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Science

NASA and DARPA to develop nuclear thermal rocket engine that may put humans on Mars: reports

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NASA is partnering with the Defense Advanced Research Projects Agency, or DARPA, to use a nuclear thermal rocket engine in space, according to reports.

In a press release on Tuesday, NASA said the nuclear thermal rocket engine could one day be used for NASA crewed missions to Mars.

Artist concept of Demonstration for Rocket to Agile Cislunar Operations (DRACO) spacecraft, which will demonstrate a nuclear thermal rocket engine. Nuclear thermal propulsion technology could be used for future NASA crewed missions to Mars.
(DARPA and NASA)

Both agencies will collaborate on the Demonstration Rocket for Agile Cislunar Operations, or DRACO, program, under a “non-reimbursable agreement.”

NASA’S ARTEMIS I LAUNCH TO BRING US STEP CLOSER TO ‘SUSTAINABLE HUMAN FOOTPRINT ON THE MOON’

The agreement, the release read, is designed to benefit both agencies while outlining roles, responsibilities and processes that could accelerate the program’s development.

“NASA will work with our long-term partner, DARPA, to develop and demonstrate advanced nuclear thermal propulsion technology as soon as 2027,” NASA Administrator Bill Nelson said. “With the help of this new technology, astronauts could journey to and from deep space faster than ever – a major capability to prepare for crewed missions to Mars. Congratulations to both NASA and DARPA on this exciting investment, as we ignite the future, together.”

The nuclear thermal rocket would allow transit between the moon and Mars to take less time while also reducing the risk for astronauts.

NASA  Administrator Bill Nelson speaks during a visit to the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center on November 5, 2021 in Greenbelt, Maryland. 
((Photo by OLIVIER DOULIERY/AFP via Getty Images))

Longer trips require more supplies, so reducing the transit time would be a key component for human missions to Mars. 

NASA INSIGHT LANDER RECORDS LARGEST QUAKE ON MARS EVER, SCIENTISTS SAY

Additional benefits include increased science payload capacity and higher power generation for instruments and communications.

Nuclear thermal rocket engines have a fission reactor that generates extremely high temperatures. NASA said the engine transfers that heat to a liquid propellant which is exhausted through a nozzle that propels the spacecraft.

These types of engines, NASA added, can be three times more efficient than chemical propulsion engines.

NASA’s Perseverance Mars rover used its dual-camera Mastcam-Z imager to capture this image of “Santa Cruz,” a hill within Jezero Crater, on April 29, 2021, the 68th Martian day, or sol, of the mission. 
(Credits: NASA/JPL-Caltech/ASU/MSSS)

“NASA has a long history of collaborating with DARPA on projects that enable our respective missions, such as in-space servicing,” NASA Deputy Administrator Pam Melroy said. “Expanding our partnership to nuclear propulsion will help drive forward NASA’s goal to send humans to Mars.”

NASA’S MARS LANDER INSIGHT TRANSMITS POTENTIAL FINAL IMAGE OF THE RED PLANET AS ITS POWER DWINDLES

As part of the agreement, NASA will lead the technical development of the nuclear thermal engine while DARP will function as the contracting authority for the stage and engine, including the reactor.

DARPA will also lead the overall program, including rocket system integration, procurement, approvals, security, scheduling, and more.

The goal is to be able to demonstrate the rocket in space as early as 2027.

“DARPA and NASA have a long history of fruitful collaboration in advancing technologies for our respective goals, from the Saturn V rocket that took humans to the Moon for the first time to robotic servicing and refueling of satellites,” Dr. Stefanie Tompkins, director, DARPA said. “The space domain is critical to modern commerce, scientific discovery, and national security. The ability to accomplish leap-ahead advances in space technology through the DRACO nuclear thermal rocket program will be essential for more efficiently and quickly transporting material to the Moon and eventually, people to Mars.”

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NASA said the last nuclear thermal rocket engine tests conducted by the U.S. took place more than 50 years ago under NASA’s Nuclear Engine for Rocket Vehicle Application and Rover projects.

Greg Wehner is a breaking news reporter for Fox News Digital.

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Science

How the last 12,000 years have shaped what humans are today

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Credit: Pixabay/CC0 Public Domain

While humans have been evolving for millions of years, the past 12,000 years have been among the most dynamic and impactful for the way we live today, according to an anthropologist who organized a special journal feature on the topic in the Proceedings of the National Academy of Sciences.

Our modern world all started with the advent of agriculture, said Clark Spencer Larsen, professor of anthropology at The Ohio State University.

“The shift from foraging to farming changed everything,” Larsen said.

Along with food crops, humans also planted the seeds for many of the most vexing problems of modern society.

“Although the changes brought about by agriculture brought plenty of good for us, it also led to increasing conflict and violence, rising levels of infectious diseases, reduced physical activity, a more limited diet, and more competition for resources,” he said.

Larsen is organizer and editor of a Special Feature published in the Jan. 17, 2023, issue of the journal Proceedings of the National Academy of Sciences. He is also author of the introduction to the section, titled “The past 12,000 years of behavior, adaptation, population, and evolution shaped who we are today.”

The Special Feature includes eight articles based mostly on bioarchaeology—the study of human remains and what they can tell scientists about changes in diet, behavior and lifestyle over the last 10 millennia or so. Larsen is co-author on two of these eight articles.

One message that connects all the articles is that the major societal issues of today have ancient roots, he said.

“We didn’t get to where we are now by happenstance. The problems we have today with warfare, inequality, disease and poor diets, all resulted from the changes that occurred when agriculture started,” Larsen said.

The shift from foraging to farming led humans, who had led a mostly transitory life, to create settlements and live a much more sedentary existence.

“That has had profound implications for virtually every aspect of our lives back then, now, and going forward,” he said.

Growing food allowed the world population to grow from about 10 million in the later Pleistocene Epoch to more than 8 billion people today.

But it came at a cost. The varied diet of foragers was replaced with a much more limited diet of domesticated plants and animals, which often had reduced nutritional quality. Now, much of the world’s population relies on three foods—rice, wheat and corn—especially in areas that have limited access to animal sources of protein, Larsen said.

Another important change in the diet of humans was the addition of dairy. In one article in the Special Feature, researchers examined dental calculus found in remains to show the earliest evidence of milk consumption dates to about 5,000 years ago in northern Europe.

“This is evidence of humans adapting genetically to be able to consume cheese and milk, and it happened very recently in human evolution,” he said. “It shows how humans are adapting biologically to our new lifestyle.”

As people began creating agricultural communities, social changes were occurring as well. Larsen co-authored one article that analyzed strontium and oxygen isotopes from tooth enamel of early farming communities from more than 7,000 years ago to help determine where residents were from. Results showed that Çatalhöyük, in modern Turkey, was the only one of several communities studied where nonlocals apparently lived.

“This was laying the foundation for kinship and community organization in later societies of western Asia,” he said.

These early communities also faced the problem of many people living in relatively cramped areas, leading to conflict.

In one article, researchers studying human remains in early farming communities across western and central Europe found that about 10% died from traumatic injuries.

“Their analysis reveals that violence in Neolithic Europe was endemic and scaling upward, resulting in patterns of warfare leading to increasing numbers of deaths,” Larsen writes in the introduction.

Research reported in this PNAS issue also reveals how these first human communities created the ideal conditions for another problem that is top-of-mind in the world today: infectious disease. Raising farm animals led to the common zoonotic diseases that can be transmitted from animals to people, Larsen said.

While the climate change crisis of today is unique in human history, past societies have had to deal with more short-term climate disasters, particularly long droughts.

In a perspective article co-authored by Larsen, the researchers noted that economic inequality, racism and other types of discrimination have been key factors in how societies have fared under these climate emergencies, and these factors will play a role in our current crisis.

Those communities with more inequality were most likely to experience violence in the wake of climate disasters, Larsen said.

What may be most surprising about all the changes documented in the Special Feature is how quickly they all occurred, he said.

“When you look at the six or so million years of human evolution, this transition from foraging to farming and all the impact it has had on us—it all happened in just a blink of an eye,” Larsen said.

“In the scale of a human lifespan it may seem like a long time, but it really is not.”

The research presented in the Special Feature also shows the amazing ability of humans to adjust to their surroundings.

“We are remarkably resilient creatures, as the last 12,000 years have shown,” he said.

“That gives me hope for the future. We will continue to adapt, to find ways to face challenges and to find ways to succeed. That is what we do as humans.”

More information:
Larsen, Clark Spencer, The past 12,000 years of behavior, adaptation, population, and evolution shaped who we are today, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2209613120. doi.org/10.1073/pnas.2209613120

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How the last 12,000 years have shaped what humans are today (2023, January 16)
retrieved 17 January 2023
from https://phys.org/news/2023-01-years-humans-today.html

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Science

Most humans haven’t evolved to cope with the cold, yet we dominate northern climates—here’s why

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Many humans dread the cold of winter. Credit: Mariia Boiko/Shutterstock

Humans are a tropical species. We have lived in warm climates for most of our evolutionary history, which might explain why so many of us spend winter huddled under a blanket, clutching a hot water bottle and dreaming of summer.

Indeed all living apes are found in the tropics. The oldest known fossils from the human lineage (hominins) come from central and eastern Africa. The hominins who dispersed northwards into higher latitudes had to deal with, for the first time, freezing temperatures, shorter days that limited foraging time, snow that made hunting more difficult and icy wind chill that exacerbated heat loss from their bodies.

Given our limited adaptation to the cold, why is it that our species has come to dominate not only our warm ancestral lands but every part of the globe? The answer lies in our ability to developed intricate cultural solutions to the challenges of life.

The earliest signs of hominins living in northern Europe are from Happisburgh in Norfolk, eastern England, where 900,000-year-old footprints and stone tools have been found. At that time, Happisburgh was dominated by coniferous forest with cold winters, similar to southern Scandinavia today. There is little evidence the Happisburgh hominins stayed at the site for long, which suggests they didn’t have time to adapt physically.

It’s still a bit of a mystery how these hominins survived the tough conditions that were so different from their ancestral African homelands. There are no caves in the region, nor evidence of shelters. Artifacts from Happisburgh are simple, suggesting no complex technology.

Evidence for deliberate campfires at this time is contentious. Tools for tailoring fitted, weather-proof clothes don’t appear in western Europe until almost 850,000 years later. Many animals migrate to avoid seasonal cold, but the Happisburgh hominins would have had to travel about 800km south to make a meaningful difference.

It’s hard to imagine hominins surviving those ancient Norfolk winters without fire or warm clothing. Yet the fact the hominins were so far north means they must have found a way to survive the cold, so who knows what archaeologists will find in the future.

The Boxgrove hunters

Sites from more recent settlements, such as Boxgrove in West Sussex, southern England, offer more clues about how ancient hominins survived northern climates. The Boxgrove site dates to nearly 500,000 years ago, when the climate deteriorated towards one of the coldest periods in human history.

There is good evidence these hominins hunted animals, from cut marks on bones, to a horse shoulder blade probably pierced by a wooden spear. These finds fit with studies of people who live as foragers today which show people in colder regions depend on animal prey more than their warm climate counterparts. Meat is rich in the calories and fats needed to weather the cold.

A fossilized hominin shin bone from Boxgrove is robust compared to living humans, suggesting it belonged to a tall, stocky hominin. Larger bodies with relatively short limbs reduce heat loss by minimizing surface area.

The best silhouette for avoiding heat loss is a sphere, so animals and humans in cold climates get as close to that shape as possible. There is also clearer evidence for campfires by this period.

Cold climate specialists

The Neanderthals, who lived in Eurasia about 400,000-40,000 years ago, inhabited glacial climates . Compared to their predecessors in Africa, and to us, they had short, strong limbs, and wide, muscular bodies suited to producing and retaining heat.

Yet the Neanderthal protruding face and beaky nose are the opposite of what we might expect to be adaptive in an ice age. Like Japanese macaques living in cold areas and lab rats raised in cold conditions, living humans from cold climates tend to have relatively high, narrow noses and broad, flat cheekbones.

Computer modeling of ancient skeletons suggests Neanderthal noses were more efficient than those of earlier, warm-adapted species at conserving heat and moisture. It seems the internal structure is as important as overall nose size.

Even with their cold-adapted physique, Neanderthals were still hostage to their tropical ancestry. For example, they lacked the thick fur of other mammals in glacial Europe, such as wooly rhinos and musk oxen. Instead, Neanderthals developed complex culture to cope.

There is archaeological evidence they made clothes and shelters from animal skins. Evidence of cooking and use of fire to make birch pitch glue for the manufacture of tools show sophisticated Neanderthal control of fire.

More controversially, some archaeologists say early Neanderthal bones from the 400,000-year-old site of Sima de los Huesos in northern Spain show seasonal damage from slowing down their metabolisms to hibernate. The authors argue these bones show cycles of interrupted growth and healing.

Only a few species of primate hibernate such as some lemurs in Madagascar and the African lesser bushbaby, as well as the pygmy slow loris in norther Vietnam.

This might give you the idea that humans can hibernate too. But most species that hibernate have small bodies, with some exceptions like bears. Humans may be too big to hibernate.

Jack of all trades

The earliest fossils in the Homo sapiens lineage date from 300,000 years ago, from Morocco. But we didn’t spread out of Africa until about 60,000 years ago, colonizing all parts of the globe. This makes us relative newcomers in most habitats we now inhabit. Over the intervening thousands of years, people living in freezing cold places have adapted biologically to their environment but on a small scale.

One well-known example of this adaptation is that in areas with low sunlight, Homo sapiens developed light skin tones, which are better at synthesizing vitamin D. The genomes of living Inuit people from Greenland demonstrate physiological adaptation to a fat-rich marine diet, beneficial in the cold.

More direct evidence comes from DNA from a single 4,000-year-old permafrost-preserved hair from Greenland. The hair hints at genetic changes that led to stocky body shape that maximized heat production and retention, like the hominin we only have one shin bone from the Boxgrove site.

Our tropical legacy means we would still be unable to live in cold places without developing ways of coping with the temperatures. Take, for example, the traditional Inuit parka, which provides better insulation than the modern Canadian army winter uniform.

This human ability to adapt behaviorally was crucial to our evolutionary success. Even compared to other primates, humans show less physical climatic adaptation. Behavioral adaptation is quicker and more flexible than biological adaptation. Humans are the ultimate adapters, thriving in nearly every possible ecological niche.

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Most humans haven’t evolved to cope with the cold, yet we dominate northern climates—here’s why (2023, January 16)
retrieved 16 January 2023
from https://phys.org/news/2023-01-humans-havent-evolved-cope-cold.html

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Health

Robot scans that can spot bowel cancer humans miss

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Robot scans that can spot bowel cancer humans miss: Scientists hope integrating AI technology into existing colonoscopy equipment could help save more lives

By Adrian Monti for the Daily Mail

Published: | Updated:

Artificial intelligence may be more effective than the human eye alone at spotting the early signs of bowel cancer.

A new UK trial is investigating whether adding AI technology — which uses computer algorithms to scan and read images — to standard colonoscopy examinations improves the accuracy of these scans.

More than 42,000 people are diagnosed with bowel cancer in the UK each year and 16,000 die from it, making it the second most common cause of cancer death.

Colonoscopies are the ‘gold standard’ way of diagnosing the disease. This is where the large bowel is examined using a camera attached to a thin, flexible tube.

Artificial intelligence may be more effective than the human eye alone at spotting the early signs of bowel cancer

The camera relays live images from inside the bowel on to a screen, allowing the clinician carrying out the procedure to check for pre-cancerous polyps called adenomas — small growths that can be found on the wall of the bowel. It is believed that bowel cancer develops from these polyps and, if detected, they can be removed during the procedure.

However, although colonoscopies are extremely effective, three in every 100 examinations miss a cancer or polyp which might be small, flat or hidden in the folds of the bowel but which goes on to become a cancer, according to the NHS.

Scientists hope that integrating AI technology (which not only reads scans but also learns as it goes along) into existing colonoscopy equipment could help save more lives by boosting the accuracy of the 45-minute procedure, so that more cancers are caught at an early stage when they’re easier to treat.

To try to locate these hard-to-find abnormalities, U.S. researchers have developed an AI box called the GI Genius which connects to colonoscopy equipment and analyses the video footage in real time.

Colonoscopies are the ‘gold standard’ way of diagnosing the disease. This is where the large bowel is examined using a camera attached to a thin, flexible tube [File photo]

If it spots something unusual, the device creates a green box on the screen pinpointing a precise section of the bowel lining which needs closer inspection and sounds an alert. The medic carrying out the scan will then decide whether to investigate further.

The first UK trial to test the AI device is halfway through screening around 2,000 NHS patients.

Patients enrolled on the trial have either undergone a colonoscopy before or have experienced symptoms such as blood in their stools or significant changes to their bowel habits, which they have reported to their GP; or have taken part in the NHS Bowel Screening Programme (a home testing kit sent to adults aged 60 to 74 in England, and from the age of 50 in Scotland).

Half of those on the trial will undergo a standard colonoscopy, the other half with the AI device.

Nine hospitals across England are taking part in the Colo-Detect trial, mostly in the North East, with the study being led by Newcastle University and South Tyneside and Sunderland NHS Foundation Trust.

The trial, funded by U.S. medical device company Medtronic that designed the device, is due to end in April (researchers will evaluate both the clinical and cost-effectiveness of the technology).

Results of the first U.S. trial of the device, published in the American Journal Gastroenterology last year, showed a 50 per cent reduction in missed polyps when the AI technology was used compared to standard colonoscopy.

Commenting on the new trial, Dr Duncan Gilbert, a consultant clinical oncologist in lower gastrointestinal cancers at University Hospitals Sussex NHS Foundation Trust, said: ‘Colorectal cancer remains a major public health challenge for the UK. Worryingly, it is also becoming more common in younger patients.

‘Screening using colonoscopy to find and remove polyps and early cancers has been shown to save lives and anything that improves the effectiveness of colonoscopy is to be welcomed.

‘Testing new technologies in properly conducted clinical trials such as this is exactly what we need to do and is an example of how NHS clinical research leads the world.’

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Science

Ancient humans had same sense of smell, but different sensitivities

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Credit: C0 Public Domain

If you had the grooming habits of a Neanderthal, perhaps it’s a good thing your nose wasn’t as sensitive to urine and sweat as a modern human’s.

And if you lived the hunting and gathering lifestyle of a Denisovan on the Asian steppes, your strong nose for energy-rich honey was almost certainly an advantage.

Though we can’t really know what these two extinct human species perceived or preferred to eat, a new study from Duke University scientists has figured out a bit more about what they might have been able to smell.

Using a technique they developed that allows researchers to test smell sensitivity on odor receptors grown in a lab dish, researchers Claire de March of CNRS Paris Saclay University and Hiroaki Matsunami of Duke University were able to compare the scents-abilities of three kinds of humans. Their work appeared Dec. 28 in the open access journal iScience.

Drawing from published databases of genomes, including ancient DNA collections amassed by 2022 Nobel Prize winner Svante Pääbo, the researchers were able to characterize the receptors of each of the three human species by looking at the relevant genes.

“It is very difficult to predict a behavior just from the genomic sequence,” said de March, who performed this work as a postdoctoral research associate at Duke. “We had the odorant receptor genomes from Neanderthal and Denisovan individuals and we could compare them with today’s humans and determine if they resulted in a different protein.”

So then they tested the responses of 30 lab-grown olfactory receptors from each hominin against a battery of smells to measure how sensitive each kind of receptor was to a particular fragrance.

The laboratory tests showed the modern and ancient human receptors were essentially detecting the same odors, but their sensitivities differed.

The Denisovans, who lived 30,000 to 50,000 years ago, were shown to be less sensitive to the odors that present-day humans perceive as floral, but four times better at sensing sulfur and three times better at balsamic. And they were very attuned to honey.

“We don’t know what Denisovans ate, but there some reasons why this receptor has to be sensitive,” said Matsunami, who is a professor of molecular genetics and microbiology in the Duke School of Medicine. Contemporary hunter-gatherers such as the Hadza of Tanzania are famous for their love of honey, an essential high-calorie fuel.

Neanderthals, who were still around up to 40,000 years ago and who apparently swapped a few genes with modern humans, were three times less responsive to green, floral and spicy scents, using pretty much the same receptors we have today. “They may exhibit different sensitivity, but the selectivity remains the same,” Matsunami said.

“The Neanderthal odorant receptors are mostly the same as contemporary humans, and the few that were different were no more responsive,” de March added.

Odor receptors have been linked to ecological and dietary needs in many species and presumably evolve as a species changes ranges and diets.

“Each species must evolve olfactory receptors to maximize their fitness for finding food,” Matsunami said. “In humans, it’s more complicated because we eat a lot of things. We’re not really specialized.”

The lab has also used their cell-based scent tester for seeing genetic variation among modern humans. “Some people can smell certain chemicals, but others can’t,” Matsunami said. “That can be explained by functional changes.”

More information:
Claire A. de March et al, Genetic and functional odorant receptor variation in the Homo lineage, iScience (2022). DOI: 10.1016/j.isci.2022.105908

Provided by
Duke University

Citation:
Ancient humans had same sense of smell, but different sensitivities (2023, January 5)
retrieved 6 January 2023
from https://phys.org/news/2023-01-ancient-humans-sensitivities.html

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part may be reproduced without the written permission. The content is provided for information purposes only.



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Science

Could humans use black holes to time travel?

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Black holes form natural time machines that allow travel to both the past and the future. But don’t expect to be heading back to visit the dinosaurs any time soon.

At present, we don’t have spacecraft that could get us anywhere near a black hole. But, even leaving that small detail aside, attempting to travel into the past using a black hole might be the last thing you ever do.

What are black holes?

A black hole is an extremely massive object that is typically formed when a dying star collapses in on itself.

Like planets and stars, black holes have gravitational fields around them. A gravitational field is what keeps us stuck to Earth, and what keeps Earth revolving around the Sun.

As a rule of thumb, the more massive an object is, the stronger its gravitational field.

Earth’s gravitational field makes it extremely difficult to get to space. That’s why we build rockets: we have to travel very fast to break out of Earth’s gravity.

Read more: How gravitational waves can ‘see inside’ black holes

The gravitational field of a black hole is so strong that even light can’t escape it. That’s impressive, since light is the fastest thing known to science!

Incidentally, that’s why black holes are black: we can’t bounce light off a black hole the way we might bounce a flashlight’s beam off a tree in the dark.

Stretching space

Albert Einstein’s general theory of relativity tells us matter and energy have a curious effect on the universe. Matter and energy bend and stretch space. The more massive an object is, the more space is stretched and bent around it.

A massive object creates a kind of valley in space. When objects come near, they fall into the valley.

3D illustration of the Earth and Sun on distorted spacetime. (Image credit: vchal via Shutterstock)

That’s why, when you get close enough to any massive object, including a black hole, you fall towards it. It’s also why light can’t escape a black hole: the sides of the valley are so steep that light isn’t going fast enough to climb out.

The valley created by a black hole gets steeper and steeper as you approach it from a distance. The point at which it gets so steep that light can’t escape is called the event horizon.

Event horizons aren’t just interesting for would-be time travellers: they’re also interesting for philosophers, because they have implications for how we understand the nature of time.

Stretching time

When space is stretched, so is time. A clock that is near a massive object will tick slower than one that is near a much less massive object.

A clock near a black hole will tick very slowly compared to one on Earth. One year near a black hole could mean 80 years on Earth, as you may have seen illustrated in the movie Interstellar.

In this way, black holes can be used to travel to the future. If you want to jump into the future of Earth, simply fly near a black hole and then return to Earth.

If you get close enough to the centre of the black hole, your clock will tick slower, but you should still be able to escape so long as you don’t cross the event horizon.

Loops in time

What about the past? This is where things get truly interesting. A black hole bends time so much that it can wrap back on itself.

Imagine taking a sheet of paper and joining the two ends to form a loop. That’s what a black hole seems to do to time.

This creates a natural time machine. If you could somehow get onto the loop, which physicists call a closed timelike curve, you would find yourself on a trajectory through space that starts in the future and ends in the past.

Inside the loop, you would also find that cause and effect get hard to untangle. Things that are in the past cause things to happen in the future, which in turn cause things to happen in the past!

The catch

So, you’ve found a black hole and you want to use your trusty spaceship to go back and visit the dinosaurs. Good luck.

There are three problems. First, you can only travel into the black hole’s past. That means that if the black hole was created after the dinosaurs died out, then you won’t be able to go back far enough.

Second, you’d probably have to cross the event horizon to get into the loop. This means that to get out of the loop at a particular time in the past, you’d need to exit the event horizon. That means travelling faster than light, which we’re pretty sure is impossible.

Third, and probably worst of all, you and your ship would undergo “spaghettification.” Sounds delicious, right?

Sadly, it’s not. As you crossed the event horizon you would be stretched flat, like a noodle. In fact, you’d probably be stretched so thin that you’d just be a string of atoms spiralling into the void.

So, while it’s fun to think about the time-warping properties of black holes, for the foreseeable future that visit to the dinosaurs will have to stay in the realm of fantasy.

This article is republished from The Conversation (opens in new tab) under a Creative Commons license. Read the original article (opens in new tab).

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Science

There’s no GPS on the moon. NASA and ESA have to fix that before humans return in 2 years.

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An artist’s impression of mining activities in a moon base.ESA – P. Carril

  • Dozens of moon missions are planned within the next decade.

  • But right now, there is no satellite navigation system between the Earth and the moon.

  • NASA and ESA are developing ways to help rockets navigate to the moon autonomously.

When NASA’s Artemis 1 mission successfully flew around the moon in November, it showed the world that humans are on track to go back.

NASA and the European Space Agency aim to put boots on the moon by 2025 and set up a permanent lunar base orbiting it within the next couple of years. China and Russia are also working together to establish a separate lunar base, with crewed landings set for 2036.

But right now, there is no GPS to get us there. Astronauts can’t navigate autonomously in deep space, and every mission relies on expertly trained engineers constantly directing the missions from the ground.

That will quickly become unsustainable with missions shuttling back and forth.

Space agencies are working to put satellite navigation, or satnav, on rockets traveling the 239,000 miles between Earth and the moon. They’re also planning to build a whole new navigation network around the moon. Here’s how.

How space agencies navigate today is cumbersome and expensive

It took hundreds of people to help Apollo mission rockets navigate to the moon. Here Apollo 11 staff are watching it lift off on July 16, 1969.NASA

Today, the only way to go from point A to point B in space is to make complicated calculations based on physics, custom to every mission.

As the spacecraft moves through space, the only point of reference is the Earth. So it needs to ping a signal back to the Earth to understand where it is, which means there are massive blind spots.

NASA completely lost communication with Orion, the spacecraft used in the Artemis 1 mission, when it went behind the moon. For a few minutes, all the engineers could do was hold their breath and hope they’d see the spacecraft emerge unscathed on the other side.

This is resource-intensive and expensive, Javier Ventura-Traveset, chief engineer of ESA’s Galileo Navigation Science Office, told Insider. (The US government runs GPS; Galileo is the European version.)

What space exploration needs now is a way for spacecraft to triangulate their position from space, so they can navigate autonomously without input from the Earth.

Using Earth’s satellites to go to the moon could help

Surprisingly, the cheapest way to bring satnav to deep space is to harness the satellites around the Earth, Elizabeth Rooney, a senior engineer for Surrey Satellite Technology Ltd, told Insider. The company is working with ESA to develop satellite navigation in space.

There are a few big problems with this approach. Chief among them is that these satellites point toward the Earth.

That means that most of the satellites’ signal is blocked and only a little spills over. The bit that spills over is a lot weaker than the main signal, and it gets even weaker further away from Earth.

Beyond the Earth’s immediate perimeter, called here the space service volume, the earth blocks a lot of the signal coming from earth’s navigation satellites (here called GNSS satellites, for Global Navigation Satellite System).NASA

Given all these constraints, it could seem like using this signal to navigate to the moon would be impossible. But engineers have spent decades developing sensitive detectors that could harness that signal from deep space.

And they succeeded.

In 2019, four satellites were able to determine their position in space using signals from the Earth’s GPS satellites.

They were 116,300 miles away — about halfway to the moon, Ventura-Traveset said.

We really need a way to go all the way to the moon autonomously

The next frontier is detecting that signal on the other half of the journey. But Ventura-Traveset is confident.

ESA and NASA have been refining their detectors that could harness signals from the Earth’s satellites, and are poised to test them on upcoming moon missions.

As part of ESA’s initiative, a detector will be mounted on a satellite orbiting the moon, called Lunar Pathfinder, to see if it can navigate autonomously.ESA-K Oldenburg/Insider

ESA’s receiver, called NaviMoon, is due to launch onboard the Lunar Pathfinder satellite in 2025 or 2026. ESA predicts NaviMoon should be able to determine the satellite’s position with a precision of about 60 meters (about 200 feet), Ventura-Traveset said.

The hope is that thanks to this detector, the satellite should be able to navigate autonomously around the moon, he said. It’s also very lightweight, about 4 kilograms (8 pounds) altogether, and could replace a lot of the heavier equipment onboard a spacecraft.

The NaviMoon satnav receiver being tested.SSTL

NASA is also working on detectors, developed with the Italian Space Agency. They aim to launch the first of these receptors to the surface of the moon in 2024 as part of the Lunar GNSS Receiver Experiment.

There is a “little bit of a friendly competitive race” between ESA and NASA to bring Earth satnav signal to the moon, James Joseph “JJ” Miller, deputy director for Policy and Strategic Communications within the Space Communications and Navigation Program at NASA Headquarters, told Insider in an interview.

Miller said many other countries have started looking to invest in deep-space navigation technology.

“Everyone has come to understand that this is an emerging user that is not going away, that we actually have to prepare and make the cis-lunar space, all the space between the Earth and the moon, as robust and reliable as possible with these signals,” he said.

Eventually, we’ll need a satellite navigation network around the moon

An infographic shows how the Moonlight initiative of ESA would work

In the second phase of ESA’s Moonlight, a network of satellites should help triangulate the position of spacecrafts at the surface.ESA-K Oldenburg/Insider

The signal from Earth’s satellites may get spacecraft all the way to the moon, but once they’re on the surface, the signal won’t be very useful.

At that point, these signals can only reach what’s visible from the Earth, so the dark side of the moon and moon poles are off-limits.

So the plan is to give the moon its very own fleet of communication and navigation satellites, called the Moonlight initiative. The first node in Moonlight would be NASA’s Pathfinder satellite.

Ventura-Traveset said ESA aims to test a basic infrastructure of Moonlight by 2027, and a more comprehensive infrastructure by 2030.

NASA is also working on building its own network, called LunaNet. NASA’s Gateway, a space station the agency aims to send to orbit the moon, would be another node in the network.

“We would imagine a kind of architecture that includes both NASA and ESA satellites working together,” NASA’s Miller said.

Moon settlers will need high-speed internet

An illustration shows a satellite and the Earth reflecting on the visor or a future moon astronaut.

Satellites could help future moon astronauts navigate on the moon, as can be seen in this artist’s impression.ESA

There is a more commercial aspect to bringing humans back to the moon. In the long run, moon settlers would need to set up camp so they can mine for minerals and water — which could be used to fuel rockets on the way to Mars.

Moon visitors will need to be able to communicate with Earth, talk to each other effectively, and be entertained, Ventura-Traveset said.

Down the line, moon settlers could have access to high-speed internet, video-conference with loved ones on Earth, stream shows, and create their own content from space, Ventura-Traveset said.

“I don’t think there’s anyone that would argue that that’s not the way we’re gonna go,” Ventura-Traveset said.

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Humans could one day live in Manhattan-sized asteroid megacities

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One problem remained, however. Asteroids are nowhere near large enough to provide enough gravity for a space habitat. What’s more, if they are spun around fast enough to create artificial gravity — as in the O-Neill cylinder concept — they would simply break apart, as they weren’t built and designed to have structural integrity like a spacecraft.

The solution to this problem is where the “wildly theoretical” part comes into play. The scientists posited that future space colonizers could wrap a massive mesh bag made of carbon nanofibers around an asteroid roughly the size of Bennu, which has a 300-meter diameter.

“Obviously, no one will be building asteroid cities anytime soon, but the technologies required to accomplish this kind of engineering don’t break any laws of physics,” explained physics professor Adam Frank, who worked on the project alongside a number of Rochester University students during the lockdown.

They would then rotate the asteroid to the point it breaks apart. All the rubble from the space rock would be caught in the nanofiber mesh, creating a hollowed-out outer layer that could be used as the exterior structure for a space habitat. Crucially, that layer of asteroid detritus would act as a shield against radiation. A cylinder used to spin the asteroid would create enough artificial gravity on the inner surface for a functioning space habitat.

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Early humans may have first walked upright in the trees

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An adult male chimpanzee walks upright to navigate flexible branches in the open canopy, characteristic of the Issa Valley savanna-mosaic habitat. Despite their open and dry habitat, chimpanzees at Issa remained highly arboreal and did not walk on the ground more than chimpanzees living in tropical forest, findings which support upright walking evolving in the trees, not on the ground in our early ancestors. Credit: Rhianna C. Drummond-Clarke

Human bipedalism—walking upright on two legs—may have evolved in trees, and not on the ground as previously thought, according to a new study involving UCL researchers.

In the study, published today in the journal Science Advances, researchers from UCL, the University of Kent, and Duke University, U.S., explored the behaviors of wild chimpanzees—our closest living relative—from the Issa Valley of western Tanzania, within the region of the East African Rift Valley.

Known as “savanna-mosaic”—a mix of dry open land with few trees and patches of dense forest—the chimpanzees’ habitat is very similar to that of our earliest human ancestors and was chosen to enable the scientists to explore whether the openness of this type of landscape could have encouraged bipedalism in hominins.

The study is the first of its kind to explore if savanna-mosaic habitats would account for increased time spent on the ground by the Issa chimpanzees, and compares their behavior to other studies on their solely forest-dwelling cousins in other parts of Africa.

Overall, the study found that the Issa chimpanzees spent as much time in the trees as other chimpanzees living in dense forests, despite their more open habitat, and were not more terrestrial (land-based) as expected.






A female chimpanzee walks upright to navigate flexible branches in the open canopy, characteristic of Issa Valley savanna-mosaic habitat. Despite their open and dry habitat, chimpanzees at Issa remained highly arboreal and did not walk on the ground more than chimpanzees living in tropical forest, findings which support upright walking evolving in the trees, not on the ground in our early ancestors. Credit: Rhianna C. Drummond-Clarke

Furthermore, although the researchers expected the Issa chimpanzees to walk upright more in open savanna vegetation, where they cannot easily travel via the tree canopy, more than 85% of occurrences of bipedalism took place in the trees.

The authors say that their findings contradict widely accepted theories that suggest that it was an open, dry savanna environment that encouraged our prehistoric human relatives to walk upright—and instead suggests that they may have evolved to walk on two feet to move around the trees.

Study co-author Dr. Alex Piel (UCL Anthropology) said, “We naturally assumed that because Issa has fewer trees than typical tropical forests, where most chimpanzees live, we would see individuals more often on the ground than in the trees. Moreover, because so many of the traditional drivers of bipedalism (such as carrying objects or seeing over tall grass, for example) are associated with being on the ground, we thought we’d naturally see more bipedalism here as well. However, this is not what we found.

“Our study suggests that the retreat of forests in the late Miocene-Pliocene era around five million years ago and the more open savanna habitats were in fact not a catalyst for the evolution of bipedalism. Instead, trees probably remained essential to its evolution—with the search for food-producing trees a likely a driver of this trait.”

A young male from the Issa Valley community feeds on seed pods during a foraging session. This woodland pod is a favoured food of the Issa chimpanzees during dry season, and grows on large trees with open canopy. Despite their open and dry habitat, chimpanzees at Issa remained highly arboreal and did not walk on the ground more than chimpanzees living in tropical forest, findings which support upright walking evolving in the trees, not on the ground in our early ancestors. Credit: Rhianna C. Drummond-Clarke

To establish their findings, the researchers recorded more than 13,700 instantaneous observations of positional behavior from 13 chimpanzee adults (six females and seven males), including almost 2,850 observations of individual locomotor events (e.g., climbing, walking, hanging, etc.), over the course of the 15-month study. They then used the relationship between tree/land-based behavior and vegetation (forest vs. woodland) to investigate patterns of association. Similarly, they noted each instance of bipedalism and whether it was associated with being on the ground or in the trees.

The authors note that walking on two feet is a defining feature of humans when compared to other great apes, who “knuckle walk.” Yet, despite their study, researchers say why humans alone amongst the apes first began to walk on two feet still remains a mystery.

Study co-author Dr. Fiona Stewart (UCL Anthropology) said, “To date, the numerous hypotheses for the evolution of bipedalism share the idea that hominins (human ancestors) came down from the trees and walked upright on the ground, especially in more arid, open habitats that lacked tree cover. Our data do not support that at all.

“Unfortunately, the traditional idea of fewer trees equals more terrestriality (land dwelling) just isn’t borne out with the Issa data. What we need to focus on now is how and why these chimpanzees spend so much time in the trees—and that is what we’ll focus on next on our way to piecing together this complex evolutionary puzzle.”

More information:
Rhianna Drummond-Clarke et al, Wild chimpanzee behavior suggests that a savanna-mosaic habitat did not support the emergence of hominin terrestrial bipedalism, Science Advances (2022). DOI: 10.1126/sciadv.add9752. www.science.org/doi/10.1126/sciadv.add9752

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It’s 50 Years Since Humans Were on the Moon: Why We Left and We’re Returning Soon

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Famously, the Apollo 11 astronauts laid down the first human boot prints on the surface of the moon, in July of 1969. It’s a little less well known that the last prints from human activity on our lone natural satellite were imprinted just three-and-a-half years later.

Astronauts Eugene A. Cernan, Ronald E. Evans and Harrison H. “Jack” Schmitt conducted a 12-day mission to the Taurus-Littrow region of the moon, during which time they collected more moon rocks and other geological samples than any other Apollo mission. On the way to their destination, they also captured the iconic “blue marble” image of Earth, which gave humanity one of the best views of our home up to that point in history. 

As the Apollo 17 crew left the moon on Dec. 14, 1972, Cernan commemorated the moment by telling Mission Control: “We leave as we came, and, God willing, we shall return, with peace and hope for all mankind.” 

Cernan lived until 2017 but didn’t live to see the return he spoke of on that historic trip. 

In total, only 12 people have set foot on the moon in the multibillion-year history of the rock, and they all visited over a single 38-month period. 

Why we moved on from the moon

The creation of NASA has its roots in Cold War anxieties and the space race between the United States and the Soviet Union. The Soviets were out of the gate quick with the successful launch of the first satellite, Sputnik, and the first person in space, Yuri Gargarin. Apollo 17 came a full decade after President John F. Kennedy’s bold 1962 promise to land men on the moon before the decade was out. NASA not only met its self-imposed deadline, it went back a handful of times too. 

But a lot of other things were happening on Earth at the time. An unpopular war raged in Southeast Asia, and civil unrest in the streets of American cities led evening newscasts, to say nothing of the multiple environmental crises that were becoming mainstream concerns. The US government had sunk a massive amount of taxpayer money into Apollo, and the program’s popularity was waning just a few months after Neil Armstrong‘s “giant leap for mankind” captivated the world. 

Taller than the Statue of Liberty, the Saturn V Heavy Lift Vehicle rocket was a key piece of NASA history. The space agency built it to help get astronauts to the moon. “The rocket generated 34.5 million newtons (7.6 million pounds) of thrust at launch, creating more power than 85 Hoover Dams,” says NASA. Saturn V first flew in 1967 for the Apollo 4 mission. The last Saturn V took off in 1973 and ferried the Skylab space station into Earth orbit. This image shows the Skylab launch.


NASA

“Running parallel with the social revolution of the 1960s, Apollo experienced many incredible triumphs as well as tremendous setbacks (cancellation of several final missions) and tragedies (Apollo 1),” writes NASA chief historian Brian Odom in a recent blog post.

In January of 1970, all Apollo missions beyond Apollo 17 were canceled due to cuts in federal funding. The threat of Soviets in space was no longer top of mind for most Americans, who were facing a recession and rising inflation, a harbinger of a tough economic decade to come in the 1970s.

After Apollo, NASA’s focus shifted to orbit, first with the Skylab space station and hen with a space shuttle program that ran for three decades until 2011. 

So this Wednesday marks a full half-century since the most recent moment there was any human presence, not just on the moon, but anywhere beyond low Earth orbit.

Space shuttle Atlantis touched down after its final mission in July 2011. This image comes from a sequence of landing shots and shows the shuttle’s drag chute, used to slow down the spacecraft. This landing also marked the end of NASA’s iconic space shuttle program. 


Kenny Allen/NASA

Making a home in space

To be fair, we’ve kept our astronauts quite busy in orbit, where the International Space Station remains one of history’s most notable examples of international cooperation. Today, with European and American relations with Russia at their lowest point since at least 1991, Russian cosmonauts and astronauts continue to live and work together productively, even when leadership on the surface starts a little saber-rattling.

Priorities began to shift a bit once again as the shuttle was winding down in the late 2000s. A new push to return to the moon and continue on to Mars began to gain momentum, both inside and outside NASA. The US Congress committed to invest billions to build a huge new rocket, while Elon Musk and SpaceX were building toward similar ambitions.  

Unrealized futuristic predictions from the mid-20th century imagining how we would live on sci-fi space stations and explore Mars returned to the zeitgeist.

Almost exactly a half century after Apollo 17, NASA’s uncrewed Artemis I mission earlier this month traveled further beyond the moon than any human-rated spacecraft ever, and it captured a new iconic image for a new generation of exploration, showing both the moon and Earth from a new perspective. 

Orion, the moon and Earth appear together in a photo. 


NASA

NASA and SpaceX have committed to joining forces to return a new generation of astronauts to the surface of the moon before the decade is out. It’s a familiar promise, which worked out last time.

It’s probably no coincidence that some of the circumstances from the original space race are beginning to replay today, too, with a new geopolitical rival, China, increasingly pushing forward an ambitious space exploration agenda. China’s space program is currently launching dozens of rockets each year and operating its own space station, lunar and Mars rovers. The Chinese space agency has also stated its goal of building a crewed station on the surface of the moon, which is also a primary goal of NASA’s Artemis program. 

NASA historian Odom points out that much of the lasting legacy of the Apollo program is still present on Earth. 

“The federal investment in aerospace infrastructure across the southern United States transformed the economics of much of the region. Critical investments in university engineering and science programs created foundations that continue to pay off with technological and scientific breakthroughs.”

Odom is optimistic that Artemis will yield a new round of scientific discoveries and engineering innovations. 

“Hopefully the lessons of Apollo will prove a helpful framework for discovery both on the moon and back home. If we are paying attention, I am sure they will.”

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