NASA Astronomy Picture of the Day

March 18, 2025

LDN 1235: The Shark Nebula

There is no sea on Earth large enough to contain the Shark nebula. This predator apparition poses us no danger as it is composed only of interstellar gas and dust. Dark dust like that featured here is somewhat like cigarette smoke and created in the cool atmospheres of giant stars. After expelling gas and gravitationally recondensing, massive stars may carve intricate structures into their birth cloud using their high energy light and fast stellar winds as sculpting tools. The heat they generate evaporates the murky molecular cloud as well as causing ambient hydrogen gas to disperse and glow red. During disintegration, we humans can enjoy imagining these great clouds as common icons, like we do for water clouds on Earth. Including smaller dust nebulae such as Van den Bergh 149 & 150, the Shark nebula, sometimes cataloged as LDN 1235, spans about 15 light years and lies about 650 light years away toward the constellation of the King of Aethiopia (Cepheus).

https://apod.nasa.gov/apod/astropix.html

NASA’s SpaceX Crew-9 Re-Entry and Splashdown

March 18, 2025 5:11 p.m. EDT

Coverage of the Deorbit Burn and Splashdown of the NASA/SpaceX Dragon “Freedom” and the Crew-9 Crew for the First Available Return Opportunity (Hague, Gorbunov, Williams, Wilmore; deorbit burn scheduled at 5:11 p.m. EDT; splashdown for the first return opportunity scheduled at 5:57 p.m. EDT.

https://plus.nasa.gov/scheduled-video/coverage-of-the-deorbit-burn-and-splashdown-of-the-nasa-spacex-dragon/

https://www.youtube.com/watch?v=IDYt1l_7UvU

Chinese nuclear scientists identify flaw in Nasa’s lunar reactor design

Updated: 12:34pm, 18 Mar 2025

Chinese nuclear engineers have discovered a critical inefficiency issue in Nasa’s lunar nuclear reactor design – but, they claim, minor structural adjustments could slash fuel consumption by 75 per cent while boosting power output and longevity.

The findings, from a study led by Zhao Shouzhi, chief reactor designer at the China National Nuclear Corporation (CNNC), have already been integrated into China’s lunar base reactor programme – a development that could tilt the ongoing moon race in Beijing’s favour.

China’s lunar reactor, as outlined in the team’s peer-reviewed paper published in the Chinese journal Atomic Energy Science and Technology, can generate 40 kilowatts of electric power for more than a decade.

It leverages ring-shaped fuel rods and yttrium hydride moderators to overcome the limitations that plague traditional designs.

The dual-sided annular fuel rod – which can easily be produced by major nuclear companies including US firm Westinghouse – encases uranium dioxide pellets in stainless steel cladding, allowing simultaneous neutron moderation and heat dissipation on both inner and outer surfaces, according to Zhao and his colleagues.

Stable at extreme temperatures, the yttrium hydride moderator minimises the hydrogen leakage risks that destabilised earlier zirconium hydride systems.

This means that the Chinese reactor would only need a thin layer of beryllium reflectors to trap escaping neutrons, enhancing efficiency.

Dual cooling channels enable NaK-78 liquid metal flows through inner and outer fuel gaps, maintaining core temperatures below 600 degrees Celsius (1,112 Fahrenheit), while three boron carbide safety rods and eight rotary control drums provide redundant shutdown mechanisms.

By converting fast neutrons into thermal neutrons via yttrium hydride, China’s design can achieve sustained chain reactions with just 18.5kg of uranium-235 – around a quarter of the 70kg required by Nasa’s FSP fast reactor.

The fission surface power (FSP) reactor, developed under the first Trump administration’s lunar initiatives, relies on a fast neutron spectrum without moderators.

While compact, its cylindrical uranium fuel rods demand high enrichment levels and thick beryllium shielding to manage intense neutron flux, according to Zhao’s team.

They acknowledged that the FSP is a good design which has helped the development of the Chinese reactor.

But the US reactor has an eight-year lifespan cap – constrained by fuel swelling – and relies on single-path control drums for reactivity adjustments, lacking China’s dual shutdown safeguards.

“Our goal is to compete with the FSP,” Zhao and his colleagues wrote.

China’s breakthrough arrives amid Nasa’s workforce reductions under the Department of Government Efficiency (Doge), which recently closed Nasa’s Office of the Chief Scientist.

Nasa’s Artemis programme is also struggling under budgetary uncertainty, with some critical missions such as the VIPER rover being scrapped.

The design of the Chinese lunar reactor has also borrowed some important ideas from the TOPAZ-II reactor developed in the former Soviet Union, the scientists added.

https://www.scmp.com/news/china/science/article/3302163/chinese-nuclear-scientists-identify-flaw-nasas-lunar-reactor-design

NASA, Firefly Invite Media to Discuss End of Blue Ghost Moon Mission

Mar 17, 2025

NASA and Firefly Aerospace will host a news conference at 2 p.m. EDT Tuesday, March 18, from NASA’s Johnson Space Center in Houston to discuss the company’s successful Blue Ghost Mission 1 on the Moon’s surface.

Watch the news conference on NASA+. Learn how to watch NASA content through a variety of platforms, including social media.

U.S. media interested in participating in person or remotely must request accreditation by 5 p.m., Monday, March 17, by contacting the NASA Johnson newsroom at 281-483-5111 or jsccommu@mail.nasa.gov.

A copy of NASA’s media accreditation policy is online. To ask questions via phone, media must dial into the news conference no later than 15 minutes prior to the start of the call.

Firefly’s Blue Ghost lunar lander touched down March 2, on the Moon’s Mare Crisium basin.

The lander’s NASA payloads were activated, collected science data, and performed operations as part of NASA’s CLPS (Commercial Lunar Payload Services) initiative and Artemis campaign to establish a long-term lunar presence.

The mission is not designed to survive through the lunar night; however, Blue Ghost continued operations for five hours after lunar sunset on March 16.

Participants will include:

Joel Kearns, deputy associate administrator for exploration, Science Mission Directorate, NASA Headquarters in Washington

Jason Kim, CEO, Firefly Aerospace

Ray Allensworth, spacecraft program director, Firefly

Adam Schlesinger, CLPS project manager, NASA Johnson

The Blue Ghost Mission 1 mission launched at 1:11 a.m., Jan. 15, on a SpaceX Falcon 9 rocket from Launch Complex 39A at NASA’s Kennedy Space Center in Florida.

The lander delivered 10 NASA science investigations and technology demonstrations including testing and demonstrating lunar drilling technology, regolith (lunar rocks and soil) sample collection capabilities, global navigation satellite system abilities, radiation tolerant computing, and lunar dust mitigation.

The data captured will benefit humans on Earth in many ways, providing insights into how space weather and other cosmic forces impact our home planet.

NASA continues to work with multiple American companies to deliver science and technology to the lunar surface through the agency’s CLPS initiative.

This pool of companies may bid on NASA contracts for end-to-end lunar surface delivery services, including all payload integration and operations, launching from Earth and landing on the surface of the Moon.

Through the Artemis campaign, commercial robotic deliveries will perform science experiments, test technologies, and demonstrate capabilities on and around the Moon to help NASA explore in advance of Artemis Generation astronaut missions to the lunar surface, and ultimately crewed missions to Mars.

https://www.nasa.gov/news-release/nasa-firefly-invite-media-to-discuss-end-of-blue-ghost-moon-mission/

https://plus.nasa.gov/scheduled-video/nasa-and-firefly-final-update-on-blue-ghost-moon-mission/

New Modeling Assesses Age of Next Target Asteroid for NASA’s Lucy

Mar 17, 2025

Although NASA’s Lucy spacecraft’s upcoming encounter with the asteroid Donaldjohanson is primarily a mission rehearsal for later asteroid encounters, a new paper suggests that this small, main belt asteroid may have some surprises of its own.

New modeling indicates that Donaldjohanson may have been formed about 150 million years ago when a larger parent asteroid broke apart; its orbit and spin properties have undergone significant evolution since.

When the Lucy spacecraft flies by this approximately three-mile-wide space rock on April 20, 2025, the data collected could provide independent insights on such processes based on its shape, surface geology and cratering history.

“Based on ground-based observations, Donaldjohanson appears to be a peculiar object,” said Simone Marchi, deputy principal investigator for Lucy of Southwest Research Institute in Boulder, Colorado and lead author of the research published in The Planetary Science Journal.

“Understanding the formation of Donaldjohanson could help explain its peculiarities.”

“Data indicates that it could be quite elongated and a slow rotator, possibly due to thermal torques that have slowed its spin over time,” added David Vokrouhlický, a professor at the Charles University, Prague, and co-author of the research.

Lucy’s target is a common type of asteroid, composed of silicate rocks and perhaps containing clays and organic matter.

The new paper indicates that Donaldjohanson is a likely member of the Erigone collisional asteroid family, a group of asteroids on similar orbits that was created when a larger parent asteroid broke apart.

The family originated in the inner main belt not very far from the source regions of the near-Earth asteroids Bennu and Ryugu, recently visited respectively by NASA’s OSIRIS-REx and JAXA’s (Japan Aerospace Exploration Agency’s) Hayabusa2 missions.

“We can hardly wait for the flyby because, as of now, Donaldjohanson’s characteristics appear very distinct from Bennu and Ryugu. Yet, we may uncover unexpected connections,” added Marchi.

“It’s exciting to put together what we’ve been able to glean about this asteroid,” said Keith Noll, Lucy project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

“But Earth-based observing and theoretical models can only take us so far – to validate these models and get to the next level of detail we need close-up data. Lucy’s upcoming flyby will give us that.”

Donaldjohanson is named for the paleontologist who discovered Lucy, the fossilized skeleton of an early hominin found in Ethiopia in 1974, which is how the Lucy mission got its name.

Just as the Lucy fossil provided unique insights into the origin of humanity, the Lucy mission promises to revolutionize our knowledge of the origin of humanity’s home world.

Donaldjohanson is the only named asteroid so far to be visited while its namesake is still living.

“Lucy is an ambitious NASA mission, with plans to visit 11 asteroids in its 12-year mission to tour the Trojan asteroids that are located in two swarms leading and trailing Jupiter,” said SwRI’s Dr. Hal Levison, mission principal investigator at the Boulder, Colorado branch of Southwest Research Institute in San Antonio, Texas.

“Encounters with main belt asteroids not only provide a close-up view of those bodies but also allow us to perform engineering tests of the spacecraft’s innovative navigation system before the main event to study the Trojans.

These relics are effectively fossils of the planet formation process, holding vital clues to deciphering the history of our solar system.”

https://www.nasa.gov/centers-and-facilities/goddard/new-modeling-assesses-age-of-next-target-asteroid-for-nasas-lucy/

NASA’s Webb Images Young, Giant Exoplanets, Detects Carbon Dioxide

Mar 17, 2025

NASA’s James Webb Space Telescope has captured direct images of multiple gas giant planets within an iconic planetary system. HR 8799, a young system 130 light-years away, has long been a key target for planet formation studies.

The observations indicate that the well-studied planets of HR 8799 are rich in carbon dioxide gas.

This provides strong evidence that the system’s four giant planets formed much like Jupiter and Saturn, by slowly building solid cores that attract gas from within a protoplanetary disk, a process known as core accretion.

The results also confirm that Webb can infer the chemistry of exoplanet atmospheres through imaging. This technique complements Webb’s powerful spectroscopic instruments, which can resolve the atmospheric composition.

“By spotting these strong carbon dioxide features, we have shown there is a sizable fraction of heavier elements, like carbon, oxygen, and iron, in these planets’ atmospheres,” said William Balmer, of Johns Hopkins University in Baltimore.

“Given what we know about the star they orbit, that likely indicates they formed via core accretion, which is an exciting conclusion for planets that we can directly see.”

Balmer is the lead author of the study announcing the results published today in The Astrophysical Journal. Balmer and their team’s analysis also includes Webb’s observation of a system 97 light-years away called 51 Eridani.

Image A: HR 8799 (NIRCam Image)

Image B: 51 Eridani (NIRCam Image)

HR 8799 is a young system about 30 million years old, a fraction of our solar system’s 4.6 billion years.

Still hot from their tumultuous formation, the planets within HR 8799 emit large amounts of infrared light that give scientists valuable data on how they formed.

Giant planets can take shape in two ways: by slowly building solid cores with heavier elements that attract gas, just like the giants in our solar system, or when particles of gas rapidly coalesce into massive objects from a young star’s cooling disk, which is made mostly of the same kind of material as the star.

The first process is called core accretion, and the second is called disk instability. Knowing which formation model is more common can give scientists clues to distinguish between the types of planets they find in other systems.

“Our hope with this kind of research is to understand our own solar system, life, and ourselves in the comparison to other exoplanetary systems, so we can contextualize our existence,” Balmer said.

“We want to take pictures of other solar systems and see how they’re similar or different when compared to ours. From there, we can try to get a sense of how weird our solar system really is—or how normal.”

Image C: Young Gas Giant HR 8799 e (NIRCam Spectrum)

Of the nearly 6,000 exoplanets discovered, few have been directly imaged, as even giant planets are many thousands of times fainter than their stars.

The images of HR 8799 and 51 Eridani were made possible by Webb’s NIRCam (Near-Infrared Camera) coronagraph, which blocks light from bright stars to reveal otherwise hidden worlds.

This technology allowed the team to look for infrared light emitted by the planets in wavelengths that are absorbed by specific gases.

The team found that the four HR 8799 planets contain more heavy elements than previously thought.

The team is paving the way for more detailed observations to determine whether objects they see orbiting other stars are truly giant planets or objects such as brown dwarfs, which form like stars but don’t accumulate enough mass to ignite nuclear fusion.

“We have other lines of evidence that hint at these four HR 8799 planets forming using this bottom-up approach” said Laurent Pueyo, an astronomer at the Space Telescope Science Institute in Baltimore, who co-led the work.

“How common is this for planets we can directly image? We don't know yet, but we're proposing more Webb observations to answer that question.”

“We knew Webb could measure colors of the outer planets in directly imaged systems,” added Rémi Soummer, director of STScI’s Russell B. Makidon Optics Lab and former lead for Webb coronagraph operations.

“We have been waiting for 10 years to confirm that our finely tuned operations of the telescope would also allow us to access the inner planets. Now the results are in and we can do interesting science with it.”

https://science.nasa.gov/missions/webb/nasas-webb-images-young-giant-exoplanets-detects-carbon-dioxide/

https://webbtelescope.org/contents/news-releases/2025/news-2025-114

https://iopscience.iop.org/article/10.3847/1538-3881/adb1c6

Williams and Wilmore Are Not the First Astronauts to Be Delayed in Space

March 18, 2025, 9:00 a.m. ET

The NASA astronauts Suni Williams and Butch Wilmore are finally on their way back to Earth after nine months at the International Space Station.

But they were not the first to stay unexpectedly in space (much) longer than planned.

Here are some other notable examples:

On May 18, 1991, Sergei Krikalev set off into space for a stay at the Mir, the Soviet Union’s space station at the time.

While Mr. Krikalev was up there, the Soviet Union disbanded, and he was asked to extend his stay by almost five months, in part a result of the country’s disintegration and money problems in Moscow.

(The episode turned Mr. Krikalev into a bit of a media celebrity, earning him the nickname “the last Soviet citizen”). He stayed in space for 313 days, returning on March 25, 1992.

In 2003, three astronauts — Ken Bowersox and Donald Pettit, both American, and Nikolai Budarin, a Russian — had to prolong their stay on the relatively new International Space Station by about three months.

While they were in space, a NASA space shuttle disintegrated as it re-entered Earth’s atmosphere and killed all seven astronauts on board in an incident that became known as the Columbia disaster.

As a safety measure, NASA suspended its space shuttle flights. Eventually, after more than five months in space, the three astronauts landed back on Earth in a Russian capsule in May 2003.

(Dr. Pettit, now 69, returned to the space station aboard a Russian vehicle last fall for another stay, and is scheduled to return to Earth in April.)

In 2022, the American astronaut Frank Rubio headed to the International Space Station for a six-month stay. Instead, he stayed just over a year — 371 days — in what became the longest single spaceflight for a U.S. astronaut.

In December 2022, after coolant leaked from the Russian spacecraft that was to be used to bring Mr. Rubio home, his return trip was delayed while a different spacecraft was sent to pick up him and two Russian astronauts.

Like people serving in the military, “You kind of grow up with the mind set of, ‘You have to be ready for the unexpected,’” he said in an interview last August, “because that’s a very common thing.”

https://www.nytimes.com/2025/03/18/science/astronauts-stuck-space.html

1st glacier declared dead from climate change seen in before and after images — Earth from space

March 18, 2025

Two satellite photos taken 33 years apart show the disappearance of a glacier in Iceland that was the first ice mass to be declared dead as a result of human-caused climate change.

Okjökull was a dome-shaped glacier situated around the summit crater on Ok (pronounced Auk), a 3,940-foot-tall (1,200 meters) shield volcano located 44 miles (71 kilometers) northwest of Reykjavík.

(The name Okjökull translates to "Ok glacier" in Icelandic.)

In 1901, Okjökull's ice covered an area of around 15 square miles (39 square kilometers), but when the first of the two satellite photos was taken in 1986, there was less than 1 square mile (2.6 square km) of ice left.

By the time the second image was captured in 2019, the ice covered less than 0.4 square miles (1 square km), according to NASA's Earth Observatory.

The glacier was declared dead in 2014, when Icelandic glaciologists revealed that the ice had become so thin that it was no longer being slowly pulled down the mountain by gravity, meaning it had stopped moving for the first time in tens of thousands of years, according to a 2024 paper summarizing Okjökull's demise.

The glacier's death was showcased and explored in a 2018 short film titled "Not Ok," which was made by researchers from Rice University in Texas.

In August 2019, around 100 people, including researchers and politicians, attended a funeral for Okjökull near the summit of Ok, according to The Guardian.

During this ceremony, a commemorative plaque, inscribed with a message titled "A letter to the future," was placed near the summit.

It reads as follows: "Ok is the first Icelandic glacier to lose its status as a glacier. In the next 200 years all our glaciers are expected to follow the same path.

This monument is to acknowledge that we know what is happening and what needs to be done. Only you know if we did it."

The plaque also listed the concentration of carbon dioxide in the atmosphere, which was 415 parts per million at the time.

As of March 2025, the concentration is over 428 ppm, according to the National Oceanic and Atmospheric Administration.

In 2023, Iceland also created the world's first iceberg graveyard, where ice-like headstones were constructed for the 15 major glaciers listed on the Global Glacier Casualty List, all of which are either dead or critically endangered, according to the United Nations.

This list includes the Anderson Glacier in Washington state, which, in 2015, became the first U.S. glacier to be declared dead.

Because of inconsistent monitoring and debates about the true sizes of glaciers, it is unclear exactly how many glaciers have been lost due to climate change, according to the National Snow and Ice Data Center.

However, some researchers estimate that up to 10,000 glaciers of various sizes may have already been lost to climate change, The Washington Post reported in 2024.

https://www.livescience.com/planet-earth/climate-change/1st-glacier-declared-dead-from-climate-change-seen-in-before-and-after-images-earth-from-space

>>22781144

chekt

The internet is already acting funky, seems like blackout territory.