Podcaster: Morgan Rehnberg
Link : http://cosmicchatter.org
Flying Saucer: http://www.space.com/26383-nasa-flying-saucer-test-ldsd.html
New Horizons: http://www.nature.com/news/pluto-bound-probe-faces-crisis-1.15261
Description: In this episode of the Monthly News Roundup, we celebrate one telescope’s birthday while its successor is selected and its sister turned to a new task. NASA tests new equipment and a famous man laughs when you’d least expect it.
Bio: Morgan Rehnberg is a graduate student in astrophysics and planetary science at the University of Colorado – Boulder. When not studying the rings of Saturn, he develops software to help search for asteroids that might hit the Earth. He blogs and podcasts about astronomy and space science at http://cosmicchatter.org.
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You’re listening to the 365 Days of Astronomy podcast for July 31st, 2014. I’m Morgan Rehnberg and this is the Monthly News Roundup. This episode was produced by Cosmic Chatter and recorded July 27th from Boulder, Colorado.
Let’s start this month by wishing the Chandra X-ray Observatory a happy birthday. Fifteen years ago, this July, Chandra was launched aboard the Space Shuttle Columbia as the third installment of NASA’s Great Observatories program. Eclipsed in the limelight by its older sister Hubble, Chandra has nonetheless been instrumental in advancing our understanding of the Universe.
The cosmos as revealed by Chandra is a beast dramatically different than that observed by Hubble. Visible light, emitted by stars like the Sun and seen through our eyes and the mirrors of traditional telescopes, basically illuminates nature going about its day-to-day business. On the other hand, X-rays, far more energetic than normal light, are created by the Universe’s most extreme objects and violent events.
Named after Indian-American Nobel laureate Subrahmanyan Chandrasekhar, the telescope orbits far above the X-ray absorbing atmosphere of the Earth. Because matter absorbs X-rays efficiently, Chandra is built using a series of special, highly angled reflecting surfaces. As the X-rays enter the telescope, they graze off these surfaces and bounce into the detectors. With this design the observatory boasts more than a thousand times the resolution of the first orbiting X-ray telescope. It came at a price, though: Chanda cost more than one and a half billion dollars and represented the largest ever satellite carried by the Space Shuttle.
The sorts of things observed by Chandra are the stuff of sensational headlines and dramatic imagery. Among the most important have been studies of our galaxy’s supermassive black hole, enormous supernova shock waves, and the collisions of galaxies. The telescope has even probed the boundaries of cosmology, estimating the rate of expansion of our Universe and placing new limits on the properties of the mysterious Dark Matter.
Like many NASA missions before it, Chandra has greatly outlived its planned mission lifetime. When first launched in 1999, a five-year mission was planned. After a further ten years of operation, Chandra still seems fit to continue for another decade yet.
While Chandra may have already lived three times its design lifetime, it may need to soldier on another fifteen years. Earlier this month, ESA, the European Space Agency, selected an X-ray telescope as its next large project. The catch for researchers? Its earliest launch date in 2028!
The advanced telescope for high-energy astrophysics, or Athena, will offer a dramatic leap in observing power over current-generation X-ray telescopes. ESA plans to utilize this power to answer questions about the early Universe. How did the uniform distribution of matter transform into the large-scale structure we see today, and how did the earliest generation of black holes affect the material around them?
Scientists now think that the Universe as we know it began approximately 13.8 billion years ago with the Big Bang. In mere instants, virtually all the matter in the Universe was created, arranged nearly identically across all of space. Today, that matter has coalesced into the stars and galaxies which dot the cosmos. Simulations suggest that in between these stages, the gas and dust of the Universe collapsed into the long, spindly arms of a web-like structure. Exactly how this collapse occured is still not well understood.
Another curiosity of the Universe today is that nearly all galaxies have been observed to host a giant supermassive black hole at their center. In addition, none of these enormous black holes have been seen on their own, outside of galaxies. There are two basic theories for why this might be. EIther large black holes act as the seeds which begin galaxies, or the collision of normally-sized black holes within galaxies lead to their growth into supermassive status. By watching as superheated material falls into the clutches of these beats, Athena hopes to shed light on this relationship.
Fourteen years may seem like a long time from now, but that’s actually pretty typical for developments in astronomy. It also took fourteen years to design and build Chandra, and the James Webb Space Telescope, successor to Hubble, has been in development now for more than a decade. But, it’s this deliberate methodology and careful attention to detail that has allowed spacecraft like Cassini, Chandra, and Opportunity to astonish us with their longevity.
Two years ago, next month, NASA undertook the most dramatic landing since astronauts first touched down on the Moon. After hurtling through the Martian atmosphere, a rocket-powered platform dubbed the sky crane carefully lowered the Mars Science Laboratory Curiosity to the surface of the Red Planet. Weighing in at a cool one ton, the car-sized rover became the heaviest object to ever land on Mars. The sky crane captured the world’s attention, but if we want to land even larger payloads on our sister world, we’re going to have to be even bolder.
The problem lies with Mars’ atmosphere. Merely one percent as dense as Earth’s, it simply cannot slow down the larger ships used to transport people and equipment back and forth from Earth orbit. But, it’s impractical to use rockets alone to slow a craft from interplanetary speed to a safe landing velocity. The fuel requirements would simply be too high.
NASA hopes its Low-Density Supersonic Decelerator can be the solution we need. It comes in two parts. FIrst is a giant parachute, more than thirty meters, or a hundred feet, in diameter. This attaches to the Supersonic Inflatable Aerodynamic Decelerator, or SIAD. You can think of a SIAD, which comes in six- or eight-meter variants, as like a giant blow-up child’s pool turned upside down. As it plunges through the Martian atmosphere, it inflates and traps air beneath it. As air collects on the underside, it becomes denser and can support more weight.
Another challenge when developing new landing technologies is finding an adequate way to test them, given the vast atmospheric differences between Earth and Mars. Sometimes it simply isn’t possible. The sky crane, for example, couldn’t be tested in its completed form before blasting off to Mars. This month, however, NASA took a crack at testing its new idea, dubbed the Flying Saucer.
A giant balloon carried a simulated test payload attached to the Low-Density Supersonic Decelerator high into the sky above the Pacific Ocean near Hawaii. There, a rocket carried the setup even farther up, about halfway to the edge of space. As altitude increases, the Earth’s atmosphere thins dramatically. By boosting their test vehicle up this high, NASA put it in a region of the atmosphere about one percent as dense as at sea-level – perfect conditions for replicating Mars.
Ultimately, the test proved only partially successful. The pool-shaped LIAD seems to have inflated correctly, slowing the payload to the still-blistering speed of Mach 2.5, at which the parachute can be safely opened to further reduce the rate of descent. Unfortunately, the parachute failed to open and the craft slammed into the ocean at a high rate of speed.
Despite this failure, flight engineers monitoring the test were thrilled with the results. A recovery ship was able to pick up the flying saucer and its valuable flight data recorders. Engineers will now analyze the data contained within to better understand what went right and wrong on this first attempt.
One thing is clear: if we’re going to put humans on Mars, we’re going to need a lot of equipment to do it. Our future deliveries to the Red Planet will be bigger and bulkier than ever before. We’re faced with a challenging engineering problem, but it’s one that we will overcome. And when we do, science and exploration in the solar system will never be the same again.
Monday, July 14th marked Bastille Day in France. As millions celebrated the 225th anniversary of the start of the French Revolution, the New Horizons spacecraft was also marking a major milestone on its lonely journey to the dwarf planet Pluto. It’s now less than one year before the ship makes its closest approach to this enigmatic object. While a year might seem like a long time to go, New Horizons has already been travelling more than eight and a half times that long. And, an even more pressing deadline is rapidly approaching.
In order to reach Pluto in a reasonable amount of time, New Horizons is travelling extremely quickly. So quickly, in fact, that, given Pluto’s small mass, it will be impossible for the spacecraft to slow down and enter orbit. Instead, the probe will blast between Pluto and Charon and head towards the outer reaches of the solar system. After the flyby occurs, mission controllers hope New Horizons will be able to continue on to an even-more-distant body within the Kuiper Belt. There’s only one problem: we haven’t found one for it to visit yet
The root of the issue is that New Horizons carries very little fuel on board. This makes it light and able to travel quickly, but it reduces the amount of maneuvering possible. In order to visit a Kuiper Belt object, the spacecraft will need to fire its engines next fall to redirect it onto an intercepting course. But only a small region of space is reachable and, so far, none of the thousand-plus objects we’ve discovered lie within reach. We’ve turned some of the world’s largest telescopes towards Pluto to aid in the search, but astronomers have decided its time to bring in the biggest gun of them all: Hubble.
After carrying out a successful proof-of-concept test in another region of the sky, researchers have shown that Hubble is capable of finding objects for New Horizons to visit. The telescope will spend much of August searching, but time is running out. In order to give mission controllers enough time to compute the necessary trajectory, an object must be discovered by early autumn. In a sense, Hubble is our last real chance at completing this part of the mission.
If an object is indeed found, it will likely take New Horizons several additional years to reach it after passing Pluto. And if our search comes up empty, the mission will still shed a tremendous amount of light, so to speak, on the nature of this distant class of object.
Finally this month, the forty-fifth anniversary of mankind’s first steps on the Moon. It was July 20th, 1969 when Neil Armstrong hopped off the Lunar Module Eagle and onto surface of another world. His words, “that’s one small step for man, one giant leap for mankind,” would go on to become the most famous spoken in the twentieth century, but it’s the words of another man that day that I think really drive home the magnitude of the event for me.
As Aldrin and Armstrong sat in the Eagle a world away, Walter Cronkite sat where he did every day for 19 years: the news desk at CBS. As Armstrong announced their successful landing to the world, Cronkite’s reaction was astonishing: he laughed. Not a short laugh, but a long, drawn-out one, after which he managed to get out just two words “oh, boy!” The camera showed him looking around in joyful disbelief while a co-anchor wiped tears from his eyes.
Here was a man who, as a reporter, had landed behind enemy lines during World War II. He’d consoled a nation as their president lay dying and would steer them through the resignation and humiliation of another. And, yet, here, in this moment, at this time, he simply had no words. America’s most trusted man was, like the estimated twenty percent of the world’s population watching the broadcast, just speechless.
One of the great challenges in understanding history is to see the context of an event. What was the average person fearful of? Hoping for? Busy with? Did the average citizen of Gaul care about Ceasar? Did denizens of Strasbourg wonder at Gutenberg’s printing press? We will probably never know, but, in the case of men standing on the Moon, the results seem unequivocal. When even the most experienced among us are astonished, then surely we’re glimpsing that rarest form of history: the wholly unprecedented. And, even forty-five years later, it still doesn’t fail to impress.
Thanks for listening to this episode of the Monthly News Roundup. For more astronomy news and commentary, visit http://cosmicchatter.org or follow @cosmic_chatter on Twitter. As always, you can contact us with your comments and corrections at email@example.com.
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365 Days of Astronomy
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