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This post documents what we saw on our last day in Kruger, the day we had to leave and repair back to Hoedspruit.

First, you might like to see our accommodations at the Satara Rest Camp, which were lovely and inexpensive. Below is my own personal hut with a high thatched roof (thatching is quite a skill, and roofs have to be re-thatched every decade or two.

A view from the inside. I had two beds, a nice bathroom, and a fridge outside with a latch to keep the baboons out. Not to mention air-conditioning, which I didn’t need as it wasn’t hot.

My two beds:

And a view of the thatched roof seen while lying on one of the beds. As you can see from the first picture, the roof was high.

We were near the remains of the buffalo killed by lions, so we dropped by again. One of the lions was still around. Have a look: this is a male with its normal “tawny” color:

And when our guide Isaac told us there were white lions in the park (leucistic ones, not albinos), nothing would do for me except to see them. Given that there are only a few, the chances of that were small. However, Isaac had read on his “Kruger guides” restricted chat group that a white lion had been spotted about a mile north of Satara. So he went looking for it. Given his skills as a spotter, if it was anywhere near the roadside, he’d find it.

And he did!

Here’s one; note that it’s not pure white, but a light yellow, and clearly distinct in color from “regular” lions.  There’s one famous white lion in Kruger called “Casper” (undoubtedly after the ghost), but I’m not sure if this is Casper. It is, however, a male:

One would think that the whiteness might confer an adaptive disadvantage on these animals, either driving away regular lions who don’t like their color, or making these white ones visible to prey. But they don’t seem disabled. As Wikipedia notes:

White lions are not albinos. Their white color is called leucism, and is caused by an allele that is found at the same locus as the allele that causes albinism. It is thought, but not proven, that the allele is inherited in an autosomal recessive fashion.  They vary from blonde to near-white. This coloration does not appear to pose a disadvantage to their survival. White lions were considered to have been technically extinct in the wild between 1992 and 2004, when the Global White Lion Protection Trust achieved the first successful reintroduction of white lions to their natural habitat. These prides have continued to hunt and breed successfully in the wild, whilst other occurrences of white lion births have been reported in the greater Kruger region since then.

There’s more information:

In light of the recent decision by South Africa’s Department of Environmental Affairs (DEA) at CITES 2016, to continue to allow the hunting of captive bred lions (“canned hunting”), and the trade in lion bones from captive bred lions, the Global White Lion Protection Trust (WLT) asserts that the survival of lions in the Greater Kruger Park Region is likely to come under threat, and the white lion is the ideal capstone animal to help better protect all lions in the Greater Kruger Park Region.

I like to think this is Casper. But even if it isn’t, it was a great joy for me to see this animal thriving in the wild. Kudos to Isaac for not only making an effort to find it for me, but also to succeed in that effort!

And a “normal” tawny lion for comparison again. Note the dark mane and distinct brown color.

By this time the remains of the buffalo had been picked clean by both nearby lions and, of course, by vultures, seen below on the bones.  I’m not sure whether the spotted hyenas ever got a crack at this carcass:

A rare sight and one of my collection of “animals crossing the road.”  Lion crossing!  The cars, of course, are lined up to see the sight, which attests to how comfortable these lions are with humans—at least when they’re in cans.

The lion who crossed the road then found a comfortable perch on the other side, explaining “why did the lion cross the road?”:

Eventually we stopped at the Olifants Rest Camp to have breakfast. With a lovely view overlooking the Olifants River (a tributary of the Limpopo River), it has bungalows and would be a delightful place to stay, especially in the rainy summer season when the river must attract lots of wildlife. But if you want to stay there, reserve a year in advance.

It was blowing hard that day, and cold as well, but this brave dude was out there re-thatching a roof with no apparent protection from falling off:

And I got the breakfast I had dreamed of: one that had fried eggs and pap: the African equivalent of grits and eggs.  It was topped with a spicy tomato-y sauce generously larded with crispy fried cubes of pork. It was one of the best breakfasts I’ve ever had, and filled me up so much I couldn’t eat for the rest of the day:

On my way to the facilities, I took a selfie in the mirror:

This view of a thunder of hippos (yes, that’s one proper collective noun for a group of them) was probably taken from the Olipants rest camp, but I can’t remember.

We later came upon a dazzle of zebras (again, a proper collective noun).  I waited patiently with my camera focused on these three until I managed to get a shot of them all looking in my direction. What gorgeous animals!

A Red -crested korhaan (Lophotis ruficrista). I remembered this as a “Jewish bird” by thinking that its real name was the Red-crested Cohen.” It has a lovely pattern as described in Wikipedia:

The red-crested korhaan grows up to 50 cm (1.6 ft) in length with a maximal weight of 680 g (1.5 lb).  The feathering of the wings folded on the back is marked by V-formed patterns of a light cream color with some white at the sides. Breast feathers are black. Legs are pale yellow and feet gray.

Click the picture to enlarge it:

A herd of impala, this one apparently heavy on males (females don’t have horns):

. . . and a male impala crossing the road, probably to rejoin his herd.

You’ll know this species by now if you’ve been following my narrative. Look at the butt for confirmation:

This elephant has had a long drink of water from a cement pool, and the warthog was waiting patiently nearby for its turn to drink. But we waited and waited, and the elephant wasn’t sated. (They can take in 100 liters of water at one time.) So we left, hoping the warthog got a drink.

A journey of giraffe. That’s what you call a group of giraffes that is moving, but a group of stationary giraffes is called “a tower of giraffe”. These are appropriate terms.

And at least we reach the end of our journey in Kruger at the Orpen Gate. There are actually two exits, and at one of them you’re obliged to show your receipts showing you’ve actually paid the conservation fee for each day you’ve stayed.  When I took a photo after the first gate, the gatekeeper woman posted for me:

How sad to leave!

And the second gate, when we once again left the bush and entered “civilization”:

Will I go back again? I’d love to see the park when it’s green in summer, though it also rains then. But, as Stevie Nicks said, “I’m getting older, too.”  Who knows?

If you ever visit Kruger, you should definitely engage Isaac as your guide

Many thanks to Isaac, our guide/driver/spotter, shown below getting a coffee at the exit. Thanks too to Rosemary, who did a pile of work to organize this trip and my visit to Manyelete.

Oh, and I almost forgot.  Ozy went missing for a few days, and I didn’t get to see him after I returned from Kruger and before I came back to Cape Town. I was worried: after all, he’s a Senior Pig.

But he’s back again, reportedly in good nick. Here he is sleeping off his latest foraging bout (photos by Rosemary).

If you didn’t see the white lion in the last “spot the” picture, here’s your chance to find an easier cat. (And no wisecracks about how “the leopard is already spotted”)!

Here’s a picture taken from one of the “hides” in Kruger where you can spot wildlife from inside a shed with a viewing slit. Can you spot the leopard? I bet you can.

This, by the way, is the only leopard we saw in Kruger, though I got awesome views of one in Manyelete (see photos from that trip).

I got this tweet from Luana, who noted Chicago’s steep fall from grace in FIRE’s free-speech rankings for 2025. (“The College Pulse” also collaborated in the rankings.)

FIRE’s 2025 Campus Free Speech Rankings are out.

Harvard is once again the worst school on the list.

Columbia and New York University join it in the “abysmal” category.

Penn and Barnard are among the four “very poor” schools. pic.twitter.com/fJ5yenYiF7

— Steve McGuire (@sfmcguire79) September 5, 2024

Click the screenshot to see all 251 rated schools.

Here are the top ten. Note that the University of Chicago, once #1 for a long time and always in the top five, is no longer at the top. In fact, the top school, the University of Virginia, simply gets a “good” rating and a so-so score of 73.4 out of a hundred.

Where, oh where, is my school?  It’s a dismal #43, and rated only “slightly above average.”

The low score appears to reflect a big difference in the campus’s willingness to tolerate liberal vs. conservative speakers, and a high score in the degree of self-censorship that students practice.

This is very sad, for we can no longer even say we’re in the top ten, and Chicago’s reputation for being a bastion of “free speech” has taken a severe hit.

As for the bottom ten, well, Harvard is the worst, but now both NYU and Columbia have joined it with the rare “abysmal” rating:

All I can say is “oy vey!”, and that the administration is going to have to do some fast-stepping, for they used to tout our high ratings and now will have to confect some reasons why the rating system isn’t very good.

The Universe often puts on a good show for us down here on Earth but one of the best spectacles must be a meteor shower. We see them when particles, usually the remains of comets, fall through our atmosphere and cause the atmosphere to glow. We see them as a fast moving streak of light but a new paper has suggested that the meteor showers we see can explain the sizes of the particles that originally formed the comet from where they came. 

Comets are mostly composed of ice but with a little rock mixed in for good measure. They’ve often been called dirty snowballs to describe this mix of ice and rock. They travel around the Sun in elongated, elliptical orbits which bring them close to the Sun. The intense heat from the Sun causes the ice to instantly turn into a gas in a process known as sublimation which releases the trapped dust. The pressure from the Sun known as the solar wind presses against the gas and dust released from a comet to produce the tail which always points away from the Sun. 

A recent animation of Comet 12P. Image credit: Michael Jaeger.

As the comet travels around the Solar System, it deposits debris along its orbit almost like a trail of celestial breadcrumbs. The debris at this stage is known as meteoroids but, if the Earth travels through it then they create the stunning meteors that we see streak across the sky. The Earth passes through the debris field from a number of comets on a regular, annual basis and this gives rise to the regular meteor showers we see such as he Perseids or Leonids. 

A Geminid meteor outburst from 2020. Image credit and copyright: Jeff Sullivan

A team of 45 researchers have been studying meteor showers and have discovered something rather curious. They have found that not all comets crumble in the same way as they approach the Sun. The team studied 47 young meteor showers by using special low light video cameras all over the world. The cameras measured the path of the meteors enabling the team to work out how high up they were when they first light up and how they then slowed down in the atmosphere. They were also able to measure the composition enabling them to deduce the size of the particles.

In a paper published in the journal Icarus, the team theorised that a comet will simply crumble into the size of the ‘pebbles’ they are made of. This does seem to make complete sense given that the comets form as chunks of dust, rock and ice. More ice will slowly form as the comet orbits out in the dark cold reaches of the Solar System but as it heats on its journey inwards, it will just fall apart again as the ice sublimates. 

The results of the paper showed that longer period comets, such as those originating in the Oort Cloud generally crumble into sizes of particulates indicative of slow and gentle accretion conditions.  The resultant meteoroids have a lower density and tend to only brighten deeper into the Earth’s atmosphere. Comets from the Jupiter-family on the other hand crumble up into smaller, denser meteoroids with 8% more solid material on average.

There are a few meteor showers that originate from asteroids and these too have been studied. The team found that they tend to produce meteor showers with smaller particles that have evidence of aggressive fragmentation during their formation. The team acknowledge there will be exceptions to their findings but it their study has helped to build a more fuller picture of the early stages of the evolution of the Solar System and to the nature of comets that grant us the beauty of meteor showers.

Source : Meteor showers shed light on where comets formed in the early solar system

The post Explaining Different Kinds of Meteor Showers. It’s the Way the Comet Crumbles appeared first on Universe Today.

Google has built a quantum computer that makes fewer errors as it is scaled up, and this may pave the way for machines that could solve useful real-world problems for the first time

Meanwhile, in Dobrzyn, Hili has won at hide-and-seek:

A: I’ve been looking for you for the last hour.
Hili: You could’ve taken a look into the wardrobe an hour ago and you would have found me.

Ja: Od godziny cię szukam.
Hili: Mogłeś godzinę temu zajrzeć do szafy, od razu byś mnie znalazł.

In creating a pair of new robots, researchers cultivated an unlikely component, one found on the forest floor: fungal mycelia. By harnessing mycelia's innate electrical signals, the researchers discovered a new way of controlling 'biohybrid' robots that can potentially react to their environment better than their purely synthetic counterparts.

In creating a pair of new robots, researchers cultivated an unlikely component, one found on the forest floor: fungal mycelia. By harnessing mycelia's innate electrical signals, the researchers discovered a new way of controlling 'biohybrid' robots that can potentially react to their environment better than their purely synthetic counterparts.

The discovery of dark oxygen at an abyssal plain on the ocean floor generated a lot of interest. Could this oxygen source support life in the ocean depths? And if it can, what does that mean for places like Enceladus and Europa?

What does it mean for our notion of habitability?

Oxygen is key to complex life on Earth, where photosynthesis generates most of it. The Great Oxygenation Event (GOE), which occurred about 2.5 billion years ago, led to the development of complex life and changed Earth forever. In the GOE, the oxygen was generated by living things.

Our notions of habitability rest on a planet’s proximity to its star, and part of that is because we know that the Sun drives life on Earth by allowing water to remain liquid and providing energy for organisms. But dark oxygen on the ocean floor is strictly abiotic, meaning no life was involved in its production and sunlight isn’t involved.

In recent years, we’ve learned that other Solar System bodies, far beyond the circumstellar habitable zone, could be habitable. The icy ocean moons of Europa, Ganymede, and Enceladus may harbour vast, warm oceans under frigid caps of ice. If Earth produces dark oxygen on its ocean floors, maybe these worlds do, too.

New research examines Earth’s dark oxygen and what it might mean for biology here and on other worlds. It’s titled “Dwellers in the Deep: Biological Consequences of Dark Oxygen.” The lead author is Manasvi Lingam from the Department of Aerospace, Physics, and Space Sciences at the Florida Institute of Technology. The research is awaiting peer review.

Dark oxygen comes from metal deposits called polymetallic nodules. These nodules generate enough electricity to drive electrolysis, which splits water molecules apart and releases oxygen. The amount of oxygen is not large, but it’s there, and it’s measurable.

By Hannes Grobe/AWI – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=104756773

“The striking recent putative detection of “dark oxygen” (dark O2) sources on the abyssal ocean floor in the Pacific at ~4 km depth raises the intriguing scenario that complex (i.e., animal-like) life could exist in underwater environments sans oxygenic photosynthesis,” the authors write.

The amount of dark oxygen in the ocean is small, which limits the size of organisms. Organisms use oxygen through diffusion and circulation, and oxygen levels place restraints on the sizes of both types.

Diffusion is a simple process in which nutrients, waste, and water diffuse through a few layers of tissue. Circulation is more complex and involves a heart pumping fluid to an organism’s cells, delivering nutrients and removing waste. The amount of environmental oxygen places limits on the sizes of both types of organisms.

“The maximal sizes attainable by idealized unicellular or multicellular organisms (i.e., constrained by internal or external diffusion processes) for the estimated concentrations of dark O2 may be ~ 0.1–1 mm.,” the authors write.

For animals with circulation systems, the upper size boundary is higher but still limited.

“In contrast, the upper-size bounds of organisms with internal circulation systems for the distribution of oxygen could range between ~ 0.1 cm to ~ 10 cm, with the latter threshold falling under the umbrella of “megafauna,” the researchers explain.

Aside from the size of individual organisms, there’s the overall biomass density. In an optimistic scenario, the researchers report that biomass density could exceed the reported density. “Under optimistic circumstances, the biomass densities might reach as high as ~ 3–30 g m?2, in principle exceeding the reported macrofaunal densities at depths of ~ 4 km in global deep-sea surveys,” the authors write.

This work inspires a multitude of questions. We know that microorganisms in groundwater use dark oxygen. What types of microorganisms have adapted to these ocean dark oxygen environments? What about their metabolism allows them to live there? Have larger organisms adapted to these environments? Did organisms in these environments play a role in the evolution of life on Earth?

The discovery also compels us to consider its implications for astrobiology. On Earth, abyssal deep sea plains represent about 70% of the ocean floor, making them the largest ecosystem on Earth. Even with a low biomass density, the region is significant.

This cross-section of an oceanic basin shows the relationship of the abyssal plain to a continental rise and an oceanic trench. On Earth, 70% of the sea floor is abyssal plain, making it the largest ecosystem on Earth. Image Credit: By Chris_huh – Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=1812130

When considering the habitability of the ocean moons, we’re at a disadvantage. We don’t know what the sea floors look like on these bodies. In fact, despite all of the enthusiasm, we don’t even know for certain if these moons have oceans. We also don’t know if the oceans, if any of them exist, can produce polymetallic nodules that generate dark oxygen.

However, there are other ways dark oxygen can be generated without nodules. One of them is radiolysis.

Radiolysis is the breaking apart of molecules by ionizing radiation, and there’s plenty of that in the vicinity of Jupiter. Spacecraft have spotted O2 trapped in bubbles on Europa, Ganymede, and Callisto. Does that mean it’s available for life that might exist in their hypothetical oceans?

Radiation from Jupiter can break apart molecules on Europa’s surface. This can free oxygen, which could percolate in brines through the surface into the ocean under the ice. Credit: NASA/JPL-Caltech

“The production of oxidants on the surface and their delivery to the ocean can effectively input O2 to the latter even sans photosynthesis,” the authors explain. Europa’s icy shell isn’t all solid ice. Scientists think that briny liquid can percolate through the ice, and that could potentially deliver surface dark oxygen to the ocean.

There’s a third pathway for dark oxygen called microbial dismutation. Though it’s biotic, it doesn’t rely on photosynthesis. It could be an overlooked source of oxygen.

The evidence we have so far says that worlds like Earth are extremely rare, while environments like Europa could be widespread. “To round off our preliminary venture into this eclectic subject, we reiterate our
prefatory statement that marine habitable settings implausible for photosynthesis, especially on icy worlds with subsurface oceans, are likely widespread in the Universe,” the authors write in their conclusion.

“Therefore, if dark oxygen production is feasible and commonplace on this class of worlds – whether via seawater electrolysis or the prior two routes – then our analysis may broadly encapsulate the profound consequences of dark oxygen for the prevalence of abiogenesis, complex multicellularity, and perhaps even technological intelligence in the Cosmos,” the authors explain.

The fact that we’ve only now discovered dark oxygen on the ocean floor should make us all pause. We’re discovering things about nature that could be critical in the search for life and habitable worlds. If we can confirm that the so-called ocean moons really do have oceans and that dark oxygen is either produced in or transported to those oceans, then we have to adapt our thinking about habitability. Proximity to a star may not be critical, which would simultaneously broaden our understanding while deepening the mystery of life in the cosmos.

That’s the intriguing part of science. It’s equal part mysteries and answers.

The post Dark Oxygen Could Change Our Understanding of Habitability appeared first on Universe Today.

In simulated life-or-death decisions, about two-thirds of people in a study allowed a robot to change their minds when it disagreed with them -- an alarming display of excessive trust in artificial intelligence, researchers said.

Research shows that super spikes, scientifically described as advanced footwear technology (AFT) spikes, can give runners about a 2% edge in middle-distance track races, like the 800- and 1,500-meters.

The impact of embodied carbon in the built environment has been difficult to assess, due to a lack of data. To address that knowledge gap civil and environmental engineers have created a new tool to analyze the embodied carbon in more than 1 million buildings in Chicago. Their recently published research identifies 157 different architectural housing types in the city and provides the first ever visual analysis tool to evaluate embodied carbon at a granular level and to help inform policymakers seeking to strategically plan for urban carbon mitigation.

New research proposes a way to predict and prevent temperature spikes and fires in the lithium-ion batteries commonly used to power electric vehicles.

With all of humanity’s telescopic eyes on the sky, it’s rare for an asteroid to take us by surprise. But that’s what happened this morning in the sky over the Philippines. Only hours after it was detected, it burned up in a bright flash above the island of Luzon.

NASA’s Catalina Sky Survey detected the small asteroid, now named 2024 RW1, only hours before it reached Earth’s atmosphere. It was only about one meter in diameter and posed no threat. Even though reports say it “struck the Earth,” in reality, it only struck the atmosphere, where objects that small burn up.

A video captured from the northern tip of the Philippines shows a flashing fireball partly obscured by clouds. The asteroid briefly created a tail, which disappeared quickly.

??????? ?? ?????, ???????? ???? ???! ??

Here's a clear shot of the much-awaited small asteroid 2024 RW1 (#CAQTDL2) burning bright into a greenish 'fireball' over Lal-lo, Cagayan around 12:39 AM PhST, 05 September 2024. Did you see it too? ?

?… pic.twitter.com/B3oAm6nNdD

— ScienceKonek (@sciencekonek) September 4, 2024

This is only the ninth time that we’ve detected an asteroid before it reached Earth, though the European Space Agency says that a one-meter asteroid hits the Earth every two weeks.

Being taken by surprise by an asteroid is an unusual feeling. But though it was a surprise, it was detected before it reached us. We can take comfort that our automated sky surveys detected such a small object. If it was large enough to cause any amount of damage, it would’ve been brighter and we’d have detected it much sooner.

Though this one was no danger, that’s not always the case. In 2013, the 18-ton near-Earth asteroid called the Chelyabinsk meteor exploded over the Russian city. It created extensive ground damage and caused almost 1500 people to seek medical assistance, though nobody was killed.

A meteorite flashes across the sky over Chelyabinsk, Russia, taken from a dashboard camera.

Earth has suffered much more catastrophic impacts than that throughout its history, and that spectre haunts our civilization. The Chicxululb impact caused a mass extinction and ended the dinosaurs. The Vredefort Crater in South Africa was excavated two billion years ago by an impactor between 10 to 15 km in diameter.

But it’s not just an asteroid’s size that’s the problem. They strike Earth with great velocity. The ESA says that 2024 RW1 was travelling at 17.6 kilometres per second, or 63,360 kilometres per hour, which is the average speed for these objects.

Both NASA and the ESA actively search for and catalogue the asteroid population. NASA also invites experts to take part in regular mock exercises. In these exercises, teams of people are fed regular fabricated updates on the approach of a dangerous asteroid and asked to take whatever actions they see fit.

2024 RW1 was no threat. In fact, it’s a beautiful, natural spectacle.

But it’s also a reminder that Earth isn’t isolated from the cosmos, though in day-to-day life, it can seem like it is.

The post A Surprise Asteroid Lit Up the Sky Over the Philippines appeared first on Universe Today.

A band that measures the acidity of sweat could flag if athletes or manual workers are overexerting themselves

Electric vehicle charging stations bring spending increases for nearby businesses, according to a new study.

It's 7 billion years ago, and the universe's heyday of star formation is beginning to slow. What might our Milky Way galaxy have looked like at that time? Astronomers have found clues in the form of a cosmic question mark, the result of a rare alignment across light-years of space.

Between Low Earth Orbit (LEO) and the Moon, there is a region of space measuring 384,400 km (238,855 mi) wide known as Cislunar space. In the coming decades, multiple space agencies will send missions to this region to support the development of infrastructure that will lead to a permanent human presence on the Moon. This includes orbital and surface habitats, landing pads, surface vehicles, technologies for in-situ resource utilization (ISRU), and other elements that will enable the long-term exploration and development of the lunar surface.

For all parties concerned, Cislunar space holds immense potential in terms of scientific, commercial, and military applications. The vastly increased level of activity on and around the Moon makes space domain awareness (SDA) – knowledge of all operations within a region of space – paramount. It is also necessary to ensure the continued success and utilization of the covered region. In a recent paper, a team of aerospace engineers considered the missions planned for the coming decades and evaluated the state and shortcomings of their space domain awareness.

The study was led by Brian Baker-McEvilly, an aerospace engineering graduate student at Embry-Riddle Aeronautical University (ERAU). He was joined by David Canales, an assistant professor of aerospace engineering at ERAU, and Surabhi Bhadauria and Carolin Frueh, a Ph.D. candidate and an assistant professor at Purdue University’s School of Aeronautics and Astronautics. The paper that describes their findings recently appeared online and is being considered for publication by

NASA’s Lunar Surface Sustainability Concept, which includes the Artemis Program. Credit: NASA Space Domain Awareness

Also known as “space situational awareness,” SDA is essential to operations in space. As Baker-McEvilly explained to Universe Today via email:

“SDA is essentially the concept of having comprehensive knowledge of all objects in a specific region without necessarily having direct communication with those objects. It is essential for the safety and security of spacecraft as it provides valuable information on objects in their vicinity that have the potential to influence the outcome of their mission. Some general examples of the importance of SDA are the information helps avoid collisions, ensures accurate tracking information, and provides knowledge on other space activities.”

As NASA states, the goal of the Artemis Program is to “create a sustained program of lunar exploration and development.” Similarly, China, Roscosmos, and the ESA hope to create lunar habitats and related infrastructure to allow for a permanent human presence on the Moon. A key element of these programs is to create habitats in the Moon’s southern polar region (the South Pole-Aitken Basin). These activities will require considerable support in the form of payload deliveries, and the export of lunar resources will similarly require regular missions to and from the lunar surface. Given this level of activity, SDA will be more vital than ever.

Many Plans

As per the Artemis Program, NASA intends to conduct the first circumlunar flight with a crewed Orion spacecraft (Artemis II) no sooner than September 2025. This will be followed by Artemis III in September 2026, the first crewed mission to the lunar surface since Apollo 17 in 1972. This will be accomplished by launching a crewed Orion spacecraft using the Space Launch System (SLS) to lunar orbit. The Human Landing System (HLS) provided by SpaceX – the Starship HLS – will launch separately, refuel in orbit, and then rendezvous with the Orion spacecraft around the Moon.

Once the transfer of two astronauts to the HLS is complete, they will fly down to the lunar surface and spend about 30 days conducting experiments and retrieving samples. Beyond Artemis III, NASA will begin to focus on deploying the core elements of the Lunar Gateway, which will launch in 2027 aboard a Falcon Heavy rocket. The Artemis IV mission will follow in September 2028 and will see a crew of four transfer from an Orion spacecraft to the Lunar Gateway for the first time. After that, NASA intends to send a mission a year to the lunar surface and deploy the elements of the Artemis Base Camp. These will include the following:

• Lunar Terrain Vehicle (LTV): a rover that will transport crew around the landing zone
• Habitability Mobility Platform (HMP): a pressurized rover that will enable crews to take trips across the lunar surface lasting up to 45 days
• Lunar Foundation Surface Habitat (LFSH): a stationary habitat that will house as many as four crew members on shorter surface stays

Credit: NASA

In addition, China and Russia have announced their intentions to create the International Lunar Research Station (ILRS), which would rival NASA’s proposed infrastructure. The proposed timeline involves three phases. The Reconnaissance phase will conclude with the Chang’e-7 mission (launching in 2026), which will continue to explore the lunar surface around the South Pole-Aitken Basin to scout for resources and assess possible sites for a future habitat. Phase Two, Construction, will occur between 2026 and 2035 and will see the deployment of the elements that make up the ILRS.

Meanwhile, the European Space Agency (ESA) has made multiple studies and proposals for an international lunar base that would serve the same purpose as the International Space Station (ISS). Previous proposals include the ESA’s Moon Village, which consisted of a facility extending beneath the surface and a dome covered in regolith that would allow access to the surface. This was followed in 2019 with the ESA and international architecture firm Skidmore, Owings & Merrill (SOM) proposing a series of semi-inflatable modules deployed along the rim of a lunar crater.

The latest concept was another collaborative effort between the ESA and the international architecture firm Hassel. Their proposal, the Lunar Habitat Master Plan, consists of a modular, scalable habitat system that can accommodate a settlement of up to 144 people. As part of their study, Baker-McEvilly and his colleagues reviewed these plans and identified two major trends. As he related.

“Two key trends emerge when looking over these missions; the importance of establishing sustainable operations and the strategic value of the Lunar South Pole. Many future missions have objectives to test new technologies that support sustainable operations on the Moon, such as water harvesting methods from Lunar regolith for astronauts, efficient landing methods to support constant movement to and from the surface of the Moon, or utilizing orbital trajectories that require little fuel to remain within.

“The Lunar South Pole is a key piece of Cislunar space as it is an efficient geographic location for these sustainable operations. The South Pole possesses permanently shadowed craters that contain concentrations of water within the regolith. Also, the near-rectilinear halo orbit (NRHO) that will house Gateway spends the majority of its trajectory within line of sight of the South Pole and requires very little fuel to maintain under outside perturbations.”

Getting There

Another key aspect of their study was the dynamics of the Cislunar environment and the challenges of sending spacecraft from the Earth to the Moon. These challenges are well-known, thanks to decades of sending robotic missions there, not to mention crewed missions in the form of the Apollo Program. In the coming decades, this region is expected to become rather crowded with satellites, spacecraft, the Lunar Gateway, and other orbital facilities. Things are made more complicated by the fact that any object in Cislunar space will have to contend with the Three-Body Problem. Said Baker-McEvilly:

“[The] dynamics of the Cislunar realm become challenging due to the introduction of the third body in the orbital mechanics problem. As of now, the three-body problem does not have a closed-form solution, and a spacecraft under the influence of both the Earth and Moon no longer moves in the traditional two-body Keplerian sense that many are familiar with. This causes many of the traditional methods in astrodynamics to break down, thus requiring new models and methods to solve problems.”

In the end, they identified a few families of orbits that highlight the unique geometry of periodic trajectories in the Three-Body Problem, as well as orbits that may have strategic use in the future. However, as Baker-McEvilly added, these trajectories are not all-encompassing, and many more exist that have been well-documented.

Shortcomings

Upon reviewing the existing and anticipated missions that will be going to the Moon in the coming decades, Baker-McEvilly and his colleagues identified several shortcomings where SDA was concerned. They also provide recommendations on how these can be addressed. As he indicated:

“The SDA methods used to monitor objects about the Earth that rely on Earth-based sensors do not directly translate to being able to view objects in Cislunar space. The significant distance an Earth-based sensor must cover to reach areas of Cislunar space is outside the capabilities of many sensors, especially radar systems. For the sensors capable of spanning this distance, such as the Deep Space Network, they are often already overtasked and are too valuable to only be dedicated to SDA.

“Another shortcoming is the challenging illumination conditions optical sensors must overcome to view objects deep in Cislunar space. Issues such as the Moon physically blocking view of missions on the far-side, or the light reflected off the Moon washing out light reflected off a spacecraft hinders the capabilities of optical sensors. As a result, there are important regions of Cislunar space that are not always in view by current sensor networks.”

Artist’s representation of Cislunar space, with distances included. Credit: Paul Spudis.

As Baker-McEvilly noted, researchers are investigating many approaches to address the gap in Cislunar SDA capabilities. Some possibilities include placing sensors on the Moon, improving the network of Earth-based sensors, or implementing constellations of satellite-based sensors throughout Cislunar space. In his opinion, some combination of these solutions is best suited to solving the SDA gap. He also hopes their study provides researchers, students, and those interested in lunar exploration with a foundation on the current state of Cislunar space and the issues it faces.

“The key issues highlighted across the analysis in Cislunar exploration and SDA may incline some readers to pay more attention to these points and come up with their own work that contributes to the solution or prevent similar failures from repeating themselves,” he said.

Further Reading: arXiv

The post A Review of Humanity’s Planned Expansion Between the Earth and the Moon appeared first on Universe Today.

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