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broncosteven
06-07-2010, 07:59 PM
Dawn is a hot name for a spacecraft:

NASA's Dawn Spacecraft Fires Past Record for Speed Change

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-192&cid=release_2010-192

PASADENA, Calif. - Deep in the heart of the asteroid belt, on its way to the first of the belt's two most massive inhabitants, NASA's ion-propelled Dawn spacecraft has eclipsed the record for velocity change produced by a spacecraft's engines.

The previous standard-bearer for velocity change, NASA's Deep Space 1, also impelled by ion propulsion, was the first interplanetary spacecraft to use this technology. The Deep Space 1 record fell on Saturday, June 5, when the Dawn spacecraft's accumulated acceleration over the mission exceeded 4.3 kilometers per second (9,600 miles per hour).

"We are using this amazing ion-engine technology as a stepping-stone to orbit and explore two of the asteroid belt's most mysterious objects, Vesta and Ceres," said Robert Mase, Dawn project manager from NASA's Jet Propulsion Laboratory in Pasadena, Calif.

A spacecraft's change in velocity refers to its ability to change its path through space by using its own rocket engines. This measurement of change begins only after the spacecraft exits the last stage of the launch vehicle that hurled it into space.

To get to where it is in both the record books and the asteroid belt, the Dawn spacecraft had to fire its three engines - one at a time-- for a cumulative total of 620 days. In that time, it has used less than 165 kilograms (363 pounds) of xenon propellant. Over the course of its eight-plus-year mission, Dawn's three ion engines are expected to accumulate 2,000 days of operation -- 5.5 years of thrusting -- for a total change in velocity of more than 38,620 kilometers per hour (24,000 miles per hour).

"I am delighted that it will be Dawn that surpasses DS1's record," said Marc Rayman, chief engineer for the Dawn mission and a previous project manager for Deep Space 1."It is a tribute to all those involved in the design and operations of this remarkable spacecraft."

At first glance, Dawn's pedal-to-the-metal performance is a not-so-inspiring 0-to-97 kilometers per hour (0-to-60 miles per hour) in four days. But due to its incredible efficiency, it expends only 37 ounces of xenon propellant during that time. Then take into consideration that after those four days of full-throttle thrusting, it will do another four days, and then another four. By the end of 12 days, the spacecraft will have increased its velocity by more than 290 kilometers per hour (180 miles per hour), with more days and weeks and months of continuous thrusting to come. In one year's time, Dawn's ion propulsion system can increase the spacecraft's speed by 8,850 kilometers per hour (5,500 miles per hour), while consuming the equivalent of only 16 gallons of fuel.

"This is a special moment for the spacecraft team," said Dawn's principal investigator, Chris Russell of the University of California Los Angeles. "In only 407 days, our minds will be on another set of records, the data records that Dawn will transmit when we enter Vesta orbit."

Dawn's 4.8-billion-kilometer (3-billion-mile) odyssey includes exploration of asteroid Vesta in 2011 and 2012, and the dwarf planet Ceres in 2015. These two icons of the asteroid belt have been witness to much of our solar system's history. By using the same set of instruments at two separate destinations, scientists can more accurately formulate comparisons and contrasts. Dawn's science instrument suite will measure shape, surface topography and tectonic history, elemental and mineral composition, as well as seek out water-bearing minerals. In addition, the way the Dawn spacecraft orbits both Vesta and Ceres will be used to measure the celestial bodies' masses and gravity fields.

While Dawn surpassed Deep Space 1's record for velocity change, Deep Space 1 will continue to reign as holder for the longest duration of powered spaceflight for another few months. Dawn is expected to take over that record on about August 10 of this year.

The Dawn mission to Vesta and Ceres is managed by JPL, a division of the California Institute of Technology in Pasadena, for NASA's Science Mission Directorate, Washington. The University of California, Los Angeles, is responsible for overall Dawn mission science. Other scientific partners include Planetary Science Institute, Tucson, Ariz.; Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany; DLR Institute for Planetary Research, Berlin, Germany; Italian National Institute for Astrophysics, Rome; and the Italian Space Agency, Rome. Orbital Sciences Corporation of Dulles, Va., designed and built the Dawn spacecraft.

To learn more about Dawn and its mission to the asteroid belt, visit: http://www.nasa.gov/dawn

broncosteven
06-07-2010, 08:05 PM
What is Consuming Hydrogen and Acetylene on Titan?

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-190&cid=release_2010-190


PASADENA, Calif. - Two new papers based on data from NASA's Cassini spacecraft scrutinize the complex chemical activity on the surface of Saturn's moon Titan. While non-biological chemistry offers one possible explanation, some scientists believe these chemical signatures bolster the argument for a primitive, exotic form of life or precursor to life on Titan's surface. According to one theory put forth by astrobiologists, the signatures fulfill two important conditions necessary for a hypothesized "methane-based life."

One key finding comes from a paper online now in the journal Icarus that shows hydrogen molecules flowing down through Titan's atmosphere and disappearing at the surface. Another paper online now in the Journal of Geophysical Research maps hydrocarbons on the Titan surface and finds a lack of acetylene.

This lack of acetylene is important because that chemical would likely be the best energy source for a methane-based life on Titan, said Chris McKay, an astrobiologist at NASA Ames Research Center, Moffett Field, Calif., who proposed a set of conditions necessary for this kind of methane-based life on Titan in 2005. One interpretation of the acetylene data is that the hydrocarbon is being consumed as food. But McKay said the flow of hydrogen is even more critical because all of their proposed mechanisms involved the consumption of hydrogen.

"We suggested hydrogen consumption because it's the obvious gas for life to consume on Titan, similar to the way we consume oxygen on Earth," McKay said. "If these signs do turn out to be a sign of life, it would be doubly exciting because it would represent a second form of life independent from water-based life on Earth."

To date, methane-based life forms are only hypothetical. Scientists have not yet detected this form of life anywhere, though there are liquid-water-based microbes on Earth that thrive on methane or produce it as a waste product. On Titan, where temperatures are around 90 Kelvin (minus 290 degrees Fahrenheit), a methane-based organism would have to use a substance that is liquid as its medium for living processes, but not water itself. Water is frozen solid on Titan's surface and much too cold to support life as we know it.

The list of liquid candidates is very short: liquid methane and related molecules like ethane. While liquid water is widely regarded as necessary for life, there has been extensive speculation published in the scientific literature that this is not a strict requirement.

The new hydrogen findings are consistent with conditions that could produce an exotic, methane-based life form, but do not definitively prove its existence, said Darrell Strobel, a Cassini interdisciplinary scientist based at Johns Hopkins University in Baltimore, Md., who authored the paper on hydrogen.

Strobel, who studies the upper atmospheres of Saturn and Titan, analyzed data from Cassini's composite infrared spectrometer and ion and neutral mass spectrometer in his new paper. The paper describes densities of hydrogen in different parts of the atmosphere and the surface. Previous models had predicted that hydrogen molecules, a byproduct of ultraviolet sunlight breaking apart acetylene and methane molecules in the upper atmosphere, should be distributed fairly evenly throughout the atmospheric layers.

Strobel found a disparity in the hydrogen densities that lead to a flow down to the surface at a rate of about 10,000 trillion trillion hydrogen molecules per second. This is about the same rate at which the molecules escape out of the upper atmosphere.

"It's as if you have a hose and you're squirting hydrogen onto the ground, but it's disappearing," Strobel said. "I didn't expect this result, because molecular hydrogen is extremely chemically inert in the atmosphere, very light and buoyant. It should 'float' to the top of the atmosphere and escape."

Strobel said it is not likely that hydrogen is being stored in a cave or underground space on Titan. The Titan surface is also so cold that a chemical process that involved a catalyst would be needed to convert hydrogen molecules and acetylene back to methane, even though overall there would be a net release of energy. The energy barrier could be overcome if there were an unknown mineral acting as the catalyst on Titan's surface.

The hydrocarbon mapping research, led by Roger Clark, a Cassini team scientist based at the U.S. Geological Survey in Denver, examines data from Cassini's visual and infrared mapping spectrometer. Scientists had expected the sun's interactions with chemicals in the atmosphere to produce acetylene that falls down to coat the Titan surface. But Cassini detected no acetylene on the surface.

In addition Cassini's spectrometer detected an absence of water ice on the Titan surface, but loads of benzene and another material, which appears to be an organic compound that scientists have not yet been able to identify. The findings lead scientists to believe that the organic compounds are shellacking over the water ice that makes up Titan's bedrock with a film of hydrocarbons at least a few millimeters to centimeters thick, but possibly much deeper in some places. The ice remains covered up even as liquid methane and ethane flow all over Titan's surface and fill up lakes and seas much as liquid water does on Earth.

"Titan's atmospheric chemistry is cranking out organic compounds that rain down on the surface so fast that even as streams of liquid methane and ethane at the surface wash the organics off, the ice gets quickly covered again," Clark said. "All that implies Titan is a dynamic place where organic chemistry is happening now."

The absence of detectable acetylene on the Titan surface can very well have a non-biological explanation, said Mark Allen, principal investigator with the NASA Astrobiology Institute Titan team. Allen is based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. Allen said one possibility is that sunlight or cosmic rays are transforming the acetylene in icy aerosols in the atmosphere into more complex molecules that would fall to the ground with no acetylene signature.

"Scientific conservatism suggests that a biological explanation should be the last choice after all non-biological explanations are addressed," Allen said. "We have a lot of work to do to rule out possible non-biological explanations. It is more likely that a chemical process, without biology, can explain these results - for example, reactions involving mineral catalysts."

"These new results are surprising and exciting," said Linda Spilker, Cassini project scientist at JPL. "Cassini has many more flybys of Titan that might help us sort out just what is happening at the surface."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter was designed, developed and assembled at JPL.

For more information about the Cassini-Huygens mission visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov.

Brewer
06-07-2010, 08:43 PM
I know several life forms here on Earth that produce methane as a waste product... :welcome: Otherwise, that's some pretty cool stuff. I dig the ion propulsion system's efficiency.

Dr. Broncenstein
06-07-2010, 08:44 PM
"Continually thrusting for days and weeks."

OBF1
06-07-2010, 09:13 PM
Great articles, make the brain work overtime..... which is a good thing.

Tombstone RJ
06-07-2010, 09:22 PM
Pretty strange what is happening on Titan. Definitely need more research done there...

watermock
06-07-2010, 09:36 PM
X-51 just another record. (scram jet).

Like mach 7 or something.

I bounces off the atmospere...how it re-enters dunno.

randomtask
06-07-2010, 09:37 PM
The idea of Methane-based life is an incredibly cool idea, and if we found such life, would definitely be one of the most important discoveries of the new century.

I'll definitely keep an eye on how the Cassini-Huygens mission progresses. Hopefully this program they stick with, unlike the moon base program.:notthissh

On the ion propulsion part, do you know what type it is (Electrostatic, electromagnetic, something else)? What did NASA do to improve over the Deep space 1's engine design?

colonelbeef
06-08-2010, 11:13 AM
"Dawn is a pretty hot name for a spacecraft"

hah, agree

bfoflcommish
06-08-2010, 11:42 AM
X-51 just another record. (scram jet).

Like mach 7 or something.

I bounces off the atmospere...how it re-enters dunno.



yeah we know you are out there alright

Rock Chalk
06-08-2010, 12:25 PM
The idea of Methane-based life is an incredibly cool idea, and if we found such life, would definitely be one of the most important discoveries of the new century.

I'll definitely keep an eye on how the Cassini-Huygens mission progresses. Hopefully this program they stick with, unlike the moon base program.:notthissh

On the ion propulsion part, do you know what type it is (Electrostatic, electromagnetic, something else)? What did NASA do to improve over the Deep space 1's engine design?

If they find out there is methane based life then you can rest assured nearly every solar system in the universe will have life.

If Life could evolve, on two separate planets, in two separate systems (water and methane), in one solar system then life effectively will be everywhere. There are probably many many thousands of times more planets like Titan than there are like Earth and methane based life would likely be the most common system for life. IF they can prove it.

Kaylore
06-08-2010, 01:03 PM
We should double the engines and make TIE fighters.

http://img.photobucket.com/albums/v139/SithJada/Star%20Wars%20pics/Transports/TieFighter.jpg

snowspot66
06-08-2010, 02:15 PM
If they find out there is methane based life then you can rest assured nearly every solar system in the universe will have life.

If Life could evolve, on two separate planets, in two separate systems (water and methane), in one solar system then life effectively will be everywhere. There are probably many many thousands of times more planets like Titan than there are like Earth and methane based life would likely be the most common system for life. IF they can prove it.

That would make us the lottery winners. Not life itself. That would be a mind bender.

Que
06-08-2010, 02:23 PM
"Continually thrusting for days and weeks."

Like a lumberjack baby!

Rohirrim
06-08-2010, 02:29 PM
My wife considers me a methane based life form.

Houshyamama
06-08-2010, 03:16 PM
X-51 just another record. (scram jet).

Like mach 7 or something.

I bounces off the atmospere...how it re-enters dunno.

yeah dude, I'm pumped for this technology... been following it for a long time.

broncosteven
06-08-2010, 04:16 PM
X-51 just another record. (scram jet).

Like mach 7 or something.

I bounces off the atmospere...how it re-enters dunno.

It set it for time at speed (mach6) not actual speed if I remember right.

It is only built for Hypersonic testing, it does not leave the atmosphere. They do not even retrieve it. It just drops into the ocean.

broncosteven
06-23-2010, 08:19 PM
http://sn121w.snt121.mail.live.com/default.aspx?rru=getmsg?msg=DCE90C59-7F11-11DF-97E6-002264C17D5E

Earth-like Planets May Be Ready for Their Close-Up

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2010-207&cid=release_2010-207

Many scientists speculate that our galaxy could be full of places like Pandora from the movie "Avatar" -- Earth-like worlds in solar systems besides our own.

That doesn't mean such worlds have been easy to find, however. Of the 400-plus planets so far discovered, none could support life as we know it on Earth.

"The problem with finding Earth-like planets," said Stefan Martin, an engineer at NASA's Jet Propulsion Laboratory, Pasadena, Calif., "is that their host stars can emit 10 million times more infrared light than the planet itself. And because planets like ours are small and orbit very close to their respective stars, it makes Earths almost impossible to see."

Together with A.J. Booth (formerly at JPL and now at Sigma Space Corp., Lanham, Md.), Martin may have developed a way to make this almost impossible feat a reality.

Their instrument design, called a "nulling interferometer," observes planets in infrared light, where they are easier to detect. It is designed to combine starlight captured by four different telescopes, arranging the light waves from the star in such a way that they cancel each other out. "We're able to make the star look dimmer -- basically turning it off," Martin said.

Nulling interferometry is not a new idea, but what sets the results from Martin and Booth apart is how effective it turned out to be. "Our null depth is 10 to 100 times better than previously achieved by other systems," Martin said. "This is the first time someone has cross-combined four telescopes, set up in pairs, and achieved such deep nulls. It's extreme starlight suppression."

That suppression could allow scientists to get a better look at exoplanets than ever before. "We're able to make the planet flash on and off so that we can detect it," Martin said. "And because this system makes the light from the star appear 100 million times fainter, we would be able to see the planet we're looking for quite clearly."

More at the link above