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By NASA
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Researchers think meltwater beneath Martian ice could support microbial life.
The white material seen within this Martian gully is believed to be dusty water ice. Scientists believe this kind of ice could be an excellent place to look for microbial life on Mars today. This image, showing part of a region called Dao Vallis, was captured by NASA’s Mars Reconnaissance Orbiter in 2009.NASA/JPL-Caltech/University of Arizona These holes, captured on Alaska’s Matanuska Glacier in 2012, are formed by cryoconite — dust particles that melt into the ice over time, eventually forming small pockets of water below the glacier’s surface. Scientists believe similar pockets of water could form within dusty water ice on Mars.Kimberly Casey CC BY-NC-SA 4.0 While actual evidence for life on Mars has never been found, a new NASA study proposes microbes could find a potential home beneath frozen water on the planet’s surface.
Through computer modeling, the study’s authors have shown that the amount of sunlight that can shine through water ice would be enough for photosynthesis to occur in shallow pools of meltwater below the surface of that ice. Similar pools of water that form within ice on Earth have been found to teem with life, including algae, fungi, and microscopic cyanobacteria, all of which derive energy from photosynthesis.
“If we’re trying to find life anywhere in the universe today, Martian ice exposures are probably one of the most accessible places we should be looking,” said the paper’s lead author, Aditya Khuller of NASA’s Jet Propulsion Laboratory in Southern California.
Mars has two kinds of ice: frozen water and frozen carbon dioxide. For their paper, published in Nature Communications Earth & Environment, Khuller and colleagues looked at water ice, large amounts of which formed from snow mixed with dust that fell on the surface during a series of Martian ice ages in the past million years. That ancient snow has since solidified into ice, still peppered with specks of dust.
Although dust particles may obscure light in deeper layers of the ice, they are key to explaining how subsurface pools of water could form within ice when exposed to the Sun: Dark dust absorbs more sunlight than the surrounding ice, potentially causing the ice to warm up and melt up to a few feet below the surface.
The white edges along these gullies in Mars’ Terra Sirenum are believed to be dusty water ice. Scientists think meltwater could form beneath the surface of this kind of ice, providing a place for possible photosynthesis. This is an enhanced-color image; the blue color would not actually be perceptible to the human eye.NASA/JPL-Caltech/University of Arizona Mars scientists are divided about whether ice can actually melt when exposed to the Martian surface. That’s due to the planet’s thin, dry atmosphere, where water ice is believed to sublimate — turn directly into gas — the way dry ice does on Earth. But the atmospheric effects that make melting difficult on the Martian surface wouldn’t apply below the surface of a dusty snowpack or glacier.
Thriving Microcosms
On Earth, dust within ice can create what are called cryoconite holes — small cavities that form in ice when particles of windblown dust (called cryoconite) land there, absorb sunlight, and melt farther into the ice each summer. Eventually, as these dust particles travel farther from the Sun’s rays, they stop sinking, but they still generate enough warmth to create a pocket of meltwater around them. The pockets can nourish a thriving ecosystem for simple lifeforms..
“This is a common phenomenon on Earth,” said co-author Phil Christensen of Arizona State University in Tempe, referring to ice melting from within. “Dense snow and ice can melt from the inside out, letting in sunlight that warms it like a greenhouse, rather than melting from the top down.”
Christensen has studied ice on Mars for decades. He leads operations for a heat-sensitive camera called THEMIS (Thermal Emission Imaging System) aboard NASA’s 2001 Mars Odyssey orbiter. In past research, Christensen and Gary Clow of the University of Colorado Boulder used modeling to demonstrate how liquid water could form within dusty snowpack on the Red Planet. That work, in turn, provided a foundation for the new paper focused on whether photosynthesis could be possible on Mars.
In 2021, Christensen and Khuller co-authored a paper on the discovery of dusty water ice exposed within gullies on Mars, proposing that many Martian gullies form by erosion caused by the ice melting to form liquid water.
This new paper suggests that dusty ice lets in enough light for photosynthesis to occur as deep as 9 feet (3 meters) below the surface. In this scenario, the upper layers of ice prevent the shallow subsurface pools of water from evaporating while also providing protection from harmful radiation. That’s important, because unlike Earth, Mars lacks a protective magnetic field to shield it from both the Sun and radioactive cosmic ray particles zipping around space.
The study authors say the water ice that would be most likely to form subsurface pools would exist in Mars’ tropics, between 30 degrees and 60 degrees latitude, in both the northern and southern hemispheres.
Khuller next hopes to re-create some of Mars’ dusty ice in a lab to study it up close. Meanwhile, he and other scientists are beginning to map out the most likely spots on Mars to look for shallow meltwater — locations that could be scientific targets for possible human and robotic missions in the future.
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Andrew Good
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-2433
andrew.c.good@jpl.nasa.gov
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NASA Headquarters, Washington
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Last Updated Oct 17, 2024 Related Terms
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By European Space Agency
ESA’s Mars Express has captured an astonishing array of landforms emerging from a thick winter blanket of frost as spring arrives in the south polar region of Mars. Some of these features are surprisingly dark compared with their icy surroundings, earning their nickname of ‘cryptic terrain’.
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By NASA
5 min read
NASA’s LRO: Lunar Ice Deposits are Widespread
Deposits of ice in lunar dust and rock (regolith) are more extensive than previously thought, according to a new analysis of data from NASA’s LRO (Lunar Reconnaissance Orbiter) mission. Ice would be a valuable resource for future lunar expeditions. Water could be used for radiation protection and supporting human explorers, or broken into its hydrogen and oxygen components to make rocket fuel, energy, and breathable air.
Prior studies found signs of ice in the larger permanently shadowed regions (PSRs) near the lunar South Pole, including areas within Cabeus, Haworth, Shoemaker and Faustini craters. In the new work, “We find that there is widespread evidence of water ice within PSRs outside the South Pole, towards at least 77 degrees south latitude,” said Dr. Timothy P. McClanahan of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author of a paper on this research published October 2 in the Planetary Science Journal.
The study further aids lunar mission planners by providing maps and identifying the surface characteristics that show where ice is likely and less likely to be found, with evidence for why that should be. “Our model and analysis show that greatest ice concentrations are expected to occur near the PSRs’ coldest locations below 75 Kelvin (-198°C or -325°F) and near the base of the PSRs’ poleward-facing slopes,” said McClanahan.
This illustration shows the distribution of permanently shadowed regions (in blue) on the Moon poleward of 80 degrees South latitude. They are superimposed on a digital elevation map of the lunar surface (grey) from the Lunar Orbiter Laser Altimeter instrument on board NASA’s Lunar Reconnaissance Orbiter spacecraft. NASA/GSFC/Timothy P. McClanahan “We can’t accurately determine the volume of the PSRs’ ice deposits or identify if they might be buried under a dry layer of regolith. However, we expect that for each surface 1.2 square yards (square meter) residing over these deposits there should be at least about five more quarts (five more liters) of ice within the surface top 3.3 feet (meter), as compared to their surrounding areas,” said McClanahan. The study also mapped where fewer, smaller, or lower-concentration ice deposits would be expected, occurring primarily towards warmer, periodically illuminated areas.
Ice could become implanted in lunar regolith through comet and meteor impacts, released as vapor (gas) from the lunar interior, or be formed by chemical reactions between hydrogen in the solar wind and oxygen in the regolith. PSRs typically occur in topographic depressions near the lunar poles. Because of the low Sun angle, these areas haven’t seen sunlight for up to billions of years, so are perpetually in extreme cold. Ice molecules are thought to be repeatedly dislodged from the regolith by meteorites, space radiation, or sunlight and travel across the lunar surface until they land in a PSR where they are entrapped by extreme cold. The PSR’s continuously cold surfaces can preserve ice molecules near the surface for perhaps billions of years, where they may accumulate into a deposit that is rich enough to mine. Ice is thought to be quickly lost on surfaces that are exposed to direct sunlight, which precludes their accumulations.
The team used LRO’s Lunar Exploration Neutron Detector (LEND) instrument to detect signs of ice deposits by measuring moderate-energy, “epithermal” neutrons. Specifically, the team used LEND’s Collimated Sensor for Epithermal Neutrons (CSETN) that has a fixed 18.6-mile (30-kilometer) diameter field-of-view. Neutrons are created by high-energy galactic cosmic rays that come from powerful deep-space events such as exploding stars, that impact the lunar surface, break up regolith atoms, and scatter subatomic particles called neutrons. The neutrons, which can originate from up to about a 3.3-foot (meter’s) depth, ping-pong their way through the regolith, running into other atoms. Some get directed into space, where they can be detected by LEND. Since hydrogen is about the same mass as a neutron, a collision with hydrogen causes the neutron to lose relatively more energy than a collision with most common regolith elements. So, where hydrogen is present in regolith, its concentration creates a corresponding reduction in the observed number of moderate-energy neutrons.
“We hypothesized that if all PSRs have the same hydrogen concentration, then CSETN should proportionally detect their hydrogen concentrations as a function of their areas. So, more hydrogen should be observed towards the larger-area PSRs,” said McClanahan.
The model was developed from a theoretical study that demonstrated how similarly hydrogen-enhanced PSRs would be detected by CSETNs fixed-area field-of-view. The correlation was demonstrated using the neutron emissions from 502 PSRs with areas ranging from 1.5 square miles (4 km2) to 417 square miles (1079 km2) that contrasted against their surrounding less hydrogen-enhanced areas. The correlation was expectedly weak for the small PSRs but increased towards the larger-area PSRs.
The research was sponsored by the LRO project science team, NASA’s Goddard Space Flight Center’s Artificial Intelligence Working Group, and NASA grant award number 80GSFC21M0002. The study was conducted using NASA’s LRO Diviner radiometer and Lunar Orbiter Laser Altimeter instruments. The LEND instrument was developed by the Russian Space Agency, Roscosmos by its Space Research Institute (IKI). LEND was integrated to the LRO spacecraft at the NASA Goddard Space Flight Center. LRO is managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, for the Science Mission Directorate at NASA Headquarters in Washington.
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Last Updated Oct 03, 2024 Editor wasteigerwald Contact wasteigerwald william.a.steigerwald@nasa.gov Location Goddard Space Flight Center Related Terms
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By NASA
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
This image, taken from a data visualization, shows Arctic sea ice minimum extent on September 11, 2024. The yellow boundary shows the minimum extent averaged over the 30-year period from 1981 to 2010. Download high-resolution video and images from NASA’s Scientific Visualization Studio: https://svsdev.gsfc.nasa.gov/5382NASA’s Scientific Visualization Studio/Trent L. Schindler Arctic sea ice retreated to near-historic lows in the Northern Hemisphere this summer, likely melting to its minimum extent for the year on Sept.11, 2024, according to researchers at NASA and the National Snow and Ice Data Center (NSIDC). The decline continues the decades-long trend of shrinking and thinning ice cover in the Arctic Ocean.
The amount of frozen seawater in the Arctic fluctuates during the year as the ice thaws and regrows between seasons. Scientists chart these swings to construct a picture of how the Arctic responds over time to rising air and sea temperatures and longer melting seasons. Over the past 46 years, satellites have observed persistent trends of more melting in the summer and less ice formation in winter.
This summer, Arctic sea ice decreased to a its minimum extent on September 11, 2024. According to the National Snow and Ice Data Center this is the 7th lowest in the satellite record). The decline continues the long-term trend of shrinking ice cover in the Arctic Ocean.
Credit: NASA’s Goddard Space Flight Center Tracking sea ice changes in real time has revealed wide-ranging impacts, from losses and changes in polar wildlife habitat to impacts on local communities in the Arctic and international trade routes.
This year, Arctic sea ice shrank to a minimal extent of 1.65 million square miles (4.28 million square kilometers). That’s about 750,000 square miles (1.94 million square kilometers) below the 1981 to 2010 end-of-summer average of 2.4 million square miles (6.22 million square kilometers). The difference in ice cover spans an area larger than the state of Alaska. Sea ice extent is defined as the total area of the ocean with at least 15% ice concentration.
Seventh-Lowest in Satellite Record
This year’s minimum remained above the all-time low of 1.31 million square miles (3.39 million square kilometers) set in September 2012. While sea ice coverage can fluctuate from year to year, it has trended downward since the start of the satellite record for ice in the late 1970s. Since then, the loss of sea ice has been about 30,000 square miles (77,800 square kilometers) per year, according to NSIDC.
Scientists currently measure sea ice extent using data from passive microwave sensors aboard satellites in the Defense Meteorological Satellite Program, with additional historical data from the Nimbus-7 satellite, jointly operated by NASA and the National Oceanic and Atmospheric Administration (NOAA).
Today, the overwhelming majority of ice in the Arctic Ocean is thinner, first-year ice, which is less able to survive the warmer months. There is far, far less ice that is three years or older now,
Nathan Kurtz
Chief, NASA's Cryospheric Sciences Laboratory
Sea ice is not only shrinking, it’s getting younger, noted Nathan Kurtz, lab chief of NASA’s Cryospheric Sciences Laboratory at the agency’s Goddard Space Flight Center in Greenbelt, Maryland.
“Today, the overwhelming majority of ice in the Arctic Ocean is thinner, first-year ice, which is less able to survive the warmer months. There is far, far less ice that is three years or older now,” Kurtz said.
Ice thickness measurements collected with spaceborne altimeters, including NASA’s ICESat and ICESat-2 satellites, have found that much of the oldest, thickest ice has already been lost. New research out of NASA’s Jet Propulsion Laboratory in Southern California shows that in the central Arctic, away from the coasts, fall sea ice now hovers around 4.2 feet (1.3 meters) thick, down from a peak of 8.8 feet (2.7 meters) in 1980.
Another Meager Winter Around Antarctica
Sea ice in the southern polar regions of the planet was also low in 2024. Around Antarctica, scientists are tracking near record-low sea ice at a time when it should have been growing extensively during the Southern Hemisphere’s darkest and coldest months.
Ice around the continent is on track to be just over 6.6 million square miles (16.96 million square kilometers). The average maximum extent between 1981 and 2010 was 7.22 million square miles (18.71 million square kilometers).
The meager growth so far in 2024 prolongs a recent downward trend. Prior to 2014, sea ice in the Antarctic was increasing slightly by about 1% per decade. Following a spike in 2014, ice growth has fallen dramatically. Scientists are working to understand the cause of this reversal. The recurring loss hints at a long-term shift in conditions in the Southern Ocean, likely resulting from global climate change.
“While changes in sea ice have been dramatic in the Arctic over several decades, Antarctic sea ice was relatively stable. But that has changed,” said Walt Meier, a sea ice scientist at NSIDC. “It appears that global warming has come to the Southern Ocean.”
In both the Arctic and Antarctic, ice loss compounds ice loss. This is due to the fact that while bright sea ice reflects most of the Sun’s energy back to space, open ocean water absorbs 90% of it. With more of the ocean exposed to sunlight, water temperatures rise, further delaying sea ice growth. This cycle of reinforced warming is called ice-albedo feedback.
Overall, the loss of sea ice increases heat in the Arctic, where temperatures have risen about four times the global average, Kurtz said.
About the Author
Sally Younger
Senior Science Writer
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Last Updated Sep 24, 2024 LocationGoddard Space Flight Center Related Terms
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By NASA
Linette Boisvert turned a childhood love of snow into a career as a sea ice scientist studying climate change.
Name: Linette Boisvert
Title: Assistant Lab Chief, Cryospheric Sciences Branch, and Deputy Project Scientist for the Aqua Satellite
Formal Job Classification: Sea Ice Scientist
Organization: Cryospheric Science Branch, Science Directorate (Code 615)
“When it snowed, school was cancelled so I loved winter weather, and I was fascinated how weather could impact our daily lives,” said Linette. “One of my undergraduate classes had a guest lecturer talk about the Arctic and that is when decided that I wanted to become an Arctic scientist.”Photo credit: NASA/Kyle Krabill What do you do and what is most interesting about your role here at Goddard?
As a sea ice scientist, I study interactions between the sea ice and the atmosphere. I’m interested in how the changing sea ice conditions and loss of Arctic ice are affecting the atmospheric conditions in the Artic.
Why did you become a sea ice scientist? What is your educational background?
I grew up in Maryland. When it snowed, school was cancelled so I loved winter weather, and I was fascinated how weather could impact our daily lives. One of my undergraduate classes had a guest lecturer talk about the Arctic and that is when decided that I wanted to become an Arctic scientist. This also coincided with the Arctic sea ice minimum in 2007, at the time, a record low.
In 2008, I got a B.S. in environmental science with a minor in math from the University of Maryland, Baltimore County (UMBC). I received my master’s and, in 2013, got a Ph.D. in atmospheric and oceanic sciences from the University of Maryland, College Park.
How did you come to Goddard?
My doctorate advisor worked at Goddard. In 2009, he brought me into Goddard’s lab to do my Ph.D. research. I became a post-doctorate in 2013, an assistant research scientist in 2016 (employed by UMD/ESSIC) and, in 2018, a civil servant.
Dr. Linette Boisvert is a sea ice scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md. Photo credit: NASA/Jeremy Harbeck What is the most interesting field work you do as the assistant lab chief of Goddard’s Cryospheric Sciences Branch?
From 2018 to 2020, I was the deputy project scientist for NASA’s largest and longest running airborne campaign, Operation IceBridge. This involved flying aircraft with scientific instruments over both land ice and sea ice in the Arctic and Antarctic. Every spring, we would set up a base camp in a U.S. Air Force base in Greenland and fly over parts of the sea ice over Greenland and the Arctic, and in the fall we would base out of places like Punta Arenas, Chile, and Hobart, Australia, to fly over the Antarctic.
We would fly low, at 1,500 feet above the surface. It is very, very cool to see the ice firsthand. It is so pretty, so vast, and complex. We would spend 12 hours a day on a plane just surveying the ice.
Being based out of Greenland is very remote. Everything is white. Everything looks like it is closer than it is. You do not have a point of reference for any perspective. It is very quiet. There is no background ambient noise. You do not hear bugs, birds, or cars, just quiet.
Our team was about 20 people. Other people live at the base. The campaigns lasted six to eight weeks. I was there about three to four weeks each time. Many of the group had been doing these campaigns for a decade. I felt like I had joined a family. In the evenings, we would often cook dinner together and play games. On days we could not fly, we would go on adventures together like visiting a glacier or hiking. We saw musk ox, Arctic fox, Arctic hares, and seals.
How did it feel to become the deputy project scientist for the Aqua satellite, which provided most of the data you used for your doctorate and publications?
In January 2023, I became the deputy project scientist for the Aqua satellite, which launched in 2002. Aqua measures the Earth’s atmospheric temperature, humidity, and trace gases. Most of my doctorate and publications used data from Aqua to look at how the sea ice loss in the Arctic is allowing for excess heat and moisture from the ocean to move into the atmosphere resulting in a warmer and wetter Arctic.
I am honored. I feel like I have come full circle. The team welcomed me into the mission and taught me a lot of things. I am grateful to be working with such a brilliant, hardworking team.
Who is your science hero?
My father encouraged me to get a doctorate in science. My father has a doctorate in computer science and math. He works at the National Institute of Standards and Technology. I wanted to be like him when I was growing up. I came close, working at NASA, another part of the federal government. My mother, a French pastry chef, always kept me well fed.
“We would fly low, at 1,500 feet above the surface,” said Linette. “It is very, very cool to see the ice firsthand. It is so pretty, so vast, and complex. We would spend 12 hours a day on a plane just surveying the ice.”Photo credit: NASA/John Sonntag My father is very proud of me. He thinks I am more of a superstar than he was at my age, but I do not believe it. My mother is also proud and continues to keep me well fed.
Who is your Goddard mentor?
Claire Parkinson, now an emeritus, was the project scientist for Aqua since its inception. When she retired, she encouraged me to apply for the deputy position. She had confidence in me which gave me the confidence to apply for the position. She is still always available to answer any questions. I am very thankful that she has been there for me throughout my career.
What advice do you give to those you mentor?
I recently began advising young scientists; one undergraduate student, two graduate students, and one post-doctoral scientist. We meet weekly as a group and have one-on-one meetings when appropriate. They share their progress on their work. Sometimes we practice presentations they are about to give.
It is sometimes hard starting out to think that you are smart because Goddard is full of so many smart people. I tell them that they are just as capable when it comes to their research topic. I tell them that they fit in well with the Goddard community. I want to create a comfortable, respectful, and inclusive environment so that they remain in science.
What do you do for fun?
I enjoy running and paddle boarding with my dog Remi, my long-haired dachshund. I enjoy reading. I love to travel and be around friends and family. But I do not enjoy cooking, so I do not bake French pastries like my mom.
Where do you see yourself in five years?
I hope to continue doing research including field work. It would be great if some of my students finished their studies and joined my lab. I hope that I am still making people proud of me.
What is your “six-word memoir”? A six-word memoir describes something in just six words.
Hard-working. Smart. Inquisitive. Adventurous. Kind. Happy.
By Elizabeth M. Jarrell
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Conversations With Goddard is a collection of Q&A profiles highlighting the breadth and depth of NASA’s Goddard Space Flight Center’s talented and diverse workforce. The Conversations have been published twice a month on average since May 2011. Read past editions on Goddard’s “Our People” webpage.
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Last Updated Sep 10, 2024 EditorMadison OlsonContactRob Garnerrob.garner@nasa.govLocationGoddard Space Flight Center Related Terms
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