Mi lista de blogs

jueves, 28 de agosto de 2014

NASA : Testing Composite Cryotank Technology For Future Deep Space Missions


Testing Composite Cryotank Technology For Future Deep Space Missions
NASA has completed a complex series of tests on one of the largest composite cryogenic fuel tanks ever manufactured, bringing the aerospace industry much closer to designing, building, and flying lightweight, composite tanks on rockets. At NASA's Marshall Space Flight Center in Huntsville, Alabama, the tank was lowered into a structural test stand where it was tested with cryogenic hydrogen and structural loads to simulate stresses the tank would experience during launch. The project is part of NASA's Space Technology Mission Directorate, which is innovating, developing, testing and flying hardware for use in NASA's future missions.
Cryogenic propellants are gasses chilled to subfreezing temperatures and condensed to form highly combustible liquids, providing high-energy propulsion solutions critical to future, long-term human exploration missions beyond low-Earth orbit. In the past, propellant tanks have been fabricated out of metals. Switching from metallic to composite construction holds the potential to dramatically increase the performance capabilities of future space systems through a dramatic reduction in weight.
Image Credit: NASA/David Olive
 
 
NASA Completes Successful Battery of Tests on Composite Cryotank
Youtube Override: 
 
NASA has completed a complex series of tests on one of the largest composite cryogenic fuel tanks ever manufactured, bringing the aerospace industry much closer to designing, building, and flying lightweight, composite tanks on rockets.

“This is one of NASA’s major technology accomplishments for 2014,” said Michael Gazarik, NASA’s associate administrator for Space Technology. “This is the type of technology that can improve competitiveness for the entire U.S. launch industry, not to mention other industries that want to replace heavy metal components with lightweight composites. These tests, and others we have conducted this year on landing technologies for Mars vehicles, show how technology development is the key to driving exploration.” 
Cryotank testing at Marshall Space Flight Center
One of the largest composite cryotanks ever built recently completed a battery of tests at NASA's Marshall Space Flight Center in Huntsville, Alabama. The tank was lowered into a structural test stand where it was tested with cryogenic hydrogen and structural loads were applied to simulate stresses the tank would experience during launch.
Image Credit: 
NASA/David Olive
 
The demanding series of tests on the 18-foot (5.5-meter) diameter tank were conducted inside a test stand at NASA’s Marshall Space Flight Center in Huntsville, Alabama. Engineers added structural loads to the tank to replicate the physical stresses launch vehicles experience during flight.
In other tests, the tank successfully maintained fuels at extremely low temperatures and operated at various pressures.  Engineers filled the tank with almost 30,000 gallons of liquid hydrogen chilled to -423 degrees Fahrenheit, and repeatedly cycled the pressure between 20 to 53 pounds per square inch -- the pressure limit set for the tests.
“This is the culmination of a three-year effort to design and build a large high-performance tank with new materials and new processes and to test it under extreme conditions,” said John Vickers, the project manager for the Composite Cryogenic Technology Demonstration Project, which is one of the key technologies funded by NASA’s Game Changing Development Program. “We are a step closer to demonstrating in flight a technology that could reduce the weight of rocket tanks by 30 percent and cut costs by at least 25 percent.”
The composite rocket fuel tank, which arrived at Marshall on March 26 aboard NASA's Super Guppy airplane, was built by the Boeing Company near Seattle.
“Never before has a tank of this size been proven to sustain the thermal environment of liquid hydrogen at these pressures,” said Dan Rivera, Boeing program manager for the cryotank project. “Our design is also more structurally efficient then predecessors. This is a significant technology achievement for NASA, Boeing and industry. “We are looking at composite fuel tanks for many aerospace applications.”
The project is part of NASA's Space Technology Mission Directorate, which is innovating, developing, testing and flying hardware for use in NASA's future missions. Over the next year, the directorate will make significant new investments to address several high-priority challenges in achieving safe and affordable deep space exploration. Next-generation technologies including composite systems have the potential to make rockets, including NASA’s Space Launch System -- a deep space rocket being developed at Marshall -- more capable and affordable. 
B-roll video of the cryotank is available at:
For more information about NASA's investment in space technology, visit:
 
NASA
Guillermo Gonzalo Sánchez Achutegui
Inscríbete en el Foro del blog y participa : A Vuelo De Un Quinde - El Foro!

martes, 26 de agosto de 2014

NASA : Solar Dynamics Observatory Captures Images of a Late Summer Flare


 
Solar Dynamics Observatory Captures Images of a Late Summer Flare
On Aug. 24, 2014, the sun emitted a mid-level solar flare, peaking at 8:16 a.m. EDT. NASA's Solar Dynamics Observatory captured images of the flare, which erupted on the left side of the sun. Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however -- when intense enough -- they can disturb the atmosphere in the layer where GPS and communications signals travel. This flare is classified as an M5 flare. M-class flares are ten times less powerful than the most intense flares, called X-class flares.
Image Credit: NASA/SDO
NASA
Guillermo Gonzalo Sánchez Achutegui
ayabaca@gmail.com
ayabaca@hotmail.com
ayabaca@yahoo.com
Inscríbete en el Foro del blog y participa : A Vuelo De Un Quinde - El Foro!

NASA : Eta Carinae: Our Neighboring Superstars


 
Eta Carinae: Our Neighboring Superstars
The Eta Carinae star system does not lack for superlatives. Not only does it contain one of the biggest and brightest stars in our galaxy, weighing at least 90 times the mass of the sun, it is also extremely volatile and is expected to have at least one supernova explosion in the future.

As one of the first objects observed by NASA’s Chandra X-ray Observatory after its launch some 15 years ago, this double star system continues to reveal new clues about its nature through the X-rays it generates.

Astronomers reported extremely volatile behavior from Eta Carinae in the 19th century, when it became very bright for two decades, outshining nearly every star in the entire sky. This event became known as the “Great Eruption.” Data from modern telescopes reveal that Eta Carinae threw off about ten times the sun’s mass during that time. Surprisingly, the star survived this tumultuous expulsion of material, adding “extremely hardy” to its list of attributes.

Today, astronomers are trying to learn more about the two stars in the Eta Carinae system and how they interact with each other. The heavier of the two stars is quickly losing mass through  wind streaming away from its surface at over a million miles per hour. While not the giant purge of the Great Eruption, this star is still losing mass at a very high rate that will add up to the sun’s mass in about a millennium.

Though smaller than its partner, the companion star in Eta Carinae is also massive, weighing in at about 30 times the mass of the sun. It is losing matter at a rate that is about a hundred times lower than its partner, but still a prodigious weight loss compared to most other stars. The companion star beats the bigger star in wind speed, with its wind clocking in almost ten times faster.

When these two speedy and powerful winds collide, they form a bow shock – similar to the sonic boom from a supersonic airplane – that then heats the gas between the stars. The temperature of the gas reaches about ten million degrees, producing X-rays that Chandra detects.

The Chandra image of Eta Carinae shows low energy X-rays in red, medium energy X-rays in green, and high energy X-rays in blue. Most of the emission comes from low and high energy X-rays. The blue point source is generated by the colliding winds, and the diffuse blue emission is produced when the material that was purged during the Great Eruption reflects these X-rays. The low energy X-rays further out show where the winds from the two stars, or perhaps material from the Great Eruption, are striking surrounding material. This surrounding material might consist of gas that was ejected before the Great Eruption.  

An interesting feature of the Eta Carinae system is that the two stars travel around each other along highly elliptical paths during their five-and-a-half-year long orbit. Depending on where each star is on its oval-shaped trajectory, the distance between the two stars changes by a factor of twenty. These oval-shaped trajectories give astronomers a chance to study what happens to the winds from these stars when they collide at different distances from one another.

Throughout most of the system's orbit, the X-rays are stronger at the apex, the region where the winds collide head-on. However, when the two stars are at their closest during their orbit (a point that astronomers call “periastron”), the X-ray emission dips unexpectedly.

To understand the cause of this dip, astronomers observed Eta Carinae with Chandra at periastron in early 2009. The results provided the first detailed picture of X-ray emission from the colliding winds in Eta Carinae. The study suggests that part of the reason for the dip at periastron is that X-rays from the apex are blocked by the dense wind from the more massive star in Eta Carinae, or perhaps by the surface of the star itself.

Another factor responsible for the X-ray dip is that the shock wave appears to be disrupted near periastron, possibly because of faster cooling of the gas due to increased density, and/or a decrease in the strength of the companion star’s wind because of extra ultraviolet radiation from the massive star reaching it. Researchers are hoping that Chandra observations of the latest periastron in August 2014 will help them determine the true explanation.

These results were published in the April 1, 2014 issue of The Astrophysical Journal and are available online. The first author of the paper is Kenji Hamaguchi of Goddard Space Flight Center in Greenbelt, MD, and his co-authors are Michael Corcoran of Goddard Space Flight Center (GSFC); Christopher Russell of University of Delaware in Newark, DE; A. Pollock from the European Space Agency in Madrid, Spain; Theodore Gull, Mairan Teodoro, and Thomas I. Madura from GSFC; Augusto Damineli from Universidade de Sao Paulo in Sao Paulo, Brazil and Julian Pittard from the University of Leeds in the UK.

NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington, DC. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.
Image credit: NASA/CXC/GSFC/K.Hamaguchi, et al.
NASA
Guillermo Gonzalo Sánchez Achutegui
ayabaca@gmail.com
ayabaca@hotmail.com
ayabaca@yahoo.com
Inscríbete en el Foro del blog y participa : A Vuelo De Un Quinde - El Foro!