jeudi 15 février 2018
Last NASA Communications Satellite of its Kind Joins Fleet
NASA - TDRS Mission logo.
Feb. 15, 2018
NASA has begun operating the last satellite of its kind in the network that provides communications and tracking services to more than 40 NASA missions, including critical, real-time communication with the International Space Station. Following its August launch and a five-month period of in-orbit testing, the third-generation Tracking and Data Relay Satellite (TDRS), referred to as TDRS-M until this important milestone, was renamed TDRS-13, becoming the tenth operational satellite in the geosynchronous, space-based fleet.
“With TDRS-13’s successful acceptance into the network, the fleet is fully replenished and set to continue carrying out its important mission through the mid-2020s,” said Badri Younes, NASA’s deputy associate administrator for Space Communications and Navigation at NASA Headquarters in Washington. “Now, we have begun focusing on the next generation of near-Earth communications relay capabilities.”
Image above: An artist concept of TDRS-M, now named TDRS-13. Image Credits: NASA's Goddard Space Flight Center.
The 10 TDRS spacecraft comprise the space-based portion of the Space Network, relaying signals from low-Earth-orbiting missions with nearly 100 percent coverage.
“The acceptance of this final third-generation TDRS into the Space Network is the result of many years of dedication and hard work by the TDRS team,” said Dave Littmann, the TDRS project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “As a result, critical space communication and tracking services that enable NASA human spaceflight and scientific discovery will continue well into the next decade.”
TDRS-13 launched on Aug. 18, 2017, aboard a United Launch Alliance Atlas V rocket from Cape Canaveral Air Force Station in Florida. Built by Boeing in El Segundo, California, TDRS-13 and its nearly identical third-generation sister spacecraft are performing well. TDRS-K and -L launched in 2013 and 2014, respectively.
NASA established the TDRS project in 1973, and the first satellite launched 10 years later, providing NASA an exponential increase in data rates and contact time communicating with the space shuttle and other orbiting spacecraft, such as the Hubble Space Telescope. Since then, NASA has continued to expand the TDRS constellation and advance the spacecraft capabilities.
Image above: TDRS-M, now named TDRS-13, launched on Aug. 18, 2017, from Cape Canaveral Air Force Station in Florida. Following a period of in-orbit testing, the spacecraft has been accepted into NASA’s Space Network. Image Credits: NASA Kennedy/Tony Gray and Sandra Joseph.
“NASA looks forward to the future, developing even better ways to meet missions’ communications needs,” said Younes. “We will leverage NASA’s success in optical communications and other innovative technologies, as well as significantly increase our partnership with industry, as we envision a shift to increased reliance on commercial networks for most, if not all, of our communications needs in the near-Earth environment.”
Goddard is home to the TDRS project, which is responsible for the development and launch of these communication satellites. Boeing, headquartered in Chicago, Illinois, is the private contractor for the third-generation TDRS spacecraft. TDRS is the space element of NASA’s Space Network, providing the critical communication and navigation lifeline for NASA missions. NASA’s Space Communications and Navigation (SCaN) program, part of the Human Exploration and Operations Mission Directorate at the agency’s Headquarters in Washington, is responsible for NASA’s Space Network.
For more information about NASA’s TDRS satellites, visit: https://www.nasa.gov/tdrs
For more information about SCaN, visit: https://www.nasa.gov/SCaN
Space Network: https://www.nasa.gov/directorates/heo/scan/services/networks/sn
Images (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center, by Ashley Hume.
Greetings, Orbiter.ch
Station Prepping for Spacewalk After New Cargo Ship Arrives
ISS - Expedition 54 Mission patch.
February 15, 2018
International Space Station (ISS). Animation Credit: NASA
The Expedition 54 crew is getting ready for a spacewalk Friday morning and beginning the work to unload a newly-arrived cargo delivery.
Astronauts Mark Vande Hei and Norishige Kanai are completing their spacewalk reviews and readying their spacesuits and tools ahead of Friday morning’s excursion. The duo is scheduled to turn their spacesuits batteries on to internal power at 7:10 a.m. EST signifying the start of a planned six and a half hour spacewalk.
The spacewalkers will complete the transfer of a pair of older robotic hands, or Latching End Effectors (LEEs), that were once attached to the Canadarm2 robotic arm. One LEE will be transferred inside the Quest airlock while the other will be attached to the mobile base system. NASA TV will start its live coverage of the spacewalk activities beginning at 5:30 a.m.
Image above: NASA astronaut Mark Vande Hei is pictured during a spacewalk that took place Jan. 23, 2018, to begin maintenance work on the Canadarm2 robotic arm. Image Credit: NASA.
Cosmonauts Alexander Misurkin and Anton Shkaplerov opened the hatch to a new Progress cargo craft that arrived today at 5:38 a.m. The duo will start the work to offload a little over three tons of food, fuel and supplies from the resupply ship that will stay docked to the Zvezda service module until March.
Related links:
NASA TV: https://www.nasa.gov/multimedia/nasatv/index.html
Expedition 54: https://www.nasa.gov/mission_pages/station/expeditions/expedition54/index.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), Text, Credits: NASA/Mark Garcia.
Best regards, Orbiter.ch
Hubble Sees Neptune's Mysterious Shrinking Storm
NASA - Hubble Space Telescope patch.
Feb. 15, 2018
Three billion miles away on the farthest known major planet in our solar system, an ominous, dark storm – once big enough to stretch across the Atlantic Ocean from Boston to Portugal – is shrinking out of existence as seen in pictures of Neptune taken by NASA’s Hubble Space Telescope.
Immense dark storms on Neptune were first discovered in the late 1980s by NASA’s Voyager 2 spacecraft. Since then, only Hubble has had the sharpness in blue light to track these elusive features that have played a game of peek-a-boo over the years. Hubble found two dark storms that appeared in the mid-1990s and then vanished. This latest storm was first seen in 2015, but is now shrinking.
Hubble Watches Neptune's Dark Storm Die
Video above: For the first time, NASA's Hubble Space Telescope has captured time-lapse images of a large, dark storm on Neptune shrinking out of existence.
Credits: NASA Goddard's Scientific Visualization Studio.
Like Jupiter’s Great Red Spot (GRS), the storm swirls in an anti-cyclonic direction and is dredging up material from deep inside the ice giant planet’s atmosphere. The elusive feature gives astronomers a unique opportunity to study Neptune’s deep winds, which can’t be directly measured.
The dark spot material may be hydrogen sulfide, with the pungent smell of rotten eggs. Joshua Tollefson from the University of California at Berkeley explained, “The particles themselves are still highly reflective; they are just slightly darker than the particles in the surrounding atmosphere.”
Unlike Jupiter’s GRS, which has been visible for at least 200 years, Neptune’s dark vortices only last a few years. This is the first one that actually has been photographed as it is dying.
“We have no evidence of how these vortices are formed or how fast they rotate,” said Agustín Sánchez-Lavega from the University of the Basque Country in Spain. “It is most likely that they arise from an instability in the sheared eastward and westward winds.”
Image above: This series of Hubble Space Telescope images taken over 2 years tracks the demise of a giant dark vortex on the planet Neptune. The oval-shaped spot has shrunk from 3,100 miles across its long axis to 2,300 miles across, over the Hubble observation period. Image Credits: NASA, ESA, and M.H. Wong and A.I. Hsu (UC Berkeley).
The dark vortex is behaving differently from what planet-watchers predicted. “It looks like we’re capturing the demise of this dark vortex, and it’s different from what well-known studies led us to expect,” said Michael H. Wong of the University of California at Berkeley, referring to work by Ray LeBeau (now at St. Louis University) and Tim Dowling’s team at the University of Louisville. “Their dynamical simulations said that anticyclones under Neptune’s wind shear would probably drift toward the equator. We thought that once the vortex got too close to the equator, it would break up and perhaps create a spectacular outburst of cloud activity.”
But the dark spot, which was first seen at mid-southern latitudes, has apparently faded away rather than going out with a bang. That may be related to the surprising direction of its measured drift: toward the south pole, instead of northward toward the equator. Unlike Jupiter’s GRS, the Neptune spot is not as tightly constrained by numerous alternating wind jets (seen as bands in Jupiter’s atmosphere). Neptune seems to only have three broad jets: a westward one at the equator, and eastward ones around the north and south poles. The vortex should be free to change traffic lanes and cruise anywhere in between the jets.
“No facilities other than Hubble and Voyager have observed these vortices. For now, only Hubble can provide the data we need to understand how common or rare these fascinating neptunian weather systems may be,” said Wong.
The first images of the dark vortex are from the Outer Planet Atmospheres Legacy (OPAL) program, a long-term Hubble project that annually captures global maps of our solar system’s four outer planets. Only Hubble has the unique capability to probe these worlds in ultraviolet light, which yields important information not available to other present-day telescopes. Additional data, from a Hubble program targeting the dark vortex, are from an international team including Wong, Tollefson, Sánchez-Lavega, Andrew Hsu, Imke de Pater, Amy Simon, Ricardo Hueso, Lawrence Sromovsky, Patrick Fry, Statia Luszcz-Cook, Heidi Hammel, Marc Delcroix, Katherine de Kleer, Glenn Orton, and Christoph Baranec.
Wong’s paper appears online in the Astronomical Journal on Feb. 15, 2018.
The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.
For additional imagery, visit: http://hubblesite.org/news_release/news/2018-08
For NASA’s Hubble web page, visit: http://www.nasa.gov/hubble
Image (mentioned), Text, Credits: NASA/Karl Hille/Space Telescope Science Institute/Ray Villard.
Best regards, Orbiter.ch
Supermassive Black Holes Are Outgrowing Their Galaxies
NASA - Chandra X-ray Observatory patch.
Feb. 15, 2018
The biggest black holes in the Universe are growing faster than the rate of stars being formed in their galaxies, according to two new studies using data from NASA’s Chandra X-ray Observatory and other telescopes.
Over many years, astronomers have gathered data on the formation of stars in galaxies and the growth of supermassive black holes (that is, those with millions or billions the mass of the Sun) in their centers. These data suggested that the black holes and the stars in their host galaxies grow in tandem with each other.
Now, findings from two independent groups of researchers indicate that the black holes in massive galaxies have grown much faster than in the less massive ones.
“We are trying to reconstruct a race that started billions of years ago,” said Guang Yang of Penn State who led one of the two studies. “We are using extraordinary data taken from different telescopes to figure out how this cosmic competition unfolded.”
Image above: In this graphic an image from the Chandra Deep Field-South is shown. The Chandra image (blue) is the deepest ever obtained in X-rays. It has been combined with an optical and infrared image from the Hubble Space Telescope (HST), colored red, green, and blue. Each Chandra source is produced by hot gas falling towards a supermassive black hole in the center of the host galaxy, as depicted in the artist’s illustration. Image Credits: NASA/CXC/Penn. State/G. Yang et al and NASA/CXC/ICE/M. Mezcua et al.; Optical: NASA/STScI; Illustration: NASA/CXC/A. Jubett.
Using large amounts of data from NASA's Chandra X-ray Observatory, the Hubble Space Telescope and other observatories, Yang and his colleagues studied the growth rate of black holes in galaxies at distances of 4.3 to 12.2 billion light years from Earth. The X-ray data included the Chandra Deep Field-South & North and the COSMOS-Legacy surveys.
The scientists calculated the ratio between a supermassive black hole's growth rate and the growth rate of stars in its host galaxy. A common idea is that this ratio is approximately constant for all galaxies.
Instead, Yang and colleagues found that this ratio is much higher for more massive galaxies. For galaxies containing about 100 billion solar masses worth of stars, the ratio is about ten times higher than it is for galaxies containing about 10 billion solar masses worth of stars.
“An obvious question is why?” said co-author Niel Brandt, also of Penn State. “Maybe massive galaxies are more effective at feeding cold gas to their central supermassive black holes than less massive ones.”
Another group of scientists independently found evidence that the most massive black holes’ growth has outstripped that of stars in their host galaxies. Mar Mezcua, of the Institut of Space Sciences in Spain, and her colleagues studied black holes in some of the brightest and most massive galaxies in the Universe. They studied 72 galaxies located at the center of galaxy clusters at distances ranging up to about 3.5 billion light years from Earth. The study used X-ray data from Chandra and radio data from the Australia Telescope Compact Array, the Karl G. Jansky Very Large Array and Very Long Baseline Array.
Chandra X-ray Observatory. Image Credits: NASA/CXC
Mezcua and her colleagues estimated the masses of black holes in these galaxy clusters by using a well-known relationship that connects the mass of a black hole to the X-ray and radio emission associated with the black hole. The black hole masses were found to be about ten times larger than masses estimated by another method using the assumption that the black holes and galaxies grew in tandem.
“We found black holes that are far bigger than we expected,” said Mezcua. “Maybe they got a head start in this race to grow, or maybe they’ve had an edge in speed of growth that’s lasted billions of years.”
The researchers found that almost half of the black holes in their sample had masses estimated to be at least 10 billion times the mass of the Sun. This places them in an extreme weight category that some astronomers call “ultramassive” black holes.
"We know that black holes are extreme objects,” said co-author J. Hlavacek-Larrondo of the University of Montreal, “so it may not come as a surprise that the most extreme examples of them would break the rules we thought they should follow."
The work by Mezcua et al. was published in the February 2018 issue of Monthly Notices of the Royal Astronomical Society (MNRAS) and is available online (https://arxiv.org/abs/1710.10268). The paper by Yang et al. has been accepted and will appear in the April 2018 issue of the MNRAS (available online: https://arxiv.org/abs/1710.09399).
NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.
Read More from NASA's Chandra X-ray Observatory: http://chandra.harvard.edu/photo/2018/cdfs_bh/
For more Chandra images, multimedia and related materials, visit: http://www.nasa.gov/chandra
Images (mentioned), Text, Credits: NASA/Lee Mohon/Chandra X-ray Center/Megan Watzke/Marshall Space Flight Center/Molly Porter.
Greetings, Orbiter.ch
Swarm details energetic coupling
ESA - SWARM Mission logo.
15 February 2018
The Sun bathes our planet in the light and heat it needs to sustain life, but it also bombards us with dangerous charged particles in solar wind. Our magnetic field largely shields from this onslaught, but like many a relationship, it’s somewhat complicated. Thanks to ESA’s Swarm mission the nature of this Earth–Sun coupling has been revealed in more detail than ever before.
Earth's protective shield
Earth’s magnetic field is like a huge bubble, protecting us from cosmic radiation and charged particles carried by powerful winds that escape the Sun’s gravitational pull and sweep across the Solar System.
The trio of Swarm satellites were launched in 2013 to improve our understanding of how the field is generated and how it protects us from this barrage of charged particles.
Since our magnetic field is generated mainly by an ocean of liquid iron that makes up the planet’s outer core, it resembles a bar magnet with field lines emerging from near the poles.
The field is highly conductive and carries charged particles that flow along these field lines, giving rise to field-aligned currents.
Aurora borealis
Carrying up to 1 TW of electrical power – about six times the amount of energy produced every year by wind turbines in Europe – these currents are the dominant form of energy transfer between the magnetosphere and ionosphere.
The shimmering green and purple light displays of the auroras in the skies above the polar regions are a visible manifestation of energy and particles travelling along magnetic field lines.
The theory about the exchange and momentum between solar wind and our magnetic field actually goes back more than 100 years, and more recently the Active Magnetosphere and Planetary Electrodynamics Response Experiment satellite network has allowed scientists to study large-scale field-aligned currents.
However, the Swarm mission is leading to exciting new wave of discoveries. A new paper explores the dynamics of this energetic coupling across different spatial scales – and finds that it’s all in the detail.
Ryan McGranaghan from NASA’s Jet Propulsion Laboratory said, “We have a good understanding of how these currents exchange energy between the ionosphere and the magnetosphere at large scales so we assumed that smaller-scale currents behaved in the same way, but carried proportionally less energy.”
“Swarm has allowed us to effectively zoom in on these smaller currents and we see that, under certain conditions, this is not the case.
“Our findings show that these smaller currents carry significant energy and that their relationship with the larger currents is very complex. Moreover, large and small currents affect the magnetosphere–ionosphere differently.”
Our star’s turbulent surface
Colin Forsyth from University College London noted, “Since electric currents around Earth can interfere with navigation and telecommunication systems, this is an important discovery.
“It also gives us a greater understanding of how the Sun and Earth are linked and how this coupling can ultimately add energy to our atmosphere.
“This new knowledge can be used to improve models so that we can better understand, and therefore, ultimately, prepare for the potential consequences of solar storms.”
ESA’s Swarm mission manager, Rune Floberghagen, added, “Since the beginning of the mission we have carried out projects to address the energy exchange between the magnetosphere, ionosphere and the thermosphere.
Swarm constellation
"But what we are witnessing now is nothing short of a complete overhaul of the understanding of how Earth responds to and interacts with output from the Sun.
“In fact, this scientific investigation is becoming a fundamental pillar for the extended Swarm mission, precisely because it is breaking new ground and at the same time has strong societal relevance. We now wish to explore this potential of Swarm to the fullest.”
Related links:
Active Magnetosphere and Planetary Electrodynamics Response Experiment: http://ampere.jhuapl.edu/
Journal of Geophysical Research:
A comprehensive Analysis of Multiscale Field-Aligned Currents: http://onlinelibrary.wiley.com/doi/10.1002/2017JA024742/pdf
ESA's Swarm: http://www.esa.int/Our_Activities/Observing_the_Earth/Swarm
Images, Text, Credits: ESA/ATG medialab/Sherwin Calaluan/DTU Space/ROB.
Greetings, Orbiter.ch
A Lonely Beauty
ESA - Hubble Space Telescope logo.
15 February 2018
Multi-filter image of NGC 3344
Beauty, grace, mystery — this magnificent spiral galaxy has all the qualities of a perfect galactic Valentine. Captured by the NASA/ESA Hubble Space Telescope, the galaxy NGC 3344 presents itself face-on, allowing astronomers a detailed look at its intricate and elegant structure. And Hubble’s ability to observe objects over a wide range of different wavelengths reveals features that would otherwise remain invisible.
Spiral galaxies are some of the most spectacular sights in the sky, but to an observer they do not all look the same. Some are seen edge-on, giving astronomers an excellent idea of the galaxy’s vertical structure; others are seen at an angle, providing a hint of the size and structure of the spiral arms; while others are seen face-on, showcasing their arms and bright core in all their beauty.
Wide-field image of NGC 3344 (ground-based image)
Approximately 20 million light-years away in the constellation of Leo Minor (the Lion Cub), NGC 3344 is seen from a breathtaking face-on perspective. Half the size of the Milky Way, it is classified as a weakly barred spiral galaxy. The central bar is just visible in this image, taken with Hubble’s Wide Field Camera 3: an elongated lane of stars, trailing through the nucleus of the galaxy. Astronomers estimate that two-thirds of all spiral galaxies are barred, including our own Milky Way.
Hubble’s capacity to observe celestial objects in different wavelengths allows us to see more than just the spiral arms sweeping out loosely around the centre in a gorgeous whorl. This image is a composite of images taken through different filters, ranging from the near ultraviolet, to the optical and the near-infrared. Together they show a more complete picture of the galaxy than the human eye alone could possibly see.
Zoom-in on NGC 3344
The swirling spiral arms are the birthplace of new stars, whose high temperatures make them shine blue, resulting in them being easily identifiable in this image. Clouds of dust and gas distributed through the spiral arms — glowing red in this image — are reservoirs of material for even more stars. The bright jewel-like stars on the left of the picture, however, are much closer to Earth — they belong to our own galaxy and just happened to photobomb this Hubble image.
The different colours of NGC 3344
While its face-on orientation reveals much about NGC 3344’s detailed structure, this galaxy is still enigmatic; astronomers have noticed that some of its outer stars are moving in a strange way. Often, the high concentration of stars in the centre of a galaxy can affect the movements of the outer stars, but this does not seem to be the case in NGC 3344. Astronomers suspect that these weirdly behaving outer stars may actually have been stolen from another galaxy, after a close encounter that took place long ago.
Pan on NGC 3344
The location of NGC 3344 is also intriguing. Our galaxy is part of the Local Group, which is made up of approximately 40 other galaxies, with the Andromeda Galaxy being the largest member. But NGC 3344 is not part of a local galactic neighbourhood like we are. It is actually part of a small spur that leads off the larger Virgo Supercluster — a gargantuan collection of several thousand galaxies.
But it stands out from these thousands of galaxies because of its beauty, which highlights to us the elegance of the Universe.
Hubble Space Telescope. Animation Credits: NASA/ESA
More information:
The Hubble Space Telescope is a project of international cooperation between ESA and NASA.
Links:
Hubblecast 107: Decoding the colours of NGC 3344: https://www.spacetelescope.org/videos/heic1803a/
Images of Hubble: http://www.spacetelescope.org/images/archive/category/spacecraft/
NGC 3344 observed in 2012: http://spacetelescope.org/images/potw1242a/
Hubble’s Wide Field Camera 3: https://www.spacetelescope.org/about/general/instruments/wfc3/
Images, Videos, Text, Credits: NASA, ESA.
Best regards, Orbiter.ch
Russian Resupply Ship Delivers Three Tons of Cargo
ROSCOSMOS - Russian Vehicles patch.
February 15, 2018
Image above: The Progress 69 resupply ship is pictured just moments from docking to the space station. Image Credit: NASA TV.
Traveling about 250 miles over the east of the Philippines, the Progress 69 Russian cargo spacecraft docked to the aft end of the service module of the International Space Station at 5:38 a.m. EST.
Progress MS-08 docking to the ISS
The Progress MS-08 spacecraft automatically docked to the aft port of the Zvezda service module of the International Space Station on on 15 February 2018, at 10:38 UTC. ISS Progress 69 mission was launched by a Soyuz-2.1a launch vehicle on 13 February 2018, at 08:13 UTC (14:13 local time) and will remain at the orbiting laboratory until late August.
For more information about the space station and its crew, visit: https://www.nasa.gov/station.
Related links:
Progress 69 (69P): https://go.nasa.gov/2nX3x4W
Expedition 54: https://www.nasa.gov/mission_pages/station/expeditions/expedition54/index.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, Text, Credits: NASA/Mark Garcia/NASA TV/SciNews.
Best regards, Orbiter.ch
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