Dawn Heads Toward Final Orbit

NASA - Dawn Mission logo.

Oct. 27, 2015

Mission Status Report

NASA's Dawn spacecraft fired up its ion engine on Friday, Oct. 23, to begin its journey toward its fourth and final science orbit at dwarf planet Ceres. The spacecraft completed two months of observations from an altitude of 915 miles (1,470 kilometers) and transmitted extensive imagery and other data to Earth.

Image above: This mosaic shows Ceres' Occator crater and surrounding terrain from an altitude of 915 miles (1,470 kilometers), as seen by NASA's Dawn spacecraft. Occator is about 60 miles (90 kilometers) across and 2 miles (4 kilometers) deep. Image Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

The spacecraft is now on its way to the final orbit of the mission, called the low-altitude mapping orbit. Dawn will spend more than seven weeks descending to this vantage point, which will be less than 235 miles (380 kilometers) from the surface of Ceres. In mid-December, Dawn will begin taking observations from this orbit, including images at a resolution of 120 feet (35 meters) per pixel.

Image above: Can you guess what's creating those unusual bright spots on Ceres? Image Credit: NASA. Link: http://www.jpl.nasa.gov/dawn/world_ceres/

Of particular interest to the Dawn team is Occator crater, home to Ceres' bright spots. A new mosaic of images from Dawn's third science orbit highlights the crater and surrounding terrain.

More information on the Dawn mission is online at: http://www.nasa.gov/dawn and http://dawn.jpl.nasa.gov

Images (mentioned), Text, Credits: NASA/Tony Greicius/JPL/Elizabeth Landau.

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Black Hole Has Major Flare

NASA - Nuclear Spectroscopic Telescope Array (NuSTAR) logo / NASA - Swift Mission patch.

Oct. 27, 2015

The baffling and strange behaviors of black holes have become somewhat less mysterious recently, with new observations from NASA's Explorer missions Swift and the Nuclear Spectroscopic Telescope Array, or NuSTAR. The two space telescopes caught a supermassive black hole in the midst of a giant eruption of X-ray light, helping astronomers address an ongoing puzzle: How do supermassive black holes flare?

The results suggest that supermassive black holes send out beams of X-rays when their surrounding coronas -- sources of extremely energetic particles  -- shoot, or launch, away from the black holes.

Images above: This diagram shows how a shifting feature, called a corona, can create a flare of X-rays around a black hole. The corona (feature represented in purplish colors) gathers inward (left), becoming brighter, before shooting away from the black hole (middle and right). Astronomers don't know why the coronas shift, but they have learned that this process leads to a brightening of X-ray light that can be observed by telescopes. Images Credits: NASA/JPL-Caltech.

"This is the first time we have been able to link the launching of the corona to a flare," said Dan Wilkins of Saint Mary's University in Halifax, Canada, lead author of a new paper on the results appearing in the Monthly Notices of the Royal Astronomical Society. "This will help us understand how supermassive black holes power some of the brightest objects in the universe."

Supermassive black holes don't give off any light themselves, but they are often encircled by disks of hot, glowing material. The gravity of a black hole pulls swirling gas into it, heating this material and causing it to shine with different types of light. Another source of radiation near a black hole is the corona. Coronas are made up of highly energetic particles that generate X-ray light, but details about their appearance, and how they form, are unclear.

Astronomers think coronas have one of two likely configurations. The "lamppost" model says they are compact sources of light, similar to light bulbs, that sit above and below the black hole, along its rotation axis. The other model proposes that the coronas are spread out more diffusely, either as a larger cloud around the black hole, or as a “sandwich” that envelops the surrounding disk of material like slices of bread. In fact, it's possible that coronas switch between both the lamppost and sandwich configurations.

The new data support the "lamppost" model -- and demonstrate, in the finest detail yet, how the light-bulb-like coronas move. The observations began when Swift, which monitors the sky for cosmic outbursts of X-rays and gamma rays, caught a large flare coming from the supermassive black hole called Markarian 335, or Mrk 335, located 324 million light-years away in the direction of the constellation Pegasus. This supermassive black hole, which sits at the center of a galaxy, was once one of the brightest X-ray sources in the sky.

"Something very strange happened in 2007, when Mrk 335 faded by a factor of 30. What we have found is that it continues to erupt in flares but has not reached the brightness levels and stability seen before," said Luigi Gallo, the principal investigator for the project at Saint Mary's University. Another co-author, Dirk Grupe of Morehead State University in Kentucky, has been using Swift to regularly monitor the black hole since 2007.

Image above: A supermassive black hole is depicted in this artist's concept, surrounded by a swirling disk of material falling onto it. Image Credits: NASA/JPL-Caltech.

In September 2014, Swift caught Mrk 335 in a huge flare. Once Gallo found out, he sent a request to the NuSTAR team to quickly follow up on the object as part of a "target of opportunity" program, where the observatory's previously planned observing schedule is interrupted for important events. Eight days later, NuSTAR set its X-ray eyes on the target, witnessing the final half of the flare event.

After careful scrutiny of the data, the astronomers realized they were seeing the ejection, and eventual collapse, of the black hole's corona.

"The corona gathered inward at first and then launched upwards like a jet," said Wilkins. "We still don't know how jets in black holes form, but it's an exciting possibility that this black hole's corona was beginning to form the base of a jet before it collapsed."

Nuclear Spectroscopic Telescope Array (NuSTAR) spacecraft. Image Credit: NASA

How could the researchers tell the corona moved? The corona gives off X-ray light that has a slightly different spectrum -- X-ray “colors" -- than the light coming from the disk around the black hole. By analyzing a spectrum of X-ray light from Mrk 335 across a range of wavelengths observed by both Swift and NuSTAR, the researchers could tell that the corona X-ray light had brightened -- and that this brightening was due to the motion of the corona.

Coronas can move very fast. The corona associated with Mrk 335, according to the scientists, was traveling at about 20 percent the speed of light. When this happens, and the corona launches in our direction, its light is brightened in an effect called relativistic Doppler boosting.

Putting this all together, the results show that the X-ray flare from this black hole was caused by the ejected corona.

"The nature of the energetic source of X-rays we call the corona is mysterious, but now with the ability to see dramatic changes like this we are getting clues about its size and structure," said Fiona Harrison, the principal investigator of NuSTAR at the California Institute of Technology in Pasadena, who was not affiliated with the study.

Swift spacecraft. Image Credit: NASA

Many other black hole brainteasers remain. For example, astronomers want to understand what causes the ejection of the corona in the first place.

NuSTAR is a Small Explorer mission led by Caltech and managed by NASA's Jet Propulsion Laboratory in Pasadena, California, for NASA's Science Mission Directorate in Washington. NuSTAR was developed in partnership with the Danish Technical University and the Italian Space Agency (ASI). The spacecraft was built by Orbital Sciences Corp., Dulles, Virginia. NuSTAR's mission operations center is at UC Berkeley, and the official data archive is at NASA's High Energy Astrophysics Science Archive Research Center. ASI provides the mission's ground station and a mirror archive. JPL is managed by Caltech for NASA.

For more information about Nuclear Spectroscopic Telescope Array (NuSTAR), visit: http://www.nasa.gov/mission_pages/nustar/main/index.html

For more information about Swift mission, visit: http://www.nasa.gov/mission_pages/swift/main/index.html

Black Holes: http://www.nasa.gov/subject/6895/black-holes

Images (mentioned), Text, Credits: NASA/Tony Greicius/JPL/Whitney Clavin.

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China launches Tianhui-1C Earth observation satellite

CASC - China Aerospace Science and Technology Corporation logo.

Oct. 27, 2015

China successfully launched one of the nation’s Long March 2D rockets on Monday, Oct. 26, 2015, lifting the Tianhui-1C mapping satellite into orbit at 3:10 a.m. EDT (7:10 GMT).

Long March 2D successfully launches Tianhui-1C. Image Credit: Xinhua

Liftoff took place from the Launch Area 4 (LA-4) at the Jiuquan Satellite Launch Center in the northwestern province of Gansu.

China Launches New Mapping Satellite. Video Credit: CCTV+

The Tianhui-1 satellites are built by the Hangtian Dongfanghong Weixing Corporation and the Chinese Academy of Space Technology. They use two three-segment deployable solar arrays for power generation and have precise attitude control and pointing capability. The satellite payload is comprised of a three-dimensional imaging system for the acquisition of stereo imagery and a multi-band camera.

Tianhui-1 satellite. Image Credit: CAST

The stereo imager has a field of view of 25 degrees and achieves a ground resolution of five meters. It is sensitive across a wavelength range of 510 to 690 nanometers. The multi-band camera reaches a resolution of ten meters and covers four spectral channels in the blue, green, red and near infrared bands. Both imaging systems are covering a ground swath of 60 Kilometers.

For more information about China Aerospace Science and Technology Corporation (CASC), visit: http://english.spacechina.com/n16421/index.html

Images (mentioned), Video (mentioned), Text, Credits: CASC/Orbiter.ch Aerospace.

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NASA's EPIC Camera Catches Three Developing Tropical Lows in the Indian Ocean

NOAA / NASA - Deep Space Climate Observatory satellite (DSCOVR) logo.

Oct. 26, 2015

Image above: NASA' EPIC instrument that flies aboard NOAA's DSCOVR satellite captured three tropical low pressure areas developing in the Indian Ocean on October 25 at 05:37 UTC (12:37 a.m. EDT). Image Credits: NASA/NOAA.

In one image from a million miles away, NASA's EPIC Camera captured three developing tropical low pressure areas in the Indian Ocean. Two of the three systems have a medium chance to develop into a tropical depression in the next day or two.

On October 25 and 26 two tropical low pressure areas are spinning in the Northern Indian Ocean, and one in the Southern Indian Ocean. The Earth Polychromatic Imaging Camera or EPIC instrument that flies aboard NOAA's DSCOVR or Deep Space Climate Observatory satellite captured an image showing all three low pressure areas on October 25 at 05:37 UTC (12:37 a.m. EDT).

The DSCOVR spacecraft is located at the Earth-Sun Lagrange-1 (L-1) point giving EPIC a unique angular perspective that will be used in science applications to measure ozone, aerosols, cloud reflectivity, cloud height, vegetation properties, and UV radiation estimates at Earth's surface. DSCOVR orbits about 1 million miles from Earth. For more information about DSCOVR, visit: http://www.nesdis.noaa.gov/DSCOVR/.

In the Northern Indian Ocean System 93B was located east of the southern India peninsula. System 93B was near 6.6 degrees north latitude and 83.1 degrees east longitude. That's about 190 nautical miles east of Colombo, Sri Lanka. Despite this low pressure area having a weak low-level center of circulation with disorganized convection (rising air that forms the thunderstorms that make up a tropical cyclone), it is in an environment with low to moderate vertical wind shear. However, because it is close to Sri Lanka, its proximity to land is hindering development. System 93B has a low chance for development in the next two days.

 DSCOVR or Deep Space Climate Observatory satellite. Image Credits:NASA/NOAA

On the western side of the southern India peninsula was System 94A. System 94A was centered near 7.0 degrees north latitude and 66.0 degrees east longitude, about 1,080 nautical miles south-southeast of Muscat, Oman. System 94A has fragmented bands of thunderstorms wrapping into an elongated low-level center of circulation, but it's in an environment with warm sea surface temperatures and low vertical wind shear that will allow it to develop.

In the Southern Indian Ocean, low pressure area designated System 92S was centered near 7.0 degrees south latitude and 54.2 degrees east longitude. That's about 830 nautical miles north-northeast of Antananarivo, Madagascar. The EPIC image shows that this is a large system and it appears somewhat elongated. Maximum sustained surface winds in System 92S are estimated at 25 to 30 knots (28.7 to 34.5 mph/46.3 to 55.5 kph) . Minimum sea level pressure is estimated to be near 1004 millibars.

System 94A in the Northern Indian Ocean and System 92S in the Southern Indian Ocean both have a medium chance to become a tropical depression over the next several days.

Related link:

Hurricanes: http://www.nasa.gov/mission_pages/hurricanes/main/index.html

Images (mentioned), Text, Credits: NASA's Goddard Space Flight Center/Rob Gutro.

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Seven Key Facts About Cassini's Oct. 28 'Plume Dive'

NASA - Cassini Mission to Saturn patch.

Oct. 26, 2015

NASA's Cassini spacecraft will sample the ocean of Saturn's moon Enceladus on Wednesday, Oct. 28, when it flies through the moon's plume of icy spray.

Deep Dive into Enceladus Plume

Video above: On Oct. 28, 2015, NASA's Cassini spacecraft will take the deepest dive ever through the plume of Saturn's moon Enceladus. Video Credits: NASA/JPL.

Cassini launched in 1997 and entered orbit around Saturn in 2004. Since then, it has been studying the huge planet, its rings and its magnetic field. Here are some things to know about the mission's upcoming close flyby of Enceladus:

-- Enceladus is an icy moon of Saturn. Early in its mission, Cassini discovered Enceladus has remarkable geologic activity, including a towering plume of ice, water vapor and organic molecules spraying from its south polar region. Cassini later determined the moon has a global ocean and likely hydrothermal activity, meaning it could have the ingredients needed to support simple life.

-- The flyby will be Cassini's deepest-ever dive through the Enceladus plume, which is thought to come from the ocean below. The spacecraft has flown closer to the surface of Enceladus before, but never this low directly through the active plume.

-- The flyby is not intended to detect life, but it will provide powerful new insights about how habitable the ocean environment is within Enceladus.

Image above: This artist’s rendering showing a cutaway view into the interior of Saturn’s moon Enceladus. NASA’s Cassini spacecraft discovered the moon has a global ocean and likely hydrothermal activity. A plume of ice particles, water vapor and organic molecules sprays from fractures in the moon's south polar region. Image Credits: NASA/JPL-Caltech.

-- Cassini scientists are hopeful the flyby will provide insights about how much hydrothermal activity -- that is, chemistry involving rock and hot water -- is occurring within Enceladus. This activity could have important implications for the potential habitability of the ocean for simple forms of life. The critical measurement for these questions is the detection of molecular hydrogen by the spacecraft.

-- Scientists also expect to better understand the chemistry of the plume as a result of the flyby. The low altitude of the encounter is, in part, intended to afford Cassini greater sensitivity to heavier, more massive molecules, including organics, than the spacecraft has observed during previous, higher-altitude passes through the plume.

-- The flyby will help solve the mystery of whether the plume is composed of column-like, individual jets, or sinuous, icy curtain eruptions -- or a combination of both. The answer would make clearer how material is getting to the surface from the ocean below.

-- Researchers are not sure how much icy material the plumes are actually spraying into space. The amount of activity has major implications for how long Enceladus might have been active.

An online toolkit for all three final Enceladus flybys is available at:

http://solarsystem.nasa.gov/finalflybys

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

Related article:

A Tale of Two Hemispheres: http://orbiterchspacenews.blogspot.ch/2015/10/a-tale-of-two-hemispheres.html

For more information about Cassini, visit:

http://www.nasa.gov/cassini

http://saturn.jpl.nasa.gov

http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens

Image (mentioned), Video (mentioned), Text, Credits: NASA/Dwayne Brown/Laurie Cantillo/JPL/Preston Dyches/Tony Greicius.

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A Tale of Two Hemispheres

NASA - Cassini International logo.

Oct. 26, 2015

Enceladus is a world divided. To the north, the terrain is covered in impact craters, much like other icy moons. But to the south, the record of impact cratering is much more sparse, and instead the land is covered in fractures, ropy or hummocky terrain and long, linear features.

Lit terrain seen here is on the leading side of Enceladus. North on Enceladus is up. The image was taken in visible green light with the Cassini spacecraft narrow-angle camera on July 27, 2015.

The view was obtained at a distance of approximately 70,000 miles (112,000 kilometers) from Enceladus and at a Sun-Enceladus-spacecraft, or phase, angle of 25 degrees. Image scale is 0.4 miles (0.7 kilometers) per pixel.

The Cassini mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colorado.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov or http://www.nasa.gov/cassini . The Cassini imaging team homepage is at http://ciclops.org and http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens

Image, Text,  Credits: NASA/JPL-Caltech/Space Science Institute.

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Researchers Catch Comet Lovejoy Giving Away Alcohol

L'Observatoire de Paris logo / NASA Goddard Space Flight Center logo.

Oct. 25, 2015

Comet Lovejoy lived up to its name by releasing large amounts of alcohol as well as a type of sugar into space, according to new observations by an international team. The discovery marks the first time ethyl alcohol, the same type in alcoholic beverages, has been observed in a comet. The finding adds to the evidence that comets could have been a source of the complex organic molecules necessary for the emergence of life.

Image above: Picture of the comet C/2014 Q2 (Lovejoy) on 12 February 2015 from 50km south of Paris. Image Credit: Fabrice Noel.

"We found that comet Lovejoy was releasing as much alcohol as in at least 500 bottles of wine every second during its peak activity," said Nicolas Biver of the Paris Observatory, France, lead author of a paper on the discovery published Oct. 23 in Science Advances. The team found 21 different organic molecules in gas from the comet, including ethyl alcohol and glycolaldehyde, a simple sugar.

Comets are frozen remnants from the formation of our solar system. Scientists are interested in them because they are relatively pristine and therefore hold clues to how the solar system was made. Most orbit in frigid zones far from the sun. However, occasionally, a gravitational disturbance sends a comet closer to the sun, where it heats up and releases gases, allowing scientists to determine its composition.

Image above: Picture of the comet C/2014 Q2 (Lovejoy) on 22 February 2015. Image Credit: Fabrice Noel.

Comet Lovejoy (formally cataloged as C/2014 Q2) was one of the brightest and most active comets since comet Hale-Bopp in 1997. Lovejoy passed closest to the sun on January 30, 2015, when it was releasing water at the rate of 20 tons per second. The team observed the atmosphere of the comet around this time when it was brightest and most active. They observed a microwave glow from the comet using the 30-meter (almost 100-foot) diameter radio telescope at Pico Veleta in the Sierra Nevada Mountains of Spain.

Sunlight energizes molecules in the comet's atmosphere, causing them to glow at specific microwave frequencies (if microwaves were visible, different frequencies would be perceived as different colors). Each kind of molecule glows at specific, signature frequencies, allowing the team to identify it with detectors on the telescope. The advanced equipment was capable of analyzing a wide range of frequencies simultaneously, allowing the team to determine the types and amounts of many different molecules in the comet despite a short observation period.

Some researchers think that comet impacts on ancient Earth delivered a supply of organic molecules that could have assisted the origin of life. Discovery of complex organic molecules in Lovejoy and other comets gives support to this hypothesis.

Image above: The IRAM 30-meter radio telescope. Image Credit: Nicolas Biver.

"The result definitely promotes the idea the comets carry very complex chemistry," said Stefanie Milam of NASA's Goddard Space Flight Center in Greenbelt, Maryland, a co-author on the paper. "During the Late Heavy Bombardment about 3.8 billion years ago, when many comets and asteroids were blasting into Earth and we were getting our first oceans, life didn't have to start with just simple molecules like water, carbon monoxide, and nitrogen. Instead, life had something that was much more sophisticated on a molecular level. We're finding molecules with multiple carbon atoms. So now you can see where sugars start forming, as well as more complex organics such as amino acids -- the building blocks of proteins -- or nucleobases, the building blocks of DNA. These can start forming much easier than beginning with molecules with only two or three atoms."

In July, the European Space Agency reported that the Philae lander from its Rosetta spacecraft in orbit around comet 67P/Churyumov­-Gerasimenko detected 16 organic compounds as it descended toward and then bounced across the comet's surface. According to the agency, some of the compounds detected play key roles in the creation of amino acids, nucleobases, and sugars from simpler "building-block" molecules.

Astronomers think comets preserve material from the ancient cloud of gas and dust that formed the solar system. Exploding stars (supernovae) and the winds from red giant stars near the end of their lives produce vast clouds of gas and dust. Solar systems are born when shock waves from stellar winds and other nearby supernovae compress and concentrate a cloud of ejected stellar material until dense clumps of that cloud begin to collapse under their own gravity, forming a new generation of stars and planets.

These clouds contain countless dust grains. Carbon dioxide, water, and other gases form a layer of frost on the surface of these grains, just as frost forms on car windows during cold, humid nights. Radiation in space powers chemical reactions in this frost layer to produce complex organic molecules. The icy grains become incorporated into comets and asteroids, some of which impact young planets like ancient Earth, delivering the organic molecules contained within them.

"The next step is to see if the organic material being found in comets came from the primordial cloud that formed the solar system or if it was created later on, inside the protoplanetary disk that surrounded the young sun," said Dominique Bockelée-Morvan from Paris Observatory, a co-author of the paper.

Milam was funded by a grant from the NASA Planetary Astronomy Program. The team included researchers from the Paris Observatory, CNRS (Centre National de la Recherche Scientifique, Paris), PSL Research University (Paris Sciences et Lettres, Paris), Bordeaux Observatory, France, IRAM (Institut de Radioastronomie Millimétrique, Grenoble, France) and Stockholm Observatory, Stockholm, Sweden, as well as from NASA. The 30-meter telescope used to make the team's observations is operated by IRAM, a collaboration among France, Germany, and Spain. IRAM is supported by INSU (Institut National des Sciences de l'univers)/CNRS (France), MPG (Max-Planck-Gesellschaft zur Förderung der Wissenschaften e. V.) (Germany), and IGN (Instituto Geográfico Nacional) (Spain).

Related links:

Paris Observatory, France: http://www.obspm.fr/?lang=en

NASA Goddard Space Flight Center: http://www.nasa.gov/centers/goddard/home/index.html

Images (mentioned), Text, Credits: NASA Goddard Space Flight Center/Bill Steigerwald.

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