mercredi 28 octobre 2020

More Space Physics and Human Research Aboard Station Today


ISS - Expedition 64 Mission patch.

October 28, 2020

The Expedition 64 crew continued this week’s run of space physics and human research aboard the International Space Station today. The orbital trio also spent the day servicing laptop computers and life support systems.

During Wednesday morning, Flight Engineer Kate Rubins of NASA installed material samples inside the Handhold Experiment Platform (HXP) that will soon be exposed to the harsh environment of space. She then placed the Japanese external experiment platform inside the Kibo laboratory module’s airlock. From there the Japanese robotic arm will grapple the HXP with the samples inside and install it outside Kibo. Scientists observe the materials over time to understand how space radiation and extreme temperatures affect a variety of samples, impacting the design of future spacecraft and advanced materials.

Image above: The Canadarm2 robotic arm is extended near the Northrop Grumman Cygnus resupply ship with its prominent cymbal-shaped UltraFlex solar arrays. Image Credit: NASA.

Rubins then moved onto fluid physics during the afternoon, setting up hardware for the Drop Vibration experiment. Engineers may be able to take advantage of the results to design advanced fuel, water, and air systems on spacecraft.

Flight Engineer Sergey Kud-Sverchkov of Roscosmos began wrapping up operations for a Russian immune system study. After collecting his saliva samples, he stowed the experiment’s hardware and transferred science data for later analysis. He also participated in a space exercise study to maintain a crew member’s health during long-term missions.

International Space Station (ISS). Animation Credits: NASA

During the morning, Commander Sergey Ryzhikov took part in the same exercise study as his fellow cosmonaut. The veteran cosmonaut then explored ways to improve interactions among international crews and mission control teams. Ryzhikov also upgraded software on a variety of laptop computers and checked airflow sensors throughout orbiting lab’s Russian segment.

Related links:

Expedition 64:

Handhold Experiment Platform (HXP):

Kibo laboratory module:

Drop Vibration:

Immune system study:

Space exercise study:

Improve interactions:

Space Station Research and Technology:

International Space Station (ISS):

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

Best regards,

Philae’s second touchdown site discovered at ‘skull-top’ ridge


ESA - Rosetta Mission patch.

Oct. 28, 2020

After years of detective work, the second touchdown site of Rosetta’s Philae lander has been located on Comet 67P/Churyumov-Gerasimenko in a site that resembles the shape of a skull. Philae left its imprint in billions-of-years-old ice, revealing that the comet’s icy interior is softer than cappuccino froth.

How Philae arrived at Skull Face

Detective story

Philae descended to the surface of the comet on 12 November 2014. It rebounded from its initial touchdown site at Agilkia and embarked on a two-hour flight, during which it collided with a cliff edge and tumbled towards a second touchdown location. Philae eventually came to a halt at Abydos, in a sheltered spot that was only identified in Rosetta imagery 22 months later, a few weeks before the conclusion of the Rosetta mission.

ESA’s Laurence O’Rourke, who played the leading role in finding Philae in the first instance, was also determined to locate the previously undiscovered second touchdown site.

Philae creates eye of the skull

“Philae had left us with one final mystery waiting to be solved,” says Laurence. “It was important to find the touchdown site because sensors on Philae indicated that it had dug into the surface, most likely exposing the primitive ice hidden underneath, which would give us invaluable access to billions-of-years-old ice.”

Together with a team of mission scientists and engineers, he set about pulling together data from both Rosetta and Philae instruments to find and confirm the ‘missing’ touchdown site.

How Philae left its mark during touchdown two

The star of the show

Although a bright patch of ‘sliced ice’ observed in high-resolution images from Rosetta’s OSIRIS camera proved crucial in confirming the location, it was Philae’s magnetometer boom, ROMAP, that turned out to be the star of the show. The instrument was designed to make magnetic field measurements in the comet’s local environment, but for the new analysis the team looked at changes recorded in the data that arose when the boom – which sticks out 48 cm from the lander – physically moved as it struck a surface. This created a characteristic set of spikes in the magnetic data as the boom moved relative to the lander body, which provided an estimate of the duration of Philae stamping into the ice. The data could also be used to constrain the acceleration of Philae during these contacts.

Philae’s dance at touchdown two

ROMAP’s data were cross-correlated with those collected by Rosetta’s RPC magnetometer at the same time to determine Philae’s attitude and exclude any influence from the background magnetic field of the plasma environment around the comet.

“We weren’t able to make all the measurements we planned in 2014 with Philae, so it is really amazing to use the magnetometer like this, and to combine data from both Rosetta and Philae in a way that was never intended, to give us these wonderful results,” says Philip Heinisch, who led the analysis of the ROMAP data.

A reanalysis of the touchdown data found that Philae had spent nearly two full minutes at the second touchdown site, making at least four distinct surface contacts as it ploughed across it. One particularly notable imprint revealed in the images was created as Philae’s top surface sank 25 cm into the ice on the side of a crevice, leaving identifiable marks of its drill tower and sides. The spikes in the magnetic field data arising from the boom movement showed that it took Philae three seconds to make this particular depression.

Where is ‘skull face’?

Skull face

“The shape of the boulders impacted by Philae reminded me of a skull when viewed from above, so I decided to nickname the region ‘skull-top ridge’ and to continue that theme for other features observed,” says Laurence.

“The right ‘eye’ of the ‘skull face’ was made by Philae’s top surface compressing the dust while the gap between the boulders is ‘skull-top crevice’, where Philae acted like a windmill to pass between them.”

A light shining in the darkness

Analysis of images and data from OSIRIS and Rosetta’s spectrometer VIRTIS confirmed that the bright exposure was water-ice covering an area of about 3.5 square metres. Although the ice was mostly in shadow at the time of the landing, the Sun was directly illuminating the area when the images were taken months later, lighting it up like a beacon to stand out against everything around it. The ice was brighter than the surrounds because it had not been previously exposed to the space environment and undergone space weathering.

“It was a light shining in the darkness,” says Laurence, noting that it was located just 30 m away from where Philae was finally imaged on the comet surface.

Interactive tour

Cappuccino froth

While an exciting conclusion in the search for the second touchdown site, the study also provides the first in situ measurement of the softness of the icy-dust interior of a boulder on a comet.

 “The simple action of Philae stamping into the side of the crevice allowed us to work out that this ancient, billions-of-years-old, icy-dust mixture is extraordinarily soft – fluffier than froth on a cappuccino, or the foam found in a bubble bath or on top of waves at the seashore,” adds Laurence.

The study also allowed an estimate of the boulder’s porosity – how much empty space exists between the ice-dust grains inside the boulder – of about 75%, which is in line with the value measured previously for the whole comet in a separate study. The same study showed that the comet is homogeneous anywhere in its interior on all size scales down to about one metre. This implies that the boulders represent the overall state of the comet’s interior when it formed some 4.5 billion years ago.

“This is a fantastic multi-instrument result that not only fills in the gaps in the story of Philae’s bouncy journey, but also informs us about the nature of the comet,” says Matt Taylor, ESA’s Rosetta project scientist. “In particular, understanding the strength of a comet is critical for future lander missions. That the comet has such a fluffy interior is really valuable information in terms of how to design the landing mechanisms, and also for the mechanical processes that might be needed to retrieve samples.”

Flight over Abydos valley

The Philae lander reveals low-strength primitive ice inside cometary boulders,” by O’Rourke et al is published in the journal Nature.

The study used data from Rosetta’s OSIRIS, VIRTIS and RPC-MAG instruments, and from Philae’s ROMAP instrument. Data from Rosetta’s MIRO instrument was also investigated but the instrument footprint was too wide to be able to draw conclusive statements for this study. ‘Shape models’ detailing the topography of the region in higher resolution than had been previously available at the time of landing were essential in gaining a 3D perspective on the region, as was new modelling of Philae’s flight trajectory.

Philae touchdown sites in context

Reanalysis of the ROMAP data shows that the initial contact at touchdown two occurred at 17:23:48 GMT, approximately 1.5 minutes earlier than previously reported. The originally reported time corresponds to the most significant contact made by Philae with the surface, but it is now apparent that Philae struck the surface multiple times during the second touchdown event, and spent around two minutes there.

Related links:

NATURE - “The Philae lander reveals low-strength primitive ice inside cometary boulders,”:


Rosetta’s RPC magnetometer:




Images, Animations, Videos, Text, Credits: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA; Data: ESA/Rosetta/Philae/ROMAP; Analysis: O’Rourke et al (2020).

Best regards,

mardi 27 octobre 2020

Physics, Biology Research Fill Station Schedule


ISS - Expedition 64 Mission patch.

Oct. 27, 2020

Physics and biology research filled the majority of the science schedule aboard the International Space Station today. The Expedition 64 crew also put on their technician caps and worked hardware, including life support gear and air conditioning systems.

NASA astronaut Kate Rubins swapped out sample containers Tuesday morning on an experiment platform that can be placed outside Japan’s Kibo laboratory module. Scientists use experiments installed on the outside of the station to understand how space radiation and extreme temperatures affect a variety of materials. Results may improve the design of future spacecraft and the production of stronger, safer materials on Earth.

Image abbove: NASA astronaut and Expedition 64 Flight Engineer Kate Rubins poses for a photograph with a variety of space research gear and science racks behind her. Image Credit: NASA.

Rubins then spent the afternoon working on hardware maintenance servicing life support hardware and science gear. She first swapped batteries and chips inside ammonia measurement kits, then installed a pair of portable science freezers inside the Kibo and U.S. Destiny lab modules.

Immune system studies continued throughout Tuesday in the Russian segment of the orbiting lab. Cosmonauts Sergey Ryzhikov and Sergey Kud-Sverchkov processed their own blood and saliva samples in the morning and evening to understand how spaceflight stresses the immunity of a crew member.

International Space Station (ISS). Image Credit: NASA

Ryzhikov, the station commander on his second space mission, also refilled freon bottles to maintain the orbiting lab’s air conditioning system. Kud-Sverchkov cleaned ventilation fans and filters before checking radiation readings and smoke detectors.

Related links:

Expedition 64:

Experiment platform:

Kibo laboratory module:

Portable science freezers:

Immune system:

Space Station Research and Technology:

International Space Station (ISS):

Images (mentioned), Text, Credits: NASA/Mark Garcia.

Best regards,

NASA Scientists Discover ‘Weird’ Molecule in Titan’s Atmosphere


NASA & ESA - Cassini-Huygens Mission to Saturn & Titan patch.

Oct. 27, 2020

NASA scientists identified a molecule in Titan’s atmosphere that has never been detected in any other atmosphere. In fact, many chemists have probably barely heard of it or know how to pronounce it: cyclopropenylidene, or C3H2. Scientists say that this simple carbon-based molecule may be a precursor to more complex compounds that could form or feed possible life on Titan.

Image above: These infrared images of Saturn's moon Titan represent some of the clearest global views of the icy moon's surface. The views were created using 13 years of data acquired by the Visual and Infrared Mapping Spectrometer instrument onboard NASA's Cassini spacecraft. Image Credits: NASA/JPL-Caltech/University of Nantes/University of Arizona.

Researchers found C3H2 by using a radio telescope observatory in northern Chile known as the Atacama Large Millimeter/submillimeter Array (ALMA). They noticed C3H2, which is made of carbon and hydrogen, while sifting through a spectrum of unique light signatures collected by the telescope; these revealed the chemical makeup of Titan’s atmosphere by the energy its molecules emitted or absorbed.

“When I realized I was looking at cyclopropenylidene, my first thought was, ‘Well, this is really unexpected,’” said Conor Nixon, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who led the ALMA search. His team’s findings were published on October 15 in the Astronomical Journal.

Though scientists have found C3H2 in pockets throughout the galaxy, finding it in an atmosphere was a surprise. That’s because cyclopropenylidene can react easily with other molecules it comes into contact with and form different species. Astronomers have so far found C3H2 only in clouds of gas and dust that float between star systems — in other words, regions too cold and diffuse to facilitate many chemical reactions.

Image above: This image was returned January 14, 2005 by the European Space Agency's Huygens probe during its successful descent to Titan's surface. This is the colored view that's been processed to add reflection spectra data to give better indication of the actual color of Titan's surface. Image Credits: NASA/JPL/ESA/University of Arizona.

But dense atmospheres like Titan’s are hives of chemical activity. That’s a major reason scientists are interested in this moon, which is the destination of NASA’s forthcoming Dragonfly mission. Nixon’s team was able to identify small amounts of C3H2 at Titan likely because they were looking in the upper layers of the moon’s atmosphere, where there are fewer other gases for C3H2 to interact with. Scientists don’t yet know why cyclopropenylidene would show up in Titan’s atmosphere but no other atmosphere. “Titan is unique in our solar system,” Nixon said. “It has proved to be a treasure trove of new molecules.”

The largest of Saturn’s 62 moons, Titan is an intriguing world that’s in some ways the most similar one to Earth we have found. Unlike any other moon in the solar system — there are more than 200 — Titan has a thick atmosphere that’s four times denser than Earth’s, plus clouds, rain, lakes and rivers, and even a subsurface ocean of salty water.

Titan’s atmosphere is made mostly of nitrogen, like Earth’s, with a hint of methane. When methane and nitrogen molecules break apart under the glare of the Sun, their component atoms unleash a complex web of organic chemistry that has captivated scientists and thrust this moon to the top of the list of the most important targets in NASA’s search for present or past life in the solar system.

“We’re trying to figure out if Titan is habitable,” said Rosaly Lopes, a senior research scientist and Titan expert at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California. “So we want to know what compounds from the atmosphere get to the surface, and then, whether that material can get through the ice crust to the ocean below, because we think the ocean is where the habitable conditions are.”

The types of molecules that might be sitting on Titan’s surface could be the same ones that formed the building blocks of life on Earth. Early in its history, 3.8 to 2.5 billion years ago, when methane filled Earth’s air instead of oxygen, conditions here could have been similar to those on Titan today, scientists suspect.

“We think of Titan as a real-life laboratory where we can see similar chemistry to that of ancient Earth when life was taking hold here,” said Melissa Trainer, a NASA Goddard astrobiologist. Trainer is the Dragonfly mission’s deputy principal investigator and lead of an instrument on the Dragonfly rotorcraft that will analyze the composition of Titan’s surface.

“We’ll be looking for bigger molecules than C3H2,” Trainer said, “but we need to know what’s happening in the atmosphere to understand the chemical reactions that lead complex organic molecules to form and rain down to the surface.

The Science of Dragonfly

Video above: Dragonfly is a NASA mission that aims to explore the chemistry and habitability of Saturn's largest moon, Titan. Video Credits: NASA's Goddard Space Flight Center/Johns Hopkins University Applied Physics Laboratory.

Cyclopropenylidene is the only other “cyclic,” or closed-loop, molecule besides benzene to have been found in Titan’s atmosphere so far. Although C3H2 is not known to be used in modern-day biological reactions, closed-loop molecules like it are important because they form the backbone rings for the nucleobases of DNA, the complex chemical structure that carries the genetic code of life, and RNA, another critical compound for life’s functions. “The cyclic nature of them opens up this extra branch of chemistry that allows you to build these biologically important molecules,” said Alexander Thelen, a Goddard astrobiologist who worked with Nixon to find C3H2.

Scientists like Thelen and Nixon are using large and highly sensitive Earth-based telescopes to look for the simplest life-related carbon molecules they can find in Titan’s atmosphere. Benzene was considered to be the smallest unit of complex, ringed hydrocarbon molecules found in any planetary atmosphere. But now, C3H2, with half the carbon atoms of benzene, appears to have taken its place.

Nixon's team used the ALMA observatory to peer at Titan in 2016. They were surprised to find a strange chemical fingerprint, which Nixon identified as cyclopropenylidene by searching through a database of all known molecular light signatures.

Image above: Until now, cyclopropenylidene has been detected only in molecular clouds of gas and dust, such as the Taurus Molecular Cloud, which is a stellar nursery in the constellation Taurus more than 400 light years away. Recently, NASA Goddard scientist Conor Nixon, along with his team, found this unique molecule in Titan’s atmosphere; the first time it has been detected outside of a molecular cloud. Cyclopropenylidene is the only other closed-loop molecule besides benzene to have been detected at Titan. Closed-loop molecules are important because they form the backbone rings for the nucleobases of DNA, the complex chemical structure that carries the genetic code of life, and RNA, another critical compound for life’s functions. Image Credits: Conor Nixon/NASA's Goddard Space Flight Center.

To double check that the researchers were actually seeing this unusual compound, Nixon pored through research papers published from analyses of data from NASA’s Cassini spacecraft, which made 127 close flybys of Titan between 2004 and 2017. He wanted to see if an instrument on the spacecraft that sniffed out the chemical compounds around Saturn and Titan could confirm his new result. (The instrument – called a mass spectrometer – picked up hints of many mysterious molecules at Titan that scientists are still trying to identify.) Indeed, Cassini had spotted evidence for an electrically charged version of the same molecule, C3H2+.

Given that it’s a rare find, scientists are trying to learn more about cyclopropenylidene and how it might interact with gases in Titan’s atmosphere.

“It’s a very weird little molecule, so it’s not going be the kind you learn about in high school chemistry or even undergraduate chemistry,” said Michael Malaska, a JPL planetary scientist who worked in the pharmaceutical industry before falling in love with Titan and switching careers to study it. “Down here on Earth, it’s not going be something you’re going to encounter.”

But, Malaska said, finding molecules like C3H2 is really important in seeing the big picture of Titan: “Every little piece and part you can discover can help you put together the huge puzzle of all the things going on there.”

Related links:

Dragonfly rotorcraft:

Dragonfly mission:

Astronomical Journal:

Atacama Large Millimeter/submillimeter Array (ALMA):


Images (mentioned), Video (mentioned), Text, Credits: NASA/Svetlana Shekhtman/GSFC, by Lonnie Shekhtman.


NASA's Perseverance Rover Is Midway to Mars


NASA - Mars 2020 Perseverance Rover logo.

Oct. 27, 2020

Sometimes half measures can be a good thing - especially on a journey this long. The agency's latest rover only has about 146 million miles left to reach its destination.

Image above: This illustration of the Mars 2020 spacecraft in interplanetary space was generated using imagery from NASA's Eyes on the Solar System. The image is from the mission's midway point between Earth and Mars. Image credits: NASA/JPL-Caltech.

NASA's Mars 2020 Perseverance rover mission has logged a lot of flight miles since being lofted skyward on July 30 - 146.3 million miles (235.4 million kilometers) to be exact. Turns out that is exactly the same distance it has to go before the spacecraft hits the Red Planet's atmosphere like a 11,900 mph (19,000 kph) freight train on Feb. 18, 2021.

"At 1:40 p.m. Pacific Time today, our spacecraft will have just as many miles in its metaphorical rearview mirror as it will out its metaphorical windshield," said Julie Kangas, a navigator working on the Perseverance rover mission at NASA's Jet Propulsion Laboratory in Southern California. "While I don't think there will be cake, especially since most of us are working from home, it's still a pretty neat milestone. Next stop, Jezero Crater."

The Sun's gravitational influence plays a significant role in shaping not just spacecraft trajectories to Mars (as well as to everywhere else in the solar system), but also the relative movement of the two planets. So Perseverance's route to the Red Planet follows a curved trajectory rather than an arrow-straight path.

Image above: NASA's Mars 2020 Perseverance rover reached its halfway point - 146.3 million miles (235.4 million kilometers) - on its journey to Jezero Crater on Oct. 27, 2020, at 1:40 p.m. PDT (4:40 EDT). Image Credits: NASA/JPL-Caltech.

"Although we're halfway into the distance we need to travel to Mars, the rover is not halfway between the two worlds," Kangas explained. "In straight-line distance, Earth is 26.6 million miles [42.7 million kilometers] behind Perseverance and Mars is 17.9 million miles [28.8 million kilometers] in front."

At the current distance, it takes 2 minutes, 22 seconds for a transmission to travel from mission controllers at JPL via the Deep Space Network to the spacecraft. By time of landing, Perseverance will have covered 292.5 million miles (470.8 million kilometers), andMars will be about 130 million miles (209 million kilometers) away from Earth; at that point, a transmission will take about 11.5 minutes to reach the spacecraft.

Work Continues En Route

The mission team continues to check out spacecraft systems big and small during interplanetary cruise. Perseverance's RIMFAX and MOXIE instruments were tested and determined to be in good shape on Oct. 15. MEDA got a thumbs up on Oct. 19. There was even a line item to check the condition of the X-ray tube in the PIXL instrument on Oct. 16, which also went as planned.

Mars 2020 Perseverance Rover on the way to Mars. Animation Credit: NASA

"If it is part of our spacecraft and electricity runs through it, we want to confirm it is still working properly following launch," said Keith Comeaux, deputy chief engineer for the Mars 2020 Perseverance rover mission. "Between these checkouts - along with charging the rover's and Mars Helicopter's batteries, uploading files and sequences for surface operations, and planning for and executing trajectory correction maneuvers - our plate is full right up to landing."

More About the Mission

A key objective of Perseverance's mission on Mars is astrobiology, including the search for signs of ancient microbial life. The rover will characterize the planet's geology and past climate, pave the way for human exploration of the Red Planet, and be the first mission to collect and cache Martian rock and regolith (broken rock and dust).

Subsequent missions, currently under consideration by NASA in cooperation with ESA (European Space Agency), would send spacecraft to Mars to collect these cached samples from the surface and return them to Earth for in-depth analysis.

The Mars 2020 mission is part of a larger program that includes missions to the Moon as a way to prepare for human exploration of the Red Planet. Charged with returning astronauts to the Moon by 2024, NASA will establish a sustained human presence on and around the Moon by 2028 through NASA's Artemis lunar exploration plans:

JPL, which is managed for NASA by Caltech in Pasadena, California, built and manages operations of the Perseverance and Curiosity rovers.

For more about Perseverance:

For more information about NASA's Mars missions, go to:

Related link:

Deep Space Network (DSN):

Images (mentioned), Animation (mentioned), Text, Credits: NASA/Grey Hautaluoma/Alana Johnson/JPL/DC Agle.

Best regards,

Greenland's Retreating Glaciers Could Impact Local Ecology


NASA logo.

Oct. 27, 2020

Details about the physical transformation of over 200 of the island's coastal glaciers are documented in a new study, in which the authors anticipate environmental impacts.

Image above: Greenland appears in this image created using data from the ITS_LIVE project, hosted at NASA's Jet Propulsion Laboratory. The coloring around the coast of the arctic island shows the speed of outlet glaciers flowing into the ocean. Image Credits: NASA/JPL-Caltech/USGS.

A new study of Greenland's shrinking ice sheet reveals that many of the island's glaciers are not only retreating, but are also undergoing other physical changes. Some of those changes are causing the rerouting of freshwater rivers beneath the glaciers, where it meets the bedrock. These rivers carry nutrients into the ocean, so this reconfiguring has the potential to impact the local ecology as well as the human communities that depend on it.

"The coastal environment in Greenland is undergoing a major transformation," said Alex Gardner, a research scientist at NASA's Jet Propulsion Laboratory and co-author of the study. "We are already seeing new sections of the ocean and fjords opening up as the ice sheet retreats, and now we have evidence of changes to these freshwater flows. So losing ice is not just about changing sea level, it's also about reshaping Greenland's coastline and altering the coastal ecology."

Image above: This data visualization shows the flow velocity of glaciers along Greenland's coast. White represents the slowest-flow regions; light blue shows slightly faster regions, followed by shades of blue, then green and red. The fastest-moving regions are magenta. Image Credits: NASA/JPL-Caltech/USGS.

About 80% of Greenland is blanketed by an ice sheet, also known as a continental glacier, that reaches a thickness of up to 2.1 miles (3.4 kilometers). Multiple studies have shown that the melting ice sheet is losing mass at an accelerating rate due to rising atmosphere and ocean temperatures, and that the additional meltwater is flowing into the sea.

This study, published on Oct. 27 in the Journal of Geophysical Research: Earth's Surface, provides a detailed look at physical changes to 225 of Greenland's ocean-terminating glaciers, which are narrow fingers of ice that flow from the ice sheet interior out into the ocean. The data used in the paper was compiled as part of a project based at JPL called Inter-mission Time Series of Land Ice Velocity and Elevation, or ITS_LIVE, which brings together observations of glaciers around the globe - collected by multiple satellites between 1985 and 2015 - into a single dataset open to scientists and the public. The satellites are all part of the Landsat program, which has sent a total of seven spacecraft into orbit to study Earth's surface since 1972. Managed by NASA and the U.S. Geological Survey, Landsat data reveals both natural and human-caused changes to Earth's surface, and is used by land managers and policymakers to make decisions about Earth's changing environment and natural resources.

Animation above: Glacier flow is imperceptible to the human eye, but this animation shows glaciers in Asia moving over a span of 11 years, from 1991 to 2002. The animation is composed of false-color images from Landsat 5 and 7 spacecraft. Moving ice is gray and blue; brighter blues are changing snow and ice cover. Animation Credits: NASA/JPL-Caltech/USGS/Earth Observatory.

Advancing and Retreating

As glaciers flow toward the sea - albeit too slowly to be perceptible to the eye - they are replenished by new snowfall on the interior of the ice sheet that gets compacted into ice. Some glaciers extend past the coastline and can break off as icebergs. Due to rising atmospheric and ocean temperatures, the balance between glacier melting and replenishment, as well as iceberg calving, is changing. Over time, a glacier's front may naturally advance or retreat, but the new research shows that none of the 225 ocean-terminating glaciers surveyed has substantially advanced since 2000, while 200 have retreated.

Although this is in line with other Greenland findings, the new survey captures a trend that hasn't been apparent in previous work: As individual glaciers retreat, they are also changing in ways that are likely rerouting freshwater flows under the ice. For example, glaciers change in thickness not only as warmer air melts ice off their surfaces, but also as their flow speed changes in response to the ice front advancing or retreating.

Both scenarios were observed in the new study, and both can lead to changes in the distribution of pressure beneath the ice; scientists can infer these pressure changes based on changes in thickness analyzed in the study. This, in turn, can change the path of a subglacial river, since water will always take the path of least resistance, flowing in the direction of lowest pressure.

Citing previous studies on the ecology of Greenland, the authors note that freshwater rivers under the ice sheet deliver nutrients (such as nitrogen, phosphorus, iron, and silica) to bays, deltas, and fjords around Greenland. In addition, the under-ice rivers enter the ocean where the ice and bedrock meet, which is often well below the ocean's surface. The relatively buoyant fresh water rises, carrying nutrient-rich deep ocean water to the surface, where the nutrients can be consumed by phytoplankton. Research has shown that glacial meltwater rivers directly impact the productivity of phytoplankton - meaning the amount of biomass they produce - which serves as a foundation of the marine food chain. Combined with the opening up of new fjords and sections of ocean as glaciers retreat, these changes amount to a transformation of the local environment.

"The speed of ice loss in Greenland is stunning," said Twila Moon, deputy lead scientist of the National Snow and Ice Data Center and lead author on the study. "As the ice sheet edge responds to rapid ice loss, the character and behavior of the system as a whole are changing, with the potential to influence ecosystems and people who depend on them."

The changes described in the new study seem to depend on the unique features of its environment, such as the slope of the land that the glacier flows down, the properties of the ocean water that touch the glacier, as well as the glacier's interaction with neighboring glaciers. That suggests scientists would need detailed knowledge not only of the glacier itself, but also of the glacier's unique environment in order to predict how it will respond to continued ice loss.

"It makes modeling glacial evolution far more complex when we're trying to anticipate how these systems will evolve both in the short term and two or three decades out," Gardner said. "It's going to be more challenging than we previously thought, but we now have a better understanding of the processes driving the variety of responses, which will help us make better ice sheet models."

Related links:

Journal of Geophysical Research:


Images (mentioned), Animation (mentioned), Text, Credits: NASA/JPL/Jane J. Lee/Calla Cofield.


Juno Data Indicates 'Sprites' or 'Elves' Frolic in Jupiter's Atmosphere


NASA - JUNO Mission logo.

Oct. 27, 2020

An instrument on the spacecraft may have detected transient luminous events - bright flashes of light in the gas giant's upper atmosphere.

Image above: The lightning phenomenon known as a sprite depicted at Jupiter in this illustration. Jupiter's hydrogen-rich atmosphere would likely make them appear blue. In Earth's upper atmosphere, the presence of nitrogen gives them a reddish color. Image Credits: NASA/JPL-Caltech/SwRI.

New results from NASA's Juno mission at Jupiter suggest that either "sprites" or "elves" could be dancing in the upper atmosphere of the solar system's largest planet. It is the first time these bright, unpredictable and extremely brief flashes of light - formally known as transient luminous events, or TLE's - have been observed on another world. The findings were published on Oct. 27, 2020, in the Journal of Geophysical Research: Planets.

Scientists predicted these bright, superfast flashes of light should also be present in Jupiter's immense roiling atmosphere, but their existence remained theoretical. Then, in the summer of 2019, researchers working with data from Juno's ultraviolet spectrograph instrument (UVS) discovered something unexpected: a bright, narrow streak of ultraviolet emission that disappeared in a flash.

Image above: The south pole of Jupiter and a potential transient luminous event - a bright, unpredictable, and extremely brief flash of light - is seen in this annotated image of data acquired on April 10, 2020, from Juno's UVS instrument. Image Credits: NASA/JPL-Caltech/SwRI.

"UVS was designed to characterize Jupiter's beautiful northern and southern lights," said Giles, a Juno scientist and the lead author of the paper. "But we discovered UVS images that not only showed Jovian aurora, but also a bright flash of UV light over in the corner where it wasn't supposed to be. The more our team looked into it, the more we realized Juno may have detected a TLE on Jupiter."

Brief and Brilliant

Named after a mischievous, quick-witted character in English folklore, sprites are transient luminous events triggered by lightning discharges from thunderstorms far below. On Earth, they occur up to 60 miles (97 kilometers) above intense, towering thunderstorms and brighten a region of the sky tens of miles across, yet last only a few milliseconds (a fraction of the time it takes you to blink an eye).

Almost resembling a jellyfish, sprites feature a central blob of light (on Earth, it's 15 to 30 miles, or 24 to 48 kilometers, across), with long tendrils extending both down toward the ground and upward. Elves (short for Emission of Light and Very Low Frequency perturbations due to Electromagnetic Pulse Sources) appear as a flattened disk glowing in Earth's upper atmosphere. They, too, brighten the sky for mere milliseconds but can grow larger than sprites - up to 200 miles (320 kilometers) across on Earth.

Their colors are distinctive as well. "On Earth, sprites and elves appear reddish in color due to their interaction with nitrogen in the upper atmosphere," said Giles. "But on Jupiter, the upper atmosphere mostly consists of hydrogen, so they would likely appear either blue or pink."

JUNO spacecraft orbiting Jupiter. Animation Credit: NASA

Location, Location, Location

The occurrence of sprites and elves at Jupiter was predicted by several previously published studies. Synching with these predictions, the 11 large-scale bright events Juno's UVS instrument has detected occurred in a region where lightning thunderstorms are known to form. Juno scientists could also rule out that these were simply mega-bolts of lightning because they were found about 186 miles (300 kilometers) above the altitude where the majority of Jupiter's lightning forms - its water-cloud layer. And UVS recorded that the spectra of the bright flashes were dominated by hydrogen emissions.

A rotating, solar-powered spacecraft, Juno, arrived at Jupiter in 2016 after making a five-year journey. Since then, it has made 29 science flybys of the gas giant, each orbit taking 53 days.

"We're continuing to look for more telltale signs of elves and sprites every time Juno does a science pass," said Giles. "Now that we know what we are looking for, it will be easier to find them at Jupiter and on other planets. And comparing sprites and elves from Jupiter with those here on Earth will help us better understand electrical activity in planetary atmospheres."

More About the Mission

JPL, a division of Caltech in Pasadena, California, manages the Juno mission for the principal investigator, Scott Bolton, of the Southwest Research Institute in San Antonio. Juno is part of NASA's New Frontiers Program, which is managed at NASA's Marshall Space Flight Center in Huntsville, Alabama, for the agency's Science Mission Directorate in Washington. Lockheed Martin Space in Denver built and operates the spacecraft.

More information about Juno is available at:

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Images (mentioned), Animation (mentioned), Text, Credits: NASA/Alana Johnson/JPL/DC Agle/Southwest Research Institute/Deb Schmid.


ESA seeking dust-proof materials for lunar return


ESA - European Astronauts patch.

Oct. 27, 2020

When humans return to the Moon they’ll have formidable challenge lying in wait: lunar dust. The talcum-like lunar regolith is considered the biggest operational problem facing Moon colonists. Within a few days of dust exposure, Apollo spacesuits suffered obscured visors, clogged mechanisms and eroded suit layers. So an ESA team is looking into novel material options to serve as the basis of future spacesuits or protect rovers or fixed infrastructure.

“The idea came up that as ESA’s going back to the Moon we should look into harnessing the many innovations in the materials field since the Apollo spacesuits were designed, more than half a century ago,” remarks ESA materials and processes engineer Malgorzata Holynska.

Lunar dust clinging to spacesuit

“So while we are not developing a new spacesuit at this time, we are looking into selecting candidate materials such a suit might use – as well as protective covers for rovers or fixed machinery and infrastructure – and performing some state-of-the-art testing to see how they stand up against simulated lunar conditions, particularly lunar dust.”

Moon of dust

As Apollo 12 Commander Pete Conrad noted: “I think probably one of the most aggravating, restricting facets of lunar surface exploration is the dust and its adherence to everything no matter what kind of material, whether it be skin, suit material, metal, no matter what it be and its restrictive friction-like action to everything it gets on.”

Dust-coated Apollo glove

That turned out to include spacesuits: “Suit integrities did stay good, but there’s no doubt in my mind that with a couple more EVA’s something could have ground to a halt. In the area where the lunar boots fitted on the suits, we wore through the outer garment and were beginning to wear through the Mylar.”

More recently, China’s Yutu-1 rover is believed to have been immobilized during its second day on the Moon by lunar dust clogging its moving parts.

Violent origins

Lunar dust is present all across the Moon, created by the steady bombardment of micrometeorites smashes the rocky surface into fine particles. Unlike terrestrial dust it has never been weathered by water or wind, so that even microscopic particles still maintain edges of razor sharpness. And the unfiltered energy of lunar sunshine can impart the dust with serious static cling.

Microscopic close-ups of simulated lunar dust

“Depending on its area of origin the dust might have very different chemical and abrasive characteristics, with its precise properties depending on the selected landing site – which is another factor of concern,” notes ESA structural engineer Shumit Das.

“One of the key findings from Apollo was that the abrasion effects of the lunar regolith would be the major limiting factor in returning to the Moon. We want to overcome that and enable spacesuits that could be used for many more spacewalks than the few performed per Apollo landing – up to 2 500 hours of surface activities is our assumption.”

Mechanical testing

ESA’s is overseeing the project, partnering with French human factors specialist Comex, the German Institutes for Textile and Fiber Research and citizen science organisation the Austrian Space Forum, which has a focus on spacesuit research.

Abrasion testing

A workshop was organised last year to meet with different materials providers, to gain insight into promising options based on the most recent advances.

Testing for lunar dress success

“No one material can really do the job,” adds Malgorzata. “Instead the concept is to have a layered solution, and define which combination of functional layers works best, in terms of physical and chemical interactions with regolith, and how to best connect them.

Comex working with design students on suit design

“We are then testing these different stacks against criteria contributed by our colleagues from ESA’s Directorate of Robotic and Human Exploration. The challenge here is to make the testing as robust as possible, to come up with credible results to guide our choice of trade-offs and downselection.”

The German Institutes for Textile and Fiber Research is performing the bulk of project testing.

Lunar soil simulant

“For instance, one abrasion test involves placing the test material into a tumbler with bricks of simulated lunar material, to see how it lasts over time – which has been adapted from an existing textile test standard,” adds Shumit.

“Classic permeability tests are also being undertaken, where a high-pressure fluid is applied to a material to see if it goes through. And a test chamber is in development intended for ‘thermal cycling’ – exposing material to repeated temperature extremes during vacuum condition.”

A lunar simulant called EAC-1A is employed for project testing, developed by ESA’s European Astronaut Centre in Germany, processed from volcanic soil.

From spacewalks to storage


The test regime is looking at the entire life cycle of any future spacesuits, also including storage time between spacewalks. Shumit explains: “Future suits would typically be stored on the Gateway in lunar orbit between surface EVAs. We need to know that suit seals, rubber or other elements would not be degraded by their time in storage, so that also include accelerated ageing tests, including moisture and radiation exposure.”

Supported through ESA’s Technology Development Element for promising new ideas, the project has been featured in the Advanced Materials Technologies journal.

Related links:

ESA’s Technology Development Element:

Advanced Materials Technologies journal:


ESA’s European Astronaut Centre:

China’s Yutu-1 rover:

Space Engineering & Technology:

Images, Text, Credits: ESA/NASA/Comex.

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Positive signs for Europe as ESA goes forward to the Moon


ESA - European Space Agency patch.

Oct. 27, 2020

ESA Director General Jan Wörner and NASA Administrator Jim Bridenstine have signed a Memorandum of Understanding (MoU) to take Europe to the Moon.

Gateway with Orion over Moon – alternative view

The historic agreement will see ESA Member States contribute a number of essential elements to the first human outpost in lunar orbit, known as the Gateway.

Gateway with Orion docking

It confirms ESA’s commitment to delivering at least two European Service Modules that provide electricity, water, oxygen and nitrogen to NASA’s Orion spacecraft – with more to come. ESA will also receive three flight opportunities for European astronauts to travel to and work on the Gateway.

Angelic halo orbit chosen for humankind’s first lunar outpost

The Gateway will enable sustainable exploration around – and on – the Moon, while enabling research and demonstrating the technologies and processes necessary to conduct a future mission to Mars. ESA’s contribution to this international endeavour under the MoU includes building the main habitat for astronauts when they visit the Gateway, known as I-Hab.

 The Gateway concept

A second contribution called ESPRIT, will supply enhanced communications, refuelling capability and a window, similar to the European-built Cupola observatory on the International Space Station. This is consistent with what was approved by Member States at ESA’s Space19+ Ministerial Council, in Seville, Spain, last year.

What is Esprit?

Though the MoU was signed remotely because of COVID-19 restrictions, ESA Director General Jan Wörner says ESA’s involvement with NASA’s Artemis programme has been many years in the making.

Human and Robotic Exploration destinations

“Throughout 20 years of continuous human presence on the International Space Station, we have seen an unparalleled level of cooperation between nations. Sustainable space exploration requires coordinated, international efforts and Europe has proven itself a strong and reliable partner,” he explains.

Signing ESA-NASA Gateway Memorandum of Understanding

“This MoU marks a critical point in Europe’s trajectory: it confirms we are going forward to the Moon, not just in terms of equipment and technology, but also with our people. Europe will play a central role in the new era of global space exploration along with NASA and our partners, delivering exemplary, game-changing architectures to explore the Moon and Mars and inspiring generations to come.”

Orion and European Service Module over the Moon

This sentiment is echoed by ESA Director of Human and Robotic Exploration David Parker. “ESA is honoured to be a strong partner of NASA for Artemis, extending the Space Station partnership forward to the Moon,” he says.

“Every launch of astronauts to the Moon aboard the new Orion spaceship will rely on the European Service Module for power, propulsion, oxygen and water. Europe will provide crew accommodation, telecommunications, refuelling and an amazing view of the Moon thanks to the ESA contributions to the lunar Gateway. And what is more, European astronauts will fly to the Gateway to live and work in deep space for the first time.

Overview of lunar missions with ESA involvement

This landmark signature was underlined by Marco Ferrazzani, Head of ESA Legal Services and the Agency’s lead negotiator for this MoU.

“This signature establishes the agreement between NASA and ESA of a genuine partnership for cooperation on a civil human outpost in the lunar vicinity, building on the wealth of experience gained through long cooperation together. For our future role in exploration it will have the same magnitude as the MoU for the International Space Station.

“The negotiation was supported by the tireless work of ESA Member States who, as with the International Space Station, collectively resolved to form a single European partner allowing for the start of this European endeavour in lunar exploration.”

Powered to the Moon

Find out more about ESA’s European vision for exploration over the next 10 years.

Related links:

ESA’s European vision for exploration:

NASA’s Artemis programme:

Human and Robotic Exploration:

Immages (mentioned), Video, Text, Credits: ESA/NASA/ATG Medialab.

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lundi 26 octobre 2020

Crew Studies Life Science Ahead of 20 Years Milestone


ISS - Expedition 64 Mission patch.

October 26, 2020

The Expedition 64 trio is nearing its second full week aboard the International Space Station and is beginning the work week with a host of biomedical studies today. The three station crew members will also bring in the 20th year of continuous human habitation of the orbital lab on Nov. 2.

Flight Engineers Kate Rubins and Sergey Kud-Sverchkov with Commander Sergey Ryzhikov started Monday collecting mass measurements before splitting up for the rest of the day. After waking up, they attached themselves to a device that applies a known force to a crew member and uses the resulting acceleration to calculate an astronaut’s mass in microgravity.

Image above: NASA astronaut and Expedition 64 Flight Engineer Kate Rubins points to the International Space Station’s “voting booth” where she cast her vote from space this month. Image Credit: NASA.

Rubins spent part of the day on lab maintenance tasks replacing water filters and collecting microbe samples from station surfaces for analysis. She then serviced and inspected an array of science hardware including a Japanese external experiment platform, fluid physics research gear and finally the Advanced Plant Habitat.

Ryzhikov then joined Kud-Sverchkov for a variety of studies exploring how their bodies are adapting to microgravity. The Russian duo logged their meals and drinks throughout the day for an investigation that seeks to understand bone loss in space. The pair also worked on an experiment to improve exercise techniques to sustain long-term space exploration missions. Kud-Sverchkov later collected and stowed his saliva samples for a study looking at how the human immune system adapts to microgravity.

Image above: NASA astronauts Shannon Walker, Victor Glover, and Mike Hopkins, and astronaut Soichi Noguchi of the Japan Aerospace Exploration Agency - who constitute the crew of NASA's Crew-1 mission - inside SpaceX's Crew Dragon spacecraft. Image Credit: SpaceX.

On Nov. 2, Rubins with fellow crewmates Ryzhikov and Kud-Sverchkov will be part of 20 years of humans continuously orbiting Earth aboard the station. They are the 64th long-term crew to live and work on the orbiting lab. The first crew to board the station was Expedition 1 on Nov. 2, 2000, with Commander William Shepherd of NASA with Roscosmos Flight Engineers Sergei Krikalev and Yuri Gidzenko.

Related article:

NASA, SpaceX Invite Media to Crew-1 Mission Update, Target New Launch Date

Related links:

Expedition 64:

External experiment platform:

Fluid physics research gear:

Advanced Plant Habitat:

Bone loss in space:

Improve exercise techniques:

Human immune system:

Expedition 1:

Space Station Research and Technology:

International Space Station (ISS):

Images (mentioned), Text, Credits: NASA/Mark Garcia.

Best regards,