mardi 19 juin 2018

Deep Space Navigation: Tool Tested as Emergency Navigation Device












ISS - International Space Station logo.

June 19, 2018

A tool that has helped guide sailors across oceans for centuries is now being tested aboard the International Space Station as a potential emergency navigation tool for guiding future spacecraft across the cosmos. The Sextant Navigation investigation tests use of a hand-held sextant aboard the space station.


Image above: NASA astronaut Alexander Gerst learns how to use a sextant. “I learned how to navigate after the stars using a sextant,” said Gerst. “It’s actually a test for a backup nav method for #Orion & future deep space missions.” Image Credit: NASA.

Sextants have a telescope-like optical sight to take precise angle measurements between pairs of stars from land or sea, enabling navigation without computer assistance. NASA’s Gemini missions conducted the first sextant sightings from a spacecraft, and designers built a sextant into Apollo vehicles as a navigation backup in the event the crew lost communications from their spacecraft. Jim Lovell demonstrated on Apollo 8 that sextant navigation could return a space vehicle home. Astronauts conducted additional sextant experiments on Skylab.

“The basic concepts are very similar to how it would be used on Earth,” says principal investigator Greg Holt. “But particular challenges on a spacecraft are the logistics; you need to be able to take a stable sighting through a window. We’re asking the crew to evaluate some ideas we have on how to accomplish that and to give us feedback and perhaps new ideas for how to get a stable, clean sight. That’s something we just can’t test on the ground.”


Image above: Jim Lovell demonstrated on Apollo 8 that sextant navigation could return a space vehicle home. Image Credit: NASA.

The investigation tests specific techniques for using a sextant for emergency navigation on space vehicles such as Orion. With the right techniques, crews can use the tool to navigate their way home based on angles between the moon or planets and stars, even if communications and computers become compromised.

“No need to reinvent the wheel when it comes to celestial navigation,” Holt says. “We want a robust, mechanical back-up with as few parts and as little need for power as possible to get you back home safely. Now that we plan to go farther into space than ever before, crews need the capability to navigate autonomously in the event of lost communication with the ground.”

Early explorers put a lot of effort into refining sextants to be compact and relatively easy to use. The tool’s operational simplicity and spaceflight heritage make it a good candidate for further investigation as backup navigation.

Related links:

Sextant Navigation: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7646

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), Text, Credits: NASA/Michael Johnson/JSC/International Space Station Program Science Office/Melissa Gaskill.

Greetings, Orbiter.ch

lundi 18 juin 2018

Investigation Tests BEST Method of DNA and RNA Sequencing










NASA - Genes in Space logo.

June 18, 2018

Much of present-day science focuses on exploring the molecular world. A primary tool is DNA sequencing, performed for the first time on the International Space Station in August 2016.

International Space Station (ISS). Animation Credit: NASA

An investigation now aboard the space station, Biomolecule Extraction and Sequencing Technology (BEST), seeks to advance use of sequencing in space in three ways: identifying microbes aboard the space station that current methods cannot detect, assessing microbial mutations in the genome because of spaceflight and performing direct RNA sequencing. All use compact tools, including the MinION miniature sequencer, already proven to work onboard the space station.

The remoteness and constrained resources of living in space require simple but effective processes and procedures to monitor the presence of microbial life, some of which might be harmful. A previous investigation, Genes in Space 3, performed in-flight identification of bacteria on the station for the first time. BEST takes that one step farther, says principal investigator Sarah Wallace, identifying unknown microbial organisms using a swab-to-sequencer process rather than a traditional culture-based technique. “That way, we can identify microbes that cannot be detected using traditional culturing methods, and we aren’t increasing the number of potential pathogens that might be present on the station,” Wallace explained.


Image above: Biomolecule Extraction and Sequencing Technology (BEST) seeks to advance use of sequencing in space via three objectives: identifying microbes aboard the space station that current methods cannot detect, assessing microbial mutations in the genome because of spaceflight, and performing direct RNA sequencing. Pictured above are Sarah Stahl and Christian Castro, microbiologists on the project. Image Credit: NASA.

For the second objective, researchers plan to compare full genome sequences from multiple generations of a model organism grown on the space station against those from the same organism grown in parallel on Earth. “This can provide insight into mutation rates in low-Earth orbit,” said project manager Kristen John.

Finally, BEST demonstrates the process of direct RNA sequencing, which opens new avenues for in-flight research. Researchers found that organisms respond to spaceflight by making transcriptomic changes, changes in RNA or gene expression. Sequencing RNA defines what genes are turned on and off, which is important for understanding how life adapts to spaceflight.

“Because the MinION detects changes in current, it can directly sequence RNA as well as DNA,” said co-investigator Aaron Burton. “With most other platforms, you first have to convert RNA to DNA, and this additional processing could bias your data, causing you to miss what’s really going on. Direct RNA sequencing results in near real-time gene expression data.”


Image above: The MinION miniature sequencer and the miniPCR, both compact tools used aboard the space station. Image Credit: NASA.

“With small modifications to our process, you can pretty much do any type of sequencing on the station,” said Wallace. “Until now, we had to bring samples back to the ground to see these changes. We know gene expression changes, but freezing a sample and bringing it back to the ground could result in alterations not caused by the spaceflight environment. If we could look at it while on the station, it might look very different. There is so much to be gained from that real-time snapshot of gene expression.”

The investigation’s DNA and RNA sequencing components provide important information about the station’s microbial occupants, including which organisms are present and how they respond to the spaceflight environment -- knowledge that will help protect humans during future space exploration. The validation of direct RNA sequencing has the potential to be a game-changer for research into crew health by eliminating the need for conversion and bias it may introduce. Knowledge gained from BEST also can be implemented to provide new ways to monitor the presence of microbes in remote locations on Earth.

Related links:

Biomolecule Extraction and Sequencing Technology (BEST): https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7687

Genes in Space 3: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7448

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

Animation (mentioned), Images (mentioned), Text, Credits: NASA/Michael Johnson/JSC/International Space Station Program Science Office/Melissa Gaskill.

Greetings, Orbiter.ch

55 Years ago the first woman in space












ROSCOSMOS - Vostok 6 Mission patch.

June 18, 2018

55 years ago Valentina Tereshkova escaped to the stars and herself became a bright star!  The first "Seagull" of Soviet cosmonautics (such a call-sign was invented for Tereshkova by SP Korolev) is still the only woman of the planet who made a single space flight.

Valentina Tereshkova entering inside Vostok 6 spacecraft

The first woman in space was former civilian parachutist Valentina Tereshkova, born 6 March 1937, is a retired Russian cosmonaut, engineer, and politician. She is the first woman to have flown in space, having been selected from more than 400 applicants and five finalists to pilot Vostok 6 on 16 June 1963. In order to join the Cosmonaut Corps, Tereshkova was honorarily inducted into the Soviet Air Force and thus she also became the first civilian to fly in space.

55 years since the flight of Valentina Tereshkova

who entered orbit on June 16, 1963, aboard the Soviet mission Vostok 6. The chief Soviet spacecraft designer, Sergey Korolyov, conceived of the idea to recruit a female cosmonaut corps and launch two women concurrently on Vostok 5/6. However, his plan was changed to launch a male first in Vostok 5, followed shortly afterward by Tereshkova. Khrushchev personally spoke to Tereshkova by radio during her flight.

Valentina Tereshkova

On November 3, 1963, Tereshkova married fellow cosmonaut Andrian Nikolayev, who had previously flown on Vostok 3. On June 8, 1964, she gave birth to the first child conceived by two space travelers.  The second woman to fly to space was aviator Svetlana Savitskaya, aboard Soyuz T-7 on August 18, 1982.

More information:

Chronicle of soviet-russian space program: http://en.roscosmos.ru/174/

Valentina Tereshkova on Wikipedia:  https://en.wikipedia.org/wiki/Valentina_Tereshkova

Images, Video, Text, Credits: ROSCOSMOS/Wikipedia.

Best regards, Orbiter.ch

Star shredded by rare breed of black hole












ESA - XMM-Newton Mission patch.

18 June 2018

ESA’s XMM-Newton observatory has discovered the best-ever candidate for a very rare and elusive type of cosmic phenomenon: a medium-weight black hole in the process of tearing apart and feasting on a nearby star.

There are various types of black hole lurking throughout the Universe: massive stars create stellar-mass black holes when they die, while galaxies host supermassive black holes at their centres, with masses equivalent to millions or billions of Suns.

Black hole candidate and host galaxy

Lying between these extremes is a more retiring member of the black hole family: intermediate-mass black holes. Thought to be seeds that will eventually grow to become supermassive, these black holes are especially elusive, and thus very few robust candidates have ever been found.

Now, a team of researchers using data from ESA’s XMM-Newton X-ray space observatory, as well as NASA’s Chandra X-Ray Observatory and Swift X-Ray Telescope, has found a rare telltale sign of activity. They detected an enormous flare of radiation in the outskirts of a distant galaxy, thrown off as a star passed too close to a black hole and was subsequently devoured.

“This is incredibly exciting: this type of black hole hasn’t been spotted so clearly before,” says lead scientist Dacheng Lin of the University of New Hampshire, USA.

“A few candidates have been found, but on the whole they’re extremely rare and very sought after. This is the best intermediate-mass black hole candidate observed so far.”

This breed of black hole is thought to form in various ways. One formation scenario is the runaway merger of massive stars lying within dense star clusters, making the centres of these clusters one of the best places to hunt for them. However, by the time such black holes have formed, these sites tend to be devoid of gas, leaving the black holes with no material to consume and thus little radiation to emit – which in turn makes them extremely difficult to spot.

XMM-Newton view

“One of the few methods we can use to try to find an intermediate-mass black hole is to wait for a star to pass close to it and become disrupted — this essentially ‘activates’ the black hole’s appetite again and prompts it to emit a flare that we can observe,” adds Lin.

“This kind of event has only been clearly seen at the centre of a galaxy before, not at the outer edges.”

Lin and colleagues sifted through data from XMM-Newton to find the candidate. They identified it in observations of a large galaxy some 740 million light-years away, taken in 2006 and 2009 as part of a galaxy survey, and in additional data from Chandra (2006 and 2016) and Swift (2014).

“We also looked at images of the galaxy taken by a whole host of other telescopes, to see what the emission looked like optically,” says co-author Jay Strader of Michigan State University, USA.

“We spotted the source flaring in brightness in two images from 2005 — it appeared far bluer and brighter than it had just a few years previously. By comparing all the data we determined that the unfortunate star was likely disrupted in October 2003 in our time, and produced a burst of energy that decayed over the following 10 years or so.”

The scientists believe that the star was disrupted and torn apart by a black hole with a mass of around fifty thousand times that of the Sun.

Such star-triggered outbursts are expected to only happen rarely from this type of black hole, so this discovery suggests that there could be many more lurking in a dormant state in galaxy peripheries across the local Universe.

“This candidate was discovered via an intensive search of XMM-Newton’s X-ray Source Catalogue, which is filled with high-quality data covering large areas of sky, essential for determining how large the black hole was and what happened to cause the observed burst of radiation,” says Norbert Schartel, ESA Project Scientist for XMM-Newton.

XMM-Newton

“The XMM-Newton X-ray Source Catalogue is presently the largest catalogue of this type, containing more than half a million sources: exotic objects like the one discovered in our study are still hidden there and waiting to be discovered through intensive data mining,” adds co-author Natalie Webb, director of the XMM-Newton Survey Science Center at theResearch Institute in Astrophysics and Planetology (IRAP) in Toulouse, France.

“Learning more about these objects and associated phenomena is key to our understanding of black holes. Our models are currently akin to a scenario in which an alien civilisation observes Earth and spots grandparents dropping their grandchildren at pre-school: they might assume that there’s something intermediate to fit their model of a human lifespan, but without observing that link, there’s no way to know for sure. This finding is incredibly important, and shows that the discovery method employed here is a good one to use,” concludes Norbert.

Notes for Editors:

"A luminous X-ray outburst from an intermediate-mass black hole in an off-centre star cluster", by D. Lin et al, is published in Nature Astronomy. DOI: 10.1038/s41550-018-0493-1

The study used data from ESA’s XMM-Newton X-ray space observatory, NASA’s Chandra X-Ray Observatory, and NASA’s Swift X-Ray Telescope, and additional images from the Canada-France-Hawaii Telescope, the NASA/ESA Hubble Space Telescope, NAOJ’s SubaruTelescope, the Southern Astrophysical Research (SOAR) Telescope, and the Gemini Observatory.

The galaxy is named 6dFGS gJ215022.2-055059, while the X-ray source inferred to contain the IMBH is named 3XMM J215022.4−055108. 

Related links:

Nature Astronomy: https://www.nature.com/articles/s41550-018-0493-1

XMM-Newton: http://sci.esa.int/xmm-newton/

XMM-Newton overview: http://www.esa.int/Our_Activities/Space_Science/XMM-Newton_overview

XMM-Newton image gallery: http://xmm.esac.esa.int/external/xmm_science/gallery/public/index.php

XMM-Newton in-depth: http://sci.esa.int/science-e/www/area/index.cfm?fareaid=23

Images, Text, Credits: ESA/Markus Bauer/XMM-Newton/Norbert Schartel/Natalie Webb/Michigan State University/Jay Strader/University of New Hampshire/Dacheng Lin/Optical: NASA/ESA/Hubble/STScI; X-ray: NASA/CXC/UNH/D. Lin et al./ESA/XMM-Newton; D. Lin et al (University of New Hampshire, USA). Acknowledgement: NASA/CXC.

Best regards, Orbiter.ch

Dark and Stormy Jupiter












NASA - JUNO Mission logo.

June 18, 2018


This image captures the intensity of the jets and vortices in Jupiter’s North North Temperate Belt.

NASA’s Juno spacecraft took this color-enhanced image at 10:31 p.m. PDT on May 23, 2018 (1:31 a.m. EDT on May 24), as Juno performed its 13th close flyby of Jupiter. At the time, the spacecraft was about 4,900 miles (7,900 kilometers) from the tops of the clouds of the gas giant planet at a northern latitude of about 41 degrees. The view is oriented with south on Jupiter toward upper left and north toward lower right.

The North North Temperate Belt is the prominent reddish-orange band left of center. It rotates in the same direction as the planet and is predominantly cyclonic, which in the northern hemisphere means its features spin in a counter-clockwise direction. Within the belt are two gray-colored anticyclones. 

To the left of the belt is a brighter band (the North North Temperate Zone) with high clouds whose vertical relief is accentuated by the low angle of sunlight near the terminator. These clouds are likely made of ammonia-ice crystals, or possibly a combination of ammonia ice and water. Although the region as a whole appears chaotic, there is an alternating pattern of rotating, lighter-colored features on the zone's north and south sides.

Scientists think the large-scale dark regions are places where the clouds are deeper, based on infrared observations made at the same time by Juno’s JIRAM experiment and Earth-based supporting observations. Those observations show warmer, and thus deeper, thermal emission from these regions.

Juno orbiting Jupiter. Animation Credit: NASA

To the right of the bright zone, and farther north on the planet, Jupiter’s striking banded structure becomes less evident and a region of individual cyclones can be seen, interspersed with smaller, darker anticyclones.

Citizen scientist Kevin M. Gill created this image using data from the spacecraft’s JunoCam imager.

JunoCam's raw images are available for the public to peruse and process into image products at: http://www.missionjuno.swri.edu/junocam

More information about Juno is at: https://www.nasa.gov/juno and http://missionjuno.swri.edu

Image, Animation (mentioned), Text, Credits: NASA/Tony Greicius/JPL-Caltech/SwRI/MSSS/Kevin M. Gill.

Greetings, Orbiter.ch

Russian Aerospace Forces Successfully Launched the Soyuz-2.1b Rocket Carrying Glonass-M












Russian Aerospace Forces - GLONASS patch.

June 18, 2018

 Souyz-2.1b rocket carrying Glonass-M launch from Plesetsk Cosmodrome

On June 17, 2018, at 0:46 MT, Russian Aerospace Forces have successfully launched the Souyz-2.1b rocket vehicle with a Glonass-M spacecraft from the Plesetsk Cosmodrome. Launch of the rocket vehicle and ascent to orbit were held under normal conditions.

Soyuz-2.1b launches GLONASS-M navigation satellite

A Russian government Soyuz rocket launches a Glonass M navigation satellite. The rocket flight in the Soyuz 2-1b configuration with a Fregat upper stage.

GLONASS-M satellite

In three minutes after the launch, the Soyuz-2.1b was tracked by ground automated control complex of the Main Test Space Centre named after German Titov.

Roscosmos Press Release: http://en.roscosmos.ru/20736/

Images, Text, Video, Text, Credits: ROSCOSMOS/SciNews.

Greetings, Orbiter.ch

dimanche 17 juin 2018

Astronomers See Distant Eruption as Black Hole Destroys Star














NASA - Hubble Space Telescope patch / NASA - Spitzer Space Telescope patch.

June 17, 2018

For the first time, astronomers have directly imaged the formation and expansion of a fast-moving jet of material ejected when the powerful gravity of a supermassive black hole ripped apart a star that wandered too close to the massive monster.

The scientists tracked the event with radio and infrared telescopes, including the National Science Foundation's Very Long Baseline Array (VLBA) and NASA's Spitzer Space Telescope, in a pair of colliding galaxies called Arp 299. The galaxies are nearly 150 million light-years from Earth. At the core of one of the galaxies, a black hole 20 million times more massive than the Sun shredded a star more than twice the Sun's mass, setting off a chain of events that revealed important details of the violent encounter. The researchers also used observations of Arp 299 made by NASA's Hubble space telescope prior to and after the appearance of the eruption.

Black Hole vs. Star: A Tidal Disruption Event (Artist's Concept)

Image above: An artist's concept of a tidal disruption event (TDE) that happens when a star passes fatally close to a supermassive black hole, which reacts by launching a relativistic jet. Image Credits: Sophia Dagnello, NRAO/AUI/NSF.

Only a small number of such stellar deaths, called tidal disruption events, or TDEs, have been detected. Theorists have suggested that material pulled from the doomed star forms a rotating disk around the black hole, emitting intense X-rays and visible light, and also launches jets of material outward from the poles of the disk at nearly the speed of light.

"Never before have we been able to directly observe the formation and evolution of a jet from one of these events," said Miguel Perez-Torres, of the Astrophysical Institute of Andalucia in Granada, Spain, and an author on a paper describing the finding.

Discovery of a jet

The first indication came on January 30, 2005, when astronomers using the William Herschel Telescope in the Canary Islands discovered a bright burst of infrared emission coming from the nucleus of one of the colliding galaxies in Arp 299. On July 17, 2005, the VLBA revealed a new, distinct source of radio emission from the same location.

A Tidal Disruption Event in Arp299B

Image above: An image of the galaxy Arp299B, which is undergoing a merging process with Arp299A (the galaxy to the left), captured by NASA's Hubble space telescope. The inset features an artist's illustration of a tidal disruption event (TDE), which occurs when a star passes fatally close to a supermassive black hole. A TDE was recently observed near the center of Arp299B. Image Credits: Sophia Dagnello, NRAO/AUI/NSF; NASA, STScI.

"As time passed, the new object stayed bright at infrared and radio wavelengths, but not in visible light and X-rays," said Seppo Mattila, of the University of Turku in Finland, another author on the new paper. "The most likely explanation is that thick interstellar gas and dust near the galaxy's center absorbed the X-rays and visible light, then re-radiated it as infrared." The researchers used the Nordic Optical Telescope on the Canary Islands and NASA's Spitzer to follow the object's infrared emission.

Continued observations with the VLBA, the European VLBI Network (EVN), and other radio telescopes, carried out over nearly a decade, showed the source of radio emission expanding in one direction, just as expected for a jet. The measured expansion indicated that the material in the jet moved at an average of one-fourth the speed of light. The radio waves are not absorbed by the dust, but pass through it.

These observations used multiple radio-telescope antennas, separated by thousands of miles, to gain the resolving power, or ability to see fine detail, required to detect the expansion of an object so distant.

Monster appetite

Most galaxies have supermassive black holes, containing millions to billions of times the mass of the Sun, at their cores. In a black hole, the mass is so concentrated that its gravitational pull is so strong that not even light can escape. When those supermassive black holes are actively drawing in material from their surroundings, that material forms a rotating disk around the black hole, and super-fast jets of particles are launched outward. This is the phenomenon seen in radio galaxies and quasars.


Image above: A diagram showing the components of the TDE observed in Arp299B. (Not to scale). The supermassive black hole at the center of the galaxy is surrounded by a highly dense medium, and embedded in a dusty torus. Most of the optical and X-ray emissions produced by the event were absorbed, and re-emitted at infrared (IR) wavelengths due to the existence of polar dust. A few months after the detection at IR wavelengths, the TDE was detected at radio wavelengths with the help of a very sensitive array of radio telescopes. Image Credits: Seppo Mattila, Miguel Pérez-Torres et al. 2018 (Science).

"Much of the time, however, supermassive black holes are not actively devouring anything, so they are in a quiet state," Perez-Torres explained. "Tidal disruption events can provide us with a unique opportunity to advance our understanding of the formation and evolution of jets in the vicinities of these powerful objects."

"Because of the dust that absorbed any visible light, this particular tidal disruption event may be just the tip of the iceberg of what until now has been a hidden population," Mattila said. "By looking for these events with infrared and radio telescopes, we may be able to discover many more, and learn from them."

Spitzer Space Telescope (SST).  Animation Credit: NASA

Such events may have been more common in the distant universe, so studying them may help scientists understand the environment in which galaxies developed billions of years ago.

The discovery, the scientists said, came as a surprise. The initial infrared burst was discovered as part of a project that sought to detect supernova explosions in such colliding pairs of galaxies. Arp 299 has seen numerous stellar explosions, and has been dubbed a "supernova factory." This new object originally was considered to be a supernova explosion. Only in 2011, six years after discovery, the radio-emitting portion began to show an elongation. Subsequent monitoring showed the expansion growing, confirming that what the scientists are seeing is a jet, not a supernova.

Hubble Space Telescope (HST). Animation Credits: NASA/ESA

Mattila and Perez-Torres led a team of 36 scientists from 26 institutions around the world in the observations of Arp 299. They published their findings in the June 14 issue of the journal Science.

The Long Baseline Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc. NASA's Jet Propulsion Laboratory, Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at IPAC at Caltech. Caltech manages JPL for NASA.

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.

For more information about NASA's Hubble Space Telescope, visit: https://www.nasa.gov/hubble

For more information about NASA's Spitzer Space Telescope, visit: https://www.nasa.gov/spitzer

Images (mentioned), Animations (mentioned), Text, Credits: NASA/JPL/Calla Cofield/NRAO/Dave Finley.

Greetings, Orbiter.ch