среда, 13 ноября 2019 г.

Lunar IceCube Mission to Locate, Study Resources Needed for Sustained Presence on Moon













NASA Goddard Space Flight Center logo.

Nov. 13, 2019

As we venture forward to the Moon and establish a sustained lunar presence, finding and understanding water on the lunar surface becomes increasingly important. Lunar water is largely in the form of, but not necessarily limited to, water ice. Astronauts on the Moon could use this ice for various crew needs, potentially including rocket fuel. The Lunar IceCube mission, led by Morehead State University in Morehead, Kentucky, will study water distribution and interaction on the Moon. The mission will carry a NASA instrument called Broadband InfraRed Compact High-Resolution Exploration Spectrometer (BIRCHES) to investigate the distribution of water and other organic volatiles. NASA scientists will use this data to understand where the water is on the Moon, its origins and how we can use it.

“Lunar IceCube will help pave the way for human missions through significantly less expensive robotic missions and by addressing water dynamics on the Moon,” said Mark Lupisella, exploration research and development manager. “This is not only important for science, but it could also be important for reducing the cost of human missions over the long-term.”

The BIRCHES instrument will not only help map the distribution and dynamics of water on the Moon’s surface, but also in the exosphere — a very thin atmosphere-like volume surrounding the Moon. Scientists are interested in understanding the absorption and release of water from the Moon’s regolith, which is comparable to soil on Earth’s surface. By studying the absorption and release of water, scientists can start to map changes occurring on the Moon. Finding and understanding water on the lunar surface is vital to establishing a sustained presence on the Moon.


Image above: Illustration of Lunar IceCube in orbit. Image Credit: Morehead State University.

Lunar IceCube plans to have a seven-hour elliptical orbit around the Moon, where it will observe the lunar surface for an hour of that time. This limited observational time is due to BIRCHES’ view of the Moon. If the Sun peeks into the Lunar IceCube’s point of view while it is observing or travelling to the Moon, the BIRCHES instrument would be permanently damaged due to the intensity of the Sun’s energy on the infrared detector and other sensitive optical components within the instrument. To prevent this, the team developed a small garage-like door on the instrument that will open and close to protect the instrument.

Lunar IceCube is designed to provide several site observations at different latitudes for further understanding water cycles on the Moon. Additionally, the findings from Lunar IceCube will provide complimentary measurements to other CubeSats observing the Moon.

“Anything we learn about the Moon is valuable,” said Cliff Brambora, BIRCHES lead engineer. “The Moon is a kind of proving ground for technology and exploration, and the knowledge we gain there will help us with the potential for establishing a sustained presence on other planets, such as Mars.”

In addition to the miniaturized technology for the BIRCHES instrument, Lunar IceCube will feature an ion propulsion thruster, a new technology for CubeSats. Due to the minuscule size of the spacecraft, the thruster operates electrically using small amounts of propellant to give a small push and drive the spacecraft along its path, similar to that of butterfly wings.

"Interplanetary exploration with CubeSats is possible through the use of innovative propulsion systems and creative trajectories,” said Benjamin Malphrus from Morehead State University. “The ion propulsion system is an enabling technology that will open the door to solar system exploration with small satellite platforms, ushering in a new era of space exploration."


Image above: Visualization of Lunar IceCube’s Ion Propulsion Thruster. Image Credit: Busek Company.

As a CubeSat, a miniaturized satellite typically weighing less than 397 pounds, Lunar IceCube, which weighs 31 pounds, provides the agency with an efficient and cost-effective way to study the Moon. CubeSats offer NASA, universities and other organizations with a platform for science investigations, technology demonstrations and advanced mission concepts. The BIRCHES payload is roughly the size of an eight-inch tissue box, and during the development of BIRCHES, the team had to drastically miniaturize legacy hardware from a previous NASA mission to approximately one-sixth of its original size.

Lunar IceCube is a collaborative effort between NASA’s Goddard Space Flight Center in Greenbelt, Maryland; NASA’s Jet Propulsion Laboratory in Pasadena, California; NASA’s Katherine Johnson Independent Verification and Validation Center in Fairmont, West Virginia; Morehead State University (MSU); and commercial partners, including the Busek space propulsion company.

The BIRCHES instrument is currently undergoing environmental testing at Goddard and is planned for delivery to MSU in August for integration into the spacecraft. The mission will launch as a secondary payload on the Space Launch System’s (SLS) Artemis -1.

Lunar IceCube is paving the way for NASA’s mission to the Moon. By distinguishing water on and around the lunar surface, scientists will be able to predict seasonal changes and determine possible in situ use for water on the Moon. This will be valuable information as NASA works to establish a sustained lunar presence by 2024.

Related links:

Artemis -1: https://www.nasa.gov/what-is-artemis

Lunar IceCube: https://www.nasa.gov/feature/goddard/lunar-icecube-to-take-on-big-mission-from-small-package

CubeSats: http://www.nasa.gov/cubesats/

Small Satellite Missions: http://www.nasa.gov/mission_pages/smallsats

Artemis: https://www.nasa.gov/artemis

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

Images (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center, by Katherine Schauer.

Greetings, Orbiter.ch

* This article was originally published here

With Mars methane mystery unsolved, Curiosity serves scientists a new one: Oxygen


For the first time in the history of space exploration, scientists have measured the seasonal changes in the gases that fill the air directly above the surface of Gale Crater on Mars. As a result, they noticed something baffling: oxygen, the gas many Earth creatures use to breathe, behaves in a way that so far scientists cannot explain through any known chemical processes.

With Mars methane mystery unsolved, Curiosity serves scientists a new one: Oxygen
A sunset at the Viking Lander 1 site, 1976 
[Credit: NASA/JPL]
Over the course of three Mars years (or nearly six Earth years) an instrument in the Sample Analysis at Mars (SAM) portable chemistry lab inside the belly of NASA's Curiosity rover inhaled the air of Gale Crater and analyzed its composition. The results SAM spit out confirmed the makeup of the Martian atmosphere at the surface: 95% by volume of carbon dioxide (CO2), 2.6% molecular nitrogen (N2), 1.9% argon (Ar), 0.16% molecular oxygen (O2), and 0.06% carbon monoxide (CO).

They also revealed how the molecules in the Martian air mix and circulate with the changes in air pressure throughout the year. These changes are caused when CO2 gas freezes over the poles in the winter, thereby lowering the air pressure across the planet following redistribution of air to maintain pressure equilibrium. When CO2 evaporates in the spring and summer and mixes across Mars, it raises the air pressure.


Within this environment, scientists found that nitrogen and argon follow a predictable seasonal pattern, waxing and waning in concentration in Gale Crater throughout the year relative to how much CO2 is in the air. They expected oxygen to do the same. But it didn't. Instead, the amount of the gas in the air rose throughout spring and summer by as much as 30%, and then dropped back to levels predicted by known chemistry in fall. This pattern repeated each spring, though the amount of oxygen added to the atmosphere varied, implying that something was producing it and then taking it away.

"The first time we saw that, it was just mind boggling," said Sushil Atreya, professor of climate and space sciences at the University of Michigan in Ann Arbor. Atreya is a co-author of a paper on this topic published in the Journal of Geophysical Research: Planets.

As soon as scientists discovered the oxygen enigma, Mars experts set to work trying to explain it. They first double- and triple-checked the accuracy of the SAM instrument they used to measure the gases: the Quadrupole Mass Spectrometer. The instrument was fine. They considered the possibility that CO2 or water (H2O) molecules could have released oxygen when they broke apart in the atmosphere, leading to the short-lived rise. But it would take five times more water above Mars to produce the extra oxygen, and CO2 breaks up too slowly to generate it over such a short time. What about the oxygen decrease? Could solar radiation have broken up oxygen molecules into two atoms that blew away into space? No, scientists concluded, since it would take at least 10 years for the oxygen to disappear through this process.

With Mars methane mystery unsolved, Curiosity serves scientists a new one: Oxygen
Credit: Melissa Trainer/Dan Gallagher/NASA Goddard
"We're struggling to explain this," said Melissa Trainer, a planetary scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland who led this research. "The fact that the oxygen behavior isn't perfectly repeatable every season makes us think that it's not an issue that has to do with atmospheric dynamics. It has to be some chemical source and sink that we can't yet account for."

To scientists who study Mars, the oxygen story is curiously similar to that of methane. Methane is constantly in the air inside Gale Crater in such small quantities (0.00000004% on average) that it's barely discernable even by the most sensitive instruments on Mars. Still, it's been measured by SAM's Tunable Laser Spectrometer. The instrument revealed that while methane rises and falls seasonally, it increases in abundance by about 60% in summer months for inexplicable reasons. (In fact, methane also spikes randomly and dramatically. Scientists are trying to figure out why.)


With the new oxygen findings in hand, Trainer's team is wondering if chemistry similar to what's driving methane's natural seasonal variations may also drive oxygen's. At least occasionally, the two gases appear to fluctuate in tandem.

"We're beginning to see this tantalizing correlation between methane and oxygen for a good part of the Mars year," Atreya said. "I think there's something to it. I just don't have the answers yet. Nobody does."

Oxygen and methane can be produced both biologically (from microbes, for instance) and abiotically (from chemistry related to water and rocks). Scientists are considering all options, although they don't have any convincing evidence of biological activity on Mars. Curiosity doesn't have instruments that can definitively say whether the source of the methane or oxygen on Mars is biological or geological. Scientists expect that non-biological explanations are more likely and are working diligently to fully understand them.

With Mars methane mystery unsolved, Curiosity serves scientists a new one: Oxygen
Credit: Melissa Trainer/Dan Gallagher/NASA Goddard
Trainer's team considered Martian soil as a source of the extra springtime oxygen. After all, it's known to be rich in the element, in the form of compounds such as hydrogen peroxide and perchlorates. One experiment on the Viking landers showed decades ago that heat and humidity could release oxygen from Martian soil. But that experiment took place in conditions quite different from the Martian spring environment, and it doesn't explain the oxygen drop, among other problems.


Other possible explanations also don't quite add up for now. For example, high-energy radiation of the soil could produce extra O2 in the air, but it would take a million years to accumulate enough oxygen in the soil to account for the boost measured in only one spring, the researchers report in their paper.

"We have not been able to come up with one process yet that produces the amount of oxygen we need, but we think it has to be something in the surface soil that changes seasonally because there aren't enough available oxygen atoms in the atmosphere to create the behavior we see," said Timothy McConnochie, assistant research scientist at the University of Maryland in College Park and another co-author of the paper.

The only previous spacecraft with instruments capable of measuring the composition of the Martian air near the ground were NASA's twin Viking landers, which arrived on the planet in 1976. The Viking experiments covered only a few Martian days, though, so they couldn't reveal seasonal patterns of the different gases. The new SAM measurements are the first to do so. The SAM team will continue to measure atmospheric gases so scientists can gather more detailed data throughout each season. In the meantime, Trainer and her team hope that other Mars experts will work to solve the oxygen mystery.

"This is the first time where we're seeing this interesting behavior over multiple years. We don't totally understand it," Trainer said. "For me, this is an open call to all the smart people out there who are interested in this: See what you can come up with."

Author: Lonnie Shekhtman | Source: NASA's Goddard Space Flight Center [November 12, 2019]



* This article was originally published here

Terracina: A cosmopolitan city near Rome


In a new excavation project undertaken by German and Italian researchers, LMU archaeologists Paul Scheding and Francesca Diosono have uncovered evidence suggesting that Terracina was the site of the first Hellenistic temple in the region.

Terracina: A cosmopolitan city near Rome
Excavations on Monte Sant`Angelo in Terracina
[Credit: Paul Scheding/LMU]
High above the ancient city of Tarracina (now Terracina) south of Rome, there was once a large-scale terraced sanctuary that included a small temple. The building afforded a wide prospect over the harbor on one side and the Via Appia, the city's most important link with Rome, on the other.

In the course of an excavation project which is planned to last for three years, Paul Scheding and Francesca Diosono from the Institute for Classical Archaeology at LMU Munich will focus their attention primarily on the small temple.


They have now been able to reconstruct its exact extent, which allowed them to confirm that the structure was built during the second century BC. This makes it the oldest Hellenistic structure of this type in Latium, and perhaps the very first terraced temple in the region.

"The temple underlines the significance of Tarracina at this time," says Scheding. The city was obviously in contact with the most important Hellenistic cities in the Mediterranean, even before the Roman conquest of Latium.


The temple itself and Monte Sant'Angelo, the hill on which it was erected was once reserved for religious ceremonies. The excavations have also confirmed that temple's facade was oriented, not towards the harbor, but towards the Via Appia and the city below.


"On important feast-days, processions left the city and climbed the hill to the temple," says Scheding, and merchants and travelers also visited the temple. The excavators have not yet identified the god to whom the temple was dedicated. The shrine is associated with an unusually large number of cisterns, but what the water was needed for remains unclear.

The excavations have also uncovered traces of a pre-Roman settlement that dates back to the 7th or perhaps even as far as the 9th century BC. Who lived here before the construction of the temple is also unknown as yet.

Literary sources dating to the 6th century BC attest to the presence of the Volsci in the area, but these people have not been definitively associated with any archaeological finds in the area. Further work over the next two years may help to clarify how the shrine on Monte Sant'Angelo developed prior to and following the conquest of the region by the Romans.

Source: Ludwig Maximilian University of Munich [November 11, 2019]



* This article was originally published here

Women in Exploration: From Human Computers to All-Woman Spacewalks

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Since the 19th century, women have been making strides in areas like coding, computing, programming and space travel, despite the challenges they have faced. Sally Ride joined NASA in 1983 and five years later she became the first female American astronaut. Ride’s accomplishments paved the way for the dozens of other women who became astronauts, and the hundreds of thousands more who pursued careers in science and technology. Just last week, we celebrated our very first #AllWomanSpacewalk with astronauts Christina Koch and Jessica Meir.

Here are just a couple of examples of pioneers who brought us to where we are today:

The Conquest of the Sound Barrier

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Pearl Young was hired in 1922 by the National Advisory Committee for Aeronautics (NACA), NASA’s predecessor organization, to work at its Langley site in support in instrumentation, as one of the first women hired by the new agency. Women were also involved with the NACA at the Muroc site in California (now Armstrong Flight Research Center) to support flight research on advanced, high-speed aircraft. These women worked on the X-1 project, which became the first airplane to fly faster than the speed of sound. 

Young was the first woman hired as a technical employee and the second female physicist working for the federal government.

The Human Computers of Langley

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The NACA hired five women in 1935 to form its first “computer pool”, because they were hardworking, “meticulous” and inexpensive. After the United States entered World War II, the NACA began actively recruiting similar types to meet the workload. These women did all the mathematical calculations – by hand – that desktop and mainframe computers do today.

Computers played a role in major projects ranging from World War II aircraft testing to transonic and supersonic flight research and the early space program. Women working as computers at Langley found that the job offered both challenges and opportunities. With limited options for promotion, computers had to prove that women could successfully do the work and then seek out their own opportunities for advancement.

Revolutionizing X-ray Astronomy

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Marjorie Townsend was blazing trails from a very young age. She started college at age 15 and became the first woman to earn an engineering degree from the George Washington University when she graduated in 1951. At NASA, she became the first female spacecraft project manager, overseeing the development and 1970 launch of the UHURU satellite. The first satellite dedicated to x-ray astronomy, UHURU detected, surveyed and mapped celestial X-ray sources and gamma-ray emissions.

Women of Apollo

NASA’s mission to land a human on the Moon for the very first time took hundreds of thousands workers. These are some of the stories of the women who made our recent #Apollo50th anniversary possible:

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Margaret Hamilton led a NASA team of software engineers at the Massachusetts Institute of Technology and helped develop the flight software for NASA’s Apollo missions. She also coined the term “software engineering.” Her team’s groundbreaking work was perfect; there were no software glitches or bugs during the crewed Apollo missions. 


JoAnn Morgan was the only woman working in Mission Control when the Apollo 11 mission launched. She later accomplished many NASA “firsts” for women:  NASA winner of a Sloan Fellowship, division chief, senior executive at the Kennedy Space Center and director of Safety and Mission Assurance at the agency.


Judy Sullivan, was the first female engineer in the agency’s Spacecraft Operations organization, was the lead engineer for health and safety for Apollo 11, and the only woman helping Neil Armstrong suit up for flight.

Hidden Figures

Author Margot Lee Shetterly’s book – and subsequent movie – Hidden Figures, highlighted African-American women who provided instrumental support to the Apollo program, all behind the scenes.

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• An alumna of the Langley computing pool, Mary Jackson was hired as the agency’s first African-American female engineer in 1958. She specialized in boundary layer effects on aerospace vehicles at supersonic speeds. 


• An extraordinarily gifted student, Katherine Johnson skipped several grades and attended high school at age 13 on the campus of a historically black college. Johnson calculated trajectories, launch windows and emergency backup return paths for many flights, including Apollo 11.


Christine Darden served as a “computress” for eight years until she approached her supervisor to ask why men, with the same educational background as her (a master of science in applied mathematics), were being hired as engineers. Impressed by her skills, her supervisor transferred her to the engineering section, where she was one of few female aerospace engineers at NASA Langley during that time.

Lovelace’s Woman in Space Program

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Geraldyn “Jerrie” Cobb was the among dozens of women recruited in 1960 by Dr. William Randolph “Randy” Lovelace II to undergo the same physical testing regimen used to help select NASA’s first astronauts as part of his privately funded Woman in Space Program.

Ultimately, thirteen women passed the same physical examinations that the Lovelace Foundation had developed for NASA’s astronaut selection process. They were: Jerrie Cobb, Myrtle “K” Cagle, Jan Dietrich, Marion Dietrich, Wally Funk, Jean Hixson, Irene Leverton, Sarah Gorelick, Jane B. Hart, Rhea Hurrle, Jerri Sloan, Gene Nora Stumbough, and Bernice Trimble Steadman. Though they were never officially affiliated with NASA, the media gave these women the unofficial nicknames “Fellow Lady Astronaut Trainees” and the “Mercury Thirteen.”

The First Woman on the Moon

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The early space program inspired a generation of scientists and engineers. Now, as we embark on our Artemis program to return humanity to the lunar surface by 2024, we have the opportunity to inspire a whole new generation. The prospect of sending the first woman to the Moon is an opportunity to influence the next age of women explorers and achievers.

This material was adapted from a paper written by Shanessa Jackson (Stellar Solutions, Inc.), Dr. Patricia Knezek (NASA), Mrs. Denise Silimon-Hill (Stellar Solutions), and Ms. Alexandra Cross (Stellar Solutions) and submitted to the 2019 International Astronautical Congress (IAC). For more information about IAC and how you can get involved, click here.

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

Antarctica likely to drive rapid sea-level rise under climate change


Scientists from The Australian National University (ANU) have shown that ice melt from Antarctica drives rapid and high sea-level rise, offering a forewarning of what to expect under human-driven climate change.

Antarctica likely to drive rapid sea-level rise under climate change
Melting ice on the coast of Adelie Land in East Antarctica
[Credit: Pauline Askin/Reuters]
The researchers examined historical and new data from the ‘last interglacial’, which took place 125,000 to 118,000 years ago and saw sea levels rise up to 10 metres above current levels.

Interglacials are periods of warmer global temperatures that can last thousands of years.

The study, published in Nature Communications, shows that sea levels rose up to three metres per century, largely driven by ice loss in the Antarctic ice sheet.


Lead author, Professor Eelco Rohling, said that the last interglacial sea-rise was due to natural climate instabilities.

“These were smaller and slower than the human-caused climate disturbance of today,” he said.

“Our study shows clearly that Antarctica, long thought a sleeping giant when it comes to sea-level rises, is in fact the key player.

“And it appears that it can change by large amounts on timescales that are highly relevant to society and in ways that would have profound effects on human infrastructure.”

The study shows for the first time by how much ice loss in the last interglacial first took place in Antarctica, followed by Greenland.


Early Antarctic ice loss was caused by Southern Ocean warming at the onset of the interglacial. Next, the meltwater from Antarctica caused changes in global ocean circulation that resulted in northern polar warming and associated Greenland ice loss.

Co-lead author, Dr Fiona Hibbert, said that in today's greenhouse-gas-driven climate change, rapid atmospheric and oceanic warming happens in both polar regions at the same time.

“This drives simultaneous ice-loss in Antarctica and Greenland,” Dr Hibbert said.

“But, what’s vital to remember is that today’s climatic disturbance is greater and develops faster than that of the last interglacial.

“As a result, rates of sea-level rise may develop over the next several centuries that are even higher than those found for the interglacial we have studied.”

Source: Australian National University [November 06, 2019]



* This article was originally published here

2019 November 13 Mercury in Silhouette Image Credit &...



2019 November 13

Mercury in Silhouette
Image Credit & Copyright: Martin Wise

Explanation: The small, dark, round spot in this solar close up is planet Mercury. In the high resolution telescopic image, a colorized stack of 61 sharp video frames, a turbulent array of photospheric convection cells tile the bright solar surface. Mercury’s more regular silhouette still stands out though. Of course, only inner planets Mercury and Venus can transit the Sun to appear in silhouette when viewed from planet Earth. For this November 11, 2019 transit of Mercury, the innermost planet’s silhouette was a mere 1/200th the solar diameter. So even under clear daytime skies it was difficult to see without the aid of a safe solar telescope. Following its transit in 2016, this was Mercury’s 4th of 14 transits across the solar disk in the 21st century. The next transit of Mercury will be on November 13, 2032.

∞ Source: apod.nasa.gov/apod/ap191113.html

Far, Far Away in the Sky: New Horizons Kuiper Belt Flyby Object Officially Named 'Arrokoth'













NASA - New Horizons Mission patch.

Nov. 12, 2019

In a fitting tribute to the farthest flyby ever conducted by spacecraft, the Kuiper Belt object 2014 MU69 has been officially named Arrokoth, a Native American term meaning “sky” in the Powhatan/Algonquian language.

With consent from Powhatan Tribal elders and representatives, NASA’s New Horizons team – whose spacecraft performed the record-breaking reconnaissance of Arrokoth four billion miles from Earth – proposed the name to the International Astronomical Union and Minor Planets Center, the international authority for naming Kuiper Belt objects. The name was announced at a ceremony today at NASA Headquarters in Washington, DC.

“The name ‘Arrokoth’ reflects the inspiration of looking to the skies and wondering about the stars and worlds beyond our own,” said Alan Stern, New Horizons principal investigator from Southwest Research Institute, Boulder, Colorado. “That desire to learn is at the heart of the New Horizons mission, and we’re honored to join with the Powhatan community and people of Maryland in this celebration of discovery.”


Image above: Composite image of primordial contact binary Kuiper Belt Object 2014 MU69 from New Horizons Spacecraft Data. Image Credits: NASA/JHUAPL.

New Horizons launched in January 2006; it then zipped past Jupiter for a gravity boost and scientific studies in February 2007 and conducted an historic first flight through the Pluto system on July 14, 2015. The spacecraft continued its unparalleled voyage on New Year’s 2019 with the exploration of Arrokoth – which the team had nicknamed “Ultima Thule” ­-- a billion miles beyond Pluto, and the farthest flyby ever conducted.

Arrokoth is one of the thousands of known small icy worlds in the Kuiper Belt, the vast “third zone” of the solar system beyond the inner terrestrial planets and the outer gas giant planets. It was discovered in 2014 by a New Horizons team – which included Marc Buie, of the Southwest Research Institute – using the powerful Hubble Space Telescope.

“Data from the newly-named Arrokoth, has given us clues about the formation of planets and our cosmic origins,” said Buie. “We believe this ancient body, composed of two distinct lobes that merged into one entity, may harbor answers that contribute to our understanding of the origin of life on Earth.”

In accordance with IAU naming conventions, the discovery team earned the privilege of selecting a permanent name for the celestial body. The team used this convention to associate the culture of the native peoples who lived in the region where the object was discovered; in this case, both the Hubble Space Telescope (at the Space Telescope Science Institute) and the New Horizons mission (at the Johns Hopkins Applied Physics Laboratory) are operated out of Maryland — a tie to the significance of the Chesapeake Bay region to the Powhatan people.

“We graciously accept this gift from the Powhatan people,” said Lori Glaze, director of NASA’s Planetary Science Division. “Bestowing the name Arrokoth signifies the strength and endurance of the indigenous Algonquian people of the Chesapeake region. Their heritage continues to be a guiding light for all who search for meaning and understanding of the origins of the universe and the celestial connection of humanity.”

New Horizons Path of Exploration. Image Credits: NASA/MSFC

The Pamunkey Reservation in King William County, Virginia, is the oldest American Indian reservation in the U.S. -- formed by a treaty with England in the 1600s and finally receiving federal recognition in July 2015. The Pamunkey tribe and its village were significant in the original Powhatan Confederacy; today, Pamunkey tribal members work collaboratively with other Powhatan tribes in Virginia and also have descendants who are members of the Powhatan-Renape Nation in New Jersey. Many direct descendants still live on the Pamunkey reservation, while others have moved to Northern Virginia, Maryland, D.C., New York and New Jersey.

The Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, designed, built and operates the New Horizons spacecraft, and manages the mission for NASA's Science Mission Directorate. NASA’s Marshall Space Flight Center (MSFC) Planetary Management Office, in Huntsville, Alabama, provides the NASA oversight for the New Horizons. The Southwest Research Institute, based in San Antonio, directs the mission via Principal Investigator Stern, and leads the science team, payload operations and encounter science planning. New Horizons is part of the New Frontiers Program managed by NASA's MSFC.

For more information about New Horizons, visit: https://www.nasa.gov/mission_pages/newhorizons/main/index.html

Images (mentioned), Text, Credits: NASA/Tricia Talbert/Grey Hautaluoma/Alana Johnson/Johns Hopkins University Applied Physics Laboratory/Michael Buckley.

Greetings, Orbiter.ch

* This article was originally published here

The alchemy of merging neutron stars


For the first time, astronomers have identified a chemical element that was freshly formed by the merging of two neutron stars. The underlying mechanism, called the r-process—also known as rapid neutron capture—is considered to be the origin of large quantities of elements heavier than iron.

The alchemy of merging neutron stars
Credit: MPA
This discovery sheds new light on the mystery of the environments in which this r-process takes place. The team of astronomers, also including scientists of FAIR and GSI, has now unequivocally demonstrated that the fusion of two neutron stars creates the conditions for this process and acts as a reactor in which new elements are bred.


The origin of heavy elements such as gold, lead and uranium has not yet been fully clarified. The lightest elements—hydrogen and helium—were already formed in significant quantities with the Big Bang. Nuclear fusion in the cores of stars is also a well-established source of atoms in the mass range from helium to iron.

For the production of heavier atoms, scientists suspect a process that attaches free neutrons to already existing building blocks. The fast variant of this mechanism is the so-called r-process (r stands for rapid) or fast neutron capture. At present, research is being carried out to determine which objects might be sites where this reaction takes place. Possible candidates so far are a rare type of supernova explosions and the merging of dense stellar remnants like binary neutron stars.

Large amounts of strontium form within less than a second

An international group of astronomers with substantial participation of Camilla Juul Hansen from the Max Planck Institute for Astronomy (MPIA) in Heidelberg has now discovered the signature of the element strontium, which was formed by the r-process during an explosive fusion of two neutron stars. With on average 88 nucleons, of which 38 are protons, it is heavier than iron.

Professor Almudena Arcones and Privatdozent Andreas Bauswein were also involved in the publication in the scientific journal Nature. In addition to their activities in the research department for theoretical physics at FAIR and GSI, they are also active at the Technical University of Darmstadt and at the University of Heidelberg, both partner universities of FAIR and GSI. They provided valuable estimates for the publication. The process and characteristics of the r-process are among the important research questions to be investigated at the future FAIR accelerator facility currently under construction in Darmstadt.


The explosive merger produced a raging expansion shell moving with 20% to 30% of the speed of light. It consists of newly formed matter, of which strontium alone amounts to about five Earth masses (1 Earth mass = 6·1024 kg). Thus, for the first time, the researchers provide clear evidence that such a collision provides the conditions for the r-process in which heavy elements form. Besides, this is the first empirical confirmation that neutron stars consist of neutrons.

The r-process is truly rapid. Per second, more than 10²² neutrons flow through an area of one square centimetre. The beta decay transforms some of the accumulated neutrons into protons, emitting one electron and one antineutrino each. The special aspect about this mechanism is that the neutrons combine to form large compounds faster than the newly formed conglomerates break up again. In this way, even heavy elements can grow from individual neutrons within less than a second.

Merging neutron stars produce gravitational waves

Using the Very Large Telescope (VLT) of the European Southern Observatory (ESO), scientists obtained spectra following the spectacular discovery of the gravitational wave signal GW170817 in August 2017. In addition to a gamma-ray burst, the kilonova AT2017gfo, an afterglow in visible light due to radioactive processes, which faded within a few days after an initial sharp increase in brightness, occurred at the same location. The first analysis of the spectra in 2017 by another group of researchers did not yield a clear result about the composition of the reaction products.


Dr. Hansen and her colleagues based their re-evaluation on creating synthetic spectra and modeling the observed spectra, which were recorded over four days at intervals of one day each. The spectra indicate an object with an initial temperature of about 3700 K (approx. 3400 °C), which faded and cooled in the following days. The brightness deficits at wavelengths of 350 and 850 nm are conspicuous. These are like fingerprints of the element that absorbs light at these parts of the spectrum.

Taking into account the blue shift of these absorption lines caused by the Doppler effect the expansion following the merger event produces, the research group calculated spectra of a large number of atoms using three increasingly complex methods. Since these methods all yielded consistent results, the final conclusion is robust. It turned out that only strontium generated by the r-process is able to explain the positions and strength of the absorption features in the spectra.

Progress in the understanding of the nucleosynthesis of heavy elements

"The results of this work are an important step in deciphering the nucleosynthesis of heavy elements and their cosmic sources," Hansen concludes. "This was only possible by combining the new discipline of gravitational wave astronomy with precise spectroscopy of electromagnetic radiation. These new methods give hope for further ground-breaking insights into the nature of the r-process."

Source: Technische Universitat Darmstadt [November 07, 2019]



* This article was originally published here

NASA's Mars 2020 Will Hunt for Microscopic Fossils













NASA - Mars 2020 Rover logo.

Nov. 12, 2019

Scientists with NASA's Mars 2020 rover have discovered what may be one of the best places to look for signs of ancient life in Jezero Crater, where the rover will land on Feb. 18, 2021.

A paper published today in the journal Icarus identifies distinct deposits of minerals called carbonates along the inner rim of Jezero, the site of a lake more than 3.5 billion years ago. On Earth, carbonates help form structures that are hardy enough to survive in fossil form for billions of years, including seashells, coral and some stromatolites — rocks formed on this planet by ancient microbial life along ancient shorelines, where sunlight and water were plentiful.


Image above: Lighter colors represent higher elevation in this image of Jezero Crater on Mars, the landing site for NASA's Mars 2020 mission. The oval indicates the landing ellipse, where the rover will be touching down on Mars. Image Credits: NASA/JPL-Caltech/MSSS/JHU-APL/ESA.

The possibility of stromatolite-like structures existing on Mars is why the concentration of carbonates tracing Jezero's shoreline like a bathtub ring makes the area a prime scientific hunting ground.

Mars 2020 is NASA's next-generation mission with a focus on astrobiology, or the study of life throughout the universe. Equipped with a new suite of scientific instruments, it aims to build on the discoveries of NASA's Curiosity, which found that parts of Mars could have supported microbial life billions of years ago. Mars 2020 will search for actual signs of past microbial life, taking rock core samples that will be deposited in metal tubes on the Martian surface. Future missions could return these samples to Earth for deeper study.

In addition to preserving signs of ancient life, carbonates can teach us more about how Mars transitioned from having liquid water and a thicker atmosphere to being the freezing desert it is today. Carbonate minerals formed from interactions between carbon dioxide and water, recording subtle changes in these interactions over time. In that sense, they act as time capsules that scientists can study to learn when — and how — the Red Planet began drying out.

Measuring 28 miles (45 kilometers) wide, Jezero Crater was also once home to an ancient river delta. The "arms" of this delta can be seen reaching across the crater floor in images taken from space by satellite missions like NASA's Mars Reconnaissance Orbiter. The orbiter's Compact Reconnaissance Imaging Spectrometer for Mars instrument, or CRISM, helped produce colorful mineral maps of the "bathtub ring" detailed in the new paper.

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Hubble captures a dozen sunburst arc doppelgangers


Astronomers using the NASA/ESA Hubble Space Telescope have observed a galaxy in the distant regions of the Universe which appears duplicated at least 12 times on the night sky. This unique sight, created by strong gravitational lensing, helps astronomers get a better understanding of the cosmic era known as the epoch of reionisation.

Hubble captures a dozen sunburst arc doppelgangers
This recent picture from Hubble shows a galaxy nicknamed the Sunburst Arc that has been split into a kaleidoscope
 illusion of no fewer than 12 images formed by a massive foreground cluster of galaxies 4.6 billion light-years away
[Credit: NASA, ESA and E. Rivera-Thorsen (Institute of Theoretical Astrophysics Oslo, Norway)]
This new image from the NASA/ESA Hubble Space Telescope shows an astronomical object whose image is multiplied by the effect of strong gravitational lensing. The galaxy, nicknamed the Sunburst Arc, is almost 11 billion light-years away from Earth and has been lensed into multiple images by a massive cluster of galaxies 4.6 billion light-years away.

The mass of the galaxy cluster is large enough to bend and magnify the light from the more distant galaxy behind it. This process leads not only to a deformation of the light from the object, but also to a multiplication of the image of the lensed galaxy.


In the case of the Sunburst Arc the lensing effect led to at least 12 images of the galaxy, distributed over four major arcs. Three of these arcs are visible in the top right of the image, while one counterarc is visible in the lower left -- partially obscured by a bright foreground star within the Milky Way.

Hubble uses these cosmic magnifying glasses to study objects otherwise too faint and too small for even its extraordinarily sensitive instruments. The Sunburst Arc is no exception, despite being one of the brightest gravitationally lensed galaxies known.

This video shows an artist’s impression of the phenomenon of gravitational lensing 
[Credit: ESA/Hubble, M. Kornmesser]

The lens makes various images of the Sunburst Arc between 10 and 30 times brighter. This allows Hubble to view structures as small as 520 light-years across -- a rare detailed observation for an object that distant. This compares reasonably well with star forming regions in galaxies in the local Universe, allowing astronomers to study the galaxy and its environment in great detail.

Hubble's observations showed that the Sunburst Arc is an analogue of galaxies which existed at a much earlier time in the history of the Universe: a period known as the epoch of reionisation -- an era which began only 150 million years after the Big Bang.


The epoch of reionisation was a key era in the early Universe, one which ended the "dark ages", the epoch before the first stars were created when the Universe was dark and filled with neutral hydrogen. Once the first stars formed, they started to radiate light, producing the high-energy photons required to ionise the neutral hydrogen.

This converted the intergalactic matter into the mostly ionised form in which it exists today. However, to ionise intergalactic hydrogen, high-energy radiation from these early stars would have had to escape their host galaxies without first being absorbed by interstellar matter. So far only a small number of galaxies have been found to "leak" high-energy photons into deep space. How this light escaped from the early galaxies remains a mystery.

The analysis of the Sunburst Arc helps astronomers to add another piece to the puzzle -- it seems that at least some photons can leave the galaxy through narrow channels in a gas rich neutral medium. This is the first observation of a long-theorised process. While this process is unlikely to be the main mechanism that led the Universe to become reionised, it may very well have provided a decisive push.

Source: ESA/Hubble Information Center [November 07, 2019]



* This article was originally published here

Crew Preps for Friday Spacewalk During Continuous Science













ISS - Expedition 61 Mission patch.

November 12, 2019

The International Space Station’s cosmic particle detector, in operation since 2011, will get its first repair job during a series of spacewalks set to start this Friday. The Expedition 61 crew is gearing up for the spacewalk while ensuring ongoing advanced space research.

Commander Luca Parmitano of ESA (European Space Agency) will lead at least four excursions into the vacuum of space to upgrade the Alpha Magnetic Spectrometer (AMS). NASA Flight Engineer Andrew Morgan will assist the commander as they cut and reconnect fluid lines on the AMS’ thermal control system. The AMS captures cosmic particles and measures their electrical charge in its search for antimatter and dark matter.


Image above: Astronauts (from left) Luca Parmitano, Christina Koch and Andrew Morgan are pictured at the robotics workstation inside the cupola, the International Space Station’s “window to the world.” Image Credit: NASA.

NASA TV begins its live spacewalk coverage Friday at 5:30 a.m. EST. Parmitano and Morgan will set their U.S. spacesuits to battery power at 7:05 a.m. signifying the start of their spacewalk.

NASA astronauts Jessica Meir and Christina Koch will support the duo on Friday. Meir will be in charge of the Canadarm2 robotic arm while Koch manages the U.S. spacesuits. All four astronauts gathered today and reviewed robotics procedures for the spacewalk repairs.


Image above: This picture, taken by NASA astronaut Ron Garan during a spacewalk on July 12, 2011, shows the International Space Station with space shuttle Atlantis docked at the edge of the frame on the far right and a Russian Soyuz spacecraft docked to Pirs, below the sun. In the foreground is the Alpha Magnetic Spectrometer (AMS) experiment installed during the STS-134 mission. AMS is a state-of-the-art particle physics detector designed to use the unique environment of space to advance knowledge of the universe and lead to the understanding of the universe's origin by searching for antimatter and dark matter, and measuring cosmic rays. Image Credits: NASA/Ron Garan.

Life science and space physics also took up a portion of the crew’s schedule today. Koch checked out hardware on a 3-D bioprinter and watered plants as Meir fed lab mice. Morgan and Parmitano serviced biology and fluids research gear.

In the Russian segment of the station, a pair of cosmonauts packed a resupply ship for its Nov. 29 departure while working science and life support maintenance. Flight Engineer Alexander Skvortsov researched plasma crystals for an experiment that may inform future spacecraft designs. Oleg Skripochka checked the Zarya module’s power supply system before plumbing work and computer maintenance.

Related links:

Expedition 61: https://www.nasa.gov/mission_pages/station/expeditions/expedition61/index.html

Alpha Magnetic Spectrometer (AMS): https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=729

NASA TV: https://www.nasa.gov/multimedia/nasatv/index.html

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

3-D bioprinter: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=7599

Lab mice: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7906

Plasma crystals: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1192

Zarya module: https://www.nasa.gov/mission_pages/station/structure/elements/zarya-cargo-module

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.ch

* This article was originally published here

Galactic fountains and carousels: order emerging from chaos


Scientists from Germany and the United States have unveiled the results of a newly-completed, state of the art simulation of the evolution of galaxies. TNG50 is the most detailed large-scale cosmological simulation yet. It allows researchers to study in detail how galaxies form, and how they have evolved since shortly after the Big Bang. For the first time, it reveals that the geometry of the cosmic gas flows around galaxies determines galaxies' structures, and vice versa. The researchers publish their results in the journal Monthly Notices of the Royal Astronomical Society.

Galactic fountains and carousels: order emerging from chaos
Images of the optical light emitted by the stars of 16 galaxies from the TNG50 simulation. Each galaxy
is seen face-on or from the top (top sub panels), and edge-on or from the side (lower sub panels)
 [Credit: D. Nelson (MPA) and the IllustrisTNG team]
Astronomers running cosmological simulations face a fundamental trade-off: with finite computing power, typical simulations so far have been either very detailed or have spanned a large volume of virtual space, but have so far not been able to do both. Detailed simulations with limited volumes can model no more than a few galaxies, making statistical deductions difficult. Large-volume simulations, in turn, typically lack the details necessary to reproduce many of the small-scale properties we observe in our own Universe, reducing their predictive power.


The TNG50 simulation, which has just been published, manages to avoid this trade-off. For the first time, it combines the idea of a large-scale cosmological simulation - a Universe in a box - with the computational resolution of "zoom" simulations, at a level of detail that had previously only been possible for studies of individual galaxies.

In a simulated cube of space that is more than 230 million light-years across, TNG50 can discern physical phenomena that occur on scales one million times smaller, tracing the simultaneous evolution of thousands of galaxies over 13.8 billion years of cosmic history. It does so with more than 20 billion particles representing dark (invisible) matter, stars, cosmic gas, magnetic fields, and supermassive black holes. The calculation itself required 16,000 cores on the Hazel Hen supercomputer in Stuttgart, working together, 24/7, for more than a year - the equivalent of fifteen thousand years on a single processor, making it one of the most demanding astrophysical computations to date.

The formation of a single massive galaxy through time, from early cosmic epochs until the present day, in the TNG50 
cosmic simulation. The main panel shows the density of the cosmic gas (high in white, low in black). Insets show 
large-scale dark matter and then gas (lower left), and small-scale stellar and gaseous distributions (lower right). 
This TNG50 galaxy will be similar in mass and shape to Andromeda (M31) by the time the movie reaches the 
current epoch. Its progenitor experiences rapid star formation in a turbulent gas reservoir which settles into 
an ordered disc after a couple of billion years of cosmic evolution. A rather quiet late time assembly history 
without major mergers allows the galaxy to relax into an equilibrium balance of gas outflows from supernova 
explosions and gas accretion from its surroundings [Credit: D. Nelson (MPA) and the IllustrisTNG team]

The first scientific results from TNG50 are published by a team led by Dr Annalisa Pillepich (Max Planck Institute for Astronomy, Heidelberg) and Dr Dylan Nelson (Max Planck Institute for Astrophysics, Garching) and reveal unforeseen physical phenomena. According to Nelson: "Numerical experiments of this kind are particularly successful when you get out more than you put in. In our simulation, we see phenomena that had not been programmed explicitly into the simulation code. These phenomena emerge in a natural fashion, from the complex interplay of the basic physical ingredients of our model universe."


TNG50 features two prominent examples for this kind of emergent behaviour. The first concerns the formation of "disc" galaxies like our own Milky Way. Using the simulation as a time machine to rewind the evolution of cosmic structure, researchers have seen how the well-ordered, rapidly rotating disc galaxies (which are common in our nearby Universe) emerge from chaotic, disorganised, and highly turbulent clouds of gas at earlier epochs.

As the gas settles down, newborn stars are typically found on more and more circular orbits, eventually forming large spiral galaxies - galactic carousels. Annalisa Pillepich explains: "In practice, TNG50 shows that our own Milky Way galaxy with its thin disc is at the height of galaxy fashion: over the past 10 billion years, at least those galaxies that are still forming new stars have become more and more disc-like, and their chaotic internal motions have decreased considerably. The Universe was much messier when it was just a few billion years old!"

Galactic fountains and carousels: order emerging from chaos
Evolution over a few hundreds of million years (from top to bottom) of the gas around a galaxy from the TNG50 simulation,
with an active super massive black hole at its centre. The black hole at the centre of this galaxy is consuming gas from its
surroundings and in doing so is generating copious amounts of energy. The release of this energy produces ultra-fast winds,
which rapidly expand away from the galaxy and grow in size to become thousands of times larger than they started. These
black hole driven outflows achieve velocities of tens of thousands of kilometres per second, have temperatures exceeding
millions of degrees, and carry with them copious amounts of heavy elements such as oxygen, carbon, and iron. The four
columns show, from left to right, the evolving velocity, temperature, density, and heavy element content around the
galaxy. The galaxy itself is a cold (blue, second column), dense (yellow, third column) disc of star-forming gas visible
as a small, vertical slab in the very centre of each image [Credit: D. Nelson (MPA) and the IllustrisTNG team]


As these galaxies flatten out, researchers found another emergent phenomenon, involving the high-speed outflows and winds of gas flowing out of galaxies. This launched as a result of the explosions of massive stars (supernovae) and activity from supermassive black holes found at the heart of galaxies. Galactic gaseous outflows are initially also chaotic and flow away in all directions, but over time, they begin to become more focused along a path of least resistance.

In the late universe, flows out of galaxies take the form of two cones, emerging in opposite directions - like two ice cream cones placed tip to tip, with the galaxy swirling at the centre. These flows of material slow down as they attempt to leave the gravitational well of the galaxy's halo of invisible - or dark - matter, and can eventually stall and fall back, forming a galactic fountain of recycled gas. This process redistributes gas from the centre of a galaxy to its outskirts, further accelerating the transformation of the galaxy itself into a thin disc: galactic structure shapes galactic fountains, and vice versa.

The team of scientists creating TNG50 (based at Max-Planck-Institutes in Garching and Heidelberg, Harvard University, MIT, and the Center for Computational Astrophysics (CCA)) will eventually release all simulation data to the astronomy community at large, as well as to the public. This will allow astronomers all over the world to make their own discoveries in the TNG50 universe - and possibly find additional examples of emergent cosmic phenomena, of order emerging from chaos.

Source: Royal Astronomical Society [November 07, 2019]



* This article was originally published here

To the Moon and Beyond: Why Our SLS Rocket Is Designed for Deep Space

It will take incredible power to send the first woman and the next man to the Moon’s South Pole by 2024.  That’s where America’s Space Launch System (SLS) rocket comes in to play.

Providing more payload mass, volume capability and energy to speed missions through deep space than any other rocket, our SLS rocket, along with our lunar Gateway and Orion spacecraft, creates the backbone for our deep space exploration and Artemis lunar mission goals.

Here’s why our SLS rocket is a deep space rocket like no other:

It’s a heavy lifter

The Artemis missions will send humans 280,000 miles away from Earth. That’s 1,000 times farther into space than the International Space Station. To accomplish that mega feat, you need a rocket that’s designed to lift — and lift heavy. With help from a dynamic core stage — the largest stage we have ever built — the 5.75-million-pound SLS rocket can propel itself off the Earth. This includes the 57,000 pounds of cargo that will go to the Moon. To accomplish this, SLS will produce 15% more thrust at launch and during ascent than the Saturn V did for the Apollo Program.

We have the power 

Where do our rocket’s lift and thrust capabilities come from? If you take a peek under our powerful rocket’s hood, so to speak, you’ll find a core stage with four RS-25 engines that produce more than 2 million pounds of thrust alongside two solid rocket boosters that each provide another 3.6 million pounds of thrust power. It’s a bold design. Together, they provide an incredible 8.8 million pounds of thrust to power the Artemis missions off the Earth. The engines and boosters are modified heritage hardware from the Space Shuttle Program, ensuring high performance and reliability to drive our deep space missions.

A rocket with style

While our rocket’s core stage design will remain basically the same for each of the Artemis missions, the SLS rocket’s upper stage evolves to open new possibilities for payloads and even robotic scientific missions to worlds farther away than the Moon like Mars, Saturn and Jupiter. For the first three Artemis missions, our SLS rocket uses an interim cryogenic propulsion stage with one RL10 engine to send Orion to the lunar south pole. For Artemis missions following the initial 2024 Moon landing, our SLS rocket will have an exploration upper stage with bigger fuel tanks and four RL10 engines so that Orion, up to four astronauts and larger cargoes can be sent to the Moon, too. Additional core stages and upper stages will support either crewed Artemis missions, science missions or cargo missions for a sustained presence in deep space.

It’s just the beginning

Crews at our Michoud Assembly Facility in New Orleans are in the final phases of assembling the core stage for Artemis I— and are already working on assembly for Artemis II.

Through the Artemis program, we aim not just to return humans to the Moon, but to create a sustainable presence there as well. While there, astronauts will learn to use the Moon’s natural resources and harness our newfound knowledge to prepare for the horizon goal: humans on Mars.

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

With Mars Methane Mystery Unsolved, Curiosity Serves Scientists a New One: Oxygen













NASA - Mars Science Laboratory (MSL) patch.

Nov. 12, 2019

For the first time in the history of space exploration, scientists have measured the seasonal changes in the gases that fill the air directly above the surface of Gale Crater on Mars. As a result, they noticed something baffling: oxygen, the gas many Earth creatures use to breathe, behaves in a way that so far scientists cannot explain through any known chemical processes.

Over the course of three Mars years (or nearly six Earth years) an instrument in the Sample Analysis at Mars (SAM) portable chemistry lab inside the belly of NASA’s Curiosity rover inhaled the air of Gale Crater and analyzed its composition. The results SAM spit out confirmed the makeup of the Martian atmosphere at the surface: 95% by volume of carbon dioxide (CO2), 2.6% molecular nitrogen (N2), 1.9% argon (Ar), 0.16% molecular oxygen (O2), and 0.06% carbon monoxide (CO). They also revealed how the molecules in the Martian air mix and circulate with the changes in air pressure throughout the year. These changes are caused when CO2 gas freezes over the poles in the winter, thereby lowering the air pressure across the planet following redistribution of air to maintain pressure equilibrium. When CO2 evaporates in the spring and summer and mixes across Mars, it raises the air pressure.

Within this environment, scientists found that nitrogen and argon follow a predictable seasonal pattern, waxing and waning in concentration in Gale Crater throughout the year relative to how much CO2 is in the air. They expected oxygen to do the same. But it didn’t. Instead, the amount of the gas in the air rose throughout spring and summer by as much as 30%, and then dropped back to levels predicted by known chemistry in fall. This pattern repeated each spring, though the amount of oxygen added to the atmosphere varied, implying that something was producing it and then taking it away.

Credits: Melissa Trainer/Dan Gallagher/NASA Goddard

“The first time we saw that, it was just mind boggling,” said Sushil Atreya, professor of climate and space sciences at the University of Michigan in Ann Arbor. Atreya is a co-author of a paper on this topic published on November 12 in the Journal of Geophysical Research: Planets.

As soon as scientists discovered the oxygen enigma, Mars experts set to work trying to explain it. They first double- and triple-checked the accuracy of the SAM instrument they used to measure the gases: the Quadrupole Mass Spectrometer. The instrument was fine. They considered the possibility that CO2 or water (H2O) molecules could have released oxygen when they broke apart in the atmosphere, leading to the short-lived rise. But it would take five times more water above Mars to produce the extra oxygen, and CO2 breaks up too slowly to generate it over such a short time. What about the oxygen decrease? Could solar radiation have broken up oxygen molecules into two atoms that blew away into space? No, scientists concluded, since it would take at least 10 years for the oxygen to disappear through this process.


Animation above: NASA's Curiosity Mars rover imaged these drifting clouds on May 17, 2019, the 2,410th Martian day, or sol, of the mission, using its black-and-white Navigation Cameras (Navcams). Animation Credits: NASA/JPL-Caltech.

“We’re struggling to explain this,” said Melissa Trainer, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland who led this research. “The fact that the oxygen behavior isn’t perfectly repeatable every season makes us think that it’s not an issue that has to do with atmospheric dynamics. It has to be some chemical source and sink that we can’t yet account for.”

To scientists who study Mars, the oxygen story is curiously similar to that of methane. Methane is constantly in the air inside Gale Crater in such small quantities (0.00000004% on average) that it’s barely discernable even by the most sensitive instruments on Mars. Still, it’s been measured by SAM’s Tunable Laser Spectrometer. The instrument revealed that while methane rises and falls seasonally, it increases in abundance by about 60% in summer months for inexplicable reasons. (In fact, methane also spikes randomly and dramatically. Scientists are trying to figure out why.)

With the new oxygen findings in hand, Trainer’s team is wondering if chemistry similar to what’s driving methane’s natural seasonal variations may also drive oxygen’s. At least occasionally, the two gases appear to fluctuate in tandem.

“We’re beginning to see this tantalizing correlation between methane and oxygen for a good part of the Mars year,” Atreya said. “I think there’s something to it. I just don’t have the answers yet. Nobody does.”

Credits: Melissa Trainer/Dan Gallagher/NASA Goddard

Oxygen and methane can be produced both biologically (from microbes, for instance) and abiotically (from chemistry related to water and rocks). Scientists are considering all options, although they don’t have any convincing evidence of biological activity on Mars. Curiosity doesn't have instruments that can definitively say whether the source of the methane or oxygen on Mars is biological or geological. Scientists expect that non-biological explanations are more likely and are working diligently to fully understand them.

Trainer’s team considered Martian soil as a source of the extra springtime oxygen. After all, it’s known to be rich in the element, in the form of compounds such as hydrogen peroxide and perchlorates. One experiment on the Viking landers showed decades ago that heat and humidity could release oxygen from Martian soil. But that experiment took place in conditions quite different from the Martian spring environment, and it doesn’t explain the oxygen drop, among other problems. Other possible explanations also don’t quite add up for now. For example, high-energy radiation of the soil could produce extra O2 in the air, but it would take a million years to accumulate enough oxygen in the soil to account for the boost measured in only one spring, the researchers report in their paper.

Sunset at the Viking Lander 1 site, 1976. Image Credits: NASA/JPL

“We have not been able to come up with one process yet that produces the amount of oxygen we need, but we think it has to be something in the surface soil that changes seasonally because there aren’t enough available oxygen atoms in the atmosphere to create the behavior we see,” said Timothy McConnochie, assistant research scientist at the University of Maryland in College Park and another co-author of the paper.

The only previous spacecraft with instruments capable of measuring the composition of the Martian air near the ground were NASA’s twin Viking landers, which arrived on the planet in 1976. The Viking experiments covered only a few Martian days, though, so they couldn’t reveal seasonal patterns of the different gases. The new SAM measurements are the first to do so. The SAM team will continue to measure atmospheric gases so scientists can gather more detailed data throughout each season. In the meantime, Trainer and her team hope that other Mars experts will work to solve the oxygen mystery.

“This is the first time where we’re seeing this interesting behavior over multiple years. We don’t totally understand it,” Trainer said. “For me, this is an open call to all the smart people out there who are interested in this: See what you can come up with.”

Related links:

Geophysical Research: Planets: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019JE006175

Sample Analysis at Mars (SAM): https://mars.nasa.gov/msl/spacecraft/instruments/sam/

Mars Science Laboratory (MSL) "Curiosity": https://www.nasa.gov/mission_pages/msl/index.html

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

Greetings, Orbiter.ch

* This article was originally published here

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