Monday, November 30, 2009

COBE Satellite Marks 20th Anniversary

This COBE informational video was produced more than 20 years ago, before the satellite embarked on its mission to study the cosmic microwave backgroundNASA's Cosmic Background Explorer (COBE) satellite rocketed into Earth orbit on Nov. 18, 1989, and quickly revolutionized our understanding of the early cosmos. Developed and built at Goddard Space Flight Center in Greenbelt, Md., COBE precisely measured and mapped the oldest light in the universe -- the cosmic microwave background.

COBE showed that the radiation's spectrum agrees exactly with predictions based on the Big Bang theory. And COBE's map of slight hot and cold spots within this background let scientists glimpse the roots of cosmic structure we see around us today. In essence, COBE produced the first "baby picture" of the universe.

For these results, COBE scientists John Mather, at Goddard, and George Smoot, at the University of California, Berkeley, shared the 2006 Nobel Prize in physics. The mission ushered cosmologists into a new era of precision measurements, paving the way for deeper exploration of the microwave background by NASA's ongoing WMAP mission and the European Space Agency's new Planck satellite.

All sky map from COBE
The cosmic microwave background radiation is a remnant of the Big Bang. These minute temperature variations (depicted here as varying shades of blue and purple) are linked to slight density variations in the early universe. These variations are believed to have given rise to the structures that populate the universe today: clusters of galaxies, as well as vast, empty regions. This image, representing data collected between 1990 and 1992, received much publicity at the time. It was later superseded by a more accurate four-year COBE map.

Related Links:

› View COBE sky map images
› Read about WMAP, successor mission to COBE
› View interactive presentation from Dr. Mather
› NASA Scientist Shares Nobel Prize for Physics -- 2006

Sunday, November 29, 2009

NASA and Microsoft Allow Earthlings to Become Martians


Be A Martian Screenshot
A new Web site allows you to participate as citizen scientists to improve Martian maps, take part in research tasks, and assist Mars science teams studying data about the Red Planet. › Explore Now →

NASA and Microsoft Corp. of Redmond, Wash., have collaborated to create a Web site where Internet users can have fun while advancing their knowledge of Mars.

Drawing on observations from NASA’s Mars missions, the "Be a Martian" Web site will enable the public to participate as citizen scientists to improve Martian maps, take part in research tasks, and assist Mars science teams studying data about the Red Planet.

"We're at a point in history where everyone can be an explorer," said Doug McCuistion, director of the Mars Exploration Program at NASA Headquarters in Washington. "With so much data coming back from Mars missions that are accessible by all, exploring Mars has become a shared human endeavor. People worldwide can expand the specialized efforts of a few hundred Mars mission team members and make authentic contributions of their own."

Participants will be able to explore details of the solar system's grandest canyon, which resides on Mars. Users can call up images in the Valles Marineris canyon before moving on to chart the entire Red Planet. The collaboration of thousands of participants could assist scientists in producing far better maps, enabling smoother zoom-in views and easier interpretation of Martian surface changes.

By counting craters, the public also may help scientists determine the relative ages of small regions on Mars. In the past, counting Martian craters has posed a challenge because of the vast numbers involved. By contributing, Web site users will win game points assigned to a robotic animal avatar they select.

With a common goal of inspiring digital-age workforce development and life-long learning in science, technology, engineering and mathematics, NASA and Microsoft unveiled the Web site at the Microsoft Professional Developers Conference in Los Angeles this week. The site also beckons software developers to win prizes for creating tools that provide access to and analysis of hundreds of thousands of Mars images for online, classroom and Mars mission team use.

"Industry leaders like NASA and Microsoft have a social responsibility as well as a vested interest in advancing science and technology education," said Walid Abu-Hadba, corporate vice president of the Developer and Platform Evangelism Group at Microsoft. "We are excited to be working with NASA to provide new opportunities to engage with Mars mission data, and to help spark interest and excitement among the next generation of scientists and technologists."

To encourage more public participation, the site also provides a virtual town hall forum where users can expand their knowledge by proposing Mars questions and voting on which are the most interesting to the community. Online talks by Mars experts will address some of the submitted questions. Other features include interactive tools for viewing Martian regions and movies about people who study Mars in diverse ways.

"Mars exploration inspires people of all ages, and we are especially eager to encourage young people to explore Mars for themselves," said Charles Elachi, director of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We are delighted to be involved in providing the creative opportunity for future explorers to contribute to our understanding of Mars."

"The beauty of this type of experience is that it not only teaches people about Mars and the work NASA is doing there, but it also engages large groups of people to help solve real challenges that computers cannot solve by themselves," said Marc Mercuri, director of business innovation in the Developer and Platform Evangelism Group at Microsoft.

The Mars Exploration Program is managed by JPL for NASA's Science Mission Directorate in Washington.

To enroll as a virtual Martian citizen and start exploring, visit . For more exploration on NASA's Mars exploration program, visit .

Friday, November 27, 2009

NASA EDGE Nominated for Best Video Podcast

NASA EDGE Nominated for ‘Best Video Podcast’ in the 5th Annual Podcast Awards! ›› Vote Now for NASA EDGE!
NASA EDGE continues their unprecedented, unscripted journey through the world of video podcasting with their very first award nomination. This is no small accomplishment considering that only two and half years ago, they weren’t sure that they would find an audience.

NASA EDGEWell, they have. Almost three years and 3.2 million downloads later, NASA EDGE is now recognized in the company of such internet greats and fellow nominees as “Buzz out Loud,” “Diggnation” and “Filmriot” just to name a few.

In fact, the 5th Annual Podcast Awards, managed by Podcast Connect Inc., mentioned on their Web site that this year’s competition received more than 321,000 nominations for over 3,500 different shows.

Be sure to vote for NASA EDGE

You can vote once a day from November 13 to November 30, 2009 by visiting NASA EDGE is listed in the “Best Video Podcast” category with nine other video podcasts.

If you’re already a fan of NASA EDGE, please vote for them. If you haven’t seen or heard of NASA EDGE, visit their home page at and download any or all of their 46 video podcasts. You will not be disappointed.

What is NASA EDGE?

NASA EDGE is different. Unscripted and unpredictable, NASA EDGE takes a unique look in and around the greatest space program on the planet. They have hosted the Great Moonbuggy Race, examined NASA spinoff technology at the X Games, followed the Desert-RATS with an unconventional set of duct tape boots, coined the term Magnetospherence and even made an appearance on ESPN’s nationally syndicated "Mike & Mike in the Morning" show.

Check out their latest Vodcast, which added a new wrinkle. In October they covered NASA’s historic Ares I-X Flight Demonstration live on the Web. That show featured the entire broadcast team and an attempt at defining and redefining 'triboelectrification.'

NASA EDGE Co-host, Blair AllenOf course, NASA EDGE isn’t just a video podcast. If you have questions, comments or thoughts about NASA or NASA EDGE, you can friend them on facebook and ask questions, chat or check out some exclusive facebook videos.

Or if you just want to keep up with their latest shows or activities you can follow them on twitter (@NASA_EDGE).

If all goes well, you’ll hear from them the second they win their very first award!

› Don't forget to vote at!

› Visit the NASA Edge Home Page

Wednesday, November 25, 2009

NASA's LCROSS Impacts Confirm Water in Lunar Crater

Preliminary data from NASA's Lunar Crater Observation and Sensing Satellite, or LCROSS, indicates the mission successfully uncovered water in a permanently shadowed lunar crater. The discovery opens a new chapter in our understanding of the moon.

The LCROSS spacecraft and a companion rocket stage made twin impacts in the Cabeus crater Oct. 9 that created a plume of material from the bottom of a crater that has not seen sunlight in billions of years. The plume traveled at a high angle beyond the rim of Cabeus and into sunlight, while an additional curtain of debris was ejected more laterally.

"We're unlocking the mysteries of our nearest neighbor and, by extension, the solar system," said Michael Wargo, chief lunar scientist at NASA Headquarters in Washington. "The moon harbors many secrets, and LCROSS has added a new layer to our understanding."

Scientists long have speculated about the source of significant quantities of hydrogen that have been observed at the lunar poles. The LCROSS findings are shedding new light on the question with the discovery of water, which could be more widespread and in greater quantity than previously suspected. If the water that was formed or deposited is billions of years old, these polar cold traps could hold a key to the history and evolution of the solar system, much as an ice core sample taken on Earth reveals ancient data. In addition, water and other compounds represent potential resources that could sustain future lunar exploration.

Since the impacts, the LCROSS science team has been analyzing the huge amount of data the spacecraft collected. The team concentrated on data from the satellite's spectrometers, which provide the most definitive information about the presence of water. A spectrometer helps identify the composition of materials by examining light they emit or absorb.

"We are ecstatic," said Anthony Colaprete, LCROSS project scientist and principal investigator at NASA's Ames Research Center in Moffett Field, Calif. "Multiple lines of evidence show water was present in both the high angle vapor plume and the ejecta curtain created by the LCROSS Centaur impact. The concentration and distribution of water and other substances requires further analysis, but it is safe to say Cabeus holds water."

The team took the known near-infrared spectral signatures of water and other materials and compared them to the impact spectra the LCROSS near infrared spectrometer collected.

"We were able to match the spectra from LCROSS data only when we inserted the spectra for water," Colaprete said. "No other reasonable combination of other compounds that we tried matched the observations. The possibility of contamination from the Centaur also was ruled out."

Additional confirmation came from an emission in the ultraviolet spectrum that was attributed to hydroxyl, one product from the break-up of water by sunlight. When atoms and molecules are excited, they release energy at specific wavelengths that can be detected by the spectrometers. A similar process is used in neon signs. When electrified, a specific gas will produce a distinct color. Just after impact, the LCROSS ultraviolet visible spectrometer detected hydroxyl signatures that are consistent with a water vapor cloud in sunlight.

Data from the other LCROSS instruments are being analyzed for additional clues about the state and distribution of the material at the impact site. The LCROSS science team and colleagues are poring over the data to understand the entire impact event, from flash to crater. The goal is to understand the distribution of all materials within the soil at the impact site.

"The full understanding of the LCROSS data may take some time. The data is that rich," Colaprete said. "Along with the water in Cabeus, there are hints of other intriguing substances. The permanently shadowed regions of the moon are truly cold traps, collecting and preserving material over billions of years."

LCROSS was launched June 18 from NASA's Kennedy Space Center in Florida as a companion mission to the Lunar Reconnaissance Orbiter, or LRO. Moving at a speed of more than 1.5 miles per second, the spent upper stage of its launch vehicle hit the lunar surface shortly after 4:31 a.m. PDT Oct. 9, creating an impact that instruments aboard LCROSS observed for approximately four minutes. LCROSS then impacted the surface at approximately 4:36 a.m.

LRO observed the impact and continues to pass over the site to give the LCROSS team additional insight into the mechanics of the impact and its resulting craters. The LCROSS science team is working closely with scientists from LRO and other observatories that viewed the impact to analyze and understand the full scope of the LCROSS data.

For information about LCROSS, visit:

Monday, November 23, 2009

Distal Rampart of Crater in Chryse Planitia

Distal rampart of crater in Chryse Planitia on Mars
The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter took this image of a distal rampart of a crater in Chryse Planitia on Mars.

Impact craters on Mars are kind of neat. Many of them look very different than impact craters seen on Earth's moon or Mercury. Fresh lunar and Mercurian craters have ejecta blankets that look a bit rough near the crater rims; around larger craters, long rays or chains of secondary craters radiate away from the crater rims. Some Martian craters are similar to these craters, but Mars also has a high proportion of craters with forms not found on the moon or Mercury: rampart craters.

Rampart craters, also called fluidized-ejecta craters, have ejecta blankets that appear lobate, or rounded, in plan view, and end in low ridges or ramparts. An example of a such a rampart is the ridge in this image from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter. Here you see the rampart at the edge of an ejecta blanket that comes from an approximately 16-kilometer-diameter (10-mile-diameter) crater, about 16 kilometers (10 miles) to the east.

For years there has been a debate about whether these lobes and ramparts were formed by ejecta interacting with the thin Martian atmosphere, or whether they formed because volatiles (such as water or ice) in the subsurface were incorporated into the ejecta material excavated by the impact. The common consensus is now in favor of the volatile hypothesis. Because of this, rampart craters can be used to indicate the past presence of water or ice in the Martian crust.

This image covers a swath of ground about 6 kilometers (4 miles) wide, centered at 17.2 degrees north latitude, 311.6 degrees east longitude. It is one product from HiRISE observation ESP_14417_1975, made on Aug. 23, 2009. Other image products from this observation are available at

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter for the NASA Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft. The University of Arizona, Tucson, operates the HiRISE camera, which was built by Ball Aerospace & Technologies Corp., Boulder, Colo.

Students Send Microbe Experiment on Space Shuttle Atlantis

An experiment by college students that will study how microbes grow in microgravity is heading to orbit aboard space shuttle Atlantis.

Undergraduate and graduate students at Texas Southern University in Houston developed the experiment that will fly as part of the STS-129 mission. The mission is scheduled to launch at 2:28 p.m. EST on Nov. 16 from NASA's Kennedy Space Center in Florida.

"I'm thrilled that giving students the chance to design and research an experiment to fly in space is one of the tools we have at NASA to engage them in science, technology, engineering and mathematics," NASA Deputy Administrator Lori B. Garver said." These young people are our future, and providing an opportunity to inspire them is a major part of our mission at NASA."

NASA's Office of Education selected Texas Southern University as a 2008 University Research Center. Texas Southern established a Center for Bio-nanotechnology and Environmental Research. Students at the center developed the Microbial-1 experiment to evaluate the morphological and molecular changes in E. coli and B. subtilis bacteria.

"The University Research Center Project is designed to enhance the research infrastructure and capacity at minority institutions," said Katrina Emery, NASA's University Research Center project manager at the agency's Dryden Flight Research Center in Edwards, Calif. "By engaging in participatory learning opportunities like this experiment, students can see themselves as researchers, now and in the future."

This space station shuttle flight experiment is a proof-of-concept model for the URC project to give students hands-on experience. The experiment provides the university students the opportunity to design, monitor and execute the study in laboratories, as well as near real-time on the space shuttle. Each component of the experiment is designed for easy reproduction in the classroom, providing a valuable experience to students.

"This is an amazing opportunity for our students, and it reflects the growing quality of our research programs at Texas Southern," said John M. Rudley, president of Texas Southern University. "We are excited our students have the opportunity to participate in such relevant research. We are also pleased that with our partnerships with area school districts, we are able to take these projects beyond the university to the school classrooms to encourage more students to study science, math, and technology."

The unique experimental data will be used to develop grade-appropriate microbiology modules for students in kindergarten through twelfth grade. Data downloaded from NASA's Payload Operations and Control Center will be available on the research center's Web site. In addition, educators will receive a teacher's guidebook featuring background information, lesson plans and student activities for conducting this project in their classrooms. BioServe Space Technologies at the University of Colorado is providing management support and hardware for the experiment.

Texas Southern University is one of 13 universities to receive grant funding from NASA's University Research Center project. The project is designed to enhance the research capabilities of minority-serving institutions and increase the production of underrepresented and underserved students majoring in science, technology, engineering and mathematics disciplines.

For information about NASA education programs, visit:

For information about Texas Southern University's Center for Bio-nanotechnology and Environmental Research, visit:

NASA's Digital Learning Network will host a launch day webcast Nov. 16 beginning at 1:28 p.m. EST and culminating with liftoff. The webcast will feature a discussion about the Microbial-1 experiment. Watch online at:

For information about the STS-129 mission to the International Space Station, visit:

Thursday, November 19, 2009

NASA to Begin Attempts to Free Sand-Trapped Mars Rover

Computer reconstruction of Spirit's predicament
NASA will begin transmitting commands to its Mars exploration rover Spirit on Monday as part of an escape plan to free the venerable robot from its Martian sand trap.

Spirit has been lodged at a site scientists call "Troy" since April 23. Researchers expect the extraction process to be long and the outcome uncertain based on tests here on Earth this spring that simulated conditions at the Martian site.

"This is going to be a lengthy process, and there's a high probability attempts to free Spirit will not be successful" said Doug McCuistion, director of the Mars Exploration Program at NASA Headquarters in Washington. "After the first few weeks of attempts, we're not likely to know whether Spirit will be able to free itself."

Spirit has six wheels for roving the Red Planet. The first commands will tell the rover to rotate its five working wheels forward approximately six turns. Engineers anticipate severe wheel slippage, with barely perceptible forward progress in this initial attempt. Since 2006, Spirit's right-front wheel has been inoperable, possibly because of wear and tear on a motor as a result of the rover's longevity.

Spirit will return data the next day from its first drive attempt. The results will be assessed before engineers develop and send commands for a second attempt. Using results from previous commands, engineers plan to continue escape efforts until early 2010.

"Mobility on Mars is challenging, and whatever the outcome, lessons from the work to free Spirit will enhance our knowledge about how to analyze Martian terrain and drive future Mars rovers," McCuisition said. "Spirit has provided outstanding scientific discoveries and shown us astounding vistas during its long life on Mars, which is more than 22 times longer than its designed life."

In the spring, Spirit was driving backward and dragging the inoperable right front wheel. While driving in April, the rover's other wheels broke through a crust on the surface that was covering a bright-toned, slippery sand underneath. After a few drive attempts to get Spirit out in the subsequent days, it began sinking deeper in the sand trap. Driving was suspended to allow time for tests and reviews of possible escape strategies.

"The investigations of the rover embedding and our preparations to resume driving have been extensive and thorough," said John Callas, project manager for Spirit and Opportunity at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We've used two different test rovers here on Earth in conditions designed to simulate as best as possible Spirit's predicament. However, Earth-based tests cannot exactly replicate the conditions at Troy."

Data show Spirit is straddling the edge of a 26-foot-wide crater that had been filled long ago with sulfate-bearing sands produced in a hot water or steam environment. The deposits in the crater formed distinct layers with different compositions and tints, and they are capped by a crusty soil. It is that soil that Spirit's wheels broke through. The buried crater lies mainly to Spirit's left. Engineers have plotted an escape route from Troy that heads up a mild slope away from the crater.

"We'll start by steering the wheels straight and driving, though we may have to steer the wheels to the right to counter any downhill slip to the left," said Ashley Stroupe, a JPL rover driver and Spirit extraction testing coordinator. "Straight-ahead driving is intended to get the rover's center of gravity past a rock that lies underneath Spirit. Gaining horizontal distance without losing too much vertical clearance will be a key to success. The right front wheel's inability to rotate greatly increases the challenge."

Spirit has been examining its Martian surroundings with tools on its robotic arm and its camera mast. The rover's work at Troy has augmented earlier discoveries it made indicating ancient Mars had hot springs or steam vents, possible habitats for life. If escape attempts fail, the rover's stationary location may result in new science findings.

"The soft materials churned up by Spirit's wheels have the highest sulfur content measured on Mars,” said Ray Arvidson a scientist at Washington University in St. Louis and deputy principal investigator for the science payloads on Spirit and Opportunity. “We're taking advantage of its fixed location to conduct detailed measurements of these interesting materials."

Spirit and its twin rover landed on Mars in January 2004. They have explored Mars for five years, far surpassing their original 90-day mission. Opportunity currently is driving toward a large crater called Endeavor.

NASA's JPL manages the rovers for NASA's Science Mission Directorate in Washington.

For updates about Spirit's progress, visit:

The 2009 Leonid Meteor Shower

This year's Leonid meteor shower peaks on Tuesday, Nov. 17th. If forecasters are correct, the shower should produce a mild but pretty sprinkling of meteors over North America followed by a more intense outburst over Asia. The phase of the Moon will be new, setting the stage for what could be one of the best Leonid showers in years.

see caption"We're predicting 20 to 30 meteors per hour over the Americas, and as many as 200 to 300 per hour over Asia," says Bill Cooke of NASA's Meteoroid Environment Office. "Our forecast is in good accord with independent theoretical work by other astronomers."1

Leonids are bits of debris from Comet Tempel-Tuttle. Every 33 years the comet visits the inner solar system and leaves a stream of dusty debris in its wake. Many of these streams have drifted across the November portion of Earth's orbit. Whenever we hit one, meteors come flying out of the constellation Leo.

"We can predict when Earth will cross a debris stream with pretty good accuracy," says Cooke. "The intensity of the display is less certain, though, because we don't know how much debris is in each stream." Caveat observer!

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The first stream crossing on Nov. 17th comes around 0900 UT (4 a.m. EST, 1 a.m. PST). The debris is a diffuse mix of particles from several old streams that should produce a gentle display of two to three dozen meteors per hour over North America. Dark skies are recommended for full effect.

"A remarkable feature of this year's shower is that Leonids will appear to be shooting almost directly out of the planet Mars," notes Cooke.

It's just a coincidence. This year, Mars happens to be passing by the Leonid radiant at the time of the shower. The Red Planet is almost twice as bright as a first magnitude star, so it makes an eye-catching companion for the Leonids: sky map.

see caption

Above: This side of Earth will be facing the Leonid debris stream at the time of the Nov. 17th outburst. Observers in India, China and Indonesia are favored with dark, pre-dawn skies. Image credit: Danielle Moser of the NASA Meteoroid Environment Office.

The next stream crossing straddles the hour 2100-2200 UT, shortly before dawn in Indonesia and China. At that time, Earth will pass through a pair of streams laid down by Comet Tempel-Tuttle in 1466 and 1533 AD. The double crossing could yield as many as 300 Leonids per hour.

"Even if rates are only half that number, it would still be one of the best showers of the year," says Cooke.

The Leonids are famous for storming, most recently in 1999-2002 when deep crossings of Tempel-Tuttle's debris streams produced outbursts of more than 1000 meteors per hour. The Leonids of 2009 won't be like that, but it only takes one bright Leonid streaking past Mars to make the night worthwhile.

Wednesday, November 18, 2009

NASA Briefs Preliminary Plume Findings from Moon Mission

NASA will hold a news conference Friday to talk about early science results from its successful moon impacting mission, the Lunar Crater Observation and Sensing Satellite, or LCROSS. The satellite gained worldwide attention when it plunged into a crater near the moon's south pole on Oct. 9.

The briefing from NASA's Ames Research Center in Moffett Field, Calif., will begin at 9 a.m. PST, on Nov. 13. It will be broadcast live on NASA Television and the agency's Web site. For NASA TV streaming video, downlink and scheduling information, visit:

The panelists are:

- Doug Cooke, associate administrator, Exploration Systems Mission Directorate at NASA Headquarters in Washington
- Michael Wargo, chief lunar scientist for Exploration Systems at NASA Headquarters
- Anthony Colaprete, LCROSS project scientist and principal investigator from Ames
- Greg Delory, senior fellow, Space Sciences Laboratory and Center for Integrative Planetary Sciences at the University of California, Berkeley

To attend or participate by telephone reporters should contact Jonas Dino ( at 650-604-5612 or Rachel Prucey ( at 650-604-0643.

For information about the LCROSS mission, visit:

Tuesday, November 17, 2009

Swift XMM-Newton Satellites Tune Into a Middleweight Black Hole

Swift X-ray observations of galaxy NGC 5408 indicate its ultraluminous X-ray source undergoes periodic changes every 115.5 daysWhile astronomers have studied lightweight and heavyweight black holes for decades, the evidence for black holes with intermediate masses has been much harder to come by. Now, astronomers at NASA's Goddard Space Flight Center in Greenbelt, Md., find that an X-ray source in galaxy NGC 5408 represents one of the best cases for a middleweight black hole to date.

"Intermediate-mass black holes contain between 100 and 10,000 times the sun's mass," explained Tod Strohmayer, an astrophysicist at Goddard. "We observe the heavyweight black holes in the centers of galaxies and the lightweight ones orbiting stars in our own galaxy. But finding the 'tweeners' remains a challenge."

Several nearby galaxies contain brilliant objects known as ultraluminous X-ray sources (ULXs). They appear to emit more energy than any known process powered by stars but less energy than the centers of active galaxies, which are known to contain million-solar-mass black holes.

"ULXs are good candidates for intermediate-mass black holes, and the one in galaxy NGC 5408 is especially interesting," said Richard Mushotzky, an astrophysicist at the University of Maryland, College Park. The galaxy lies 15.8 million light-years away in the constellation Centaurus.

Using the European Space Agency's orbiting XMM-Newton observatory, Strohmayer and Mushotzky studied the source -- known as NGC 5408 X-1 -- in 2006 and 2008.

XMM-Newton detected what the astronomers call "quasi-periodic oscillations," a nearly regular "flickering" caused by the pile-up of hot gas deep within the accretion disk that forms around a massive object. The rate of this flickering was about 100 times slower than that seen from stellar-mass black holes. Yet, in X-rays, NGC 5408 X-1 outshines these systems by about the same factor.

Based on the timing of the oscillations and other characteristics of the emission, Strohmayer and Mushotzky conclude that NGC 5408 X-1 contains between 1,000 and 9,000 solar masses. This study appears in the October 1 issue of The Astrophysical Journal.

This archival image taken by the Hubble Space Telescope shows the location of NGC 5408's unusually luminous X-ray source (circled)"For this mass range, a black hole's event horizon -- the part beyond which we cannot see -- is between 3,800 and 34,000 miles across, or less than half of Earth's diameter to about four times its size," said Strohmayer.

If NGC 5408 X-1 is indeed actively gobbling gas to fuel its prodigious X-ray emission, the material likely flows to the black hole from an orbiting star. This is typical for stellar-mass black holes in our galaxy.

Strohmayer next enlisted the help of NASA's Swift satellite to search for subtle variations of X-rays that would signal the orbit of NGC 5408 X-1's donor star. "Swift uniquely provides both the X-ray imaging sensitivity and the scheduling flexibility to enable a search like this," he added. Beginning in April 2008, Swift began turning its X-Ray Telescope toward NGC 5408 X-1 a couple of times a week as part of an on-going campaign.

Swift detects a slight rise and fall of X-rays every 115.5 days. "If this is indeed the orbital period of a stellar companion," Strohmayer said, "then it's likely a giant or supergiant star between three and five times the sun's mass." This study has been accepted for publication in a future issue of The Astrophysical Journal.

The Swift observations cover only about four orbital cycles, so continued observation is needed to confirm the orbital nature of the X-ray modulation.

"Astronomers have been studying NGC 5408 X-1 for a long time because it is one of the best candidates for an intermediate-mass black hole," adds Philip Kaaret at the University of Iowa, who has studied the object at radio wavelengths but is unaffiliated with either study. "These new results probe what is happening close to the black hole and add strong evidence that it is unusually massive."

Related Links:

> NASA's Swift mission

Monday, November 16, 2009

NASA and Spaceward Foundation Award Prize Money for Successful Wireless Power Demonstration

NASA has awarded $900,000 in prize money to a Seattle company that successfully demonstrated new wireless energy beaming technology which could one day be used to help power a "space elevator."

LaserMotive of Seattle was awarded the money after its performance in the Power Beaming Challenge competition, which was a demonstration of wireless power transmission that enabled a robotic device to climb a vertical cable. The competition was held Nov. 4-6 at NASA's Dryden Flight Research Center in Edwards, Calif. The Spaceward Foundation of Mountain View, Calif., manages the competition for NASA's Centennial Challenges program.

To win a prize, teams had to develop a power transmission system and robotic climber that could reach a height of 3,280 feet. Teams that reached the top share in a total purse of $2 million, based on their vertical speed and payload mass.

LaserMotive's average speed on their best of several successful climbs was 8.7 mph over a four minute period. By exceeding the average speed of 4.5 mph and being the only team to reach the top of the cable, LaserMotive claimed the entire $900,000 prize for that level. Teams had to exceed an average speed of approximately 11 mph to qualify for a share of the remaining prize purse of $1.1 million. That amount will remain available for the next Power Beaming competition.

NASA is interested in power-beaming technology for a variety of purposes including remotely powering rovers and instruments on the moon. On Earth, the technology might supply communities with power following natural disasters. There also are potential applications for power beaming for airships, satellites and space transportation, including the space elevator concept.

LaserMotive was competing with two other teams, the Kansas City Space Pirates and the USST team from South Bend, Ind. Although they did not post prize-winning performances, the other teams kept the contest outcome in doubt up until the final moments.

"I have watched these teams steadily improve their designs since we began the challenge in 2005 and the sophistication of the systems that they demonstrated this week is impressive by any standard." said Ben Shelef of the Spaceward Foundation.

A vertical "racetrack" was created for the competition by suspending a cable from a helicopter flying 4,300 feet overhead. This arrangement, along with the high-power laser systems, provided a unique and unprecedented testing environment.

"The kilometer-high vertical cable system established for this competition was something that had never been done before and is a remarkable accomplishment in itself. The Spaceward Foundation and their partners, along with our hosts at NASA Dryden, deserve a lot of credit for their creativity and determination." said Andrew Petro, Centennial Challenge program manager.

The Power Beaming Challenge is one of six Centennial Challenges managed by NASA's Innovative Partnership Program. NASA's Centennial Challenges program's goals are to drive progress in aerospace technology that is of value to NASA's missions; encourage participation of independent teams, individual inventors, student groups and private companies of all sizes in aerospace research and development; and find innovative solutions to technical challenges through competition and cooperation.

Official results, as well as video and photography, are available at:

For more information on Centennial Challenges, visit:

For more information about NASA and agency programs, visit:

Saturday, November 14, 2009

NASA's GOES Project Offers Real-Time Hurricane Alley Movies

NASA GOES Project now offers real-time HDTV movies of the east- and west-coast hurricane alley regions. This is a short movie of GOES satellite imagery showing Hurricane Bill from August 2009People love to get the big picture of hurricane alleys, and thanks to the GOES Project at NASA's Goddard Space Flight Center in Greenbelt, Md., they can now get real-time satellite animations of the eastern Pacific and Atlantic Oceans.

NASA's Geostationary Operational Environmental Satellite (GOES) Project is offering real-time HDTV movies of the east- and west-coast "hurricane alley" regions. There are two types of movies for both the Eastern Pacific Ocean and the Atlantic Ocean. There are "Coastal" and "Global" movies. The two coastal movies (one for each ocean) show four satellite image frames per hour over the previous two days. The two global movies show two frames per hour over the most recent three days. All four movies are automatically updated every hour.

"The color frames are composed by overlaying the National Oceanic and Atmospheric Administration's (NOAA) GOES cloud images on a true-color background previously derived from NASA's Moderate Imaging Spectroradiometer (MODIS) imager," said GOES Project Scientist Dennis Chesters on the NASA GOES Project at Goddard. MODIS is an instrument that flies aboard NASA's Aqua and Terra satellites to provide color imagery of the Earth's surface. "The GOES infrared images show the convective storms 24 hours a day. During daylight, the GOES visible images reveal the low clouds that provide detail and a sense of the low-level winds," Chesters said.

Hurricanes develop far from land in wide areas of the sub-tropical Atlantic and Pacific oceans, where only satellites can provide up-to-date weather data. NASA's GOES Project has created a method to animate satellite imagery on a true-color map over that large area to watch the early development of hurricanes.

"These new live animations provide panoramic views of each hurricane alley in HDTV wide-screen format," Chesters said. Viewers can see tropical cyclones in the Pacific developing off of the western Mexican or Central American coasts, potentially threatening Mexico or Hawaii. The Atlantic panorama revels the potential hurricanes that threaten the Caribbean islands and the USA's eastern and gulf coasts, and also shows the constant flow of convective storms across the eastern United States.

All of the animations can be found at the NASA GOES Project Web page: There are four links, each labeled "Hurricane Alley HDTV," next to the GOES-EAST and the GOES-WEST images of the USA and the globe. Each link delivers a hurricane alley movie from the area suggested by the image next to the link.

For example, to see what's happening in the always stormy Atlantic, click the link next to the GOES-EAST global image:

Stretch your browser window wide to see the entire panorama.

The "global view" of the Atlantic Ocean is most interesting because it displays several weather regimes simultaneously. It shows the easterly winds in Hurricane Alley, daily thunderstorms over the Antilles, storms across the southeast U.S., the prevailing westerly winds and Atlantic storms at mid-latitudes.

There is a little date/time stamp in the lower left corner of each frame so viewers know which day they're viewing. The date/time is odometer-style: YYMMDDhhmm, an abbreviation for YEAR-MONTH-DAY-hour-minute, and is in Universal Time.

The movies are 1280x720p MPEG4 (H.264) in an Apple Quicktime file, and are about 20 Megabytes each.

Hurricane Alley animations can be found at the NASA GOES Project Web page.

Thursday, November 12, 2009

Poisk Poised for Live NASA TV Space Station Docking

NASA Television will air the docking of the newest Russian module to the International Space Station starting at 9 a.m. CST Nov. 12.

The Mini Research Module-2, known as "Poisk," which means "explore" in Russian, will deliver 1,800 pounds of cargo to the station. Poisk is scheduled to automatically dock to the station's Zvezda Service Module at 9:44 a.m.

The 8-ton module is scheduled to launch at 8:22 a.m. Nov. 10 from the Baikonur Cosmodrome in Kazakhstan. The combination docking port and airlock will ride atop a Soyuz booster rocket. The Soyuz launch will not be broadcast on NASA TV.

The module will be used as an additional docking port for Russian vehicles, as an airlock for Russian-based spacewalks and as a platform for external science experiments. Its first use will be as a docking port during the relocation of a Soyuz crew vehicle in January.

A companion module, the Mini Research Module-1, will be carried to orbit on space shuttle Atlantis' STS-132 mission, targeted to launch in May 2010. That module will be robotically attached to the station's Zarya module.

For more information about the space station, visit:

For more information about how to access NASA Television, visit:

Wednesday, November 11, 2009

NASA Hubble image showcases star birth in M83, the Southern Pinwheel

Hubble Image of M83 galaxy
NASA, ESA, R. O'Connell (University of Virginia), B. Whitmore (Space Telescope Science Institute), M. Dopita (Australian National University), and the Wide Field Camera 3 Science Oversight Committee

The spectacular new camera installed on NASA's Hubble Space Telescope during Servicing Mission 4 in May has delivered the most detailed view of star birth in the graceful, curving arms of the nearby spiral galaxy M83.

Nicknamed the Southern Pinwheel, M83 is undergoing more rapid star formation than our own Milky Way galaxy, especially in its nucleus. The sharp "eye" of the Wide Field Camera 3 (WFC3) has captured hundreds of young star clusters, ancient swarms of globular star clusters, and hundreds of thousands of individual stars, mostly blue supergiants and red supergiants.

The image at right is Hubble's close-up view of the myriad stars near the galaxy's core, the bright whitish region at far right. An image of the entire galaxy, taken by the European Southern Observatory's Wide Field Imager on the ESO/MPG 2.2-meter telescope at La Silla, Chile, is shown at left. The white box outlines Hubble's view.

WFC3's broad wavelength range, from ultraviolet to near-infrared, reveals stars at different stages of evolution, allowing astronomers to dissect the galaxy's star-formation history.

The image reveals in unprecedented detail the current rapid rate of star birth in this famous "grand design" spiral galaxy. The newest generations of stars are forming largely in clusters on the edges of the dark dust lanes, the backbone of the spiral arms. These fledgling stars, only a few million years old, are bursting out of their dusty cocoons and producing bubbles of reddish glowing hydrogen gas.

The excavated regions give a colorful "Swiss cheese" appearance to the spiral arm. Gradually, the young stars' fierce winds (streams of charged particles) blow away the gas, revealing bright blue star clusters. These stars are about 1 million to 10 million years old. The older populations of stars are not as blue.

A bar of stars, gas, and dust slicing across the core of the galaxy may be instigating most of the star birth in the galaxy's core. The bar funnels material to the galaxy's center, where the most active star formation is taking place. The brightest star clusters reside along an arc near the core.

The remains of about 60 supernova blasts, the deaths of massive stars, can be seen in the image, five times more than known previously in this region. WFC3 identified the remnants of exploded stars. By studying these remnants, astronomers can better understand the nature of the progenitor stars, which are responsible for the creation and dispersal of most of the galaxy's heavy elements.

M83, located in the Southern Hemisphere, is often compared to M51, dubbed the Whirlpool galaxy, in the Northern Hemisphere. Located 15 million light-years away in the constellation Hydra, M83 is two times closer to Earth than M51.

Credit for ground-based image: European Southern Observatory

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. Goddard manages the telescope. The Space Telescope Science Institute conducts Hubble science operations. The institute is operated for NASA by the Association of Universities for Research in Astronomy, Inc. in Washington, and is an International Year of Astronomy 2009 program partner.

Images and more information about M83 are available at:

› HubbleSite
› Space Telescope Science Institute
› NASA Hubble page

› Series of STSI images zooming in on M83

NASA Spitzer Observes a Chaotic Planetary System

An infrared image of the young star HR 8799
Before our planets found their way to the stable orbits they circle in today, they wiggled and jostled about like unsettled children. Now, NASA's Spitzer Space Telescope has found a young star with evidence for the same kind of orbital hyperactivity. Young planets circling the star are thought to be disturbing smaller comet-like bodies, causing them to collide and kick up a huge halo of dust.

The star, called HR 8799, was in the news last November 2008, for being one of the first of two stars with imaged planets. Ground-based telescopes at the W.M. Keck Observatory and the Gemini Observatory, both in Hawaii, took images of three planets orbiting in the far reaches of the system, all three being roughly 10 times the mass of Jupiter. Another imaged planet was also announced at the same time around the star Fomalhaut, as seen by NASA's Hubble Space Telescope. Both HR 8799 and Fomalhaut are younger and more massive than our sun.

Astronomers had previously used both Spitzer and Hubble to image a rotating disk of planetary debris around Fomalhaut, which is 25 light-years from Earth. HR 8799 is about five times farther away, so scientists weren't sure if Spitzer would be able to capture a picture of its disk. To their amazement and delight, Spitzer succeeded. The picture can be seen online at .

The Spitzer team, led by Kate Su of the University of Arizona, Tucson, says the giant cloud of fine dust around the disk is very unusual. They say this dust must be coming from collisions among small bodies similar to the comets or icy bodies that make up today's Kuiper Belt objects in our solar system. The gravity of the three large planets is throwing the smaller bodies off course, causing them to migrate around and collide with each other. Astronomers think the three planets might have yet to reach their final stable orbits, so more violence could be in store.

"The system is very chaotic and collisions are spraying up a huge cloud of fine dust," said Su. "What's exciting is that we have a direct link between a planetary disk and imaged planets. We've been studying disks for a long time, but this star and Fomalhaut are the only two examples of systems where we can study the relationships between the locations of planets and the disks."

When our solar system was young, it went through similar planet migrations. Jupiter and Saturn moved around quite a bit, throwing comets around, sometimes into Earth. Some say the most extreme part of this phase, called the late heavy bombardment, explains how our planet got water. Wet, snowball-like comets are thought to have crashed into Earth, delivering life's favorite liquid.

The Spitzer results were published in the Nov. 1 issue of Astrophysical Journal. The observations were made before Spitzer began its "warm" mission and used up its liquid coolant.

Tuesday, November 10, 2009

NASA West Point Welcomes Home One of Their Heroes

On the morning of Oct. 2, as he had done so many times before, Bill McArthur arrived early for his mechanical engineering class at the U. S. Military Academy at West Point. But this time he wasn’t a student, he was the teacher and he wasn’t wearing the black and gray uniform of a cadet, he was wearing the iconic blue flight suit of an astronaut. Almost four decades after graduating from West Point he had been invited to return to his alma mater as part of the Army’s annual homecoming celebration and NASA’s Hometown Heroes campaign.

McArthur graduated from West Point in 1973 and was commissioned as a Second Lieutenant in the U.S. Army. He returned to teach at the distinguished military academy in 1983 and in 1987 the Army re-assigned him to work for NASA as a Space Shuttle vehicle integration test engineer at Johnson Space Center. In 1990, he was selected as an astronaut and flew on three shuttle missions followed by a six-month stay onboard the International Space Station (ISS). He now serves as the manager of the Orbiter Project Office for the Space Shuttle Program at JSC.

McArthur’s return to West Point was one of three Hometown Heroes events occurring the weekend of Oct. 3. Throughout the 2009 fall football season, astronauts have been returning to their alma maters to help celebrate two major NASA milestones - the 10th anniversary of the space station in orbit and the 40th anniversary of the Apollo 11 lunar landing. Recognition during the football game along with media, community and educational outreach events are all part of the campaign.

McArthur began his West Point visit the morning of Oct. 2 by sharing the story of his life onboard the space station with Army cadets during three separate mechanical engineering classes. Next was a lunch presentation to a packed conference room of cadets and faculty members before heading off base to spend the afternoon at nearby Highland Falls Middle School (HFMS). About 400 students, teachers and parents listened intently as McArthur stressed the power of how a good education can help dreams, like his to become an astronaut and eventually live in space, come true.

“Col. Bill McArthur's presentation at our school was for most, if not all, a once in a lifetime opportunity,” said Ellen Connors, principal of HFMS. “To be witness to a first-hand account of the space program's history is a memory that all will hold in their hearts and minds forever. I assure you that you've made 400 new friends and fans!”

“When she got home Friday, my daughter took one of her old school pictures out of a frame and replaced it with her autographed picture of Col. McArthur,” added Mary Jane Pitt, parent of an HFMS sixth grader. “It's now hanging proudly in her room.”

After signing autographs for more than an hour, McArthur ended his visit by presenting the HFMS staff with a photo of the Highland Falls, NY area taken from the space station.

On Oct. 3, game day at West Point, McArthur spent the morning talking to parents and faculty during a pre-game breakfast and at the Army cadet review that followed. Next was an autograph session just outside Michie Stadium, home of the Army Black Knights football team. Just before kickoff, McArthur joined the more than 24,000 fans in the stadium as the Black Nights hosted the Tulane Green Wave.

At halftime, McArthur was interviewed by the Army radio broadcast team and between the third and fourth quarter was recognized on the field where he received a standing ovation from the fans. “I feel totally recharged,” McArthur said, standing on the sidelines afterwards with a huge smile on his face.

"What strikes me most about Bill MacArthur is that he always has time for everyone,” said Joe Tombrello, deputy director of Public Affairs and Communications for the U.S. Military Academy. “Whether teaching a class to cadets, discussing old times with a classmate, accepting a handshake from a well-wisher, or simply signing an autograph for a 5th grader whose dad is stationed in Korea, Bill made everyone feel as though they were the most important thing in his life at the time.”

And as the sun set on an empty Michie Stadium, McArthur was easy to spot in his blue flight suit just outside the gate talking with cadets and their families and sharing the excitement of both his life as an astronaut and the future of NASA’s space exploration opportunities.

Sunday, November 8, 2009

NASA and X Prize Announce Winners of Lunar Lander Challenge

NASA will award $1.65 million in prize money Thursday to a pair of innovative aerospace companies that successfully simulated landing a spacecraft on the moon and lifting off again.

NASA’s Centennial Challenges program will give a $1 million first prize to Masten Space Systems of Mojave, Calif., and a $500,000 second prize to Armadillo Aerospace of Rockwall, Tex., for their Northrop Grumman Lunar Lander Challenge flights. The competition was managed by the X PRIZE Foundation. The Northrop Grumman Corporation is a commercial sponsor that provided operating funds for the contest to the X PRIZE Foundation.

An awards ceremony for the winning teams will be held at noon on Nov. 5 in room 2325 of the Rayburn House Office Building in Washington. Journalists should contact Sonja Alexander at 202-358-1761 for more information about the ceremony.

The Northrop Grumman Lunar Lander Challenge involves building and flying a rocket-powered vehicle that simulates the flight of a vehicle on the moon. The lander must take off vertically then travel horizontally, flying a mission profile designed to demonstrate both power and control before landing accurately at another spot. The same vehicle then must take off again, travel horizontally back to its original takeoff point and land successfully, all within a two-hour-and-15-minute time period.

The challenge requires exacting control and navigation, as well as precise control of engine thrust, all done automatically. The rocket's engine must be started twice in a short time with no ground servicing other than refueling. This represents the technical challenges involved in operating a reusable vehicle that could land on the moon.

The prize purse is divided into first and second prizes for Level 1 and Level 2. Level 1 requires a flight duration of at least 90 seconds on each flight and Level 2 requires a duration of at least 180 seconds. One of the landings for a Level 2 attempt must be made on a simulated lunar terrain with rocks and craters.

Masten Space Systems met the Level 2 requirements by achieving accurate landings and captured the first place prize during flights of their "Xoie" (pronounced "Zoey") vehicle Oct. 30 at the Mojave Air and Space Port. Masten also claimed a $150,000 prize as part of the Level 1 competition.

Armadillo Aerospace was the first team to qualify for the Level 2 prize with successful flights of its Scorpius rocket Sept. 12 in Caddo Mills, Tex. Armadillo placed second in the Level 2 competition, earning a $500,000 prize.

The average landing accuracy determined which teams would receive first and second place prizes. The Masten team achieved an average accuracy of 7.5 inches while Armadillo Aerospace's average accuracy was 34 inches.

The events of the past two months have brought the four-year Northrop Grumman Lunar Lander Challenge to a conclusion. All $2 million in prize money has been awarded.

"The Northrop Grumman Lunar Lander Challenge has had its intended impact, with impressive performances by multiple teams representing a new generation of aerospace entrepreneurs" said Andrew Petro, NASA's Centennial Challenge program manager at NASA Headquarters in Washington. "These companies have demonstrated reusable vehicles with rapid turnaround and a surprising degree of precision in flight, and they have done all this at a much lower cost than many thought possible."

Four teams had been in pursuit of the 2009 Lunar Lander Challenge prizes during the competition that opened in July. The BonNova team dropped out of the competition last week. Unreasonable Rocket, a father-and-son team from Solana Beach, Calif., conducted flight attempts during the final days of the competition but did not complete any qualifying flights.

In the Level 1 competition, Armadillo Aerospace previously claimed the first place prize of $350,000 in 2008. Masten Space Systems qualified for the remaining second place prize on Oct. 7, 2009, with an average landing accuracy of 6.3 inches. Because there were no other qualifying Level 1 flights this year, the Masten team will receive the second place prize of $150,000.

NASA's Centennial Challenges program's goals are to drive progress in aerospace technology that is of value to NASA's missions; encourage participation of independent teams, individual inventors, student groups and private companies of all sizes in aerospace research and development; and find innovative solutions to technical challenges through competition and cooperation.

The Northop Grumman Lunar Lander Challenge is one of six Centennial Challenges managed by NASA's Innovative Partnership Program. The competition was managed for NASA at no cost to the taxpayer by the X PRIZE Foundation under a Space Act Agreement. NASA provided all of the prize funds.

For more information on Centennial Challenges, visit:

For more information about NASA and agency programs, visit:

Friday, November 6, 2009

New Celestial Map Gives Directions for GPS

This is an artist's concept of a quasar (bright area with rays) embedded in the center of a galaxyMany of us have been rescued from unfamiliar territory by directions from a Global Positioning System (GPS) navigator. GPS satellites send signals to a receiver in your GPS navigator, which calculates your position based on the location of the satellites and your distance from them. The distance is determined by how long it took the signals from various satellites to reach your receiver.

The system works well, and millions rely on it every day, but what tells the GPS satellites where they are in the first place?

"For GPS to work, the orbital position, or ephemeris, of the satellites has to be known very precisely," said Dr. Chopo Ma of NASA's Goddard Space Flight Center in Greenbelt, Md. "In order to know where the satellites are, you have to know the orientation of the Earth very precisely."

This is not as obvious as simply looking at the Earth – space is not conveniently marked with lines to determine our planet's position. Even worse, "everything is always moving," says Ma. Earth wobbles as it rotates due to the gravitational pull (tides) from the moon and the sun. Even apparently minor things like shifts in air and ocean currents and motions in Earth's molten core all influence our planet's orientation.

Just as you can use landmarks to find your place in a strange city, astronomers use landmarks in space to position the Earth. Stars seem the obvious candidate, and they were used throughout history to navigate on Earth. "However, for the extremely precise measurements needed for things like GPS, stars won't work, because they are moving too," says Ma.

What is needed are objects so remote that their motion is not detectable. Only a couple classes of objects fit the bill, because they also need to be bright enough to be seen over incredible distances. Things like quasars, which are typically brighter than a billion suns, can be used. Many scientists believe these objects are powered by giant black holes feeding on nearby gas. Gas trapped in the black hole's powerful gravity is compressed and heated to millions of degrees, giving off intense light and/or radio energy.

A sky map of the 295 defining sources of ICRF2Most quasars lurk in the outer reaches of the cosmos, over a billion light years away, and are therefore distant enough to appear stationary to us. For comparison, a light year, the distance light travels in a year, is almost six trillion miles. Our entire galaxy, consisting of hundreds of billions of stars, is about 100,000 light years across.

A collection of remote quasars, whose positions in the sky are precisely known, forms a map of celestial landmarks in which to orient the Earth. The first such map, called the International Celestial Reference Frame (ICRF), was completed in 1995. It was made over four years using painstaking analysis of observations on the positions of about 600 objects.

Ma led a three-year effort to update and improve the precision of the ICRF map by scientists affiliated with the International Very Long Baseline Interferometry Service for Geodesy and Astrometry (IVS) and the International Astronomical Union (IAU). Called ICRF2, it uses observations of approximately 3,000 quasars. It was officially recognized as the fundamental reference system for astronomy by the IAU in August, 2009.

Making such a map is not easy. Despite the brilliance of quasars, their extreme distance makes them too faint to be located accurately with a conventional telescope that uses optical light (the light that we can see). Instead, a special network of radio telescopes is used, called a Very Long Baseline Interferometer (VLBI).

The larger the telescope, the better its ability to see fine detail, called spatial resolution. A VLBI network coordinates its observations to get the resolving power of a telescope as large as the network. VLBI networks have spanned continents and even entire hemispheres of the globe, giving the resolving power of a telescope thousands of miles in diameter. For ICRF2, the analysis of the VLBI observations reduced uncertainties in position to angles as small as 40 microarcseconds, about the thickness of a 0.7 millimeter mechanical pencil lead in Los Angeles when viewed from Washington. This minimum uncertainty is about five times better than the ICRF, according to Ma.

These networks are arranged on a yearly basis as individual radio telescope stations commit time to make coordinated observations. Managing all these coordinated observations is a major effort by the IVS, according to Ma.

Additionally, the exquisite precision of VLBI networks makes them sensitive to many kinds of disturbances, called noise. Differences in atmospheric pressure and humidity caused by weather systems, flexing of the Earth's crust due to tides, and shifting of antenna locations from plate tectonics and earthquakes all affect VLBI measurements. "A significant challenge was modeling all these disturbances in computers to take them into account and reduce the noise, or uncertainty, in our position observations," said Ma.

Another major source of noise is related to changes in the structure of the quasars themselves, which can be seen because of the extraordinary resolution of the VLBI networks, according to Ma.

The ICRF maps are not only useful for navigation on Earth; they also help us find our way in space -- the ICRF grid and some of the objects themselves are used to assist spacecraft navigation for interplanetary missions, according to Ma.

Despite its usefulness for things like GPS, the primary application for the ICRF maps is astronomy. Researchers use the ICRF maps as driving directions for telescopes. Objects are referenced with coordinates derived from the ICRF so that astronomers know where to find them in the sky.

Also, the optical light visible to our eyes is only a small part of the electromagnetic radiation produced by celestial objects, which ranges from less-energetic, low-frequency radiation, like radio and microwaves, through optical light to highly energetic, high-frequency radiation like X-rays and gamma-rays.

Astronomers use special detectors to make images of objects producing radiation our eyes can't see. Even so, since things in space can have extremely different temperatures, objects that generate radiation in one frequency band, say optical, do not necessarily produce radiation in another, perhaps radio. The main scientific use of the ICRF maps is a precise grid for combining observations of objects taken using different frequencies and accurately locating them relative to each other in the sky.

Astronomers also use the frame as a backdrop to record the motion of celestial objects closer to us. Tracing how stars and other objects move provides clues to their origin and evolution.

A radio telescope at the Kokee Park Geophysical ObservatoryThe next update to the ICRF may be done in space. The European Space Agency plans to launch a satellite called Gaia in 2012 that will observe about a half-million quasars. Gaia uses an optical telescope, but because it is above the atmosphere, the satellite will be able to clearly see these faint objects and precisely locate them in the sky. The mission will use quasars that are optically bright, many of which are too dim in radio to be useful for the VLBI networks. The project expects to have enough observations by 2018 to 2020 to produce the next-generation ICRF.

ICRF2 involved researchers from Australia, Austria, China, France, Germany, Italy, Russia, Ukraine, and the United States; and was funded by organizations from these countries, including NASA. The analysis efforts are coordinated by the IVS. The IAU officially adopts the ICRF maps and recommends their occasional updates.

Wednesday, November 4, 2009

Robot Armada Might Scale New Worlds

Artist concept of orbiter, airblimps, rovers and robots working togetherAn armada of robots may one day fly above the mountain tops of Saturn's moon Titan, cross its vast dunes and sail in its liquid lakes.

Wolfgang Fink, visiting associate in physics at the California Institute of Technology in Pasadena says we are on the brink of a great paradigm shift in planetary exploration, and the next round of robotic explorers will be nothing like what we see today.

"The way we explore tomorrow will be unlike any cup of tea we've ever tasted," said Fink, who was recently appointed as the Edward and Maria Keonjian Distinguished Professor in Microelectronics at the University of Arizona, Tucson. "We are departing from traditional approaches of a single robotic spacecraft with no redundancy that is Earth-commanded to one that allows for having multiple, expendable low-cost robots that can command themselves or other robots at various locations at the same time."

Fink and his team members at Caltech, the U.S. Geological Survey and the University of Arizona are developing autonomous software and have built a robotic test bed that can mimic a field geologist or astronaut, capable of working independently and as part of a larger team. This software will allow a robot to think on its own, identify problems and possible hazards, determine areas of interest and prioritize targets for a close-up look.

The way things work now, engineers command a rover or spacecraft to carry out certain tasks and then wait for them to be executed. They have little or no flexibility in changing their game plan as events unfold; for example, to image a landslide or cryovolcanic eruption as it happens, or investigate a methane outgassing event.

"In the future, multiple robots will be in the driver's seat," Fink said. These robots would share information in almost real time. This type of exploration may one day be used on a mission to Titan, Mars and other planetary bodies. Current proposals for Titan would use an orbiter, an air balloon and rovers or lake landers.

In this mission scenario, an orbiter would circle Titan with a global view of the moon, with an air balloon or airship floating overhead to provide a birds-eye view of mountain ranges, lakes and canyons. On the ground, a rover or lake lander would explore the moon's nooks and crannies. The orbiter would "speak" directly to the air balloon and command it to fly over a certain region for a closer look. This aerial balloon would be in contact with several small rovers on the ground and command them to move to areas identified from overhead.

"This type of exploration is referred to as tier-scalable reconnaissance," said Fink. "It's sort of like commanding a small army of robots operating in space, in the air and on the ground simultaneously."

A rover might report that it's seeing smooth rocks in the local vicinity, while the airship or orbiter could confirm that indeed the rover is in a dry riverbed - unlike current missions, which focus only on a global view from far above but can't provide information on a local scale to tell the rover that indeed it is sitting in the middle of dry riverbed.

A current example of this type of exploration can best be seen at Mars with the communications relay between the rovers and orbiting spacecraft like the Mars Reconnaissance Orbiter. However, that information is just relayed and not shared amongst the spacecraft or used to directly control them.

"We are basically heading toward making robots that command other robots," said Fink, who is director of Caltech's Visual and Autonomous Exploration Systems Research Laboratory, where this work has taken place.

"One day an entire fleet of robots will be autonomously commanded at once. This armada of robots will be our eyes, ears, arms and legs in space, in the air, and on the ground, capable of responding to their environment without us, to explore and embrace the unknown," he added.

Papers describing this new exploration are published in the journal "Computer Methods and Programs in Biomedicine" and in the Proceedings of the SPIE.

For more information on this work, visit . More information on JPL missions is at http:/ .