samedi 28 novembre 2020

Chang’e-5 enters lunar orbit


CLEP - China Lunar Exploration Program logo.

Nov. 28, 2020

The Chang’e-5 lunar mission has successfully performed a braking maneuver on 28 November 2020, at 12:58 UTC (20:58 China Standard Time), and entered into an elliptical orbit around the Moon.

Chang’e-5 enters lunar orbit

The Chang’e-5 lunar mission will attempt to land near Mons Rümker, a volcanic complex in the northern region of Oceanus Procellarum. The spacecraft will try to collect about 2 kilograms of lunar soil and return the samples to Earth.

Chang’e-5 (嫦娥五号) mission diagram

According to Lin Yangting (professor, Institute of Geology and Geophysics, Chinese Academy of Sciences), a joint team will be formed with European researchers to study the samples, part of the cooperation with the European Space Agency.

Related articles:

Chang’e-5 completes first orbital correction

CASC - Long March-5 Y5 launches Chang’e-5 lunar mission

ESA tracks Chang'e-5 Moon mission

Related links:

For more information about China Aerospace Science and Technology Corporation (CASC), visit:

For more information about China National Space Administration (CNSA), visit:

Image, Video, Text, Credits: China Central Television (CCTV)/CASC/CNSA/SciNews/ Aerospace/Roland Berga.

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SpaceX Starlink 15 launch


SpaceX - Falcon 9 / Starlink Mission patch.

Nov. 28, 2020

SpaceX Falcon 9 rocket launch Starlink 15

A SpaceX Falcon 9 rocket launched 60 Starlink satellites (Starlink-16) from  Space Launch Complex 40 (SLC-40) at Cape Canaveral Air Force Station, on 25 November 2020, at 02:13 UTC (24 November, 21:13 EDT).

SpaceX Starlink 15 launch & Falcon 9 first stage landing, 25 November 2020

Following stage separation, Falcon 9’s first stage (B1049) landed on the “Of Course I Still Love You” droneship, stationed in the Atlantic Ocean. 

Falcon 9’s first stage landed on the “Of Course I Still Love You” droneship

A SpaceX Falcon 9 rocket launches the 16th batch of approximately 60 satellites for SpaceX’s Starlink broadband network, a mission designated Starlink V1.0-L15. Delayed from October and Nov. 21. Scrubbed on Nov. 22. Delayed from Nov. 23.

Falcon 9’s first stage previously supported six other missions: the Telstar 18 VANTAGE mission in September 2018, the Iridium-8 mission in January 2019, and four Starlink missions in May 2019, January 2020, June 2020, and August 2020.


Images, Video. Text, Credits: SpaceX/SciNews/ Aerospace/Roland Berga.


vendredi 27 novembre 2020

Muscle Study and Emergency Training Wrap Up Work Week


ISS - Expedition 64 Mission patch.

Nov. 27, 2020

The main science focus today aboard the International Space Station was a human research study observing an astronaut’s muscular system. All seven Expedition 64 crew members also gathered together Friday afternoon and familiarized themselves with emergency hardware.

Flight Engineer Michael Hopkins kicked off the Myotones study Friday morning gathering hardware to collect measurements of his muscles and tendons. Crewmates Victor Glover and Shannon Walker also joined Hopkins for the muscle scans and measurements. Methods such as an ultrasound scan and blood draws are used to look at the biomechanical properties of muscles. Observations may improve performance and fitness in space as well as treatments for rehabilitation on Earth.

Image above: The sun’s glint beams off the Atlantic Ocean creating a bright golden sheen as the International Space Station orbited off the coast of the United States. Image Credit: NASA.

A pair of studies looking at botany and fluid technology was also on Friday’s research schedule. Rubins collected and stowed leaf samples from radish plants growing in the Columbus laboratory module. She also explored the behavior of water droplets with an eye towards developing advanced fuel and life support systems.

JAXA astronaut Soichi Noguchi relaxed Friday morning before moving onto lab maintenance activities. The three-time space visitor first serviced U.S. spacesuit batteries before closing out the Avatar-X robotic camera experiment. He also worked on light plumbing duties servicing components in the station’s restroom located in the Tranquility module.

International Space Station (ISS). Animation Credit: ESA

Crews aboard the station regularly practice emergency drills such as evacuations or medical procedures in conjunction with mission controllers on the ground. Today, all the station residents, including Commander Sergey Ryzhikov and Flight Engineer Sergey Kud-Sverchkov, familiarized themselves with emergency gear to be prepared for an unlikely emergency scenario in space.

Related links:

Expedition 64:



Plant Habitat-02 (radish plant):

Drop Vibration (water droplets):

Columbus laboratory module:

Tranquility module:

Space Station Research and Technology:

International Space Station (ISS):

Image (mentioned), Animation (mentioned), Text, Credits: NASA/Norah Moran.

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Russian and Indian satellites avoid a collision in space from 200m distance



Nov. 27, 2020

According to the main information and analytical center of the automated warning system for dangerous situations in near-earth space (GIAC ASPOS OKP) TsNIIMash (part of the Roscosmos State Corporation), on November 27, 2020 at 04:49 Moscow time, there was a dangerous approach with the Russian spacecraft the Canopus-V and the operating Indian CARTOSAT 2F apparatus, satellites weighing more than 700 kg.

Satellite collisions create space debris. Image Credit: DARPA

According to the calculations of the GIAC ASPOS OKP, the minimum distance between the Russian and foreign satellites was 224 meters. Both devices are designed for remote sensing of the Earth.

ROSCOSMOS Press Release:

Image (mentioned), Text, Credits: ROSCOSMOS/ Aerospace/Roland Berga.


Turning Moon dust into oxygen


ESA - European Space Agency patch.

Nov. 27, 2020

British engineers are fine-tuning a process that will be used to extract oxygen from lunar dust, leaving behind metal powders that could be 3D printed into construction materials for a Moon base.

It could be an early step to establishing an extra-terrestrial oxygen extraction plant. This would help to enable exploration and sustain life on the Moon while avoiding the enormous cost of sending materials from Earth.

Lunar base made with 3D printing

The oxygen generated would mostly be used to make rocket fuel, but could also provide air for lunar settlers.

The project is part of ESA’s preparations to establish a permanent and sustainable lunar presence. Astronauts will live and work on the Moon, where they will help to develop and test technologies needed for missions farther into deep space.

Lunar regolith, the thin layer of dusty rock that blankets the Moon, is not so different from the minerals found on Earth. By weight, it contains about 45% oxygen which is bound to metals such as iron and titanium, making it unavailable.

British company Metalysis has already developed a mineral extraction process that is used by industries on Earth to produce metals for manufacturing.

Image above: Researchers at ESA showed the technique could extract oxygen from simulated Moon dust.

Earlier this year, it was demonstrated to work well with simulated lunar regolith.

The electrochemical process takes place in a specially designed chamber – the ones used for research are about the size of a washing machine. Oxygen-containing material is submerged in a molten salt, heated to 950°C. A current is then passed through it, which triggers the oxygen to be extracted and migrate across the liquid salt to collect at an electrode, leaving behind a mixture of metal powders.

As part of the current project, Metalysis engineers are fine-tuning the technique with its lunar application in mind.

The big difference is that, on Earth, the oxygen generated is not needed, but in space it will be the most important product of the process. This means it needs to be engineered to produce as much of the gas as possible.

Engineers will tinker with the process by adjusting the electrical current and reagents to boost the amount of oxygen, while trying to reduce the temperature needed to produce it. This will help bring down the energy required, which is already at a premium on the Moon.

They will also work to reduce the size of the chamber the process takes place in so that it can be transported efficiently to the Moon.

Oxygen and metal from lunar regolith

In parallel, ESA and Metalysis have challenged innovators to develop an in-process monitoring system that could be used to keep track of oxygen production in future lunar extraction plants.

“Some years ago we realised that the seemingly unimportant by-product of our terrestrial mineral extraction process could have far-reaching applications in space exploration,” says Ian Mellor, managing director at Metalysis

“We look forward to continuing to explore with ESA, and our industrial partners, how to get our Earthly technology space-ready.”

“This exciting project forms part of ESA’s wider Space Resources Strategy which will help us demonstrate how material already present on the Moon can be used sustainably to support long-term space endeavours,” says Advenit Makaya, the ESA materials engineer who is overseeing the project.

“The project will help us learn more about Metalysis’ process, and may even be a stepping stone to establishing an automated pilot oxygen plant on the Moon – with the added bonus of metal alloys that could be used by 3D printers to create construction materials.”

"In the future, if we want to travel extensively in space and set up bases on the Moon and Mars, then we will need to make or find the things required to support life - food, water and breathable air," says Sue Horne, head of space exploration at the UK Space Agency.

"The involvement of Metalysis in a programme that aims to do just that, by producing oxygen on a lunar setting, will showcase the UK's space credentials on the world-stage and help unlock breakthroughs that bring future space exploration a step closer."

Related links:

ESA and Metalysis have challenged innovators:

Human and Robotic Exploration:

Science & Exploration:

Images, Text, Credits: ESA/A. Conigili/Foster + Partners/Beth Lomax - University of Glasgow.

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Star Survives Close Call with a Black Hole


NASA - Chandra X-ray Observatory patch.

Nov. 27, 2020

Astronomers may have discovered a new kind of survival story: a star that had a brush with a giant black hole and lived to tell the tale through exclamations of X-rays.

Data from NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton uncovered the account that began with a red giant star wandering too close to a supermassive black hole in a galaxy about 250 million light years from Earth. The black hole, located in a galaxy called GSN 069, has a mass about 400,000 times that of the Sun, putting it on the small end of the scale for supermassive black holes.

Once the red giant was captured by the black hole’s gravity, the outer layers of the star containing hydrogen were stripped off and careened toward the black hole, leaving the core of the star – known as a white dwarf – behind.

“In my interpretation of the X-ray data the white dwarf survived, but it did not escape,” said Andrew King of the University of Leicester in the UK, who performed this study. “It is now caught in an elliptical orbit around the black hole, making one trip around about once every nine hours.”

Image above: Astronomers may have discovered a new kind of survival story: a star that had a brush with a giant black hole and lived to tell the tale through exclamations of X-rays. Data from NASA’s Chandra X-ray Observatory and ESA’s XMM-Newton uncovered the account that began with a red giant star wandering too close to a supermassive black hole in a galaxy about 250 million light years from Earth. The black hole, located in a galaxy called GSN 069, has a mass about 400,000 times that of the Sun, putting it on the small end of the scale for supermassive black holes. Image Credits: X-ray: NASA/CXO/CSIC-INTA/G.Miniutti et al.; Illustration: NASA/CXC/M. Weiss.

As the white dwarf makes its nearly thrice-daily orbit, the black hole pulls material off at its closest approach (no more than 15 times the radius of the event horizon – the point of no return – away from the black hole). The stellar detritus enters into a disk surrounding the black hole and releases a burst of X-rays that Chandra and XMM-Newton can detect. In addition, King predicts gravitational waves will be emitted by the black hole and white dwarf pair, especially at their nearest point.

What would be the future of the star and its orbit? The combined effect of gravitational waves and an increase in the star’s size as it loses mass should cause the orbit to become more circular and grow in size. In this case, the rate of mass loss steadily slows down, and the white dwarf slowly spirals away from the black hole.

“It will try hard to get away, but there is no escape. The black hole will eat it more and more slowly, but never stop,” said King. “In principle, this loss of mass would continue until and even after the white dwarf became a planet, with a mass similar to Jupiter, in about a trillion years. This would be a remarkably slow and convoluted way for the universe to make a planet!”

Astronomers have found many stars that have been completely torn apart by encounters with black holes (so-called tidal disruption events), but there are very few reported cases of near misses, where the star likely survived.

Black Holes Neutron Stars White Dwarfs Beyond Space and Time

Grazing encounters like this should be more common than direct collisions given the statistics of cosmic traffic patterns, but they could easily be missed for a couple of reasons. First, it can take a more massive, surviving star too long to complete an orbit around a black hole for astronomers to see repeated bursts. Another issue is that supermassive black holes that are much more massive than the one in GSN 069 may directly swallow a star rather than the star falling into orbits where they periodically lose mass. In these cases, astronomers wouldn’t observe anything.

“In astronomical terms, this event is only visible to our current telescopes for a short time – about 2,000 years,” said King. “So unless we were extraordinarily lucky to have caught this one, there may be many more that we are missing. Such encounters could be one of the main ways for black holes the size of the one in GSN 069 to grow.”

King predicts that the white dwarf has a mass of only two tenths the mass of the Sun. If the white dwarf was the core of the red giant that was completely stripped of its hydrogen, then it should be rich in helium. The helium would have been created by the fusion of hydrogen atoms during the evolution of the red giant.

“It’s remarkable to think that the orbit, mass and composition of a tiny star 250 million light years away could be inferred,” said King.

King made a prediction based on his scenario. Because the white dwarf is so close to the black hole, effects from the Theory of General Relativity mean that the direction of the orbit's axis should wobble, or “precess.” This wobble should repeat every two days and may be detectable with sufficiently long observations.

A paper describing these results appears in the March 2020 issue of the Monthly Notices of the Royal Astronomical Society, and is available online. NASA's Marshall Space Flight Center manages the Chandra program. The Smithsonian Astrophysical Observatory's Chandra X-ray Center controls science and flight operations from Cambridge and Burlington, Massachusetts.

Related links:

ESA XMM-Newton:

NASA Chandra X-Ray Observatory:

Marshall Space Flight Center:

Image (mentioned), Video (ESA/NASA), Text, Credits: NASA/William Bryan/Chandra X-ray Center/Megan Watzke/Marshall Space Flight Center/Molly Porter.


jeudi 26 novembre 2020

Chang’e-5 completes first orbital correction


CLEP - China Lunar Exploration Program logo.

Nov. 26, 2020

On 24 November 2020, at 14:06 UTC (22:06 Beijing Time), the Chang’e-5 spacecraft successfully performed its first orbital correction.

Chang’e-5 completes first orbital correction

China’s Chang’e-5 lunar mission was launched by the Long March-5 Y5 launch vehicle on 23 November 2020, at 20:30 UTC (24 November, 04:30 local time).

Chang’e-5 (嫦娥五号) mission diagram

The Chang’e-5 lunar mission will attempt to land near Mons Rümker, a volcanic complex in the northern region of Oceanus Procellarum. The spacecraft will try to collect about 2 kilograms of lunar soil and return the samples to Earth.

Chang’e-5 to sample Mons Rümker, Oceanus Procellarum

According to Lin Yangting (professor, Institute of Geology and Geophysics, Chinese Academy of Sciences), a joint team will be formed with European researchers to study the samples, part of the cooperation with the European Space Agency (ESA).

Chang’e-5 (嫦娥五号) mission, takeoff from Lunar surface

Related articles:

CASC - Long March-5 Y5 launches Chang’e-5 lunar mission

ESA tracks Chang'e-5 Moon mission

For more information about China Aerospace Science and Technology Corporation (CASC), visit:

For more information about China National Space Administration (CNSA), visit:

Image, Videos, Text, Credits: China Central Television (CCTV)/CASC/CNSA/SciNews/ Aerospace/Roland Berga.


Precise maps of millions of bright quasars show our place in the cosmos as never before


ESA - Gaia Mission patch.

Nov. 26, 2020

On a Friday at the end of 2018, the top brass of a NASA deep space mission convened for a tense meeting. Hour by hour the New Horizons probe was hurtling toward a New Year’s Day rendezvous with Arrokoth, an ancient, icy rock at the edge of the Solar System. The team had one last chance to send instructions for pointing the probe’s cameras. Success would ensure in-frame pictures of Arrokoth, and the clues it held for how the planets formed. Failure would mean expensive pictures of an empty void.

The mission managers who gathered at New Horizons headquarters in suburban Maryland realized they had a “massive problem,” says Marc Buie, a team member and planetary scientist at the Southwest Research Institute in Boulder, Colorado. Something was off in images already beamed back. Either the flying spacecraft or the orbiting rock was a teensy bit lost in a universe where nothing is nailed down.

Image above: Quasars, generated by black holes in distant galaxies, are far more stable beacons than nearby stars. Image Credits: J. PAULSON/ALAMY STOCK PHOTO.

The team debated what to fix. Some thought the probe’s position, calculated from Earth-based measurements, was correct, in which case Arrokoth was in an unexpected place. But Buie believed the rock was right where it should be, which suggested thrusters had nudged the spacecraft itself a hair off course.

Buie was confident because he was tracking Arrokoth’s position relative to an ultraprecise map of far-off beacons called quasars: cosmic lighthouses generated by black holes in distant galactic centers. But the map was largely untested, having just been released by a European Space Agency star-mapping satellite called Gaia. It was the basis of a brand-new celestial reference frame, a fixed, imaginary grid against which everything else moves, akin to lines of latitude and longitude on Earth. And Buie was gambling the Arrokoth flyby on that new grid.

For the past few decades, astronomers have based their celestial grid on radio observations of several thousand quasars. These radio beacons not only guide the pointing of telescopes, but they are also the bedrock of the reference frame for the spinning, bucking Earth. Without them, GPS devices would lose their accuracy and many ultraprecise studies of processes such as plate tectonics and climate change would be impossible. But observations of these beacons are costly and rely on radio telescopes.

By 2018, when New Horizons was approaching Arrokoth, Gaia had produced its own version of a reference frame, based on half a million quasars seen in the visible wavelengths most astronomers use, not radio. Buie persuaded the New Horizons team to trust the new framework. A correction based on the Gaia positions went up to the probe.

The team got it right: When the closest flyby images came back, Arrokoth was framed perfectly. “None of that would have happened if we hadn’t had the Gaia catalog,” Buie says. “It’s a fundamental rewriting of how we do positional astronomy.”

The rewriting has continued. Next week, on 3 December, Gaia will release, along with the latest data about billions of Milky Way stars, its newest reference frame, built from 1.6 million quasars scattered across the sky. “It is improved, larger, better, more beautiful,” says François Mignard, an astronomer at the Côte d’Azur Observatory in France who leads Gaia’s reference frame team.

The Gaia reference frame is only the latest solution to a very, very old problem. From planets to comets to asteroids, much of the sky drifts from night to night. Studying these objects would be hopeless without comparing them with points that stay still.

At first, the stars looked like trustworthy reference points. In the second century C.E., the Alexandrian astronomer Ptolemy revisited constellations his predecessor Hipparcos had observed some 3 centuries earlier. With his naked eyes, Ptolemy couldn’t find any movement among the stars, which he assumed were fixed points on a sphere rotating around Earth.

But by the 1700s, careful observations with telescopes proved the stars’ apparent positions in the sky do shift over the years, as they move through the cosmos. In response, astronomers spent whole lifetimes building catalogs of stars far enough away or slow enough to mostly stay still.

Image above: Next week, Europe’s star-mapping Gaia mission will release a new celestial reference frame, built from the positions of 1.6 million quasars. Image Credits: ESA/ATG MEDIALAB; ESO/S. BRUNIER.

The game changed again when astronomers started to observe quasars in the 1970s, using radio dishes on different continents to make hyperprecise measurements of their positions. Like stars, quasars appear as points of light. But they are billions of light-years away, so they barely budge within human lifetimes. Finally, the distant sky, not Earth, was the ultimate arbiter of where things are.

Today, the radio measurements feed into a global bureaucracy that maintains reference frames, imposing order on space in the same way astronomical observatories used to keep time. Many of the quasar measurements are accurate to about a hundred-millionth of a degree—smaller than the apparent size of a basketball on the Moon. They not only hold the sky in place, but also reveal jerks in Earth’s rotation speed and wobbles in its axis that arise from earthquakes and hurricanes. The calculated tweaks are used in turn to correct GPS devices, which would otherwise lose track of Earth’s spinning surface.

The growing number of rock-solid quasars, now in the thousands, also transformed interplanetary navigation. For decades, NASA tracked its spacecraft mainly by measuring their velocities as they flew away, which made it possible to calculate their distances from Earth. Their positions in other dimensions were only coarsely estimated by the sensors on the spacecraft. But after a pair of high-profile Mars failures in 1999, the agency added another method: It looks for quasars that are near the craft’s current location in the sky—anchoring the probe to the reference frame. The approach has enabled subsequent bull’s-eye landings on Mars and elsewhere, says Barry Geldzahler, who recently retired as NASA’s navigation lead. “We make the hard things routine, and kind of boring.”

For the many space scientists who work outside of radio wavelengths, however, a radio-based reference frame isn’t so useful. Astronomers had spent decades trying to build up rival reference points in visible light. But quasars are faint specks at those wavelengths, and optical telescopes peering through Earth’s blurry atmosphere struggled to match the precision of radio arrays.

Then the 2018 Gaia data set dropped, after the probe scanned the whole sky with sensitive space-based detectors. “Ninety-eight percent of that work was obliterated after the Gaia release,” says Leonid Petrov, an astronomer at NASA’s Goddard Space Flight Center who conducts radio quasar observations to build reference frames. “In 1 day, they became history.”

The consensus grid for outer space—the third iteration of the official International Celestial Reference Frame, maintained by the International Astronomical Union (IAU)—still relies on radio quasars. But at the next IAU general assembly in 2021, Mignard says he plans to propose a multi-wavelength system, with the optical quasar positions listed alongside the radio ones.

Tiny offsets between the two systems can already be seen, but they are not errors. They reflect astrophysical reality—and a tantalizing research opportunity. Quasars are powered by gas swirling around supermassive black holes at the centers of galaxies. As the gas circles the drain, it kicks out bright jets of plasma at nearly the speed of light. The radio telescopes are trained on the black hole itself, whereas Gaia picks up an average position between the black hole and the jets. No single telescope can distinguish between these locations. But the discrepancies between the radio and optical positions point to these fine details and offer a new way to investigate the physics at galaxy centers.

“If you’re a fan of active galactic nuclei, this is a great time to be alive,” says Bryan Dorland, an astronomer at the U.S. Naval Observatory. “The last time positional astronomy was exciting was around, like, Ptolemy. Right?”

Eventually, the Gaia data might even feed back into terrestrial position-finding systems, but not before lengthy studies and negotiations, says Manuela Seitz, of the German Geodetic Research Institute. “It’s a long way between showing, OK, you can have an improvement if you use it to, OK, you now have products which are really consistent,” she says.

To stay useful, the Gaia system will require tending. Right now, it has a firm handle on not just its quasars, but also more than 1 billion closer, drifting stars. These stars, anchored to the quasar-based grid, are useful guides for spacecraft with simple star trackers, or when no quasar is visible in a particular part of the sky. But the Gaia mission is set to end its vigil in 2025. After that, the stars will meander relative to background quasars unless astronomers dispatch a follow-up mission to remap the sky.

Meanwhile, the quasars themselves will drift glacially. Ultimately, Mignard says, high-precision reference frames of the future might require anchors even more stable than quasars: perhaps points on the cosmic microwave background, the afterglow of the big bang, which lies at the farthest observable distance in the cosmos.

Buie, for his part, plans to use the Gaia reference frame for as long as he can in his work pinpointing and studying tiny outer Solar System rocks. The Gaia data make it easier for him to calculate when and where to go on Earth to watch a star wink out as a remote object crosses in front of it—a so-called occultation event that relies on the momentary backlight to reveal details about the object.

He’s also playing the same game he did with New Horizons and Arrokoth for Lucy, an upcoming NASA mission that plans to buzz past five small asteroids near the orbit of Jupiter. The extra precision of the Gaia system will help mission controllers home in precisely on their targets. “They don’t think they need it, but they do,” Buie says.


Related articles:

Largest 3D Universe Map Released

A new technique to gauge the distant Universe

Related link:


Images (mentioned), Text, Credits: ESA/Space/Science/Joshua Sokol.

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New Hubble Data Explains Missing Dark Matter


ESA - Hubble Space Telescope logo.

Nov. 26, 2020

New data from the NASA/ESA Hubble Space Telescope provides further evidence for tidal disruption in the galaxy NGC 1052-DF4. This result explains a previous finding that this galaxy is missing most of its dark matter. By studying the galaxy’s light and globular cluster distribution, astronomers have concluded that the gravity forces of the neighbouring galaxy NGC 1035 stripped the dark matter from NGC 1052-DF4 and are now tearing the galaxy apart.

Ground-based view of the sky around the galaxies NGC 1052-DF4 NGC & 1052-DF2

In 2018 an international team of researchers using the NASA/ESA Hubble Space Telescope and several other observatories uncovered, for the first time, a galaxy in our cosmic neighbourhood that is missing most of its dark matter. This discovery of the galaxy NGC 1052-DF2 was a surprise to astronomers, as it was understood that Dark matter (DM) is a key constituent in current models of galaxy formation and evolution. In fact, without the presence of DM, the primordial gas would lack enough gravity pull to start collapsing and forming new galaxies. A year later, another galaxy that misses dark matter was discovered, NGC 1052-DF4, which further triggered intense debates among astronomers about the nature of these objects.

Now, new Hubble data [1] have been used to explain the reason behind the missing dark matter in NGC 1052-DF4, which resides 45 million light-years away. Mireia Montes of the University of New South Wales in Australia led an international team of astronomers to study the galaxy using deep optical imaging. They discovered that the missing dark matter can be explained by the effects of tidal disruption. The gravity forces of the neighbouring massive galaxy NGC 1035 are tearing NGC 1052-DF4 apart. During this process, the dark matter is removed, while the stars feel the effects of the interaction with another galaxy at a later stage.

Until now, the removal of dark matter in this way has remained hidden from astronomers as it can only be observed using extremely deep images that can reveal extremely faint features. “We used Hubble in two ways to discover that NGC 1052-DF4 is experiencing an interaction,” explained Montes. “This includes studying the galaxy’s light and the galaxy’s distribution of globular clusters.”

 Region around Galaxy NGC1052-DF4

Thanks to Hubble’s high resolution, the astronomers could identify the galaxy’s globular clusters population. The 10.4-metre Gran Telescopio Canarias (GTC) telescope and the IAC80 telescope in the Canaries, Spain, were also used to complement Hubble’s observations by further studying the data.

“It is not enough just to spend a lot of time observing the object, but a careful treatment of the data is vital,” explained team member Raúl Infante-Sainz of the Instituto de Astrofísica de Canarias in Spain. “It was therefore important that we use not just one telescope/instrument, but several (both ground- and space-based) to conduct this research. With the high resolution of Hubble, we can identify the globular clusters, and then with GTC photometry we obtain the physical properties.”

Globular clusters are thought to form in the episodes of intense star formation that shaped galaxies. Their compact sizes and luminosity make them easily observable and they are therefore good tracers of the properties of their host galaxy. In this way, by studying and characterising the spatial distribution of the clusters in NGC 1052-DF4, astronomers can develop insight into the present state of the galaxy itself. The alignment of these clusters suggests they are being “stripped” from their host galaxy, and this supports the conclusion that tidal disruption is occurring.

By studying the galaxy’s light, the astronomers also found evidence of tidal tails, which are formed of material moving away from NGC1052-DF4 — this further supports the conclusion that this is a disruption event. Additional analysis concluded that the central parts of the galaxy remain untouched and only ∼ 7% of the stellar mass of the galaxy is hosted in these tidal tails. This means that dark matter, which is less concentrated than stars, was previously and preferentially stripped from the galaxy, and now the outer stellar component is starting to be stripped as well.

“This result is a good indicator that, while the dark matter of the galaxy was evaporated from the system, the stars are only now starting to suffer the disruption mechanism,” explained team member Ignacio Trujillo of the Instituto de Astrofísica de Canarias in Spain. “In time, NGC1052-DF4 will be cannibalised by the large system around NGC1035, with at least some of their stars floating free in deep space.”

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

The discovery of evidence to support the mechanism of tidal disruption as the explanation for the galaxy’s missing dark matter has not only solved an astronomical conundrum, but has also brought a sigh of relief to astronomers. Without it, scientists would be faced with having to revise our understanding of the laws of gravity.

“This discovery reconciles existing knowledge of how galaxies form and evolve with the most favorable cosmological model,” added Montes.


[1] These results were achieved using data from Hubble Space Telescope programs GO-14644 and GO-15695 (PI: van Dokkum).

More information:

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

The international team of astronomers in this study consists of M. Montes, R. Infante-Sainz, A. Madrigal-Aguado, J. Román, M. Monelli, A. S. Borlaff, and I. Trujillo.

These results have been published in the Astrophysical Journal.


Images of Hubble:

Science paper:

Instituto de Astrofísica de Canarias release:

Link to Space Scoop - a kid friendly version of this news:

Images Credits: ESA/Hubble, NASA, Digitzed Sky Survey 2. Acknowledgement: Davide de Martin/School of Physics, University of New South Wales/M. Montes et al./Instituto de Astrofísica de Canarias/Ignacio Trujillo/ESA/Hubble, Public Information Officer/Bethany Downer.

ESA and ClearSpace SA Sign Contract for World's First Debris Removal Mission


ESA - ClearSpace logo.

Nov. 26, 2020

ESA signs an 86 million euro contract with an industrial team led by the young Swiss company ClearSpace SA for the purchase of a unique service: the first removal of space debris in orbit.


So in 2025 ClearSpace SA will launch the first active debris removal mission, ClearSpace-1, which will rendezvous with a Vespa payload adapter to capture and deorbit it.

A new methodology for ESA

At the Space19 + Ministerial Council, ministers granted ESA the necessary funding to enter into a service contract with a commercial supplier for the safe removal of an inactive object in low earth orbit.

Following a competitive process, an industrial team led by ClearSpace SA, a spin-off company of the Federal Polytechnic School of Lausanne (EPFL), was invited to submit the final proposal. With the signing of this contract, a crucial step in establishing a new business sector in space will be taken.

ClearSpace-1 with captured Vespa

Purchasing the mission as part of an end-to-end service contract, rather than developing an ESA-defined spacecraft for in-house operation, represents a new approach for ESA. ESA purchases the initial mission and provides key expertise within the framework of the ADRIOS (Active Debris Removal / In-Orbit Servicing) project of its Space Security program. ClearSpace SA will finance the remaining cost of the assignment through commercial investors.

The size of the target, Vespa, is close to that of a small satellite

The ClearSpace-1 mission will target a Vespa dual-launch carrier structure of the Vega rocket, left after the second flight of the European Vega launcher in 2013 in an orbit meeting debris mitigation standards, at an altitude of approximately 660 km to 800 km. With a mass of 112 kg, the size of the target, Vespa, is close to that of a small satellite.

Process of Vespa capture

In nearly 60 years of space activity, more than 5,550 launches have tracked 42,000 objects in orbit, of which approximately 23,000 are still in space and are being tracked regularly. With an average today of nearly one hundred launches annually, and with decays continuing to occur at a historic average rate of four to five per year, the number of space debris will continue to steadily increase.

Image above: ClearSpace-1 will target the tapered top portion of the payload adapter that put Proba-V into orbit.

ClearSpace-1 will demonstrate its technical and commercial ability to significantly enhance the long-term sustainability of spaceflight. The mission is supported under the ESA Space Security program, based at the ESOC Operations Center located in Darmstadt, Germany.

Participation of European industry in ClearSpace-1

Companies from a large number of European countries are participating in the ClearSpace-1 mission. While the management of the industrial team is provided by ClearSpace AG, contributions come from companies in Switzerland, the Czech Republic, Germany, Sweden, Poland, the United Kingdom, Portugal and Romania.

Distribution of space debris around the Earth

Media representatives are invited to attend an online panel discussion on Tuesday, December 1 from 1:30 p.m. to 2:30 p.m. CET. Information and accreditation request at this link:

Related links:

ClearSpace SA:

École Polytechnique Fédérale de Lausanne (EPFL):



Images, Animations, Text, Credits: ESA/ClearSpace/CNES/Arianespace/Optique Video du CSG/ Aerospace/Roland Berga.


mercredi 25 novembre 2020

Дебютанты открытого космоса / Open space debutants


ROSCOSMOS patch / Russian Cosmonaut patch.

Nov. 25, 2020

русский / Russian:


18 ноября 2020 года космонавты Роскосмоса Сергей Рыжиков и Сергей Кудь-Сверчков в рамках подготовки к запуску и последующей стыковке лабораторного модуля «Наука» выполнили 47-й плановый выход в открытый космос по российской программе Международной космической станции. Продолжительность внекорабельной деятельности составила 6 часов 47 минут.

Космонавты Роскосмоса также заменили планшет эксперимента «Импакт» по изучению влияния выбросов из сопел двигателей ориентации служебного модуля «Звезда». И ближе к концу своей работы за бортом Сергей Рыжиков и Сергей Кудь-Сверчков повернули блок давления и осаждений, который установлен на малом исследовательском модуле.

Для обоих космонавтов это был первый выход в открытый космос в карьере. Работы по внекорабельной деятельности они выполняли в новых скафандрах «Орлан-МКС», один из них с красными лампасами (Рыжиков), другой — с синими (Кудь-Сверчков). Сегодня космонавт Роскосмоса Сергей Кудь-Сверчков опубликовал на своей официальной странице ВКонтакте уникальные фотографии из открытого космоса.

«На что же похожа работа за бортом? Конечно, работа снаружи очень сильно похожа на наши тренировки в гидролаборатории, — отмечает Сергей Кудь-Сверчков. — Тяжелый скафандр массой 120 кг и передвижение только на руках. Мне лично передвижение по поручням напомнило восхождения в горах, когда ты находишься на большой высоте, двигаешься по веревкам (или без них), перестёгиваешься, думая о точках страховки и ключевых точках маршрута. Шаг за шагом, плавно, но без остановок, а когда наступала тень, то в памяти ясно всплывали картинки уже из спелеоэкспедиций или кейв-дайвинга: ничего не видно, кроме снаряжения и окружающего пространства, попадающего в пятно фонарей. Внутренние ощущения были знакомы и уже не вызывали удивления или дискомфорта».

English / английский:

On November 18, 2020, Roscosmos cosmonauts Sergei Ryzhikov and Sergei Kud-Sverchkov, in preparation for the launch and subsequent docking of the Nauka laboratory module, performed the 47th planned spacewalk under the Russian program of the International Space Station. The duration of the extravehicular activity was 6 hours 47 minutes.

Roscosmos cosmonauts also replaced the tablet of the Impact experiment to study the effect of emissions from the nozzles of the orientation engines of the Zvezda service module. And towards the end of their work overboard, Sergei Ryzhikov and Sergei Kud-Sverchkov turned the pressure and deposition unit, which is installed on the small research module.

For both astronauts, this was the first spacewalk in their careers. They performed work on extravehicular activities in new Orlan-ISS spacesuits, one with red stripes (Ryzhikov), the other with blue stripes (Kud-Sverchkov). Today Roskosmos cosmonaut Sergei Kud-Sverchkov published unique photographs from outer space on his official VKontakte page.

“What is working overboard like? Of course, working outside is very much like our training in the hydro laboratory, - says Sergey Kud-Sverchkov. - A heavy spacesuit weighing 120 kg and moving only by hand. For me personally, moving on the handrails reminded me of climbing in the mountains, when you are at a high altitude, move along the ropes (or without them), change the harness, thinking about belay points and key points of the route. Step by step, smoothly, but without stopping, and when the shadow came, the pictures from speleo expeditions or cave diving clearly popped up in my memory: nothing was visible except the equipment and the surrounding space that fell into the spot of the lanterns. Internal sensations were familiar and no longer caused surprise or discomfort. "

Related articles:

Cosmonauts Wrap Up Spacewalk at Station

Cosmonauts Begin Spacewalk to Ready Station for New Module

Related links:


ROSCOSMOS Press Release:

Images, Text, Credits: ROSCOSMOS/ Aerospace/Roland Berga.

Best regards / С уважением,