samedi 25 mars 2017

CryoSat reveals Antarctica in 3D







ESA - CRYOSAT Mission logo.

25 March 2017

Around 250 million measurements taken by ESA’s CryoSat over the last six years have been used to create a unique 3D view of Antarctica, offering a snapshot of the undulating surface of this vast ice sheet.

Antarctica in 3D

CryoSat’s radar altimeter detects tiny variations in the height of the ice across the entire continent, including on the steeper continental margins where the vast majority of ice losses occur.

Importantly, the satellite’s orbit takes it to latitudes within 200 km of the north and south poles – closer than other Earth observation satellites.

Naturally, the mission is also used to map changes in the thickness of ice floating in the polar oceans, which is particularly important for the Arctic.

This new ‘digital elevation model’ was revealed at this week’s gathering of CryoSat scientists in Banff, Canada.

Tom Slater, researcher at the UK Centre for Polar Observation and Modelling (CPOM), said, “We used around 250 million measurements taken by CryoSat between 2010 and 2016 to create the most comprehensive picture of Antarctic ice elevation currently available.”

It offers wide range of applications – showing the surface of Antarctica in such detail means it can be used in anything from planning fieldwork to modelling the ice sheet. 

Ice height

It also allows scientists to distinguish between changes in topography and ice motion when working with other satellite measurements, such as those used to calculate the balance between how much the ice sheet is gaining by accumulating snow and losing through melting and creating icebergs.

The model will soon be freely available via the CPOM portal, which already provides information on sea-ice volume and thickness, ice velocity and, shortly, ice sheets. In the meantime, however, the model can be downloaded here: https://www.dropbox.com/sh/qpve6qcxyi2xi48/AADlIY4ClO1r8y4oRnVJFekga?dl=0

CPOM Director Andrew Shepherd added, “We want the digital elevation model to be accessible to anyone who uses ice-sheet surface topography measurements in their work.

“This should benefit not only studies of the Antarctic ice sheet, but also projections of future sea-level rise.”

ESA's ice mission

ESA’s CryoSat mission manager, Tommaso Parrinello, said, “We are hearing some great results from our mission at the meeting here in Banff.

“It’s now widely recognised that dwindling polar ice is one of the first casualties of climate change, but it’s important to provide the hard facts – and this we can do with CryoSat.

“It’s equally important to make sure the satellite’s data are correct and so we have a huge international field campaign just started in the Arctic to take ‘ground  truth’ measurements from aircraft and on the ice to compare with those of CryoSat. It’s a tough environment – so we wish them lots of luck.”

Related links:

Antarctica digital elevation model: https://www.dropbox.com/sh/qpve6qcxyi2xi48/AADlIY4ClO1r8y4oRnVJFekga?dl=0

CryoSat: http://www.esa.int/Our_Activities/Observing_the_Earth/CryoSat

Access CryoSat data: https://earth.esa.int/web/guest/missions/esa-operational-eo-missions/cryosat

CryoSat Science Meeting: http://cryosat2017.org/

Centre for Polar Observation and Modelling: http://cpom.org.uk/

CPOM data portal: http://www.cpom.ucl.ac.uk/csopr/index.html

Natural Environment Research Council: https://www.nceo.ac.uk/

Images, Text, Credits: ESA/CPOM/AOES Medialab.

Best regards, Orbiter.ch

vendredi 24 mars 2017

Weekly Recap From the Expedition Lead Scientist, week of March 13, 2017











ISS - Expedition 50 Mission patch.

March 24, 2017

(Highlights: Week of March 13, 2017) - Crew members on the International Space Station worked on a pair of investigations into water that could result in cleaner water on Earth.


Image above: This long-exposure image captures a pair of Russian Soyuz capsules attached to the International Space Station as the outpost flies over the night lights of Earth at 17,500 mph. Image Credit: NASA.

ESA (European Space Agency) astronaut Thomas Pesquet sampled filtered water on the space station as part of the Water Monitoring Suite experiment. This new technology can quickly detect and identify potentially harmful microorganisms in the station's water supply. If successful, it will ensure that crew members can perform real time tests and monitor the safety of their water on future missions.

Using current technology, it can take a week to search for harmful bacteria. With the Water Monitoring Suite – part of the Microbial Monitoring System on the station – it could take less than an hour. This would be invaluable to travelers in space where water is a very limited and precious commodity, and could also help millions of people on Earth who do not have access to clean water. Equipment that is fast and simple to use can improve water quality monitoring in remote areas.


Image above: NASA astronaut Shane Kimbrough loads organic samples into the Minus Eighty Degree Laboratory Freezer for ISS (MEFLI) in preparation of sending them back to Earth on the SpaceX 10 Dragon capsule. Image Credit: NASA.

Pesquet worked on a separate investigation into clean water on the station, injecting water into a pair of Aquapads and leaving them to incubate at ambient temperature inside the orbiting laboratory. After two days, he took photographs of the resulting bacterial contamination in the cotton-based petri dish.

The water astronauts drink on the station is recycled by up to 80 percent from their sweat, urine, and other reclaimed wastewater sources. Recycling water reduces the number of supply missions needed to run the station, and building a self-sufficient spacecraft is necessary for future missions traveling farther from our planet. Using a device that consists of a simple absorbent cotton -- injected with 1 milliliter of water -- and a tablet computer application, ESA’s Aquapad aims to improve the speed and efficiency of water tests in orbit. This quick and simple analysis of water could also help test drinking water on Earth in countries where access to safe water to drink is a constant problem. Aquapad could also be used to diagnose the state of the water after natural disasters.

Pesquet packed samples of the study of gravity-controlled growth and development in plants using true microgravity conditions (Auxin Transport) for delivery back to Earth on the SpaceX 10 Dragon capsule. The JAXA (Japan Aerospace Exploration Agency) investigation seeks new insight into how gravity – or the lack of it – affects plant development. The study focuses on auxins – a plant hormone discovered by observing how plants respond to light.


Image above: ESA astronaut Thomas Pesquet initiated the ESA-sponsored Aquapad technology demonstration and sampling using the Microbial Monitoring System (MMS) portion of the Water Monitoring Suite (WMS) experiment. Image Credit: NASA.

Scientists will study the role auxins play in pea and corn seedlings grown in microgravity. Future space travelers will require plant and oxygen production during long space missions and scientists need to understand how to grow plants in microgravity, where there is no clear distinction between up and down. This investigation develops new techniques for controlling plant growth direction by using plant hormones, including auxins, involved in plant development. Results may provide new techniques for efficiently growing and watering seedlings in microgravity, benefiting future life sciences investigations as well as plant cultivation in space. This research can also provide additional insight on how to utilize plants to provide more suitable and comfortable environmental conditions on Earth.

Human research investigations conducted this week include At Home in Space, Fine Motor Skills, Energy, Habitability, Space Headaches, and Dose Tracker.

Progress was made on other investigations, outreach activities, and facilities this week, including APEX-4, CASIS PCG 5, Tangolab-1, Simple Solar Neutron Detector, Google Street View, Meteor, Tropical Cyclone, Microgravity Expanded Stem Cells, Rodent Research-4, ISS Ham Radio, Group Combustion, SODI-DCMIX #3, Multi-Gas Monitor, MAGVECTOR, BEAM, Radi-N2, Manufacturing Device, ExHAM #2 and NanoRacks Science Box, NanoRacks Modules 9 & 71.

Related links:

Water Monitoring Suite: http://www.nasa.gov/mission_pages/station/research/experiments/2109.html

Aquapads: https://www.nasa.gov/mission_pages/station/research/experiments/2357.html

Auxin Transport: http://www.nasa.gov/mission_pages/station/research/experiments/1991.html

At Home in Space: https://www.nasa.gov/mission_pages/station/research/experiments/1988.html

Fine Motor Skills: https://www.nasa.gov/mission_pages/station/research/experiments/1767.html

Energy: https://www.nasa.gov/mission_pages/station/research/experiments/397.html

Habitability: https://www.nasa.gov/mission_pages/station/research/experiments/1772.html

Space Headaches: https://www.nasa.gov/mission_pages/station/research/experiments/181.html

Dose Tracker: http://www.nasa.gov/mission_pages/station/research/experiments/1933.html

APEX-4: https://www.nasa.gov/mission_pages/station/research/experiments/1762.html

CASIS PCG 5: https://www.nasa.gov/mission_pages/station/research/experiments/1972.html

Meteor: https://www.nasa.gov/mission_pages/station/research/experiments/1323.html

Tropical Cyclone: https://www.nasa.gov/mission_pages/station/research/experiments/1973.html

Microgravity Expanded Stem Cells: https://www.nasa.gov/mission_pages/station/research/experiments/1971.html

Rodent Research-4: https://www.nasa.gov/mission_pages/station/research/experiments/2025.html

ISS Ham Radio: http://www.nasa.gov/mission_pages/station/research/experiments/346.html

Group Combustion: https://www.nasa.gov/mission_pages/station/research/experiments/1077.html

SODI-DCMIX #3: https://www.nasa.gov/mission_pages/station/research/experiments/1175.html

Multi-Gas Monitor: https://www.nasa.gov/mission_pages/station/research/experiments/1187.html

MAGVECTOR: https://www.nasa.gov/mission_pages/station/research/experiments/1176.html

BEAM: https://www.nasa.gov/mission_pages/station/research/experiments/1804.html

Radi-N2: https://www.nasa.gov/mission_pages/station/research/experiments/898.html

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Text, Credits: NASA/Kristine Rainey/Jorge Sotomayor, Lead Increment Scientist Expeditions 49 & 50.

Best regards, Orbiter.ch

Extending Science in the Search for the Origin of the Cosmos












ISS - AMS-02 Mission patch.

March 24, 2017

Attached to the outside of the International Space Station, the Alpha Magnetic Spectrometer (AMS) is circling Earth and sifting through cosmic ray particles traveling in the universe. Hundreds of scientists from 16 countries are analyzing the data, hoping to determine what the universe is made of and how it began, looking for clues on the origin of dark matter, invisible matter that can't be directly detected but can be inferred, and the existence of antimatter, made of elementary particles with the opposite charge of ordinary matter, which scientists have rarely been able to observe.

AMS is composed of a magnet and several detectors that provide the scientists on the ground with information about the particles. The magnetic field produced by the magnet bends the trajectory of the electrically-charged cosmic ray particles already traveling in the space station’s path, thereby identifying the sign of the particle’s charge. AMS records the number of particles that pass through its detectors; the kinds of particles passing, characteristics such as particle charge, the sign of the charge (positive or negative), mass and velocity; and which direction they came from so that scientists can attempt to track down their source. All of the information is collected using 300,000 data channels in the nanoseconds it takes a particle to travel through AMS, and then sent down to scientists on the ground for analysis.

The more particles AMS is able collect, the more scientists will be able to strengthen their findings. Launched in 2011, AMS was originally designed to operate for the duration of a three year mission, and has already surpassed that expectation. With the extension of the station through 2024, engineers are currently assessing long-term plans to extend the life of AMS to collect data throughout the lifetime of the station.

 Alpha Magnetic Spectrometer (AMS) on International Space Station (ISS)

Having exceeded the original three-year lifespan, some components are beginning to show wear. In particular, the thermal control system for one of the detectors, called the Silicon Tracker, has shown degradation. The system includes four redundant cooling pumps, only one of which is required to operate at given time. One of the pumps stopped functioning in March 2014, and another pump was found to have degraded as well, leading engineers on the ground to switch to one of two remaining pumps by the end of 2014 to continue collecting science data. A thermal cover was added during a spacewalk in 2015, and engineers switched to the last fully functional pump in March 2017 after the third pump showed similar signs of degradation.

A functioning thermal control system is required to support the silicon tracker, and data from the silicon tracker is needed in combination with the data from the other trackers to support the AMS research. The other components of AMS appear to be in good shape, and long-term planning is underway to evaluate the potential to bypass the pumps and associated equipment for this tracker with an upgraded system put in place during a series of spacewalks.

Close to 100 billion cosmic rays with energies up to multi trillion electron volts have been analyzed by AMS. Results to date have already challenged our understanding of the origin of cosmic ray particles and how they travel through the universe. For example, researchers have found an excess of high-energy positron particles, which are the anti-particle opposite to the common electron. The excess of positrons might be from a source we are familiar with, such as a pulsar, but they could also be produced by collisions of particles of dark matter. With additional data, enabled by extending the life of AMS, scientist may be able to determine the rate at which they decrease, shedding light on a possible cause. To provide further insight, AMS scientists are also analyzing high-energy antiprotons, which pulsars do not produce and may be a unique signature of dark matter.

AMS is a joint effort between NASA and the Department of Energy’s Office of Science and is led by Principal Investigator Samuel Ting, a Nobel laureate from the Massachusetts Institute of Technology.  The AMS team includes some 600 physicists from 56 institutions in 16 countries from Europe, North America and Asia. The contributions from the various participants were integrated when the AMS was built at the European Organization for Nuclear Research (CERN) outside of Geneva, Switzerland.

Alpha Magnetic Spectrometer (AMS): https://ams.nasa.gov/

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

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

Image (mentioned), Text, Credits: NASA/Kathryn Hambleton.

Greetings, Orbiter.ch

Spacewalkers Successfully Complete Primary Tasks













ISS - Expedition 50 Mission patch / EVA - Extra Vehicular Activities patch.

March 24, 2017

Expedition 50 Commander Shane Kimbrough of NASA and Flight Engineer Thomas Pesquet of ESA (European Space Agency concluded their spacewalk at 1:58 p.m. EDT. During the spacewalk, which lasted just over six-and-a-half hours, the two astronauts successfully disconnected cables and electrical connections on the Pressurized Mating Adapter-3 to prepare for its robotic move Sunday, March 26.

The PMA-3 provides the pressurized interface between the station modules and the International Docking Adapter, which will accommodate commercial crew vehicle dockings.


Image above: Spacewalkers Thomas Pesquet (left) and Shane Kimbrough meet at the Quest airlock to begin wrapping up their successful spacewalk. Image Credit: NASA TV.

The astronauts also lubricated the latching end effector on the Special Purpose Dexterous Manipulator “extension” for the Canadarm2 robotic arm, inspected a radiator valve and replaced cameras on the Japanese segment of the outpost.

A second spacewalk has been rescheduled to Thursday, March 30, and a third spacewalk now is targeted for Thursday, April 6.

The second spacewalk will feature Kimbrough and Flight Engineer Peggy Whitson of NASA reconnecting cables and electrical connections on PMA-3 at its new home on top Harmony. They also will install the second of the two upgraded computer relay boxes on the station’s truss and install shields and covers on PMA-3 and the now-vacant common berthing mechanism port on Tranquility.

video
Space Station Crew Members Walk in Space with an Eye to the Future

The plan for the final spacewalk is for Whitson and Pesquet to replace an avionics box on the starboard truss called an ExPRESS Logistics Carrier, a storage platform. The box houses electrical and command and data routing equipment for the science experiments and replacement hardware stored outside of the station. The new avionics box is scheduled to launch on the upcoming Orbital ATK Cygnus cargo spacecraft mission.

Spacewalkers have now spent a total of 1,236 hours and 38 minutes working outside the station during 198 spacewalks in support of assembly and maintenance of the orbiting laboratory.

Related links:

International Docking Adapter: https://www.nasa.gov/feature/meet-the-international-docking-adapter

Canadarm2: https://www.nasa.gov/audience/foreducators/k-4/features/F_Canadian_Crane.html

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Image (mentioned), Video (NASA TV), Text, Credits: NASA/Mark Garcia.

Best regards, Orbiter.ch

NASA’s Juno Spacecraft Set for Fifth Jupiter Flyby












NASA - JUNO Mission logo.

March 24, 2017


Image above: This enhanced-color image of a mysterious dark spot on Jupiter seems to reveal a Jovian “galaxy” of swirling storms. Image Credits: NASA/JPL-Caltech/SwRI/MSSS/Roman Tkachenko.

NASA's Juno spacecraft will make its fifth flyby over Jupiter's mysterious cloud tops on Monday, March 27, at 1:52 a.m. PDT (4:52 a.m. EDT, 8:52 UTC).

At the time of closest approach (called perijove), Juno will be about 2,700 miles (4,400 kilometers) above the planet's cloud tops, traveling at a speed of about 129,000 miles per hour (57.8 kilometers per second) relative to the gas-giant planet. All of Juno's eight science instruments will be on and collecting data during the flyby.

"This will be our fourth science pass -- the fifth close flyby of Jupiter of the mission -- and we are excited to see what new discoveries Juno will reveal,” said Scott Bolton, principal investigator of Juno from the Southwest Research Institute in San Antonio. "Every time we get near Jupiter’s cloud tops, we learn new insights that help us understand this amazing giant planet."

The Juno science team continues to analyze returns from previous flybys. Scientists have discovered that Jupiter's magnetic fields are more complicated than originally thought, and that the belts and zones that give the planet's cloud tops their distinctive look extend deep into the its interior. Observations of the energetic particles that create the incandescent auroras suggest a complicated current system involving charged material lofted from volcanoes on Jupiter's moon Io.

Peer-reviewed papers with more in-depth science results from Juno's first flybys are expected to be published within the next few months.

JUNO orbiting Jupiter. Image Credit: NASA

Juno launched on Aug. 5, 2011, from Cape Canaveral, Florida, and arrived in orbit around Jupiter on July 4, 2016. During its mission of exploration, Juno soars low over the planet's cloud tops -- as close as about 2,600 miles (4,100 kilometers). During these flybys, Juno is probing beneath the obscuring cloud cover of Jupiter and studying its auroras to learn more about the planet's origins, structure, atmosphere and magnetosphere.

NASA's Jet Propulsion Laboratory, Pasadena, California, manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute in San Antonio. The Juno mission is part of the New Frontiers Program managed by NASA's Marshall Space Flight Center in Huntsville, Alabama, for the Science Mission Directorate. Lockheed Martin Space Systems, Denver, built the spacecraft. JPL is a division of Caltech in Pasadena, California.

More information on the Juno mission is available at:

http://www.nasa.gov/juno

http://missionjuno.org

The public can follow the mission on Facebook and Twitter at:

http://www.facebook.com/NASAJuno

http://www.twitter.com/NASAJuno

Images (mentioned), Text, Credits: NASA/Dwayne Brown/Laurie Cantillo/Martin Perez/JPL/DC Agle.

Greetings, Orbiter.ch

Hubble Spots Two Interacting Galaxies Defying Cosmic Convention











NASA - Hubble Space Telescope patch.

March 24, 2017


Some galaxies are harder to classify than others. Here, Hubble’s trusty Wide Field Camera 3 (WFC3) has captured a striking view of two interacting galaxies located some 60 million light-years away in the constellation of Leo (The Lion). The more diffuse and patchy blue glow covering the right side of the frame is known as NGC 3447 — sometimes NGC 3447B for clarity, as the name NGC 3447 can apply to the overall duo. The smaller clump to the upper left is known as NGC 3447A.

Overall, we know NGC 3447 comprises a couple of interacting galaxies, but we’re unsure what each looked like before they began to tear one another apart. The two sit so close that they are strongly influenced and distorted by the gravitational forces between them, causing the galaxies to twist themselves into the unusual and unique shapes seen here. NGC 3447A appears to display the remnants of a central bar structure and some disrupted spiral arms, both properties characteristic of certain spiral galaxies. Some identify NGC 3447B as a former spiral galaxy, while others categorize it as being an irregular galaxy.

Hubble Space Telescope

For Hubble’s image of the Whirlpool Galaxy, visit: 

http://hubblesite.org/

http://www.nasa.gov/hubble

http://www.spacetelescope.org/

Image, Animation, Credits: ESA/Hubble & NASA/Text Credits: European Space Agency/NASA/Karl Hille.

Best regards, Orbiter.ch

NASA Sees Tropical Cyclone Caleb's Heaviest Rainfall













NASA & JAXA -  Global Precipitation Measurement (GPM)logo.

 March 24, 2017

Caleb (South Indian Ocean)

Tropical cyclone Caleb formed on March 23 in the South Indian Ocean southwest of the Indonesian Island of Sumatra. The GPM core observatory satellite had a fairly good view of the newly formed tropical cyclone when it flew overhead and analyzed its rainfall and found the heaviest precipitation was affected by westerly winds.


Image above: On March 23, 2017 at 0756 UTC (3:56 a.m. EST) NASA/JAXA's GPM rainfall measurements showed that convective storms on tropical cyclone Caleb's western side were dropping rain at a rate of almost 84 mm (3.3 inches) per hour. Image Credits: NASA/JAXA, Hal Pierce.

The Global Precipitation Measurement mission or GPM core satellite passed over the Southern Indian Ocean on March 23, 2017 at 0756 UTC (3:56 a.m. EST). The satellite's Microwave Imager (GMI) revealed the locations of rainfall within the tropical cyclone. Rainfall measurements derived from the GMI showed that convective storms were dropping rain at a rate of almost 84 mm (3.3 inches) per hour on Caleb's western side.

GPM is a joint mission between NASA and the Japan Aerospace Exploration Agency (JAXA).

On March 24 at 0900 UTC (5 a.m. EST), Caleb had maximum sustained winds near 35 knots (40 mph/62 kph). It was centered near 14.6 degrees south latitude and 101.0 degrees east longitude, about 270 nautical miles (310.7 miles/500.4 km) east-southeast of Cocos Island. Caleb was moving to the south-southeastward at 4 knots (4.6 mph/7.4 kph).

video
NASA-JAXA's GPM Satellite Sees Caleb's Heaviest Rains West of Center

Video above: On March 23, 2017 at 0756 UTC (3:56 a.m. EST) NASA/JAXA's GPM rainfall measurements showed that convective storms on tropical cyclone Caleb's western side were dropping rain at a rate of almost 84 mm (3.3 inches) per hour. Video Credits: NASA/JAXA, Hal Pierce.

Satellite imagery on March 24 revealed that Caleb was struggling, and the Joint Typhoon Warning Center (JTWC) said that "environmental conditions are not showing any signs of improvement as the easterly flow aloft is still a dominant feature increasing the vertical wind shear."

The JTWC said that over the next 12 to 24 hours Caleb will slow as it encounters a building subtropical ridge (elongated area of high pressure) to the south. The system will assume a quasi-stationary track beyond 24 hours and weaken significantly due to increasing wind shear and cooler sea surface temperatures. Caleb is expected to dissipate in three days over the open waters of the Indian Ocean.

Related links:

GPM (Global Precipitation Measurement): http://www.nasa.gov/mission_pages/GPM/main/index.html and http://www.eorc.jaxa.jp/GPM/index_e.htm

Image (mentioned), Video (mentioned), Text, Credits: NASA's Goddard Space Flight Center/Rob Gutro/Hal Pierce.

Greetings, Orbiter.ch

OSIRIS-REx Asteroid Search Tests Instruments, Science Team











NASA - OSIRIS-REx Mission patch.

March 24, 2017

During an almost two-week search, NASA’s OSIRIS-REx mission team activated the spacecraft’s MapCam imager and scanned part of the surrounding space for elusive Earth-Trojan asteroids — objects that scientists believe may exist in one of the stable regions that co-orbits the sun with Earth. Although no Earth-Trojans were discovered, the spacecraft’s camera operated flawlessly and demonstrated that it could image objects two magnitudes dimmer than originally expected.

The spacecraft, currently on its outbound journey to the asteroid Bennu, flew through the center of Earth’s fourth Lagrangian area — a stable region 60 degrees in front of Earth in its orbit where scientists believe asteroids may be trapped, such as asteroid 2010 TK7 discovered by NASA’s Wide-field Infrared Survey Explorer (WISE) satellite in 2010. Though no new asteroids were discovered in the region that was scanned, the spacecraft’s cameras MapCam and PolyCam successfully acquired and imaged Jupiter and several of its moons, as well as Main Belt asteroids.


Animation above: The path of the Main Belt asteroid 12 Victoria, as imaged by NASA’s OSIRIS-REx spacecraft on Feb. 11, 2017, during the mission’s Earth-Trojan Asteroid Search. This animation is made of a series of five images taken by the spacecraft’s MapCam camera that were then cropped and centered on Victoria. The images were taken about 51 minutes apart and each was exposed for 10 seconds. Animation Credits: NASA/Goddard/University of Arizona.

“The Earth-Trojan Asteroid Search was a significant success for the OSIRIS-REx mission,” said OSIRIS-REx Principal Investigator Dante Lauretta of the University of Arizona, Tucson. “In this first practical exercise of the mission’s science operations, the mission team learned so much about this spacecraft’s capabilities and flight operations that we are now ahead of the game for when we get to Bennu.”

The Earth Trojan survey was designed primarily as an exercise for the mission team to rehearse the hazard search the spacecraft will perform as it approaches its target asteroid Bennu. This search will allow the mission team to avoid any natural satellites that may exist around the asteroid as the spacecraft prepares to collect a sample to return to Earth in 2023 for scientific study.

The spacecraft’s MapCam imager, in particular, performed much better than expected during the exercise. Based on the camera’s design specifications, the team anticipated detecting four Main Belt asteroids. In practice, however, the camera was able to detect moving asteroids two magnitudes fainter than expected and imaged a total of 17 Main Belt asteroids. This indicates that the mission will be able to detect possible hazards around Bennu earlier and from a much greater distance that originally planned, further reducing mission risk.

OSIRIS-REx. spacecraft at asteroid Bennu. Image Credit: NASA

Scientists are still analyzing the implications of the search’s results for the potential population of Earth-Trojan asteroids and will publish conclusions after a thorough study of mission data.

NASA's Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission's observation planning and processing. Lockheed Martin Space Systems in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA's New Frontiers Program. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the agency's New Frontiers Program for its Science Mission Directorate in Washington.

For more information on OSIRIS-REx, visit:

http://www.nasa.gov/osirisrex and http://www.asteroidmission.org

Animation (mentioned), Image (mentioned), Text, Credits: NASA’s Goddard Space Flight Center/Rob Garner/Nancy Neal Jones/University of Arizona/Erin Morton.

Greetings, Orbiter.ch

Dunes of the Southern Highlands












NASA - Mars Reconnaissance Orbiter (MRO) logo.

March 24, 2017


Sand dunes are scattered across Mars and one of the larger populations exists in the Southern hemisphere, just west of the Hellas impact basin. The Hellespontus region features numerous collections of dark, dune formations that collect both within depressions such as craters, and among "extra-crater" plains areas.

This image displays the middle portion of a large dune field composed primarily of crescent-shaped "barchan" dunes. Here, the steep, sunlit side of the dune, called a slip face, indicates the down-wind side of the dune and direction of its migration. Other long, narrow linear dunes known as "seif" dunes are also here and in other locales to the east.

NB: "Seif" comes from the Arabic word meaning "sword."

The map is projected here at a scale of 25 centimeters (9.8 inches) per pixel. [The original image scale is 25.5 centimeters (10 inches) per pixel (with 1 x 1 binning); objects on the order of 77 centimeters (30.3 inches) across are resolved.] North is up.

video
Mars Reconnaissance Orbiter (MRO), Mars orbit insertion

The University of Arizona, Tucson, operates HiRISE, which was built by Ball Aerospace & Technologies Corp., Boulder, Colo. NASA's Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Mars Reconnaissance Orbiter Project for NASA's Science Mission Directorate, Washington.

Mars Reconnaissance Orbiter (MRO): http://www.nasa.gov/mission_pages/MRO/main/index.html

Image, Video, Credits: NASA/Tony Greicius/JPL-Caltech/Univ. of Arizona.

Greetings, Orbiter.ch

Satellites shed new light on earthquakes





ESA - Sentinel-1 Mission logo.

24 March 2017

Satellite radar scans of last year’s earthquake in New Zealand are changing the way we are thinking about earthquake hazards in regions where our planet’s tectonic plates meet.

The 7.8-magnitude quake that struck New Zealand’s South Island near the town of Kaikoura on 14 November was one of the most comprehensively recorded earthquakes in history.

Kaikoura quake

Immediately after it, a team of scientists from New Zealand, the UK and the US began to study radar images from the Copernicus Sentinel-1 and Japanese ALOS-2 missions to measure the extent of the land movement.

They found that the quake caused the ground to rise by 8–10 m and offset features like roads that crossed the fault by up to 12 m. This caused large landslides and triggered a tsunami.

Satellite radar scans from before and after the quake showed that the ground-based seismic readings were not giving accurate assessments of where the ruptures were occurring.

Seismic readings are based on the shockwaves rippling through Earth. Although they are the quickest way to gather information on earthquakes, they are unable to show details in complex quakes like Kaikoura.

But radar satellites like Sentinel-1 can detect movements of millimetres in the ground and across wide areas, providing a detailed picture of land deformation and the locations of fault lines.

In the case of Kaikoura, it showed the research team that ruptures took place across many separate faults.

3D ground displacement using Sentinel-1 data

They saw that the complexity and large amount of uplift point towards how mountains in regions such as New Zealand could build rapidly.

“We’ve never seen anything like the Kaikoura quake before – it was one of the most complex ever recorded,” said Professor Tim Wright, study co-author and director of the Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics at the UK’s University of Leeds.

“An earthquake commonly ruptures across a single fault line or faults that are closely grouped, but Kaikoura ruptured at least 12 major crustal faults across two distinct active fault domains.

“This challenges many assumptions about how individual faults control earthquake ruptures.”

The study published yesterday in Science has prompted scientists to reassess how many different faults can be involved in a single earthquake, and could potentially help to re-evaluate seismic hazard models.

“There was growing evidence internationally that conventional seismic hazard models are too simple and restrictive,” said Dr Ian Hamling, a natural hazards geodesist from New Zealand research institute GNS Science and the lead author of the study.

“The message from Kaikoura is that earthquake science should be more open to a wider range of possibilities when rupture models are being developed. It underlines the importance of re-evaluating how rupture scenarios are defined for seismic hazard models. ”

Sentinel-1

New Zealand’s complex network of faults is similar to those found in western US, Japan and central Asia.

“While earthquakes like Kaikoura’s do not commonly occur, the data we’ve gathered from this event will expand our understanding of similar boundary zones around the world,” said Dr John Elliott from Leeds’ School of Earth and Environment, and co-author.

“Not only could the data help inform us for the future but it may change how we’ve interpreted ancient earthquakes.

“If an earthquake like Kaikoura’s took place thousands of years ago, current methods of paleoseismology would possibly see it as a series of earthquakes over a long period of time, rather than as one large single quake.” 

Related links:

Sentinel-1: http://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus/Sentinel-1

Study: Complex multifault rupture during the 2016 Mw 7.8 Kaikōura earthquake, New Zealand: http://science.sciencemag.org/content/early/2017/03/22/science.aam7194

European Commission Copernicus site: http://www.copernicus.eu/

COMET: http://comet.nerc.ac.uk/

GNS Science: https://www.gns.cri.nz/

Images, Text, Credits: ESA/contains modified Copernicus Sentinel data (2016), processed by J. Elliott, COMET/ATG medialab.

Best regards, Orbiter.ch

jeudi 23 mars 2017

NASA Participates in the NOAA GOES-16 Field Campaign













NASA logo / NOAA logo.

March 23, 2017

NOAA's GOES-16 satellite is ready to embark on another major milestone— The GOES-16 Field Campaign. During a three month long event, a combination of NOAA and NASA planes, sensors and satellites will fine-tune GOES-16’s brand new instruments.


Image above: Artist's concept of GOES-16 (GOES-R) in orbit. Image Credits: NOAA/NASA.

NASA successfully launched NOAA's GOES-R satellite at 6:42 p.m. EST on November 19, 2016 from Cape Canaveral Air Force Station in Florida and it was renamed GOES-16 when it achieved orbit. GOES-16 is now observing the planet from an equatorial view approximately 22,300 miles above the surface of the Earth.

Since launch the GOES-R team, which consists of scientists and engineers from both NOAA and NASA has been working around the clock to power on the satellite’s advanced instruments and to get their data back to Earth.

During this campaign, a team of instrument scientists, meteorologists, GOES-16 engineers, and specialized pilots will use an outfit of high-altitude planes, ground-based sensors, unmanned aircraft systems, the International Space Station, and the NOAA/NASA Suomi NPP polar-orbiting satellite to collect measurements across the United States.

Ranging from arid deserts and areas of dense vegetation, to open oceans and storms exhibiting lightning activity, these measurements will cover nearly everything NOAA’s GOES satellites see.


Image above: NASA’s ER-2 takes off from its base of operations at NASA’s Armstrong Flight Research Center Building 703 in Palmdale, California to test instruments that will support upcoming science flights for the Geostationary Operational Environmental Satellite-R-series. Image Credit: NASA.

While these measurements are being taken on Earth, GOES-16’s operators will be obtaining similar measurements of the same locations using two of the satellite’s most revolutionary instruments—the Advanced Baseline Imager and the Geostationary Lightning Mapper. The two data sets will be analyzed and compared by meteorologists to validate and calibrate the sensors on the satellite.

Making Data Accurate

Data from NOAA’s GOES satellites are used 24 hours a day, seven days a week for everything from flight plan forecasting and air quality alerts to potentially life-saving severe storm and tornado warnings. They provide vital information to support storm tracking, seasonal predictions, drought outlooks, and space weather predictions.

It’s NOAA’s mission to ensure that these data are as precise, accurate, and readily available as possible. Because of this, GOES-16’s data are going through an exhaustive testing phase, being checked and re-checked using measurements from a vast range of verified sources before it is put into operational use.

 GOES-16 (GOES-R) in orbit. Animation Credit: NASA

All of the GOES-16 Field Campaign information will be permanently stored as reference data at NOAA’s National Centers for Environmental Information.

Running a Field Campaign

This is the first NOAA satellite-focused field campaign since GOES-8 launched in April 1994. In many cases, the satellite’s predecessor is used to ensure that the new satellite is taking accurate measurements. When NOAA launched the Jason-3 ocean altimetry satellite, it orbited directly behind Jason-2 for several weeks in order to verify and fine-tune its instruments.

The instruments aboard GOES-16, however, are brand new and more advanced than any GOES satellite before it. So, scientists will use instruments mounted on NASA's ER-2 high-altitude aircraft, as well as various other instruments closer to Earth and one on the International Space Station, to validate what the GOES-16 satellite is seeing and fine-tune its instruments.

You Can Follow Along

The GOES-16 Field Campaign officially begins on March 22, 2017 and concludes on May 19, 2017. Throughout the campaign, progress updates, news stories, interviews, and more will be available at http://www.nesdis.noaa.gov.

Related links:

NOAA’s GOES satellites: https://www.nesdis.noaa.gov/content/currently-flying

NOAA/NASA Suomi NPP polar-orbiting satellite: http://www.jpss.noaa.gov/

Geostationary Lightning Mapper: http://www.goes-r.gov/spacesegment/glm.html

Advanced Baseline Imager: http://www.goes-r.gov/spacesegment/abi.html

Jason-3 ocean altimetry satellite: https://www.nesdis.noaa.gov/content/currently-flying

NASA's ER-2 high-altitude aircraft: https://www.nasa.gov/centers/armstrong/aircraft/ER-2/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

NOAA’s National Centers for Environmental Information: https://www.ncei.noaa.gov/

For more information about GOES-16, visit: http://www.goes-r.gov/  or http://www.nasa.gov/goes

Images (mentioned), Text, Credits: NASA/Karl Hille/NOAA/Kyle Herring.

Best regards, Orbiter.ch

NASA Examines Peru's Deadly Rainfall













NASA & JAXA - Global Precipitation Measurement (GPM) logo.

March 23, 2017

The Global Precipitation Measurement mission or GPM constellation of satellites provide data on precipitation rates and totals. Recently the GPM core observatory measured the heavy rainfall that caused extensive flooding and loss of life in Peru.


Image above: When the GPM core observatory satellite flew above Peru on March 20, 2017 at 0826 UTC (4:26 a.m. EST) GPM identified locations of storms that were dropping heavy rainfall over northwestern Peru. Image Credits: NASA/JAXA, Hal Pierce.

Extreme flooding and frequent landslides that occurred in March have forced many from their homes. An El Niño-like condition with warm ocean waters developed near Peru's coast. This extremely warm water off Peru's western coast has been blamed for promoting the development of these storms. Equatorial sea surface temperatures (SSTs) are about average elsewhere in the central and east central Pacific.

When the GPM core observatory satellite flew above Peru on March 20, 2017 at 0826 UTC (4:26 a.m. EST) GPM identified locations of storms that were dropping heavy rainfall over northwestern Peru. Data collected by GPM's Microwave Imager (GMI) and Dual-Frequency Precipitation Radar (DPR) instruments during this pass revealed that very heavy precipitation was falling in that area. GPM's radar (DPR Ku Band) data indicated that some storms were dropping rain at the extreme rate of greater than 137 mm (5.4 inches) per hour. These extreme rainfall rates were found in the line of storms extending southwestward from Peru's coast.

The GPM satellite's Radar (DPR Ku Band) were also used to examine the 3-D structure of precipitation within the storms near and over northwestern Peru. GPM's examination showed that several storms located in the Pacific had cloud tops that were reaching altitudes above 13 km (8.1 miles). GPM is a joint mission between NASA and the Japanese space agency JAXA.

video
One Week of Rainfall Over Peru

Video above: NASA's IMERG rainfall estimates were based on data collected during the period from March 14 to 21, 2017. Purple areas indicate the heaviest rainfall rates, where rain was falling at a rate of between 25 mm (~1 inch) and 50 mm (~2 inches) per hour. Video Credits: NASA/JAXA, Hal Pierce.

Integrated Multi-satellitE Retrievals for GPM (IMERG) data were used to show rainfall in areas that were not covered by the GPM core observatory satellite swath. Those estimates are the result of unifying precipitation measurements from a constellation of research and operational satellites. Those rainfall estimates were generated by NASA's Precipitation Processing System every half hour.

That data was made into an animation at NASA's Goddard Space Flight Center in Greenbelt, Maryland and showed real-time IMERG rainfall estimates based on data collected during the period from March 14 to 21, 2017. The animation of seven days of data showed scattered storms developing over Peru and Brazil and moving over Peru. The animation showed rainfall rates between 25 mm (~1 inch) and 50 mm (~2 inches) per hour in many storms.


Image above: Visualization of the GPM Core Observatory and Partner Satellites. Image Credits: NASA/JAXA.

On March 18, Peru's National Meteorological and Hydrological Service noted that from March 19 to 25, "rains will intensify on the north coast and the entire western slope of the Sierra. On the north coast (La Libertad, Lambayeque, Piura and Tumbes) heavy rains accompanied by [lightning] will intensify between March 19 and 23. In the interior of Piura and Lambayeque, the rainfall is expected to exceed 150 mm per day (~6 inches); while in the coastal zone of Piura, Lambayeque, Tumbes and the interior of La Libertad, it could exceed 50 mm per day (~ 2 inches). "

For updated conditions in Peru, visit Peru's National Meteorological and Hydrological Service website: http://www.senamhi.gob.pe/.

GPM (Global Precipitation Measurement): http://www.nasa.gov/mission_pages/GPM/main/index.html and http://www.eorc.jaxa.jp/GPM/index_e.htm

Images (mentioned), Video (mentioned), Text, Credits: NASA's Goddard Space Flight Center/Harold F. Pierce/Rob Gutro/Lynn Jenner.

R.I.P. for the victims, Orbiter.ch

Andromeda's Bright X-Ray Mystery Solved by NuSTAR












NASA - NuSTAR Mission patch.

March 23, 2017

The Milky Way's close neighbor, Andromeda, features a dominant source of high-energy X-ray emission, but its identity was mysterious until now. As reported in a new study, NASA's NuSTAR (Nuclear Spectroscopic Telescope Array) mission has pinpointed an object responsible for this high-energy radiation.

The object, called Swift J0042.6+4112, is a possible pulsar, the dense remnant of a dead star that is highly magnetized and spinning, researchers say. This interpretation is based on its emission in high-energy X-rays, which NuSTAR is uniquely capable of measuring. The object’s spectrum is very similar to known pulsars in the Milky Way.

It is likely in a binary system, in which material from a stellar companion gets pulled onto the pulsar, spewing high-energy radiation as the material heats up.

"We didn't know what it was until we looked at it with NuSTAR," said Mihoko Yukita, lead author of a study about the object, based at Johns Hopkins University in Baltimore. The study is published in The Astrophysical Journal.


Image above: NASA's Nuclear Spectroscope Telescope Array, or NuSTAR, has identified a candidate pulsar in Andromeda -- the nearest large galaxy to the Milky Way. This likely pulsar is brighter at high energies than the Andromeda galaxy's entire black hole population. Image Credits: NASA/JPL-Caltech/GSFC/JHU.

This candidate pulsar is shown as a blue dot in a NuSTAR X-ray image of Andromeda (also called M31), where the color blue is chosen to represent the highest-energy X-rays. It appears brighter in high-energy X-rays than anything else in the galaxy.

The study brings together many different observations of the object from various spacecraft. In 2013, NASA's Swift satellite reported it as a high-energy source, but its classification was unknown, as there are many objects emitting low energy X-rays in the region. The lower-energy X-ray emission from the object turns out to be a source first identified in the 1970s by NASA’s Einstein Observatory. Other spacecraft, such as NASA's Chandra X-ray Observatory and ESA's XMM-Newton had also detected it. However, it wasn't until the new study by NuSTAR, aided by supporting Swift satellite data, that researchers realized it was the same object as this likely pulsar that dominates the high energy X-ray light of Andromeda.

Traditionally, astronomers have thought that actively feeding black holes, which are more massive than pulsars, usually dominate the high-energy X-ray light in galaxies. As gas spirals closer and closer to the black hole in a structure called an accretion disk, this material gets heated to extremely high temperatures and gives off high-energy radiation. This pulsar, which has a lower mass than any of Andromeda's black holes, is brighter at high energies than the galaxy's entire black hole population.

Even the supermassive black hole in the center of Andromeda does not have significant high-energy X-ray emission associated with it. It is unexpected that a single pulsar would instead be dominating the galaxy in high-energy X-ray light.

 Nuclear Spectroscopic Telescope Array or NuSTAR. Image Credit: NASA

"NuSTAR has made us realize the general importance of pulsar systems as X-ray-emitting components of galaxies, and the possibility that the high energy X-ray light of Andromeda is dominated by a single pulsar system only adds to this emerging picture," said Ann Hornschemeier, co-author of the study and based at NASA's Goddard Space Flight Center, Greenbelt, Maryland.

Andromeda is a spiral galaxy slightly larger than the Milky Way. It resides 2.5 million light-years from our own galaxy, which is considered very close, given the broader scale of the universe. Stargazers can see Andromeda without a telescope on dark, clear nights.

"Since we can't get outside our galaxy and study it in an unbiased way, Andromeda is the closest thing we have to looking in a mirror," Hornschemeier said.

NuSTAR is a Small Explorer mission led by Caltech and managed by JPL 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 on NuSTAR, visit: http://www.nasa.gov/nustar and http://www.nustar.caltech.edu

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

Greetings, Orbiter.ch

Hubble detects supermassive black hole kicked out of galactic core












ESA - Hubble Space Telescope logo.

23 March 2017

Astronomers suspect gravitational waves

Galaxy with an ejected supermassive black hole

An international team of astronomers using the NASA/ESA Hubble Space Telescope have uncovered a supermassive black hole that has been propelled out of the centre of the distant galaxy 3C186. The black hole was most likely ejected by the power of gravitational waves. This is the first time that astronomers found a supermassive black hole at such a large distance from its host galaxy centre.

Though several other suspected runaway black holes have been seen elsewhere, none has so far been confirmed. Now astronomers using the NASA/ESA Hubble Space Telescope have detected a supermassive black hole, with a mass of one billion times the Sun’s, being kicked out of its parent galaxy. “We estimate that it took the equivalent energy of 100 million supernovae exploding simultaneously to jettison the black hole,” describes Stefano Bianchi, co-author of the study, from the Roma Tre University, Italy.

The images taken by Hubble provided the first clue that the galaxy, named 3C186, was unusual. The images of the galaxy, located 8 billion light-years away, revealed a bright quasar, the energetic signature of an active black hole, located far from the galactic core. “Black holes reside in the centres of galaxies, so it’s unusual to see a quasar not in the centre,” recalls team leader Marco Chiaberge, ESA-AURA researcher at the Space Telescope Science Institute, USA.

The team calculated that the black hole has already travelled about 35 000 light-years from the centre, which is more than the distance between the Sun and the centre of the Milky Way. And it continues its flight at a speed of 7.5 million kilometres per hour [1]. At this speed the black hole could travel from Earth to the Moon in three minutes.

Gravitational waves eject black hole from galaxy

Although other scenarios to explain the observations cannot be excluded, the most plausible source of the propulsive energy is that this supermassive black hole was given a kick by gravitational waves [2] unleashed by the merger of two massive black holes at the centre of its host galaxy. This theory is supported by arc-shaped tidal tails identified by the scientists, produced by a gravitational tug between two colliding galaxies.

According to the theory presented by the scientists, 1-2 billion years ago two galaxies — each with central, massive black holes — merged. The black holes whirled around each other at the centre of the newly-formed elliptical galaxy, creating gravitational waves that were flung out like water from a lawn sprinkler [3]. As the two black holes did not have the same mass and rotation rate, they emitted gravitational waves more strongly along one direction. When the two black holes finally merged, the anisotropic emission of gravitational waves generated a kick that shot the resulting black hole out of the galactic centre.

“If our theory is correct, the observations provide strong evidence that supermassive black holes can actually merge,” explains Stefano Bianchi on the importance of the discovery. “There is already evidence of black hole collisions for stellar-mass black holes, but the process regulating supermassive black holes is more complex and not yet completely understood.”

Hubble Space Telescope

The researchers are lucky to have caught this unique event because not every black hole merger produces imbalanced gravitational waves that propel a black hole out of the galaxy. The team now wants to secure further observation time with Hubble, in combination with the Atacama Large Millimeter/submillimeter Array (ALMA) and other facilities, to more accurately measure the speed of the black hole and its surrounding gas disc, which may yield further insights into the nature of this rare object.

Notes:

[1] As the black hole cannot be observed directly, the mass and the speed of the supermassive black holes were determined via spectroscopic analysis of its surrounding gas.

[2] First predicted by Albert Einstein, gravitational waves are ripples in space that are created by accelerating massive objects. The ripples are similar to the concentric circles produced when a rock is thrown into a pond. In 2016, the Laser Interferometer Gravitational-wave Observatory (LIGO) helped astronomers prove that gravitational waves exist by detecting them emanating from the union of two stellar-mass black holes, which are several times more massive than the Sun.

[3] The black holes get closer over time as they radiate away gravitational energy.

More information:

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

The results of the study were presented in the paper The puzzling case of the radio-loud QSO 3C 186: a gravitational wave recoiling black hole in a young radio source?, to appear in the journal Astronomy & Astrophysics.

The international team of astronomers in this study consists of Marco Chiaberge (STScI, USA; Johns Hopkins University, USA), Justin C. Ely (STScI, USA), Eileen Meyer (University of Maryland Baltimore County, USA), Markos Georganopoulos (University of Maryland Baltimore County, USA; NASA Goddard Space Flight Center, USA), Andrea Marinucci (Università degli Studi Roma Tre, Italy), Stefano Bianchi (Università degli Studi Roma Tre, Italy), Grant R. Tremblay (Yale University, USA), Brian Hilbert (STScI, USA), John Paul Kotyla (STScI, USA), Alessandro Capetti (INAF - Osservatorio Astrofisico di Torino, Italy), Stefi Baum (University of Manitoba, Canada), F. Duccio Macchetto (STScI, USA), George Miley (University of Leiden, Netherlands), Christopher O’Dea (University of Manitoba, Canada), Eric S. Perlman (Florida Institute of Technology, USA), William B. Sparks (STScI, USA) and  Colin Norman (STScI, USA; Johns Hopkins University, USA)

Links:

Images of Hubble: http://www.spacetelescope.org/images/archive/category/spacecraft/

Hubblesite release: http://hubblesite.org/news_release/news/2017-12

Science paper: http://www.spacetelescope.org/static/archives/releases/science_papers/heic1706/heic1706a.pdf

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

Laser Interferometer Gravitational-wave Observatory (LIGO): https://www.ligo.caltech.edu/

Images, Animation, Text, Credits: NASA, ESA, M. Chiaberge, A. Feild (STScI/ESA).

Best regards, Orbiter.ch

Surviving the long dark night of the Moon












ESA - European Space Agency patch.

23 March 2017

Designers of future Moon missions and bases have to contend with a chilling challenge: how might their creations endure the fortnight-long lunar night? ESA has arrived at a low-cost way of surviving.

During prolonged night, when the surface is lit only by blue Earthlight, temperatures dip below –170ºC. Some locations at higher latitudes have shorter nights, though others have much longer or even permanent darkness.

Earth from the Moon

Numerous robotic missions have perished during this prolonged cold. Russia’s Lunokhod-2 rover, for instance, failed to make it through the night in May 1973, its radioactive heater having gradually run down after four months of exploring.

The Apollo manned missions stayed on the surface only a few days at a time, and all during the early lunar morning. But future lunar settlers will have to live in the night as well as the day, bearing in mind that vital solar energy and heat would be unavailable during the 14 days of darkness.

“Up until now, radioactive heat and power sources have been the preferred solution for lunar habitats,” explains ESA’s Moritz Fontaine. “But these would multiply the cost and complexity of any expedition.

“So we’re exploring a more sustainable solution, using the capacity of moondust to absorb and store energy when hit by sunlight, then releasing this energy during the lunar night.”

Driven by the temperature difference, this heat engine would be kept running directly by the heat of the Sun during the day – illuminated surface temperatures rise well above 100ºC at the equator – while simultaneously storing excess heat in the soil.

ISS and the Moon

Once night falls, the heat engine would be kept running in turn by the gradual release of the energy from the heated soil.

“The principle has been worked out in detail,” adds Moritz. “The next step, being undertaken through ESA’s General Studies Programme, is to perform numerical and simulation studies to put values on the heat storage and electricity provision the system would enable.

“The results should then allow the construction of a small demonstrator to test the concept in practice.”

Related links:

ESA’s General Studies Programme: https://gsp.esa.int/

GSP: How to keep warm on the Moon: https://gsp.esa.int/articles/-/wcl/lGnxp6cuQgi6/10192/how-to-keep-warm-on-the-moon-

Lunar exploration interactive guide: http://lunarexploration.esa.int/#/intro

Images, Text, Credits: ESA/JAXA/NHK/Thierry Legault.

Greetings, Orbiter.ch

Supersonic plasma jets discovered








ESA - SWARM Mission logo.

23 March 2017

Information from ESA’s magnetic field Swarm mission has led to the discovery of supersonic plasma jets high up in our atmosphere that can push temperatures up to almost 10 000°C.

Presenting these findings at this week’s Swarm Science Meeting in Canada, scientists from the University of Calgary explained how they used measurements from the trio of Swarm satellites to build on what was known about vast sheets of electric current in the upper atmosphere.

Birkeland currents

The theory that there are huge electric currents, powered by solar wind and guided through the ionosphere by Earth’s magnetic field, was postulated more than a century ago by Norwegian scientist Kristian Birkeland.

It wasn’t until the 1970s, after the advent of satellites, however, that these ‘Birkeland currents’ were confirmed by direct measurements in space.

These currents carry up to 1 TW of electric power to the upper atmosphere – about 30 times the energy consumed in New York during a heatwave.

Upward and downward current sheets

They are also responsible for ‘aurora arcs’, the familiar, slow-moving green curtains of light that can extend from horizon to horizon.

While much is known about these current systems, recent observations by Swarm have revealed that they are associated with large electrical fields.

These fields, which are strongest in the winter, occur where upwards and downwards Birkeland currents connect through the ionosphere.

Heated ions travel upward

Bill Archer from the University of Calgary explained, “Using data from the Swarm satellites’ electric field instruments, we discovered that these strong electric fields drive supersonic plasma jets.

“The jets, which we call ‘Birkeland current boundary flows’, mark distinctly the boundary between current sheets moving in opposite direction and lead to extreme conditions in the upper atmosphere.

“They can drive the ionosphere to temperatures approaching 10 000°C and change its chemical composition. They also cause the ionosphere to flow upwards to higher altitudes where additional energisation can lead to loss of atmospheric material to space.”

Magnetic field sources

David Knudsen, also from the University of Calgary, added, “These recent findings from Swarm add knowledge of electric potential, and therefore voltage, to our understanding of the Birkeland current circuit, perhaps the most widely recognised organising feature of the coupled magnetosphere–ionosphere system.”

This discovery is just one of the new findings presented at the week-long science meeting dedicated to the Swarm mission. Also presented this week and focusing on Birkeland currents, for example, Swarm was used to confirm that these currents are stronger in the northern hemisphere and vary with the season.

Since they were launched in 2013, the identical Swarm satellites have been measuring and untangling the different magnetic signals that stem from Earth’s core, mantle, crust, oceans, ionosphere and magnetosphere.

Front of Swarm satellite

As well as a package of instruments to do this, each satellite has an electric field instrument positioned at the front to measure plasma density, drift and velocity.

Rune Floberghagen, ESA’s Swarm mission manager, said, “The electric field instrument is the first ionospheric imager in orbit so it’s very exciting to see such fantastic results that are thanks to this new instrument.

“The dedication of scientists working with data from the mission never ceases to amaze me and we are seeing some brilliant results, such as this, discussed at this week’s meeting.

“Swarm is really opening our eyes to the workings of the planet from deep down in Earth’s core to the highest part of our atmosphere.”

Related links:

ESA's Swarm: http://www.esa.int/Our_Activities/Observing_the_Earth/Swarm

Access Swarm data: https://earth.esa.int/web/guest/missions/esa-operational-eo-missions/swarm

Replay: Opening of Swarm and CryoSat Science Meetings: http://www.esa.int/spaceinvideos/Videos/2017/03/Opening_of_Swarm_and_CryoSat_Science_Meetings

Birkeland Centre for Space Science: https://birkeland.uib.no/

DTU Space: http://www.space.dtu.dk/english

University of Calgary–Physics and Astronomy: http://phas.ucalgary.ca/

Swarm–Aurora: https://swarm-aurora.com/

Images, Text, Credits: ESA/University of Calgary/DTU Space/ATG medialab.

Greetings, Orbiter.ch