Preparations for Next Moonwalk Simulations Underway (and Underwater)
NASA astronaut Anil Menon reviews procedures for emergency scenarios while aboard the International Space Station as part of his long-duration science and research mission.
Credit: NASA
Editor’s Note: This feature was updated Sept. 22, 2026, to note the time change for the in-flight call with students.
Students in New Hampshire will hear from NASA astronaut Anil Menon as he answers prerecorded STEM questions while aboard the International Space Station.
The Earth-to-space call will begin at 11:40 a.m. EDT Thursday, Sept. 24, and will stream live on the agency’s Learn With NASA YouTube channel.
This event is hosted by the McAuliffe-Shepard Discovery Center in Concord, New Hampshire, for students in grades K-12, and members of the community. This unique opportunity aims to deepen understanding of space exploration and enhance awareness of STEM careers.
Media interested in covering the event must RSVP no later than 5 p.m. EDT, Wednesday, Sept. 23, to Kelly Thompson at [email protected].
For more than 25 years, people have lived and worked continuously aboard the International Space Station, advancing scientific knowledge and making research breakthroughs not possible on Earth. The space station helps NASA understand and overcome the challenges of human spaceflight, expand commercial opportunities in low Earth orbit, and build on the foundation for long-duration missions to the Moon, as part of the Artemis program, and to Mars.
For more information on NASA in-flight calls, visit:
Images from NASA’s EPIC (Earth Polychromatic Imaging Camera) aboard the NOAA mission DSCOVR (Deep Space Climate Observatory) show Earth on the December and June solstices and the March and September equinoxes, illustrating how the tilt of Earth’s axis shifts the continent’s apparent positions through the year.
NASA Earth Observatory/Michala Garrison
Most kids learn in elementary school that the seasons are caused by Earth rotating on a tilted axis during its yearly orbit around the Sun. The substantial tilt, about 23.5 degrees, is thought to be the result of an ancient planetary body, Theia, smashing into Earth about 4.5 billion years ago, in the same cataclysmic collision that formed the Moon.
To visualize why Earth has seasons, imagine the planet as a spinning top tilted to one side. Around the June solstice, the Northern Hemisphere leans toward the Sun, bringing more direct sunlight and longer days. Around the December solstice, the Southern Hemisphere does the same. That’s why June ushers in summer and warm weather in the Northern Hemisphere, while December does so in the Southern Hemisphere.
The March and September equinoxes serve as the midpoints between these two seasonal extremes. On those days, the terminator—the boundary between the sunlit and dark sides of Earth—runs directly through both poles. As a result, the Northern and Southern Hemispheres receive almost the same amount of sunlight, and day and night are nearly equal in length.
What do the seasons look like from about one million miles away? That’s the view provided by NASA’s EPIC (Earth Polychromatic Imaging Camera) aboard the NOAA mission DSCOVR (Deep Space Climate Observatory). By maintaining an orbit that puts the spacecraft between the Sun and Earth roughly 1.6 million kilometers (1 million miles) from Earth, the camera has a nearly continuous view of the sunlit hemisphere. As Earth spins during the course of a day, EPIC captures a full-disk image of the planet’s sunlit face every few hours.
The four images above, taken at roughly the same time of day, show how EPIC’s view of the Western Hemisphere changes over the year, from the December solstice (upper left) to the March equinox (upper right), June solstice (lower left), and September equinox (lower right). The most striking difference is between the two solstices. In December, South America lies near the center of the disk and much of Antarctica is visible, while North America is partially out of view. In June, Earth’s tilt means the situation is reversed: the Northern Hemisphere and North America are more centered, Arctic sea ice comes into view, South America is offset, and Antarctica is completely out of view.
There are other notable differences among the four images. Earth looks slightly smaller during the March and September equinoxes, for instance. That’s because DSCOVR was tens of thousands of miles farther away from Earth on those dates than on the solstices. On December 21, 2023, DSCOVR was 1,447,327 kilometers (899,327 miles) from Earth compared with 1,561,901 kilometers (970,520 miles) on September 22, 2024.
The slight difference in Earth’s apparent size has nothing to do with Earth’s tilt. Instead, it occurs because DSCOVR follows a looping, three-dimensional path called a Lissajous orbit to keep the spacecraft near Lagrange point 1, where the combined gravitational pull of the Sun and Earth and the centrifugal pull of the satellite balance out, making it easier for engineers to maintain the spacecraft’s position without using much fuel. DSCOVR’s distance from Earth swings between its maximum and minimum roughly every three months, and the timing drifts throughout the year because of lunar influences and orbital maneuvers. In 2024, the orbit happened to put the spacecraft slightly farther from Earth at both equinoxes, but that is not always the case.
There’s one other notable way the images differ. Because of DSCOVR’s Lissajous orbit, the angle between the Sun, Earth, and satellite varies between 2 and 12 degrees, explained Alexander Marshak, the deputy project scientist for the DSCOVR mission. Earth appears as a fully illuminated disk at smaller angles and less rounded at larger angles, like a “bite” has been taken out, similar to a gibbous phase of the Moon. For this set of images, the September 22 image has a slightly lower angle (8.1°) than the December 21 image (10.3°), making it appear slightly rounder and fuller. The angle between the Sun, Earth, and satellite in the other two images is between 9° and 10°.
“You can see the subtle influence of the changing orbital geometry in these images,” Marshak said. “But the most obvious changes—the apparent location of the continents—are due to Earth’s tilt.”
EPIC’s vantage point offers a perspective that makes it easier to understand and visualize why Earth has seasons, but after more than a decade in space, the mission has also opened up new approaches to understanding and observing how daily and seasonal cycles play out on a planetary scale. It has collected more than a decade of diurnal and seasonal data on many key features on Earth, including vegetation, clouds, ice, snow, UV radiation, ocean color, and aerosols.
NASA Earth Observatory image by Michala Garrison, using data from DSCOVR EPIC.Story by Adam Voiland.
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Illustration showing how Earth’s tilt leads to the Northern and Southern Hemispheres receiving changing amounts of sunlight over the course of the year. At the equinoxes, neither hemisphere is more tilted toward the Sun, so both hemispheres receive the same amount of sunlight.
Credits: NASA/JPL-Caltech
Depending on your locale, equinoxes can be seen as harbingers of longer nights and gloomy weather, or promising beacons of nicer temperatures and more sunlight. Observing and predicting equinoxes is one of the earliest skills in humanity’s astronomical toolkit. Many ancient observatories around the world observed equinoxes along with the more pronounced solstices. These days, you don’t need your own observatory to know when an equinox occurs, since you’ll see it marked on your calendar twice a year! The word “equinox” originates from Latin, and translates to equal (equi-) night (-nox). But what exactly is an equinox?
An equinox occurs twice every year, in March and September. In 2026, the equinoxes will occur on March 20, at exactly 14:46 UTC (or 7:46 AM EDT), and again on September 23, at 00:05 UTC (or September 22, 2026, at 5:05 PM PDT). The equinox marks the exact moment when the center of the Sun crosses the plane of our planet’s equator. The day of an equinox, observers at the equator will see the Sun directly overhead at noon. After the March equinox, observers anywhere on Earth will see the Sun’s path in the sky continue its movement further north every day until the June solstice, after which it begins traveling south. The Sun crosses the equatorial plane again during the September equinox, and continues traveling south until the December solstice, when it heads back north once again. This movement is why some refer to the March equinox as the northward equinox and the September equinox as the southward equinox.
A full disk view of the earth from GOES 16, GOES East on the vernal Equinox.
NOAA/NASA
Our Sun shines equally on both the Northern and Southern Hemispheres during equinoxes, which is why they are the only times of the year when the Earth’s North and South Poles are simultaneously lit by sunlight. Notably, the length of day and night on the equinox isn’t precisely equal; the date for that split depends on your latitude, and may occur a few days earlier or later than the equinox itself. The complicating factors? Our Sun and atmosphere! The Sun itself is a sphere and not a point light source, so its edge is refracted by our atmosphere as it rises and sets, which adds several minutes of light to every day. The Sun doesn’t neatly wink on and off at sunrise and sunset like a light bulb, and so there isn’t a perfect split of day and night on the equinox – but it’s very close.
Equinoxes are associated with the changing seasons. In March, Northern Hemisphere observers welcome the longer, warmer days heralded by their vernal, or spring, equinox, but Southern Hemisphere observers note the shorter days – and longer, cooler nights – signaled by their autumnal, or fall, equinox. Come September, the reverse is true.
NASA’s Perseverance Mars rover used its Mastcam-Z camera to capture this 360-degree panorama of “Turquoise Bay,” a geologic area of interest in the “Margin Unit.” The 818 images used to create the natural-color panorama were captured between Oct. 5 and Oct. 16, 2023, the 933rd to 944th Martian days, or sols, of the mission.
Figure A is an enhanced-color version, in which color bands were processed to improve visual contrast and accentuate color differences.
NASA’s Jet Propulsion Laboratory, which is managed for the agency by Caltech in Pasadena, California, built and manages operations of the Perseverance rover. Arizona State University leads the operations of the Mastcam-Z instrument, working in collaboration with Malin Space Science Systems in San Diego, on the design, fabrication, testing, and operation of the cameras, and in collaboration with the Niels Bohr Institute of the University of Copenhagen on the design, fabrication, and testing of the calibration targets.
More than 9,000 people across 50 states registered for the 2026 Air Force Marathon, testing their mental and physical endurance across several race categories.
NASA astronaut and commander of the agency’s Artemis II mission, Reid Wiseman, a Baltimore native, takes a selfie with fans at an NFL game between the New Orleans Saints and the Baltimore Ravens at M&T Bank Stadium, Sunday, Sept. 20, 2026, in Baltimore.
NASA’s engagement at NFL games is part of the agency’s Inspiration Tour, aimed at strengthening connections between NASA and its partners and showcasing innovation in air and space in the lead up to the MAX POWER aerospace technology expo and airshow at the agency’s Kennedy Space Center in early November.
Preparations for Next Moonwalk Simulations Underway (and Underwater)
The Perseverance rover captured the data used in this panorama of the “Margin Unit,” a geologic area that hugs the inner edge of Jezero Crater’s rim, between Oct. 8 and Oct. 16, 2023.
NASA/JPL-Caltech/MSSS
When NASA’s Perseverance rover reached the inner edge of Mars’ Jezero Crater in September 2023, mission scientists were surprised by what they found. Called the “Margin Unit,” the geologic area stretches along the shoreline of an ancient Martian lake, so they expected sedimentary rocks, which would have formed as layers of sand piled on top of each other over millennia. Composed of clay and silt, sedimentary rocks on Earth are good at preserving past microbial life. The scientists were especially intrigued by strong signals of carbonate minerals detected by Mars orbiters. On Earth, carbonates frequently form in shallow ocean and lake environments capable of supporting life.
Instead, the rover team found igneous rock, which can form deep underground from magma or from volcanic activity at the surface. Igneous rocks are excellent record-keepers, particularly because mineral crystals within them preserve details about the precise moment they formed. In this case, they preserved an astonishingly complex record of water activity on early Mars. In fact, these rocks showed signs of having interacted with water on at least three separate occasions, with each encounter further altering their chemistry and appearance. The findings were published Monday in the journal Communications Earth & Environment.
The instrument behind the findings is SuperCam, which perches on the rover’s mast and determines the mineralogy of geologic features based on the light they reflect. When the science team spots an intriguing rock, they can send commands for SuperCam to fire its laser up to 21 feet (6.5 meters) away. The spectrum of the resulting plasma reveals the target’s chemistry. Perseverance has analyzed more than 185 bedrock targets across the unit this way.
“Before we arrived at the Margin Unit, the main hypothesis — derived from orbital observations — was that the carbonate seen from orbit formed from interaction with the lake that existed in Jezero Crater,” said Candice Bedford, a research scientist at Purdue University in West Lafayette, Indiana, and the study’s lead author. “But now we know that this location became a sort of crossroads for aqueous systems. The Margin Unit findings are important because Jezero Crater sits inside one of the largest exposures of carbonate on Mars, so what we learn here reaches well beyond this crater.”
Slow-cooling underground
Perseverance explored the Margin Unit across approximately 870 feet (265 meters) of elevation. At higher elevations, it found rock that was coarse-grained and crystalline — hallmarks of the mineral olivine — with almost no sign that water had ever touched it. Made of magnesium and iron, the area’s olivine unit formed in a body of magma deep underground, cooling slowly enough for its grains to grow large, and reached the surface only after the ground above it eroded away. Lower in the unit, on the lakebed, the rock looks transformed, as the olivine grains were fractured with silica between them.
Carbonate and silica minerals are an important signpost in the search for ancient life. When water interacts with olivine on Earth, the reaction can release hydrogen, which can be a food source for some microbes, and it leaves behind carbonate and silica, two minerals that lock in traces of the past existence of those microbes.
Multiple episodes
The Perseverance team can determine the sequence of the Margin Unit’s interactions with water, but not their age. On the first occasion water reached the rocks of the Margin Unit, carbon-dioxide-rich groundwater reacted with olivine, resulting in ridges of carbonate that run through the fractures in bedrock at low elevations. Today, these carbonate-filled fractures are left standing as the softer rock around them wears away.
The second time water reached the rocks may have been related to the lake that once existed in the crater.
“Some of the Margin Unit rocks also contain silica,” said Eleni Ravanis, a planetary scientist at the University of Hawaii at Manoa and a coauthor of the study. “Turning olivine into carbonate can leave silica behind, and we see more of that silica in rocks that sat below the water line.”
Last came a water event that generated mineral veins at one location in the eastern part of the Margin Unit, about 10 inches (25 centimeters) thick, creating minerals like calcium sulfate and fluorite. Finding fluorite is an important clue because it typically forms when hot water circulates through volcanic rocks, revealing that this area experienced a later, heated underground-water event.
“If there is one thing I have learned after 10 years working with Mars rovers, it is that Mars constantly throws surprises at you,” said Bedford. “It is very rare that things are as we expect them to be from orbital data. I hope this work helps reshape how scientists view the history of water in Jezero Crater and across Mars. Ultimately, I hope it helps planetary scientists reconstruct the changing climate and habitability of early Mars.”
More about Perseverance
A key objective of Perseverance’s mission on Mars is astrobiology, including the search for signs of ancient microbial life. The rover characterizes the planet’s geology and past climate and collects and stores Martian rock and regolith.
Managed for NASA by Caltech, Jet Propulsion Laboratory in Southern California built and manages operations of the Perseverance rover on behalf of the agency’s Science Mission Directorate as part of NASA’s Mars Exploration Program portfolio. SuperCam is co-led by Purdue University in Indiana, Los Alamos National Laboratory in New Mexico, and IRAP (Research Institute in Astrophysics and Planetology) and CNES (Centre National d’Etudes Spatiales) in Toulouse, France.
Johnson Space Center Sparks Curiosity at Houston’s 33rd Annual Japan Festival
On Sept. 12-13, NASA’s Johnson Space Center employees brought the excitement and wonder of space exploration to Houston’s Japan Festival at Hermann Park.
Attendees at the Japan Festival in Houston’s Hermann Park try on real astronaut gloves and a helmet while learning about NASA missions on Sept. 12, 2026.
NASA/Hailey Quist
For more than 30 years, the festival has immersed guests in traditional Japanese culture through food, dance, martial arts, music, and more, Johnson has supported the festival as an exhibitor for the past four years.
Johnson’s booth showcased the upcoming Artemis III mission and its crew, as well as NASA’s plans for the Moon Base. Display included models of NASA’s Orion spacecraft and the International Space Station, along with interactive exhibits featuring space food and a real astronaut glove and helmet for attendees to try on.
NASA’s Johnson Space Center volunteers share information about NASA missions with festival attendees.
NASA/Hailey Quist
Johnson employees interacted with over 3,000 festivalgoers, informing them about the agency’s current initiatives, handing out NASA stickers and pins, and inspiring the next generation of space explorers. According to Johnson employees, the highlight of the weekend was seeing the joy and excitement on the faces of children and adults as they explored the exhibits.
“It was amazing to see students as early as high school so passionate about NASA and asking questions on how to prepare for a NASA career,” said Brendan King, software engineer for Johnson’s Flight Dynamics Division.
Next to Johnson’s booth, JAXA (Japanese Aerospace Exploration Agency), displayed a model of the HTV-X1 cargo spacecraft, space food, and images of JAXA’s pressurized rover, which could support future crewed and uncrewed exploration on the Moon. JAXA astronaut Akihiko Hoshide also signed autographs and posed for pictures with festival attendees.
JAXA (Japan Aerospace Exploration Agency) astronaut Akihiko Hoshide signs autographs and poses for pictures with festivalgoers.
NASA/Hailey Quist
The proximity of the booths was no mistake, reflecting the long-standing partnership between NASA and JAXA. From the addition of the Kibo laboratory aboard the space station to Japan’s signing of the Artemis Accords and development of lunar surface hardware. NASA and JAXA’s commitment to innovation and international collaboration continues to advance exploration.
As the hub of human spaceflight, Johnson engages with the public through events like Japan Festival. These events give the Johnson community opportunities to share NASA’s history, ongoing work, and future missions. They also remind Houstonians that Giant Leaps Start Here, right in the heart of Houston.
Adults and kids enjoy the NASA booth and its exhibits.
NASA/Hailey Quist
Johnson employees hand out pins and educate attendees about NASA missions.
NASA/Hailey Quist
Guests enjoy their favorite astronauts at Johnson’s booth.
NASA/Hailey Quist
Johnson employees engage with festivalgoers at Houston’s Japan Festival.
NASA/Hailey Quist
Johnson employees pose for a selfie at Houston’s Japan Festival.
