mercredi 12 décembre 2018
NASA - InSight Mission patch.
December 12, 2018
Image above: This is NASA InSight's first selfie on Mars. It displays the lander's solar panels and deck. On top of the deck are its science instruments, weather sensor booms and UHF antenna. The selfie was taken on Dec. 6, 2018 (Sol 10). Image Credits: NASA/JPL-Caltech.
NASA's InSight lander isn't camera-shy. The spacecraft used a camera on its robotic arm to take its first selfie - a mosaic made up of 11 images. This is the same imaging process used by NASA's Curiosity rover mission, in which many overlapping pictures are taken and later stitched together. Visible in the selfie are the lander's solar panel and its entire deck, including its science instruments.
Mission team members have also received their first complete look at InSight's "workspace" - the approximately 14-by-7-foot (4-by-2-meter) crescent of terrain directly in front of the spacecraft. This image is also a mosaic composed of 52 individual photos.
In the coming weeks, scientists and engineers will go through the painstaking process of deciding where in this workspace the spacecraft's instruments should be placed. They will then command InSight's robotic arm to carefully set the seismometer (called the Seismic Experiment for Interior Structure, or SEIS) and heat-flow probe (known as the Heat Flow and Physical Properties Package, or HP3) in the chosen locations. Both work best on level ground, and engineers want to avoid setting them on rocks larger than about a half-inch (1.3 cm).
Image above: This mosaic, composed of 52 individual images from NASA's InSight lander, shows the workspace where the spacecraft will eventually set its science instruments. Image Credits: NASA/JPL-Caltech.
"The near-absence of rocks, hills and holes means it'll be extremely safe for our instruments," said InSight's Principal Investigator Bruce Banerdt of NASA's Jet Propulsion Laboratory in Pasadena, California. "This might seem like a pretty plain piece of ground if it weren't on Mars, but we're glad to see that."
InSight's landing team deliberately chose a landing region in Elysium Planitia that is relatively free of rocks. Even so, the landing spot turned out even better than they hoped. The spacecraft sits in what appears to be a nearly rock-free "hollow" - a depression created by a meteor impact that later filled with sand. That should make it easier for one of InSight's instruments, the heat-flow probe, to bore down to its goal of 16 feet (5 meters) below the surface.
JPL manages InSight for NASA's Science Mission Directorate. InSight is part of NASA's Discovery Program, managed by the agency's Marshall Space Flight Center in Huntsville, Alabama. Lockheed Martin Space in Denver built the InSight spacecraft, including its cruise stage and lander, and supports spacecraft operations for the mission.
A number of European partners, including France's Centre National d'Études Spatiales (CNES) and the German Aerospace Center (DLR), are supporting the InSight mission. CNES and the Institut de Physique du Globe de Paris (IPGP) provided the Seismic Experiment for Interior Structure (SEIS) instrument, with significant contributions from the Max Planck Institute for Solar System Research (MPS) in Germany, the Swiss Institute of Technology (ETH) in Switzerland, Imperial College London and Oxford University in the United Kingdom, and JPL. DLR provided the Heat Flow and Physical Properties Package (HP3) instrument, with significant contributions from the Space Research Center (CBK) of the Polish Academy of Sciences and Astronika in Poland. Spain's Centro de Astrobiología (CAB) supplied the wind sensors.
Seismic Experiment for Interior Structure (SEIS): https://mars.nasa.gov/insight/mission/instruments/seis/
Heat Flow and Physical Properties Package (HP3): https://mars.nasa.gov/insight/mission/instruments/hp3/
For more information about InSight, and to follow along on its flight to Mars, visit: https://www.nasa.gov/insight
Images (mentioned), Text, Credits: NASA/JPL/Andrew Good.
Publié par Orbiter.ch à 07:31
ESA - Rosetta Mission patch.
12 December 2018
A new study reveals that, contrary to first impressions, Rosetta did detect signs of an infant bow shock at the comet it explored for two years – the first ever seen forming anywhere in the Solar System.
From 2014 to 2016, ESA’s Rosetta spacecraft studied Comet 67P/Churyumov-Gerasimenko and its surroundings from near and far. It flew directly through the ‘bow shock’ several times both before and after the comet reached its closest point to the Sun along its orbit, providing a unique opportunity to gather in situ measurements of this intriguing patch of space.
Rosetta spying infant bow shock at comet
Comets offer scientists an extraordinary way to study the plasma in the Solar System. Plasma is a hot, gaseous state of matter comprising charged particles, and is found in the Solar System in the form of the solar wind: a constant stream of particles flooding out from our star into space.
As the supersonic solar wind flows past objects in its path, such as planets or smaller bodies, it first hits a boundary known as a bow shock. As the name suggests, this phenomenon is somewhat like the wave that forms around the bow of a ship as it cuts through choppy water.
Bow shocks have been found around comets, too – Halley’s comet being a good example. Plasma phenomena vary as the medium interacts with the surrounding environment, changing the size, shape, and nature of structures such as bow shocks over time.
Rosetta looked for signs of such a feature over its two-year mission, and ventured over 1500 km away from 67P’s centre on the hunt for large-scale boundaries around the comet – but apparently found nothing.
“We looked for a classical bow shock in the kind of area we’d expect to find one, far away from the comet’s nucleus, but didn’t find any, so we originally reached the conclusion that Rosetta had failed to spot any kind of shock,” says Herbert Gunell of the Royal Belgian Institute for Space Aeronomy, Belgium, and Umeå University, Sweden, one of the two scientists who led the study.
“However, it seems that the spacecraft actually did find a bow shock, but that it was in its infancy. In a new analysis of the data, we eventually spotted it around 50 times closer to the comet’s nucleus than anticipated in the case of 67P. It also moved in ways we didn’t expect, which is why we initially missed it.”
Bow shock taking shape at comet
On 7 March 2015, when the comet was over twice as far from the Sun as the Earth and heading inwards towards our star, Rosetta data showed signs of a bow shock beginning to form. The same indicators were present on its way back out from the Sun, on 24 February 2016.
This boundary was observed to be asymmetric, and wider than the fully developed bow shocks observed at other comets.
“Such an early phase of the development of a bow shock around a comet had never been captured before Rosetta,” says co-lead Charlotte Goetz of the Institute for Geophysics and Extraterrestrial Physics in Braunschweig, Germany.
“The infant shock we spotted in the 2015 data will have later evolved to become a fully developed bow shock as the comet approached the Sun and became more active – we didn't see this in the Rosetta data, though, as the spacecraft was too close to 67P at that time to detect the ‘adult’ shock. When Rosetta spotted it again, in 2016, the comet was on its way back out from the Sun, so the shock we saw was in the same state but ‘unforming’ rather than forming.”
Herbert, Charlotte, and colleagues explored data from the Rosetta Plasma Consortium, a suite of instruments comprising five different sensors to study the plasma surrounding Comet 67P. They combined the data with a plasma model to simulate the comet’s interactions with the solar wind and determine the properties of the bow shock.
The scientists found that, when the forming bow shock washed over Rosetta, the comet’s magnetic field became stronger and more turbulent, with bursts of highly energetic charged particles being produced and heated in the region of the shock itself. Beforehand, particles had been slower-moving, and the solar wind had been generally weaker – indicating that Rosetta had been ‘upstream’ of a bow shock.
“These observations are the first of a bow shock before it fully forms, and are unique in being gathered on-location at the comet and shock itself,” says Matt Taylor, ESA Rosetta Project Scientist.
“This finding also highlights the strength of combining multi-instrument measurements and simulations. It may not be possible to solve a puzzle using one dataset, but when you bring together multiple clues, as in this study, the picture can become clearer and offer real insight into the complex dynamics of our Solar System – and the objects in it, like 67P.”
Notes for Editors:
"The infant bow shock: a new frontier at a weak activity comet" by H. Gunell et al is published in Astronomy & Astrophysics, November 2018: https://doi.org/10.1051/0004-6361/201834225
The study used ion spectra from the Ion Composition Analyzer of the Rosetta Plasma Consortium (RPC-ICA), ion and electron spectra from the Ion and Electron Sensor (RPC-IES), and magnetic flux density measurements from the magnetometer instrument (RPC-MAG).
Images, Video, Text, Credits: ESA/Markus Bauer/Matt Taylor/Institute for Geophysics and Extraterrestrial Physics TU Braunschweig/Charlotte Goetz/Royal Belgian Institute for Space Aeronomy/Umeå University/Herbert Gunell.
Publié par Orbiter.ch à 07:22
mardi 11 décembre 2018
NASA - Orbiting Astronomical Observatory (OAO) 2 patch.
Dec. 11, 2018
At 3:40 a.m. EST on Saturday, Dec. 7, 1968, just three weeks before the highly anticipated launch of Apollo 8 and the first crewed flight to the Moon, an Atlas-Centaur rocket carrying NASA’s heaviest and most ambitious unpiloted satellite at the time blasted into the sky from Launch Complex 36B at Cape Canaveral Air Force Station, Florida.
Formally known as the Orbiting Astronomical Observatory (OAO) 2 and nicknamed Stargazer, it would become NASA’s first successful cosmic explorer and the direct ancestor of Hubble, Chandra, Swift, Kepler, FUSE, GALEX and many other astronomy satellites.
OAO 2 provided the first orbital stellar observations in ultraviolet light, shorter than wavelengths in the visible range spanning 3,800 (violet) to 7,500 (red) angstroms. Much of UV light is screened out by the atmosphere and unavailable to ground-based telescopes. Stargazer’s experiments made nearly 23,000 measurements, showed that young, hot stars were hotter than theoretical models of the time indicated, confirmed that comets are surrounded by vast clouds of hydrogen and discovered a curious feature of the interstellar medium that would take decades to understand.
“OAO 2 was a learning experience,” said Nancy Grace Roman, the first chief of astronomy in the Office of Space Science at NASA Headquarters, Washington. “We had to learn how to point a telescope to a single object and hold it there for a half hour or so.” This makes OAO 2 the ancestor of all space telescopes that can point to a given spot on the sky and track it for an extended period.
Seas of Infinity: OAO 2's 50th Anniversary
Video above: Watch James Kupperian Jr., the project scientist for NASA’s Orbiting Astronomical Observatories, explain the Stargazer (OAO 2) satellite and its instruments in this excerpt from “Seas of Infinity,” a 1968 NASA film about the mission. Image Credit: NASA.
The feat proved much harder to accomplish than anyone had expected a decade earlier, at the outset of the program. But the development of star trackers — small telescopes located around the spacecraft that lock onto appropriate guide stars — and associated control software enabled extended UV observations that were previously impossible.
Prior to OAO 2, ultraviolet observations of stars were acquired by suborbital sounding rockets that collect data for only five minutes each flight as they arc above much of the atmosphere. By 1968, it was estimated that sounding rockets had captured a total of three hours of stellar UV measurements in some 40 flights. OAO 2 could collect more data than this in a single day.
In June 1958, the National Academy of Science established the 15-member Space Science Board, chaired by Lloyd Berkner, to help advise the “possible new civilian space agency” — NASA, which was established the following month when the National Aeronautics and Space Act was signed into law. After the panel’s first meeting, Berkner contacted hundreds of U.S. scientists for recommendations on experiments that could be performed by a satellite with a modest payload.
At the end of the year, James Kupperian Jr., a physicist at the Naval Research Laboratory in Washington, first used “Orbiting Astronomical Observatories” in an outline of the project. The name stuck. In 1959, he moved to NASA’s Goddard Space Flight Center in Greenbelt, Maryland, to become chief of its astrophysics branch and serve as project scientist for all four OAO missions.
Image above: Technicians in a clean room at NASA’s Kennedy Space Center in Cape Canaveral, Florida, check out the Orbiting Astronomical Observatory 2 before the mission’s Dec. 7, 1968, launch. The white conical structures visible near the top of the spacecraft are two of its six star trackers, small telescopes that lock onto appropriate guide stars to keep the instruments on target. Image Credit: NASA.
Two astronomers who responded to Berkner’s request had already determined that ultraviolet observations of stars should be the initial focus for orbital astronomy. The first was Fred Whipple, director of the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, who became the principal investigator for OAO 2’s Project Celescope (from “celestial telescope”). The experiment used four television cameras to make two-degree-square images of the sky in UV wavelengths between 1,200 and 3,250 angstroms.
The other scientist was Arthur Code, a professor of astronomy at the University of Wisconsin-Madison and director of its Washburn Observatory. Code became the principal investigator on the Wisconsin Experiment Package (WEP), a suite of seven telescopes. Four were designed to measure the UV brightness of stars from 1,330 to 4,250 angstroms, and a fifth, operating from 2,130 to 3,330 angstroms, was optimized for measuring the brightness of extended objects like nebulosity. Two scanning spectrometers recorded target spectra from 1,050 to 3,800 angstroms in 100 angstrom steps and at different resolutions.
“It’s kind of interesting that this project grew out of an institution that had never done photographic astronomy,” notes Jordan Marché II, an adjunct professor of astronomy at the University of Wisconsin, Madison. At the time, imaging, processing and measuring photographic plates was a typical aspect of astronomical work, but Code and his colleagues emphasized photometric studies over photography. “They were in this completely different mode of thinking about doing research,” Marché said.
Both experiments were mounted back-to-back within the 4,436-pound (2,012 kilogram) spacecraft and looked out opposite ends, taking turns viewing the universe.
The first WEP flew aboard OAO 1 on April 8, 1966, along with X-ray and gamma-ray experiments from Lockheed, MIT and Goddard. Just seven minutes after separation from its rocket, the spacecraft began experiencing problems in its power supply, including high-voltage arcing in the star trackers. After three days and 20 orbits, controllers terminated the mission without activating any of the experiments.
Take a "Swift" Tour of the Andromeda Galaxy
Video above: Take a tour of the best-ever UV image of our neighboring Andromeda Galaxy (M31), the closest large spiral to our own. Using its Ultraviolet/Optical Telescope, NASA’s Neil Gehrels Swift Observatory acquired 330 images in three UV colors. Some 20,000 ultraviolet sources are visible here, including M32, a small galaxy in orbit around M31. Dense clusters of hot, young, blue stars light up the disk beyond the galaxy's smooth, redder central bulge. M31 is located 2.5 million light-years away. Video Credits: NASA/Swift/Stefan Immler (Goddard) and Erin Grand (University of Maryland, College Park).
OAO 2 fared much better, continuing to work until it was shut down in February 1973. Issues with the Celescope — primarily a gradual loss of sensitivity in its modified TV tube detectors, called uvicons — resulted in the experiment being turned off in April 1970. By then, the Celescope had captured some 8,500 images across 10 percent of the sky, and Whipple’s team ultimately published a catalog of 5,068 UV stars.
The WEP experienced fewer problems. Some weeks after launch, a calibration source in the nebula photometer stuck in place, allowing no further data to be returned from that telescope. But while the filters in the other telescopes showed some degradation in orbit, the instruments performed well and were functioning when the spacecraft was shut down.
In addition to providing important UV data on some 1,200 stars, the WEP also observed planets, galaxies and comets. One of its most striking finds occurred in early 1970, when the instrument observed comet Tago-Sato-Kosaka, which had recently rounded the Sun and was headed back out into deep space. Observations showed the comet was surrounded by a UV-emitting cloud of hydrogen bigger than the Sun, dwarfing the comet’s visible structure; a similar feature was seen around comet Bennett later that year. These findings confirmed earlier predictions based on the idea that a comet’s tiny solid nucleus was largely made of frozen water. Solar ultraviolet light breaks up water molecules streaming off the icy nucleus, resulting in a sparse but vast envelope of hydrogen atoms that scatters UV sunlight.
Image above: An illustration of OAO 2, nicknamed Stargazer, in orbit around Earth. Image Credit: NASA.
One of the most interesting results from OAO 2 involved interstellar extinction, a measure of the way matter between the stars absorbs and scatters light. The WEP showed there was a narrow extinction “bump” — that is, an increase in the way UV light was absorbed or scattered — centered at about 2,175 angstroms. Early speculation suggested that this feature may represent evidence for graphite dust grains. But theorists have introduced more exotic possibilities in the decades since, including nanodiamonds, graphite “onions,” molecules called polycyclic aromatic hydrocarbons (PAHs) and fullerenes, large, hollow soccer-ball-shaped molecules formed by carbon atoms.
“The problem is that many of the exotic forms discussed are not likely to be sufficiently abundant in interstellar space,” said John Bradley, a researcher at the University of Hawaii at Manoa who has been intrigued by the UV bump for 20 years. Bradley and his colleagues identified a similar spectral feature from PAHs embedded within interplanetary dust particles. “PAHs are everywhere,” he said, “and they are most likely the source of the bump, possibly with the addition of closely related fullerene-like molecules.”
GALEX (Galaxy Evolution Explorer): http://www.nasa.gov/mission_pages/galex/index.html
Hubble Space Telescope (HST): https://www.nasa.gov/mission_pages/hubble/main/index.html
NASA History: https://www.nasa.gov/topics/history/index.html
Images (mentioned), Videos (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center, by Francis Reddy.
Publié par Orbiter.ch à 17:32
ROSCOSMOS - Soyuz MS-09 Mission patch / EVA - Extra Vehicular Activities patch.
December 11, 2018
Expedition 57 Flight Engineers Oleg Kononenko and Sergey Prokopyev of Roscosmos completed a spacewalk lasting 7 hours and 45 minutes.
Image above: Spacewalker Oleg Kononenko is on the Strela boom getting ready for inspection work on the Soyuz crew vehicle. Image Credit: NASA TV.
The two cosmonauts opened the hatch to the Pirs docking compartment to begin the spacewalk at 10:59 a.m. EST. They re-entered the airlock and closed the hatch at 6:44 p.m. EST.
Soyuz MS-09 inspected by cosmonauts
During the spacewalk, the two examined the external hull of the Russian Soyuz MS-09 spacecraft attached to the space station, took images, and applied a thermal blanket. They also retrieved science experiments from the Rassvet module before heading back inside.
It was the 213th spacewalk in support of International Space Station assembly, maintenance and upgrades, the fourth for Kononenko, and the second for Prokopyev.
Image above: A pair of empty Orlan spacesuits are seen inside the Pirs Docking Compartment airlock where cosmonauts stage Russian spacewalks. Image Credit: NASA.
Prokopyev, NASA astronaut Serena Auñón-Chancellor, and ESA (European Space Agency) astronaut Alexander Gerst are scheduled to depart the station in the Soyuz MS-09 at 8:42 p.m. Dec. 19, returning home to Earth after a six-and-half-month mission.
Pirs docking compartment: https://www.nasa.gov/mission_pages/station/structure/elements/pirs-docking-compartment
213th spacewalk: http://www.nasa.gov/mission_pages/station/spacewalks
Soyuz MS-09: https://www.nasa.gov/feature/soyuz-launches-arrivals-and-departures
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), Video, Text, Credits: NASA/Mark Garcia/NASA TV/SciNews.
Best regards, Orbiter.ch
Publié par Orbiter.ch à 16:22
ISS - Expedition 57 Mission patch.
Dec. 11, 2018
NASA astronaut Anne McClain, David Saint-Jacques of the Canadian Space Agency, and Oleg Konenenko of the Russian space agency Roscosmos joined Expedition 57 Commander Alexander Gerst of ESA (European Space Agency), Serena Auñón-Chancellor of NASA, and Sergey Prokopyev of Roscosmos aboard the International Space Station last week.
Image above: NASA astronaut Anne McClain, David Saint-Jacques of the Canadian Space Agency, and Oleg Konenenko of the Russian space agency Roscosmos joined Expedition 57 Commander Alexander Gerst of ESA (European Space Agency),Serena Auñón-Chancellor of NASA, and Sergey Prokopyev of Roscosmos aboard the space station last week. Image Credit: NASA.
In addition to expanding the crew, the station also received tons of new science aboard the SpaceX CRS-16 Dragon. Science included investigations like Molecular Muscle, Rodent Research-8, Perfect Crystals and many more.
Image above: Dragon’s 16th mission to the orbital lab will deliver almost 5,700 pounds of science, crew supplies and hardware. Image Credit: NASA.
Here’s a look at some of the science conducted last week aboard the orbiting lab:
Habitats readied for rodent investigation
Spending a lot of time in space causes changes to the human body, including bone, muscle, the cardiovascular system and the immune system. Similar changes occur as people age on Earth. That makes spaceflight an opportunity to study – and perhaps lessen – the effects of aging.
Rodent Research-8 (RR-8) examines the physiology of aging and the effect of age on disease progression using groups of young and old mice flown in space and kept on Earth. Last week, crew members prepared for the arrival of the mice by installing two habitats and stowing habitats used in previous investigations.
Spinning science: cement solidification in space
Solidifying cement in microgravity minimizes gravity-driven phenomena and creates a different microstructure than that observed in typical laboratory conditions on Earth. Understanding the process in microgravity is essential to advancing the ultimate use of cement in extraterrestrial settings, such as Mars or the Moon.
MVP-Cell-05 investigates the complex process of cement solidification at various levels of gravity (lunar, Mars and 0.7 g). The MVP facility, used to conduct research in space with a wide variety of sample types, includes internal carousels that simultaneously can produce up to 2 g of artificial gravity.
Last week, a crewmember mixed control and experiment samples within the portable glove bag. Eight experiment samples were inserted into the MVP centrifuge facility to simulate 0.7 g.
Learn more about the MVP facility here: https://www.nasa.gov/mission_pages/station/research/news/Spinning_Science_MVP_Arrives_At_ISS
Image above: NASA astronaut and station commander Alexander Gerst working on the CASIS PCG-16 investigation. CASIS PCG-16 evaluates growth of LRRK2 protein crystals in microgravity, a protein implicated in Parkinson’s disease. Image Credit: NASA.
Virtual reality sessions test sensory perception aboard orbiting lab
The VECTION investigation, sponsored by the Canadian Space Agency (CSA), examines how lack of gravity disrupts a person’s ability to visually interpret motion, orientation and distance. A better understanding of the vestibular system and its involvement in sensory perception – learning when and how to trust their eyes, touch and other senses – could help humans in a range of environments, from under water to outer space.
Last week, a crew member performed configuration steps for the VECTION software, as well as verification of the virtual reality headset and trackball components. Later, crew members deployed the VECTION hardware and performed experiment sessions, downlinking data to the ground afterwards.
To learn more about this investigation, click here: https://www.nasa.gov/mission_pages/station/research/news/human_senses_in_space
Other work was done on these investigations:
- CASIS PCG 16 evaluates growth of LRRK2 protein crystals in microgravity. LRRK2 is implicated in Parkinson’s disease, but crystals of the protein grown on Earth are too small and compact to study: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7855
- Cemsica tests using particles of calcium-silicate (C-S) to synthesize nanoporous membranes (those with pores 100 nanometers or smaller) that can separate carbon dioxide (CO2) molecules from air or other gases: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7721
- The Marrow investigation studies the effect of microgravity on bone marrow. It is believed that microgravity, like long-duration bed rest on Earth, has a negative effect on the bone marrow and the blood cells that are produced in the bone marrow: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1673
- Molecular Muscle examines the molecular mechanisms behind muscle loss and the potential for developing countermeasures targeting those mechanisms: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7576
- Behavioral Core Measures examines an integrated, standardized suite of measurements for its ability to rapidly and reliably assess the risk of adverse cognitive or behavioral conditions and psychiatric disorders during long-duration spaceflight: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7537
- Standard Measures collects a set of core measurements related to many human spaceflight risks from astronauts before, during, and after long-duration missions. The aim is to ensure consistent capture of an optimized, minimal set of measures from crew members until the end of the International Space Station Program in order to characterize the adaptive responses to and risks of living in space: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7711
Space to Ground: Four Orbits Later: 12/07/2018
Expedition 57: https://www.nasa.gov/mission_pages/station/expeditions/expedition57/index.html
SpaceX CRS-16 Dragon: https://www.nasa.gov/mission_pages/station/research/news/spx16-research
Molecular Muscle: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7576
Rodent Research-8: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7713
Perfect Crystals: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7617
Canadian Space Agency (CSA): https://www.canada.ca/en/space-agency.html
Spot the Station: https://spotthestation.nasa.gov/
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), Video (NASA), Text, Credits: NASA/Michael Johnson/Vic Cooley, Lead Increment Scientist Expeditions 57/58.
Best regards, Orbiter.ch
Publié par Orbiter.ch à 13:58
lundi 10 décembre 2018
NASA - IceSat-2 Mission patch / NASA - Operation IceBridge patch.
Dec. 10, 2018
East Antarctica has the potential to reshape coastlines around the world through sea level rise, but scientists have long considered it more stable than its neighbor, West Antarctica. Now, new detailed NASA maps of ice velocity and elevation show that a group of glaciers spanning one-eighth of East Antarctica’s coast have begun to lose ice over the past decade, hinting at widespread changes in the ocean.
Image above: A group of four glaciers in an area of East Antarctica called Vincennes Bay, west of the massive Totten Glacier, have lowered their surface height by about 9 feet since 2008, hinting at widespread changes in the ocean. The data used for this map is an early version of the NASA MEaSUREs ITS_LIVE project and was produced by Alex Gardner, NASA-JPL. Image Credits: NASA Earth Observatory/Joshua Stevens.
In recent years, researchers have warned that Totten Glacier, a behemoth that contains enough ice to raise sea levels by at least 11 feet, appears to be retreating because of warming ocean waters. Now, researchers have found that a group of four glaciers sitting to the west of Totten, plus a handful of smaller glaciers farther east, are also losing ice.
"Totten is the biggest glacier in East Antarctica, so it attracts most of the research focus," said Catherine Walker, a glaciologist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who presented her findings at a press conference on Monday at the American Geophysical Union meeting in Washington. "But once you start asking what else is happening in this region, it turns out that other nearby glaciers are responding in a similar way to Totten."
For her research, Walker used new maps of ice velocity and surface height elevation that are being created as part of a new NASA project called Inter-mission Time Series of Land Ice Velocity and Elevation, or ITS_LIVE. Researchers with ITS_LIVE will be launching a new initiative in early 2019 to track the movement of the world’s ice, which includes the creation of a 30-year record of satellite observations of changes in the surface elevation of glaciers, ice sheets and ice shelves, and a detailed record of variations in ice velocity starting in 2013.
Walker found that four glaciers west of Totten, in an area called Vincennes Bay, have lowered their surface height by about 9 feet since 2008 – before that year, there had been no measured change in elevation for these glaciers. Farther east, a collection of glaciers along the Wilkes Land coast have approximately doubled their rate of lowering since around 2009, and their surface is now going down by about 0.8 feet every year.
Image above: This map shows the flow of the Antarctic ice sheet as measured from the tracking of subtle surface features across millions of Landsat repeat image pairs. The "donut hole" marks the maximum latitude visible by the Landsat satellites. The data used for this map is an early version of the NASA MEaSUREs ITS_LIVE project and was produced by Alex Gardner, NASA-JPL. Image Credits: NASA Earth Observatory/Joshua Stevens.
These levels of ice loss are small when compared to those of glaciers in West Antarctica. But still, they speak of nascent and widespread change in East Antarctica.
"The change doesn’t seem random; it looks systematic," said Alex Gardner, a glaciologist with NASA’s Jet Propulsion Laboratory in Pasadena, California, lead of ITS_LIVE and a participant in the press conference. "And that systematic nature hints at underlying ocean influences that have been incredibly strong in West Antarctica. Now we might be finding clear links of the ocean starting to influence East Antarctica."
Walker used simulations of ocean temperature from a model and compared them to actual measurements from sensor-tagged marine mammals. She found that recent changes in winds and sea ice have resulted in an increase to the heat delivered by the ocean waters to the glaciers in Wilkes Land and Vincennes Bay.
"Those two groups of glaciers drain the two largest subglacial basins in East Antarctica, and both basins are grounded below sea level,” Walker said. "If warm water can get far enough back, it can progressively reach deeper and deeper ice. This would likely speed up glacier melt and acceleration, but we don’t know yet how fast that would happen. Still, that’s why people are looking at these glaciers, because if you start to see them picking up speed, that suggests that things are destabilizing."
Image above: A glacier in East Antarctica, as seen during an Operation IceBridge flight in November 2013. Image Credits: NASA/Michael Studinger.
There is a lot of uncertainty about how a warming ocean might affect these glaciers, due to how little explored that remote area of East Antarctica is. The main unknowns have to do with the topography of the bedrock below the ice and the bathymetry (shape) of the ocean floor in front of and below the ice shelves, which govern how ocean waters circulate near the continent and bring ocean heat to the ice front.
For example, if it turned out that the terrain beneath the glaciers sloped upward inland of the grounding line –the point where glaciers reach the ocean and begin floating over sea water forming an ice shelf— and featured ridges that provided friction, this configuration would slow down the flow and loss of ice. This type of landscape would also limit the access of warm circumpolar deep ocean waters to the ice front.
A much worse scenario for ice loss would be if the bedrock under the glaciers sloped downward inland of the grounding line. In that case, the ice base would get deeper and deeper as the glacier retreated and, as ice calved off, the height of the ice face exposed to the ocean would increase. That would allow for more melt at the front of the glacier and also make the ice cliff more unstable, increasing the rate of iceberg release. This kind of terrain would make it easier for warm circumpolar deep water to reach the ice front, sustaining high melt rates near the grounding line.
"Heightened attention needs to be given to these glaciers: We need to better map the topography and we need to better map the bathymetry," Gardner said. "Only then can we be more conclusive in determining whether, if the ocean warms, these glaciers will enter a phase of rapid retreat or stabilize on upstream topographic features."
NASA’s AGU website: https://www.nasa.gov/topics/earth/agu/index.html
NASA’s Earth Portal: https://www.nasa.gov/topics/earth/index.html
Images (mentioned), Text, Credits: NASA/Sara Blumberg/Earth Science News Team, by Maria-José Viñas.
Publié par Orbiter.ch à 18:48
NASA - Suomi NPP Mission patch.
Dec. 10, 2018
When Hurricane Maria struck Puerto Rico head-on as a Category 4 storm with winds up to 155 miles per hour in September 2017, it damaged homes, flooded towns, devastated the island's forests and caused the longest electricity black-out in U.S. history.
Image above: On Sept. 21, 2017, NASA-NOAA's Suomi NPP satellite provided this thermal image of Hurricane Maria after it moved off the coast of Puerto Rico. Image Credit: NOAA/NASA Goddard Rapid Response Team.
Two new NASA research efforts delve into Hurricane Maria's far-reaching effects on the island's forests as seen in aerial surveys and on its residents' energy and electricity access as seen in data from space. The findings, presented Monday at the American Geophysical Union meeting in Washington, illustrate the staggering scope of Hurricane Maria's damage to both the natural environment and communities.
An Island Gone Dark
At night, Earth is lit up in bright strings of roads dotted with pearl-like cities and towns as human-made artificial light takes center stage. During Hurricane Maria, Puerto Rico's lights went out.
In the days, weeks and months that followed, research physical scientist Miguel Román at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and his colleagues developed neighborhood-scale maps of lighting in communities across Puerto Rico. To do this, they combined daily satellite data of Earth at night from the NASA/NOAA Suomi National Polar-orbiting Partnership satellite with USGS/NASA Landsat data and OpenStreetMap data. They monitored where and when the electricity grid was restored, and analyzed the demographics and physical attributes of neighborhoods longest affected by the power outages.
NASA's Black Marble Maps Puerto Rico's Energy Use After Hurricane Maria
Video above: Credits: NASA's Goddard Space Flight Center.
A disproportionate share of long-duration power failures occurred in rural communities. The study found that 41 percent of Puerto Rico’s rural municipalities experienced prolonged periods of outage, compared to 29 percent of urban areas. When combined, power failures across Puerto Rico’s rural communities accounted for 61 percent of the estimated cost of 3.9 billion customer-interruption hours, six months after Hurricane Maria. These regions are primarily rural in the mountainous interior of the island where residents were without power for over 120 days. However, even more heavily populated areas had variable recovery rates between neighborhoods, with suburbs often lagging behind urban centers.
The difference between urban and rural recovery rates is in part because of the centralized set-up of Puerto Rico's energy grid that directs all power to prioritized locations rather than based on proximity to the nearest power plant, Román said. Areas were prioritized, in part, based on their population densities, which is a disadvantage to rural areas. Within cities, detached houses and low-density suburban areas were also without power longer.
"It’s not just the electricity being lost," Román said. "Storm damage to roads, high-voltage power lines and bridges resulted in cascading failures across multiple sectors, making many areas inaccessible to recovery efforts. So people lost access to other basic services like running water, sanitation, and food for extended time periods."
The absence of electricity as seen in the night lights data offers a new way to visualize storm impacts to vulnerable communities across the entirety of Puerto Rico on a daily basis. It's an indicator visible from space that critical infrastructure, beyond power, may be damaged as well, including access to fuel and other necessary supplies. The local communities with long-duration power outages also correspond to areas that reported lack of access to medical resources.
The next step for Román when looking at future disasters is to go beyond night lights data and sync it up with updated information on local infrastructure – roads, bridges, internet connectivity, clean water sources – so that when the lights are out, disaster responders can cross-reference energy data with other infrastructure bottlenecks that needs to be solved first, which would help identify at-risk communities and allocate resources.
The Buzz-Cut Forest
Hurricane Maria's lashing rain and winds also transformed Puerto Rico's lush tropical rainforest landscape. Research scientist Doug Morton of Goddard was part of the team of NASA researchers who had surveyed Puerto Rico's forests six months before the storm. The team used Goddard’s Lidar, Hyperspectral, and Thermal (G-LiHT) Airborne Imager, a system designed to study the structure and species composition of forests. Shooting 600,000 laser pulses per second, G-LiHT produces a 3D view of the forest structure in high resolution, showing individual trees in high detail from the ground to treetop. In April 2018, post-Maria, the team went back and surveyed the same tracks as in 2017.
Comparing the before and after data, the team found that 40 to 60 percent of the tall trees that formed the canopy of the forest were damaged, either snapped in half, uprooted by strong winds or lost large branches.
3-D Views of Puerto Rico's Forests After Hurricane Maria
Video above: Credits: NASA's Goddard Space Flight Center.
"Maria gave the island's forests a haircut," said Morton. "The island lost so many large trees that the overall height of forests was shortened by one-third. We basically saw 60 years' worth of what we would otherwise consider natural treefall disturbances happen in one day."
The extensive damage to Puerto Rico's forests had far-reaching effects, Morton said. Fallen trees that no longer stabilize soil on slopes with their roots as well as downed branches can contribute to landslides and debris flows, increased erosion, and poor water quality in streams and rivers where sediments build up.
In addition, the lidar surveys across the island corroborate findings presented at AGU by ecologist Maria Uriarte at Columbia University in New York City, who looked at tree death and damage rates in ground plots at the National Science Foundation Luquillo Long-Term Ecological Research site. Uriarte found certain tree species were more susceptible to the high wind damage, while others such as the palms, survived at higher rates, along with shrubs and shorter trees in the understory.
Morton and Uriarte will continue to follow the fate of Puerto Rican forests as they recover from hurricane damages using laser technology from the ground to make detailed measurements of forest regrowth.
NASA Measures Hurricane Maria's Torrential Rainfall, Sees Eye Re-open
NASA Looks Within Category 5 Hurricane Maria Before and After First Landfall
NASA Sees Maria Intensify into a Major Hurricane
NASA Finds Very Heavy Rainfall in Hurricane Maria
NASA Infrared Data Targets Maria's Strongest Side
For more information on NASA's Black Marble data, visit: https://viirsland.gsfc.nasa.gov/Products/NASA/BlackMarble.html
For more information on NASA's G-LiHT data: https://gliht.gsfc.nasa.gov/
Suomi NPP (National Polar-orbiting Partnership): http://www.nasa.gov/mission_pages/NPP/main/index.html
Image (mentioned), Videos (mentioned), Text, Credits: NASA/Sara Blumberg/Earth Science News Team, by Ellen Gray.
Publié par Orbiter.ch à 16:41
ISS - International Space Station logo.
Dec. 10, 2018
Membranes – thin barriers that allow some things to pass through, but stop others – occur naturally in cells and tissues. Artificial membranes modeled after natural ones are used in a number of applications, including separating and removing carbon dioxide (CO2) from waste gases released in energy production.
An investigation on the International Space Station looks at whether making artificial membranes in microgravity can help reduce greenhouse gas emissions on Earth.
Image above: Cemsica calcium silicate nanoparticles, which have diameters as small as a few nanometers. Image Credits: Cemsica.
The Cemsica investigation uses particles of calcium-silicate to make membranes with openings or pores smaller than 100 nanometers, known as nanoporous membranes, to separate carbon dioxide molecules from air and other gases. These membranes are as thin as a human hair. Membranes already represent one of the most energy-efficient and cost-effective technologies for separating and removing CO2 from waste gases.
The investigation takes its name from Houston-based Cemsica, LLC, a company that is commercializing this gas separation membrane technology. “Our technology not only controls the shape and size of the membrane pores,” said Negar Rajabi, principal investigator and Cemsica founder and CEO. “It also creates an affinity to certain gases such as CO2, meaning those gases are drawn to the membrane.” That gives the membranes significantly greater separation capability.
Creating these membranes in microgravity may resolve current challenges in the technology, including high-cost and manufacturing difficulties, Rajabi added. Resolving those challenges could lead to development of lower-cost membranes with improved performance and stability, as well as improved manufacturing techniques.
Large gaps or separation of the calcium-silicate particles and substrate material adversely affect membrane performance. Microgravity minimizes these problems since calcium-silicate crystals grow larger and in more organized structures in space, creating organized, defect-free pores and higher surface area.
Image above: The rise of carbon dioxide in the atmosphere. In 2013, CO2 levels surpassed 400 ppm for the first time in recorded history. Image Credits: National Oceanic and Atmospheric Administration.
Surface area plays a key role in gas separation in microgravity, where separation occurs only through diffusion. The higher surface area remains a significant factor in improved gas separation even in Earth’s gravity because it creates higher surface tension that facilitates affinity-based gas separation.
This investigation was sponsored by the International Space Station U.S. National Laboratory. “Cemsica’s novel approach to gas separation membranes in microgravity conditions provides the energy community a new avenue for evaluating unique ways to reduce the effects of CO2 emissions on our planet,” said Patrick O’Neill with the National Lab. “The project also could reduce energy consumption while improving the chemical stability of products on Earth.”
Lessons learned from the investigation may enable Earth-based production of membranes that can separate and capture CO2 from fossil-fuel power plants using half the energy of current methods. Roughly 40 percent of CO2 emissions in the U.S. come from these power plants. Other potential applications include oil and gas production and water treatment.
These membrane pores may be tiny, but they have very big potential.
Cemsica, LLC: http://www.cemsica.com/
International Space Station U.S. National Laboratory: http://www.iss-casis.org/
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/Michael Johnson/JSC/International Space Station Program Science Office/Melissa Gaskill.
Best regards, Orbiter.ch
Publié par Orbiter.ch à 15:33
CERN - European Organization for Nuclear Research logo.
Dec. 10, 2018
After an outstanding performance, the Large Hadron Collider (LHC), the accelerator complex and the experiments are now stopping for two years for major improvements and upgrading.
Image above: The Superconducting Magnets and Circuits Consolidation project which took place during the first Long Shutdown (LS1) (Image: Maximilien Brice/CERN).
Geneva, 3 December 2018. Early this morning, operators of the CERN Control Centre turned off the Large Hadron Collider (LHC), ending the very successful second run of the world’s most powerful particle accelerator. CERN’s accelerator complex will be stopped for about two years to enable major upgrade and renovation works.
During this second run (2015–2018), the LHC performed beyond expectations, achieving approximately 16 million billion proton-proton collisions at an energy of 13 TeV and large datasets for lead-lead collisions at an energy of 5.02 TeV. These collisions produced an enormous amount of data, with more than 300 petabytes (300 million gigabytes) now permanently archived in CERN’s data centre tape libraries. This is the equivalent of 1000 years of 24/7 video streaming! By analysing these data, the LHC experiments have already produced a large amount of results, extending our knowledge of fundamental physics and of the Universe.
“The second run of the LHC has been impressive, as we could deliver well beyond our objectives and expectations, producing five times more data than during the first run, at the unprecedented energy of 13 TeV,” says Frédérick Bordry, CERN Director for Accelerators and Technology. “With this second long shutdown starting now, we will prepare the machine for even more collisions at the design energy of 14 TeV.”
“In addition to many other beautiful results, over the past few years the LHC experiments have made tremendous progress in the understanding of the properties of the Higgs boson,” adds Fabiola Gianotti, CERN Director-General. “The Higgs boson is a special particle, very different from the other elementary particles observed so far; its properties may give us useful indications about physics beyond the Standard Model.”
A cornerstone of the Standard Model of particle physics – the theory that best describes the elementary particles and the forces that bind them together – the Higgs boson was discovered at CERN in 2012 and has been studied ever since. In particular, physicists are analysing the way it decays or transforms into other particles, to check the Standard Model’s predictions. Over the last three years, the LHC experiments extended the measurements of rates of Higgs boson decays, including the most common, but hard-to-detect, decay into bottom quarks, and the rare production of a Higgs boson in association with top quarks. The ATLAS and CMS experiments also presented updated measurement of the Higgs boson mass with the best precision to date.
Besides the Higgs boson, the LHC experiments produced a wide range of results and hundreds of scientific publications, including the discovery of exotic new particles such as Ξcc++ and pentaquarks with the LHCb experiment, and the unveiling of so-far unobserved phenomena in proton–proton and proton-lead collisions at ALICE.
During the two-year break, Long Shutdown 2 (LS2), the whole accelerator complex and detectors will be reinforced and upgraded for the next LHC run, starting in 2021, and the High-Luminosity LHC (HL-LHC) project, which will start operation after 2025. Increasing the luminosity of the LHC means producing far more data.
“The rich harvest of the second run enables the researchers to look for very rare processes,” explains Eckhard Elsen, Director for Research and Computing at CERN. “They will be busy throughout the shutdown examining the huge data sample for possible signatures of new physics that haven’t had the chance to emerge from the dominant contribution of the Standard Model processes. This will guide us into the HL-LHC when the data sample will increase by yet another order of magnitude.”
Large Hadron Collider (LHC)
Several components of the accelerator chain (injectors) that feed the LHC with protons will be renewed to produce more intense beams. The first link in this chain, the linear accelerator Linac2, will be replaced by Linac4. The new linear accelerator will accelerate H- ions, which are later stripped to protons, allowing the preparation of brighter beams. The second accelerator in the chain, the Proton Synchrotron Booster, will be equipped with completely new injection and acceleration systems. The Super Proton Synchrotron (SPS), the last injector before the LHC, will have new radio frequency power to accelerate higher beam intensities, and will be connected to upgraded transfer lines.
Some improvements of the LHC are also planned during LS2. The bypass diodes – the electrical components that protect the magnets in case of quench – will be shielded, as a prerequisite for extending the LHC beam energy to 7 TeV after the LS2, and more than 20 main superconducting magnets will be replaced. Moreover, civil engineering works for the HL-LHC that started in June 2018 will continue, new galleries will be connected to the LHC tunnel, and new powerful magnet and superconducting technologies will be tested for the first time.
All the LHC experiments will upgrade important parts of their detectors in the next two years. Almost the entire LHCb experiment will be replaced with faster detector components that will enable the collaboration to record events at full proton-proton rate. Similarly, ALICE will upgrade the technology of its tracking detectors. ATLAS and CMS will undergo improvements and start to prepare for the big experiments’ upgrade for HL-LHC.
Proton beams will resume in spring 2021 with the LHC’s third run.
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.
Higgs boson: https://home.cern/science/physics/higgs-boson
ATLAS paper: https://arxiv.org/pdf/1806.00242.pdf
CMS paper: https://arxiv.org/abs/1706.09936
High-Luminosity LHC (HL-LHC) project: https://home.cern/science/accelerators/high-luminosity-lhc
Large Hadron Collider (LHC): https://home.web.cern.ch/fr/topics/large-hadron-collider
For more information about European Organization for Nuclear Research (CERN), Visit: https://home.cern/
Image, Animation, Text, Credit: CERN.
Best regards, Orbiter.ch
Publié par Orbiter.ch à 15:17
NASA - OSIRIS-REx Mission patch.
Dec. 10, 2018
Image above: This mosaic image of asteroid Bennu is composed of 12 PolyCam images collected on Dec. 2 by the OSIRIS-REx spacecraft from a range of 15 miles (24km). Image Credits: NASA/Goddard/University of Arizona.
Recently analyzed data from NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) mission has revealed water locked inside the clays that make up its scientific target, the asteroid Bennu.
During the mission’s approach phase, between mid-August and early December, the spacecraft traveled 1.4 million miles (2.2 million km) on its journey from Earth to arrive at a location 12 miles (19 km) from Bennu on Dec. 3. During this time, the science team on Earth aimed three of the spacecraft’s instruments towards Bennu and began making the mission’s first scientific observations of the asteroid. OSIRIS-REx is NASA’s first asteroid sample return mission.
Data obtained from the spacecraft’s two spectrometers, the OSIRIS-REx Visible and Infrared Spectrometer (OVIRS) and the OSIRIS-REx Thermal Emission Spectrometer (OTES), reveal the presence of molecules that contain oxygen and hydrogen atoms bonded together, known as “hydroxyls.” The team suspects that these hydroxyl groups exist globally across the asteroid in water-bearing clay minerals, meaning that at some point, Bennu’s rocky material interacted with water. While Bennu itself is too small to have ever hosted liquid water, the finding does indicate that liquid water was present at some time on Bennu’s parent body, a much larger asteroid.
OSIRIS-REx arrival at Bennu. Animation Credit: NASA
“The presence of hydrated minerals across the asteroid confirms that Bennu, a remnant from early in the formation of the solar system, is an excellent specimen for the OSIRIS-REx mission to study the composition of primitive volatiles and organics,” said Amy Simon, OVIRS deputy instrument scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “When samples of this material are returned by the mission to Earth in 2023, scientists will receive a treasure trove of new information about the history and evolution of our solar system.”
Additionally, data obtained from the OSIRIS-REx Camera Suite (OCAMS) corroborate ground-based telescopic observations of Bennu and confirm the original model developed in 2013 by OSIRIS-REx Science Team Chief Michael Nolan and collaborators. That model closely predicted the asteroid’s actual shape, with Bennu’s diameter, rotation rate, inclination, and overall shape presented almost exactly as projected.
One outlier from the predicted shape model is the size of the large boulder near Bennu’s south pole. The ground-based shape model calculated this boulder to be at least 33 feet (10 meters) in height. Preliminary calculations from OCAMS observations show that the boulder is closer to 164 feet (50 meters) in height, with a width of approximately 180 feet (55 meters).
Bennu’s surface material is a mix of very rocky, boulder-filled regions and a few relatively smooth regions that lack boulders. However, the quantity of boulders on the surface is higher than expected. The team will make further observations at closer ranges to more accurately assess where a sample can be taken on Bennu to later be returned to Earth.
3D Shape Model of Asteroid Bennu
Video above: This preliminary shape model of asteroid Bennu was created from a compilation of images taken by OSIRIS-REx’s PolyCam camera during the spacecraft’s approach toward Bennu during the month of November. This 3D shape model shows features on Bennu as small as six meters. Video Credits: NASA/Goddard/University of Arizona.
“Our initial data show that the team picked the right asteroid as the target of the OSIRIS-REx mission. We have not discovered any insurmountable issues at Bennu so far,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson. “The spacecraft is healthy and the science instruments are working better than required. It is time now for our adventure to begin.”
The mission currently is performing a preliminary survey of the asteroid, flying the spacecraft in passes over Bennu’s north pole, equator, and south pole at ranges as close as 4.4 miles (7 km) to better determine the asteroid’s mass. The mission’s scientists and engineers must know the mass of the asteroid in order to design the spacecraft’s insertion into orbit because mass affects the asteroid’s gravitational pull on the spacecraft. Knowing Bennu’s mass will also help the science team understand the asteroid’s structure and composition.
This survey also provides the first opportunity for the OSIRIS-REx Laser Altimeter (OLA), an instrument contributed by the Canadian Space Agency, to make observations, now that the spacecraft is in proximity to Bennu.
The spacecraft’s first orbital insertion is scheduled for Dec. 31, and OSIRIS-REx will remain in orbit until mid-February 2019, when it exits to initiate another series of flybys for the next survey phase. During the first orbital phase, the spacecraft will orbit the asteroid at a range of 0.9 miles (1.4 km) to 1.24 miles (2.0 km) from the center of Bennu — setting new records for the smallest body ever orbited by a spacecraft and the closest orbit of a planetary body by any spacecraft.
Goddard 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 science observation planning and data 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 the Science Mission Directorate in Washington.
For more information about OSIRIS-REx, visit: https://www.nasa.gov/osiris-rex
Image (mentioned), Animation (mentioned), Video (mentioned), Text, Credits: NASA/Dwayne Brown/JoAnna Wendel/Katherine Brown/GSFC/Nancy Jones/University of Arizona/Erin Morton.
Publié par Orbiter.ch à 15:03
NASA - Voyager 1 & 2 Mission patch.
Dec. 10, 2018
Image above: This illustration shows the position of NASA’s Voyager 1 and Voyager 2 probes, outside of the heliosphere, a protective bubble created by the Sun that extends well past the orbit of Pluto. Image Credits: NASA/JPL-Caltech.
For the second time in history, a human-made object has reached the space between the stars. NASA’s Voyager 2 probe now has exited the heliosphere – the protective bubble of particles and magnetic fields created by the Sun.
Members of NASA’s Voyager team will discuss the findings at a news conference at 11 a.m. EST (8 a.m. PST) today at the meeting of the American Geophysical Union (AGU) in Washington. The news conference will stream live on the agency’s website.
NASA’s Voyager 2 Enters Interstellar Space
Comparing data from different instruments aboard the trailblazing spacecraft, mission scientists determined the probe crossed the outer edge of the heliosphere on Nov. 5. This boundary, called the heliopause, is where the tenuous, hot solar wind meets the cold, dense interstellar medium. Its twin, Voyager 1, crossed this boundary in 2012, but Voyager 2 carries a working instrument that will provide first-of-its-kind observations of the nature of this gateway into interstellar space.
Voyager 2 now is slightly more than 11 billion miles (18 billion kilometers) from Earth. Mission operators still can communicate with Voyager 2 as it enters this new phase of its journey, but information – moving at the speed of light – takes about 16.5 hours to travel from the spacecraft to Earth. By comparison, light traveling from the Sun takes about eight minutes to reach Earth.
The most compelling evidence of Voyager 2’s exit from the heliosphere came from its onboard Plasma Science Experiment (PLS), an instrument that stopped working on Voyager 1 in 1980, long before that probe crossed the heliopause. Until recently, the space surrounding Voyager 2 was filled predominantly with plasma flowing out from our Sun. This outflow, called the solar wind, creates a bubble – the heliosphere – that envelopes the planets in our solar system. The PLS uses the electrical current of the plasma to detect the speed, density, temperature, pressure and flux of the solar wind. The PLS aboard Voyager 2 observed a steep decline in the speed of the solar wind particles on Nov. 5. Since that date, the plasma instrument has observed no solar wind flow in the environment around Voyager 2, which makes mission scientists confident the probe has left the heliosphere.
In addition to the plasma data, Voyager’s science team members have seen evidence from three other onboard instruments – the cosmic ray subsystem, the low energy charged particle instrument and the magnetometer – that is consistent with the conclusion that Voyager 2 has crossed the heliopause. Voyager’s team members are eager to continue to study the data from these other onboard instruments to get a clearer picture of the environment through which Voyager 2 is traveling.
Image above: The set of graphs on the left illustrates the drop in electrical current detected in three directions by Voyager 2's plasma science experiment (PLS) to background levels. They are among the key pieces of data that show that Voyager 2 entered interstellar space in November 2018. Image Credits: NASA/JPL-Caltech/MIT.
“There is still a lot to learn about the region of interstellar space immediately beyond the heliopause,” said Ed Stone, Voyager project scientist based at Caltech in Pasadena, California.
Together, the two Voyagers provide a detailed glimpse of how our heliosphere interacts with the constant interstellar wind flowing from beyond. Their observations complement data from NASA’s Interstellar Boundary Explorer (IBEX), a mission that is remotely sensing that boundary. NASA also is preparing an additional mission – the upcoming Interstellar Mapping and Acceleration Probe (IMAP), due to launch in 2024 – to capitalize on the Voyagers’ observations.
“Voyager has a very special place for us in our heliophysics fleet,” said Nicola Fox, director of the Heliophysics Division at NASA Headquarters. “Our studies start at the Sun and extend out to everything the solar wind touches. To have the Voyagers sending back information about the edge of the Sun’s influence gives us an unprecedented glimpse of truly uncharted territory.”
While the probes have left the heliosphere, Voyager 1 and Voyager 2 have not yet left the solar system, and won’t be leaving anytime soon. The boundary of the solar system is considered to be beyond the outer edge of the Oort Cloud, a collection of small objects that are still under the influence of the Sun’s gravity. The width of the Oort Cloud is not known precisely, but it is estimated to begin at about 1,000 astronomical units (AU) from the Sun and to extend to about 100,000 AU. One AU is the distance from the Sun to Earth. It will take about 300 years for Voyager 2 to reach the inner edge of the Oort Cloud and possibly 30,000 years to fly beyond it.
The Voyager probes are powered using heat from the decay of radioactive material, contained in a device called a radioisotope thermal generator (RTG). The power output of the RTGs diminishes by about four watts per year, which means that various parts of the Voyagers, including the cameras on both spacecraft, have been turned off over time to manage power.
“I think we’re all happy and relieved that the Voyager probes have both operated long enough to make it past this milestone,” said Suzanne Dodd, Voyager project manager at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California. “This is what we've all been waiting for. Now we’re looking forward to what we’ll be able to learn from having both probes outside the heliopause.”
Voyager 2 launched in 1977, 16 days before Voyager 1, and both have traveled well beyond their original destinations. The spacecraft were built to last five years and conduct close-up studies of Jupiter and Saturn. However, as the mission continued, additional flybys of the two outermost giant planets, Uranus and Neptune, proved possible. As the spacecraft flew across the solar system, remote-control reprogramming was used to endow the Voyagers with greater capabilities than they possessed when they left Earth. Their two-planet mission became a four-planet mission. Their five-year lifespans have stretched to 41 years, making Voyager 2 NASA’s longest running mission.
The Voyager story has impacted not only generations of current and future scientists and engineers, but also Earth's culture, including film, art and music. Each spacecraft carries a Golden Record of Earth sounds, pictures and messages. Since the spacecraft could last billions of years, these circular time capsules could one day be the only traces of human civilization.
Voyager’s mission controllers communicate with the probes using NASA’s Deep Space Network (DSN), a global system for communicating with interplanetary spacecraft. The DSN consists of three clusters of antennas in Goldstone, California; Madrid, Spain; and Canberra, Australia.
The Voyager Interstellar Mission is a part of NASA’s Heliophysics System Observatory, sponsored by the Heliophysics Division of NASA’s Science Mission Directorate in Washington. JPL built and operates the twin Voyager spacecraft. NASA’s DSN, managed by JPL, is an international network of antennas that supports interplanetary spacecraft missions and radio and radar astronomy observations for the exploration of the solar system and the universe. The network also supports selected Earth-orbiting missions. The Commonwealth Scientific and Industrial Research Organisation, Australia’s national science agency, operates both the Canberra Deep Space Communication Complex, part of the DSN, and the Parkes Observatory, which NASA has been using to downlink data from Voyager 2 since Nov. 8.
NASA's Voyager 1 Explores Final Frontier of Our 'Solar Bubble'
Interstellar Boundary Explorer (IBEX): https://www.nasa.gov/mission_pages/ibex/index.html
Interstellar Mapping and Acceleration Probe (IMAP): https://www.nasa.gov/press-release/nasa-selects-mission-to-study-solar-wind-boundary-of-outer-solar-system
Deep Space Network (DSN): https://www.nasa.gov/directorates/heo/scan/services/networks/dsn
For more information about the Voyager mission, visit: https://www.nasa.gov/voyager
More information about NASA’s Heliophysics missions is available online at: https://www.nasa.gov/sunearth
Images (mentioned), Animations, Video, Text, Credits: NASA/Dwayne Brown/Karen Fox/Sean Potter/JPL/Calla Cofield.
Best regards, Orbiter.ch
Publié par Orbiter.ch à 14:51