четверг, 25 июля 2019 г.

Internal Strife Caused by parasites transmitted by biting…

Internal Strife

Caused by parasites transmitted by biting phlebotomine sand flies, leishmaniasis is a widespread disease with several forms, either leading to severe skin complaints or seriously damaging organs, especially the spleen and liver. Upon infection, white blood cells called macrophages engulf the Leishmania parasites. Yet, rather than being destroyed, the parasites thrive, reproducing within the macrophages, inside compartments known as vacuoles (as shown, in a 3D reconstruction based on microscopy images, with a macrophage in white and parasites in red). Recent research suggests this process involves host V-ATPases, complex proteins which control vacuolar pH by shuttling protons across compartment membranes, alongside many other functions. One part of these proteins in particular, upregulated by infection with Leishmania parasites, appears to be important: without it, vacuoles are smaller and parasites become vulnerable to the immune system’s inflammatory response. Interfering with this protein domain could thus open up new possibilities for tackling intracellular parasites.

Written by Emmanuelle Briolat

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Astronomers spy Europa blocking distant star – thanks to Gaia

ESA — Gaia Mission patch.

25 July 2019

On 31 March 2017, Jupiter’s moon Europa passed in front of a background star – a rare event that was captured for the first time by ground-based telescopes thanks to data provided by ESA’s Gaia spacecraft.

Gaia spacecraft

Previously, observatories had only managed to watch two of Jupiter’s other moons – Io and Ganymede – during such an event.

Gaia has been operating in space since late 2013. The mission aims to produce a three-dimensional map of our Galaxy, and characterise the myriad stars that call the Milky Way home. It has been immensely successful so far, revealing the locations and motions of over one billion stars.

Knowing the precise locations of the stars we see in the sky allows scientists to predict when various bodies in the Solar System will appear to pass in front of a background star from a given vantage point: an event known as a stellar occultation.

Jupiter’s largest moons

Gaia is no stranger to such events – the spacecraft helped astronomers make unique observations of Neptune’s moon Triton as it passed in front of a distant star in 2017, revealing more about the moon’s atmosphere and properties.

Occultations are hugely valuable; they enable measurements of the characteristics of the foreground body (size, shape, position, and more), and can reveal structures like rings, jets, and atmospheres. Such measurements can be made from the ground – something that Bruno Morgado of the Brazilian National Observatory and LIneA, Brazil, and colleagues took advantage of to explore Jupiter’s moon Europa.

“We used data from Gaia’s first data release to forecast that, from our viewpoint in South America, Europa would pass in front of a bright background star in March 2017 – and to predict the best location from which to observe this occultation,” said Bruno, lead researcher of a new paper reporting the findings from the 2017 occultation. Gaia’s first data release was provided in September 2016.

“This gave us a wonderful opportunity to explore Europa, as the technique offers an accuracy comparable to that of images obtained by space probes.”

The Gaia data showed that the event would be visible from a thick band slicing from north-west to south-east across South America. Three observatories located in Brazil and Chile were able to capture data – a total of eight sites attempted, but many experienced poor weather conditions.

In-keeping with previous measurements, the observations refined Europa’s radius to 1561.2 km, precisely determined Europa’s position in space and in relation to its host planet, Jupiter, and characterised the moon’s shape. Rather than being exactly spherical, Europa is known to be an ellipsoid. The observations show the moon to measure 1562 km when measured across in one direction (the so-called apparent ‘semi-major’ axis), and 1560.4 km when measured across the other (the apparent ‘semi-minor’ axis).

Upcoming stellar occultations by Jupiter’s four largest moons

“It’s likely that we’ll be able to observe far more occultations like this by Jupiter’s moons in 2019 and 2020,” adds Bruno. “Jupiter is passing through a patch of sky that has the galactic centre in the background, making it drastically more likely that its moons will pass in front of bright background stars. This would really help us to pin down their three-dimensional shapes and positions – not only for Jupiter’s four largest moons, but for smaller, more irregularly-shaped ones, too.”

Using Gaia’s second data release, provided in April 2018, the scientists predict the dates of further occultations of bright stars by Europa, Io, Ganymede and Callisto in coming years, and list a total of 10 events through 2019 and 2021. Future events comprise stellar occultations by Europa (22 June 2020), Callisto (20 June 2020, 4 May 2021), Io (9 and 21 September 2019, 2 April 2021), and Ganymede (25 April 2021).

Three have already taken place in 2019, two of which – stellar occultations by Europa (4 June) and Callisto (5 June) – were also observed by the researchers, and for which the data are still under analysis.

The upcoming occultations will be observable even with amateur telescopes as small as 20 cm from various regions around the world. The favourable position of Jupiter, with the galactic plane in the background, will only occur again in 2031.

Juice will fly by Europa during its tour of the Jovian system

“Stellar occultation studies allow us to learn about moons in the Solar System from afar, and are also relevant for future missions that will visit these worlds,” says Timo Prusti, ESA Gaia Project Scientist. “As this result shows, Gaia is a hugely versatile mission: it not only advances our knowledge of stars, but also of the Solar System more widely.”

An accurate knowledge of Europa’s orbit will help to prepare space missions targeting the Jovian system such as ESA’s JUpiter ICy moons Explorer (Juice) and NASA’s Europa Clipper, both of which are scheduled for launch in the next decade.

“These kinds of observations are hugely exciting,” says Olivier Witasse, ESA’s Juice Project Scientist. “Juice will reach Jupiter in 2029; having the best possible knowledge of the positions of the system’s moons will help us to prepare for the mission navigation and future data analysis, and plan all of the science we intend to do.

“This science depends upon us knowing things such as accurate moon trajectories and understanding how close a spacecraft will come to a given body, so the better our knowledge, the better this planning – and the subsequent data analysis – will be.”

Notes for editors:

“First stellar occultation by the Galilean moon Europa and upcoming events between 2019 and 2021” by B. Morgado et al. (2019), is published in Astronomy & Astrophysics. https://www.researchgate.net/publication/333487579_First_stellar_occultation_by_the_Galilean_moon_Europa_and_upcoming_events_between_2019_and_2021

Details of past and future stellar occultation observing campaigns for Jupiter’s moons and other Solar System objects will be listed here: http://lesia.obspm.fr/lucky-star/campaigns.php

Gaia was launched in 2013 to create the most precise three-dimensional map of more than one billion stars in the Milky Way. The mission has released two lots of data thus far: Gaia Data Release 1 in 2016 and Gaia Data Release 2 in 2018. More releases will follow in the coming years.

Gaia Data Release 1: http://sci.esa.int/gaia/58275-data-release-1/

Gaia Data Release 2: http://sci.esa.int/gaia/60243-data-release-2/

Juice is the first large-class mission in ESA’s Cosmic Vision 2015–2025 programme. It is planned for launch in 2022, and will complete a unique tour of Jupiter and its large ocean-bearing moons Europa, Ganymede and Callisto after it arrives in 2029.

Related links:

Gaia: http://sci.esa.int/gaia/ and http://www.esa.int/Our_Activities/Space_Science/Gaia

Juice: http://sci.esa.int/juice/

Images, Animations, Text, Credits: ESA/NASA/JPL/DLR/Gaia/DPAC; Bruno Morgado (Brazilian National Observatory/LIneA, Brazil) et al (2019).

Greetings, Orbiter.chArchive link

Europe prepares for Mars courier

ESA — European Space Agency patch.

25 July 2019

The first round-trip to the Red Planet will see a European orbiter bringing martian samples back to Earth. ESA is opening the door to industry to build the spacecraft that will deliver the precious rocks, dust and gas from Mars – the key to understanding whether life ever existed on our closest planetary neighbour.

Mars Sample Return – overview

This ‘take-away’ service is called the Earth Return Orbiter, and will be ESA’s major contribution to the Mars Sample Return campaign. The ESA Orbiter will carry NASA’s Capture and Containment and Return System, which will rely on the ESA-led spacecraft for transit to and from Mars.

Three launches from Earth and one from Mars – the first ever from another planet –, two rovers and an autonomous capture in Mars orbit are all part of an ambitious series of missions that ESA is embarking on together with NASA.

The campaign aims to bring at least 500 grams of samples back from the Jezero crater that once held a lake and contains an ancient preserved river delta. The rocks in the area preserve information about Mars’ diverse geology.

NASA’s Mars 2020 rover that is slated for launch in July 2020 will scientifically select the best samples to store in tubes and deposit them onto the martian surface for later retrieval.

Mars Sample Return overview infographic

ESA is also studying concepts for a small ‘fetch’ rover to scurry quickly across the martian surface to locate and recover the stored samples.

It would then carry them back to a football-sized canister that would be launched with a NASA Mars Ascent System – a small rocket.

The Earth Return Orbiter will capture the canister in orbit and transfer it safely to Earth, a return trip that will take about 13 months.

“We will have the responsibility of finding, capturing and transporting these precious martian treasures home for careful analysis in state-of-the-art labs on our planet,” explains Sanjay Vijendran, ESA’s Mars Sample Return campaign coordinator. “It’s an interplanetary treasure hunt!”

Bringing Mars back to Earth

The Earth Return Orbiter is set to get onto the launch pad by 2026 from Europe’s spaceport in Kourou, French Guiana. Through this call, ESA will be selecting a prime contractor for the spacecraft.

“The mission is becoming a reality, and we are proud to give European industry the chance to join the challenge,” says Orson Sutherland, study manager for the Earth Return Orbiter.

Mars sample return

The main challenges are the electric propulsion and power generation. “Not to forget finding and navigating the spacecraft to rendezvous with the football sized orbiting sample over 50 million km away from ground control,” adds Orson.

The spacecraft will use technological heritage from ESA’s most recently launched science mission, BepiColombo: both use electric propulsion and multi-stage detachable modules.

“Europe is ready to do its bit for the Mars Sample Return campaign, in close partnership with NASA, and is up to the challenge of putting the spacecraft onto the launch pad in 2026,” says Orson.

Related links:

European vision for space exploration: http://www.esa.int/Our_Activities/Human_and_Robotic_Exploration/A_new_European_vision_for_space_exploration

ExoMars: Europe’s new era of Mars exploration: http://www.esa.int/Our_Activities/Human_and_Robotic_Exploration/Exploration/ExoMars

Robotic exploration of Mars: http://exploration.esa.int/

Mars Sample Return: http://www.esa.int/Our_Activities/Human_and_Robotic_Exploration/Exploration/Mars_sample_return

Images, Video, Text, Credits: ESA/K. Oldenburg/ATG Medialab/NASA.

Best regards, Orbiter.chArchive link

Patrouille de France: «The plane is off the track»

Patrouille de France patch.

July 25, 2019

Just landed at the airport of Perpignan, the plane went off the track and ended not far from a road. The pilot who ejected was slightly injured.

Image above: The Alphajet of the Patrouille de France hit a wall, along the road. Image Credits: Twitter/France 3.

The Alphajets are now equipped with ejectable seats «zero-zero» (for zero altitude, zero speed), the pilot could eject, as provided by the procedure in case of loss of control. He was slightly injured.

The Patrouille de France. Image Credit: Patrouille de France

The plane caused a start of vegetation fire that could be controlled. The Patrouille de France was expected in the afternoon at Saint-Cyprien for an air demonstration.

Editor note:

This article is the 8000th published (since October 2010) on this blog by Roland Berga aka Orbiter.ch.

Related link:

Patrouille de France: http://www.patrouilledefrance.fr/

Images (mentioned), Text, Credits: Le Matin/wikipedia.org/Orbiter.ch Aerospace/Roland Berga.

Greetings, Orbiter.chArchive link

2019 July 25 Cygnus Skyscape Image Credit & Copyright: …

2019 July 25

Cygnus Skyscape
Image Credit & Copyright: Alistair Symon

Explanation: In brush strokes of interstellar dust and glowing hydrogen gas, this beautiful skyscape is painted across the plane of our Milky Way Galaxy near the northern end of the Great Rift and the constellation Cygnus the Swan. Composed with three different telescopes and about 90 hours of image data the widefield mosaic spans an impressive 24 degrees across the sky. Alpha star of Cygnus, bright, hot, supergiant Deneb lies near top center. Crowded with stars and luminous gas clouds Cygnus is also home to the dark, obscuring Northern Coal Sack Nebula, extending from Deneb toward the center of the view. The reddish glow of star forming regions NGC 7000, the North America Nebula and IC 5070, the Pelican Nebula, are just left of Deneb. The Veil Nebula is a standout below and left of center. A supernova remnant, the Veil is some 1,400 light years away, but many other nebulae and star clusters are identifiable throughout the cosmic scene. Of course, Deneb itself is also known to northern hemisphere skygazers for its place in two asterisms – marking the top of the Northern Cross and a vertex of the Summer Triangle.

∞ Source: apod.nasa.gov/apod/ap190725.html

Science Coming Soon to a Space Station Near You

Dozens of science experiments will soon make their red carpet debuts on the International Space Station. They will arrive courtesy of a Dragon cargo spacecraft launched from Cape Canaveral Air Force Station in Florida. The starring players include investigations into 3D printing organ tissue, breaking up rocks and building bones.

Meet some of the experiments blasting off that could lead to the development of new technologies as well as improve life on Earth.

Grab yourself an (organ) tissue

Scientists and medical professionals have long dreamed of the day 3D printers can be used to create useable human organs. But pesky gravity seems to always get in the way.


Enter microgravity. The new BioFabrication Facility (BFF) will provide a platform to attempt the creation of this organ tissue on the space station, a potential first step towards creating entire human organs in space.

Put down your pickaxe and pick up some microbes

Extracting minerals from rocks doesn’t always require brute force. Microbes can be deployed for the same purpose in a process called bio-mining. While common on Earth, the method still needs to be explored in space to see if it can eventually help explorers on the Moon and Mars. The BioRock investigation will examine the interactions between microbes and rocks and see if microgravity could limit the use of bio-mining by restricting bacterial growth.


Keep rolling along 

Goodyear Tire will investigate if microgravity can help improve the silica design process, silica rubber formation and tire manufacturing. This investigation could lead to improvements like better tire performance and increased fuel efficiency, putting a bit of cash back in your pocket.


When space gets on our nerves

Meet microglia: a type of immune defense cell found in the central nervous system. Better understanding nerve cells and their behavior in microgravity is crucial to protecting astronaut health. 

The Space Tango-Induced Pluripotent Stem Cells experiment will convert induced pluripotent stem cells (iPSCs) derived from patients with Parkinson’s and Multiple Sclerosis into different types of brain cells. Researchers will examine two things:

  1. How microglial cells grow and move

  2. Changes in gene expression in microgravity


Studying this process in microgravity could reveal mechanisms not previously understood and could lead to improved prevention and treatments for the diseases.

Space moss!

Moss, the tiny plants you see covering rocks and trees in the woods, change how they behave once the gravity in their environment changes. Space Moss compares the mosses grown aboard the space station with your typical run-of-the-mill Earth-bound moss.


This investigation will let researchers see how moss behavior in space could allow it to serve as a source of food and oxygen on future Moon or Mars bases.

A smooth connection 

Docking with the space station requires physical points for connections, and International Docking Adapters (IDAs) are providing a more sophisticated way of doing so.


IDA 3 will be attached to the Harmony mode, home to two existing IDAs. This adapter can accommodate commercial crew vehicle dockings, such as the first spacecraft to launch from U.S. soil since the space shuttle.

Building a better bone 

The Cell Science-02 investigation will improve our understanding of tissue regeneration and allow us to develop better countermeasures to fight loss of bone density by astronauts.


By examining the effects of microgravity on healing agents, this investigation may be able to assist people on Earth being treated for serious wounds or osteoporosis.

Want to learn about more investigations heading to the space station (or even ones currently under way)? Make sure to follow @ISS_Research on Twitter and Space Station Research and Technology News on Facebook

If you want to see the International Space Station with your own eyes, check out Spot the Station to see it pass over your town.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com.

How black holes shape galaxies

Outflows from a black hole

Credit: ESA/ATG medialab

Data from ESA’s XMM-Newton X-ray observatory has revealed how supermassive black holes shape their host galaxies with powerful winds that sweep away interstellar matter.

In a new study, scientists analysed eight years of XMM-Newton observations of the black hole at the core of an active galaxy known as PG 1114+445, showing how ultrafast winds – outflows of gas emitted from the accretion disk very close to the black hole – interact with the interstellar matter in central parts of the galaxy. These outflows have been spotted before but the new study clearly identifies, for the first time, three phases of their interaction with the host galaxy.

«These winds might explain some surprising correlations that scientists have known about for years but couldn’t explain,» said lead author Roberto Serafinelli of the National Institute of Astrophysics in Milan, Italy, who conducted most of the work as part of his PhD at University of Rome Tor Vergata.

«For example, we see a correlation between the masses of supermassive black holes and the velocity dispersion of stars in the inner parts of their host galaxies. But there is no way this could be due to the gravitational effect of the black hole. Our study for the first time shows how these black hole winds impact the galaxy on a larger scale, possibly providing the missing link.»

Astronomers have previously detected two types of outflows in the X-ray spectra emitted by the active galactic nuclei, the dense central regions of galaxies known to contain supermassive black holes. The so-called ultra-fast outflows (UFOs), made of highly ionised gas, travel at speeds up to 40 per cent the speed of light and are observable in the vicinity of the central black hole.

Slower outflows, referred to as warm absorbers, travel at much lower speeds of hundreds of km/s and have similar physical characteristics – such as particle density and ionisation – to the surrounding interstellar matter. These slower outflows are more likely to be detected at greater distances from the galaxy centres.

In the new study, the scientists describe a third type of outflow that combines characteristics of the previous two: the speed of a UFO and the physical properties of a warm absorber.

«We believe that this is the point when the UFO touches the interstellar matter and sweeps it away like a snowplough,» said Serafinelli. «We call this an ‘entrained ultra-fast outflow’ because the UFO at this stage is penetrating the interstellar matter. It’s similar to wind pushing boats in the sea.»

This entraining happens at a distance of tens to hundreds light years away from the black hole. The UFO gradually pushes the interstellar matter away from the central parts of the galaxy, clearing it from gas and slowing down the accretion of matter around the supermassive black hole.

While models have predicted this type of interaction before, the current study is the first to present actual observations of the three phases.

«In the XMM-Newton data, we can see material at larger distances from the centre of the galaxy that hasn’t been disturbed yet by the inner UFO,» said co-author Francesco Tombesi of University of Rome Tor Vergata and NASA’s Goddard Space Flight Center. «We can also see clouds closer to the black hole, near the core of the galaxy, where the UFO has started interacting with the interstellar matter.»

This first interaction happens many years after the UFO has left the black hole. But the energy of the UFO enables the relatively small black hole to impact material far beyond the reach of its gravitational force.

According to the scientists, supermassive black holes transfer their energy into the surrounding environment through these outflows and gradually clear the central regions of the galaxy from gas, which could then halt star formation. In fact, galaxies today produce stars far less frequently than they used to in the early stages of their evolution.

«This is the sixth time these outflows have been detected,» said Serafinelli. «It’s all very new science. These phases of the outflow have previously been observed separately but the connection between them wasn’t clear up until now.»

XMM-Newton’s unprecedented energy resolution was key to differentiating between the three types of features corresponding to the three types of outflows. In the future, with new and more powerful observatories such as ESA’s Advanced Telescope for High ENergy Astrophysics, Athena, astronomers will be able to observe hundreds of thousands of supermassive black holes, detecting such outflows more easily. Athena, which will be more than 100 times more sensitive than XMM-Newton, is scheduled for launch in the early 2030s.

«Finding one source is great but knowing that this phenomenon is common in the Universe would be a real breakthrough,» said Norbert Schartel, XMM-Newton project scientist at ESA. «Even with XMM-Newton, we might be able to find more such sources in the next decade.»

More data in the future will help unravel the complex interactions between the supermassive black holes and their host galaxies in detail and explain the decrease in star formation that astronomers observe to have taken place over billions of years.

Notes for Editors

«Multiphase quasar-driven outflows in PG 1114+445 – I. Entrained ultra-fast outflows» by R. Serafinelli et al. is published in Astronomy & Astrophysics.

For more information, please contact:

Roberto Serafinelli
National Institute of Astrophysics
Osservatorio Astronomico di Brera, Milan, Italy
and University of Rome Tor Vergata, Italy
Email: roberto.serafinelli@inaf.it

Francesco Tombesi
University of Rome Tor Vergata, Italy
NASA’s Goddard Space Flight Center
Greenbelt, MD, USA
INAF — Astronomical Observatory of Rome, Italy
University of Maryland, College Park, USA
Email: francesco.tombesi@roma2.infn.it

Norbert Schartel
XMM-Newton Project Scientist
European Space Agency
Email: norbert.schartel@esa.int

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Dragon Targets Launch Today as Science Ramps Up Aboard Busy Station

ISS — Expedition 60 Mission patch.

July 24, 2019

Forecasters predict a 30% chance of favorable weather today for the liftoff of a U.S. cargo craft at 6:24 p.m. EDT from Florida. Mission managers are getting ready to launch the SpaceX Dragon loaded with new science experiments and the International Docking Adapter-3.

Dragon is planned to arrive at the orbiting lab Friday at 10 a.m. NASA Flight Engineers Nick Hague and Christina Koch will be on duty in the cupola to command the Canadarm2 robotic arm to capture Dragon.

Meanwhile on the International Space Station, the expanded Expedition 60 crew stepped up their science activities with virtual reality filming, free-flying robotics tests and RNA sequencing.

Image above: Expedition 60 Flight Engineer Christina Koch of NASA monitors a mobility test of the free-flying Astrobee robotic assistant. Image Credit: NASA.

New crewmember Drew Morgan of NASA filmed himself today with a 360-degree camera inside the Harmony module. Morgan talked into the camera, as have previous station residents, describing his experience adapting to life in microgravity for the first time. Luca Parmitano of the European Space Agency set up the camera this morning to record the virtual reality experience for audiences on Earth.

Morgan and Parmitano along with Roscosmos cosmonaut Alexander Skvortsov are still getting up to speed with life on the orbiting laboratory. The crewmates have been in space less than a week and are familiarizing themselves with safety procedures and the station’s galley, crew quarters, medicine cabinet and toilet.

NASA Flight Engineer Christina Koch split her time today between robotics and RNA sequencing. She set up the Astrobee robotic helper in the morning testing and calibrating its free-flying motion. In the afternoon, Koch inserted RNA samples from a science freezer into the Biomolecule Sequencer to study how the space environment affects biology.

Image above: SpaceX’s Falcon 9 rocket stands ready for lift off at Cape Canaveral Air Force Station’s Space Launch Complex 40 in Florida for the company’s 18th Commercial Resupply Services (CRS-18) mission to the International Space Station. Launch is scheduled for 6:24 p.m. EDT. Photo Credit: NASA.

Flight Engineer Nick Hague inspected the U.S. Destiny laboratory’s large viewing window today. He photographed and checked the window used for Earth observation studies for cracks, scratches and contamination.

Cosmonauts Alexey Ovchinin and Alexander Skvortsov focused on configuring the recently arrived Soyuz MS-13 crew ship docked to the Zvezda service module. The veteran station residents also tested an automated rendezvous system ahead of the launch of a new Progress 73 cargo craft planned for July 31.

The High Definition Earth-Viewing (HDEV) experiment on the International Space Station has experienced a loss of data, and ground computers are no longer receiving communications from the payload. A team of engineers is reviewing the available health and status information from HDEV to identify what may have occurred.  Additional updates will be published as they become available.

Related links:

Expedition 60: https://www.nasa.gov/mission_pages/station/expeditions/expedition60/index.html

SpaceX: https://www.nasa.gov/spacex

Canadarm2: https://www.nasa.gov/mission_pages/station/structure/elements/mobile-servicing-system.html

Docking Adapter-3 (IDA-3): https://www.nasa.gov/feature/meet-the-international-docking-adapter

Harmony module: https://www.nasa.gov/mission_pages/station/structure/elements/harmony

Zvezda service module: https://www.nasa.gov/mission_pages/station/structure/elements/zvezda-service-module.html

360-degree camera: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7877

Biomolecule Sequencer: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1917

U.S. Destiny laboratory: https://www.nasa.gov/mission_pages/station/structure/elements/us-destiny-laboratory

Soyuz MS-13 crew ship: https://go.nasa.gov/2Z1JHG9

European Space Agency (ESA): https://www.esa.int/ESA

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

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

Best regards, Orbiter.chArchive link

Inside Dark, Polar Moon Craters, Water Not as Invincible as Expected, Scientists Argue

NASA — Lunar Reconnaissance Orbiter (LRO) patch.

July 24, 2019

NASA’s Lunar Reconnaissance Orbiter (LRO). Image Credit: NASA

The Moon’s south pole region is home to some of the most extreme environments in the solar system: it’s unimaginably cold, massively cratered, and has areas that are either constantly bathed in sunlight or in darkness. This is precisely why NASA wants to send astronauts there in 2024 as part of its Artemis program.

The most enticing feature of this southernmost region is the craters, some of which never see the light of day reach their floors. The reason for this is the low angle of sunlight striking the surface at the poles. To a person standing at the lunar south pole, the Sun would appear on the horizon, illuminating the surface sideways, and, thus, skimming primarily the rims of some craters while leaving their deep interiors in shadow.

Animation above: Streams of meteoroids striking the Moon’s surface. AnimationCredits: NASA’s Goddard Space Flight Center.

As a result of the permanent darkness, NASA’s Lunar Reconnaissance Orbiter (LRO) has measured the coldest temperatures in the solar system inside these craters, which have become known as perfect environments for preserving material like water for eons. Or so we thought.

It turns out that despite temperature that dips to -388 degrees Fahrenheit (-233 Celsius) and can presumably keep frost locked in soil virtually forever, water is slowly escaping the topmost, super thin layer (thinner than the width of a red blood cell) of the Moon’s surface. NASA scientists reported this finding recently in paper in the journal Geophysical Research Letters.

“People think of some areas in these polar craters as trapping water and that’s it,” said William M. Farrell, a plasma physicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, who led the lunar frost research. “But there are solar wind particles and meteoroids hitting the surface, and they can drive reactions that typically occur at warmer surface temperatures. That’s something that’s not been emphasized.”

Image above: A high-resolution free-air gravity map based on data returned from NASA’s Gravity Recovery and Interior Laboratory mission, overlaid on terrain based on NASA’s Lunar Reconnaissance Orbiter altimeter and camera data. The view is south-up, with the south pole near the horizon in the upper left. The terminator crosses the eastern rim of the Schrödinger basin. Gravity is painted onto the areas that are in or near the night side. Red corresponds to mass excesses and blue to mass deficits. Image Credits: NASA’s Scientific Visualization Studio.

Unlike Earth, with its plush atmosphere, the Moon has no atmosphere to protect its surface. So when the Sun sprays charged particles known as the solar wind into the solar system, some of them bombard the Moon’s surface and kick up water molecules that bounce around to new locations.

Likewise, wayward meteoroids constantly smash into the surface and uproot soil mingled with frozen bits of water. Meteoroids can hurtle these soil particles — which are many times smaller than the width of a human hair — as far as 19 miles (30 kilometers) away from the impact site, depending on the size of the meteoroid. The particles can travel so far because the Moon has low gravity and no air to slow things down: “So every time you have one of these impacts, a very thin layer of ice grains is spread across the surface, exposed to the heat of the Sun and to the space environment, and eventually sublimated or lost to other environmental processes,” said Dana Hurley, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland.

While it’s important to consider that even in the shadowed craters water is slowly seeping out, it’s possible that water is being added, too, the paper authors note. Icy comets that crash into the Moon, plus the solar wind, could be replenishing it as part of a global water cycle; that’s something scientists are trying to figure out. Additionally, it’s not clear how much water there is. Is it sitting only in the top layer of the Moon’s surface or does it extend deep into the Moon’s crust, scientists wonder?

Either way, the topmost layer of polar crater floors is getting reworked over thousands of years, according to calculations by Farrell, Hurley, and their team. Therefore, the faint patches of frost that scientists have detected at the poles using instruments such as LRO’s Lyman Alpha Mapping Project (LAMP) instrument could be just 2,000 years old, instead of millions or billions of years old as some might expect, Farrell’s team estimated. “We can’t think of these craters as icy dead spots,” he noted.

To confirm his team’s calculations, Farrell said, a future instrument capable of detecting water vapor should find, above the Moon’s surface, one to 10 water molecules per cubic centimeter that have been liberated by impacts.

The Good News for Future Lunar Exploration

For forthcoming science and exploration, the scattering of water particles could be great news. It means astronauts may need not to subject themselves and their instruments to the harsh environment of shadowed crater floors in order to find water-rich soil — they could just find it in sunny regions nearby.

Image above: A permanently shadowed lunar crater. Image Credits: NASA’s Goddard Space Flight Center.

“This research is telling us that meteoroids are doing some of the work for us and transporting material from the coldest places to some of the boundary regions where astronauts can access it with a solar-powered rover,” Hurley said. “It’s also telling us that what we need to do is get on the surface of one of these regions and get some firsthand data about what’s happening.”

Getting to the lunar surface would make it much easier to assess how much water is on the Moon. Because identifying water from afar, particularly in permanently shadowed craters, is tricky business. The primary way that scientists find water is through remote sensing instruments that can identify what chemical elements things are made of based on the light they reflect or absorb. “But for that, you need a light source,” Hurley said. “And by definition, these permanently shadowed regions don’t have a strong one.”

Understanding the Water Environment on the Moon

Until NASA astronauts get back to the Moon to dig up some soil, or the agency sends new instruments near the surface that can sniff out floating water molecules, the research team’s theory about the influence of meteoroids on the environment inside shadowed craters could help chip away at some of the mysteries surrounding the Moon’s water. It already has helped scientists understand if the uppermost surface water is new or ancient, or how it may migrate around the Moon. Another thing meteoroid impacts to the crater floors could help explain is why scientists are finding patches of wispy frost diluted in regolith, or Moon soil, rather than blocks of pure water ice.

Animation above: This animation shows evidence of high concentrations of hydrogen at the south pole of the Moon. In 1998 NASA’s Lunar Prospector mission identified hydrogen on the Moon, which was early evidence of potential ice deposits. As you can see in this video, Prospector data showed significantly more hydrogen (shown in blue) at the Moon’s south pole. Animation Credits: NASA’s Goddard Space Flight Center Scientific Visualization Studio.

Even though water questions abound, it’s important to remember, Farrell said, that it was only in the last decade that scientists found evidence that the Moon is not a dry, dead rock, as many had long assumed. The LRO, with its thousands of orbits and 1 petabyte of returned science data (equivalent to about 200,000, high-definition, feature-length films streamed online), has been instrumental. So has the Lunar Crater Observation and Sensing Satellite (LCROSS), which revealed frozen water after purposely crashing into Cabeus crater in 2009 and releasing a plume of preserved material from the crater floor that included water.

“We suspected there was water at the poles and learned for sure from LCROSS, but we now have evidence that there’s water at mid latitudes,” Farrell said. “We also have evidence that there’s water coming from micrometeoroid impacts, and we have measurements of frost. But the question is, how are all these water sources related?”

That’s a question Farrell and his colleagues are closer to answering than ever before.

Related links:

Lunar Reconnaissance Orbiter (LRO): http://www.nasa.gov/mission_pages/LRO/main/index.html

Geophysical Research Letters: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL083158

Earth’s Moon: http://www.nasa.gov/moon

Images (mentioned), Animations (mentioned), Text, Credits: NASA/Svetlana Shekhtman/Goddard Space Flight Center, by Lonnie Shekhtman.

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