Thursday, February 03, 2022

OUR FRIENDS THE FUNGI

The ancient, intimate relationship between trees and fungi, from fairy toadstools to technicolour mushrooms

by Gregory Moore, Mark Brundrett, The Conversation

You may be familiar with the red toadstool with white spots, which are often the homes of fairies in children's stories. These toadstools are also a small part of grander magical story: they are striking examples of mycorrhizas.

Mycorrhizas (pronounced my-cor-rye-zas) is the name for fungi associated with the root systems of many plants including trees, shrubs, groundcovers and grasses. These relationships are mutually symbiotic, which means both members benefit.

Fungi have a deeply ancient evolutionary origin, and colonized land with the first plants around 500 million years ago to form these partnerships. We humans often underestimate their importance to the ecosystems that have shaped life on earth.

So let's take a closer look at how this relationship works and why it's so important for Australian ecosystems.

An intimate relationship

Fungi come in a beautiful diversity of shapes, sizes and colors. The following photos by my co-author Mark Brundrett are just a few examples of those growing in southwest Australia.

Mycorrhizas are not to be confused with fungi that decompose dead plant matter (saprophytes) or those that cause disease (pathogens).

Saprophytes are fungi that recycle nutrients, and these can also be large and impressive. They can create tree hollows, which provide shelter for nesting birds and other animals such as possums.

The ethereal ghost fungus, for example, is a saprophyte. It famously glows green in the dark, and recycles nutrients in ecosystems by breaking down dead wood.

The primary role of mycorrhizas, on the other hand, is to provide resources such as phosphorus and nitrogen to flowering plants. They also effectively increase the absorptive surface area of the plant's root system, allowing plants to take up much-needed water and nutrients so they grow better and more quickly.

In return, the plants provide carbohydrates, a product of photosynthesis, which mycorrhizas require to grow.

There are five different types of mycorrhizas, and two of these are particularly important in Australian ecosystems. One type is called "ectomycorrhiza," where fungi wrap their hyphae (long, very fine hair-like structures that contact the soil) around the plant roots underground but don't penetrate the root cells.

The other, called "endomycorrhiza," is where fungi grow into the plant root, penetrating and branching within the root cells to form what look like little, microscopic trees. This is about as intimate a relationship between different types of organisms as you can get!

Arbuscular mycorrhizas are tiny tree-like growths inside the root cell where materials are

exchanged with the host plant. Credit: Mark Brundrett, Author provided

Mushrooms as big as dinner plates

We often become aware of the presence of mycorrhizas only when conditions for reproduction are right, and a mushroom or toadstool emerges from the ground. Such conditions may only occur every five to ten years. For some species, there may be centuries between reproductive events.

For many of us, our experience with mycorrhizal fungi begins in very early childhood when we first catch sight of those spotty red and white toadstools, called the fly agaric or Amanita muscaria.

These fungi are often depicted in children's book illustrations, such as Little Red Riding Hood, Jack and the Beanstalk, and a number of Enid Blyton's tales. I recall conifers, such as pine trees, often growing nearby in the background of these pictures. This was no coincidence, Amanita muscaria forms mycorrhizal associations with many conifers, as well as oaks.

The mycorrhizal fungi associated with eucalypts can be less showy, with many being 75–100 millimeters across and a creamy, light tan in color. They quite often pop up in home gardens, frequently in lawns, where they're very obvious and usually within 4 to 5 meters of a tree trunk.

Others are spectacular, including the bright purple, orange or green Cortinarius species shown in the photos below. In fact, the beauty and diversity of our fungi now supports a new ecotourism industry in Australia, particularly in Tasmania.

BRIGHT GREEN FROM GROWING IN EUCALYPTUS FOREST

Some fungi are most impressive in the spring following bushfires, such as the abundant orange cup fungus that stabilizes ash beds.

Indeed, most plants form mycorrhizal associations. Those that don't include plants from the common vegetable families brassicaceae (think broccoli, cauliflower, kale) and chenopodiaceae (spinach, beetroot, and quinoa). Neither do members of the proteaceae family, such as native banksias and grevilleas. These plants invest in very complex roots rather than fungal associations.

Who's really in control?

Because we are so familiar with many of the plants in our environment, we are inclined to think it's them that control their relationship with mycorrhizal fungi.

But it is possible mycorrhizal fungi exercise much more control. Or perhaps, the relationship is a perfect mutualistic symbiosis where partners share everything, including control, equally. We just don't know yet.

Members of the fungus kingdom work in synchrony with the plant kingdom to support all terrestrial life, including animals such as ourselves. We may not think about fungi very often, but we cannot survive without them.

One of the surprise elements of Douglas Adam's Hitchhiker's Guide to the Galaxy, was that the Earth and its inhabitants existed as part of an experiment designed and controlled by white laboratory mice.

I sometimes wonder if the fate of the Earth's terrestrial ecosystems rests on mycorrhizal fungi. If so, perhaps we need to show them greater respect.

Underground fungal relationships key to thriving plants

Provided by The Conversation

This article is republished from The Conversation under a Creative Commons license. Read the original article.

'Insect apocalypse' looming under current conservation rules

by University of Aberdeen

Current UK conservation policies fail to protect important insect species such as bees which "are vital for our everyday lives and future existence," according to new research from the University of Aberdeen.

Love them or loathe them, insects provide a wealth of daily resources, from chocolates to cold remedies but researchers Natalie Duffus and Dr. Juliano Morimoto warn that current conservation policies are falling short of protecting them from the threat of extinction.

Published in Biological Conservation today the researchers assert that current policies are biased and ineffective and are failing to protect a large portion of insect biodiversity in the UK and Ireland.

The team analyzed key conservation policies already in place and found that some groups of insects including butterflies and moths were more stringently protected than others, such as flies and bees, species that are known to be equally important and which have undergone recent known extinctions in the UK and Ireland.

Natalie Duffus, the lead author who is currently a Natural Environment Research Council doctoral trainee at the University of Oxford but completed the research while an undergraduate at the University of Aberdeen, explains: "Insects fulfill a range of vital roles in the ecosystem, including pollination, pest control, and decomposition.

Credit: University of Aberdeen

"These services are important not only for maintaining healthy ecosystems, but also for a range of human needs, for example crop pollination by insects contributes directly toward food security.

"Unfortunately, data shows that some insect species are declining. This could have a direct impact on the roles insects play in our societies.

"Policies such as those evaluated in our study are the strictest way in which protection can be enforced. However, our study shows that these policies are failing in doing their job by being biased and not accounting for the breadth of insect biodiversity."

The study evaluated current conservation policies in the UK and Ireland including the Wildlife and Countryside Act 1981, Wildlife Order 1985 and Wildlife Act 1976. It found that insects were largely overlooked when compared with the protection to mammals.

Natalie added: "We hope our findings will stimulate policy revisions and amendments and fuel the push for better initiatives for insect biodiversity."

Research fellow at the University of Aberdeen and project lead Dr. Juliano Morimoto said: "This research is vital as it shows our policies are failing to protect the majority of insects, and those insects that are protected, may not be the ones in most need. Our study reveals this major gap in our legislation and is likely to reflect a global pattern. Such policy gaps, if overlooked, can have catastrophic damage to the sustainable future of our societies."Insect DNA metabarcoding to assess the state of health of forests

More information: Current conservation policies in the UK and Ireland overlook endangered insects and are taxonomically biased towards Lepidoptera. Biological Conservation, doi.org/10.1016/j.biocon.2022.109464

Journal information: Biological Conservation

Provided by University of Aberdeen

Physicists manipulate magnetism with light

by Elizabeth A. Thomson, Materials Research Laboratory, Massachusetts Institute of Technology

With the help of a "playground" they created for observing exotic physics, MIT scientists and colleagues have not only found a new way to manipulate magnetism in a material with light but have also realized a rare form of matter. The former could lead to applications including computer memory storage devices that can read or write information in a much faster way, while the latter introduces new physics.

A solid material is composed of different types of elementary particles, such as protons and neutrons. Also ubiquitous in such materials are "quasiparticles" that the public is less familiar with. These include excitons, which are composed of an electron and a "hole," or the space left behind when light is shone on a material and energy from a photon causes an electron to jump out of its usual position. Through the mysteries of quantum mechanics, however, the electron and hole are still connected and can "communicate" with each other through electrostatic interactions.

"Excitons can be thought of as packets of energy that propagate through a system," says Edoardo Baldini, one of two lead authors of a paper on the work in Nature Communications. Baldini, now a professor at the University of Texas at Austin, was an MIT postdoctoral associate when the work was conducted in the laboratory of Nuh Gedik, an MIT professor of physics. The other lead author is Carina Belvin, a doctoral student in the Gedik group.

"The excitons in this material are rather unique in that they are coupled to magnetism in the system. It was quite impressive to be able to "kick" the excitons with light and observe the associated changes in the magnetism," says Gedik, who is also associated with MIT's Materials Research Laboratory.

Manipulating Magnetism

The current work involves the creation of unusual excitons in the material nickel phosphorus trisulfide (NiPS3). These excitons are "dressed" or affected by the environment that surrounds them. In this case that environment is the magnetism. "So what we found is that by exciting these excitons we can actually manipulate magnetism in the material," Belvin says.

A magnet works because of a property of electrons called spin (another, more familiar property of electrons is their charge). The spin can be thought of as an elementary magnet, in which the electrons in an atom are like little needles orienting in a certain way. In the magnets on your refrigerator, the spins all point in the same direction, and the material is known as a ferromagnet. In the material used by the MIT team, alternating spins point in opposite directions, forming an antiferromagnet.

The physicists found that a pulse of light causes each of the little electron "needles" in NiPS3 to start rotating around in a circle. The rotating spins are synchronized and form a wave throughout the material, known as a spin wave. Spin waves can be used in spin electronics, or spintronics, a field that was introduced in the 1960s.

Spintronics essentially uses electrons' spin to go beyond electronics, which is based on their charge. The ability to create spin waves in an antiferroelectric material could lead to future computer memory devices that can read or write information in a much faster way than those based on electronics alone. "We are not there yet. In this paper we've demonstrated a process that underlies coherent domain switching: the next step is to actually switch domains," Baldini says.

Rare Form of Matter

Through their work, the team also demonstrated a rare form of matter. When the physicists exposed NiPS3 to intense pulses of light, they found that it turned into a metallic state that conducts electrons while maintaining its magnetism. NiPS3 is ordinarily an insulator (a material that does not conduct electrons). "It is very rare to have an antiferromagnet and a metallic state in the same material," Belvin says.

The physicists believe this happens because the intense light causes the excitons to collide with each other and break apart into their constituents: electrons and holes. "We are basically destroying the excitons, so that the electrons and holes can move around like those in a metal," Baldini says. But these mobile particles do not interact with the localized electron spins participating in the spin wave, so the magnetism is retained.

Baldini describes the experimental setup as a "playground for observing many-body physics," which he defines as "the elegant interplay between different bodies like excitons and spin waves." He concludes, "what I really liked about this work was that it shows the complexity of the world around us."

Other authors of the paper from MIT are Professor of Physics Senthil Todadri, Ilkem Ozge Ozel (Ph.D. '18), Dan Mao (Ph.D. '21, now at Cornell University), Hoi Chun Po (postdoctoral fellow '18-'21, now at Hong Kong University of Science and Technology), and Clifford Allington (a graduate student in chemistry). Additional authors are Suhan Son, Inho Hwang, and Je-Geun Park of the Institute for Basic Science (Korea) and Seoul National University; Beom Hyun Kim of the Korea Institute for Advanced Study; and Jae Hoon Kim and Jonghyeon Kim of Yonsei University.Physicists detect a hybrid particle held together by uniquely intense 'glue'

More information: Carina A. Belvin et al, Exciton-driven antiferromagnetic metal in a correlated van der Waals insulator, Nature Communications (2021). DOI: 10.1038/s41467-021-25164-

Journal information: Nature Communications

Provided by Materials Research Laboratory, Massachusetts Institute of Technology

FARTS IN SPACE
ASTRONAUT WARNS TOM CRUISE ABOUT APPALLING SMELL ON SPACE STATION

"WHEN YOU GO INTO THE MODULE THAT HAS THE LIFTING, THE STRENGTH TRAINING EQUIPMENT, THAT'S ALSO WHERE THE BATHROOM IS."

Eau de Space

NASA astronaut Victor Glover sat down for a chat with Hollywood actor Tom Cruise to prepare him for what it’s really like to spend time on board the International Space Station — and it sounds like a surprisingly nose-crinkling experience.

Glover, who was part of the first operational crew mission to the ISS on board SpaceX’s Crew Dragon spacecraft in November 2020, gave Cruise several pointers as to what to expect. Cruise partnered with SpaceX in 2020 to film what could soon become one of the first action movies filmed in space.

During an interview for the NASA podcast “The Body in Space” — originally recorded in November, but published Friday — Glover didn’t beat around the bush.

“When you first get to space station is when you notice the smell the strongest because you kind of get saturated and you get used to it after, but it was an interesting combination,” Glover told Cruise after he asked about the experience of living on board the orbiting space lab.

“And again, it’s also local,” he went on. “When you go into the module that has the lifting, the strength training equipment, that’s also where the bathroom is. So, that’s the most odoriferous module.”

“That one smells like a locker room,” he said, also likening the overall odor of the station to the smell at a hospital.
Rocket Man

Glover also recalled what it was like riding a SpaceX Falcon 9 rocket.

“It is such a high-performing liquid rocket,” he said. “It’s smooth, but it really leapt off the pad. And we got to the 100-kilometer point, and we were all smiles. It was just so amazing.”

He also warned Cruise that spacewalks are no cake walk.

“You’re moving around a suit that can weigh, with your body, as much as a thousand pounds [editor’s note: according to NASA’s documentation, an astronaut in an extravehicular suit weighs closer to 500 pounds], and you very rarely use your legs,” he told the actor. “It’s like running two marathons but on your hands the whole time.”

Despite Glover’s return to Earth going by without a hitch, he recalled a familiar sensation.

“However, it was at that time, I’m now back in 1 g, I feel my 200 pounds, and that’s when I noticed I had to pee,” he told Cruise. “I could also feel the weight of my bladder for the first time, and it was a really interesting sensation.”

READ MORE: The Body in Space [NASA]

More on the ISS: NASA Astronaut Touts the Benefits of Drinking Russian Pee

Richard von Krafft-Ebing and Deviant Sexual Behaviour - SciHi BlogSciHi Blog

Did comet's fiery destruction lead to downfall of ancient Hopewell?

by Michael Miller, University of Cincinnati

The rapid decline of the Hopewell culture about 1,500 years ago might be explained by falling debris from a near-Earth comet that created a devastating explosion over North America, laying waste to forests and Native American villages alike.

Researchers with the University of Cincinnati found evidence of a cosmic airburst at 11 Hopewell archeological sites in three states stretching across the Ohio River Valley. This was home to the Ohio Hopewell, part of a notable Native American culture found across much of the American East.

The comet's glancing pass rained debris down into the Earth's atmosphere, creating a fiery explosion. UC archeologists used radiocarbon and typological dating to determine the age of the event.

The airburst affected an area bigger than New Jersey, setting fires across 9,200 square miles between the years A.D. 252 and 383. This coincides with a period when 69 near-Earth comets were observed and documented by Chinese astronomers and witnessed by Native Americans as told through their oral histories.

The study was published in the Nature journal Scientific Reports.

UC archeologists found an unusually high concentration and diversity of meteorites at Hopewell sites compared to other time periods. The meteorite fragments were identified from the telltale concentrations of iridium and platinum they contained. They also found a charcoal layer that suggests the area was exposed to fire and extreme heat.

In his lab, lead author Kenneth Tankersley, a professor of anthropology in UC's College of Arts and Sciences, held up a container of tiny micrometeorites collected at the sites. A variety of meteorites, including stony meteorites called pallasites, were found at Hopewell sites.

"These micrometeorites have a chemical fingerprint. Cosmic events like asteroids and comet airbursts leave behind high quantities of a rare element known as platinum," Tankersley said. "The problem is platinum also occurs in volcanic eruptions. So we also look for another rare element found in nonterrestrial events such as meteorite impact craters—iridium. And we found a spike in both, iridium and platinum.

The Hopewell people collected the meteorites and forged malleable metal from them into flat sheets used in jewelry and musical instruments called pan flutes.

Beyond the physical evidence are cultural clues left behind in the masterworks and oral histories of the Hopewell. A comet-shaped mound was constructed near the epicenter of the airburst at a Hopewell site called the Milford Earthworks.

Various Algonquin and Iroquoian tribes, descendants of the Hopewell, spoke of a calamity that befell the Earth, said Tankersley, who is Native American.

"What's fascinating is that many different tribes have similar stories of the event," he said.

"The Miami tell of a horned serpent that flew across the sky and dropped rocks onto the land before plummeting into the river. When you see a comet going through the air, it would look like a large snake," he said.

"The Shawnee refer to a 'sky panther' that had the power to tear down forest. The Ottawa talk of a day when the sun fell from the sky. And when a comet hits the thermosphere, it would have exploded like a nuclear bomb."

And the Wyandot recount a dark cloud that rolled across the sky and was destroyed by a fiery dart, Tankersley said.

"That's a lot like the description the Russians gave for Tunguska," he said of a comet airburst documented over Siberia in 1908 that leveled 830 square miles of forest and shattered windows hundreds of miles away.

"Witnesses reported seeing a fireball, a bluish light nearly as bright as the sun, moving across the sky. A flash and sound similar to artillery fire was said to follow it. A powerful shockwave broke windows hundreds of miles away and knocked people off their feet," according to a story in EarthSky.

UC biology professor and co-author David Lentz said people who survived the airburst and its fires would have gazed upon a devastated landscape.

"It looks like this event was very injurious to agriculture. People didn't have good ways to store corn for a long period of time. Losing a crop or two would have caused widespread suffering," Lentz said.

And if the airburst leveled forests like the one in Russia, native people would have lost nut trees such as walnut and hickory that provided a good winter source of food.

"When your corn crop fails, you can usually rely on a tree crop. But if they're all destroyed, it would have been incredibly disruptive," Lentz said.

UC's Advanced Materials Characterization Center conducted scanning electron microscopy and energy dispersive spectrometry of the sediment samples. Inductively coupled plasma mass spectrometry was employed at the University of Georgia's Center for Applied Isotope Studies. The U.S. Geological Survey provided stable carbon isotope analysis.

Despite what scientists know, there is still much they do not, Lentz said.

"It's hard to know exactly what happened. We only have a few points of light in the darkness," he said. "But we have this area of high heat that would have been catastrophic for people in that area and beyond."

Now researchers are studying pollen trapped in layers of sediment to see how the comet airburst might have changed the botanical landscape of the Ohio River Valley.

Co-author Steven Meyers, a UC geology alumnus, said their discovery might lead to more interest in how cosmic events affected prehistoric people around the world.

"Science is just a progress report," Meyers said. "It's not the end. We're always somewhere in the middle. As time goes on, more things will be found."Vast patches of glassy rock in Chilean desert likely created by ancient exploding comet

More information: Kenneth Barnett Tankersley et al, The Hopewell airburst event, 1699–1567 years ago (252–383 CE), Scientific Reports (2022). DOI: 10.1038/s41598-022-05758-y

Journal information: Scientific Reports

Provided by University of Cincinnati

China’s Mars Orbiter Sends Back Selfie Video for the Lunar New Year

JARON SCHNEIDER
FEB 01, 2022
Tianwen-1 Selfie Video over Mars

The Chinese Mars orbiter Tianwen-1 has sent back a selfie video that shows its orbit around Red Planet. The clip was published in celebration of the Lunar New Year and shows both the orbiter and Mars below it as it zooms around the planet.

A Timelapse Video Selfie

Xinhua News, a Chinese state-affiliated media source, published the video on Monday, the eve of the Chinese Lunar New Year. The video was provided by the China National Space Administration (CNSA) and shows the orbiter’s engine, propellant tank, altitude controller, and other components. Xinhua says that the video proves that the Tianwen-1 is in “good condition.”

China’s flag can be seen prominently placed in the center-left of the frame (very likely on purpose) as the orbiter’s solar array moves in concert with the sun’s direction

The Tianwen-1 is Nearing its One-Year Anniversary

China’s Tianwen-1 is closing in on one year of orbiting Mars as it reached the Red Planet on February 10, 2021. Initially launched on July 23, 2020, the orbiter has been working for 557 consecutive days and has sent back 600GB of science data according to the CNSA

The Tianwen-1 took the trip to Mars with the Zhurong Rover, which has been deployed on the planet for 255 Martian days and has driven a total of 1,524 meters on the surface. In early January, that travel distance was 1,400 meters and the CNSA said that the rover had already outlived its three-month life expectancy. Now into February, the rover adds another month and 124 more meters traveled to those marks.

Also last month, China published several other photos of the Tianwen-1 in a move that is far more transparent than the country normally is with regard to its space program; The Verge notes that China is fairly vague when it comes to the information it chooses to release about launches and its spacecraft.

Tianwen-1 over mars

Notably, the Zhurong Rover has a detachable camera that allowed it to take a photo of itself from an angle that is different from those captured by NASA’s Mars rovers.

China’s repeated statements to the health of the Tianwen-1 and the Zhurong rover point to the likelihood that this is far from the last time the CNSA will share photos and video captured from the mission. After its conclusion, China is currently working on another mission, likely to be named Tianwen-2, that will aim to collect rock samples from Mars and return them to Earth in 2030.

27,000 man-made objects in Earth orbit, and counting: Space junk is here to stay

Space junk includes old satellites, rocket bodies, and fragments of exploded or decaying spacecraft

Press Trust of IndiaFebruary 02, 2022

Representational image. News18

Adelaide: The US Vanguard 1 satellite and the rocket stage that delivered it to orbit in 1958 are pieces of cultural heritage. They date from a time when humans first attained the capability of reaching beyond our home planet to the stars. They also have the dubious honour of being the first space junk'.

NASA estimates there are around 27,000 human-made objects larger than 10 centimetres that can be classified as space junk that is, they do not have a useful purpose, either now or in the foreseeable future. These include old satellites, rocket bodies, and fragments of exploded or decaying spacecraft. The smaller bits, down to dust grain-size, number in the millions.

The problem is that collisions between this high-speed trash create more space junk. The worst-case scenario is known as Kessler Syndrome, an unstoppable cascade of collisions that could make parts of Earth orbit unusable.

It's an increasingly pressing situation as private corporations like SpaceX are slated to launch up to 100,000 new satellites by the end of the decade. Anti-satellite missiles, like the one tested by Russia in 2021, can add hundreds to thousands of new debris pieces in one event.

One of the big problems is we don't know enough about where what and how much space junk there is. This means we don't always know when a piece of space junk is about to collide with something, or how far we really are from Kessler Syndrome. This is a problem firstly, of observation and tracking, and secondly, of modelling and simulation of this highly complex data.

Lots of blind spots' are yet to be covered, like the tiny fragments and dust, and the higher orbits which are difficult to see from Earth's surface. Adding new instruments and techniques for observing space junk will address this.

For example, LeoLabs built a new space radar in New Zealand in 2019, picking up some of the blind spots in the Pacific region. HEO Robotics is developing observing capabilities in Earth orbit which can monitor the condition of spacecraft.

An increasingly popular approach is space traffic management. This aims to use space more efficiently and sustainably by coordinating and sharing information, such as that needed to avoid collisions, at the international and agency level.

International cooperation, of course, is an essential part of the solution. The Interagency Space Debris Coordination Committee (IADC) facilitates cooperation in space debris research, and monitors the progress of ongoing cooperative activities. The IADC recommends each mission has a debris mitigation management plan.

The UN through the Office of Outer Space Affairs and the Committee on the Peaceful Uses of Outer Space is also a key international organisation.

The UN released the Guidelines for the Long-term Sustainability of Outer Space Activities in 2018. Among other things, the guidelines emphasise the role of national governments in ensuring satellite operators under their jurisdiction don't contribute to the debris problem.

The UN, NASA and European Space Agency have had guidelines on design for minimising debris for nearly thirty years. The recommendations for end-of-life planning state that no spacecraft should remain in its mission orbit for longer than 25 years. Many think even this is too long.

Another end-of-life strategy is to passivate' a spacecraft. Here, all of the fuel, battery power, and high-pressure liquids are expended or exhausted, to reduce the risk of explosion.

But by some estimates, up to 60 percent of all new satellites launched don't comply with debris mitigation guidelines. It seems the incentives to preserve space for future generations aren't yet enough to sway commercial and government operators.

So what about cleaning up orbit? How can we remove the junk that is already up there?

Natural decay is the do-nothing strategy. Earth's atmosphere acts as a space junk waste management system by dragging objects into it, where friction and compression heat them to a burning point.

Eventually, everything below about 1,000 kilometres will get dragged back in.
The problem, of course, is that we keep adding new stuff, and it could be hundreds or even thousands of years before some junk re-enters.

Additionally, there's growing evidence that this is not the ideal solution it appears. The incineration creates alumina and soot particulates that cause the Earth's protective ozone layer to decay a problem we thought we'd already solved.

Options for active removal include nudging objects into the atmosphere, or pushing them to less congested orbits, also known as graveyard orbits, where they aren't such a collision risk a choice of down or up.

Methods which have been proposed or are under development include nets, harpoons, lasers, tethers, sails and specialised vehicles. In 2019, Surrey Satellite Technology (SSTL) successfully tested a harpoon for space junk capture in orbit.

The leaders in this field are Singapore-based Astroscale. In collaboration with SSTL, they launched the Elsa-d system in March 2021. Elsa-d is testing rendezvous manoeuvres needed to dock with space junk and then remove it.

Another project is the Swiss ClearSpace1. Under contract to the European Space Agency, they are developing a spider-clawed spacecraft to grab and de-orbit old satellites. It's planned for launch in 2025.

Getting rid of old space junk doesn't have to mean destruction. Recycling could give space junk a purpose making it a resource rather than rubbish. For example, old satellites aren't always dead'. They may have power and communications and could be repurposed to do new science.

The materials could be recycled into rocket fuel, technology which Neumann Space is developing in Australia, or scavenged for building materials. Old rocket bodies, one of the most dangerous classes of junk, could be turned into space habitats or laboratories.

However, passivation reduces the potential for repurposing a satellite or rocket body. Refuelling on-orbit is a way to extend the usable life of a spacecraft, and a number of companies are working on this technology.

Another promising direction is thinking creatively about new materials. A Japanese project has been looking at wood as housing for small, short-lived low Earth orbit satellites. Wood won't last as long in orbit as the usual spacecraft materials and does not create alumina or soot when it burns in the upper atmosphere.

The problem with any successful technology for removing an old spacecraft from orbit is that it's also effectively an anti-satellite weapon. This means treading very carefully indeed to avoid the situation that no-one wants war in space.

Earth orbit is a classic example of the tragedy of the commons', where maximising national, or commercial, gain ruins the resource for all users. It's important to remember that not everyone is equally responsible for creating space junk. Most of it belongs to the US, Russia and China. But the advent of the private mega constellations is likely to change that.

One thing is clear: orbital space is never going to return to its pre-1957 pristine state. Space junk is here to stay.

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Thursday, February 03, 2022

The ancient, intimate relationship between trees and fungi, from fairy toadstools to technicolour mushrooms

A Timelapse Video Selfie

The Tianwen-1 is Nearing its One-Year Anniversary

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