Cassini Will Switch to Back-up Thrusters

Cassini Will Switch to Back-up Thrusters

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In a move reminiscent of Star Trek’s Scotty fine-tuning the Enterprise’s performance, engineers working with the Cassini spacecraft will begin work to switch the spacecraft’s thrusters to a back-up set after noticing a degradation in performance from the main thrusters that have been in use for over 11 years, since the spacecraft launched in October of 1997. The thrusters are used for making small corrections to the spacecraft’s course and for attitude control. In mid-March, the current set of eight thrusters, referred to as branch A, will be swapped over to a redundant and identical set, branch B. In a forward thinking move, almost all Cassini engineering subsystems have redundant backup capability. And in a testament of the spacecraft’s robustness and reliability, this is only the second time during Cassini’s 11-year flight that the engineering teams have gone to a backup system.

“Ay, Captain. Auxiliary thrusters engaged!”

Cassini’s propulsion engineers began to see a lower performance from one of the thrusters on branch A in October, and recently a second branch A thruster also began now showing some degraded performance.

An extensive review with the propulsion system contractor, Lockheed Martin Space Systems, Denver, Colo., the thruster manufacturer, Aerojet, Sacramento, Calif., and propulsion experts at NASA’s Jet Propulsion Laboratory, Pasadena, Calif., was completed last week. The recommendation was made to swap to side B as soon as is practical.

Nine of Saturn's moons are in this image.  Can you find them? Credit: NASA/JPL/Space Science Institute
Nine of Saturn's moons are in this image. Can you find them? Credit: NASA/JPL/Space Science Institute


Mid-March is the earliest practical opportunity to make the swap. This allows time for the team to properly test and prepare the sequence of commands that will be sent to the spacecraft. Science planners have identified a period where no high-priority science will be lost during the switch, which will be done over a seven-day window. It also is a time when no navigation maneuvers are required to maintain the spacecraft’s trajectory.

The swap involves commanding a latch valve to open hydrazine flow to the B side, and powering on some thruster control electronics. No pyrotechnic devices are involved in the swap, and the action is fully reversible if necessary.

A few years ago, the backup reaction wheel was brought online and is currently functioning as one of the three prime wheels.

Cassini successfully completed its four-year planned tour and is now in its “Equinox” extended mission operations.

Source: JPL

Google Oceans, Google Mars

The Mars feature of Google Earth 5.0 lets users see the Red Planet from the perspective of Rovers like the NASA Mars Pathfinder Rover. (Credit: NASA/Google/JPL/University of Arizona)

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Google Earth now allows you to probe the depths of Earth’s oceans as well as fly through the giant canyons or volcanoes on Mars. Google Earth 5.0 was unveiled today, with substantial upgrades for both the Earth and the Red Planet. Google worked in conjunction with NOAA and NASA to incorporate data from our undersea explorations and the spacecraft orbiting Mars. For the first time, you’ll be able to look at the two-thirds of our planet covered by the oceans, take a tour below sea level, and even look at historical imagery to see things like coastal erosion. On Mars there’s a rich conglomeration of images, including the most recent from the Mars Reconnaissance Orbiter to provide an immersive 3D view of Mars. Marine scientists say the electronic images will boost awareness and increase public support for marine conservation, while NASA says the new features in Google Mars will aid public understanding of Mars science, while also providing researchers a platform for sharing data similar to what Google Earth provides for Earth scientists.

In Google Oceans, you can click a function called Touring and you can create narrated, illustrated tours, on land or above and below the sea surface, describing and showing things like a hike or scuba excursion, or even a research cruise on a deep-diving submarine.

A view of the coast of Maui, outside Lanai City, Hawaii, from the new version of Google Earth.
A view of the coast of Maui, outside Lanai City, Hawaii, from the new version of Google Earth.

By choosing among 20 buttons holding archives of information, called “layers” by Google, a visitor can read logs of oceanographic expeditions, see old film clips from the heyday of Jacques-Yves Cousteau and check daily Navy maps of sea temperatures.

While only 5% of the ocean floor is mapped in detail, the replicated seas have detailed topography reflecting what is known about the abyss and continental shelves with rougher areas where little is known.

On Mars, you can enjoy a high-resolution, three-dimensional view of the Red Planet.

There is a mode that enables users to fly virtually through enormous canyons and scale huge mountains on Mars that are much larger than any found on Earth. Users also can explore the Red Planet through the eyes of the Mars rovers and other Mars missions, providing a unique perspective of the entire planet.

Clickable links allow you to learn about new discoveries and explore indexes of available Mars imagery. If you’re into working with the raw images from the Mars rovers or orbiting spacecraft, the new Mars mode also allows users to add their own 3D content to the Mars map to share with the world.

Since 2005, Google Earth has been downloaded on half a billion computers, and visitors spend one million hours a day perusing Google Earth and the related Google Maps.

Guess what I’ll be doing the next few hours!

Download Google Earth 5.0.

Sources: NASA, New York Times

Volans

Volans

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The southern circumpolar constellation of Volans was first introduced in 1589 by Petrus Plancius on a celestial globe which was later added to Johann Bayer’s atlas – Uranometria – in 1603. Volans spans 141 square degrees of sky, ranking 76th in size. It has 6 mains stars in its asterism and 12 Bayer Flamsteed designated stars within its confines. Volans is bordered by the constellation of Carina, Pictor, Dorado, Mensa and Chamaeleon and is best seen at culmination during the month of March.

Since Volans is considered a “new” constellation, it has no mythology associated with it – only what the constellation is meant to represent. The constellation of Volans was originally created by Petrus Plancius from the stellar observations of Dutch sea navigators Pieter Dirkszoon Keyser and Frederick de Houtman when exploring the southern hemisphere. Volans’ stellar patterns became known when it appeared on a celestial globe in 1597 and was considered a constellation when it was added to Johann Bayer’s Uranometria catalog in 1603 and it was then called Piscis Volans – the “Flying Fish”. When it was later adopted as a permanent constellation by the International Astronomical Union, the name was simplified and shortened to just Volans.

Let’s begin our binocular tour of Volans with its Alpha star – the “a” symbol on our chart. Alpha Volantis is located approximately 124 light years from Earth and it is a white class A (A2.5) subgiant star. While it is not anything particularly special, it is about twice the size of our Sun and shines about 30 times brighter. Somehow it got the Alpha designation, even though Beta (the “B” symbol) is physically brighter and 16 light years closer! Want a real trip? Then have a look at Delta – the “8” symbol. Even though it appears almost as bright as the rest of the stars, Delta is an F-type bright giant star that’s 660 light years from our solar system!

Now, get out your telescope for Epsilon Volantis – the backwards “3”. Epsilon is a triple star system! Located approximately 642 light years from Earth, the primary component, Epsilon Volantis A, is a spectroscopic binary star all of its own. It’s a blue-white B-type subgiant star with a companion that orbits so close we can only see it spectroscopically and know that it causes changes about every two weeks. But take a close look and you’ll discover a third, 8th magnitude star there, too. Epsilon Volantis B is 6.05 arcseconds away and an easy capture for a small telescope and large binoculars.

How about Gamma Volantis? It’s the “Y” symbol. This wide double star was just meant for binoculars! The two members are brighter, western Gamma-1 Volantis (magnitude 5.67) and dimmer, eastern Gamma-2 (magnitude 3.78). Set apart by 14.1 seconds of arc, you won’t have any trouble cutting these two stars apart and their color contrast make them a real winner in a telescope. Gamma-2 is a standard orange class K (K0) giant star and Gamma-1 is a a white class F (F2) dwarf star. While you might think this is an optical double star, it isn’t. The pair is physically bound to each other and both stars are about 142 light years away.

For those wishing a challenge, take on about the only deep sky study to be found in Volans – NGC 2442 (RA 7 : 36.4 Dec -69 : 32). At 11th magnitude and 6 arc minutes in size, this low surface brightness barred spiral galaxy is a nice study for a large telescope. Located about 50 million light years away from our Milky Way Galaxy, NGC 2442 was first was discovered by Sir John Herschel and contains a very unusual dark cloud of gas – one devoid of any stars. How did this come to be? Astronomers believe the cloud was torn loose from NGC 2442 by a companion during a galaxy interaction. Why not? After all, NGC is surrounded! If you have large aperture, you’ll see PGC 21457, PGC 21406, NGC 2434, PGC 21212, PGC 21323, PGC 21369 and PGC 21426 are nearby, too. Several of these satellite galaxies are physically related to NGC 2442. Be sure to look for two spiral arms extending from a pronounced central bar, giving the whole galaxy a hook-shaped appearance.

Sources:
Wikipedia
University of Wisconsin
Chart Courtesy of Your Sky.

Journey Inside A Bok Globule

NGC281/IC1590 Parallel Vision - Jukka Metsavainio

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You asked for more? You got it. This time our dimensional visualization is going to take us 9500 light years away from where you’re sitting now and deep into the Perseus spiral arm of the Milky Way Galaxy. Buckle your seat belt and relax your eyes, because we’re heading into two versions of a 132 light year expanse known as NGC 281 and the central core called IC 1590…

Just like last time, this dual image requires a little bit of a challenge on your part to create a 3D effect. Thanks to the wizardry of Jukka Metsavainio, we’ve gone even one better. There’s two! The first version you see on this page are for those of you who have success relaxing your eyes and being a certain distance from the screen to get the images to merge. The one below is for those of you who have better luck crossing your eyes and catching dimension in the center image. Are you ready for your journey? Then have a look and let’s learn…

NGC281/IC1590 Hubble Heritage Cross Vision - Jukka Metsavainio
NGC281/IC1590 Hubble Heritage Cross Vision - Jukka Metsavainio

The whole gigantic region of nebulosity is known as NGC 281 and most commonly referred to as the “Pac Man Nebula”. Visible to small telescopes and located in the constellation of Cassiopeia (RA 00:42:59.35 Dec +56:37.18.8), this cloud of high density hydrogen gas is being ionized by an incredible output of ultraviolet radiation from the hot, neophyte stars which coalesced there. Deep in the center of this HII region is a open area called IC 1590 – home to a young galactic star cluster – and several dark patches known as “Bok Globules”.

If that sounds like something you might expel when you have a cold, you’re right. They are cold… Cold pockets of dense dust, molecular hydrogen and gas. Bok globules are the brain child of astronomer Dr. Bart Jan Bok – who, among other things, loved to study the paranormal. When Bok proposed their existence in the 1940’s, he knew what was going on. These dark regions were acting like interstellar cocoons – protecting their inner stars from being stripped by the radioactive stellar winds of nearby companions and blocking visible light. When stellar metamorphosis had occurred, the new star then begins to send out its own winds and radiation to evaporate the globule – but this isn’t always the case. Sometimes the cocoon gets destroyed before the life inside ignites.

In our image you will see bright blue stars, members of the young open cluster IC 1590, near the globules. Meanwhile, the cluster’s partially revealed core in the upper right hand corner is filled with a tight grouping of extremely hot, massive stars emitting visible and ultraviolet light, causing those incredible pink clouds. When these star forming dust clouds were first imaged by Hubble, we thought we knew a lot about them. But what have we learned since?

According to research done by T.H. Henning (et al): “The exciting star HD 5005 of the optical nebulosity is a Trapezium system… and emission shows that the molecular cloud NGC 281 A consists of two cloud fragments. The western fragment is more compact and massive than the eastern fragment and contains an NH3 core. This core is associated with the IRAS source 00494+5617, an H2O maser, and 1.3 millimeter dust continuum radiation. Both cloud fragments contain altogether 22 IRAS point sources which mostly share the properties of young stellar objects. The maxima of the 60 and 100 micrometers HIRES maps correspond to the maxima of the (12)CO (3 to 2) emission. The NGC 281 A region shares many properties with the Orion Trapezium-BN/KL region the main differences being a larger separation between the cluster centroid and the new site of star formation as well as a lower mass and luminosity of the molecular cloud and the infrared cluster.”

Great! It’s confirmed! It’s a star forming region, very much like what we can observe when we see M42. But, maybe… Maybe there’s just a little bit more to it than that? Hubble observations shows the jagged structure of the dust clouds as if they are being stripped apart from the outside. What could have caused that? Only the radiation from the nearby stars? Hmmm…. Not everyone seems to think so.

A 2007 study done by Mayumi Sato (et al) states: “Our new results provide the most direct evidence that the gas in the NGC 281 region was blown out from the Galactic plane, most likely in a superbubble driven by multiple or sequential supernova explosions in the Galactic plane.” Supernova? Yeah, you bet. And someone else thinks so, too…

Says S.T. Megeath (et al): “We suggest that the ring has formed in a superbubble blowout driven by OB stars in the plane of the Galaxy. Within the cloud complex, combined optical, NIR, mm and cm data detailing the interaction of a young O star with neighboring molecular cores, provide evidence of triggered star formation inside the cloud complex on a few parsec scale. These data suggest that two modes of triggered star formation are operating in the NGC 281 complex – the initial supernovae triggered formation of the entire complex and, after the first generation of O stars formed, the subsequent triggering of star formation by photoevaporation-driven molecular core compression.”

You’ve got it. This type of research suggests the cores were created within the molecular cloud. When they were exposed to direct UV radiation, the low density gas was stripped. This increase in pressure then caused a rippling shockwave which triggered star formation – first in the compressed regions and then in the HII areas. Says Megeath, “The total kinetic energy of the ring requires the energy of multiple supernovae. Both the high Galactic latitude and large expansion velocity may be explained if the NGC 281 complex originated in the blowout of an expanding superbubble. The loop of HI seen extending from the Galactic plane may trace the edge of a superbubble powered by supernovae near the Galactic plane. The expansion of a superbubble into the increasingly rarefied Galactic atmosphere can lead to a runaway expansion of the shell and the blowout of the bubble into the Galactic atmosphere. NGC 281 could have formed in the gas swept up and compressed in a blowout. Hence, NGC 281 maybe an example of the supernovae-driven formation of molecular clouds (and consequently, supernovae-triggered star formation).”

What incredible region! Hope you enjoyed your journey… And be sure to tip your hat to Bart Jan Bok who told the IAU (when they named Asteroid Bok for him in 1983) “Thanks for a little plot of land that I can retire to and live on.”

Our many, many thanks to Jukka Metsavainio of Northern Galactic for creating this unique image for Universe Today Readers! We look forward to more…

Super Bowl Goes to Space

I admit, I watched the Super Bowl with all its hype and consumerism. But who can pass up a good excuse for a party or miss a chance to see Springsteen? A couple of the advertisements caught my eye. One was a fun spot with astronauts tearing around on Titan with a space-age hot rod. The premise is old, but enjoyable nonetheless. If you didn’t get a chance to see it, here it is:

Also, a trailer for the new Star Trek movie aired during the game, with more hot rods:
Continue reading “Super Bowl Goes to Space”

Comet C/2007 N3 Lulin – A Twist In The Tail

Comet C/2007 N3 Lulin - J. Brimacombe

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When Chi-Sheng Lin of Taiwan’s Institute of Astronomy captured three images on July 11, 2007 with something strange in them, it was first believed he’d picked up just another asteroid. But, by July 17 astronomers in Table Mountain Observatory, California were noticing a coma 2-3″ across, with a bright central core. That’s not an asteroid… That’s a comet! And now it’s a comet that’s doing something very strange…

By the end of 2008, Comet C/2007 N3 Lulin had steadily began to brighten and now is within easy reach of binoculars for all observers. How bright is it? At last estimate it is between magnitude 6 and 7. That means just a little too faint to be seen unaided, but bright enough to be spotted easily with just the slightest of visual aids. Our own Nancy A. did an article on this not long ago!

But there’s something going on with N3 Lulin, right now… Something very different. There’s a twist in the tail! Check this out…

Comet C/2007 N3 Lulin (negative luminance) - J. Brimacombe
Comet C/2007 N3 Lulin (negative luminance) - J. Brimacombe

While imaging N3 Lulin for UT Readers, Dr. Joe Brimacombe used a negative luminance frame to take a closer look at what’s going on and discovered something quite out of the ordinary. First off, you’ll notice an anti-tail – quite rare in itself – but if you take a look about halfway down the ion/dust tail, you’ll see a very definite twist in the structure. It it rotating? Exactly what’s causing it? Torsional stress? Is it possible that the kink in the tail is an instability resulting from currents flowing along the tail axis? Right now there’s absolutely no information available about what’s going on in the tail – because what you’re seeing is perhaps one of the most current pictures of the comet that can be found!

Chart Courtesy Heaven's Above
Chart Courtesy Heaven's Above
If you’re interested in viewing Comet C/2007 N3 Lulin for yourself and would like some help locating it, there’s a wonderful resource that’s easy to use. Just go to Chris Peet’s Heaven’s Above website and make use of the tools there. It will give you easy to follow charts and all you need is just a pair of binoculars to spot this comet for yourself. Don’t sit inside… Do it!

My sincere thanks to Dr. Joseph Brimacombe of Northern Galactic for not only his superb imaging – but his sublime sense of curiosity which caught this anomaly!

R Coronae Borealis At Faintest

R Coronae Borealis Field - J. Brimacombe

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For those of you who like observing curiosities, it’s time to take a look at R Coronae Borealis. As you may have guessed from the single letter designation, R is a variable star, but it’s not just any old variable – it’s the prototype of its class. What exactly is an R CorBor star, what does it do and why is taking the time to check it out now so important? Then step inside and find out…

R Coronae Borealis stars (RCB) type stars are one of the oldest known classes of variable star. In just a period of a few weeks, they can drop in brightness by factors of thousands and what they do is totally unpredictable. Within months, they recover again to their maximum brightness… But why? While astronomers don’t fully understand the evolutionary origin and the physical mechanism behind what drives R CorBor types, they do know the stars pulsate – generating a sort of sooty dust cloud just above the surface. Like an old-fashioned oil lamp with its wick turned up too high, when R Cororonae Borealis stars burn their fuel, they smoke up their exterior – just like the lamp smokes its glass chimney and dims the light. What remains on the glass? That’s right. Carbon. And the surfaces of RCB stars are unusually poor in hydrogen, and rich in carbon and nitrogen. Chances are very good that R CorBor stars are actually the remnants of more fully evolved stars.

Just a few days ago, M. Templeton of the American Association of Variable Star Observers (AAVSO) released Special Notice #145:

“R Coronae Borealis, the prototype of the R CrB class, is apparently at or near historic minimum; a number of observers have put this star below m(vis)=14.0 since early November 2008, and both visual and instrumental measures are now indicating R CrB is near or below V=14.5. R CrB began its current fading episode around JD 2454288 (2007 July 6 +/- 1 day), and faded from m(vis) ~ 6.0 to below m(vis) ~ 12.0 by JD 2454325 (2007 August 12). The star has continued to fade for the past 17 months. Current visual observations by a number of AAVSO visual observers estimate the star to be around m(vis) 14.3-14.5, and V-band CCD observations suggest the star may be at or near V=15.0. BAAVSS observer J. Toone also visually estimated the star is at m(vis) ~ 14.9 (via baavss-alert). Both visual estimates and instrumental photometry of R CrB are strongly encouraged at this time.

The duration of the current episode and its depth are similar to that observed during the previous extreme fading episode which began circa JD 2438200 (June 1963) and continued with only one brief interruption until circa JD 2439100 (December 1965). During the 1963-1965 event, a few AAVSO observers estimated that R CrB reached m(vis) around 14.9-15.0, although the average visual estimate remained around 14.2-14.3 at minimum. The current episode seems to have reached the same depth; there is no way to tell whether the fade will continue, although the light curve has been flat or trending weakly downward for several months. As J. Toone pointed out, the current magnitude is very close to if not fainter than the historic minimum for this star.”

Of course, nearing magnitude 15 isn’t within the territory of binoculars or small telescopes – but it is within the grasp of many of our amateur astronomer UT readers with larger equipment, clear skies and the willingness to seize the opportunity to record this historic astronomical event. (I dislike the term “amateur” – it only means you don’t get paid for it, folks… Not that you’re any less serious or talented!) One such astronomer is Dr. Joseph Brimacombe, who took up the gauntlet immediately. Although Joe hails from Australia where R Coronae Borealis isn’t visible, today’s astronomy world is far different than it used to be. Thanks to the magic of the Internet, he immediately set about the task of capturing the star on January 30, 2009 via a robotic telescope located in New Mexico and shared his results with us.

R Coronae Borealis True Color - J. Brimacombe
R Coronae Borealis True Color - J. Brimacombe

R CrB Chart - AAVSO
R CrB Chart - AAVSO
For those wishing to also participate in the quest for R Coronae Borealis, you’ll find it located at the following (J2000) coordinates: RA: 15 48 34.40 , Dec: +28 09 24.0 and you may use this field chart provided by the AAVSO to further refine your observations. If R is too faint for your equipment now? Don’t worry. It’s a variable star and within a few months it will return to its easily spotted magnitude 6 self – and a very delightful red star in binoculars. As always, be kind to science and contribute! Please promptly submit all observations to the AAVSO using the name “R CRB” and take part in astronomy history!

My many thanks to Joe Brimacombe of Northern Galactic for his superb talents and to the AAVSO for keeping us on alert!

Russia Wants to Build New Space Station, Extend Life of ISS to 2020

The Mir space station hangs above the Earth in 1995 (photo by Atlantis STS-71, NASA)

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The Russian space agency (Roscosmos) has announced that it will lobby Moscow with a proposal that would see the construction of a new Russian space station in low-Earth orbit. Also, the agency has expressed a desire to extend the operational lifespan of the International Space Station (ISS) until 2020 (the outpost is set for retirement in 2015). Building a Russian space station will aid Russia’s desire to kick-start their lunar program, possibly acting as a staging post for future missions to Mars…

The ISS has been a hot topic over the last few months, but not always for the right reasons. Its construction is behind schedule by at least five years, primarily due to the Columbia disaster in early 2003 plus some funding problems in the Russian space agency. However, despite its problems, the ISS was 76% complete as of July 2008 and it is set for completion in 2010. This may be the case, but the station is scheduled to be retired in 2015, meaning science on the completed ISS only has a period of five years before it is de-orbited and sent the same way as Mir in 2001 (i.e. down).

Could the ISS be modified to travel to Mar<span>s</span>? Credit: NASA/Ian O'Neill
The thought of disposing of the ISS so soon has led to some speculative “alternative uses” for the ISS; one of the most outlandish being the conversion of the ISS into some kind of International Space Ship, retrofitting the station with rockets and sending it to the Moon and/or Mars to act as a manned mothership for planetary activities. Although this excites my science fiction imagination, this possibility seems unlikely (it would be cool though…).

It seems that Roscosmos has made their feelings clear about the whole situation, making an announcement on Thursday wanting to drum up support for an ISS extension to 2020 and start the construction of a Russian replacement space station, forming the back bone of Roscosmos’ ambitions to set up a base on the Moon and then make a manned expedition to the Red Planet.

We will soon propose to our government a project to construct a low-orbit complex, which could serve as a foundation for the implementation of the lunar program and later on – the Mars program,” Alexei Krasnov, director of manned flight programs at Roscosmos, said in a news conference in Moscow on January 29th. “These are our intentions, but we are working hard to ensure that these plans get adequate financial and legislative support from the government.”

The Russian space agency has often been criticised for having ambitions exceeding their budgets, but this is an interesting proposition. The biggest obstacle (apart from the funding bit) would be to convince the other ISS member states to continue funding the mission. “We are considering the extension of ISS service life at least until 2020, but this decision must be adopted by the governments of all 15 countries participating in the project,” Krasnov said.

The idea of having a Russian space station is not very hard to imagine, after all, Roscosmos has the experience of designing, constructing and living on the Mir space station (with the assistance of the Shuttle-Mir Program intended to forge a collaboration between the US and Russia in the run-up to “Phase 2” of the space relationship: constructing the ISS), and they have a very robust existing launch system. All this will be a valuable infrastructure toward supporting the construction of a new manned outpost.

Although this announcement sounds very exciting for Russia, the space agency is beset with financial woes of its own; the idea of embarking on an expensive space station project probably wont be entertained for very long…

Source: RIA Novosti

China Building Huge 500-Meter Radio Telescope

Artist concept of the FAST Telescope. Credt: Physicsworld.com

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Official ground-breaking ceremonies took place for a gigantic new 500 meter diameter radio telescope in China which will allow astronomers to detect galaxies and pulsars at unprecedented distances. The $102 million facility, known as the Five-hundred-meter Aperture Spherical Telescope (FAST), will have a collecting area more than twice as big as the 305 meter diameter radio telescope at Arecibo Observatory in Puerto Rico, which has been the world’s largest since it opened in 1964. Not only that, the new telescope will also have the ability to change its shape and move the position its focus.

Like the Arecibo telescope, the new telescope will sit in a natural depression that already is close to the shape of the collecting surface, simplifying the support structure and shielding the telescope from stray human-generated radio waves. The location is quite remote, about 170 km by road from the Guizhou Province’s provincial capital Guiyang, making it unusually radio-quiet, says Nan Rendong, FAST chief scientist and a researcher from the National Astronomical Observatories at the Chinese Academy of Sciences, in an article in Physicsworld.com.

The site’s potential for long, uninterrupted observations — coupled with the telescope’s huge size, which will give it twice the sensitivity of Arecibo — means that researchers there will be able to detect objects like weak, fast-period pulsars that are too faint to be measured accurately by smaller instruments.

Groundbreaking ceremonies for FAST. Credit: Physicsworld.com
Groundbreaking ceremonies for FAST. Credit: Physicsworld.com

“The FAST science impact on astronomy will be extraordinary,” Nan said, adding that although the telescope is located in China, once it is completed in 2014 it will be open to astronomers from around the world.

A system of motors attached to its 4600 panels will allow astronomers to change its shape from a sphere to a paraboloid, making it easier to move the position of the telescope’s focus. This will allow the south-pointing telescope to cover a broad swathe of the sky — up to 40 degrees from its zenith, compared to the 20-degree-wide strip covered by Arecibo.

At first, however, the telescope will only be sensitive to low-frequency radio waves, less than 3 GHz. Arecibo’s bandwidth, by contrast, stretches up to 10 GHz.

A planned second phase of construction will extend FAST’s range to 5 GHz, but a date for the upgrade has not yet been set.

Source: Physicsworld.com

Ares I-X 2009 Test Flight Progress: Pyrotechnic Stage Separation

A full-scale separation test of the forward skirt extension for the Ares I-X flight test at its facility in Utah (NASA/ATK)

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The successful test of NASA’s Ares I-X Forward Skirt Extension on Thursday represents a “major milestone” in the development of the launch system, according to Alliant Techsystems (ATK). The “skirt extension” in question is a solid ring of aluminium (or aluminum) connecting the first stage with the upper stages of the rocket.

This summer, the first flight of the Constellation Program is scheduled to blast off from a Cape Canaveral launch pad. The ATK pyrotechnics deep in the Utah Desert has proven to NASA that a key portion of this test flight will go as planned, allowing the reusable portion of the Ares I to return to Earth for recovery…

To say 2008 was a turbulent year for the Constellation program is an understatement. Although there have been a number of successful tests (including the test firing of the jettison motor, launch abort system and an old Shuttle engine; plus parachute tests), political tensions, criticism of the technology and budget uncertainty have all taken their toll. The future of the Constellation Program is in doubt (or shaky at best) and there’s not many media headlines with anything positive to say. So, when there is a successful test of any Ares component, it is certainly worth reporting, in an attempt to redress the good-news/bad-news balance and give credit where credit is due.

Artist impression of the Ares I-X at the launchpad, plus labelled sections of the rocket (NASA)
Artist impression of the Ares I-X at the launchpad, plus labelled sections of the rocket (NASA)
So, last week, ATK successfully tested the explosive charges that will perform the most important task of the test launch of the Ares I-X. The Forward Skirt Extension is located between the first and second stages of the rocket (pictured left). This 1.8 metre (6 ft) long by 3.7 metre (12 ft) diameter aluminium cylinder will allow the first stage booster to separate at the frustum (a cone-shaped connector that attaches the first stage to the larger diameter upper stage). During the launch, separation will occur at an altitude of around 40 km (130,000 ft).

This section will also be important as it will need to store the recovery parachutes for the first stage and it will need to support the mass of the upper stages (plus payload) during launch. It is for this reason that the skirt is forged from one solid lump of aluminium and reinforced with a unique internal support structure, housing three main parachutes.

Data from the charge detonation will be used to measure the shock generated, understanding how this might affect the Ares I-X mission and future Ares I launches. Thursday’s test appears to have achieved this as well as severing the forward skirt extension.

Roll on summer, I’m looking forward to seeing the Ares X-I first stage parachute to Earth

Source: NASA