Africa, classified

ESA - Sentinel-2 Mission logo.

3 October 2017

From the barren Sahara to lush jungles, the first high-resolution map classifying land cover types on the entire African continent has been released. The map was created using a year’s worth of data from the Sentinel-2A satellite.

At a resolution of 20 m per pixel, you can now explore African’s diverse landscapes from grasslands to croplands, water bodies to deserts.

African land cover

Land-cover mapping breaks down the different types of material on Earth’s surface. This information is important for understanding changes in land use, modelling climate change extent and impacts, conserving biodiversity and managing natural resources.

The map released this week comprises 180 000 Sentinel-2A images representing 90 terrabytes captured between December 2015 and December 2016. Considering the size of the map – about six gigabytes – a web interface was developed to visualise the data.

The map was developed under ESA’s Climate Change Initiative (CCI) Land Cover project, and users are invited to provide their feedback on the new map through an online form.

“The prototype high-resolution land cover map at 20m over Africa is an impressive demonstration of the Sentinel-2A data availability and of the present capabilities for the processing of such huge volumes of data,” said Frédéric Achard from the Joint Research Centre.

Sentinel-2

“The community dealing with land resources in Africa will surely look forward with great interest to this prototype and to its future development.”

ESA has been coordinating global land cover maps since 2002 through its GlobCover and CCI Land Cover projects at a resolution of 300 m. While the latest map of Africa is based on observations from one of the twin Sentinel-2 satellites, the launch of Sentinel-2B in March has put the possibility of a global map at 10 m within reach.

The pair of Sentinel-2 satellites offer ‘colour vision’ for Europe’s Copernicus programme. They each carry a multispectral imager with 13 spectral bands that can be used for agricultural and forestry practices and for helping manage food security. Satellite images can be used to determine various plant indices such as leaf area chlorophyll and water content.

Related links:

User feedback form: http://2016africalandcover20m.esrin.esa.int/feedback.php

Africa land cover map at 20 m: http://2016africalandcover20m.esrin.esa.int/viewer.php

Land Cover CCI: https://www.esa-landcover-cci.org/

JRC: https://ec.europa.eu/jrc/en/science-areas

Related missions:

Sentinel-2: http://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus/Sentinel-2

Images, Text, Credits: Contains modified Copernicus Sentinel data (2015-2016), processed by Land Cover CCI, ESA/ATG medialab.

Greetings, Orbiter.ch

ATLAS and CMS celebrate their 25th anniversaries

CERN - European Organization for Nuclear Research logo.

2 Oct 2017

Image above: This special ATLAS and CMS birthday cake, baked and decorated by a member of the ATLAS collaboration, Katharine Leney, represents two event displays, one from each detector, in the icing. (Image: CERN).

ATLAS and CMS are like close sisters, the best of friends and competitors all at once. Today they are both celebrating their 25th birthdays. On 1 October 1992, the two collaborations each submitted a letter of intent for the construction of a detector to be installed at the proposed Large Hadron Collider (LHC). These two documents, each around one hundred pages long, are considered the birth certificates of the two general-purpose experiments. They each contain fairly precise technical specifications, close to that of the two detectors that were eventually built, and an already long list of institutes and scientists that had joined the collaborations. The letters of intent for ALICE and LHCb, the LHC’s two other large experiments, followed a few months later.

Several months earlier, 600 physicists and engineers from 250 institutes around the world had met in Évian-les-Bains to discuss the physics and detectors of the LHC. Design proposals for various experiments were then made public. Carlo Rubbia, the Director-General of CERN at the time, proposed a schedule for selecting which experiments would go ahead, with letters of intent to be submitted for evaluation by a peer review committee. This resulted in the creation of the LHC Committee (LHCC), which began evaluating the proposals that autumn.

In June 1993, the LHCC gave the green light to the two general-purpose experiments, which then had to develop detailed technical proposals. This marked the start of a long and difficult journey that pushed the boundaries of technology and human endeavour, but which eventually led to a major discovery, that of the Higgs boson, and many other important results, the list of which keeps on growing.

- Visit the ATLAS and CMS websites to find out more about the events of the last 25 years: https://atlas.cern/atlas25 and https://cms25.web.cern.ch/

- ATLAS has been organising a series of Facebook Live events today, with a Q&A session at 6pm CEST. Visit the ATLAS Facebook page: https://www.facebook.com/ATLASexperiment/

- You can also read the ATLAS letter of intent and the CMS letter of intent:
https://cds.cern.ch/record/291061/files/cm-p00043027.pdf
https://cds.cern.ch/record/290808/files/cern-lhcc-92-003.pdf

Note:

CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 22 Member States.

Related links:

ATLAS: http://home.cern/about/experiments/atlas

CMS: http://home.cern/about/experiments/cms

ALICE: http://home.cern/about/experiments/alice

LHCb: http://home.cern/about/experiments/lhcb

Large Hadron Collider (LHC): http://home.cern/topics/large-hadron-collider

For more information about European Organization for Nuclear Research (CERN), Visit: http://home.cern/

Image (mentioned), Text, Credits: CERN/Corinne Pralavorio.

Best regards, Orbiter.ch

Hubble Is Paving Scientific Paths for NASA’s James Webb Space Telescope

NASA - Hubble Space Telescope patch.

Oct. 2, 2017

NASA’s Hubble Space Telescope is helping identify potential celestial targets for the James Webb Space Telescope through a series of preparatory science observations to be completed before Webb is ready to make observations of its own.

Image above: This image of the Westerlund 2 cluster includes both visible- and infrared-light observations from Hubble, and was released in 2015 as part of the Hubble Space Telescope's 25th anniversary. The highlighted area, featuring the cluster of stars, was created from visible-light and near-infrared exposures. The black-and-white zoomed portion shows a new image of the star cluster in only one infrared wavelength. This image was taken as part of astronomer Elena Sabbi’s preparatory science project, one of many such observations astronomers will use to identify potential targets for NASA’s James Webb Space Telescope. Image Credits: NASA, ESA, the Hubble Heritage Team (STScI/AURA), A. Nota (ESA/STScI), E. Sabbi (ESA/STScI), and the Westerlund 2 Science Team.

This preparatory science program began in 2016 in response to the desire of astronomers to use Hubble observations to set the stage for Webb. The program marked the first time astronomers were encouraged to submit science proposals for Hubble observations that could pave the way for Webb’s own observations. So far, 40 proposals have been approved.

Using multiple observatories to analyze the same objects can identify aspects of those objects that using one observatory alone cannot. Hubble was designed to primarily observe the universe through visible light (though it is also able to see into the ultraviolet and near-infrared), while Webb is specifically designed to observe the universe in infrared light, through both direct imaging and spectroscopy. Spectroscopy measures the spectrum of light, which scientists analyze to determine physical properties of what is being observed, including temperature, mass, and chemical composition.

Several preparatory science proposals in the program promise to use Hubble to deliver observational data Webb is not designed to collect. Hubble is able to see parts of the visible-light spectrum that Webb is not able to observe, and so it can fill potential observational gaps. For example, Hubble can examine exoplanets in light across the full electromagnetic spectrum available to it, with emphasis on the ultraviolet and blue wavelengths. Coupled with Webb’s infrared capabilities, both telescopes will deliver a more complete picture of the exoplanet systems.

Other proposals have a goal of using Hubble to carry some of the workload for Webb, allowing astronomers to use their observation time with Webb more efficiently. Astronomers could use Hubble to survey multiple targets and determine the best strategy for Webb to perform further analysis. Depending on the data Hubble returned, astronomers would know to observe targets with Webb in a broad range of infrared wavelengths or to focus on smaller wavelength ranges, thus giving them a better starting point for their own observations.

Hubble and Webb:  Probing protoplanetary disks

One specific preparatory science proposal was submitted by a team of scientists led by Elena Sabbi, an astronomer at the Space Telescope Science Institute in Baltimore, Maryland. Sabbi and her team are using Hubble to survey the young, massive star cluster Westerlund 2, located about 20,000 light-years from Earth in the constellation of Carina. They have spent one year observing the cluster and plan to observe it for two additional years with Hubble.

One of the primary science objectives for Webb is to observe the birth of stars and protoplanetary systems, and Sabbi’s observations promise to catalog hundreds of potential targets on which Webb could follow up. Sabbi and her team are using Hubble to look for binary stars in their earliest stages of development, where they are likely to be surrounded by protoplanetary disks — disks of dense gas and dust that encircle newly formed stars and eventually coalesce into planets.

Binary star systems contain two stars in orbit around a common central point, and some of these systems have been found to host planets. Astronomers are still trying to understand how planets form and evolve in such an environment. Sabbi said Westerlund 2’s youth makes it a prime candidate for understanding this, because as a cluster ages, binary stars often separate and are ejected from the cluster. The team’s first year of observations showed Westerlund 2 contained many more binary stars than expected, based on other observations of star clusters.

Image above: This black-and-white image of the Westerlund 2 star cluster focuses on the central part of the cluster. The image was taken by Hubble in the 800-nanometer wavelength range, in the near-infrared part of the electromagnetic spectrum just outside the range of visible light. This image was taken as part of astronomer Elena Sabbi’s preparatory science project, one goal of which is to use Hubble to identify objects of interest for NASA’s James Webb Space Telescope. Image Credits: NASA, ESA, and E. Sabbi (ESA/STScI).

“Massive clusters are very crowded places, like [New York City’s] Times Square during New Year’s Eve,” explained Sabbi. “And, just as how in Times Square the pushing and pulling of other people can separate you from your friends, the gravitational force of nearby stars can separate a star from its companion.”

The Webb telescope’s near-infrared spectrograph (NIRSpec) instrument could analyze the composition of protoplanetary disks Sabbi’s team finds around the binary stars. Armed with this data, the team could then discover how planet formation differs between single and binary star systems.

“The light that comes from these planetary systems during formation cannot be seen by Hubble,” Sabbi explained. “Hubble sees the light coming from the star, but in Webb data the light will be dominated by the planetary disk.”

The veteran space telescope

Located so close to Earth, Hubble has benefitted from multiple servicing missions to upgrade its components and science instruments, and thus its ability to survey the universe. Launched in 1990, Hubble has been orbiting Earth and observing the cosmos for 27 years — but that does not mean it’s ready for retirement.

Hubble Space Telescope. Animation Credits: NASA/ESA

“Hubble is at the peak of its scientific capability,” said Jim Jeletic, deputy project manager for the Hubble program at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. He added that the veteran space telescope “still has redundancy in all of its critical systems” and could continue its mission “well into the next decade,” meaning Hubble and Webb could work in tandem for years to come.

The James Webb Space Telescope, the scientific complement to NASA's Hubble Space Telescope, will be the most powerful space telescope ever built. Webb is an international project led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).                                                    

For more information about the Webb telescope, visit: http://www.webb.nasa.gov or http://www.nasa.gov/webb

For images and more information about Hubble, visit:

http://hubblesite.org/
http://www.nasa.gov/hubble
http://www.spacetelescope.org/

Images (mentioned), Animation (mentioned), Text, Credits: NASA/Lynn Jenner/Goddard Space Flight Center, by Eric Villard.

Best regards, Orbiter.ch

Goodbye to the Dark Side

NASA - Cassini Mission to Saturn patch.

Oct. 2, 2017

Stunning views like this image of Saturn's night side are only possible thanks to our robotic emissaries like Cassini. Until future missions are sent to Saturn, Cassini's image-rich legacy must suffice.

Because Earth is closer to the Sun than Saturn, observers on Earth only see Saturn’s day side. With spacecraft, we can capture views (and data) that are simply not possible from Earth, even with the largest telescopes.

This view looks toward the sunlit side of the rings from about 7 degrees above the ring plane. The image was taken in visible light with the wide-angle camera on NASA's Cassini spacecraft on June 7, 2017.

The view was obtained at a distance of approximately 751,000 miles (1.21 million kilometers) from Saturn. Image scale is 45 miles (72 kilometers) per pixel.

The Cassini spacecraft ended its mission on Sept. 15, 2017.

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 https://saturn.jpl.nasa.gov and https://www.nasa.gov/cassini. The Cassini imaging team homepage is at http://ciclops.org and ESA's website: http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens

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

Greetings, Orbiter.ch

ALMA and Rosetta Detect Freon-40 in Space

ALMA - Atacama Large Millimeter/submillimeter Array logo / ESA - Rosetta Mission patch.

2 October 2017

Dashing Hopes that Molecule May be Marker of Life

ALMA and Rosetta Detect Freon-40 in Space

Observations made with the Atacama Large Millimeter/submillimeter Array (ALMA) and ESA’s Rosetta mission, have revealed the presence of the organohalogen Freon-40 in gas around both an infant star and a comet. Organohalogens are formed by organic processes on Earth, but this is the first ever detection of them in interstellar space. This discovery suggests that organohalogens may not be as good markers of life as had been hoped, but that they may be significant components of the material from which planets form. This result, which appears in the journal Nature Astronomy, underscores the challenge of finding molecules that could indicate the presence of life beyond Earth.

ROSINA on Rosetta finds Freon-40 at Comet 67P/Churyumov–Gerasimenko

Using data captured by ALMA in Chile and from the ROSINA instrument on ESA’s Rosetta mission, a team of astronomers has found faint traces of the chemical compound Freon-40 (CH3Cl), also known as methyl chloride and chloromethane, around both the infant star system IRAS 16293-2422 [1], about 400 light-years away, and the famous comet 67P/Churyumov-Gerasimenko (67P/C-G) in our own Solar System. The new ALMA observation is the first detection ever of a stable organohalogen in interstellar space [2].

IRAS 16293-2422 in the constellation of Ophiuchus

Organohalogens consist of halogens, such as chlorine and fluorine, bonded with carbon and sometimes other elements. On Earth, these compounds are created by some biological processes — in organisms ranging from humans to fungi —  as well as by industrial processes such as the production of dyes and medical drugs [3].

This new discovery of one of these compounds, Freon-40, in places that must predate the origin of life, can be seen as a disappointment, as earlier research had suggested that these molecules could indicate the presence of life.

The Rho Ophiuchi star formation region in the constellation of Ophiuchus

“Finding the organohalogen Freon-40 near these young, Sun-like stars was surprising,” said Edith Fayolle, a researcher with the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts in the USA, and lead author of the new paper. “We simply didn't predict its formation and were surprised to find it in such significant concentrations. It’s clear now that these molecules form readily in stellar nurseries, providing insights into the chemical evolution of planetary systems, including our own.”

Exoplanet research has gone beyond the point of finding planets — more than 3000 exoplanets are now known — to looking for chemical markers that might indicate the potential presence of life. A vital step is determining which molecules could indicate life, but establishing reliable markers remains a tricky process.

ALMA and Rosetta Detect Freon-40 in Space

“ALMA’s discovery of organohalogens in the interstellar medium also tells us something about the starting conditions for organic chemistry on planets. Such chemistry is an important step toward the origins of life,” adds Karin Öberg, a co-author on the study. “Based on our discovery, organohalogens are likely to be a constituent of the so-called ‘primordial soup’, both on the young Earth and on nascent rocky exoplanets.”

This suggests that astronomers may have had things around the wrong way; rather than indicating the presence of existing life, organohalogens may be an important element in the little-understood chemistry involved in the origin of life.

Co-author Jes Jørgensen from the Niels Bohr Institute at University of Copenhagen adds: "This result shows the power of ALMA to detect molecules of astrobiological interest toward young stars on scales where planets may be forming. Using ALMA we have previously found precursors to sugars and amino acids around different stars. The additional discovery of Freon-40 around Comet 67P/C-G strengthens the links between the pre-biological chemistry of distant protostars and our own Solar System."

Zooming in on the Rho Ophiuchi star formation region

The astronomers also compared the relative amounts of Freon-40 that contain different isotopes of chlorine in the infant star system and the comet — and found similar abundances. This supports the idea that a young planetary system can inherit the chemical composition of its parent star-forming cloud and opens up the possibility that organohalogens could arrive on planets in young systems during planet formation or via comet impacts.

“Our results shows that we still have more to learn about the formation of organohalogens,” concludes Fayolle. “Additional searches for organohalogens around other protostars and comets need to be undertaken to help find the answer.”

Notes:

[1] This protostar is a binary star system surrounded by a molecular cloud in the Rho Ophiuchi star-forming region, which makes it an excellent target for ALMA’s millimetre/submillimetre view.

[2] The data used were from the ALMA Protostellar Interferometric Line Survey (PILS). The aim of this survey is to chart the chemical complexity of IRAS 16293-2422 by imaging the full wavelength range covered by ALMA in the 0.8-millimetre atmospheric window on very small scales, equivalent to the size of the Solar System.

The species CF+, which could be considered as an organohalogen, had already been detected, but is not stable.

[3] Freons were widely used as a refrigerants (hence the name) but are now banned as they have a destructive effect on the Earth’s protective ozone layer.

More information:

This research was presented in a paper “Protostellar and Cometary Detections of Organohalogens” by E. Fayolle et al., to appear in Nature Astronomy on 2 October 2017.

The team is composed of Edith C. Fayolle (Harvard-Smithsonian Center for Astrophysics, USA), Karin I. Öberg (Harvard-Smithsonian Center for Astrophysics, USA),  Jes K. Jørgensen (University of Copenhagen, Denmark), Kathrin Altwegg (University of Bern, Switzerland),  Hannah Calcutt (University of Copenhagen, Denmark), Holger S. P. Müller (Universität zu Köln, Germany), Martin Rubin (University of Bern, Switzerland), Matthijs H. D. van der Wiel (The Netherlands Institute for Radio Astronomy, The Netherlands), Per Bjerkeli (Onsala Space Observatory, Sweden), Tyler L. Bourke (Jodrell Bank Observatory, UK), Audrey Coutens (University College London, UK), Ewine F. van Dishoeck (Leiden University, The Netherlands; Max-Planck-Institut für extraterrestrische Physik, Germany), Maria N. Drozdovskaya (University of Bern, Switzerland), Robin T. Garrod (University of Virginia, USA), Niels F. W. Ligterink (Leiden University, The Netherlands), Magnus V. Persson (Onsala Space Observatory, Sweden), Susanne F. Wampfler (University of Bern, Switzerland) and the ROSINA team.

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).

ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope and its world-leading Very Large Telescope Interferometer as well as two survey telescopes, VISTA working in the infrared and the visible-light VLT Survey Telescope. ESO is also a major partner in two facilities on Chajnantor, APEX and ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre Extremely Large Telescope, the ELT, which will become “the world’s biggest eye on the sky”.

Links:

ESOcast 131 Light: ALMA and Rosetta Detect Freon-40 in Space: http://www.eso.org/public/videos/eso1732a/

Research paper in Nature Astronomy: https://www.eso.org/public/archives/releases/sciencepapers/eso1732/eso1732a.pdf

Earlier results on this star from ALMA: methyl isocyanate and sugars:
http://eso.org/public/news/eso1718/
http://eso.org/public/news/eso1234/

Photos of ALMA: http://www.eso.org/public/images/archive/category/alma/

Atacama Large Millimeter/submillimeter Array (ALMA): http://www.eso.org/public/teles-instr/alma/

ALMA Protostellar Interferometric Line Survey (PILS): https://www.aanda.org/articles/aa/pdf/forth/aa28648-16.pdf

ESA’s Rosetta: http://www.esa.int/Our_Activities/Space_Science/Rosetta

ROSINA instrument: http://sci.esa.int/rosetta/35061-instruments/?fbodylongid=1650

Images, Text, Credits: ESO/Richard Hook/Leiden Observatory/Ewine van Dishoeck/Niels Bohr Institute, University of Copenhagen/Jes K. Jørgensen/Harvard-Smithsonian Center for Astrophysics/Edith Fayolle/B. Saxton (NRAO/AUI/NSF); NASA/JPL-Caltech/UCLA/IAU and Sky & Telescope/Digitized Sky Survey 2/Acknowledgement: Davide De Martin/Video: ESO, S. Guisard (www.eso.org/~sguisard), N. Risinger (skysurvey.org). Music: Johan B. Monell (www.johanmonell.com).

Best regards, Orbiter.ch

Catching the Shadow of a Neptunian Moon

NASA & DLR - SOFIA Boeing 747P patch.

October 1, 2017

Flying observatory SOFIA. Image Credit: NASA

Researchers on the flying observatory SOFIA, the Stratospheric Observatory for Infrared Astronomy, are preparing for a two-minute opportunity to study the atmosphere of Neptune’s moon Triton as it casts a faint shadow on Earth’s surface. This is the first chance to investigate Triton’s atmosphere in 16 years.

On Oct. 5, as Triton passes in front of a faraway star it will block the star’s light in an eclipse-like event called an occultation. During the celestial alignment, the team aboard the specially equipped Boeing 747SP aircraft will make observations of the distant star’s light as it passes through Triton’s atmosphere.

Animation above: Artist's concept of an occultation illustrating Triton passing in front of a distant star. Catching the Shadow of a Neptunian Moon. Animation credit: NASA.

Triton has not passed in front of bright stars for many years, making occultation observations difficult. Now, as Triton passes in front of a bright star, the data collected by SOFIA’s 100-inch (2.5-meter) on board telescope and three powerful instruments will enable researchers to better study and characterize the moon’s atmosphere, including its temperature, pressure and density.

Previous observations, including those from NASA’s Voyager 2 spacecraft taken in 1989 and a previous occultation observation in 2001, indicate that Triton’s atmosphere is made mostly of nitrogen and is distorted at different locations by its high winds and strong tides. These new occultation data may also provide details about how the atmosphere varies at different altitudes, enabling researchers to examine if the atmosphere has changed since it was last studied.

Catching a Shadow

Catching Triton’s shadow as it races across Earth’s surface at more than 37,000 mph (17 km/s) while the aircraft is traveling at Mach 0.85 (approximately 652 mph), is no small feat. To ensure that they are in the right place at the right time, researchers have made advanced observations of Triton and the star with multiple telescopes to determine the location of their shadow. From these precise calculations, SOFIA’s flight planners have designed a flight plan that will put the flying observatory in the center of the shadow for approximately two minutes as Triton aligns in front of the star.

Animation above: SOFIA · Artist's concept of SOFIA flying into the shadow of celestial bodies. Animation Credit: NASA.

“SOFIA is the only observatory able to position itself directly in the shadow’s centerline while avoiding any obscuring clouds,” said Ted Dunham, astronomer from the Lowell Observatory in Arizona and instrument scientist for the High Speed Photometer for Occultations (HIPO). “With the dedicated SOFIA team and three onboard instruments, we can make the precise measurements necessary to study Triton’s atmosphere in great detail.”

Though challenging, SOFIA’s team has previously used this method to make successful observations of Pluto’s atmosphere with SOFIA in 2011 and 2015. Additionally, researchers on SOFIA’s predecessor, the Kuiper Airborne Observatory, discovered Uranus’ rings while studying an occultation by that planet in 1977.

Ground and Air Observations Take Shape

Triton has strong tides because it is close to Neptune, much closer than our moon is to Earth. These powerful tides combined with its strong winds, change the shape of its atmosphere. To measure the overall shape of Triton’s atmosphere, the researchers are also teaming with more than 30 ground-based telescopes across the Eastern United States and Europe. Most of these telescopes are not located where the center of the shadow will fall, but they will make simultaneous observations of different areas of Triton’s atmosphere to get a global view of its shape. The data from across Earth, combined with that collected onboard SOFIA, will help researchers understand how these forces influence the atmosphere.

“The ground-based campaign augments both the visible and infrared data from SOFIA, to give us a global perspective of Triton's atmosphere,” Kimberly Ennico Smith, SOFIA project scientist at NASA’s Ames Research Center in California’s Silicon Valley.

Image above: The borders of Triton's shadow across Earth's surface are indicated by black lines on this map, while the orange line is the path of the shadow's center. SOFIA’s flight path is represented by the red line; the point of the crucial, two-minute observation of Triton as it aligns with the star is marked by the airplane. The red and blue dots represent the ground-based telescopes that will also observe Triton. Image Credits: DSI/ Karsten Schindler (Map data, Google).

The center of Triton’s shadow, which is predicted to fall over the Eastern United States, the Atlantic Ocean, and Europe, is far from SOFIA’s home base at NASA’s Armstrong Flight Research Center in Palmdale, California. For this flight, the flying observatory will operate from a temporary base in Daytona Beach, Florida, to complete these observations. From Florida, SOFIA can reach the shadow’s center and return during a single, nine-hour observing flight.

Follow along on social media with https://twitter.com/SOFIAtelescope and #NeptunesMoon as SOFIA chases Triton’s shadow, and join the mission crew live with NASA on Snapchat on Oct. 5: https://www.snapchat.com/add/nasa

SOFIA is a joint project of NASA and the German Aerospace Center, DLR. NASA’s Ames Research Center manages the SOFIA program, science and mission operations in cooperation with the Universities Space Research Association headquartered in Columbia, Maryland, and the German SOFIA Institute (DSI) at the University of Stuttgart. The aircraft is based at NASA’s Armstrong Flight Research Center's Hangar 703, in Palmdale, California.

For more information about SOFIA visit:

http://www.nasa.gov/sofia • http://www.dlr.de/en/sofia

For more information about SOFIA’s science misson and scientific instruments visit: http://www.sofia.usra.edu • http://www.dsi.uni-stuttgart.de/index.en.html

Related link:

NASA’s Voyager 2 spacecraft: https://www.jpl.nasa.gov/missions/voyager-2/

Images (mentioned, Animations (mentioned), Text, Credits: NASA Ames Research Center/Kassandra Bell/Nicholas A. Veronico.

Best regards, Orbiter.ch

Pinpointing Where the Lights Went Out in Puerto Rico

NASA - Suomi NPP Mission logo.

October 1, 2017

After Hurricane Maria tore across Puerto Rico, it quickly became clear that the destruction would pose daunting challenges for first responders. Most of the electric power grid and telecommunications network was knocked offline. Flooding, downed trees, and toppled power lines made many roads impassable.

In circumstances like this, quickly knowing where the power is out—and how long it has been out—allows first responders to better deploy rescue and repair crews and to distribute life-saving supplies. And that is exactly why teams of scientists at NASA are working long days to make sure that groups like the National Guard and the Federal Emergency Management Agency (FEMA) get high-quality satellite maps of power outages in Puerto Rico.

These before-and-after images of Puerto Rico’s nighttime lights are based on data captured by the Suomi NPP satellite. The data was acquired by the Visible Infrared Imaging Radiometer Suite (VIIRS) “day-night band,” which detects light in a range of wavelengths from green to near-infrared, including reflected moonlight, light from fires and oil wells, lightning, and emissions from cities or other human activity.

The images above show lighting around San Juan, capital of the commonwealth; the images below show the entire island. One image in each pair shows a typical night before Maria made landfall, based upon cloud-free and low moonlight conditions; the second image is a composite that shows light detected by VIIRS on the nights of September 27 and 28, 2017. By compositing two nights, the image has fewer clouds blocking the view. (Note: some clouds still blocked light emissions during the two nights, especially across southeastern and western Puerto Rico.) The images above show widespread outages around San Juan, including key hospital and transportation infrastructure.

Note that these maps are not showing raw imagery of light. A team of scientists from NASA’s Goddard Space Flight Center and Marshall Space Flight Center processed and corrected the raw data to filter out stray light from the Moon, fires, airglow, and any other sources that are not electric lights. Their processing techniques also remove as much other atmospheric interference—such as dust, haze, and thin clouds—as possible.

To make the VIIRS data more useful to first responders, the Goddard team scaled the observations onto a base map that emphasizes the locations of streets and neighborhoods. The base map makes use of data collected by the Landsat, Sentinel-2, TanDEM-X, and TerraSAR-X satellites. It also incorporates high-resolution data from OpenStreetMap to show the precise locations of streets and neighborhoods.

“It is critical that we get this processing done quickly, so that we can provide the cleanest and most useful imagery to the National Guard, FEMA, and other first responders,” said Miguel Román, who is leading the effort from Goddard. “Uncorrected images can be misleading because of things like cloud cover and changing moonlight conditions.”

Román’s team is also working closely with colleagues from the Short-term Prediction Research and Transition Center (SPoRT) at NASA Marshall, as well as NASA’s Earth Science Disasters Program, to develop and share data products with first responders.

Artist's rendition of Suomi NPP satellite

“The expertise of the SPoRT team focuses on helping end users make effective decisions from innovative NASA, NOAA, and partner data products,” said Andrew Molthan, co-investigator of the SPoRT Center. “It has been rewarding to work with Goddard colleagues on solutions that can assist with response efforts.”

Jordan Bell of the SPoRT team, for instance, has developed a product in conjunction with Esri that will display corrected and updated VIIRS observations of nighttime lights on a daily basis and include cloud mapping as detected by NOAA’s VIIRS cloud detection algorithms.

Note that these high-definition black marble maps are experimental. They are designed to make it easier to monitor neighborhood-scale outdoor features; they should not be used to monitor power outages in individual buildings or roads.

These interactive maps can be viewed here:
https://www.arcgis.com/apps/MapSeries/index.html?appid=6135434f7ffe4b13b815afc6dd052eb3

References and Further Reading:

- Cole, et al. (2017) Synergistic Use of Nighttime Satellite Data, Electric Utility Infrastructure, and Ambient Population to Improve Power Outage Detections in Urban Areas. Remote Sensing, 9 (3), 286. http://dx.doi.org/10.3390/rs9030286

- Molthan, A. & Jedlovec, G. (2013) Satellite Observations Monitor Outages From Superstorm Sandy. EOS, 94 (5), 53-54. http://www.dx.doi.org/10.1002/2013EO050001

- NASA Earth Observatory (2017, April 12) Black Marble 2017: Night Light Maps Open Up New Applications. https://earthobservatory.nasa.gov/Features/NightLights/

- NASA Earth Observatory (2017) Hurricane Marie 2017. https://earthobservatory.nasa.gov/NaturalHazards/event.php?id=91003

- The Boston Globe (2017, September 25) Damage to Puerto Rico’s power grid is unprecedented. Accessed September 28, 2017. https://www.bostonglobe.com/news/nation/2017/09/25/damage-puerto-rico-power-grid-unprecedented/8XnniwOHxWKqs2WYz5J8gM/story.html

- U.S. Energy Information Administration (2017, September 21) Puerto Rico. Accessed September 28, 2017. https://www.eia.gov/state/analysis.php?sid=RQ

- Vox (2017, September 6) Why Puerto Rico’s power outages could prove very deadly, in one chart. Accessed September 28, 2017. https://www.vox.com/science-and-health/2017/9/25/16361050/puerto-rico-power-outages-deadly

- Wired (2017, September 27) After Hurricane Maria, Puerto Rico’s Grid Needs a Complete Overhaul. Accessed September 28, 2017. https://www.wired.com/story/after-hurricane-maria-puerto-ricos-grid-needs-a-complete-overhaul/

Related links:

Suomi NPP satellite: https://www.nasa.gov/mission_pages/NPP/mission_overview/index.html

Visible Infrared Imaging Radiometer Suite (VIIRS): https://jointmission.gsfc.nasa.gov/viirs.html

OpenStreetMap: https://www.openstreetmap.org/about

Short-term Prediction Research and Transition Center (SPoRT): https://weather.msfc.nasa.gov/sport/

NASA’s Earth Science Disasters Program: https://disasters.nasa.gov/

Images, Text, Credits: NASA Earth Observatory images by Joshua Stevens, using data courtesy of Miguel Román, NASA GSFC, and Andrew Molthan, NASA MSFC. Story by Adam Voiland.

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