Posted on by Ken Kremer

First Orion Capsule forming rapidly

The first mated Forward Assembly of an Orion Crew Module has been built by Lockheed Martin team at NASA Michoud Assembly Facility by welding together the Cone Assembly and the Crew Tunnel segments during May 2010. The final weld for the Ground Test Article (GTA) will join this Forward Assembly to the Aft Assembly. An aeroshell covered with thermal protection tiles will be attached later after the GTA skeleton is completed and mass simulators have been installed inside. Astronauts would enter the International Space Station through the tunnel after docking. Credit: Lockheed Martin

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The first Orion crew capsule is rapidly taking shape as assembly work to construct the skeletal framework of the first pathfinder Orion capsule – the Ground Test Article – or GTA, is nearing completion.

The Lockheed Martin team building Orion is just one weld away from completing the framework of an Orion cabin at NASA’s Michoud Assembly Facility in New Orleans. Precision welding to join together the final large skeletal segments (see my earlier report) has proceeded well according to Lockheed managers I spoke with.

“The Orion capsule is the Congressionally approved program of record and we are moving forward with it”, says Larry Price, Lockheed’s Orion Deputy Program Manager in an interview with me. “Our work is continuing with the funding which is still approved until September 2010. Orion is a very functional vehicle. All subsystems will be state of the art.

“Orion is not Apollo on Steroids”, Price emphasized.

“We are building on what is known and it’s a very contemporary approach. The flight avionics are very similar to commercial airliners. We can take advantage of the latest advances in avionics and computing. Orion has been designed for long duration interplanetary functionality to operate beyond Low Earth Orbit (LEO) for 6 months or more to visit the Moon, Asteroids, Lagrange points and other targets of interest for scientific investigation”, Price explained.

The Orion Cone assembly for the GTA is shown here with “Confidence panels” and equipment slings and clamps which were used to “practice“ and validate the crucial friction stir welding procedures for welding together the hardware segments which form the first Orion GTA pathfinder vehicle. Credit: Lockheed Martin

“The Orion project status is we have just one more weld remaining on the crew cabin”, says Tim Knowles. He is the Orion GTA Vehicle manager for Lockheed Martin and discussed Orion development in an interview with me. “When all follow on work to prepare the GTA is done, the final Orion GTA crew cabin will look very much like a real Orion capsule,” Knowles said.

“The final close out weld will join the Forward Cone Assembly and Crew Tunnel to the barrel shaped Aft Assembly. This combined piece then comprises the habitable volume and forms the first structural framework for the first Orion Crew Cabin”.

Interior view of Cone Assembly and crew hatch welded to the mid-ring (silver colored) at base. The 5 meter diameter Cone Assembly weighs about 650 lbs and will be welded to the Aft Assembly. The 18 cm thick mid-ring joins the barrel of the Aft Assembly to the Cone. The bent “T” shaped ring adds stiffness to the structure and also provides an attach point for the aeroshell support structure. Credit: Lockheed Martin
“Inside the Aft Assembly is the backbone skeleton which provides structural stiffness to the cabin and also hardware mounting locations. The Aft Assembly is where the crew seats, storage lockers and other systems are installed onto compartments inside the backbone skeleton”.

“The welding process uses a technique called Friction Stir Welding (FSW)”, Knowles said. “It has produced acceptable results so far. It’s a learning process and not flawless, and improves each time we do it” added Knowles.

Orion Crew Module Cone for the Ground Test Article is hoisted and moved in preparation for welding at the NASA Michoud Assembly Facility in New Orleans, La. Credit: Lockheed Martin
The welds for the final large segments ranged from about 300 to 450 inches in length. “These are the longest FSW welds ever attempted”, according to Larry Price.

“We use sound to evaluate the work and detect any flaws”, explained Knowles. “The testing method is called Phased Array Ultrasonic Testing (PAUT). It’s a Non-Destruction Evaluation (NDE) technique. Remember, the GTA is intended as a manufacturing pathfinder as well as a structural test article”.

“The actual welding times to combine the individual segments requires only about 45 minutes to an hour. Of course the real trick to getting a good weld is that it takes many many days of preparation work to get the parts and equipment and everything else set up properly,” explained Knowles.

Orion Aft Assembly, with Barrel and Bulkhead, will house the Backbone Assembly and be welded to the Forward Cone/Tunnel Assembly to form the complete Orion GTA structural assembly Credit: Lockheed Martin

“Most of the work on the parts needed to complete the GTA after completion of the welding is well along. They will be installed inside following a pressure test of the crew cabin that is scheduled for June. These include mass and volume simulators for items like the crew seats and consoles, lockers, waste management etc. On the outside we’ll add simulators for the parachutes, compressed gases, propellants and thrusters all around the shell we welded together”.

“Then we’ll add the simulated [cone shaped] thermal protection system (TPS) aeroshell around that, including a few real TPS tiles. We will also add a heat shield.”

“When we are done adding everything, the final Orion GTA will look very much like a real flight article of the Orion capsule”.

Mock up of the Orion Capsule at the Kennedy Space Center Visitor Center. 4300 people are working on the Orion project across the US. Credit: Ken Kremer

“The GTA will then be placed in a chamber and bombarded with acoustic energy for environmental correlation tests. These tests simulate the flight environment to collect data for the purpose of comparing the results to our predictive models, updating the models, and then refining the design of the crew cabin”.

“We are planning to ship the GTA to our Lockheed facility in Denver around the end of October. It will be integrated with a simulated Launch Abort System to form a launch abort vehicle (LAV) that will subjected to further vibro-acoustic tests next spring. Then the GTA crew module will be shipped to NASA Langley for water drop landing testing to simulate the impact. Those tests will run into 2012”.

“About 86 people are currently working on various aspects of the Orion GTA project at Michoud”, according to Lockheed spokesman Kevin Barre.

The GTA is a key pathfinder vehicle and the first full-sized, flight-like test article for Orion. It will be subjected to numerous stringent tests which are crucial learning exercises that will help validate the cabin design and will be used to incorporate changes to the tools and manufacturing processes that will eventually lead to a human rated production vehicle.

This Orion GTA capsule is an indispensible forerunner to the next generation Orion vehicle which NASA had planned for human flights to shot to the Moon and the International Space Station (ISS). It is not an unmanned “rescue capsule”, or lifeboat, as recently proposed by President Obama at his April 15 space policy speech at the Kennedy Space Center (KSC).

President Obama’s new announcement to resuscitate Orion as a “rescue capsule” was a significant refinement to his original plan of February 2010 to wholly terminate Orion and Project Constellation as part of his initial 2011 NASA Budget proposal which would radically alter the future path of NASA.

Related stories by Ken Kremer

3 Welds to Go for 1st Orion Pathfinder Vehicle

Orion can Launch Safely in 2013 says Lockheed

Posted on by Nancy Atkinson

Amateur Astronomers Spy on Air Force’s Secret Mini Space Plane

Artist impression of the Boeing X-37B (USAF)

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The US Air Force’s unmanned mini space shuttle has been located and tracked in orbit by a contingent of amateur astronomers, and now you can see the X37-B for yourself.

The spaceplane was spotted independently by amateur satellite watchers Greg Roberts of Cape Town, South Africa, and Kevin Fetter of Brockville, Canada, on May 20. Another satellite watcher, Ted Molczan, of Toronto, Canada was then able to calculate the spacecraft’s actual orbit. Then, from that data, Fetter was able to find the X37-B again the following night and photograph it flying across the starry sky. See more images on Spaceweather.com, and this movie of the X37-B in orbit, as seen by Fetter.

Click here to find out use Spaceweather.com’s satellite tracking tool to find out if the X37-B will be flying over your backyard.

They also have an iPhone app.

Spotters say the space plane is about as bright as some of the stars in the Big Dipper, at +2.8 magnitude or so.

If you capture an image of the X37-B in orbit, send it to us, or submit it on Spaceweather.com’s site.

Just what is the mission of this secret mini space shuttle? There’s been lots of speculation, but read our previous article based on facts here.

Source: Spaceweather.com

Posted on by Nancy Atkinson

SDO Seeing ‘Butterfly Effect’ on the Sun

A new view of the sun from the Solar Dynamics Observatory. Credit: NASA

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Already, the Solar Dynamics Observatory, or SDO, has taken over 5 million images, and the firehose of data and spectacular images is allowing solar scientists to begin understanding the dynamic nature of solar storms. With SDO, scientists are seeing that even minor solar events can have large effects across the Sun. “In essence, we are watching the butterfly effect in action on the Sun,” said Dean Pesnell, SDO project scientist.

The Atmospheric Imaging Assembly (AIA), one of three instruments aboard SDO, records high-resolution full-disk images of the Sun’s corona and chromosphere in more channels and at a higher rate than ever before. “This will allow us to zoom in on small regions and see far more detail in time and space, and zoom in on any part we want,” said Pesnell. “By looking at entire Sun we can see how one part of the Sun affects another. You can then zoom in to measure the changes in great detail.”

Large eruptive prominence on the sun's edge, as seen by SDO. Credit: NASA

Shortly after AIA opened its doors on March 30, scientists observed a large eruptive prominence on the sun’s edge, followed by a filament eruption a third of the way across the star’s disk from the eruption.

“Even small events restructure large regions of the solar surface,” said Alan Title, AIA principal investigator at Lockheed Martin Advanced Technology Center. “It’s been possible to recognize the size of these regions because of the combination of spatial, temporal and area coverage provided by AIA.”

At the 216th American Astronomical Society meeting this week, Title said that some of the initial data from SDO is providing maps of magnetic fields and movies that are giving scientists some confidence in trying to decipher the cause and effect of solar storms

AIA observed a number of very small flares that have generated magnetic instabilities and waves with clearly-observed effects over a substantial fraction of the solar surface. The instrument is capturing full-disk images in eight different temperature bands that span 10,000 to 36-million degrees Fahrenheit. This allows scientists to observe entire events that are very difficult to discern by looking in a single temperature band, at a slower rate, or over a more limited field of view.

Solar storms produce disturbances in electromagnetic fields that can induce large currents in wires, disrupting power lines and causing widespread blackouts here on Earth. The storms can interfere with global positioning systems, cable television, and communications between ground controllers and satellites and airplane pilots flying near Earth’s poles. Radio noise from solar storms also can disrupt cell phone service.

To help scientists and the public to understand and have access to the large amount of data being returned by SDO, the science team has built some tools to help communicate the data.

New websites will help researchers find data sets relative to their topics of interest and provide an overview to the casual observer.

“SDO generates as much data in a single day as the TRACE mission produced in five years,” said Neal Hurlburt from SDO mission, from Lockheed Martin. “We want to share it with the public, but we want to do it in an effective way, so we developed the Heliophysics Events Knowledgebase (HEK) and the Sun Today Website.”

The Sun Today website displays the current state of events on the sun. These can guide researchers and others to more detailed descriptions and access to associated SDO data.

HEK includes the Event and Coverage Registries (HER, HCR), Inspection & Analysis Tools, Event Identification System and Movie Processing. Event services enable web clients to interact with the HEK.

There is also a tutorial on how to work with the data, and extract images and movies from the SDO data.

More info: SDO website.

Posted on by Nancy Atkinson

The Story Behind SOFIA, NASA’s Flying Observatory

The Boeing 747SP used for the SOFIA project is 45 feet shorter than a modern 747, making it lighter and more able to make long transoceanic flights without stopping to refuel. Credit: Lauren Gold/Cornell Chronicle

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From the Cornell University Chronicle, written by Lauren Gold:

The SOFIA project has been in the making for more than 13 years — but the airplane has an even longer history. Originally owned by Pan Am, the 747SP (Special Performance) was named the Clipper Lindbergh and christened by Anne Morrow Lindbergh in 1977 on the 50th anniversary of Lindbergh’s flight across the Atlantic.

The Boeing 747SP differs from a modern 747 in a few ways. Most notably, it’s 45 feet shorter and, thus, lighter — which allowed it to make long transoceanic flights without stopping to refuel. (Modern 747s have much more efficient engines.)

The plane already had two Cornell connections long before astronomy professor and principal investigator Terry Herter and his team installed FORCAST onto the telescope in February.

When Boeing was designing the plane in the 1970s, they hired a young Cornell mechanical engineering graduate to design its horizontal stabilizer (which allows the pilot to raise or lower the nose of the plane in flight). That engineer, Bill Nye ’77, eventually went on to become “Bill Nye the Science Guy” — the Emmy Award-winning science educator and Cornell Frank H.T. Rhodes Class of 1956 Professor from 2001 to 2006.

A decade later in 1989, when the plane was in commercial service, George Gull, Cornell research support specialist and now lead engineer for FORCAST, just happened to notice the “Clipper Lindbergh” insignia on his plane when he flew from Hong Kong to San Francisco after a Cornell Glee Club trip to China.

So while Gull won’t be one of the lucky few on the plane for the May 25 first light flight — he can boast having flown on the plane 21 years before everyone else on the team.

Since NASA bought the Clipper Lindbergh in 1997, SOFIA has undergone more than a few changes. Among many other things, it has a 16-by-23-foot door cut into the port side for the telescope and a bump near the rear of the plane that smoothes out airflow around the fuselage when the telescope door is open.

Currently, a grid of what looks like hundreds of small dots — actually pieces of yarn — cover the surface of the telescope door and the area around it. The yarn is a low-tech but effective way of optimizing aerodynamics — researchers flying alongside SOFIA in a chase plane videotape the yarn’s motion to analyze air flow around the door. The yarn will be removed when the observatory goes into regular operation.

Inside, the plane has a few remnants of its past: several original seats; the spiral staircase to the upper deck; an array of analog instruments in the cockpit. But most of the seats are a hodgepodge of military airplane seats at workstations, facing backward toward the massive, 17-ton telescope and instruments.

The cabin also includes an area for educators and reporters who will take part in flights as part of the mission’s effort to educate and engage the public. And the telescope itself is part of a pressure bulkhead that allows the main cabin to stay pressurized despite the open door behind it.

Despite its novelty, SOFIA follows a long history of airborne astronomy that started with observations made from biplanes in the 1920s and ’30s. Most recently, NASA’s Kuiper Airborne Observatory, a modified Lockheed C-141 with a 1-meter infrared telescope that operated 1974-95, was the vehicle for discoveries including the rings around Uranus, the atmosphere around Pluto and the presence of water vapor in the interstellar medium.

Source: Cornell

Posted on by Nancy Atkinson

Wild and Crazy Multi-Planetary System Surprises Astronomers

Epsilon Andromedae. Illustration Credit: NASA, ESA, and A. Feild (STScI) Science Credit: NASA, ESA, and B. McArthur, University of Texas at Austin, McDonald Observatory.

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Astronomers are finding that not only are there a wide range of different extrasolar planets, but there are different types of planetary systems, as well. “We’re not in Kansas anymore as far as solar systems go,” said Barbara McDonald from the University of Texas’ McDonald Observatory, at the American Astronomical Society meeting in Miami, Florida today. “The exciting thing is, we found another multi-planet system that is not at all like our own.”

A close look at the Upsilon Andromedae system with the Hubble Space Telescope, the Hobby-Eberly Telescope and other ground-based telescopes shows a whacky system where planets are out of tilt and have highly inclined orbits. The astronomers also found another planet, and also another star – this is likely a binary star system.

Even with Pluto’s inclined orbit, our solar system looks like an ocean of calm compared to Upsilon Andromedae.

Comparison of solar systems. Credit: HubbleSite

McDonald said these surprising findings will impact theories of how multi-planet systems evolve, and it shows that some violent events can happen to disrupt planets’ orbits after a planetary system forms.

“The findings mean that future studies of exoplanetary systems will be more complicated,” she said. “Astronomers can no longer assume all planets orbit their parent star in a single plane.” says Barbara McArthur of The University of Texas at Austin’s McDonald Observatory.

Similar to our Sun in its properties, Upsilon Andromedae lies about 44 light-years away. It’s a little younger, more massive, and brighter than the Sun. For just over a decade, astronomers have known that three Jupiter-type planets orbit the yellow-white star Upsilon Andromedae.

But after over a thousand combined observations, McDonald and her team uncovered hints that a fourth planet, e, orbits the star much farther out. They were also able to determine the exact masses of two of the three previously known planets, Upsilon Andromedae c and d. Much more startling, though, is that not all planets orbit this star in the same plane. The orbits of planets c and d are inclined by 30 degrees with respect to each other. This research marks the first time that the “mutual inclination” of two planets orbiting another star has been measured.

“Most probably Upsilon Andromedae had the same formation process as our own solar system, although there could have been differences in the late formation that seeded this divergent evolution,” McArthur said. “The premise of planetary evolution so far has been that planetary systems form in the disk and remain relatively co-planar, like our own system, but now we have measured a significant angle between these planets that indicates this isn’t always the case.”

Until now the conventional wisdom has been that a big cloud of gas collapses down to form a star, and planets are a natural byproduct of leftover material that forms a disk. In our solar system, there’s a fossil of that creation event because all of the eight major planets orbit in nearly the same plane. The outermost dwarf planets like Pluto are in inclined orbits, but these have been modified by Neptune’s gravity and are not embedded deep inside the Sun’s gravitational field.

So what knocked the Upsilon Andromedae system around?

“Possibilities include interactions occurring from the inward migration of planets, the ejection of other planets from the system through planet-planet scattering, or disruption from the parent star’s binary companion star, Upsilon Andromedae B,” McArthur said.

Or, the companion star – a red dwarf less massive and much dimmer than the Sun — could be the culprit. is.

“We don’t have any idea what its orbit is,” said team member Fritz Benedict. “It could be very eccentric. Maybe it comes in very close every once in a while. It may take 10,000 years.” Such a close pass by the secondary star could gravitationally perturb the orbits of the planets.”

The two different types of data combined in this research were astrometry from the Hubble Space Telescope and radial velocity from ground-based telescopes.

Astrometry is the measurement of the positions and motions of celestial bodies. McArthur’s group used one of the Fine Guidance Sensors (FGSs) on the Hubble telescope for the task. The FGSs are so precise that they can measure the width of a quarter in Denver from the vantage point of Miami. It was this precision that was used to trace the star’s motion on the sky caused by its surrounding — and unseen — planets.

Radial velocity makes measurements of the star’s motion on the sky toward and away from Earth. These measurements were made over a period of 14 years using ground-based telescopes, including two at McDonald Observatory and others at Lick, Haute-Provence, and Whipple Observatories. The radial velocity provides a long baseline of foundation observations, which enabled the shorter duration, but more precise and complete, Hubble observations to better define the orbital motions.

The fact that the team determined the orbital inclinations of planets c and d allowed them to calculate the exact masses of the two planets. The new information told us that our view as to which planet is heavier has to be changed. Previous minimum masses for the planets given by radial velocity studies put the minimum mass for planet c at 2 Jupiters and for planet d at 4 Jupiters. The new, exact masses, found by astrometry are 14 Jupiters for planet c and 10 Jupiters for planet d.

“The Hubble data show that radial velocity isn’t the whole story,” Benedict said. “The fact that the planets actually flipped in mass was really cute.”

The fourth planet is so far out, that its signal does not reveal the curvature of its orbit.

The 14 years of radial velocity information compiled by the team uncovered hints that a fourth, long-period planet may orbit beyond the three now known. There are only hints about that planet because it’s so far out that the signal it creates does not yet reveal the curvature of an orbit. Another missing piece of the puzzle is the inclination of the innermost planet, b, which would require precision astrometry 1,000 times greater than Hubble’s, a goal attainable by a future space mission optimized for interferometry.

Sources: HubbleSite, AAS Press conference

Posted on by Nancy Atkinson

New Image Shows Phoenix Lander’s Solar Panel is Missing

wo images of the Phoenix Mars lander taken from Martian orbit in 2008 and 2010. The 2008 lander image shows two relatively blue spots on either side corresponding to the spacecraft's clean circular solar panels. In the 2010 image scientists see a dark shadow that could be the lander body and eastern solar panel, but no shadow from the western solar panel. Image credit: NASA/JPL-Caltech/University of Arizona

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The Phoenix lander will not be phoning home. A new image of Phoenix taken this month by the HiRISE camera (High Resolution Imaging Science Experiment) on board the Mars Reconnaissance Orbiter shows signs of severe ice damage to the lander’s solar panels, with one panel appearing to be completely gone. The Phoenix team says this is consistent with predictions of how Phoenix could be damaged by harsh winter conditions. It was anticipated that the weight of a carbon-dioxide ice buildup could bend or break the solar panels.

“Before and after images are dramatically different,” said Michael Mellon of the University of Colorado in Boulder, a science team member for both Phoenix and HiRISE. “The lander looks smaller, and only a portion of the difference can be explained by accumulation of dust on the lander, which makes its surfaces less distinguishable from surrounding ground.”

Mellon calculated hundreds of pounds of ice probably coated the lander in mid-winter. Several attempts to contact Phoenix during the past few months came up empty.

Phoenix parachute and backshell from 2008 (left) and 2010. Credit: NASA/JPL/U of Arizona

“We can see that the lander, heat shield, and backshell-plus-parachute are now covered by dust,” said Mellon and Alfred McEwen on the HiRISE website, “so they lack the distinctive colors of the hardware or the surfaces where the pre-landing dust was disturbed. But if the lander is structurally intact, it should cast the same shadows. While that is indeed the case for the shadow cast by the backshell (which came to rest on its side), that does not appear to be the case for the lander.”

See the larger image of all the various pieces of Phoenix on the HiRISE website.

So now, the Phoenix mission is officially over.

But during its mission on Mars, Phoenix confirmed and examined patches of the widespread deposits of underground water ice detected by Odyssey and identified a mineral called calcium carbonate that suggested occasional presence of thawed water. The lander also found soil chemistry with significant implications for life and observed falling snow. The mission’s biggest surprise was the discovery of perchlorate, an oxidizing chemical on Earth that is food for some microbes and potentially toxic for others.

“We found that the soil above the ice can act like a sponge, with perchlorate scavenging water from the atmosphere and holding on to it,” said Peter Smith, Phoenix principal investigator at the University of Arizona in Tucson. “You can have a thin film layer of water capable of being a habitable environment. A micro-world at the scale of grains of soil — that’s where the action is.”

The perchlorate results are shaping subsequent astrobiology research, as scientists investigate the implications of its antifreeze properties and potential use as an energy source by microbes. Discovery of the ice in the uppermost soil by Odyssey pointed the way for Phoenix. More recently, the Mars Reconnaissance Orbiter detected numerous ice deposits in middle latitudes at greater depth using radar and exposed on the surface by fresh impact craters.

“Ice-rich environments are an even bigger part of the planet than we thought,” Smith said. “Somewhere in that vast region there are going to be places that are more habitable than others.”

For more info and a look back at Phoenix, check out the Phoenix mission website.

Source: NASA

Posted on by Nancy Atkinson

WISE Covers the Heart and Soul of Infrared Astronomy

The Heart and Soul nebulae are seen in this infrared mosaic from WISE. Image credit: NASA/JPL-Caltech/UCLA

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In about six months’ time, NASA’s WISE mission, the Wide-field Infrared Survey Explorer, has captured almost a million images, covering about three-quarters, or 30,000 square degrees, of the sky. At the 216th American Astronomical Society meeting today, astronomers released a new mosaic of two bubbling clouds in space, known as the Heart and Soul nebulae.

“This image actually has two hearts; one is a Valentine’s Day heart, and the other is a surgical heart that you have in your body,” said Ned Wright of the University of California, Los Angeles who presented the new picture. “This new image demonstrates the power of WISE to capture vast regions. We’re looking north, south, east and west to map the whole sky.”

To make this huge mosaic WISE stared at this region of space which lies about 6,000 light-years away in the constellation Cassiopeia, for 3.5 hours of total exposure time, taking 1,147 images.

Both these nebulae are massive star-making factories, marked by giant bubbles blown into surrounding dust by radiation and winds from the stars. The infrared vision of WISE allows it to see into the cooler and dustier crevices of clouds like these, where gas and dust are just beginning to collect into new stars.

WISE will complete its first map of the sky in July 2010, and then spend the next three months surveying much of the sky a second time, before the solid-hydrogen coolant needed to chill its infrared detectors runs dry. Wright said the first installment of the public WISE catalog will be released in summer 2011.
Wright marveled at how in the span of his career he has gone from observing in just 4 pixels to now observing with WISE in almost 4 million pixels.

“It’s been an amazing progress in IR astronomy, with cameras growing by a factor of a million in power in just a few decades,” he said.

Screen shot from Wright's presentation at the AAS meeting showing how much of the sky WISE has covered. The small green box shows the area of the Heart and Soul nebulae.

Spotting NEO’s

One goal of the WISE mission is to study asteroids throughout our solar system and to find out more about how they vary in size and composition. Infrared helps with this task because it can get better size measurements of the space rocks than visible light.

So far, WISE has observed more than 60,000 asteroids, most of which lie in the main belt, orbiting between Mars and Jupiter. About 11,000 of these objects are newly discovered, and about 50 of them belong to a class of near-Earth objects, which have paths that take them within about 48 million kilometers (30 million miles) of Earth’s orbit.

“As WISE is orbiting the Earth, we are sweeping through the solar system like radar, and building up a map of what the solar system looks like in near infrared, looking for Near Earth Objects,” said astronomer Tommy Grav of Johns Hopkins University.

Grav told Universe Today so far there haven’t been any big surprises in the amount of NEOs the WISE team is finding. “We haven’t done full analysis of all the data WISE has sent back, but we’re finding about what we expected. We’re right in the ballpark of what we expected to find.”

The mission also studies the Trojans, asteroids that run along with Jupiter in its orbit around the sun in two packs — one in front of and one behind the gas giant. It has seen more than 800 of these objects, and by the end of the mission, should have observed about half of all 4,500 known Trojans. The results will address dueling theories about how the outer planets evolved.

“We can basically confirm and fill in the gap between ground based observations and the Spitzer Space Telescope’s observations of the Trojan asteroids,” Grav said.

Grav said WISE is an outstanding observatory. “We’ve basically done in six months what it took over 100 years to do in the optical.”

Sources: NASA, AAS press conference

Posted on by Steve Nerlich

Astronomy Without A Telescope – Stellar Quakes and Glitches

The upper crust of a neutron star is thought to be composed of crystallized iron, may have centimeter high mountains and experiences occasional ‘star quakes’ which may precede what is technically known as a glitch. These glitches and the subsequent post-glitch recovery period may offer some insight into the nature and behavior of the superfluid core of neutron stars.

The events leading up to a neutron star quake go something like this. All neutron stars tend to ‘spin down’ during their life cycle, as their magnetic field applies the brakes to the star’s spin. Magnetars, having particularly powerful magnetic fields, experience more powerful braking.

During this dynamic process, two conflicting forces operate on the geometry of the star. The very rapid spin tends to push out the star’s equator, making it an oblate spheroid. However, the star’s powerful gravity is also working to make the star conform to hydrostatic equilibrium (i.e. a sphere).

Thus, as the star spins down, its crust – which is reportedly 10 billion times the strength of steel – tends to buckle but not break. There may be a process like a tectonic shifting of crustal plates – which create ‘mountains’ only centimeters high, although from a base extending for several kilometres over the star’s surface. This buckling may relieve some of stresses the crust is experiencing – but, as the process continues, the tension builds up and up until it ‘gives’ suddenly.

The sudden collapse of a 10 centimeter high mountain on the surface of a neutron star is considered to be a possible candidate event for the generation of detectable  gravitational waves – although this is yet to be detected. But, even more dramatically, the quake event may be either coupled with – or perhaps even triggered by – a readjustment in the neutron’s stars magnetic field.

It may be that the tectonic shifting of crustal segments works to ‘wind ‘up’ the magnetic lines of force sticking out past the neutron star’s surface. Then, in a star quake event, there is a sudden and powerful energy release – which may be a result of the star’s magnetic field dropping to a lower energy level, as the star’s geometry readjusts itself. This energy release involves a huge flash of x and gamma rays.

In the case of a magnetar-type neutron star, this flash can outshine most other x-ray sources in the universe. Magnetar flashes also pump out substantial gamma rays – although these are referred to as soft gamma ray (SGR) emissions to distinguish them from more energetic gamma ray bursts (GRB) resulting from a range of other phenomena in the universe.

However, ‘soft’ is a bit of a misnomer as either burst type will kill you just as effectively if you are close enough. The magnetar SGR 1806-20 had one of largest (SGR) events on record in December 2004.

Along with the quake and the radiation burst, neutron stars may also experience a glitch – which is a sudden and temporary increase in the neutron star’s spin. This is partly a result of conservation of angular momentum as the star’s equator sucks itself in a bit (the old ‘skater pulls arms in’ analogy), but mathematical modeling suggests that this may not be sufficient to fully account for the temporary ‘spin up’ associated with a neutron star glitch.

Theoretical model of a neutron star's interior. An iron crystal core overlies a region of neutron-enriched atoms, below which is the degenerate matter of the core - where sub-atomic particles are stretched and twisted by magnetic and gravitational forces. Credit: Université Libre de Bruxelles (ULB).

González-Romero and Blázquez-Salcedo have proposed that an internal readjustment in the thermodynamics of the superfluid core may also play a role here, where the initial glitch heats the core and the post-glitch period involves the core and the crust achieving a new thermal equilibrium – at least until the next glitch.