NASA's NuSTAR Sees Rare Blurring of Black Hole Light

NASA - NuSTAR Mission patch.

August 13, 2014

NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) has captured an extreme and rare event in the regions immediately surrounding a supermassive black hole. A compact source of X-rays that sits near the black hole, called the corona, has moved closer to the black hole over a period of just days.

"The corona recently collapsed in toward the black hole, with the result that the black hole's intense gravity pulled all the light down onto its surrounding disk, where material is spiraling inward," said Michael Parker of the Institute of Astronomy in Cambridge, United Kingdom, lead author of a new paper on the findings appearing in the Monthly Notices of the Royal Astronomical Society.

Image above: The regions around supermassive black holes shine brightly in X-rays. Some of this radiation comes from a surrounding disk, and most comes from the corona, pictured here in this artist's concept as the white light at the base of a jet. This is one of a few possible shapes predicted for coronas. Image Credit: NASA/JPL-Caltech.

As the corona shifted closer to the black hole, the gravity of the black hole exerted a stronger tug on the X-rays emitted by it. The result was an extreme blurring and stretching of the X-ray light. Such events had been observed previously, but never to this degree and in such detail.

Supermassive black holes are thought to reside in the centers of all galaxies. Some are more massive and rotate faster than others. The black hole in this new study, referred to as Markarian 335, or Mrk 335, is about 324 million light-years from Earth in the direction of the Pegasus constellation. It is one of the most extreme of the systems for which the mass and spin rate have ever been measured. The black hole squeezes about 10 million times the mass of our sun into a region only 30 times the diameter of the sun, and it spins so rapidly that space and time are dragged around with it.

Even though some light falls into a supermassive black hole never to be seen again, other high-energy light emanates from both the corona and the surrounding accretion disk of superheated material. Though astronomers are uncertain of the shape and temperature of coronas, they know that they contain particles that move close to the speed of light.

NASA's Swift satellite has monitored Mrk 335 for years, and recently noted a dramatic change in its X-ray brightness. In what is called a target-of-opportunity observation, NuSTAR was redirected to take a look at high-energy X-rays from this source in the range of 3 to 79 kiloelectron volts. This particular energy range offers astronomers a detailed look at what is happening near the event horizon, the region around a black hole from which light can no longer escape gravity's grasp.

Image above: This plot of data captured by NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR, shows X-ray light streaming from regions near a supermassive black hole known as Markarian 335. Image Credit: NASA/JPL-Caltech/Institute for Astronomy, Cambridge.

Follow-up observations indicate that the corona still is in this close configuration, months after it moved. Researchers don't know whether and when the corona will shift back. What is more, the NuSTAR observations reveal that the grip of the black hole's gravity pulled the corona's light onto the inner portion of its superheated disk, better illuminating it. Almost as if somebody had shone a flashlight for the astronomers, the shifting corona lit up the precise region they wanted to study.

The new data could ultimately help determine more about the mysterious nature of black hole coronas. In addition, the observations have provided better measurements of Mrk 335's furious relativistic spin rate. Relativistic speeds are those approaching the speed of light, as described by Albert Einstein's theory of relativity.

"We still don't understand exactly how the corona is produced or why it changes its shape, but we see it lighting up material around the black hole, enabling us to study the regions so close in that effects described by Einstein's theory of general relativity become prominent," said NuSTAR Principal Investigator Fiona Harrison of the California Institute of Technology (Caltech) in Pasadena. "NuSTAR's unprecedented capability for observing this and similar events allows us to study the most extreme light-bending effects of general relativity."

NASA's Nuclear Spectroscopic Telescope Array (NuSTAR). Image Credit: NASA/JPL-Caltech

NuSTAR is a Small Explorer mission led by Caltech and managed by NASA's Jet Propulsion Laboratory (JPL) in Pasadena for NASA's Science Mission Directorate in Washington. The spacecraft was built by Orbital Sciences Corporation in Dulles, Virginia. Its instrument was built by a consortium including Caltech, JPL, the University of California, Berkeley, Columbia University, New York, NASA's Goddard Space Flight Center, Greenbelt, Maryland, the Danish Technical University in Denmark, Lawrence Livermore National Laboratory in Livermore, California, ATK Aerospace Systems in Goleta, California, and with support from the Italian Space Agency (ASI) Science Data Center.

NuSTAR's mission operations center is at UC Berkeley, with the ASI providing its equatorial ground station located in Malindi, Kenya. The mission's outreach program is based at Sonoma State University, Rohnert Park, California. NASA's Explorer Program is managed by Goddard. JPL is managed by Caltech for NASA.

For more information on NuSTAR, visit: http://www.nasa.gov/nustar

Images (mentioned), Text, Credits: NASA / J.D. Harrington / JPL / Whitney Clavin.

Greetings, Orbiter.ch

Space Station Fix-It Demo for Satellites Gets Hardware for 2.0 Update

ISS - International Space Station patch.

August 12, 2014

Who doesn’t love an upgrade? Newer, better and oh so shiny is great, but what’s really fantastic is when a change unlocks new possibilities. That’s the case with NASA’s fix-it investigation on the International Space Station, the Robotic Refueling Mission (RRM). The award-winning endeavor moved one step closer to its 2.0 update with the delivery of new RRM hardware aboard the European Automated Transfer Vehicle-5, which docked with the space station today. The RRM module, affixed to an exterior space station platform since 2011, now awaits the robotic transfer of two new task boards and a borescope inspection tool that will equip RRM for a new round of satellite-servicing demonstrations.

“The Robotic Refueling Mission is about to get a refresh, and we couldn’t be more excited,” explains Benjamin Reed, deputy project manager of the Satellite Servicing Capabilities Office, the team responsible for RRM’s development and operations on orbit.

Image above: View of the Robotic Refueling Mission (RRM) module outside of the International Space Station as photographed by an Expedition 28 crew member in 2011. Image Credit: NASA.

“This is the beauty of doing research on the space station. We’re not tied to the original hardware complement we sent up three years ago. The cadence of space station supply flights gives us the opportunity to swap equipment so we can tackle a new set of technology demonstrations.”

Since 2011, the duo of RRM and Dextre—the Canadian Space Agency robot that acts as a “handyman” for external station activities—has been steadily evaluating a set of NASA-developed, game-changing technologies that would enable remotely controlled robots to eventually repair and service spacecraft in orbit. The overarching challenge facing the NASA RRM team is devising and manufacturing new robotic, teleoperated tools and techniques to service spacecraft that were not designed for in-flight service.

Robotic refueling and the tasks accompanying it – including blanket cutting, wire cutting and cap and fastener removal – were the primary focus of RRM’s first set of technology demonstrations.

Image above: A new complement of hardware will outfit NASA’s Robotic Refueling Mission (center on International Space Station platform) for a fresh set of satellite-servicing demonstrations. Image Credit: NASA.

In its second phase of activities, RRM will move past its refueling roots to test out the inspection capabilities of a new space tool named VIPIR, the Visual Inspection Poseable Invertebrate Robot. The team will also tackle the intermediary steps leading toward spacecraft cryogen replenishment and host a demonstration of next-generation solar cell technology and a carbon nanotube experiment.

“The common thread is building up NASA’s collection of enabling satellite-servicing capabilities,” says Reed. “Every capability translates into another option a satellite owner could potentially choose to keep his or her satellite operating longer and performing optimally.”

Image above: A new RRM tool named VIPIR – the Visual Inspection Poseable Invertebrate Robot – was delivered to the International Space Station aboard the Automated Transfer Vehicle-5. Image Credit: NASA.

Longer-living spacecraft would in turn translate into extended services for people on Earth who rely on these satellites for timely, accurate data. “Satellites are the unseen powerhouses that quietly generate and move the data we rely on every day of our lives: weather reports, satellite television, GPS and communications support," explained Reed.

The newly delivered RRM hardware, consisting of a task board and the VIPIR tool, joins two other pieces that were delivered to space station in August 2013 by a Japanese cargo vehicle. The space station crew will stow these new RRM components inside the orbiting research center until the team can use Dextre to transfer and install them robotically on the RRM module. This transfer and the subsequent RRM-Phase 2 operations are being scheduled.

Related links:

Robotic Refueling Mission (RRM): http://ssco.gsfc.nasa.gov/robotic_refueling_mission.html

Automated Transfer Vehicle-5: http://www.esa.int/Our_Activities/Human_Spaceflight/ATV

Dextre—the Canadian Space Agency robot: http://www.asc-csa.gc.ca/eng/iss/dextre/

Carbon nanotube experiment: http://www.nasa.gov/content/goddard/super-black-nano-coating-to-be-tested-for-the-first-time-in-space/

For more information about the International Space Station (ISS), visit: http://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Text, Credits: NASA’s Goddard Space Flight Center / Adrienne Alessandro.

Cheers, Orbiter.ch

ATV completes final automated docking

ESA - ATV-5 Georges Lemaître Mission patch.

12 August 2014

In a flawless demonstration of technology and skill, ESA’s fifth and final ATV, Georges Lemaître, docked with the International Space Station today, fixing itself firmly for a six-month resupply and reboost mission.

The fully automated docking came at 13:30 GMT (15:30 CEST), just a few moments after the cargo vessel’s extended probe made contact with the cone on the aft of Russia’s Zvezda module.

Docking of ATV Georges Lemaître to ISS

After contact, a series of hooks latched and closed, making a firm mechanical connection with the Station. Later, data and electrical connections were created, allowing ATV to draw power from the orbital outpost and for the Station computers to talk directly to ATV.

The sequence came at the end of several hours of automated manoeuvres, during which ATV powered itself through a series of waypoints starting some 40 km behind and just below the Station.

ATV navigates itself

“From 39 km to just 250 m from the Station, ATV navigated itself using relative satnav signals, in which both the Station and ATV compare their positions using GPS,” says Jean-Michel Bois, leading the ESA operations team at the ATV Control Centre in Toulouse, France. Mission operations are run jointly with France’s CNES space agency.

“For the final 250 m, ATV navigated using a ‘videometer’ and ‘telegoniometer’, which use laser pulses to calculate the distance and orientation to the Station.”

The entire process was completed flawlessly, carefully monitored by the ground team and ESA astronaut Alexander Gerst and cosmonaut Sasha Skvortsov on the Station.

ATV-5 in orbit prior to docking

"European cargo spaceship Georges Lemaître has successfully docked to the ISS and the crew sends their congratulations to all the brilliant engineering teams on the ground and in ATV Control Center in Toulouse and in Moscow and to those who have contributed over the last 20 years to the development of one of the most advanced resupply vessels that circles our planet," said ESA astronaut Alexander Gerst on board the ISS.

"While this is the last of the ATV flights, the know-how and technology will soon fly again as early as 2017. NASA’s Orion spacecraft with the European Service Module are paving the way for the next generation of space exploration."

The crew will open the hatch and enter briefly over the next day, installing a fan to freshen the internal air before ATV is made ready for daily use.

One of ATV’s most crucial capabilities – using its thrusters to reboost the Station’s altitude – will be tested in just two days, with a test burn scheduled for 14 August.

Teams perform magnificently

“The final arrival of Europe’s ATV space freighter was almost anticlimactic, as the vessel’s made-in-Europe docking technology performed perfectly for the fifth and final time,” said Massimo Cislaghi, ATV-5 mission manager.

“Most importantly, the crew in space and the ESA, CNES and industry teams on ground performed magnificently, and it is thanks to their dedication over the life of this project that ATVs have won a reputation for being some of the most reliable and dependable space vessels ever flown.”

ATV-CC teams during rendezvous

Named after the Belgian scientist who formulated the Big Bang Theory, ATV Georges Lemaître lifted off at 23:47 GMT on 29 July (01:47 CEST 30 July) on an Ariane 5 rocket from Europe’s Spaceport in Kourou, French Guiana.

The vehicle is carrying 6602 kg of freight, including 2680 kg of dry cargo and 3921 kg of water, propellants and gases.

The cargo includes complex scientific hardware, such as the electromagnetic levitator for experiments to improve industrial casting processes. The unit will allow finer metal castings and more precise measurements than can be obtained on Earth, where readings are affected by gravity.

Related links:

More information about ATV: http://www.esa.int/Our_Activities/Human_Spaceflight/ATV

ATV blog: http://blogs.esa.int/atv

ATV Control Centre: http://www.esa.int/Our_Activities/Human_Spaceflight/ATV/ATV_Control_Centre

Images, Video, Text, Credits: ESA / NASA / CNES / M. Pedoussaut.

Greetings, Orbiter.ch

ATV-5 Approaching Station While Crew Preps for Spacewalk

ISS - Expedition 40 Mission patch.

August 11, 2014

The six-member Expedition 40 crew is conducting its normal suite of international science and maintenance while waiting for Europe’s Automated Transfer Vehicle-5 (ATV-5) to dock Tuesday at 9:30 a.m. EDT.

Read about the launch of the ATV-5: http://orbiterchspacenews.blogspot.ch/2014/07/europes-fifth-and-final-resupply-ship.html

A pair of cosmonauts is counting down to next week’s Russian spacewalk to deploy a nanosatellite and retrieve external science gear attached to the Zvezda service module’s hull. Flight Engineers Alexander Skvortsov and Oleg Artemyev sized their Orlan spacesuits and checked for leaks in advance of the six-hour, 15-minute spacewalk scheduled for Aug. 18.

Astronauts Steve Swanson, Reid Wiseman and Alexander Gerst started their morning by attaching themselves to a device to measure their body mass. The Space Linear Acceleration Mass Measurement Device (SLAMMD) applies a known force to a crew member and uses the resulting acceleration, Newton’s Second Law of Motion, to calculate mass.

Read about the SLAMMD: http://www.nasa.gov/mission_pages/station/research/experiments/640.html

Gerst then performed some light plumbing work and reviewed the ATV-5 cargo transfer list. After lunch he and Wiseman joined Commander Swanson for an ATV-5 hardware transfer tag up. The European Space Agency astronaut from Germany then went back to work on more plumbing, draining water from the Water Recycling System in the Harmony node.

Wiseman continued his morning work troubleshooting a lithium-ion battery charger in a U.S. spacesuit. The NASA astronaut then had an interview with WJLA-TV in Washington, D.C. and talked about adjusting to life in space and tweeting from the International Space Station.

View Reid Wiseman’s Twitter account (@Astro_Reid): https://twitter.com/astro_reid

Image above: Reid Wiseman talks to WJLA-TV in Washington, D.C. Image Credit: NASA TV.

He spent the rest of his afternoon working on science gear inside the Combustion Integrated Rack for maintenance. He replaced a fuel reservoir that contains the liquid fuel necessary for the rack’s droplet combustion experiments.

Read about the Combustion Integrated Rack: http://www.nasa.gov/mission_pages/station/research/experiments/326.html

The commander worked on a plant experiment inside the Japanese Kibo laboratory, conducting a run for the Resist Tubule botany study. Swanson then stowed tools gathered for a U.S. spacewalk that was postponed to wait for new Long Life Batteries being delivered to the station aboard the SpaceX-4 commercial resupply services flight.

Swanson spent the first part of the afternoon on mobility upgrades for the Robonaut 2 humanoid robot with an eye to install its legs at a later date. Investigators are exploring the possibility that Robonaut could perform tasks too dangerous or mundane for an astronaut. After that, he started up a SPHERES (Synchronized Position Hold, Engage, Reorient, Experimental Satellites) micro-satellite that used an attached smartphone to map the inside of the Kibo lab.

Read more about SPHERES: http://www.nasa.gov/mission_pages/station/research/experiments/311.html

A trio of cosmonauts was also working on its complement of space station science and upkeep on the Russian side of the orbital laboratory.

Future Expedition 41 commander Max Suraev worked during the morning setting up dosimeters for the Matryoshka radiation exposure experiment. He then made preparations inside Zvezda ahead of Tuesday morning’s arrival of the ATV-5.

Skvortsov and Artemyev joined Suraev for a study of their cardiovascular system, exercising on the Velo-ergometer, or exercise bicycle, under a graded physical load.

Meanwhile, ESA’s ATV-5 is closing in for Tuesday morning’s docking to the space station after a two-week trek. During its slow, deliberate approach to the space station, European flight controllers guided the ATV-5 less than four miles underneath the station, then out front and back over the orbital laboratory to test new rendezvous sensors and laser systems. The advanced technology is being tested for its potential to guide future European spacecraft under development.

For more information about the International Space Station (ISS), visit: http://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Text, Credit: NASA.

Best regards, Orbiter.ch

NASA Carbon Counter Reaches Final Orbit, Returns Data

NASA - OCO-2 Mission patch.

August 11, 2014

Just over a month after launch, the Orbiting Carbon Observatory-2 (OCO-2) -- NASA’s first spacecraft dedicated to studying atmospheric carbon dioxide -- has maneuvered into its final operating orbit and produced its first science data, confirming the health of its science instrument.

Atmospheric carbon dioxide is the leading human-produced greenhouse gas responsible for warming our world. It is a critical natural component of Earth’s carbon cycle. OCO-2 will produce the most detailed picture to date of sources of carbon dioxide, as well as their natural “sinks” -- places on Earth’s surface where carbon dioxide is removed from the atmosphere. The observatory will study how these sources and sinks are distributed around the globe and how they change over time.

Following launch from California’s Vandenberg Air Force Base on July 2, OCO-2 underwent a series of steps to configure the observatory for in-flight operations. Mission controllers established two-way communications with the observatory, stabilized its orientation in space and deployed its solar arrays to provide electrical power. The OCO-2 team then performed a checkout of OCO-2’s systems to ensure they were functioning properly.

Image above: NASA's OCO-2 spacecraft collected "first light” data Aug. 6 over New Guinea. OCO-2’s spectrometers recorded the bar code-like spectra, or chemical signatures, of molecular oxygen or carbon dioxide in the atmosphere. The backdrop is a simulation of carbon dioxide created from GEOS-5 model data. Image Credit: NASA/JPL-Caltech/NASA GSFC.

Through the month of July, a series of propulsive burns was executed to maneuver the observatory into its final 438-mile (705-kilometer), near-polar orbit at the head of the international Afternoon Constellation, or “A-Train,” of Earth-observing satellites. It arrived there on Aug. 3. Operations are now being conducted with the observatory in an orbit that crosses the equator at 1:36 p.m. local time.

The A-Train, the first multi-satellite, formation-flying “super observatory” to record the health of Earth’s atmosphere and surface environment, collects an unprecedented quantity of nearly simultaneous climate and weather measurements. OCO-2 is now followed by the Japanese GCOM-W1 satellite, and then by NASA’s Aqua, CALIPSO, CloudSat and Aura spacecraft, respectively -- all of which fly over the same point on Earth within 16 minutes of each other.

With OCO-2 in its final orbit, mission controllers began cooling the observatory’s three-spectrometer instrument to its operating temperatures. The spectrometer’s optical components must be cooled to near 21 degrees Fahrenheit (minus 6 degrees Celsius) to bring them into focus and limit the amount of heat they radiate. The instrument’s detectors must be even cooler, near minus 243 degrees Fahrenheit (minus 153 degrees Celsius), to maximize their sensitivity.

With the instrument’s optical system and detectors near their stable operating temperatures, the OCO-2 team collected “first light” test data on Aug. 6 as the observatory flew over central Papua New Guinea. The data were transmitted from OCO-2 to a ground station in Alaska, then to NASA’s Goddard Space Flight Center in Greenbelt, Maryland, for initial decoding, and then to NASA’s Jet Propulsion Laboratory in Pasadena, California, for further processing. The test provided the OCO-2 team with its first opportunity to see whether the instrument had reached orbit with the same performance it had demonstrated before launch.

Image above: Artist's rendering of NASA's Orbiting Carbon Observatory (OCO)-2, one of five new NASA Earth science missions set to launch in 2014, and one of three managed by JPL. Image Credit: NASA/JPL-Caltech.

As OCO-2 flies over Earth’s sunlit hemisphere, each spectrometer collects a “frame” three times each second, for a total of about 9,000 frames from each orbit. Each frame is divided into eight spectra, or chemical signatures, that record the amount of molecular oxygen or carbon dioxide over adjacent ground footprints. Each footprint is about 1.3 miles (2.25 kilometers) long and a few hundred yards (meters) wide. When displayed as an image, the eight spectra appear like bar codes -- bright bands of light broken by sharp dark lines. The dark lines indicate absorption by molecular oxygen or carbon dioxide.

“The initial data from OCO-2 appear exactly as expected -- the spectral lines are well resolved, sharp and deep,” said OCO-2 chief architect and calibration lead Randy Pollock of JPL. “We still have a lot of work to do to go from having a working instrument to having a well-calibrated and scientifically useful instrument, but this was an important milestone on this journey.”

Over the next several weeks, the OCO-2 team will conduct a series of calibration activities to characterize fully the performance of the instrument and observatory. In parallel, OCO-2 will routinely record and return up to 1 million science observations each day. These data will be used initially to test the ground processing system and verify its products. The team will begin delivering calibrated OCO-2 spectra data to NASA’s Goddard Earth Sciences Data and Information Services Center for distribution to the global science community and other interested parties before the end of the year. The team will also deliver estimates of carbon dioxide to that same center for distribution in early 2015.

OCO-2 is a NASA Earth System Science Pathfinder Program mission managed by JPL for NASA’s Science Mission Directorate in Washington. Orbital Sciences Corporation in Dulles, Virginia, built the spacecraft bus and provides mission operations under JPL’s leadership. The science instrument was built by JPL, based on the instrument design co-developed for the original OCO mission by Hamilton Sundstrand in Pomona, California. NASA’s Launch Services Program at NASA’s Kennedy Space Center in Florida was responsible for launch management.

NASA monitors Earth's vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

For more information, visit: http://www.nasa.gov/oco2 and http://oco.jpl.nasa.gov

For more information about NASA's Earth science activities in 2014, visit: http://www.nasa.gov/earthrightnow

Images (mentioned), Text, Credits: NASA / Steve Cole / JPL / Alan Buis.

Cheers, Orbiter.ch

NASA’s 3-D Study of Comets Reveals Chemical Factory at Work

NASA logo.

August 11, 2014

A NASA-led team of scientists has created detailed 3-D maps of the atmospheres surrounding comets, identifying several gases and mapping their spread at the highest resolution ever achieved.

“We achieved truly first-of-a-kind mapping of important molecules that help us understand the nature of comets,” said Martin Cordiner, a researcher working in the Goddard Center for Astrobiology at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Cordiner led the international team of researchers.

Almost unheard of for comet studies, the 3-D perspective provides deeper insight into which materials are shed from the nucleus of the comet and which are produced within the atmosphere, or coma. This helped the team nail down the sources of two key organic, or carbon-containing, molecules.

HCN - Inner coma of C/2012 F6 (Lemmon)

Video above: This rotating 3-D map shows how HCN molecules (made of hydrogen, carbon and nitrogen) are released from the nucleus of comet Lemmon and then spread evenly throughout the atmosphere, or coma. Similar maps revealed that HNC and formaldehyde are produced in the coma, rather than the comet's nucleus. Image Credit: Brian Kent/NRAO/AUI/NSF.

The observations were conducted in 2013 on comets Lemmon and ISON using the Atacama Large Millimeter/submillimeter Array, or ALMA, a network of high-precision antennas in Chile. These comets are the first to be studied with ALMA.

The ALMA observatory. Image Credit: ESO

The ALMA observations combine a high-resolution 2-D image of a comet’s gases with a detailed spectrum at each point. From these spectra, researchers can identify the molecules present at every point and determine their velocities (speed plus direction) along the line-of-sight; this information provides the third dimension – the depth of the coma.

“So, not only does ALMA let us identify individual molecular species in the coma, it also gives us the ability to map their locations with great sensitivity,” said Anthony Remijan, a scientist with the National Radio Astronomy Observatory, one of the organizations that operates ALMA, and a co-author of the study.

The researchers reported results for three molecular species, focusing primarily on two whose sources have been difficult to discern (except in comet Halley). The 3-D maps indicated whether each molecule was flowing outward evenly in all directions or coming off in jets or in clumps.

U.S. National Radio Astronomy Observatory (NRAO). Image Credit: NRAO

In each comet, the team found that two species – formaldehyde and HNC (made of one hydrogen, one nitrogen and one carbon) – were produced in the coma. For formaldehyde, this confirmed what researchers already suspected, but the new maps contained enough detail to resolve clumps of the material moving into different regions of the coma day-by-day and even hour-by-hour.

For HNC, the maps settled a long-standing question about the material’s source. Initially, HNC was thought to be pristine interstellar material coming from the nucleus of a comet, whereas later work suggested other possible sources. The new study provided the first proof that HNC is produced during the breakdown of large molecules or organic dust in the coma.

“Understanding organic dust is important, because such materials are more resistant to destruction during atmospheric entry, and some could have been delivered intact to early Earth, thereby fueling the emergence of life,” said Michael Mumma, Director of the Goddard Center for Astrobiology, and a co-author on the study. “These observations open a new window on this poorly known component of cometary organics.”

National Astronomical Observatory of Japan. Image Credit: NAOJ

The observations, published today by the Astrophysical Journal Letters, also were significant because modest comets like Lemmon and ISON contain relatively low concentrations of crucial molecules, making them difficult to probe in depth with Earth-based telescopes. The few comprehensive studies of this kind so far have been conducted on bright, blockbuster comets, such as Hale-Bopp. The present results extend them to comets of only moderate brightness.

This research was funded by the NASA Astrobiology Institute through the Goddard Center for Astrobiology and by NASA’s Planetary Atmospheres and Planetary Astronomy programs. ALMA is an international astronomy facility. Its construction and operations are led on behalf of Europe by the European Southern Observatory, on behalf of North America by the U.S. National Radio Astronomy Observatory (NRAO) and on behalf of East Asia by the National Astronomical Observatory of Japan.

For more information about NASA and agency programs, visit: http://www.nasa.gov

Images (mentioned), Video (mentioned), Text, Credits: NASA’s Goddard Space Flight Center / Elizabeth Zubritsky / NASA’s Goddard Space Flight Center / Nancy Neal-Jones.

Best regards, Orbiter.ch

Saturn's moon Rhea, Epimetheus transiting

NASA / ESA - Cassini International logo.

Aug. 11, 2014

Saturn has a great many more moons than our planet – a whopping 62. A single moon, Titan, accounts for an overwhelming 96% of all the material orbit the planet, with a group of six other smaller moons dominating the rest. The other 55 small satellites whizzing around Saturn make up the tiny remainder along with the gas giant’s famous rings.

One of the subjects of this Cassini image, Rhea, belongs to that group of six. Set against a backdrop showing Saturn and its intricate system of icy rings, Rhea dominates the scene and dwarfs its tiny companion, one of the 55 small satellites known as Epimetheus.

Although they appear to be close to one another, this is a trick of perspective – this view was obtained when Cassini was some 1.2 million km from Rhea, and 1.6 million km from Epimetheus, meaning the moons themselves had a hefty separation of 400 000 km.

However, even if they were nearer to each other, Rhea would still loom large over Epimetheus: at 1528 km across and just under half the size of our own Moon, Rhea is well over 10 times the size of Epimetheus, which is a modest 113 km across.

As is traditional for the earliest discovered moons of Saturn, both are named after figures from Greek mythology: the Titan Rhea (“mother of the gods”) and Prometheus’ brother Epimetheus (“after thinker” or “hindsight”).

This image was taken by Cassini’s narrow-angle camera on 24 March 2010, and processed by amateur astronomer Gordan Ugarković. A monochrome version was previously released by NASA as PIA12638: Big and Small Before Rings.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL manages the mission for NASA's Science Mission Directorate in Washington.

Related link:

PIA12638: Big and Small Before Rings: http://photojournal.jpl.nasa.gov/catalog/PIA12638

For more information about Cassini, visit: http://www.nasa.gov/cassini and
http://saturn.jpl.nasa.gov and http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens

Image data Credit: NASA/JPL-Caltech/Space Science Institute; Processed image copyright: G. Ugarković/Text: ESA.

Greetings, Orbiter.ch