Happy Friday everyone. You will be in good hands with Stacey Nakamura while I am in Peru. Have a safe weekend. Go Texans.
| | JSC TODAY CATEGORIES - Headlines
- The 'George Award' is Back - Organizations/Social
- Lead Like a Rock Star
- Space Serenity Al-Anon Meeting Sept. 9
- POSTPONED: AFGE Lunch and Learn - Jobs and Training
- Human Systems Academy Lecture - Community
- International Observe the Moon Night at LPI |  |
| Headlines - The 'George Award' is Back
The George Award is JSC's answer to the Oscar for safety/health event participation. The good thing is … it doesn't go to the swiftest in the race. Instead, this special award, named in honor of former JSC Director George W.S. Abbey, will be given to the directorate that has the highest percentage participation for the Oct. 9 Safety and Health Day space race activities. The George Award, a handsome space-motif trophy, will be yours to display for the year as a reminder to your employees and visitors alike that taking part in a health event, as a team, is important to you and something you worked harder to accomplish than anyone else at JSC in the year 2014. Winning the George Award could be a very proud day for your directorate. Stay tuned to JSC Today for more information on how your organization can earn this prestigious trophy. Organizations/Social - Lead Like a Rock Star
Please join us for an enlightening September JSC National Management Association chapter luncheon presentation with Dayna Steele, author and speaker, for her talk "Lead like a Rock Star." When: Thursday, Sept. 25 Time: 11:30 a.m. to 1 p.m. Location: Gilruth Alamo Ballroom Cost for members: FREE Cost for non-members: $20 There are three great menu options to choose from: - Mustard pork loin medallions with apple chutney, dijon-roasted potatoes and roasted asparagus
- Blackened chicken with red bell peppers and parmesan cream, angel hair pasta and roasted asparagus
- Vegetarian dish: pasta primavera with whole wheat rotini
Desserts: Pineapple/coconut sorbet Event Date: Thursday, September 25, 2014 Event Start Time:11:30 AM Event End Time:1:00 PM
Event Location: Gilruth - Alamo Ballroom
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Leslie N. Smith x46752
[top] - Space Serenity Al-Anon Meeting Sept. 9
"THINK!" reminds Al-Anon members that just as kids go back to school, we school our thoughts to calmly process events and inputs. Our 12-step meeting is for co-workers, families and friends of those who work or live with the family disease of alcoholism. We will meet Tuesday, Sept. 9, in Building 32, Room 146, from 12 noon to 12:45 p.m. Visitors are welcome. - POSTPONED: AFGE Lunch and Learn
Due to unforeseen circumstances, this event has been postponed: The American Federation of Government Employees (AFGE) Union Lunch and Learn scheduled for Monday, Sept. 8, and Wednesday, Sept. 10. Open to all non-supervisory JSC civil servants. Come and hear what AFGE officials have to talk about: - Know your rights
- Union benefits
- Union representation
Stop by on your lunch break on Sept. 8 between the hours of 11 a.m. and 2 p.m. in Building 45, Room 251, or on Sept. 10 between the hours of 11 a.m. and 2 p.m. in Building 1, Room 376G. Jobs and Training - Human Systems Academy Lecture
Join the Human Systems Academy lecture on "Visual Impairment Intracranial Pressure." This lecture will provide insight into documented changes in visual acuity and eye anatomy that have been experienced by some astronauts after long-duration missions. Specifically, the lecture answers: What is the relation to intracranial pressure, and how does this translate into a human long-duration spaceflight risk? Community - International Observe the Moon Night at LPI
Tomorrow, Sept. 6, the whole world will collectively admire and celebrate our moon during International Observe the Moon Night (InOMN). Join the Lunar and Planetary Institute (LPI) and the JSC Astronomy Society (JSCAS) as we celebrate the fifth anniversary of this worldwide event. During the LPI event, you can: - Learn about the moon through hands-on activities
- Observe the moon through telescopes provided by the JSCAS (weather permitting)
- View lunar samples returned by Apollo astronauts
- Speak with lunar scientists
- Hear lunar science and exploration presentations from LPI scientists Dr. Georgiana Kramer and Dr. Walter Kiefer
This free event at LPI begins at 8 p.m. and ends at 10 p.m. LPI is located in the USRA building at 3600 Bay Area Blvd. in Clear Lake; the entrance is located on Middlebrook Drive. For more information about InOMN, please click here. Event Date: Saturday, September 6, 2014 Event Start Time:8:00 PM Event End Time:10:00 PM
Event Location: LPI, 3600 Bay Area Blvd.
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Andrew Shaner
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| JSC Today is compiled periodically as a service to JSC employees on an as-submitted basis. Any JSC organization or employee may submit articles. Disclaimer: Accuracy and content of these notes are the responsibility of the submitters. |
NASA and Human Spaceflight News
Friday – September 5, 2014
HEADLINES AND LEADS
WIA Honors Carolyn Huntoon, Five Other "Exceptional Women"
Women in Aerospace (WIA) announced the winners of its six annual awards that honor achievements by women in the aerospace field today (September 4). Among the winners is Carolyn Huntoon, a trailblazer for women at NASA and the first woman to serve as Director of the Johnson Space Center (1994-1996).
Falling on the Moon: How Much Gravity Do Astronauts Really Need?
For all the heroics of space travel, life as an astronaut comes with an array of indignities. Adult diapers. Pee funnels. And then there are the awkward tumbles on the moon for all the world to see.
Engineers Conduct Low Light Test on New Technology for James Webb Space Telescope
NASA engineers have recently inspected a new piece of technology developed for the James Webb Space Telescope (JWST), the Micro-Shutter Array (MSA), with a low light test at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Developed at Goddard to allow Webb's Near Infrared Spectrograph (NIRSpec) to obtain spectra of more than 100 objects in the universe simultaneously, MSA uses thousands of tiny shutters to capture spectra from selected objects of interest in space and block out light from all other sources. The array is composed of four independent quadrants, each one housing a Micro Electro-Mechanical Systems (MEMS) array, made up of 365 x 171 shutters, whose dimensions are only 80 µm x 180 µm. There are more than 1000 electrical connections obtained with bump bonding and hair-thin wire bonding techniques between each array and its quadrant. Each quadrant also houses four electronic chip controls and monitors the functionality of the shutters.
Two Orbiters, One Comet Arriving At Mars Soon
Frank Morring, Jr., Jay Menon - Aviation Week & Space Technology
Scientists and spacecraft controllers in Denver, Bangalore and many points in between are preparing for a rush of activity at the planet Mars, where two new spacecraft designed to study its atmosphere will arrive later this month, followed shortly thereafter by a rare Oort Cloud comet.
Whoops! So-Called 'Asteroid' Is Actually a Comet
A previously unknown "asteroid" spotted by a NASA telescope is actually a comet, according to recent observations.
Rainfall on Titan May Create Propane Aquifers, Study Suggests
Paul Scott Anderson - America Space
Saturn's largest moon Titan is a very alien yet eerily Earth-like world, with rain, rivers, lakes and seas; seen from above, the landscape has a familiar look to it. But those lakes, seas and rivers are fed by a different kind of rainfall – liquid methane/ethane. It is far too cold on the surface for liquid water, but the liquid hydrocarbons nicely fill in for H20 in Titan's "water cycle." Now, a new study shows how this rainfall interacts with and changes underground aquifers. COMPLETE STORIES
WIA Honors Carolyn Huntoon, Five Other "Exceptional Women"
Women in Aerospace (WIA) announced the winners of its six annual awards that honor achievements by women in the aerospace field today (September 4). Among the winners is Carolyn Huntoon, a trailblazer for women at NASA and the first woman to serve as Director of the Johnson Space Center (1994-1996).
Huntoon is being awarded WIA's Lifetime Achievement Award for her "sustained and exemplary leadership at NASA, the Office of Science and Technology Policy and the Department of Energy, her exceptional scientific contributions towards understanding the effects of spaceflight on the human body, and her dedication and mentorship of astronauts and aerospace professionals." Huntoon has a Ph.D. in physiology from Baylor College of Medicine and was deeply involved in studying how humans react to weightlessness from the earliest days of human spaceflight, including cooperation with her Soviet space medicine counterparts beginning in the early 1970s. She is quoted frequently in Lynn Sherr's biography of Sally Ride as an influential voice in the selection of the first group of astronauts that included women (Ride and five others) and mentor to them afterwards.
The other five WIA award winners are:
- Lynn Cominsky, Sonoma St. University, Rohnert Park, CA: Aerospace Awareness Award
- Allison Barto, Ball Aerospace & Technologies Corp,. Boulder, CO: Outstanding Achievement Award
- Alexandra Kindrat, Lester B. Pearson School Board, St. Thomas High School, Montreal, Canada: Aerospace Educator Award
- Samantha Pappas, Naval Air Systems Command 5.1, Patuxent River, MD: Initiative, Inspiration, Impact Award
- Leanne Caret, Boeing Defense, Space and Security, St. Louis, MO: Leadership Award
Also, the WIA Foundation awarded three scholarships to --
- Emily Zimovan, a junior in aeronautical and astronautical engineering at Purdue University
- Jessica Felde, a junior in aerospace and mechanical engineering at West Virginia University, and
- Lauren Trollinger, a junior in aerospace engineering at the University of Maryland
WIA's annual awards dinner is on October 29, 2014 at the Ritz Carlton Hotel in Arlington, VA. Contact WIA for more information. Falling on the Moon: How Much Gravity Do Astronauts Really Need?
For all the heroics of space travel, life as an astronaut comes with an array of indignities. Adult diapers. Pee funnels. And then there are the awkward tumbles on the moon for all the world to see.
In one famous episode from NASA's Apollo 17 mission in 1972, moonwalker Jack Schmitt topples over — seemingly in slow motion — as he fumbles a sample collection bag while bounding across the lunar surface. Back at Mission Control in Houston, Capcom Bob Parker calls out to Schmitt's fellow moonwalker, Gene Cernan, "Hey, Gene, would you go over and help Twinkletoes, please?"
NASA's records from the Apollo era contain pages and pages of such deadpan accounts of lunar spills. Mission controllers spent hours analyzing video footage to try to figure out why the astronauts lost balance and what techniques they used to get back up. Forty years later, new experiments might help explain why the Apollo astronauts occasionally struggled to stay upright. [The Human Body in Space: 6 Weird Facts] Humans need at least 15 percent of the level of gravity found on Earth to orient themselves, according to findings published yesterday (Sept. 3) in the journal PLOS ONE. That means the level of gravity on the moon — about 17 percent of Earth's gravity — is just barely strong enough to provide adequate cues for astronauts to know which way is up. No one has been back to the moon since Cernan and Schmitt blasted off the lunar surface in December 1972. But scientists have ways to simulate the low-gravity environment of the moon without leaving Earth.
Five men and five women participated in the experiment at the European Space Agency's Short Arm Centrifuge Facility (SAHC) in Cologne, Germany. The participants lied down on a platform in the human centrifuge with their feet facing away from the center. Depending on how fast the machine spun, the recruits experienced different levels of gravity, from 0g, close to the weightless environment in orbit, to 1g, the force humans feel while standing on Earth, explained study leader Laurence Harris of York University in Canada.
While whirling around in the centrifuge, the participants took a perceptual test, in which they had to choose whether the tilted letter they were looking at on a circular computer screen was a "p" or "d." In a near-zero-gravity environment, such as the International Space Station, astronauts need to rely on visual cues alone to orient themselves, Harris said. The results of the experiment found that gravity only starts influencing a person's sense of up and down once it hits about 0.15g.
"In a low gravitational field, such as on the moon, you'll have an unreliable estimate for what gravity's telling you is up," Harris told Space.com. In retrospect, he said, it's not surprising that a YouTube search for "astronauts falling over" yields so many results. Disoriented astronauts don't just risk tipping over. They might flip a switch the wrong way in an emergency, or misjudge how an object is going to behave when it's dropped or thrown. Apollo astronauts at the wheel of NASA's moon rovers reported that they had a hard time estimating the incline of the lunar terrain while driving. The findings suggest engineers building extraterrestrial cars probably will need to make sure they include an instrument in the dashboard that tells the pitch of the vehicle for astronaut drivers who are unable to rely on their own senses, Harris said.
"It's just really important that we understand our sensory systems before we go into extreme environments," Harris said.
There is good news for space program managers with their sights set on Mars: With 38 percent of Earth's gravity, the Red Planet's gravity should be sufficient for astronauts to easily orient themselves and maintain balance, the researchers said.
Engineers Conduct Low Light Test on New Technology for James Webb Space Telescope
NASA engineers have recently inspected a new piece of technology developed for the James Webb Space Telescope (JWST), the Micro-Shutter Array (MSA), with a low light test at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Developed at Goddard to allow Webb's Near Infrared Spectrograph (NIRSpec) to obtain spectra of more than 100 objects in the universe simultaneously, MSA uses thousands of tiny shutters to capture spectra from selected objects of interest in space and block out light from all other sources. The array is composed of four independent quadrants, each one housing a Micro Electro-Mechanical Systems (MEMS) array, made up of 365 x 171 shutters, whose dimensions are only 80 µm x 180 µm. There are more than 1000 electrical connections obtained with bump bonding and hair-thin wire bonding techniques between each array and its quadrant. Each quadrant also houses four electronic chip controls and monitors the functionality of the shutters.
Each of the quarter of a million shutters can be addressed independently to obtain any pattern of opened/closed 'slits'. A narrow, strong quadrupole magnet, mounted on a linear moving arm, sweeps up/down across the magnetically sensitive shutters pushing them open. Electrical signals, synchronised with the sweep, are applied to the shutters and to their side walls causing them to electrostatically latch open against the walls. On the return sweep of the magnet, the desired pattern of open shutters is achieved by allowing walls that are not required for the slit pattern to discharge and to gently close the shutters by the dampening magnetic force.
"To build a telescope that can peer farther than Hubble can, we needed brand new technology," said Murzy Jhabvala, chief engineer of Goddard's Instrument Technology and Systems Division. "We've worked on this design for over six years, opening and closing the tiny shutters tens of thousands of times in order to perfect the technology."
Harvey Moseley, the Microshutter Principal Investigator, adds, "The microshutters are a remarkable engineering feat that will have applications both in space and on the ground, even outside of astronomy in biotechnology, medicine and communications."
JWST will be a large infrared telescope with a 6.5-meter primary mirror. The project is working to a 2018 launch date.
Webb is an international collaboration between NASA, the European Space Agency (ESA ), and the Canadian Space Agency (CSA ). The NASA Goddard Space Flight Center is managing the development effort. The main industrial partner is Northrop Grumman; the Space Telescope Science Institute will operate Webb after launch.
Two Orbiters, One Comet Arriving At Mars Soon
Frank Morring, Jr., Jay Menon - Aviation Week & Space Technology
Scientists and spacecraft controllers in Denver, Bangalore and many points in between are preparing for a rush of activity at the planet Mars, where two new spacecraft designed to study its atmosphere will arrive later this month, followed shortly thereafter by a rare Oort Cloud comet.
If all goes as planned, the two orbiters and the comet Siding Spring should add volumes to human knowledge about where most of the red planet's water went, and perhaps about how it got there in the beginning.
NASA's only Mars mission in the current launch window—the $671 million Mars Atmosphere and Volatile Evolution (Maven)—is expressly designed to investigate whether the water that once ran on the surface escaped into space. India's Mangalyaan Mars Orbiter Mission (MOM)—its first flight to the red planet—can address some of the same questions.
And Siding Spring's flyby of Mars will be the equivalent of a free trip to the Oort Cloud, the mysterious realm of icy planetesimals 5 trillion miles from the Sun, which might have showered the inner Solar System with primordial water and perhaps even the building blocks of life.
Mars being Mars, there is also a risk of spacecraft failure, compounded by the danger posed by high-speed comet debris. At 34 mi./sec.—the closing speed as Siding Spring crosses the orbit of Mars—even a dust mote could damage or destroy a delicate instrument or critical piece of spacecraft hardware. So Maven and MOM will interrupt their planned checkout periods to hunker down as the comet passes only 80,000 mi. from the planet they, hopefully, will be orbiting.
Recent ground observations of Siding Spring's path and coma suggest the comet will not pose as big a threat as originally feared, and mission scientists on all of the spacecraft at Mars are planning to take maximum advantage of the opportunity for observation that it represents (see page 42). But the guiding principle of spacecraft operation remains "safety first," particularly after the programs have spent 10 months and plenty of money getting to their objective.
"Safety and health of the spacecraft and instruments absolutely come first," says Bruce Jakosky, a planetary scientist at the University of Colorado's Laboratory for Atmospheric and Space Physics (LASP) who is the Maven principal investigator. "There is no question about that. So if there is something that happens in the run-up to the comet, we're going to make sure we're safe. We want to survive and do our mission."
Siding Spring will pass closest to Mars on Oct. 19. Maven will arrive there on Sept. 21, followed by MOM on Sept. 24. For Jakosky, who has managed the Scout-class mission from the beginning, the first order of business will be ensuring his spacecraft gets safely into orbit. Maven controllers have been in a 60-day "command moratorium" since the end of July that was designed into the Mars orbit-insertion (MOI) sequence to circumvent any action that might go wrong and cause problems.
"We just finished our last operational readiness test for orbit insertion," he said Aug. 11. "It's basically a rehearsal, and the team went through everything we're going to be doing on MOI day to make sure we knew the procedures, knew what we had to do and were prepared. So we're doing everything we can to be ready to ensure a success."
With a 12.5-min. one-way speed-of-light delay in radio signals between the Maven spacecraft and its controllers at the Lockheed Martin facility near Denver, where it was built, the actual MOI will be completely autonomous.
Nominally, the MOI is a three-day sequence leading up to a 34-min. burn beginning a little before 10 p.m. EDT on the 21st—a Sunday—that will slow the spacecraft enough to enter orbit. But there is plenty of redundancy built into the flight-computer programming in case something goes wrong.
"If it goes correctly we go into orbit; if it doesn't, we don't," says Jakosky. "In order to ensure it goes correctly, we have engine-out capability, so that if we lose one of the six thrusters we're using, we can still get into orbit on five of them. We also have a computer-reboot capability, so if something happens during the burn, we designed it so that we could have a 13.5-min. outage, and that's enough time for the computer to reboot, decide it still has a problem, swap sides, realize it's supposed to be in the middle of its burn, reacquire attitude, resume the burn and get into orbit."
Maven navigators are working with NASA's Deep Space Network to track the spacecraft very precisely, and may decide to conduct one more trajectory correction maneuver (TCM) nine days before MOI. Jakosky says a course-correction burn planned for the end of July was canceled because it was not needed. The aim-point is a 100-by-200-km box in the sky, and so far Maven is inside the box if not headed straight for the bull's-eye.
"Whether we do [the final TCM] will depend on what the tracking shows our trajectory to be, relative to our target point," he says.
Mindful of the September 1999 loss of the Mars Climate Orbiter, the Maven MOI sequence also has provisions for an emergency orbit-raising maneuver at 24 hr. and then again at 6 hr. before insertion. The earlier spacecraft plunged too deeply into the atmosphere on arrival at the planet and disintegrated because of a mix-up between English and metric units of measurement.
"The hooks are in there so we can do it if we need it," Jakosky says. "We don't expect to need it."
Five orbital-adjustment maneuvers are planned to put Maven into its 6,200 X 150-km (3,850 X 93-mi.) science orbit. Instrument checkout will run until the end of October, when the spacecraft is scheduled to begin a year-long data-collection session designed to help scientists understand the interactions between the upper Martian atmosphere, the solar wind and other elements of the space environment.
A primary objective is to test the theory that the liquid water that once flowed on the planet's surface was lost when the solar wind and ultraviolet radiation in sunlight stripped away the heavy, wet primordial atmosphere (AW&ST Aug. 26, 2013, p. 40).
The instrument suite designed for the job consists of the Solar Wind Electron Analyzer (SWEA) to measure solar winds and electrons in the Martian ionosphere; the Solar Wind Ion Analyzer (SWIA), to measure solar wind and ion density and velocity in the planet's magnetosheath; the Suprathermal and Thermal Ion Composition (Static) instrument, which will measure ions in the atmosphere of Mars, including moderate energy escaping ions; and the Solar Energetic Particle (SEP) instrument to measure the impact of the solar wind on the planet's upper atmosphere.
Also on board are the Langmuir Probe and Waves (LPW) instrument, which includes an extreme ultraviolet sensor, to measure properties of the ionosphere, wave-heating in the upper atmosphere and extreme ultraviolet inputs into the atmosphere from the Sun. Rounding out the package is a magnetometer, which will measure interplanetary solar wind and magnetic fields in the ionosphere; a Neutral Gas and Ion Mass Spectrometer to measure the composition and isotopes of ions and thermal neutrals in the atmosphere; and an Imaging Ultraviolet Spectrograph for global remote sensing of the upper atmosphere and ionosphere at Mars.
Maven scientists designed the instruments to work across the entire range of the spacecraft's elliptical orbit, making in-situ measurements of the upper atmosphere at the lowest altitudes and then backing off for remote-sensing measurements that will allow researchers to extrapolate the low-altitude data out to global processes.
The arrival of a comet from the distant Oort Cloud, on a multimillion-year orbit that will reach its closest approach to the Sun five days after it passes Mars, is pure serendipity for comet experts. While the Maven team plans to switch off instruments that could be damaged if they are hit with debris while they are active, and to turn the spacecraft into the orientation that affords the greatest protection from any oncoming dust from Siding Spring, controllers also will interrupt instrument checkout and calibration to make observations of the event.
Still, safety comes first so at the point of greatest danger from the comet, plans call for Maven—and the other orbiters circling Mars that day—to be on the other side of the planet. Once its early orbital parameters are established, Jakosky says, controllers will adjust the orbit to minimize the danger by using Mars as a shield.
"We can get about 20 min. of hiding behind the planet, and the time of peak risk of the dust is thought to be between 30 and 60 min., so that is a significant risk reduction right there," he says.
Jakosky's counterparts at the Indian Space Research Organization are facing the same problems, and are considering the steps they can take to prepare the MOM spacecraft for the encounter. They are also working with Jakosky and his colleagues on possibly coordinating some scientific observations while the two orbiters are measuring the upper atmosphere.
"We're going to meet with some of the Indian investigators before our science mission starts to talk about what's possible," Jakosky says. "There is a strong desire to collaborate, and I don't know where it's going to head."
Of particular interest to the Maven scientists are the Lyman-alpha photometer and mass spectrometer on MOM. Maven, too, carries a mass spectrometer to measure chemical composition and coordinated observations at the same time from different locations which "allow you to separate out temporal and spatial variability," Jakosky says.
However, because the Maven and MOM teams are just beginning detailed discussions, the most likely outcome will be joint data analysis at the end of the science missions, he says. Maven scientists have also been working with scientists on the European Space Agency's Mars Express mission, which carries several instruments that can complement the Maven suite, so coordinated observations with that team are more likely. Joint data analysis with the Europeans is also in the cards, Jakosky says.
With the five-day delay in commissioning caused by the comet encounter, Maven probably will not be able to start its science mission until the second week in November. Jakosky says the annual American Geophysical Union meeting Dec. 15-19 in San Francisco is well timed for release of data on the comet encounter two months earlier.
"We think it is going to take about three months for us to come out with real, preliminary results about what Maven is telling us about Mars," Jakosky says of the primary mission objectives. "Before that, we're going to do everything we can to get data out and show people the types of things we're measuring; but in terms of grand pronouncements of what it all means, at least [for the] preliminary pronouncements, we're thinking about mid-to-late winter."
Whoops! So-Called 'Asteroid' Is Actually a Comet
A previously unknown "asteroid" spotted by a NASA telescope is actually a comet, according to recent observations.
NASA's NEOWISE space telescope, which started its newest near-Earth object-hunting mission in 2013, spotted what scientists thought was an asteroid two times in 2013. Researchers thought it was an asteroid because it didn't appear to have a coma (a halo of fuzziness surrounding the object) or a tail — telltale signs of a comet. But all that changed with a follow-up observation.
The comet, known as C/2013 UQ4, now has a clearly visible tail. In fact, it extends for 62,000 miles (100,000 kilometers). NEOWISE spotted the comet just after it made its closest approach to the sun, causing it to become more active in July. The comet's "spectacular activity is driven by the vaporization of ice that has been preserved from the time of planet formation 4.5 billion years ago," representatives from the Jet Propulsion Laboratory, which manages the NEOWISE project for NASA, said in a statement.
In addition, astronomers have learned that the comet takes 450 years to orbit the sun, and that it moves through the solar system in the opposite direction of the planets, like a car going the wrong way down a one-way street.
NEOWISE itself is a new incarnation of the WISE (Wide-field Infrared Survey Explorer) telescope, which began its mission in 2009 by scanning the sky for asteroids, brown dwarfs (dim, failed stars), and galaxies.
As the frozen hydrogen that cooled the telescope began to run out, NASA officials decided to use the telescope to search for near-Earth objects and comets instead, and thus NEOWISE (Near-Earth Object WISE) was born. But after four months, in February 2011, the telescope was shut down and put into hibernation.
In September 2013, though, NEOWISE was awoken and given the task of searching the solar system for comets and asteroids that might threaten Earth. Its new mission is expected to last three years. During that time, the spacecraft will measure the diameters of objects that it finds, and determine their albedos (how much light they reflect).
Rainfall on Titan May Create Propane Aquifers, Study Suggests
Paul Scott Anderson - America Space
Saturn's largest moon Titan is a very alien yet eerily Earth-like world, with rain, rivers, lakes and seas; seen from above, the landscape has a familiar look to it. But those lakes, seas and rivers are fed by a different kind of rainfall – liquid methane/ethane. It is far too cold on the surface for liquid water, but the liquid hydrocarbons nicely fill in for H20 in Titan's "water cycle." Now, a new study shows how this rainfall interacts with and changes underground aquifers. The study, led by Olivier Mousis, a Cassini research associate at the University of Franche-Comté in France, suggests that runoff from rainfall is chemically altered by icy materials called clathrates within the aquifers below the surface. These aquifers, composed of propane and ethane, then feed some of the lakes and seas on the surface, although the rainfall itself is thought to initially provide the liquid in most of them.
"We knew that a significant fraction of the lakes on Titan's surface might possibly be connected with hidden bodies of liquid beneath Titan's crust, but we just didn't know how they would interact," said Mousis. "Now, we have a better idea of what these hidden lakes or oceans could be like."
The study modelled how an aquifer, or reservoir, of hydrocarbon liquids would spread through Titan's icy upper crust. The result was that a secondary reservoir, composed of clathrates, would slowly form below the original one which had been formed by rainfall.
According to Mathieu Choukroun of JPL, one of three co-authors of the study, "Our study shows that the composition of Titan's underground liquid reservoirs can change significantly through their interaction with the icy subsurface, provided the reservoirs are cut off from the atmosphere for some period of time."
How would the transformation occur? Through a process called fractionation, clathrates can split molecules into both solid and liquid phases; beneath the surface, the original clathrate reservoirs would fractionate the liquid methane, slowly changing its composition to propane or ethane.
Basically, there could be two different types of lakes/seas and rivers on Titan: those fed by underground springs would be composed of propane or ethane, while others formed from rainfall would still be composed primarily of methane.
The results provide important clues as to how the "methane cycle" on Titan works, and how it is both similar to and different from the hydrological cycle on Earth. It is worth noting also that Titan is also thought to have a liquid water ocean deeper down below the surface where it is warmer. It is unlikely that any of that water would ever make it to the surface, but like with other moons such as Europa and Enceladus, the presence of liquid water raises the prospect of possible life, at least microscopic. Some scientists even think that life could be possible in the methane lakes and seas, but it would have to be well adapted somehow to that liquid yet freezing cold environment, if it ever originated to begin with.
The new study was published in the Sept. 1, 2014 issue of the journal Icarus.
END
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