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According to the United Nations, the world produces about 430 million metric tons (267 U.S. tons) of plastic annually, two-thirds of which are only used for a short time and quickly become garbage. What’s more, plastics are the most harmful and persistent fraction of marine litter, accounting for at least 85% of total marine waste. This problem is easily recognizable due to the Great Pacific Garbage Patch and the amount of plastic waste that washes up on beaches and shores every year. Unless measures are taken to address this problem, the annual flow of plastic into the ocean could triple by 2040.

One way to address this problem is to improve the global tracking of plastic waste using Earth observation satellites. In a recent study, a team of Australian researchers developed a new method for spotting plastic rubbish on our beaches, which they successfully field-tested on a remote stretch of coastline. This satellite imagery tool distinguishes between sand, water, and plastics based on how they reflect light differently. It can detect plastics on shorelines from an altitude of more than 600 km (~375 mi) – higher than the International Space Station‘s (ISS) orbit.

The paper that describes their tool, “Beached Plastic Debris Index; a modern index for detecting plastics on beaches,” was recently published by the Marine Pollution Bulletin. The research team was led by Jenna Guffogg, a researcher at the Royal Melbourne Institute of Technology University (RMIT) and the Faculty of Geo-Information Science and Earth Observation (ITC) at the University of Twente. She was joined by multiple colleagues from both institutions. The study was part of Dr. Guffogg’s joint PhD research with the support of an Australian Government Research Training Program (RTP) scholarship.

Dr Jenna Guffogg said plastic on beaches can have severe impacts on wildlife and their habitats, just as it does in open waters. Credit: BPDI

According to current estimates, humans dump well over 10 million metric tons (11 million U.S. tons) of plastic waste into our oceans annually. Since plastic production continues to increase worldwide, these numbers are projected to increase dramatically. What ends up on our beaches can severely impact wildlife and marine habitats, just like the impact it has in open waters. If these plastics are not removed, they will inevitably fragment into micro and nano plastics, another major environmental hazard. Said Dr. Guffogg in a recent RMIT University press release:

“Plastics can be mistaken for food; larger animals become entangled, and smaller ones, like hermit crabs, become trapped inside items such as plastic containers. Remote island beaches have some of the highest recorded densities of plastics in the world, and we’re also seeing increasing volumes of plastics and derelict fishing gear on the remote shorelines of northern Australia.

“While the impacts of these ocean plastics on the environment, fishing and, tourism are well documented, methods for measuring the exact scale of the issue or targeting clean-up operations, sometimes most needed in remote locations, have been held back by technological limitations.”

Satellite technology is already used to track plastic garbage floating around the world’s oceans. This includes relatively small drifts containing thousands of plastic bottles, bags, and fishing nets, but also gigantic floating trash islands like the Great Pacific Garbage Patch. As of 2018, this garbage patch measured about 1.6 million km2 (620,000 mi2) and consisted of 45,000–129,000 metric tons (50,000–142,000 U.S. tons). However, the technology used to locate plastic waste in the ocean is largely ineffective at spotting plastic on beaches.

Geospatial scientists have found a way to detect plastic waste on remote beaches, bringing us closer to global monitoring options. Credit: RMIT

Much of the problem is that plastic can be mistaken for patches of sand when viewed from space. The Beached Plastic Debris Index (BPDI) developed by Dr. Guffogg and her colleagues circumvents this by employing a spectral index – a mathematical formula that analyzes patterns of reflected light. The BPDI is specially designed to map plastic debris in coastal areas using high-definition data from the WorldView-3 satellite, a commercial Earth observation satellite (owned by Maxar Technologies) that has been in operation since 2014.

Thanks to their efforts, scientists now have an effective way to monitor plastic on beaches, which could assist in clean-up operations. As part of the remote sensing team at RMIT, Dr. Guffogg and her colleagues have developed similar tools for monitoring forests and mapping bushfires from space. To validate the BPDI, the team field-tested it by placing 14 plastic targets on a beach in southern Gippsland, about 200 km (125 mi) southeast of Melbourne. Each target was made of a different type of plastic and measured two square meters (21.5 square feet) – smaller than the satellite’s pixel size of about three square meters.

The resulting images were compared to three other indices, two designed for detecting plastics on land and one for detecting plastics in aquatic settings. The BPDI outperformed all three as the others struggled to differentiate between plastics and sand or misclassified shadows and water as plastic. As study author Dr. Mariela Soto-Berelov explained, this makes the BPDI far more useful for environments where water and plastic-contaminated pixels are likely to coexist.  

“This is incredibly exciting, as up to now we have not had a tool for detecting plastics in coastal environments from space. The beauty of satellite imagery is that it can capture large and remote areas at regular intervals. Detection is a key step needed for understanding where plastic debris is accumulating and planning clean-up operations, which aligns with several Sustainable Development Goals, such as Protecting Seas and Oceans.”  

The next step is to test the BPDI tool in real-life scenarios, which will consist of the team partnering with various organizations dedicated to monitoring and addressing the plastic waste problem.

Further Reading: RMIT, Marine Pollution Bulletin

The post Plastic Waste on our Beaches Now Visible from Space, Says New Study appeared first on Universe Today.

Space-based telescopes are remarkable. Their view isn’t obscured by the weather in our atmosphere, and so they can capture incredibly detailed images of the heavens. Unfortunately, they are quite limited in mirror size. As amazing as the James Webb Space Telescope is, its primary mirror is only 6.5 meters in diameter. Even then, the mirror had to have foldable components to fit into the launch rocket. In contrast, the Extremely Large Telescope currently under construction in northern Chile will have a mirror more than 39 meters across. If only we could launch such a large mirror into space! A new study looks at how that might be done.

As the study points out, when it comes to telescope mirrors, all you really need is a reflective surface. It doesn’t need to be coated onto a thick piece of glass, nor does it need a big, rigid support structure. All that is just needed to hold the shape of the mirror against its own weight. As far as starlight is concerned, the shiny surface is all that matters. So why not just use a thin sheet of reflective material? You could just roll it up and put it in your launch vehicle. We could, for example, easily launch a 40-meter roll of aluminum foil into space.

Of course, things aren’t quite that simple. You would still need to unroll your membrane telescope back into its proper shape. You would also need a detector to focus the image upon, and you’d need a way to keep that detector in the correct alignment with the broadsheet mirror. In principle, you could do that with a thin support structure, which wouldn’t add an excessive bulk to your telescope. But even if we assume all of those engineering problems could be solved, you’d still have a problem. Even in the vacuum of space, the shape of such a thin mirror would deform over time. Solving this problem is the main focus of this new paper.

Once launched into space and unfurled, the membrane mirror wouldn’t deform significantly. But to capture sharp images, the mirror would have to maintain focus on the order of visible light. When the Hubble was launched, its mirror shape was off by less than the thickness of a human hair, and it took correcting lenses and an entire shuttle mission to fix. Any shifts on that scale would render our membrane telescope useless. So the authors look to a well-used trick of astronomers known as adaptive optics.

How radiative adaptive optics might work. Credit: Rabien, et al

Adaptive optics is used on large ground-based telescopes as a way to correct for atmospheric distortion. Actuators behind the mirror distort the mirror’s shape in real time to counteract the twinkles of the atmosphere. Essentially, it makes the shape of the mirror imperfect to account for our imperfect view of the sky. A similar trick could be used for a membrane telescope, but if we had to launch a complex actuator system for the mirror, we might as well go back to launching rigid telescopes. But what if we simply use laser projection instead?

By shining a laser projection onto the mirror, we could alter its shape through radiative recoil. Since it is simply a thin membrane, the shape would be significant enough to create optical corrections, and it could be modified in real time to maintain the mirror’s focus. The authors call this technique radiative adaptive optics, and through a series of lab experiments have demonstrated that it could work.

Doing this in deep space is much more complicated than doing it in the lab, but the work shows the approach is worth exploring. Perhaps in the coming decades we might build an entire array of such telescopes, which would allow us to see details in the distant heavens we can now only imagine.

Reference: Rabien, S., et al. “Membrane space telescope: active surface control with radiative adaptive optics.” Space Telescopes and Instrumentation 2024: Optical, Infrared, and Millimeter Wave. Vol. 13092. SPIE, 2024.

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Voyager 1 was launched waaaaaay back in 1977. I would have been 4 years old then! It’s an incredible achievement that technology that was built THAT long ago is still working. Yet here we are in 2024, Voyager 1 and 2 are getting older. Earlier this week, NASA had to turn off one of the radio transmitters on Voyager 1. This forced communication to rely upon the low-power radio. Alas technology around 50 years old does sometimes glitch and this was the result of a command to turn on a heater. The result was that Voyager 1 tripped into fault protection mode and switch communications! Oops. 

Voyager 1 is a NASA space probe launched on September 5, 1977, as part of the Voyager program to study the outer planets and beyond. Initially, Voyager 1’s mission focused on flybys of Jupiter and Saturn, capturing incredible images before traveling outward. In 2012, it became the first human-made object to enter interstellar space, crossing the heliopause—the boundary between the influence of the Sun and interstellar space. It now continues to  to send data back to Earth from over 22 billion km  away, helping scientists learn about the interstellar medium. There is also a “Golden Record” onboard which contains sounds and images of life on Earth, Voyager 1 serves as a time capsule, intended to articulate the story of our world to any alien civilizations that may encounter it.

The Ringed Planet Saturn

Just a few days ago on 24 October, NASA had to reconnect to Voyager 1 on its outward journey because one of its radio transmitters had been turned off! Alien intervention perhaps! Exciting though that would be, alas not. 

The transmitter seems to have been turned off as a result of one of the spacecraft fault protection systems. Any time there is an issue with onboard systems the computer will flip the systems into protection mode to protect any further damage. If the spacecraft draws too much power from the batteries, the same system will turn off less critical systems to conserve power. When the fault protection system kicks in, it’s then the job of engineers on the ground fixing the fault.

Artist rendition of Voyager 1 entering interstellar space. (Credit: NASA/JPL-Caltech)

There are challenges here though. Due to the immense distance to Voyager 1, now about 24 billion km away, any communications to or from takes almost 23 hours to arrive. A request for data for example means a delay of 46 hours before the request arrives and the data returned! Undaunted, the team sent commands to Voyager 1 on the 16 October to turn on a heater but, whilst the probe should have had enough power, the command triggered the system to turn off a radio transmitter to conserve power. This was discovered on 18 October when the Deep Space Network was no longer able to detect the usual ping from the spacecraft. 

The engineers correctly identified the likely cause of the problem and found Voyager pinging away on a different frequency using the alternate radio transmitte. This one hadn’t been used since the early 19080’s! With the fault identified, the team did not switch immediately back to the original transmitter just yet in case the fault triggered again. Instead,they are now working to understand the fault before switching back. 

Until then, Voyager 1 will continue to communicate with Earth using the lower power transmitter as it continues its exploration out into interstellar space. 

Source : After Pause, NASA’s Voyager 1 Communicating With Mission Team

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Perhaps the greatest tool astronomers have is the ability to look backward in time. Since starlight takes time to reach us, astronomers can observe the history of the cosmos by capturing the light of distant galaxies. This is why observatories such as the James Webb Space Telescope (JWST) are so useful. With it, we can study in detail how galaxies formed and evolved. We are now at the point where our observations allow us to confirm long-standing galactic models, as a recent study shows.

This particular model concerns how galaxies become chemically enriched. In the early universe, there was mostly just hydrogen and helium, so the first stars were massive creatures with no planets. They died quickly and spewed heavier elements, from which more complex stars and planets could form. Each generation adds more elements to the mix. But as a galaxy nurtures a menagerie of stars from blue supergiants to red dwarfs, which stars play the greatest role in chemical enrichment?

One model argues that it is the most massive stars. This makes sense because giant stars explode as supernovae when they die. They toss their enriched outer layers deep into space, allowing the material to mix within great molecular clouds from which new stars can form. But about 20 years ago, another model argued that smaller, more sunlike stars played a greater role.

The Cat’s Eye nebula is a remnant of an AGB star. Credit: ESA, NASA, HEIC and the Hubble Heritage Team, STScI/AURA

Stars like the Sun don’t die in powerful explosions. Billions of years from now, the Sun will swell into a red giant star. In a desperate attempt to keep burning, the core of a sun-like star heats up significantly to fuse helium, and its diffuse outer layers swell. On the Hertzsprung-Russell diagram, they are known as asymptotic giant branch (AGB) stars. While each AGB star might toss less material into interstellar space, they are far more common than giant stars. So, the model argues, AGB stars play a greater role in the enrichment of galaxies.

Both models have their strengths, but proving the AGB model over the giant star model would prove difficult. It’s easy to observe supernovae in galaxies billions of light years away. Not so much with AGB stars. Thanks to the JWST, we can now test the AGB model.

Using JWST the study looked at the spectra of three young galaxies. Since the Webb’s NIRSpec camera can capture high-resolution infrared spectra, the team could see not just the presence of certain elements but their relative abundance. They found a strong presence of carbon and oxygen bands, which is common for AGB remnants, but also the presence of more rare elements such as vanadium and zirconium. Taken altogether, this points to a type of AGB star known as thermally pulsing AGBs, or TP-AGBs.

Many red giant stars enter a pulsing phase at the end of their lives. The hot core swells the outer layers, things cool down a bit, and gravity compresses the star a bit, which heats the core, and the whole process starts over. This study indicates that TP-AGBs are particularly efficient at enriching galaxies, thus confirming the 20-year-old model.

Reference: Lu, Shiying, et al. “Strong spectral features from asymptotic giant branch stars in distant quiescent galaxies.” Nature Astronomy (2024): 1-13.

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Neutron stars are extraordinarily dense objects, the densest in the Universe. They pack a lot of matter into a small space and can squeeze several solar masses into a radius of 20 km. When two neutron stars collide, they release an enormous amount of energy as a kilonova.

That energy tears atoms apart into a plasma of detached electrons and atomic nuclei, reminiscent of the early Universe after the Big Bang.

Even though kilonova are extraordinarily energetic, they’re difficult to observe and study because they’re transient and fade quickly. The first conclusive kilonova observation was in 2017, and the event is named AT2017gfo. AT stands for Astronomical Transient, followed by the year it was observed, followed by a sequence of three letters that are assigned to uniquely identify the event.

New research into AT2017gfo has uncovered more details of this energetic event. The research is “Emergence hour-by-hour of r-process features in the kilonova AT2017gfo.” It’s published in the journal Astronomy and Astrophysics, and the lead author is Albert Sneppen from the Cosmic Dawn Center (DAWN) and the Niels Bohr Institute, both in Copenhagen, Denmark.

A kilonova explosion creates a spherical ball of plasma that expands outward, similar to the conditions shortly after the Big Bang. Plasma is made up of ions and electrons, and the intense heat prevents them from combining into atoms.

However, as the plasma cools, atoms form via nucleosynthesis, and scientists are intensely interested in this process. There are three types of nucleosynthesis: slow neutron capture (s-process), proton process (p-process), and rapid neutron capture (r-process). Kilonovae form atoms through the r-process and are known for forming heavier elements, including gold, platinum, and uranium. Some of the atoms they form are radioactive and begin to decay immediately, and this releases the energy that makes a kilonova so luminous.

This study represents the first time astronomers have watched atoms being created in a kilonova.

“For the first time we see the creation of atoms.”

Rasmus Damgaard, co-author, PhD student at Cosmic DAWN Center

Things happen rapidly in a kilonova, and no single telescope on Earth can watch as it plays out because the Earth’s rotation removes it from view.

“This astrophysical explosion develops dramatically hour by hour, so no single telescope can follow its entire story. The viewing angle of the individual telescopes to the event is blocked by the rotation of the Earth,” explained lead author Sneppen.

This research is based on multiple ground telescopes that each took their turn watching the kilonova as Earth rotated. The Hubble also contributed observations from its perch in low-Earth orbit.

“But by combining the existing measurements from Australia, South Africa and The Hubble Space Telescope, we can follow its development in great detail,” Sneppen said. “We show that the whole shows more than the sum of the individual sets of data.”

As the plasma cools, atoms start to form. This is the same thing that happened in the Universe after the Big Bang. As the Universe expanded and cooled and atoms formed, light was able to travel freely because there were no free electrons to stop it. AT2017gfo produced

The research is based on spectra collected from 0.5 to 9.4 days after the merger. The observations focused on optical and near-infrared (NIR) wavelengths because, in the first few days after the merger, the ejecta is opaque to shorter wavelengths like X-rays and UV. Optical and NIR are like open windows into the ejecta. They can observe the rich spectra of newly-formed elements, which are a critical part of kilonovae.

This figure from the research shows how different telescopes contributed to the observations of AT2017gfo. Image Credit: Sneppen et al. 2024.

The P Cygni spectral line is also important in this research. It indicates that a star, or in this case, a kilonova, has an expanding shell of gas around it. It’s both an emission line and an absorption line and has powerful diagnostic capabilities. Together, they reveal velocity, density, temperature, ionization, and direction of flow.

Strontium plays a strong role in this research and in kilonovae. It produces strong emission and absorption features in Optical/NIR wavelengths, which also reveal the presence of other newly formed elements. These spectral lines do more than reveal the presence of different elements. Along with P Cygni, they’re used to determine the velocity of the ejecta, the velocity structures in the ejecta, and the temperature conditions and ionization states.

The spectra from AT2017gfo are complex and anything but straightforward. However, in all that light data, the researchers say they’ve identified elements being synthesized, including Tellurium, Lanthanum, Cesium, and Yttrium.

“We can now see the moment where atomic nuclei and electrons are uniting in the afterglow. For the first time we see the creation of atoms, we can measure the temperature of the matter and see the micro physics in this remote explosion. It is like admiring the cosmic background radiation surrounding us from all sides, but here, we get to see everything from the outside. We see before, during and after the moment of birth of the atoms,” says Rasmus Damgaard, PhD student at Cosmic DAWN Center and co-author of the study.

“The matter expands so fast and gains in size so rapidly, to the extent where it takes hours for the light to travel across the explosion. This is why, just by observing the remote end of the fireball, we can see further back in the history of the explosion,” said Kasper Heintz, co-author and assistant professor at the Niels Bohr Institute.

The kilonova produced about 16,000 Earth masses of heavy elements, including 10 Earth masses of the elements gold and platinum.

Neutron star mergers also create black holes, and AT2017gfo created the smallest one ever observed, though there’s some doubt. The gravitational wave GW170817 is associated with the kilonova and was detected by LIGO in August 2017. It was the first time a GW event was seen in conjunction with its electromagnetic counterpart. Taken together, the GW data and other observations suggest that a black hole was created, but overall, there’s uncertainty. Some researchers think a magnetar may be involved.

This artist’s illustration shows a neutron star collision that, in addition to the radioactive fire cloud, leaves behind a black hole and jets of fast-moving material from its poles. Illustration: O.S. SALAFIA, G. GHIRLANDA, CXC/NASA, GSFC, B. WILLIAMS ET AL

Kilonovae are complex objects. They’re like mini-laboratories where scientists can study extreme nuclear physics. Kilonovae are important contributors of heavy elements in the Universe, and researchers are keen to model and understand how elements are created in these environments.

The post The Aftermath of a Neutron Star Collision Resembles the Conditions in the Early Universe appeared first on Universe Today.

Think of the Moon and most people will imagine a barren world pockmarked with craters. The same is likely true of Mars albeit more red in colour than grey! The Earth too has had its fair share of craters, some of them large but most of the evidence has been eroded by centuries of weathering. Surprisingly perhaps, Venus, the second planet from the Sun does not have the same weathering processes as we have on Earth yet there are signs of impact craters, but no large impact basins! A team of astronomers now think they have secured a new view on the hottest planet in the Solar System and revealed the missing impact sites. 

Venus is the second planet from the Sun and, whilst it’s often called Earth’s sister planet, the reality is really they differ in many ways. The term comes from similarities in size and composition yet the conditions on Venus are far more hostile. Surface temperatures far exceed the boiling point of water, the dense atmosphere exerts a pressure on the surface equivalent to being 3,000 feet under water and there is sulphuric acid rain in the atmosphere! Most definitely not a nice place to head to for your next vacation. 

Venus

If you were to stand on the surface of Venus you would see beautifully formed craters. Looking down on the planet from orbit you would see none due to the thick, dense atmosphere. Yet if you could gaze through the obscuring clouds you would see a distinct lack of larger impact basins of the sort we are familiar with on the Moon. Now, a team of researchers mostly from the Planetary Science Institute believe they solve the mystery of the missing craters. 

The Moon. Credit: NASA

They have mapped a region of Venus known as Haastte-baad Tessera using radar technology and the results were rather surprising. The region is thought to be one of the oldest surfaces on Venus and is classed as tessera terrain. This type of feature is complex and is characterised by rough, intersecting ridges to create a tile like pattern thought to be the result of a thin but strong layer of material forming over a weak layer which can flow and convect energy just like boiling water. Images from the area in question reveal a set of concentric rings over 1,400 km across at their widest. The team propose that the feature is the result of two back-to-back impact events. “Think of pea soup with a scum forming on top,” said Vicki Hansen,  Planetary Science Institute Senior Scientist. 

Obviously there is no pea soup on Venus but instead, the thin crust layer formed upon a layer of molten lava. Venus of today has a thick outer shell called a lithosphere which is about 112 km thick but when Venus was younger, its thought it was just 9km thick! If an impactor struck the hot young Venus then it’s very likely it would have fractured the lithosphere allowing molten lava to seep through and eventually solidify to create the tesserae we see today. 

Confusing things slightly however is that features like this have been seen on top of flat, raised plateaus where the lithosphere is likely much thicker. The researchers have an answer for this though, “When you have vast amounts of partial melt in the mantle that rushes to the surface, what gets left behind is something called residuum. Solid residuum is much stronger than the adjacent mantle, which did not experience partial melting.” said Hansen. “What may be surprising is that the solid residuum is also lower density than all the mantle around it. So, it’s stronger, but it’s also buoyant. You basically have an air mattress sitting in the mantle beneath your lava pond, and it’s just going to rise up and raise that tessera terrain.”

The features found by the time seem to show that two impact events happened one after the other with the first creating the build up of lava and the second creating the ring structure seen today. 

Source : Impact craters were hiding in plain sight, say researchers with a new view of Venus

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In a few years, as part of the Artemis Program, NASA will send the “first woman and first person of color” to the lunar surface. This will be the first time astronauts have set foot on the Moon since the Apollo 17 mission in 1972. This will be followed by the creation of permanent infrastructure that will allow for regular missions to the surface (once a year) and a “sustained program of lunar exploration and development.” This will require spacecraft making regular trips between the Earth and Moon to deliver crews, vehicles, and payloads.

In a recent NASA-supported study, a team of researchers at the University of Illinois Urbana-Champaign investigated a new method of sending spacecraft to the Moon. It is known as “multimode propulsion,” a method that integrates a high-thrust chemical mode and a low-thrust electric mode – while using the same propellant. This system has several advantages over other forms of propulsion, not the least of which include being lighter and more cost-effective. With a little luck, NASA could rely on multimode propulsion-equipped spacecraft to achieve many of its Artemis objectives.

The paper describing their investigation, “Indirect optimal control techniques for multimode propulsion mission design,” was recently published in Acta Astronautica. The research was led by Bryan C. Cline, a doctoral student in the Department of Aerospace Engineering at the University of Illinois Urbana-Champaign. He was joined by fellow aerospace engineer and PhD Candidate Alex Pascarella, and Robyn M. Woollands and Joshua L. Rovey – an assistant professor and professor with the Grainger College of Engineering (Aerospace Engineering).

Artist’s impression of the ESA LISA Pathfinder mission. Credit: ESA–C.Carreau

To break it down, a multimode thruster relies on a single chemical monopropellant – like hydrazine or Advanced Spacecraft Energetic Non-Toxic (ASCENT) propellant – to power chemical thrusters and an electrospray thruster (aka. colloid thruster). The latter element relies on a process known as electrospray ionization (ESI), where charged liquid droplets are produced and accelerated by a static electric field. Electrospray thrusters were first used in space aboard the ESA’s LISA Pathfinder mission to demonstrate disturbance reduction.

By developing a system that relies on both that can switch as needed, satellites will be able to perform propulsive manuevers using less propellant (aka. minimum-fuel transfers). As Cline said in a Grainger College of Engineering press release:

“Multimode propulsion systems also expand the performance envelope. We describe them as flexible and adaptable. I can choose a high-thrust chemical mode to get someplace fast and a low-thrust electrospray to make smaller maneuvers to stay in the desired orbit. Having multiple modes available has the potential to reduce fuel consumption or reduce time to complete your mission objective.”

The team’s investigation follows a similar study conducted by Cline and researchers from NASA’s Goddard Spaceflight Center and the aerospace advisory company Space Exploration Engineering, LLC. In a separate paper, “Lunar SmallSat Missions with Chemical-Electrospray Multimode Propulsion,” they considered the advantages of multimode propulsion against all-chemical and all-electric approaches for four design reference missions (DRMs) provided by NASA. For this latest investigation, Cline and his colleagues used a standard 12-unit CubeSat to execute these four mission profiles.

.Earth–Mars minimum-fuel trajectory when the CubeSat is coasting, as well as in mode 1-low thrust and mode 2-high thrust. Credit: UIU-C

“We showed for the first time the feasibility of using multimode propulsion in NASA-relevant lunar missions, particularly with CubeSats,” said Cline. “Other studies used arbitrary problems, which is a great starting point. Ours is the first high-fidelity analysis of multimode mission design for NASA-relevant lunar missions.”

Multimode propulsion is similar in some respects to hybrid propulsion, where two propulsion systems are combined to achieve optimal thrust. A good example of this (though still unrealized) is bimodal nuclear propulsion, where a spacecraft relies on a nuclear-thermal propulsion (NTP) and nuclear-electric propulsion (NEC) system. While an NTP system relies on a nuclear reactor to heat hydrogen or deuterium propellant and can achieve a high rate of acceleration (delta-v), an NEC system uses the reactor to power an ion engine that offers a consistent level of thrust.

A key advantage multimode propulsion has over a hybrid system is a drastic reduction in the dry mass of the spacecraft. Whereas hybrid propulsion systems require two different propellants (and hence, two separate fuel tanks), bimodal propulsion requires only one. This not only saves on the mass and volume of the spacecraft, but makes them cheaper to launch. “I can choose to use high-thrust at any time and low-thrust at any time, and it doesn’t matter what I did in the past,” said Cline. “With a hybrid system, when one tank is empty, I can’t choose that option.”

To complete each of the design reference missions for this project, the team made all decisions manually – i.e., when to use high-thrust and low-thrust. As a result, the trajectories weren’t optimal. This led Cline to develop an algorithm after completing the project that automatically selects which mode would lead to an optimal trajectory. This allowed Cline and his team to solve a simple two-dimensional transfer between Earth and Mars and a three-dimensional transfer to geostationary orbit that minimizes fuel consumption. As Cline explained:

“This was an entirely different beast where the focus was on the development of the method, rather than the specific results shown in the paper. We developed the first indirect optimal control technique specifically for multimode mission design. As a result, we can develop transfers that obey the laws of physics while achieving a specific objective such as minimizing fuel consumption or transfer time.”

“We showed the method works on a mission that’s relevant to the scientific community. Now you can use it to solve all kinds of mission design problems. The math is agnostic to the specific mission. And because the method utilizes variational calculus, what we call an indirect optimal control technique, it guarantees that you’ll get at least a locally optimal solution.”

Artist rendering of an Artemis astronaut exploring the Moon’s surface during a future mission. Credit: NASA

The research is part of a project led by Professor Rovey and a multi-institutional team known as the Joint Advanced Propulsion Institute (JANUS). Their work is funded by NASA as part of a new Space and Technology Research Institute (STRI) initiative. Rovey is responsible for leading the Diagnostics and Fundamental Studies team, along with Dr. John D. Williams, a Professor of Mechanical Engineering and the Director of the Electric Propulsion & Plasma Engineering Laboratory at Colorado State University (CSU).

As Cline indicated, their work into multimode propulsion could revolutionize how small spacecraft travel between Earth and the Moon, Mars, and other celestial bodies:

“It’s an emerging technology because it’s still being developed on the hardware side. It’s enabling in that we can accomplish all kinds of missions we wouldn’t be able to do without it. And it’s enhancing because if you’ve got a given mission concept, you can do more with multimode propulsion. You’ve got more flexibility. You’ve got more adaptability.

“I think this is an exciting time to work on multimode propulsion, both from a hardware perspective, but also from a mission design perspective. We’re developing tools and techniques to take this technology from something we test in the basement of Talbot Lab and turn it into something that can have a real impact on the space community.”

Further ReadingL University of Illinois Urbana-Champaign, Acta Astronautica

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China has a fabulously rich history when it comes to space travel and was among the first to experiment in rocket technology. The invention of the rocket is often attributed to the Sung Dynasty (AD 960-1279.) Since then, China has been keen to develop and build its own space industry. The Chinese National Space Administration has already successfully landed probes on the Moon but is preparing for their first human landers. Chinese astronauts are sometimes known as taikonauts and CNSA has just confirmed their fourth batch of taikonauts are set for a lunar landing. 

The Chinese National Space Administration (CNSA) is China’s equivalent to NASA. It was founded in 1993 to oversee the country’s space aspirations. Amazing results have been achieved over the last twenty years including the landmark Chang’e lunar missions. In 2019 Chang’e-4 landed on the far side of the Moon, the first lunar lander to do so and in 2021 became the third country to land a rover on Mars. In 2021 the first modules for CNSA’s Tiangong space station were launched, it’s now operational and working with other space agencies, is working on a number of scientific research projects. 

China has announced that it successfully completed its latest selection process in May. The CNSA are striving to expand their team of taikonauts. Ten were chosen from all the applicants including 8 experienced space pilots and two payload specialists. The team will now begin their program of training in August covering over 200 subject areas designed to prepare them for future missions to the Moon and other Chinese space initiatives. 

The training covers an extensive range of skills It will include training for living and working in microgravity, to learn about physical and mental health in space and specialist training in extravehicular activities. They will also learn maintenance techniques for advanced spacecraft systems and in hands-on training for undertaking experiments in microgravity. 

On her 2007 mission aboard the International Space Station, NASA astronaut Peggy Whitson, Expedition 16 commander, worked on the Capillary Flow Experiment (CFE), which observes the flow of fluid, in particular capillary phenomena, in microgravity. Credits: NASA

The program is designed to expand and fine tune the skills of the taikonauts in preparation for future crewed lunar missions. Specialist training for lunar landings include piloting spacecraft under different gravitational conditions, manoeuvring lunar rovers, training in celestial navigation and stellar identification. 

Not only will they learn about space operations but they will have to learn skills to support scientific objectives too. This will include how to conduct geological surveys and how to operate tools and manoeuvre in the micro-gravitational environments. 

Source : China’s fourth batch of taikonauts set for lunar landings

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It was 1969 that humans first set foot on the Moon. Back then, the Apollo mission was the focus of the attempts to land on the Moon but now, over 50 years on, it looks like we are set to head back. The Artemis project is the program that hopes to take us back to the Moon again and it’s going from strength to strength. The plan is to get humans back on the Moon by 2025 as part of Artemis III. As a prelude to this, NASA is now turning its attention to the possible landing sites. 

The Artemis Project is NASA’s program aimed at returning humans to the Moon and establishing a permanent base there. Ultimately with a view to paving the way for missions to Mars. With the first launch in 2017, Artemis intends to land “the first woman and the next man” on the lunar surface by 2025.  The program began with Artemis I and an uncrewed mission which orbited the Moon. Arte is II will take astronauts on an orbit of the Moon and finally Artemis III will land humans back on the Moon by 2025. At the heart of the program is the giant Space Launch System (SLS) rocket and the Orion spacecraft. 

NASA’s Space Launch System rocket carrying the Orion spacecraft launches on the Artemis I flight test, Wednesday, Nov. 16, 2022, from Launch Complex 39B at NASA’s Kennedy Space Center in Florida. Credit: NASA/Joel Kowsky.

As the plans ramp up for the first crewed landing, NASA are now analysing possible landing sites and have identified nine potential spots. They are all near the South Pole of the Moon and will provide Artemis III with landing sites near to potentially useful resources. Further investigations will be required to further assess them for their suitability. 

The team working upon the analysis is the Cross Agency Site Selection Analysis team and they will work with other science and industry partners. The teams will explore each possible site for science value and suitability for the mission including the availability of water ice. The final list so far, and in no particular order, are;

• Peak near Cabeus B
• Haworth
• Malapert Massif
• Mons Mouton Plateau
• Mons Mouton
• Nobile Rim 1
• Nobile Rim 2
• de Gerlache Rim 2
• Slater Plain

The South Polar region was chosen as a region was chosen chiefly because it has water locked up deep in the shadowed craters. The Apollo missions never visited that region of the Moon either so it is a great opportunity for humans to explore this aged region of the lunar surface. To settle on these 9 areas, the team assessed various regions of the south polar region using potential launch window suitability, terrain suitability, communication capability and even lighting levels. The geology team also looked at the landing sites to assess their scientific value 

Apollo 17 astronaut Harrison Schmitt collecting a soil sample, his spacesuit coated with dust. Credit: NASA

NASA will finally settle on the appropriate landing site based upon the decision for the launch date. Once that has been confirmed it will determine the transfer trajectories to the Moon, the orbital paths and the surface environment. 

Source : NASA Provides Update on Artemis III Moon Landing Regions

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The discovery of the accelerated expansion of the Universe has often been attributed to the force known as dark energy. An intriguing new theory was put forward last year to explain this mysterious force; black holes could be the cause of dark energy! The theory goes on to suggest as more black holes form in the Universe, the stronger the pressure from dark energy. A survey from the Dark Energy Spectroscopic Instrument (DESI) seems to support the theory. The data from the first year of operation shows the density of dark energy increases over time and seems to correlate with the number and mass of black holes! 

Cast your mind back 4 billion years to the beginning of the Universe. Just after the Big Bang, the moment when the Universe popped into existence, there was a brief period when the Universe expanded faster than the speed of light. Before you argue that nothing can travel faster than the speed of light we are talking of the very fabric of space and time expanding faster than the speed of light. The speed of light limit relates to travel through the fabric of space, not the fabric of space itself! This was the inflationary period. 

This illustration shows the “arrow of time” from the Big Bang to the present cosmological epoch. Credit: NASA

The energy that drove the expansion in the early Universe shared similarities with dark energy, the repulsive force that seems to permeate the Universe and is driving the current day accelerated expansion of the Universe.

What is dark energy though? It is thought to make up around 68% of the Universe and, unlike normal matter and energy seems to have a repulsive force rather than attractive. The repulsive nature was first inferred from observations in the late 1990’s when astronomers deduced the rate of acceleration when observing distant supernova. As to the nature of dark energy, no-one really knows what it is or what it comes from, that is, until now. 

Artist’s illustration of a bright and powerful supernova explosion. (Credit: NASA/CXC/M.Weiss)

A team of researchers from the University of Michigan and other institutions have published a paper in the Journal of Cosmology and Astroparticle Physics. In their paper they propose that black holes are the source of dark energy. Professor Gregory Tarle said ‘Where in the later Universe do we see gravity as strong as it was at the beginning of the Universe?’ The answer, Tarle goes on to describe is the centre of black holes. Tarle and team propose that what happened during the inflation period runs in reverse during the collapse of a massive star. When this happens, the matter could conceivably become dark energy. 

The team have used data from the Dark Energy Spectroscopic Instrument (DESI) which is mounted upon the 4m Mayall telescope at Kitt Peak National Observatory. The instrument is essentially 5,000 computer controlled fibre optics which cover an area of the sky equal to about 8 square degrees. The evidence of dark energy is achieved by studying tens of millions of galaxies. The galaxies are so far way their light takes billions of years to reach us. We can use the information to determine how fast the Universe is expanding with unprecedented precision. 

Stu Harris works on assembling the focal plane for the Dark Energy Spectroscopic Instrument (DESI), which involves hundreds of thousands of parts, at Lawrence Berkeley National Laboratory on Wednesday, 6 December, 2017 in Berkeley, Calif.

The data shows evidence that dark energy has increased with time. This is not perhaps in itself surprising but it seems to accurately mirror the increase in black holes over time too. Now that DESI is operational, more observations are required to hunt down the black holes and try to quantify their growth over time to see if there really is merit in this new exciting hypothesis. 

Source : Evidence mounts for dark energy from black holes

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If there are alien civilizations in the Universe, some of them could be super advanced. So advanced that they can rip apart planets and create vast shells surrounding a star to capture all its energy. These Dyson spheres should be detectable by modern telescopes. Occasionally astronomers find an object that resembles such an alien megastructure, but so far, they’ve all turned out to be natural objects. As best we can tell, there are no Dyson spheres out there.

And when you think about it, building a Dyson sphere is the cosmic endgame of a capitalist dystopia. In the never-ending quest to capture and consume every last bit of energy, your civilization rips worlds asunder, moving heaven and earth to create an orbitally unstable, unlivable engine. If you can traverse light-years and transform planets, why not just move Earth-like planets and moons into a star’s habitable zone and have a nice cluster of comfy planets to live on? If this kind of stellar-punk civilization is out there, could astronomers detect it? This is the question behind a study on the arXiv.

The authors begin by noting that when Freeman Dyson proposed the idea in 1960, our solar system was the only known planetary system. Star systems were thought to be rare at the time, but now we know better. Most stars have planets, and even our solar system has a dozen water-rich moons that could be made habitable with a shift of their orbits and a bit of terraforming. Since this would be much easier than building a Dyson sphere, the authors argue that modified systems should be much more common. The only question is how to detect them.

One way would be to look for planetary systems that don’t seem to have formed naturally. For example, if you find a system with a dozen worlds in a star’s habitable zone and few other planets, that isn’t likely to have happened by chance. Less obvious would be to look for systems that are orbitally unusual. Perhaps the planets have orbital resonances that aren’t stable in the long term, or have unusually perfect orbits. Maybe the chemical composition of some worlds don’t match that of the system as a whole. Anything that stands out might be worth a closer look.

Using lasers to change a planet’s orbit. Credit: Narasimha, et al

Another way would be to look for signs of systems under construction. The authors note that planets could be moved or captured slowly over time using high-power directional lasers to accelerate them. Stray light from those lasers would be visible across light years. If we detect monochromatic laser light coming from a potentially habitable star, it could be aliens building a better home.

It’s not likely that we’ll find this kind of evidence, but the idea is no stranger than those of giant alien megastructures. Besides, it’s fun to think about just how many habitable planets you could pack into a single star system. It turns out to be quite a lot!

Reference: Narasimha, Raghav, Margarita Safonova, and C. Sivaram. “Making Habitable Worlds: Planets Versus Megastructures.” arXiv preprint arXiv:2309.06562 (2023).

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Is there something strange and alien confined deep inside the Earth? Is it trying to break free and escape into the heavens? No, of course not.

But in a new soundscape from the ESA, it sure sounds like it.

About every 450,000 years, Earth’s magnetic poles flip. North becomes south and vice versa in a phenomenon called geomagnetic reversal. This discovery was shocking since the planet’s magnetic field is such a foundational part of our environment. However, these reversals appear to be mostly harmless to life.

Geomagnetic reversals are chaotic events. Though they occur on average about every 450,000 years, there’s no pattern to them. There have been about 183 of them in the last 83 million years, leading us to the 450,000-year number. But the last one was 780,000 years ago, and some say that we’re overdue for the next one.

Sometimes, the events are excursions rather than full reversals. That’s when the field shifts for several hundred years and then returns to its original orientation, like the Laschamps event about 41,000 years ago. In an excursion, the field reverses in Earth’s outer core while its inner core remains unchanged. These happen more frequently than full reversals, but their exact number and timing are more difficult to determine since their effects aren’t global.

The evidence for these reversals and excursions is found in paleomagnetism. Paleomagnetism measures the orientation of magnetic elements like iron in volcanic rock as it cools. By determining the age of the rock, scientists can determine the orientation of Earth’s magnetic field when the rock solidified. The history of Earth’s magnetic reversals is recorded where new magma cools as the seafloor spreads.

Magnetic stripes are the result of reversals of the Earth’s field and seafloor spreading. The new oceanic crust is magnetized as it forms and then moves away from the ridge in both directions. This diagram shows a ridge (a) about 5 million years ago, (b) about 2 million years ago, and (c) in the present. Image Credit: By Chmee2 – derived from File:Oceanic.Stripe.Magnetic.Anomalies.Scheme.gif, Public Domain, https://commons.wikimedia.org/w/index.php?curid=18557170

During these excursions and reversals, the magnetic field’s strength weakens. During the Laschamps event, which lasted several hundred years, the field weakened to only 5% of its normal strength.

Earth’s magnetic fields deflect cosmic rays away from Earth, and at only 5% of its normal strength, the field lets in far more cosmic rays than usual. Cosmic rays are high-energy particles, usually protons or atomic nuclei, that come from the Sun and from objects both inside and outside of the Milky Way and travel at relativistic speeds. When they strike Earth’s atmosphere, they produce showers of secondary particles.

No matter how often they occur or what causes them, scientists are pretty sure that the Laschamps event was the latest excursion, and the European Space Agency decided it would be good if we knew what it sounded like.

The ESA launched its three-satellite Swarm mission in 2013 to study Earth’s magnetic fields. Swarm measures magnetic signals not only from the core but also from the mantle, the oceans, and all the way up to the ionosphere and magnetosphere. Scientists at the Technical University of Denmark and the German Research Centre for Geosciences used Swarm data and data from other sources to create a soundscape of the Laschamps event.

The scientists used recordings of natural sounds, such as rocks falling and wood creaking, and blended them into alien-like sounds that were both familiar and strange. The result sounds Earthly, subterranean, natural, and creepy all at the same time as if some ancient part of the Earth is writhing around inside the planet, which, in a way, it is.

The first version was created in 2022 and was played as a sort of public art installation in Copenhagen. There were 32 speakers, and each one played the sound represented by changes in the magnetic field at 32 locations around the world.

Check out the ESA’s SoundCloud channel, where they post their audio creations.

The post This is What it Sounds Like When the Earth’s Poles Flip appeared first on Universe Today.

In 1978, NASA scientists Donald J. Kessler and Burton G. Cour-Palais proposed a scenario where the density of objects in Low Earth Orbit (LEO) would be high enough that collisions between objects would cause a cascade effect. In short, these collisions would create debris that would result in more collisions, more debris, and so on. This came to be known as the Kessler Syndrome, something astronomers, scientists, and space environmentalists have feared for many decades. In recent years, and with the deployment of more satellites than ever, the warning signs have become undeniable.

Currently, there is an estimated 13,000 metric tons (14,330 US tons) of “space junk” in LEO. With the breakup and another satellite in orbit – the Intelsat 33e satellite – the situation will only get worse. This broadband communications satellite was positioned about 35,000 km (21,750 mi) above the Indian Ocean in a geostationary orbit (GSO). According to initial reports issued on October 20th, the Intelsat 33e satellite experienced a sudden power loss. Hours later, the U.S. Space Forces (USSF) confirmed that the satellite appeared to have broken up into at least 20 pieces.

While there are no confirmed reports about what caused the breakup, this is hardly the first time a satellite broke up in orbit. In recent years, satellites have been lost through accidental collisions, increased solar activity, or deliberate destruction (during tests of anti-satellite technology). What is known is that the Intelsat 33e satellite, manufactured by Boeing and operated by the multinational satellite services provider Intelsat, has suffered several issues since it was launched in August 2016, especially where its propulsion is concerned.

An artist rendering of the Mission Extension Vehicle docked to an Intelsat satellite.
Credit: Northrop Grumman

The first occurred less than a year after the satellite was launched when it reached its desired orbit three months later than anticipated. This delay was reportedly due to an issue with its primary thruster, which is responsible for controlling the satellite’s altitude and acceleration. Another occurred when it performed a special maneuver that ensures satellites can maintain the right altitude (a “station-keeping activity”). During the maneuver, Intelsat 33e burned more fuel than expected, which reduced the time it would spend in orbit by three and a half years.

In addition, another Intelsat satellite of the same model (a Boeing-built EpicNG 702 MP) failed in 2019. However, they are hardly alone regarding satellites breaking up and producing debris. In July, the Russian commercial satellite RESURS-P1 fractured in LEO, creating over 100 pieces of debris that could be tracked (and likely many more that were too small to detect). That same month, the decommissioned Defense Meteorological Satellite Program (DMSP) 5D-2 F8 satellite broke up in orbit.

On August 9th, 2024, the upper stage of a Long March 6A (CZ-6A) rocket fragmented in orbit, creating a cloud of at least 283 pieces of trackable debris. The geomagnetic storm that took place on February 3rd, 2022, coincided with the launch of 49 Starlink satellites, most of which were lost as a result. It is unclear how this latest incident will affect objects in orbit. Still, astronomers are hopeful that studying the resulting debris will provide insight into the growing problem of space junk.

According to the ESA Space Debris Office, an estimated 40500 objects in LEO are larger than 10 cm (3.9 inches) in diameter. Moreover, there are an additional 1.1 million objects measuring 1 and 10 cm (0.39 to 3.9 inches) in diameter and 130 million objects 1 mm to 1 cm (0.039 to 0.39 inches). Based on the Space Debris Office’s estimates, this adds up to more than 13,000 metric tons, consisting of pieces of spent rocket stages, satellites, and other objects launched into orbit since 1957 – when Sputnik-1 became the first artificial satellite launched into orbit.

In a 2009 paper, Kessler declared that the orbital situation had already reached the point of instability. As he wrote:

“Modeling results supported by data from USAF tests, as well as by a number of independent scientists, have concluded that the current debris environment is “unstable”, or above a critical threshold, such that any attempt to achieve a growth-free small debris environment by eliminating sources of past debris will likely fail because fragments from future collisions will be generated faster than atmospheric drag will remove them.”

In accordance with the 1972 Convention of International Liability for Damage Caused by Space Objects, the country that launched a satellite into space is responsible for its breakup and debris. However, this is only in cases where fault can be proven, and it has been enforced only once in the more than 50 years since it was signed. It is unclear if Intelsat will be fined by the Federal Communications Commission (FCC) for this latest incident. Regardless, this latest breakup highlights the need for a more robust framework for mitigating future collisions and addressing space debris.

In particular, tracking technology will need to evolve so that more objects can be tracked. At present, about 36,860 space objects are regularly tracked by Space Surveillance Networks (SSNs) worldwide and maintained in their catalogs. In addition, active measures to safely track and remove debris from LEO are being researched and developed, some of which have already been deployed. Examples include the ADRAS-J satellite, which launched on February 18th, 2024.

Developed by the Tokyo-based company AstroScale, ADRAS-J is the first mission to approach and survey a piece of space debris. The Clearsat-1 satellite is also being developed by the ESA and Swiss startup ClearSpace Today. NASA is also developing the Active Debris Removal Vehicle (ADRV), a lightweight, single-use vehicle that will remove debris with a mass of 1,000–4,000 kg (1.1 to 4.4 U.S. tons) and at an altitude of 200–2,000 km (124 to 1240 mi).

In the meantime, Intelsat continues to investigate the loss of both of its satellites. According to the latest update issued by the company, which was posted on October 21st, 2024:

“We are coordinating with the satellite manufacturer, Boeing, and government agencies to analyze data and observations. A Failure Review Board has been convened to complete a comprehensive analysis of the cause of the anomaly. Since the anomaly, Intelsat has been in active dialogue with affected customers and partners. Migration and service restoration plans are well underway across the Intelsat fleet and third-party satellites.”

Further Reading: Phys.org, Intelsat

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The JWST has found an exoplanet unlike any other. This unique world has an atmosphere almost entirely composed of water vapour. Astronomers have theorized about these types of planets, but this is the first observational confirmation.

The unique planet is GJ 9827 d. It’s about twice as large as Earth and three times as massive, and it orbits a K-type star about 100 light years away. The Kepler Space Telescope first discovered it during its K2 extension. In 2023, astronomers studied it with the Hubble Space Telescope. They detected hints of water vapour and described it as an ocean world.

“This is the first time we’re ever seeing something like this.”

Eshan Raul, University of Wisconsin – Madison

However, the JWST results show that the atmosphere is almost completely comprised of water vapour.

The results are in new research published in The Astrophysical Journal Letters titled “JWST/NIRISS Reveals the Water-rich “Steam World” Atmosphere of GJ 9827 d.” The lead author is Caroline Piaulet-Ghorayeb from the University of Montréal’s Trottier Institute for Research on Exoplanets.

Astronomers have wondered if steam planets can exist. Some thought that life could exist on them in the cooler, higher layers of their atmospheres. Others think it’s extremely unlikely. But there was no evidence to go on until now.

“This is the first time we’re ever seeing something like this,” said Eshan Raul, who analyzed the JWST data of GJ 9827 d as an undergraduate student at the University of Michigan. “To be clear, this planet isn’t hospitable to at least the types of life that we’re familiar with on Earth. The planet appears to be made mostly of hot water vapor, making it something we’re calling a ‘steam world.'”

However, every exoplanet teaches us something. GJ 9827 d and its unique atmosphere will help scientists understand exoplanets better in general.

“If these are real, it really makes you wonder what else could be out there.”

Eshan Raul, University of Wisconsin – Madison

The researchers used transmission spectroscopy to detect the exoplanet’s atmosphere. As the planet passes in front of its star, the atmosphere absorbs certain wavelengths of light in the starlight’s spectrum. Different chemicals absorb different wavelengths and reveal their presence.

The observations show that GJ 9827 d’s atmosphere is more than 31% water vapour by volume and has very high metal enrichment. The observations also show that no hydrogen or helium is escaping.

The exoplanet’s atmosphere may be strange, but in other ways, the planet itself is common. It’s a sub-Neptune, a planet larger than Earth but smaller than Neptune. Sub-Neptunes are the most common type of exoplanet we’ve found in the Milky Way.

This discovery is about more than sub-Neptunes and steam worlds. It’s about one of the key challenges in exoplanet atmospheres: the clouds-metallicity degeneracy.

When astronomers use transmission spectroscopy to examine and characterize an exoplanet’s atmosphere, high metallicity and clouds can produce the same signal. High metallicity can produce smaller spectral features, and clouds can also mute and flatten spectral features. Clouds can also mask the presence of molecular absorbers below the cloud deck. As a result, when scientists see a relatively flat spectrum or muted features, they struggle to determine if they’re seeing a metal-rich atmosphere with intrinsically small features or a low-metallicity atmosphere that’s partially obscured by clouds.

This research has broken the stalemate between clouds and metallicity.

Piaulet-Ghorayeb and her co-authors combined previous Hubble Space Telescope observations of GJ 9827 d with JWST observations. The JWST used its NIRISS (Near-Infrared Imager and Slitless Spectrograph) and SOSS (Single Object Slitless Spectroscopy) to analyze the exoplanet’s atmosphere during two transits. This provided enough wavelength coverage and precision to break the clouds-metallicity degeneracy. This is the first conclusive observation of a high-metallicity and water-rich atmosphere.

“This is a crucial proving step towards detecting atmospheres on habitable exoplanets in the years to come.”

Ryan MacDonald, Astrophysicist, University of Wisconsin This figure from the research shows GJ 9827 d’s two transits observed by the JWST. The broad wavelength coverage and the precision broke the clouds-metallicity degeneracy. Image Credit: Piaulet-Ghorayeb et al. 2024.

Almost all the exoplanet atmospheres that have been characterized are mostly made of the lighter elements hydrogen and helium. These atmospheres are similar to Jupiter and Saturn in our Solar System. They’re nothing like Earth and its life-friendly atmosphere.

“GJ 9827 d is the first planet where we detect an atmosphere rich in heavy molecules like the terrestrial planets of the solar system,” Piaulet-Ghorayeb said. “This is a huge step.”

Though GJ 9827 d isn’t habitable as far as our understanding of life goes, other exoplanets with similar metallicity are desirable targets in the search for life. Now that astronomers have broken the clouds-metallicity degeneracy, it changes our understanding of those planets and scientists’ ability to discern them. It’s all thanks to the JWST and its observing prowess.

Ryan MacDonald is a co-author of the new research and is a U-M astrophysicist and NASA Sagan Fellow. “Even with JWST’s early observations in 2022, researchers were discovering new insights into the atmospheres of distant gas giants,” MacDonald said, referring to the JWST’s spectroscopic characterizations of exoplanet atmospheres.

But those atmospheres were primarily composed of light gases, not heavier metals. These observations take us deeper into the atmospheres of sub-Neptunes. And though they’re the most common type of exoplanet in our galaxy, our Solar System is without one.

“Now we’re finally pushing down into what these mysterious worlds with sizes between Earth and Neptune, for which we don’t have an example in our own solar system, are actually made of,” MacDonald said. “This is a crucial proving step towards detecting atmospheres on habitable exoplanets in the years to come.”

The atmospheric steam didn’t jump out of the JWST observations. JWST produces an enormous amount of data, and to make sense of it, astronomers use modelling tools based on sampling algorithms and machine learning techniques. They typically employ several different models and work with all of the results to arrive at the most likely interpretation of the data.

The process of determining an atmosphere from data is called atmospheric retrieval. A 2023 paper presented a catalogue of 50 different atmospheric retrieval codes used by exoplanet scientists. The lead author of that paper is none other than Ryan MacDonald, a co-author of this new research. MacDonald wrote the software that analyzed and retrieved GJ 9827 d’s atmosphere, and co-author Raul used that software.

Raul generated millions of model atmospheres that matched the JWST observations before settling on the steam world model. In a sense, Raul was the first person to see proof that steam worlds exist.

“It was a very surreal moment,” said Raul, who is now working toward his doctorate at the University of Wisconsin-Madison. “We were searching specifically for water worlds because it was hypothesized that they could exist.”

“If these are real, it really makes you wonder what else could be out there.”

The post Webb Reveals a Steam World Planet Orbiting a Red Dwarf appeared first on Universe Today.

While new rockets and human missions to the Moon are in the press, NASA is quietly thinking through the nuts and bolts of a long-term presence on the Moon. They have already released two white papers about the lunar logistics they’ll require in the future and are now requesting proposals from companies to supply some serious cargo transportation. But this isn’t just for space transport; NASA is also looking for ground transportation on the Moon that can move cargo weighing as much as 2,000 to 6,000 kg (4,400 to 13,000 pounds.)

In a recent press release, NASA asked U.S. industry to submit proposals for logistics ideas and solutions to help the agency land and move cargo on the lunar surface during the upcoming Artemis missions.

“NASA relies on collaborations from diverse partners to develop its exploration architecture,” said Nujoud Merancy, deputy associate administrator, strategy and architecture in the Exploration Systems Development Mission Directorate at NASA Headquarters in Washington. “Studies like this allow the agency to leverage the incredible expertise in the commercial aerospace community.”

In the two white papers, NASA outlined the “gaps” they have lunar logistics and mobility as part of its Moon to Mars architecture.  In the first paper, “Lunar Logistics Drivers, Needs,” NASA said that as the Artemis missions and goals are conceptualized and planned, it is imperative to accurately predict logistics and resupply needs, not only for mission goals but for the very important need of keeping the humans alive and healthy. They need to have a good plan and the ability to transport landed cargo and exploration items from where they are delivered to where they are used.

Graph showing approximate logistics item needs for representative lunar surface missions. Credit: NASA.

“The total amount of logistics items required to keep the crew alive and healthy, to maintain systems, and to perform productive science and utilization can be relatively large,” the authors wrote. “It can also heavily influence the design of the architecture and exploration missions. The architecture must therefore be based on comprehensive, accurate estimates of logistics item needs and include assessment of a suitable logistics sub-architectures to deliver those needs.”

How to provide various things like food, water, air, spare parts, and other similar products required to sustain life, as well as maintain all the various systems and structures are key to having productive science and utilization activities. NASA also expects they will need to move all these supplies around on the Moon, including to the lunar South Pole where they plan to send crews in the future. The paper outlines the importance of accurately predicting logistics resupply needs, as they can heavily influence the overall architecture and design of exploration missions.

An artist’s conception shows NASA’s generic concept for the Lunar Terrain Vehicle. (NASA Illustration)

NASA’ said their current planned lunar mobility elements, such as the Lunar Terrain Vehicle and Pressurized Rover, have a capability limit of about 1,760 pounds (800 kilograms) and will primarily be used to transport astronauts around the lunar surface. However, future missions could include a need to move cargo totaling around 4,400 to 13,000 pounds (2,000 to 6,000 kg). That’s why NASA wants input from companies who have experience in this area.

But to be able to move cargo around to various places on the Moon, NASA first needs to get the supplies to the lunar surface. The second white paper, “Lunar Surface Cargo,” looks at the lunar surface cargo delivery needs, compares those needs with current cargo lander capabilities, and outlines considerations for fulfilling this capability gap. NASA said that access to a diverse fleet of cargo landers would empower a larger lunar exploration footprint, and that a combination of international partnerships and U.S. industry-provided landers could supply the concepts and capabilities to meet this need.

“Given diverse cargo needs of varying size, mass, delivery cadence, and operational needs, a diverse portfolio of cargo lander capabilities will be necessary to achieve NASA’s Moon to Mars Objectives,” the paper says. “Encouraging the development of varied cargo lander concepts and capabilities will be key to establishing a long-term lunar presence for science and exploration.”

Planned and potential cargo to the lunar surface. Credit: NASA

While the request for proposals doesn’t explicitly seek new concepts for landing vehicles, it does ask for integrated assessments of logistics that can include transportation elements.

“We’re looking for industry to offer creative insights that can inform our logistics and mobility strategy,” said Brooke Thornton, industry engagement lead for NASA’s Strategy and Architecture Office. “Ultimately, we’re hoping to grow our awareness of the unique capabilities that are or could become a part of the commercial lunar marketplace.”

Got ideas? Check out NASA’s Request for Proposals.

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Most of the diverse elements in the Universe come from supernovae. We are, quite literally, made of the dust of those long-dead stars and other astrophysical processes. But the details of how it all comes about are something astronomers strive to understand. How do the various isotopes produced by supernovae drive the evolution of planetary systems? Of the various types of supernovae, which play the largest role in creating the elemental abundances we see today? One way astronomers can study these questions is to look at presolar grains.

These are dust grains formed long before the formation of the Sun. Some of them were cast out of older systems as a star fired up its nuclear furnace and cleared its system of dust. Others formed from the remnants of supernovae and stellar collisions. Regardless of its origin, each presolar grain has a unique isotopic fingerprint that tells us its story. For decades, we could only study presolar grains found in meteorites, but missions such as Stardust have captured particles from comets, giving us a richer source for study. Observations from radio telescopes such as ALMA allow astronomers to look at the isotope ratios of these grains at their point of origin. We can now study presolar grains both in the lab and in space. A new study compares the two, focusing on the role of supernovae.

Pair of presolar grains from the Murchison meteorite. Credit: Argonne National Laboratory, Department of Energy

What they found was that the physical gathering of presolar grains will be crucial to understanding their origins. For example, Type II supernovae, also known as [core-collapse supernovae,](https://briankoberlein.com/post/supernovas-tale/) are known to produce Titanium-44, which is an unstable isotope. Through decay processes, this can create an excess of Calcium-44 in presolar grains. But grains cast off from young star systems also have a Calcium-44 excess. In the first case, the grains form with titanium, which then decays to calcium, while in the second case, the grains form with calcium directly. We can’t distinguish between the two just by looking at the isotope ratios. Instead, we have to look at the specific distribution of Calcium-44 within the grain. The team found that using nanoscale secondary ion mass spectrometry (NanoSIMS) they could distinguish the origin of grains found in meteorites. Similar complexities are seen with isotopes of silicon and chromium.

Overall, the study proves that we will need much more study to tease apart the origins of the presolar grains we gather. But as we better understand the grains we gather here on Earth, they should help us unravel a deeper understanding of how elements are forged in the nuclear furnaces of large stars.

Reference: Liu, Nan, et al. “Presolar grains as probes of supernova nucleosynthesis.” arXiv preprint arXiv:2410.19254 (2024).

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Comets have long been seen as omens and portents, and it’s easy to understand why. They first appear as faint smudges of light in the sky, sometimes fading soon after and sometimes becoming brighter than the planets, with a long, glowing tail. They have been observed throughout human history, but it wasn’t until the eighteenth century that astronomers began to predict the return of some comets. Even today, we can’t predict the return of most comets until after they swing through the inner solar system. If such a comet happens to be heading toward Earth, we wouldn’t know about it until too late. But that could change thanks to our observations of meteor showers.

Comets originate from the Oort cloud, the icy remnant of our solar system’s birth that surrounds the Sun as a sphere 100,000 AU in diameter. Whether through a close collision with another Oort object or the nearby passing of a star, some of these distant chunks of ice and rock are sent tumbling toward the inner solar system. They can come from any direction in the sky, and once they dance near the Sun they may not return for hundreds or thousands of years. Any comet with a period longer than 200 years is known as a long-period comet, and these are the hardest to predict.

Most long-period comets pose no threat to Earth. They might appear bright in the evening or morning sky, but their orbits don’t cross Earth’s orbit, so there is no risk of impact. But some long-period comets could pose an impact threat to Earth. We know this in part because we’ve been hit by comets before, and in part because we observe regular meteor showers. Showers such as the Geminids, Perseids, and Orionids are caused by the dusty trails left by comets as they cross Earth’s orbit. In these cases, we have even identified the originating comets as Phaeton, Swift-Tuttle, and Halley’s. But of these, only Swift-Tuttle is a long-period comet (barely) with an orbital period of 257 years.

Illustration of long-period comets and the Oort cloud. Credit: National Astronomical Observatory of Japan

These connections between comets and meteor showers were made by first knowing the comet’s orbit then connecting its path to known showers. In principle, we should be able to do it the other way around. Identify what the path of a meteor shower is, and then use that to search for its long-period comet. As new telescopes such as Rubin Observatory come online, this approach could become a useful tool in the search for impact threats. A recent study on the arXiv shows how this would work.

The team ran simulations of long-period comets ranging from 200 to 4,000 years. They estimated the dust trails these hypothetical comets would produce, then set out to determine if astronomers could use these trails to work backwards to locate the originating comet while it is far from the Sun. In anticipation of having high-resolution sky surveys, the team assumed astronomers could observe them at the anticipated resolution of Rubin Observatory. They found that the orbits of many comets don’t produce showers useful for prediction, but in 17 cases, the showers could be used to identify comets months or years before they would typically be noticed.

The expected orbit for the Aurigid shower. Credit: Hemmelgarn, et al

To prove this point even further, the team also looked at a meteor shower called the ?-Hydrids, a faint shower that appears in early December. The origin of the sigma-Hydrids was not known until the appearance of Comet Nishimura in 2023. Once the orbit was determined, astronomers found a possible connection to the sigma-Hydrid showers. Using known observations of the shower before 2023, the team was able to determine a possible orbit for the comet. They found that with a Rubin-like sky search, astronomers could have found Nishimura eight months before its actual discovery.

Reference: Hemmelgarn, Samantha, et al. “How Meteor Showers Can Guide the Search for Long Period Comets.” arXiv preprint arXiv:2410.02883 (2024).

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Comet C/2023 A3 Tsuchinshan-ATLAS survived perihelion to become a fine dusk object for northern hemisphere observers.

It was an amazing month for astronomy. Not only were we treated to an amazing second solar storm for 2024 that sent aurorae as far south as the Caribbean, but we had a fine naked eye comet: C/2023 A3 Tsuchinshan-ATLAS.

The comet on October 24th, along with the Milky Way over the Sea of Japan as seen from Yuzhno-Morskoy (Nakhodka) Russia. Credit: Filipp Romanov.

Discovered in early 2023, this one actually performed as expected, and topped out as the best comet for 2024. Southern hemisphere observers got a portent of things to come in September, as the comet threaded the dawn skies.

The evolution of the comet post-perihelion through October 25-30th. Credit: Eliot Herman Peril at Perihelion

Then came the big wild card of perihelion. The comet passed just 58.6 million kilometers from the Sun on September 27th. At its maximum, the comet hit nearly -5th magnitude. The dust and plane crossing for the comet were both especially dramatic, as we saw a sharp spiky anti-tail trace out the comet’s orbital trail and appear to pierce the Sun as seen in views from SOHO’s LASCO C2 and C3 imagers.

But would the comet remain bright for its evening encore? This time, luck was on our side, as the comet held at +1st magnitude for about a week, and joined Venus in the dusk sky. As it began its rapid ascent, Comet ‘T-ATLAS’ unfurled its tail about a dozen degrees in length, all while keeping its remarkable anti-tail pointing sunward.

The comet from October 18th, still exhibiting a spiky ‘anti-tail. Credit: Efrain Morales. A ‘Just Point-and-Shoot’ Comet

And then the pictures came pouring in. Comet T-ATLAS was at its photogenic best in early October, as it became an easy target against the starry backdrop. Usually, +2nd magnitude or brighter is the cutoff for catching a comet along with foreground objects. This time, you could actually simply set your smartphone camera to night mode, and capture a decent handheld shot of the comet.

The comet from October 19th, as seen from Ottawa, Canada. Credit: Andrew Symes

Plus, light pollution didn’t seem to faze this comet. We saw shots of the comet from downtown Los Angeles and other urban areas, as folks were treated to the best comet in recent memory since the dawn apparition of F3 NEOWISE in 2020.

Venus, a meteor, an airplane trail, and Comet T-ATLAS from Malaysia. Credit: Shahrin Ahmad.

And to think: the last time a really brilliant comet swung by (C/1995 O1 Hale-Bopp a generation ago in 1997) digital imaging was in its infancy, and film still dominated the market… just think what we might manage to do with such a comet today?

“I drove north for more than three hours, and reached the seashore facing the Sea of Japan after sunset,” says astrophotographer Hisayoshi Kato on Flickr, “It was fortunate that the sky was clear at the site, and I could enjoy the comet sinking into the Sea of Japan (over) the weekend.”

Comet C/2023 A3 Tsuchinshan-ATLAS from October 26th. Credit: Hisayoshi Kato. Awaiting Next ‘Great Comet’

To be sure, it’s only a matter of time before the next ‘Comet of the Century’ makes itself known. Right now, Comet T-ATLAS is still a decent +6th magnitude binocular object in Ophiuchus, outbound on its nearly quarter-of-a-million-year orbit. Alas, a second sungrazer encore for October never came to pass, as Comet C/2024 S1 ATLAS ended its cometary career at perihelion earlier this week…

An amazing parting shot of the comet from October 29th. Credit: Gianluca Masi.

“These days, we all had an extraordinary proof of the splendor of the night sky,” astronomer Gianluca Masi noted in a recent Facebook post. “Comet C/2023 A3 Tsuchinshan-ATLAS is still putting on a show… but the firmament is always a prodigy of emotions and wonders, as those who regularly turn their gaze to the stars know.”

Comet T-ATLAS from downtown Bristol, Tennessee. Credit: Dave Dickinson.

When’s the next one? Well, we do have the promise of a similar comet coming right up in January 2025. C/2024 G3 ATLAS may reach -1st magnitude or brighter near perihelion.

Thanks to everyone that got out there and sent images to the Universe Today Flickr pool. Here’s to the next yet-to-be named bright comet, waiting in the wings to take center stage in the drama of the inner solar system and the skies of Earth.

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One of my favorite paintings is Starry Night by Vincent van Gogh — for obvious astronomical reasons. But another favorite of van Gogh’s works is Lane of Poplars at Sunset. This painting depicts the setting Sun perfectly aligned with a long lane of trees, casting long shadows.

The geometry of the Earth and Sun means that this scene had to be painted on one specific day of the year when the alignment would be possible. An astronomer has now used 19th-century maps to discover where the lane was, and then used astronomical calculations to determine which date the Sun would be in the exact position as the painting. His result? The painting depicts a stretch of road known as Weverstraat in the Dutch town of Nuenen, on November 13 or 14, 1884.

Professor Donald Olson is an astronomer and physics professor emeritus at Texas State University (TSU). He is no stranger to studying van Gogh paintings, as in the past he has uncovered clues to help date three other of the noted painter’s works: Moonrise (July 13, 1889), Road with Cypress and Star (May 1890) and White House at Night (June 1890).

Van Gogh produced more than 2,000 paintings, drawings, and sketches in his lifetime, and many include scenery from The Netherlands, the Dutch master’s home. Olson was originally inspired to determine the date of Lane of Poplars at Sunset because the scene shows something similar to what happens twice a year for New York City’s “Manhattanhenge,” where the setting sun aligns with Manhattan’s east–west streets on dates near May 29 and July 12.  

Manhattanhenge from 42nd Street shot at 8:23 p.m. on July 13, 2006, the building on the right is the Chrysler Building. Photo by Roger Rowlett, via Wikipedia.

The first thing Olson wanted to figure out was where the lane might be.

“If we could identify the lane on 19th-century maps, then we’d be able to establish the compass direction of the road appearing in the artworks,” Olson explained in a news release from TSU. “Next, we could use astronomical calculations to determine the date when the disk of the setting sun aligned as van Gogh portrayed it.”

Olson called in assistance from Louis Verbraak and Ferry Zijp, members of the Eindhoven Weather and Astronomy Club in the Netherlands. After an exhaustive search of maps and correlating historic and recent imagery, the team narrowed it down to three possible streets. Further investigations led them to determine that Weverstraat in Nuenen must be the street, as it contained a long straightaway of 1,200 feet, or 365 meters, more than long enough for the scene painted by van Gogh.

As for determining the date, Olson and team relied on historical information. All of van Gogh’s paintings assigned catalog numbers, in order by dates determined by art historians. Lane of Poplars at Sunset is assigned as F123. The previous painting in the catalog, F122, is called Lane of Poplars in the Autumn, which shows the same scenes with vivid fall colors, while the leaves are almost completely gone from the trees in the sunset depiction. That means the painting had to be done in late fall.

The painting “Line of Poplars in Autumn” by Vincent van Gogh (F122, Nueun 1884).

Art historians have also long depended on van Gogh’s many letters to his brother Theo to help date most of the artist’s work. A total of three letters, written by Vincent during late October and early November of 1884, describe the lovely autumn weather he was experiencing. One letter, dated on or about Oct. 25, 1884, includes a description that matches Lane of Poplars in the Autumn:

“The last thing that I made is a rather large study of a lane of poplars with the yellow autumn leaves, where the Sun makes glittering patches here and there on the fallen leaves on the ground, alternating with the long shadows cast by the trunks. At the end of the road is a peasant cottage, and above it the blue sky between the autumn leaves.”

“White House at Night” by Vincent van Gogh. (F766 Auvers-sur-Oise, 1990).

A subsequent letter dated on or about Nov. 14, 1884, van Gogh indicated that freezing weather forced him to abandon painting outdoors for the rest of the season. Additional letters helped establish a time frame between Nov. 5-Nov. 14 for van Gogh to have painted Lane of Poplars at Sunset. Within this range of dates, planetarium software shows that the sun set in the southwest, in the range of azimuths, or compass direction of a celestial object, between 240° and 244°.

Then using astronomical calculations, Olson and team determined the setting sun would’ve been visible setting over Weverstraat on Nov. 13 or 14, 1884. Historical weather records indicate these dates fall within a five-day span where the area experienced unseasonably clear weather.

Olson said that because van Gogh rarely painted from memory and preferred to have his subject in front of him, Nov. 13 or 14, 1884, are the only possible dates for the creation of Lane of Poplars at Sunset.

“Today, we can still gaze down the same stretch of road where van Gogh walked on a chilly autumn afternoon and ponder how the artist, in his native Netherlands, was already interested in portraying sky phenomena, four years before he began to create his famous starry nights in the south of France,” Olson said.

Read more details about the search at TSU.

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In the summer of ’69, Apollo 11 delivered humans to the surface of the Moon for the first time. Neil Armstrong and Buzz Aldrin spent just over two hours exploring the area near their landing site on foot. Only during Apollo 15, 16, and 17 did astronauts have a vehicle to move around in.

Artemis astronauts on the Moon will have access to a vehicle right away, and NASA is starting to test a prototype.

Momentum is building behind NASA’s Artemis program despite some setbacks. Artemis astronauts will explore the Moon far more thoroughly than the Apollo astronauts did, and technology is behind the improvement. Surface mobility is a key piece of Artemis. In April of 2024, NASA selected three vendors as part of their Lunar Terrain Vehicle Services contract.

NASA engineers at the Johnson Space Center are designing an unpressurized rover prototype known as the Ground Test Unit. It’s a human-rated, unpressurized LTV (Lunar Terrain Vehicle). The unit is being designed and built as a platform to evaluate rover designs being developed by three private companies: Intuitive Machines, Lunar Outpost, and Venturi Astrolab.

Intuitive Machines is known for its IM-1 mission with its Nova-C Lander. They were the first private company to land a spacecraft on the Moon.

Intuitive Machines’ Nova-C lunar lander was the first private spacecraft to land on the Moon. Image Credit: By NASA Marshall Space Flight Center / Intuitive Machines Photo ID: IM_00309., Public Domain, https://commons.wikimedia.org/w/index.php?curid=145130774

Lunar Outpost is known for its Mobile Autonomous Prospecting Platform (MAPP) rover (MAPP) rover. MAPP will be used on Intuitive Machines’ IM-2 and IM-3 missions and will demonstrate aspects of In-Situ Resource Utilization.

Venturi Astrolab is known for developing hyper-deformable wheels and batteries for lunar rovers. They’re also developing their FLEX rover, a larger vehicle designed to be modular to meet different objectives.

The LTV will be used to test the technologies these three companies develop. It’ll be used to evaluate crew compartment design, rover maintenance, science payload, and many other aspects of their rovers.

“The Ground Test Unit will help NASA teams on the ground, test and understand all aspects of rover operations on the lunar surface ahead of Artemis missions,” said Jeff Somers, engineering lead for the Ground Test Unit. “The GTU allows NASA to be a smart buyer, so we are able to test and evaluate rover operations while we work with the LTVS contractors and their hardware.”

Two engineers in suits sit on the prototype during testing at the Johnson Space Center. Image Credit: NASA/Bill Stafford

NASA has some requirements that the three selected companies need to meet. The rover must support two crew members and be able to be operated remotely. It can use multiple control concepts, such as supervised autonomy, different drive modes, and self-levelling.

NASA used its ‘Moon Buggy’ or Lunar Roving Vehicle (LRV) on Apollo 15, 16, and 17 in 1971 and 1972. It could carry 440 kg, including two astronauts, and had a top speed of 18 km/h. Though it provided range and mobility, it never travelled further than walking distance from the landers in case of breakdown. Image Credit: By NASA/Dave Scott; Public Domain, https://commons.wikimedia.org/w/index.php?curid=6057491

By supplying the Ground Test Unit, NASA is making it easier to test the designs from the three companies. It also helps build private sector capacity by enabling testing and iterative design without the separate companies needing to spend money on a GTU. Ground testing also allows for a safer testing environment.

An artist’s illustration of astronauts at the lunar south pole. Image Credit: NASA

When Apollo 11 reached the Moon, it was a civilization-defining moment. There was no reason to explore beyond the landing site since it was as unexplored as the rest of the Moon. But things are much different now.

Thanks to other missions and satellites that orbit the Moon, we have an almost encyclopedic knowledge of our natural satellite compared to the Apollo days. We know what questions we want answered, where we can do the best science, and where useful resources like water ice is. The idea behind Artemis is to go to the Moon and create an infrastructure that will allow us to maintain a presence there.

The Artemis lunar missions will rely on mobility to meet their goals. The LTV will be critical to Artemis’ success by allowing each mission to explore and develop a larger area. NASA intends to use the new rovers starting in Artemis V, which will launch no sooner than 2030.

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