Tuesday, November 30, 2010

Searching the Heavens for Newborn Stars

SOFIA, NASA's Stratospheric Observatory for Infrared Astronomy, is ready to take off into the heavens for its first science flight this week.

Two astronomy professors, Mark Morris of the University of California at Los Angeles (UCLA), and Paul Harvey of the University of Colorado at Boulder will use the Faint Object InfraRed Camera for the SOFIA Telescope (FORCAST), a mid-spectrum infrared camera developed by Terry Herter of Cornell University, Ithaca, N.Y. to learn more about star formation from the airborne observatory.

"My primary target is the Orion nebula, which is a star formation factory," Morris said. "It's close and offers the best views of stars forming right before our very eyes."

Morris hopes to better understand the complexities of the star formation process by viewing the infrared energy emitted by warm dust in the interstellar clouds that are forming the stars. The dust is heated by the luminous, newborn stars.

"Nature doesn't form stars in isolation," he said. "It forms them in clusters, out of natal clouds that collapse under their own gravity. If you observe carefully, you start to get a clearer picture of how all the new stars are interacting with each other and with their environment."

Harvey's immediate goal is to use the unique combination of high image IR resolution available with SOFIA and FORCAST to study the distribution of dust and gas around Sharpless 140, a young, forming star cluster. Sharpless 140 lies almost 3,000 light-years from Earth in the constellation Cepheus.

"Observing the birth of stars in our own galaxy is critical, because planetary systems form at the same time that a central star is formed," Harvey said. "Some of the most luminous galaxies in the universe appear to be powered by extreme bursts of star formation."

Harvey hopes to obtain a sequence of images of the Sharpless 140 star cluster by moving the telescope slightly between each image in order to sample every sub-pixel in the image.

"We will also observe a calibration, point-like source to understand what an unresolved object looks like with the same observing technique," Harvey said. "That allows us to extract the fine details of the distribution of infrared radiation from the star cluster, and measure the luminosity of the individual stars in the cluster."

Both Morris and Harvey have flown on SOFIA's predecessor, the Kuiper Airborne Observatory, however neither will be aboard SOFIA's initial science flights due to space limitations. Instead, the two scientists will eagerly await the data gathered from FORCAST.

SOFIA is a joint program between NASA and the German Aerospace Agency, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Germany. The SOFIA program is managed at NASA's Dryden Aircraft Operations Facility, Palmdale, Calif. NASA's Ames Research Center, Moffett Field, Calif., manages the SOFIA science and mission operations in cooperation with the Universities Space Research Association (USRA), Columbia, Md., and the Deutsches SOFIA Institut (DSI), Stuttgart, Germany.

For more information visit http://www.nasa.gov/mission_pages/SOFIA/status_update_10-46F.html

Monday, November 29, 2010

NASA Scientist to Speak at Imagination Station About the Amazing Webb Telescope

A NASA research physicist working on the next generation space telescope called the James Webb Space Telescope, will be giving a presentation to visitors of the Imagination Station science center in Toledo, Ohio on Saturday, Dec. 4, 2010.

NASA's Brent Bos will give a presentation called "The James Webb Space Telescope, the First Light Machine," to visitors of the Imagination Station. Dr. Bos' presentation will be held at 11:00 a.m. EST for all Imagination Station visitors in the Extreme Science Theater. The presentation will focus on the technological advances that space exploration has taken since Hubble’s inception and what the Webb telescope will offer future exploration.

"I'm thrilled to share the excitement of the revolutionary James Webb Space Telescope Project with Imagination Station visitors," said Bos, who works at NASA's Goddard Space Flight Center, Greenbelt, Md. "I first decided that space exploration was my life's calling after a childhood visit to a museum and I hope that our presentation will inspire someone from the next generation of explorers to come and join us in the adventure."

At the time of the presentation, visitors will also be able to see pieces of items associated with the Webb telescope including the unique composite material that was created by NASA engineers to withstand the extreme environments of space, a piece of the telescope's massive sunshield and a sample of the "microshutter." Visitors will also receive a unique bookmark that explains a star's life cycle.

The event ties in with NASA’s traveling museum exhibition, New Views of the Universe which is currently at the Imagination Station museum and runs until January 16, 2011. The exhibit immerses visitors in the mystery and magnificence of the Hubble Space Telescope mission and introduces them to Hubble’s successor, the James Webb Space Telescope.

"Imagination Station is a science center dedicated to inspiring in children the wonder of science," said Anna Kolin, Communications and Public Relations Manager for the museum. "We're thrilled to be offering our community the opportunity to see Hubble's legacy and what the future holds for space exploration with the James Webb Space Telescope."

The 2,000 square-foot exhibit immerses visitors in the magnificence and mystery of the Hubble mission and introduces the James Webb Space Telescope. A scale model of the Hubble is the focal point of the installation. "Satellite" units incorporate hands-on activities about how the telescope works, and feature Hubble's contributions to the exploration of planets, stars, galaxies, and the universe.

The exhibit contains images and data taken by Hubble of planets, galaxies, regions around black holes, and many other fascinating cosmic entities. The exhibit is comprised of backlit color images and numerous interactive displays. Using a computer, visitors will be able to "hit" Jupiter with a comet and attempt to put star clusters in order of age. Using an infrared camera, visitors can also learn about the different wavelengths of light by taking pictures of their hand in visible and infrared light.

Visitors will learn about the James Webb Space Telescope, the next-generation premier space observatory, exploring deep space phenomena from distant galaxies to nearby planets and stars. The Webb Telescope will give scientists clues about the formation of the universe and the evolution of our own solar system, from the first light after the Big Bang to the formation of star systems capable of supporting life on planets like Earth.

Through computer games, videos and displays, visitors will also be able to experience how the Webb telescope will work. Visitors will learn about the cutting-edge technology of the Webb telescope like one that will see the universe in infrared light. All the new technology will enable scientists to see far back in time to when galaxies first formed and make many scientific breakthroughs.

The Imagination Station, located on the downtown Toledo riverfront, is a science center dedicated to delivering science and technology based programming to youth and their families throughout Northwest Ohio and Southeast Michigan. All activities are included in the cost of admission. Imagination Station is located at One Discovery Way, Toledo, Ohio, 43604. For more information, please call 419-244-2674 or visit imaginationstationtoledo.org.

The Webb telescope project is managed at NASA's Goddard Space Flight Center in Greenbelt, Md. The telescope is a joint project of NASA, the European Space Agency and the Canadian Space Agency.

For more information visit http://www.nasa.gov/topics/people/features/Brent_Bos.html

Sunday, November 28, 2010

Expedition 25 Landing

The Soyuz TMA-19 spacecraft with Expedition 25 Commander Doug Wheelock and Flight Engineers Shannon Walker and Fyodor Yurchikhin touches down near the town of Arkalyk, Kazakhstan on Friday, Nov. 26, 2010. Russian Cosmonaut Yurchikhin and NASA Astronauts Wheelock and Walker, are returning from six months onboard the International Space Station where they served as members of the Expedition 24 and 25 crews.

For more information visit http://www.nasa.gov/multimedia/imagegallery/image_feature_1809.html

Thursday, November 25, 2010

GOES-13 Looks at Thanksgiving Travel Conditions, Sees No Tropical Cyclones

The GOES-13 satellite captured a look at the cloud cover and weather systems around the U.S. on Nov. 24 as Thanksgiving travelers make their way to their holiday celebrations. With six days left in the Atlantic and Eastern Pacific Ocean hurricane season there is not a tropical cyclone in sight.

The Geostationary Operational Environmental Satellite (GOES) series of satellites are operated by the National Oceanic and Atmospheric Administration. NASA's GOES Project, located at NASA's Goddard Space Flight Center, Greenbelt, Md. creates some of the satellite images and animations from the GOES satellites.

The GOES-13 satellite captured an image of North America on Wednesday, November 24 at 1445 UTC (9:45 a.m. EST) showing a large area of cloud cover stretching from the Gulf coast north into the upper Midwest. That cloud cover is associated with a warm front that stretches from the Tennessee Valley west to Kansas where an associated low pressure area is located.

Residents the in the Tennessee and Ohio valleys can expect rain from that system, and severe storms are possible in Missouri, northern Arkansas and eastern Kansas and eastern Oklahoma today.

Ahead of the large blanket of cloud cover, high pressure is currently keeping the U.S. east coast in sunshine, but that will change as the clouds track east by Thanksgiving Day.

Behind the blanket of cloud cover appears to be a long line of clouds from south to north that resembles an exclamation mark. Those are clouds associated with a front that's bringing snow to Minnesota, the Dakotas, western Montana, Wyoming, Colorado, northern Arizona and eastern Utah today. Snows in North Dakota and the Colorado Rockies may be heavy.

To the west of that line of clouds there is a high pressure system centered over northern Nevada which will bring mostly clear conditions to Washington, Oregon, Idaho, Nevada, and California.

For more information visit http://www.nasa.gov/mission_pages/hurricanes/features/GOESThanksgiving.html

Wednesday, November 24, 2010

Stripes are Back in Season on Jupiter

New NASA images support findings that one of Jupiter's stripes that "disappeared" last spring is now showing signs of a comeback. These new observations will help scientists better understand the interaction between Jupiter's winds and cloud chemistry.

Earlier this year, amateur astronomers noticed that a longstanding dark-brown stripe, known as the South Equatorial Belt, just south of Jupiter's equator, had turned white. In early November, amateur astronomer Christopher Go of Cebu City, Philippines, saw an unusually bright spot in the white area that was once the dark stripe. This phenomenon piqued the interest of scientists at NASA's Jet Propulsion Laboratory, Pasadena, Calif., and elsewhere.

After follow-up observations in Hawaii with NASA's Infrared Telescope Facility, the W.M. Keck Observatory and the Gemini Observatory telescope, scientists now believe the vanished dark stripe is making a comeback.

"The reason Jupiter seemed to 'lose' this band – camouflaging itself among the surrounding white bands – is that the usual downwelling winds that are dry and keep the region clear of clouds died down," said Glenn Orton, a research scientist at JPL. "One of the things we were looking for in the infrared was evidence that the darker material emerging to the west of the bright spot was actually the start of clearing in the cloud deck, and that is precisely what we saw."

This white cloud deck is made up of white ammonia ice. When the white clouds float at a higher altitude, they obscure the missing brown material, which floats at a lower altitude. Every few decades or so, the South Equatorial Belt turns completely white for perhaps one to three years, an event that has puzzled scientists for decades. This extreme change in appearance has only been seen with the South Equatorial Belt, making it unique to Jupiter and the entire solar system.

The white band wasn't the only change on the big, gaseous planet. At the same time, Jupiter's Great Red Spot became a darker red color. Orton said the color of the spot – a giant storm on Jupiter that is three times the size of Earth and a century or more old – will likely brighten a bit again as the South Equatorial Belt makes its comeback.

The South Equatorial Belt underwent a slight brightening, known as a "fade," just as NASA's New Horizons spacecraft was flying by on its way to Pluto in 2007. Then there was a rapid "revival" of its usual dark color three to four months later. The last full fade and revival was a double-header event, starting with a fade in 1989, revival in 1990, then another fade and revival in 1993. Similar fades and revivals have been captured visually and photographically back to the early 20th century, and they are likely to be a long-term phenomenon in Jupiter's atmosphere.

Scientists are particularly interested in observing this latest event because it's the first time they've been able to use modern instruments to determine the details of the chemical and dynamical changes of this phenomenon. Observing this event carefully may help to refine the scientific questions to be posed by NASA's Juno spacecraft, due to arrive at Jupiter in 2016, and a larger, proposed mission to orbit Jupiter and explore its satellite Europa after 2020.

The event also signifies another close collaboration between professional and amateur astronomers. The amateurs, located worldwide, are often well equipped with instrumentation and are able to track the rapid developments of planets in the solar system. These amateurs are collaborating with professionals to pursue further studies of the changes that are of great value to scientists and researchers everywhere.

"I was fortunate to catch the outburst," said Christopher Go, referring to the first signs that the band was coming back. "I had a meeting that evening and it went late. I caught the outburst just in time as it was rising. Had I imaged earlier, I would not have caught it," he said. Go, who also conducts in the physics department at the University of San Carlos, Cebu City, Philippines, witnessed the disappearance of the stripe earlier this year, and in 2007 he was the first to catch the stripe's return. "I was able to catch it early this time around because I knew exactly what to look for."

NASA's Exoplanet Science Institute at the California Institute of Technology in Pasadena manages time allocation on the Keck telescope for NASA. Caltech manages JPL for NASA.

For more information visit http://www.nasa.gov/topics/solarsystem/features/jupiter20101124.html

Tuesday, November 23, 2010

Technicians Use Scanners to Survey External Tank

A couple kinds of high-tech devices and steady nerves by technicians have been called on to carefully survey the external fuel tank of space shuttle Discovery as it sits on Launch Pad 39A at NASA's Kennedy Space Center in Florida.

The scans are expected to be finished sometime Wednesday, giving Space Shuttle Program managers additional information they need to help decide whether Discovery is ready to launch on the STS-133 mission to the International Space Station. The mission is to launch no earlier than Dec. 3.

Specialists using two forms of imagers are examining the stringers that make up the ribbed intertank section of the external tank. There are 108 of the 21-foot-long metal stringers that connect the cone-shaped liquid oxygen tank on top with the oblong liquid hydrogen tank on the bottom.

Technicians are looking for cracks or other flaws in the aluminum alloy material that makes up the intertank. They have to use scanners because all of the tank's metal has been covered with a thick layer of foam insulation to help keep the super-cold propellants chilled and protect the structure from aerodynamic environments during ascent.

At their disposal are backscatter devices that bounce radiation off the tank and computing radiography scanners that work like an X-ray machine by transmitting radiation through the tank's foam and metal skin.

"It's pretty straightforward," said Alicia Mendoza, NASA's External Tank and Solid Rocket Booster vehicle manager at Kennedy. "It's been pretty efficient, actually."

Four cracks were found in two of the stringers after the tank was partially filled during a scrubbed countdown on Nov. 5. The cracks in the stringers cracked a section of foam on the outside of the tank. The cracked stringers have been replaced and reinforced with "doublers," which are shaped metal pieces twice as thick as the original stringer. Also, the latest scans show no signs of damage in the tank's other stringers.

Mendoza recalls the scrubbed launch when she saw the foam piece dislodged.

"The first thing that comes to mind is, what caused it, how do we fix it and how do we go forward," she said.

Since then, she and a team of NASA and contractors have been working around the clock at Kennedy and NASA's other spaceflight centers to find out about the cracks and repair them.

The information from the scans is being reviewed by officials at NASA's Marshall Space Flight Center in Huntsville, Ala., where the tank was designed, and at NASA's Michoud Assembly Facility outside New Orleans where the tank was built.

The stringers on the part of the tank facing Discovery are under the most scrutiny because foam breaking off in that area could pose a potential threat to the shuttle's heat shielding.

Getting to all the stringers facing Discovery is a challenge. Working some 15 stories above the launch platform, technicians venture out on platforms to set up the scanners carefully. Surveying the stringers directly between the tank and the shuttle means working on a platform that is 18-inches at its widest point.

For the computing radiography machine, the one that works like an X-ray, a technician also climbs inside the intertank area to place the film for the image. The backscatter machine picks up the reflected energy on its own.

Because the examination is so important, neither process is particularly quick. It takes the backscatter scanner about 90 minutes to survey a single stringer. The computing radiography scanner can do up to five stringers in an hour.

"They definitely have to be meticulous with the angle, with the shot," Mendoza said.

The external tank is the largest single part of the shuttle when it is stacked for launch. Although it has no engines of its own, it provides about 535,000 gallons of propellants to the shuttle’s three main engines. The tank's machinery includes a series of valves and sensors that have to function perfectly before a liftoff is allowed.

The tank also undergoes changes as it is loaded with its propellants. At minus-423 degrees and minus-297 degrees respectively, the liquid hydrogen and liquid oxygen that fill the tank are some of the coldest materials on Earth. The tank's diameter shrinks about an inch when the propellants are loaded. Likewise, if the tank has to be emptied for a scrub, as happened Nov. 5, the tank expands as it warms up to Florida's outdoor temperature.

Managers expect the two high-tech tank scanners will help provide them with information that will support Discovery’s next launch opportunity.

For more information visit http://www.nasa.gov/mission_pages/shuttle/behindscenes/etscan.html

Monday, November 22, 2010

NASA Spacecraft Burns for Another Comet Flyby

Eighty-six days out from its appointment with a comet, NASA's Stardust
spacecraft fired its thrusters to help refine its flight path. The Stardust-NExT mission will fly
past comet Tempel 1 next Valentine's Day (Feb. 14, 2011). It will perform NASA's second comet flyby within four months.

"One comet down, one to go," said Tim Larson, project manager for both the Stardust-NExT mission and the EPOXI mission -- which successfully flew past comet Hartley 2 on Nov. 4.

The trajectory correction maneuver, which adjusts the spacecraft's flight path, began at 2 p.m. EST (11:00 a.m. PST) on Nov. 20. The Stardust spacecraft's rockets fired for 9 seconds, consumed about 41 grams (1.4 ounces) of fuel and changed the spacecraft's speed by all of 0.33 meters per second (about 0.7 miles per hour). The maneuver was designed to target a point in space 200 kilometers (124 miles) from comet Tempel 1.

Launched on Feb. 7, 1999, Stardust became the first spacecraft in history to collect samples
from a comet (comet Wild 2), and return them to Earth for study. While its sample return capsule parachuted to Earth in January 2006, mission controllers were placing the still viable spacecraft on a path that would allow NASA the opportunity to re-use the already-proven flight system if a target of opportunity presented itself. In January 2007, NASA re-christened the mission "Stardust-NExT" (New Exploration of Tempel), and the Stardust team began a four-and-a-half year journey for the spacecraft to comet Tempel 1. This will be the second exploration of Tempel 1 by a spacecraft (Deep Impact).

Along with the high-resolution images of the comet's surface, Stardust-NExT will also measure
the composition, size distribution and flux of dust emitted into the coma, and provide
important new information on how Jupiter family comets evolve and how they formed 4.6 billion years ago.

Stardust-NExT is a low-cost mission that will expand the investigation of comet Tempel 1
initiated by NASA's Deep Impact spacecraft. JPL, a division of the California Institute of
Technology in Pasadena, manages Stardust-NExT for the NASA Science Mission Directorate,
Washington, D.C. Joe Veverka of Cornell University, Ithaca, N.Y., is the mission's principal
investigator. Lockheed Martin Space Systems, Denver, built the spacecraft and manages
day-to-day mission operations.

For more information visit http://www.jpl.nasa.gov/news/news.cfm?release=2010-390

Sunday, November 21, 2010

NASA Engineer to Blog about Upgrades at McMurdo Station

What are you doing for the holidays this winter? Spending time with family and friends?

More than a dozen Near Earth Network engineers and support personnel from NASA’s Goddard Space Flight Center in Greenbelt, Md., and Wallops Flight Facility in Va., will be packing their bags and spending their holidays far away from their families at McMurdo Station, Antarctica, for the austral summer.

McMurdo Station is one of three permanent National Science Foundation (NSF) stations in Antarctica. At McMurdo Station, which is the main U.S. station in Antarctica and 850 miles (1,360 km) north of the South Pole, the mean annual temperature is 0 F (-18 C). Temperatures can reach 46 F (8 C) in the austral summer and -58 F (-50 C) in the austral winter. The average wind is 14 miles per hour, but winds have exceeded 115 miles per hour.

The team will perform crucial upgrades and maintenance activities to the NASA Near Earth Network at McMurdo Ground Station .

in support of European Space Agency’s latest meteorological satellite, MetOp, which launched in October 2006. MetOp-A is the first in a series of three European meteorological operational satellites procured by ESA to serve as the space segment of the European Organisation for the Exploitation of Meteorological Satellites' EUMETSAT Polar System. Under a memorandum of agreement between NASA and the National Oceanic and Atmospheric Administration , the McMurdo Ground Station’s support will begin in March 2011 and also will support MetOp-B and C over the next 15 years.

In collaboration with the NSF, NASA owns and operates a single 10-meter antenna, hidden inside the radome in this photo, and associated electronics equipment that has provided countless hours of space-to-ground communications support to dozens of Expendable Launch Vehicles and polar-orbiting satellites owned by NASA, other government agencies and international partners.

In addition to having a station at McMurdo, the Near Earth Network combines other NASA-owned stations with services purchased from commercially owned stations to provide support to a long list of missions.

The upgrades will involve replacing a majority of the electronics systems in the ground station. The maintenance of the antenna system will involve using a crane to uncap the radome, disassemble the antenna and replace the antenna pedestal followed by reassembly of the antenna and radome. These activities will allow the Near Earth Network to support not only MetOP but also a host of other future missions.

Goddard engineer Kevin McCarthy will lead this effort, providing project oversight and coordination with the National Science Foundation. In addition to reporting to Goddard and the Space Communications and Navigation Program on day-to-day activities and status, he will be the primary blogger for the Near Earth Network McMurdo upgrades while in Antarctica.

“I’m looking forward to my departure on Nov. 6 and my scheduled return home on Feb. 5, 2011, as well as sharing my team’s experiences with you on our work and life at McMurdo,” reports McCarthy.

The Near Earth Network is the latest NASA project to join the rising trend of blogging on day- to-day activities as part of NASA’s blog website under the title of “Summer on the Ice,” which will be updated regularly with news and photos of the site upgrades.

For more information visit http://www.nasa.gov/topics/earth/features/mcmurdo-blog.html

Thursday, November 18, 2010

Profiling the Largest Solar Explosions

Solar flares – they're big and they're fast. They can knock out a satellite or create a beautiful aurora. And the jury is still out on what causes these explosions.

Flares, and the related coronal mass ejection, shoot energy, radiation, and magnetic fields out into space that can harm satellites or humans in space. Current observations aren't precise enough to determine whether the eruptions are driven by energy surging through the sun's surface, or by the sudden release of energy that has slowly accumulated in the atmosphere.

Now, a new way of looking at old data has changed all that, but the results have created more mystery: There isn't enough energy passing through the surface during the eruption to drive the explosion.

"In some sense, the idea that energy from below triggers the eruption is the easiest explanation – like a geyser," says Peter Schuck, a physicist who studies space weather at NASA's Goddard Space Flight Center in Greenbelt, Md. "But if the idea doesn't agree with what's observed, then it's wrong. End of story."

Schuck's research indicates that, instead, the trigger occurs in the sun's atmosphere. "Our result shows that observations are more consistent with a slow accumulation of energy in the atmosphere," Schuck said, "and then a sudden explosion triggered from above, more like lightning."

Schuck studies coronal mass ejections, or CMEs, and solar flares at the place where theory and observation overlap. His latest work on CMEs appeared in the Astrophysical Journal on May 1. Schuck constructed a way to test CME and flare observations in order to limit which group of hypotheses fit the data, even when there's not enough evidence to conclusively pick a single theory.

In the case of CMEs, the data is limited to distant movies captured by spacecraft such as the Solar and Heliospheric Observatory (SOHO). These movies show that CMEs begin as a gigantic arch, some 50 times larger than Earth, with each of its feet planted on the sun's surface, or "photosphere."

Two broad camps of theories have been developed to explain these so-called coronal loops. "The energy is built up by either a twisting motion below the surface or the release of magnetic energy in the solar atmosphere," says Haimin Wang, a physicist at the New Jersey Institute of Technology, whose work focuses on the characteristics of the photosphere before and during solar ejections.

Either way, the energy originally comes from the surface. The question is simply whether it surges through directly before the appearance of the coronal loop or oozes up slowly over time, storing up in the atmosphere until released in a massive explosion of light, plasma, magnetic fields and high energy particles.

Distinguishing between the two options based solely on a distant movie isn't easy. Imagine trying to figure out what powers a car when all you've got to go on is a movie of a highway. Worse, that movie isn't from above, so you might easily determine the direction and speed of those cars, but from head-on or a side view where you're not even sure of the angle.

If, however, you can infer the speed of the car, you could at the very least figure out how much energy it has and, in turn, rule out any power source that didn't jibe with what you saw.

Schuck has done exactly that. "I developed a way to infer magnetic field motion, and therefore energy amounts, from the velocities we observe in the photosphere," he says.

Imagine the cars again. If the cars were coming directly toward you, you could measure the wavelength of the headlights and by determining how strongly they'd been shifted by the Doppler effect (that same wave-changing effect that causes sirens to sound higher as they come toward you and lower as they move away) you could measure the car's speed.

Schuck used similar, head-on Doppler measurements to find the velocity of solar material on the surface of the sun. This material moves perpendicular to the magnetic field at the base of the coronal loop -- the crux of what Schuck is trying to understand. He can convert those initial velocities of the sun's surface into information about the motion and energy of the magnetic field. This analysis may not spit out an exact number for the energy, but it does give a precise, accurate range of energy possibilities.

And so, for the first time, one can look at images of the sun and set firm limits on the maximum energy at a given spot – at least if the material was moving directly towards the camera to provide an accurate Doppler measurement.

The next step applies the analysis to an actual coronal mass ejection. Schuck looked at the data from a CME on September 12, 2000. This was an M-class ejection -- meaning it was fairly intense, but one step below the strongest X-class -- that moved directly towards Earth. Conveniently, this was also a well-studied flare, so other scientists had already examined SOHO images to measure the path, speed, and energy of the CME. This information, in turn, implies how much energy would have come through the photosphere at the start of the process had it indeed initiated from below.

The results were dramatic. The SOHO images showed the photosphere moving at speeds 10,000 times less slowly than would have been expected if it were directly triggering the eruption. "The velocity you'd need to see on the photosphere would be a thousand kilometers per second," says Shuck. "Not only are these speeds easily detected but they would be greater than the standard measurement range of the instrument. You'd see really weird stuff in the data readouts."

There is always the slim chance that somehow the instruments didn't catch the extreme motion, but given how large the velocities would have had to be, Schuck thinks this is unlikely.

This still leaves a variety of theories on just how the energy is stored and what triggers its release in the atmosphere. Distinguishing between those theories will require more detailed data—something scientists hope NASA’s Solar Dynamics Observatory, launched in February 2010 will be able to provide.

Unlike previous missions, SDO will be able to directly measure the energy in the photosphere – as opposed to Schuck's present method of inferring that energy from velocity measurements -- and it will do so with 20 times the resolution of the data on which Schuck based his current work. Such information will help narrow down what triggers a CME or solar flare even more precisely.

"Now we just need some really big CMEs to work with," says Schuck.

For more information visit http://www.nasa.gov/topics/solarsystem/sunearthsystem/main/solar-explosions.html

Tuesday, November 16, 2010

It's a Bird, It's a Missile... It's an Airplane!

When Patrick Minnis saw video of the "mystery" contrail Nov. 9 that looked like a missile launch near Catalina Island off Los Angeles, he figured it the way most people did.

"I assumed it was a missile," said Minnis, a contrail expert in the Science Directorate at NASA's Langley Research Center in Hampton, Va.

Then he got a call from an Associated Press reporter and told her, yes, it sure looks like a missile.

"She responded with links to two different blogs that compared it to older aircraft contrail pictures, and indicated that the blog authors thought it was an aircraft contrail," Minnis recalls. "I had not really thought about that aspect previously and, at first glance, the video showed what looked like a missile launch. Once the idea that it was an aircraft contrail entered my head, I had to pay closer attention, because aircraft contrails are part of my job description."

Minnis usually studies contrails to determine their effect on Earth's climate. He and others have discovered that airplane contrails create cirrus clouds on days they wouldn't usually exist. Because of this, he calculates, the cirrus-cloud cover over the United States is increasing by one percent each decade and contributing to global warming by blocking the release of heat from the planet.

Using Satellites

Minnis applied his years of research experience – and a little detective work - to the contrail mystery by examining the video again.

"It appeared to be between two high clouds, one in foreground and one in the background," he said. "I would have expected that it was at the same level or above the high clouds, so it should have been obscured more by the cloud in the background. Thus, I concluded again that it was a missile."

He took another look, this time with the help of Doug Spangenberg, who works at Langley as part of the Science Systems and Applications Inc. (SSAI) contract. Spangenberg had sequenced imagery from the Geostationary Operational Environmental Satellite 11 (GOES-11) that showed a persistent contrail that could match the "mystery" contrail.

Minnis then consulted a contrail "forecaster" put together by SSAI's David Duda and Rabindra Palikonda, who also work at Langley, and learned that conditions were "ripe" for persistent contrails over the Pacific west of Los Angeles, but that contrails would only survive for a short time closer to the coast.

"As it turns out, the high clouds seen in the background of the video were actually behind the contrail because the plane had flown north of the clouds," Minnis said, "and changed course to the northeast, so that the clouds were behind the contrail as viewed from Catalina Island. All of that information changed my mind."

Minnis said that while he can't prove the contrail came from an airplane, it is the "most likely" scenario based on his research.

"Later, while viewing some blogs, I found that the contrail corresponded remarkably well with flight AWE808, which flew from Hawaii to Phoenix; it showed the change in course to the northeast at the same location, further confirming my conclusion."

For more information visit http://www.nasa.gov/topics/earth/features/mystery-contrail.html

Sunday, November 14, 2010

Hundreds Tour Kennedy on Two Wheels

Hundreds of bicyclists mingled with spacecraft Oct. 23 as Kennedy employees, family and guests pedaled around the center for the second Tour de KSC.

Grouped by speed and skill levels, some riders covered all the landmarks Kennedy has to offer, including the Vehicle Assembly Building, both shuttle launch pads and the Shuttle Landing Facility. Plenty of stops along the way offered employees and their guests photo ops with space shuttle Discovery on Launch Pad 39A.

In all, 681 people rode their bikes onto the space center for the event, said Dicksy Hansen, chair of Combined Federal Campaign or CFC.

" We had a range of those employees who haven’t been on a bike for years up to very talented cyclists who cycle passionately," Hansen said. "There were beach cruisers, recumbents, touring, and racing bikes. Some people were dressed in cycling gear and others dressed in regular, every day clothes. There was even an 18th Century style bicycle with a very large rear wheel and small front wheel. This made the event even more diverse and entertaining."

The entry fee for each person included a donation to the CFC and organizers of this year's event were able to contribute $10,215 to the annual fundraising drive. Riders also received a T-shirt.

"We increased our CFC donation from $5 to $15 a ticket which increased our donation from $2,500 last year to $10,000 this year," Hansen said.

Center Director Bob Cabana, a former astronaut and avid cyclist, led a group out from the Kennedy Space Center Visitor Complex then up to the VAB.

"I believe that there is a variety of reasons folks come out," Hansen said. "Some because they love cycling and KSC so it is a great day for them when the two come together. Other folks just enjoy coming out to KSC and bringing their guests to view the Center. There aren’t very many opportunities for employees to bring guests on Center. Others wanted to support CFC and contribute by enjoying a few hours cycling around the Center."

Last year's inaugural event also opened the CFC season. This was the second Tour de KSC, but will not be the last, Hansen said. Each event takes considerable planning and Hansen's group already anticipates holding the third event next year.

For more information visit http://www.nasa.gov/centers/kennedy/news/tourdeksc2010.html

Friday, November 12, 2010

Sunspot 1123 Hurls Filament toward Earth


Coronagraph images from the Solar and Heliospheric Observatory (SOHO) and NASA's twin STEREO spacecraft show a faint coronal mass ejection emerging from the blast site and heading off in a direction just south of the sun-Earth line.

The cloud could deliver a glancing blow to Earth's magnetic field sometime on Nov. 14th or 15th. High latitude sky watchers should be alert for auroras on those dates.

For more information visit http://www.nasa.gov/topics/solarsystem/sunearthsystem/main/News111210-c4flare.html

Thursday, November 11, 2010

Shedding 'Bent' Light on Dark Matter

Astronomers using NASA's Hubble Space Telescope took advantage of a giant cosmic magnifying glass to create one of the sharpest and most detailed maps of dark matter in the universe. Dark matter is an invisible and unknown substance that makes up the bulk of the universe's mass. Astronomer Dan Coe led the research while working at NASA's Jet Propulsion Laboratory in Pasadena, Calif.; he is currently with the Space Telescope Science Institute in Baltimore, Md.

The astronomers used Hubble to chart the invisible matter in the massive galaxy cluster Abell 1689, located 2.2 billion light-years away. The cluster's gravity, the majority of which comes from dark matter, acts like a cosmic magnifying glass, bending and amplifying the light from distant galaxies behind it. This effect, called gravitational lensing, produces multiple, warped, and greatly magnified images of those galaxies, like the view in a funhouse mirror. By studying the distorted images, astronomers estimated the amount of dark matter within the cluster.

The new dark matter observations may yield new insights into the role of dark energy in the universe's early formative years. A mysterious property of space, dark energy fights against the gravitational pull of dark matter. The new results suggest that galaxy clusters may have formed earlier than expected, before the push of dark energy inhibited their growth. Dark energy pushes galaxies apart from one another by stretching the space between them, suppressing the formation of giant structures called galaxy clusters. One way astronomers can probe this primeval tug-of-war is by mapping the distribution of dark matter in clusters.

For more information visit http://www.jpl.nasa.gov/news/news.cfm?release=2010-382

Wednesday, November 10, 2010

Sensor on Mars Rover to Measure Radiation Environment

About eight months before the NASA rover Curiosity touches down on Mars in August 2012, the mission's science measurements will begin much closer to Earth.

The Mars Science Laboratory mission's Radiation Assessment Detector, or RAD, will monitor naturally occurring radiation that can be unhealthful if absorbed by living organisms. It will do so on the surface of Mars, where there has never before been such an instrument, as well as during the trip between Mars and Earth.

RAD's measurements on Mars will help fulfill the mission's key goals of assessing whether Curiosity's landing region on Mars has had conditions favorable for life and for preserving evidence about life. This instrument also will do an additional job. Unlike any of the nine others in this robotic mission's science payload, RAD has a special task and funding from the part of NASA that is planning human exploration beyond Earth orbit. It will aid design of human missions by reducing uncertainty about how much shielding from radiation future astronauts will need. The measurements between Earth and Mars, as well as the measurements on Mars, will serve that purpose.

"No one has fully characterized the radiation environment on the surface of another planet. If we want to send humans there, we need to do that," said RAD Principal Investigator Don Hassler of the Boulder, Colo., branch of the Southwest Research Institute.

Whether the first destination for human exploration beyond the moon is an asteroid or Mars, the travelers will need protection from the radiation environment in interplanetary space. Hassler said, "The measurements we get during the cruise from Earth to Mars will help map the distribution of radiation throughout the solar system and be useful in mission design for wherever we send astronauts."

RAD will monitor high-energy atomic and subatomic particles coming from the sun, from distant supernovas and from other sources. These particles constitute the radiation that could be harmful to any microbes near the surface of Mars or to astronauts on a Mars mission. Galactic cosmic rays, coming from supernova explosions and other events extremely far from our own solar system, are a variable shower of charged particles. In addition, the sun itself spews electrons, protons and heavier ions in "solar particle events" fed by solar flares and ejections of matter from the sun's corona. Astronauts might need to move into havens with extra shielding on an interplanetary spacecraft or on Mars during solar particle events.

Earth's magnetic field and atmosphere provide effective shielding for our home planet against the possible deadly effects of galactic cosmic rays and solar particle events. Mars, though, lacks a global magnetic field and has only about one percent as much atmosphere as Earth. Just to find high-enough radiation levels on Earth for checking and calibrating RAD, the instrument team needed to put it inside major particle-accelerator research facilities in the United States, Europe, Japan and South Africa.

An instrument on NASA's Mars Odyssey orbiter, which reached Mars in 2001, assessed radiation levels above the Martian atmosphere. Current estimates of the radiation environment at the planet's surface rely on modeling of how the thin atmosphere affects the energetic particles, but uncertainty in the modeling remains large. "A single energetic particle hitting the top of the atmosphere can break up into many particles -- a cascade of lower-energy particles that might be more damaging to life than a single high-energy particle," Hassler noted.

The 1.7-kilogram (3.8-pound) RAD instrument has an upward-pointing, wide-angle telescope with detectors for charged particles with masses up to that of iron. It can also detect secondary neutrons coming from both the Mars atmosphere above and Mars surface material below. Hassler's international RAD team includes experts in instrument design, astronaut safety, atmospheric science, geology and other fields.

Southwest Research Institute, in Boulder and in San Antonio, Texas, and Christian Albrechts University, in Kiel, Germany, built RAD with funding from the NASA Exploration Systems Mission Directorate and Germany's national aerospace research center: Deutschen Zentrum für Luft- und Raumfahrt. The team assembling and testing the Mars Science Laboratory spacecraft at NASA's Jet Propulsion Laboratory in Pasadena, Calif., installed RAD onto Curiosity last month for the late-2011 launch.

RAD measurements during the trip from Earth to Mars will enable correlations with instruments on other spacecraft that monitor solar particle events and galactic cosmic rays in Earth's neighborhood, then will yield data about the radiation environment farther from Earth.

Once on Mars, the rover's prime mission will last a full Martian year -- nearly two Earth years. A one-time set of measurements by RAD would not suffice for determining the radiation environment on the surface, because radiation levels vary on time frames both longer than a year and shorter than an hour. Operational planning for Curiosity anticipates that RAD will record measurements for 15 minutes of every hour throughout the prime mission.

Radiation levels probably make the surface of modern Mars inhospitable for microbial life. The measurements from RAD will feed calculations of how deeply a possible future robot on a life-detection mission might need to dig or drill to reach a microbial safe zone. For assessing whether the surface radiation environment could have been hospitable for microbes in Mars' distant past, researchers will combine RAD's measurements with estimates of how the activity of the sun and the atmosphere of Mars have changed in the past few billion years.

"The primary science goal of Curiosity is to determine whether its landing site is, or ever was, a habitable environment, a place friendly to life," said JPL's Ashwin Vasavada, deputy project scientist for the Mars Science Laboratory. "That involves looking both for conditions that would support life as well as for those that would be hazardous to life or its chemical predecessors. Natural, high-energy radiation is just such a hazard, and RAD will give us the first look at the present level of this radiation and help us to better estimate radiation levels throughout Mars' history."

JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Science Laboratory Project for NASA's Science Mission Directorate, Washington.

For more information visit http://www.nasa.gov/mission_pages/msl/news/msl20101109.html

Tuesday, November 9, 2010

Cool Star is a Gem of a Find

NASA's Wide-field Infrared Survey Explorer, or WISE, has eyed its first cool brown dwarf: a tiny, ultra-cold star floating all alone in space.

WISE is scanning the whole sky in infrared light, picking up the glow of not just brown dwarfs but also asteroids, stars and galaxies. It has sent millions of images down to Earth, in which infrared light of different wavelengths is color-coded in the images.

"The brown dwarfs jump out at you like big, fat, green emeralds," said Amy Mainzer, the deputy project scientist of WISE at NASA's Jet Propulsion Laboratory in Pasadena, Calif. Mainzer, who makes jewelry in her spare time, explained that the brown dwarfs appear like green gems in WISE images because the methane in their atmospheres absorbs the infrared light that has been coded blue, and because they are too faint to give off the infrared light that is color-coded red. The only color left is green.

Like Jupiter, brown dwarfs are made up of gas -- a lot of it in the form of methane, hydrogen sulfide, and ammonia. These gases would be deadly to humans at the concentrations found around brown dwarfs. And they wouldn't exactly smell pretty.

"If you could bottle up a gallon of this object's atmosphere and bring it back to Earth, smelling it wouldn't kill you, but it would stink pretty badly -- like rotten eggs with a hint of ammonia," said Mainzer.

Mainzer and other members of the WISE team are already accumulating a quarry of brown dwarf candidates similar to this one. Brown dwarfs have masses somewhere between those of a star and a planet. They start out like stars as collapsing balls of gas, but they lack the mass to fuse atoms together at their core and shine with starlight. As time goes on, these lightweights cool off, until they can only be seen in infrared light. There could be many such objects lurking in the neighborhood of our sun, but astronomers know of only a handful so far. WISE is expected to find hundreds, including the coolest and closest of all.

To scientists, brown dwarfs represent the perfect laboratories for studying planet-like atmospheres.

"They're a great test of our understanding of atmospheric physics of planets, since they don't have solid surfaces, and there's no big, bright sun to get in the way," said co-author Michael Cushing, a postdoctoral fellow at JPL.

WISE's new brown dwarf is named WISEPC J045853.90+643451.9 for its location in the sky. It is estimated to be 18 to 30 light-years away and is one of the coolest brown dwarfs known, with a temperature of about 600 Kelvin, or 620 degrees Fahrenheit. That's downright chilly as far as stars go. The fact that this brown dwarf jumped out of the data so easily and so quickly -- it was spotted 57 days into the survey mission -- indicates that WISE will discover many, many more. The discovery was confirmed by follow-up observations at the University of Virginia's Fan Mountain telescope, the Large Binocular Telescope in southeastern Arizona, and NASA's Infrared Telescope Facility on Mauna Kea, Hawaii. The results are in press at the Astrophysical Journal.

For more information visit http://www.jpl.nasa.gov/news/news.cfm?release=2010-377

Monday, November 8, 2010

What Will Webb See? Supercomputer Models Yield Sneak Previews

As scientists and engineers work to make NASA's James Webb Space Telescope a reality, they find themselves wondering what new sights the largest space-based observatory ever constructed will reveal. With Webb, astronomers aim to catch planets in the making and identify the universe's first stars and galaxies, yet these are things no telescope -- not even Hubble -- has ever shown them before.

"It's an interesting problem," said Jonathan Gardner, the project's deputy senior project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "How do we communicate the great scientific promise of the James Webb Space Telescope when we've never seen what it can show us?"

So the project turned to Donna Cox, who directs the Advanced Visualization Laboratory (AVL) at the National Center for Supercomputing Applications (NCSA). Located at the University of Illinois in Urbana-Champaign, NCSA provides enormous computing resources to researchers trying to simulate natural processes at the largest and smallest scales, from the evolution of the entire universe to the movement of protein molecules through cell walls.

Cox and her AVL team developed custom tools that can transform a model's vast collection of ones and zeroes into an incredible journey of exploration. "We take the actual data scientists have computed for their research and translate them into state-of-the-art cinematic experiences," she said.

Armed with an ultra-high-resolution 3D display and custom software, the AVL team choreographs complex real-time flights through hundreds of gigabytes of data. The results of this work have been featured in planetariums, IMAX theaters and TV documentaries. "Theorists are the only scientists who have ventured where Webb plans to go, and they did it through complex computer models that use the best understanding of the underlying physics we have today," Cox said. "Our challenge is to make these data visually understandable -- and reveal their inherent beauty."

The new visualizations reflect the broad science themes astronomers will address with Webb. Among them: How did the earliest galaxies interact and evolve to create the present-day universe? How do stars and planets form?

"When we look at the largest scales, we see galaxies packed into clusters and clusters of galaxies packed into superclusters, but we know the universe didn't start out this way," Gardner said. Studies of the cosmic microwave background -- the remnants of light emitted when the universe was just 380,000 years old -- show that the clumpy cosmic structure we see developed much later on. Yet the farthest galaxies studied are already more than 500 million years old.

"Webb will show us what happened in between," Gardner added.

Cox and her AVL team visualized this epoch of cosmic construction from a simulation developed by Renyue Cen and Jeremiah Ostriker at Princeton University in New Jersey. It opens when the universe was 20 million years old and continues to the present-day, when the universe is 13.7 billion years old.

AVL team members Robert Patterson, Stuart Levy, Matthew Hall, Alex Betts and A. J. Christensen visualized how stars, gas, dark matter and colliding galaxies created clusters and superclusters of galaxies. Driven by the gravitational effect of dark matter, these structures connect into enormous crisscrossing filaments that extend over vast distances, forming what astronomers call the "cosmic web."

"We worked with nine scientists at five universities to visualize terabytes of computed data in order to take the viewer on a visual tour from the cosmic web, to smaller scales of colliding galaxies, to deep inside a turbulent nebula where stars and disks form solar systems like our own," Cox said. "These visuals represent current theories that scientists will soon re-examine through the eyes of Webb."

Closer to home, Webb will peer more deeply than ever before into the dense, cold, dusty clouds where stars and planets are born. Using data from models created by Aaron Boley at the University of Florida in Gainesville and Alexei Kritsuk and Michael Norman at the University of California, San Diego, the AVL team visualized the evolution of protoplanetary disks over tens of thousands of years.

Dense clumps develop far out in a disk's fringes, and if these clumps survive they may become gas giant planets or substellar objects called brown dwarfs. The precise outcome depends on the detailed makeup of the disk. "Dr. Boley was interested in what happened in the disk and did not include the central star," Cox said, "so to produce a realistic view we worked with him to add a young star."

This is astrophysics with a pinch of Hollywood sensibility, work at the crossroads of science and art. "The theoretical digital studies that form the basis of our work are so advanced that cinematic visualization is the most effective way to share them with the public," Cox said. "It's the art of visualizing science."

"What AVL has done for the Webb project is truly amazing and inspiring," Gardner noted. "It really whets our appetites for the science we'll be doing when the telescope begins work a few years from now."

For more information visit http://www.nasa.gov/topics/technology/features/supercomputer-preview.html

Sunday, November 7, 2010

NASA EPOXI Flyby Reveals New Insights Into Comet Features


NASA's EPOXI mission spacecraft successfully flew past comet Hartley 2 at 7 a.m. PDT (10 a.m. EDT) Thursday, Nov. 4. Scientists say initial images from the flyby provide new information about the comet's volume and material spewing from its surface.

"Early observations of the comet show that, for the first time, we may be able to connect activity to individual features on the nucleus," said EPOXI Principal Investigator Michael A'Hearn of the University of Maryland, College Park. "We certainly have our hands full. The images are full of great cometary data, and that's what we hoped for."

EPOXI is an extended mission that uses the already in-flight Deep Impact spacecraft. Its encounter phase with Hartley 2 began at 1 p.m. PDT (4 p.m. EDT) on Nov. 3, when the spacecraft began to point its two imagers at the comet's nucleus. Imaging of the nucleus began one hour later.

"The spacecraft has provided the most extensive observations of a comet in history," said Ed Weiler, associate administrator for NASA's Science Mission Directorate at the agency's headquarters in Washington. "Scientists and engineers have successfully squeezed world-class science from a re-purposed spacecraft at a fraction of the cost to taxpayers of a new science project."

Images from the EPOXI mission reveal comet Hartley 2 to have 100 times less volume than comet Tempel 1, the first target of Deep Impact. More revelations about Hartley 2 are expected as analysis continues.

Initial estimates indicate the spacecraft was about 700 kilometers (435 miles) from the comet at the closest-approach point. That's almost the exact distance that was calculated by engineers in advance of the flyby.

"It is a testament to our team's skill that we nailed the flyby distance to a comet that likes to move around the sky so much," said Tim Larson, EPOXI project manager at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "While it's great to see the images coming down, there is still work to be done. We have another three weeks of imaging during our outbound journey."

The name EPOXI is a combination of the names for the two extended mission components: the Extrasolar Planet Observations and Characterization (EPOCh), and the flyby of comet Hartley 2, called the Deep Impact Extended Investigation (DIXI). The spacecraft has retained the name "Deep Impact." In 2005, Deep Impact successfully released an impactor into the path of comet Tempel 1.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, manages the EPOXI mission for NASA's Science Mission Directorate. The spacecraft was built for NASA by Ball Aerospace & Technologies Corp., in Boulder, Colo.

For more information visit http://www.nasa.gov/mission_pages/epoxi/epoxi20101104b.html

Wednesday, November 3, 2010

NASA Mission in Final Day Before Comet Meetup

Mission controllers at NASA's Jet Propulsion Laboratory in Pasadena, Calif., have relayed final instructions to their comet-bound spacecraft today, Nov. 3. The new programming will guide NASA's EPOXI mission through its close approach with comet Hartley 2, scheduled for tomorrow, Nov. 4, at about 7 a.m. PDT (10 a.m. EDT).

"The last 1 million kilometers are always the hardest," said Tim Larson, EPOXI project manager from JPL. "But we've prepared thoroughly for this day and are confident that come tomorrow morning, we'll be getting the kind of data and imagery that will keep our scientists busy for months to come."

Today at 7 a.m. PDT (10 a.m. EDT), NASA's EPOXI mission was about 1,064,900 kilometers (661,700 miles) from Hartley 2 and closing at a rate of 12.3 kilometers (7.6 miles) per second. Tomorrow at the same time, the spacecraft will be at its closest approach distance to the comet -- approximately 700 kilometers (435 miles) away from its nucleus. All the while, the spacecraft's two imagers and one infrared instrument will be acquiring data.

"We are really looking forward to this because the comet has shown so many surprises, both in the data from EPOXI and the data from our many collaborators, over the last several months," said EPOXI principal investigator Mike A'Hearn from the University of Maryland, College Park."

When the EPOXI mission spacecraft is 18 hours and 798 thousand kilometers (496 thousand miles) away, it will lock its instruments on the comet and begin its encounter phase data collection. As the distances between man-made machine and mysterious space dirtball closes, the frequency of image-taking will increase, reaching a crescendo in the minutes surrounding approach. All data collected during encounter phase will be loaded into spacecraft memory for later playback.

If all goes as planned, about 50 minutes before closest approach, the spacecraft's onboard autopilot - AutoNav Mode - is expected to go active. When in AutoNav Mode, the spacecraft receives attitude (pointing) instructions from its computer to help keep the comet's nucleus centered in spacecraft's imagers.

"We're using AutoNav Mode because our mission control is 23 million miles away from the spacecraft at time of encounter," said Larson. "Any command we would send to the spacecraft would take 75 seconds to get there. Not the kind of thing you want to do when you're talking about hurtling past a 2.2 kilometer-wide object [1.36 miles] at 27,500 miles per hour [about 44,256 kilometers per hour]."

AutoNav Mode works by having the spacecraft's Medium-Resolution Imager look for the brightest light source in the sky (excluding the sun). It then assumes that the bright light source must be the comet's nucleus and adjusts the spacecraft's attitude accordingly to keep its imagers centered.

"This spacecraft's AutoNav worked great during its prime mission in 2005 at comet Tempel 1," said Larson. "While that comet's shape provided one central light source, new data from Arecibo indicate that comet Hartley 2 is more elongated and could have two unique bright spots on the ends. If that is the case, we expect Auto Nav to make a decision on which of the two is brightest and focus on that spot."

The EPOXI team expects to begin receiving imagery from the spacecraft starting about 30 minutes after closest approach. The first images received will be those that were taken when the spacecraft was 18 hours out from its target. They will depict the comet nucleus as little more than a point of light, with the fuzzy coma surrounding it. A few of the close-approach images should be received on the ground one hour after the event occurs.

"Those early images may not be the 'money shot,' but we on the science team will prize them just as well, as they will help us further understand the nature of comets," said A'Hearn. "And when we first see those images surrounding closest approach, we are looking forward to yet another type of nucleus compared to any we have seen up close thus far."

EPOXI is an extended mission that uses the already "in-flight" Deep Impact spacecraft to explore distinct celestial targets of opportunity. The name EPOXI itself is a combination of the names for the two extended mission components: the extrasolar planet observations, called Extrasolar Planet Observations and Characterization (EPOCh), and the flyby of comet Hartley 2, called the Deep Impact Extended Investigation (DIXI). The spacecraft has retained the name "Deep Impact."

NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology, manages the EPOXI mission for NASA's Science Mission Directorate, Washington. The University of Maryland, College Park, is home to the mission's principal investigator, Michael A'Hearn. Drake Deming of NASA's Goddard Space Flight Center, Greenbelt, Md., is the science lead for the mission's extrasolar planet observations. The spacecraft was built for NASA by Ball Aerospace & Technologies Corp., Boulder, Colo.

For more information visit http://www.jpl.nasa.gov/news/news.cfm?release=2010-370

Tuesday, November 2, 2010

The Man Behind Comet Hartley 2

Over the last 40 years, Malcolm Hartley has done just about every possible job for Siding Spring Observatory's UK Schmidt telescope in New South Wales, Australia. The British-born, Scottish-educated Hartley has logged time as the 1.2 meter (3.9 foot) telescope's observer, processor, copier, hypersensitization expert, and quality controller.

On the afternoon of March 16, 1986, Hartley's job was that last one - quality control. In that role, he was the first to view each 36-by-36 centimeter (14-by-14 inch) photographic glass plate after it had been exposed to the night sky. Checking for imperfections on one of the previous evening's 60-minute illuminations, Hartley came upon something that wasn't supposed to be there.

"Back then, the observations came in as negatives -- stars and other objects in the sky appeared black on a clear background," said Hartley. "I noticed a dark haze around a trail. Trails indicate something that is traveling fast through the sky, but asteroids don't have a haze. So I thought it might be a comet."

Hartley double-checked his sighting a couple of nights later, then submitted his findings to the Minor Planet Center in Cambridge, Mass. A couple of days after that, the center issued a brief circular informing the astronomical world of the discovery of comet Hartley 2.

"I was very happy for a couple of days," said Hartley."Every scientist wants to discover something and it's a fantastic feeling. There was even a mention in the local paper, the Coonabarabran Times."

On the world's stage, having a comet named after you is certainly unique. But not so much in the small town of Coonabarabran -- which they say comes from the local Aboriginal word for 'inquisitive person.' It is the closest town to the Warrumbungle Range and Siding Spring Mountain and the Anglo-Australian Observatory.

"There are several other colleagues at Siding Springs who have discovered comets," Hartley said. "Robert McNaught has discovered over 50, and I don't think he's ever been mentioned in the Times. It's a rural farming community, and while there are amateur astronomers in the area, finding comets is not really a big deal."

Hartley went on to discover or co-discover 10 comets with the UK Schmidt telescope, and with each, he would feel an initial rush of excitement. But in 2002, the Anglo-Australian Observatory retrofitted its Schmidt to perform multi-object spectroscopy, essentially halting all astrophotography with the telescope and ending any future possibility for comet discovery. Hartley, who never was directly tasked with finding comets, continued to work the telescope's galaxy surveys. Comets, it seemed, had become little more than a historical footnote in his career. That is, until he got a call from a science magazine.

"At the beginning of last year, a reporter emailed and said that the EPOXI mission changed its target and now it was going to go to Hartley 2," said Hartley. "I didn't even know Hartley 2 was one of the two comets under consideration."

Hartley 2 was definitely on NASA's very short list of potential comet targets. The only problem with Hartley 2 was it would take more than two years of extra deep-space cruising to get there. So the only other candidate on the short list, the similar-sized comet Boethin, was selected. That is, until it disappeared. Scientists theorize that comet Boethin had broken into non-traceable fragments. This situation left NASA's short list as a list of one - comet Hartley 2.

So Malcolm Hartley did what anybody would do who has a namesake comet that was just selected as a target for a NASA comet flyby, after the previous selection had disappeared. He thanked the reporter, logged off his computer and wondered what "his comet" would look like. Whatever that was going to be, Hartley was sure he would find out from the comfort of his living room. Then NASA called.

"I've never been involved with a space mission," said Hartley. "I had never visited JPL or any NASA facility for that matter. So this is all new to me. I am very grateful you have asked me to come and witness this. It is an experience very few people have had before."

Exactly once before - of all the approximately 3,800 known comets, four have been imaged closeup by spacecraft. And of those four, only Swiss astronomer Paul Wild (pronounced "Vilt") was alive to see his comet visited. And while Wild witnessed the launch of NASA 's Stardust spacecraft from Cape Canaveral, Fla., in 1999, he watched the close-up images of his comet from the comfort of his living room in 2003. (Wild passed away in 2008). Hartley will see his comet from JPL's mission control room.

"When I discovered the comet in 1986, I never envisaged that I would come to the location where the mission was run, to see it up-close and personal," said Hartley, who was a boy when JPL was starting up.

Not surprisingly, the 63-year-old astrophotographer also has some thoughts on the mission to his comet.

"You went to Tempel 1, but then you reconfigured the spacecraft for the extended mission," said Hartley. "That's pretty clever stuff that you've done. That's the kind of science that's really interesting. To be able to do something extra on top of the successful mission you mounted at Tempel 1, it's really special."

EPOXI is an extended mission that utilizes the already "in-flight" Deep Impact spacecraft to explore distinct celestial targets of opportunity. The term EPOXI is a combination of the names for the two extended mission components: the Extrasolar Planet Observations and Characterization (EPOCh), and the Hartley 2 flyby, called the Deep Impact eXtended Investigation (DIXI).

For more information visit http://www.nasa.gov/mission_pages/epoxi/hartley20101102.html

Monday, November 1, 2010

Major Surgery Complete for Deep Space Network Antenna

The seven-month upgrade to the historic "Mars antenna" at NASA's Deep Space Network site in Goldstone, Calif. has been completed. After a month of intensive testing, similar to the rehabilitation stage after surgery, the antenna is now ready to help maintain communication with spacecraft during the next decade of space exploration.

The month of October was used as a testing period to make sure the antenna was in working order and fully functional, as scheduled, for Nov. 1. A team of workers completed an intense series of tasks to reach its first milestone – upgrading the 70-meter-wide (230-foot-wide) antenna in time to communicate with the EPOXI mission spacecraft during its planned flyby of comet Hartley 2 on Nov. 4.

The first official demonstration space track was on Sept. 28, when the antenna communicated with NASA's EPOXI mission spacecraft.

"We've been testing the antenna since Sept. 28, and we've had no problems in tracking the spacecraft," said Peter Hames of NASA's Jet Propulsion Laboratory, Pasadena, Calif., who is responsible for maintaining the network's antennas. "We are ready to resume service as scheduled." JPL manages the Deep Space Network for NASA.

During the upgrade process, workers raised a portion of the antenna that weighs 3.2 million kilograms (7 million pounds) up from the base by 5 millimeters (0.2 inches) while they performed a precise, delicate repair. They replaced a portion of the hydrostatic bearing (enabling the antenna to rotate horizontally) and the four elevation bearings (enabling the antenna to track up and down from the horizon).

Unlike the sterile confines of an operating room, this surgery took place in the middle of California's Mojave Desert, a hot oasis baked by the unforgiving desert heat. The team members were able to cheat the heat by completing a number of the 375 tasks during early morning and night shifts. The tasks required the team to analyze, load, lift, install, test, analyze again and inspect.

The Deep Space Network consists of three deep-space communication facilities positioned approximately 120 degrees of longitude apart. In addition to the Mojave Desert location at Goldstone, the other locations are outside of Madrid, Spain, and Canberra, Australia. Each 70-meter (230-foot) antenna is capable of tracking a spacecraft traveling more than 16 billion kilometers (10 billion miles) from Earth. The antennas are strategically situated at each location in semi-mountainous basins to reduce radio frequency interference. This careful placement helps make the Deep Space Network the largest and most sensitive science telecommunications system in the world.

In March 1966, the antenna, officially known as Deep Space Station 14, earned its nickname as the Mars antenna by receiving the first signal from NASA's Mariner 4 mission to Mars. The historic dish is now responsible for tracking an entire fleet of missions, including the rovers Spirit and Opportunity currently on the surface of Mars, the Cassini orbiter at Saturn, the twin Voyager spacecraft in the outer reaches of our solar system, and the Spitzer Space Telescope, which observes stars, galaxies and other celestial objects.

"We are nearing the completion of a very challenging engineering effort that will extend the life of one of the DSN's workhorses, making it more available and reliable in returning critical science data through at least 2025," said Wayne Sible, the network's deputy project manager at JPL.

The antenna upgrade was a collaborative effort between JPL, Diani Building Corp., Santa Maria, Calif., and ITT Corp., White Plains, N.Y. Their shared goal was to emerge from the "operating room" with a healthy patient.

"The 70-meter antenna gets under your skin, everyone involved in this project was so passionate about it, from the grout workers to the machine shops to the guys on the antenna, everybody was giving it their absolute all," said Hames.

JPL, a division of the California Institute of Technology in Pasadena, manages the Deep Space Network for NASA Headquarters, Washington.

For more information visit http://www.nasa.gov/topics/technology/features/dsn20101101.html