterious group of massive stars discovered by infrared astronomers.

The stars orbit less than a light year from the Milky Way’s central black hole, which is known as Sagittarius A* (Sgr A*). At such close distances to Sgr A*, the standard model for star forming gas clouds predicts they should have been ripped apart by tidal forces from the black hole. Two models, based on previous research, to explain this puzzle have been proposed. In the disk model, the gravity of a dense disk of gas around Sgr A* offsets the tidal forces and allows stars to form.

In the migration model, the stars formed in a cluster far away from the black hole and then migrated in to form the ring of massive stars. The migration scenario predicts about a million low mass, sun-like stars in and around the ring. In the disk model, the number of low mass stars could be much less.

Researchers used Chandra observations to compare the X-ray glow from the region around Sgr A* to the X-ray emission from thousands of young stars in the Orion Nebula star cluster. They found the Sgr A* star cluster contains only about 10,000 low mass stars, thereby ruling out the migration model. Because the galactic center is shrouded in dust and gas, it has not been possible to look for the low-mass stars in optical observations. X-ray data have allowed astronomers to penetrate the veil of gas and dust and look for these low mass stars.

This research, coauthored by Nayakshin and Rashid Sunyaev of the Max Plank Institute for Physics in Garching, Germany, will appear in an upcoming issue of the Monthly Notices of the Royal Astronomical Society.

“In one of the most inhospitable places in our galaxy, stars have prevailed,” Nayakshin said. “It appears star formation is much more tenacious than we previously believed.” “We can say the stars around Sgr A* were not deposited there by some passing star cluster, rather they were born there,” Sunyaev said. “There have been theories that this was possible, but this is the first real evidence. Many scientists are going to be very surprised by these results.”

The research suggests the rules of star formation change when stars form in the disk surrounding a giant black hole. Because this environment is very different from typical star formation regions, there is a change in the proportion of stars that form. For example, there is a much higher percentage of massive stars in the disks around black holes.

NASA’s Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass. For more information about this research on the Web, visit:

Additional information and images are available at:

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

Original Source: Chandra News Release

Posted on by Mark Mortimer

Book Review: Heavenly Intrigue

Tycho Brahe was a Danish nobleman who spent his life taking the most exact measurements of stars and planets then known. Being of high ranked noble birth, his family’s expectations were for Brahe to enter into court politics. Yet Brahe followed his own path, that being his love for astronomy. Even his slight divergence into alchemy quickly returned to astronomy on seeing the skies brighten from a supernova. Nevertheless, this being Europe of the early 1600’s, politics dominated lives. Brahe was exiled when a new king sat upon the Danish throne and he ended up in Prague as the mathematician of the court of the Holy Roman Empire.

At almost the same time, Johannes Kepler was using his intellect to escape his difficult and lowly lifestyle. Earning passage into a university, he excelled at mathematics and also fell into a love of astronomy and astrology. Kepler equally had difficulties in life and though he married a lady who had extensive land holdings, all their wealth disappeared. The politics of the time was again the culprit. Fortuitously, Kepler had already connected with Tycho Brahe who had given him an invitation to work and live together. Kepler, apparently without any other options, accepted. Much later, after Brahe’s death, Kepler used Brahe’s data to determine his now well known three laws of planetary motion.

Most references, in discussing Brahe and Kepler, provide little more information than the above. The Gilders, however, have gone digging. With the help of many experts and original documents, they build the characters of these scientists. Brahe may have been a nobleman, but he seems to have continually turned his back to the corresponding lifestyle. Kepler was not only smart with numbers but also had a tendency to quickly lose friends through a hot temper. Many details of their lives get reviewed; their parents, their places of birth, their schooling and their relationships. Yet this is not a simple biography of these two individuals. This is a case of murder. For the authors show that Kepler, with his temper and his craving for fame, wanted and needed Brahe’s data to pursue his own postulations about the shape of the heavens.

The key element in the Gilder’s book comes from recent investigations. Brahe’s crypt was recently repaired and, given this opportunity, some hairs were analyzed to try to deduce the cause of his death. The authors use tools of today’s forensic experts to understand a bit of what was happening with Brahe during his final days. In so doing, they combine these results with many pieces of circumstantial evidence to substantiate their belief that Kepler had the opportunity, means and motive. This case is a bit cold, actually more than 400 years old, but the Gilders make it fresh and exciting by reliving the times of these scientists and making the two much more than footnotes in a physics text.

This ability to enliven a well aged event sets this book apart. Very little science graces its pages. Some description of Brahe’s observatories and sextants show the state of the art in astronomical observation. A little on Kepler’s Mysterium Cosmographicum give an idea of the philosophical issues of the times. For the most part, the Gilders dish up a finely flavoured selection of the pertinent points and issues that embellish their belief of a dastardly deed. A delicious undertone questions the drive of scientists and society. That is, just how far outside society’s mores do we allow researchers when the result adds knowledge or ability for all. The answer to this question might have changed in 400 years, but it is still relevant to ask today.

People come in all stripes and colours. Brilliant scientists might be lousy friends. Fantastic leaders might be so inept with numbers as to be unable to balance their own finances. This potpourri of characteristics bring spice to our lives. However, some spices are not as well liked as others. The murder that Joshua Gilder and Anne-Lee Gilder so boldly proclaim in their book Heavenly Intrigue is one such. Perhaps a golden opportunity brought together Johannes Kepler and Tycho Brahe, but read this book and see how other opportunities may have prematurely ended their association.

Review by Mark Mortimer

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

Posted on by Fraser Cain

New Details About Space Shuttle Successor

Artist illustration of the new Crew Exploration Vehicle. Image credit: Northrop Grumman. Click to enlarge.
A Northrop Grumman-Boeing team has unveiled its plans to design and build NASA’s proposed Crew Exploration Vehicle, a successor to the space shuttle that will carry humans to the International Space Station by 2012 and back to the moon by 2018. Shown in these artist concepts, the new, modular space vehicle comprises a crew module reminiscent of the Apollo spacecraft, a service module and a launch-abort system.

A Northrop Grumman-Boeing team has unveiled its plans to design and build NASA’s proposed Crew Exploration Vehicle, a successor to the space shuttle that will carry humans to the International Space Station by 2012 and back to the moon by 2018. Shown in these artist concepts, the new, modular space vehicle comprises a crew module reminiscent of the Apollo spacecraft, a service module and a launch-abort system.

The CEV comprises a crew module that builds on NASA’s Apollo spacecraft, a service module and a launch-abort system. It is designed to be carried into space aboard a shuttle-derived launch vehicle — a rocket based on the solid rocket booster technology that powers the early phases of current shuttle flights.

The CEV will be produced both as a crewed space transportation system and as an uncrewed space vehicle capable of transporting cargo to and from the International Space Station. NASA expects to select a CEV prime contractor in the spring of 2006.

According to Doug Young, program manager for the Northrop Grumman-Boeing CEV team, the team’s design approach to the CEV and the overall mission architecture have been evolving over the past year.

“We’ve been working closely with NASA to identify design options and technologies that would enable the nation to meet its space exploration goals of safety, affordability and reliability,” Young said. “Early on we concluded that this modular, capsule-based approach would establish an ideal foundation for a successful, sustainable human and robotic space exploration program. It’s also a system that can be designed and built today using proven technologies, which will help maintain the nation’s leadership role in human space flight.”

While similar in shape to the Apollo spacecraft that carried astronauts to the moon in the late ’60s and early ’70s, the new CEV is a quantum leap forward in terms of performance, reliability and on-orbit mission capability.

“The CEV we plan to build will benefit not so much from a single, technical breakthrough but rather from evolutionary improvements in structural technologies, electronics, avionics, thermal-management systems, software and integrated system- health-management systems over the past 40 years,” said Leonard Nicholson, the Northrop Grumman-Boeing team’s deputy program manager.

According to Nicholson, the CEV offers many fundamental improvements over Apollo. Among them:

– CEV’s crew module will have much more internal volume than the Apollo capsule, but will only be slightly heavier, due to the use of advanced structural materials and technologies that reduce the size, weight and power consumption of key subsystems.

– CEV’s crew module will carry up to six astronauts, while Apollo carried just three.

– CEV will carry more fuel for lunar return than Apollo, allowing it to change its orbit rather than relying on the moon and the Earth to be in the right relative positions.

– CEV will be able to operate as an autonomous spacecraft orbiting the moon for up to six months while its crew of four descends to the lunar surface in the lunar lander. Crew members and ground controllers will be able to communicate with the CEV and monitor its “vital signs” remotely. During the Apollo era, one astronaut stayed with the “mother ship” while the lunar lander carrying two astronauts descended to the moon.

– CEV will use two fault-tolerant subsystems and integrated system-health- management systems to allow it to detect, isolate and recover from subsystem failures. By comparison, Apollo generally had only single fault tolerance.

A unit of The Boeing Company, Boeing Integrated Defense Systems is one of the world’s largest space and defense businesses. Headquartered in St. Louis, Boeing Integrated Defense Systems is a $30.5 billion business. It provides network-centric system solutions to its global military, government and commercial customers. It is a leading provider of intelligence, surveillance and reconnaissance systems; the world’s largest military aircraft manufacturer; the world’s largest satellite manufacturer and a leading provider of space-based communications; the primary systems integrator for U.S. missile defense; NASA’s largest contractor; and a global leader in sustainment solutions and launch services.

Northrop Grumman Corporation is a global defense company headquartered in Los Angeles, Calif. It provides technologically advanced, innovative products, services and solutions in systems integration, defense electronics, information technology, advanced aircraft, shipbuilding and space technology. With more than 125,000 employees, and operations in all 50 states and 25 countries, the company serves U.S. and international military, government and commercial customers. Today, more than 20,000 of Northrop Grumman’s employees are devoted to space-related projects.

Original Source: Northrop Grumman News Release