There have been many proposals for building structures on the Moon out of lunar regolith. But here’s an idea sure to resonate with creators, mechanical tinkerers, model builders and the kid inside us all.
What about using actual LEGO bricks?
Researchers ground up a 4.5-billion-year-old meteorite and used the dust to 3D print LEGO-style space bricks. They actually click together like the plastic variety, with so far only one downside: they only come in one color, grey.
Want to see some of these lunar LEGOs? LEGO will showcase the space bricks at some of its stores.
Creating building materials on the Moon or Mars from the material on hand means construction materials don’t have to be transported from Earth. This would be a huge savings in launch costs because less weight would have to be boosted from Earth.
A group of scientists from ESA (European Space Agency) were inspired by LEGO bricks, and with the advances in 3D printing, had the idea to print space bricks and test how they would work for construction.
The only problem was that except for the Moon rocks brought back by the Apollo astronauts – which are highly guarded for scientific study only — there’s not any lunar regolith available on Earth to experiment with.
But meteorite dust is a close cousin to lunar regolith. The ESA team was able to get a meteorite that was discovered in Northwest Africa in 2000 and is about 4.5 billion years old. It is made of metal grains and chondrules, similar to Moon dust.
Inspired by LEGO, ESA scientists have used dust from a meteorite to 3D-print LEGO-style ‘space bricks’ to test out construction ideas for a future Moon base. Credit: The LEGO Group
They mixed the meteorite dust with a some other things, like a polymer called polylactide and regolith simulant and 3D printed bricks that mimic and behave just like LEGO bricks. While they aren’t smooth like regular LEGO bricks, ESA said the space bricks gave ESA’s space engineers the flexibility to build and test a variety of structures using this new material.
“It’s no secret that real-world scientists and engineers sometimes try out ideas with LEGO bricks,” said Emmet Fletcher, Head of ESA’s Branding and Partnerships Office. “ESA’s space bricks are a great way to inspire young people and show them how play and the power of the imagination have an important role in space science, too.”
“Nobody has built a structure on the Moon, so it was great to have the flexibility to try out all kinds of designs and building techniques with our space bricks,” said . ESA Science Officer Aidan Cowley. “It was both fun and useful in scientifically understanding the boundaries of these techniques.”
Below is a list of where the lunar LEGOs will be on display, and the LEGO website has additional details. Hopefully the lunar LEGOs will inspire both children and adults about space and to encourage them to build their own LEGO Moon bases.
USA
The LEGO Store, Mall of America, Bloomington, Minnesota
The LEGO Store, Disney Springs, Florida
The LEGO Store, Water Tower Place, Chicago
The LEGO Store, Disneyland Resort, California
The LEGO Store, 5th Avenue, New York
Canada
The LEGO Store, West Edmonton
UK
The LEGO Store, Leicester Square, London
Germany
The LEGO Store, München Zentrum
The LEGO Store, Cologne
NASA’s InSight Mars Lander faced some challenges during its time on the red planet’s surface. Its mole instrument struggled to penetrate the compacted Martian soil, and the mission eventually ended when its solar panels were covered in dust. But some of its instruments performed well, including SEIS, the Seismic Experiment for Interior Structure.
SEIS gathered Mars seismic data for more than four years, and researchers working with all of that data have determined a new meteorite impact rate for Mars.
SEIS was designed to probe Mars’ interior structure by measuring seismic waves from Marsquakes and impacts. It measured over 1300 seismic events. There’s no way to absolutely measure how many of them were from impacts, but scientists working with the data have narrowed it down.
NASA’s InSight lander placed its seismometer onto Mars on Dec. 19, 2018. SEIS was later covered with a protective shell to shield it from wind. Image Credit: NASA/JPL-Caltech
Their results are in new research published in Nature Astronomy titled “An estimate of the impact rate on Mars from statistics of very-high-frequency marsquakes.” The lead authors are Géraldine Zenhäusern and Natalia Wójcicka, from the Institute of Geophysics, ETH Zurich, and the Department of Earth Science and Engineering, Imperial College, London, respectively.
“This is the first paper of its kind to determine how often meteorites impact the surface of Mars from seismological data.”
Domenico Giardini, Professor of Seismology and Geodynamics at ETH Zurich and co-Principal Investigator for the NASA Mars InSight Mission.
Though SEIS was an effective instrument, it couldn’t always tell what each seismic event was. Only a handful of the events it detected were powerful enough to determine their location. However, six events in close proximity to the InSight lander were confirmed as meteorite impacts because they were correlated with acoustic atmospheric signals that meteors make when they enter Mars’ atmosphere. The six events belong to a larger group called very high-frequency (VF) events.
While the source process for a typical marsquake measuring magnitude 3 takes several seconds, an impact-generated quake takes much less time because of the collision’s hypervelocity. These are the VF events.
During about three years of recording time, InSight and SEIS detected 70 VF events. 59 of them had good distance estimates, and according to the researchers, a handful of them were “higher quality B VF events,” meaning their signal-to-noise ratios are strong. “Although a non-impact origin cannot be definitively excluded for each VF event, we show that the VF class as a whole is plausibly caused by meteorite impacts,” the authors explain in their paper.
This figure from the research shows envelopes of recorded VF quality B events sorted by distance, plotted from 120?seconds before to 1,100?seconds after the event. They’re aligned by their first signal (Pg) arrival. The blue lines are the second signal arrival (Sg.) The six red events are the confirmed impact events, and for those, the black lines show where the “chirp” signal arrives. The chirp signal is a signature of impact events. Image Credit: Zenhäusern, Wójcicka et al. 2024.
This led to a new estimate of Mars’s impact frequencies. The researchers say that between 280 and 360 meteoroids about the size of basketballs strike Mars each year and excavate craters greater than 8 meters (26 ft) in diameter. That’s almost one every day at the upper end. “This rate was about five times higher than the number estimated from orbital imagery alone. Aligned with orbital imagery, our findings demonstrate that seismology is an excellent tool for measuring impact rates,” Zenhäusern said in a press release.
Impact rates on different bodies in the Solar System are one way of understanding the age of their surfaces. Earth’s surface is young because the planet is so geologically active. Earth is also much easier to study in greater detail, for obvious reasons. But for bodies like the Moon and Mars, impact rates can tell us the ages of various surfaces, leading to a more thorough understanding of their history.
Orbital images and models based on preserved lunar craters have been the main tools used by planetary scientists to infer impact rates. The data from the Moon was used to extrapolate Mars’ impact rate. But there are problems with that method. Mars has more powerful gravity and is closer to the source of most meteors, the asteroid belt.
That means more meteoroids strike Mars than the Moon, and that had to be calculated somehow. Conversely, Mars has widespread dust storms that can obscure craters in orbital images, while the lunar surface is largely static. Mars also has different types of surface regions. In some regions, craters stand out; in others, they don’t. Trying to accurately account for that many differences when extrapolating impact rates from the Moon to Mars is challenging.
This work shows that seismometers can be a more reliable way to understand impact rates.
“We estimated crater diameters from the magnitude of all the VF-marsquakes and their distances, then used it to calculate how many craters formed around the InSight lander over the course of a year. We then extrapolated this data to estimate the number of impacts that happen annually on the whole surface of Mars,” Wójcicka explained.
This figure from the research shows crater size and seismic moment for the six confirmed impacts near the InSight lander. Circles show single craters, and triangles show the effective diameter of crater clusters. The vertical error bars reflect the uncertainty in seismic moment magnitude derived using standard error propagation techniques. The horizontal error bars are given by the resolution of HiRISE images used to determine the crater sizes. Image Credit: Zenhäusern, Wójcicka et al. 2024.
“While new craters can best be seen on flat and dusty terrain where they really stand out, this type of terrain covers less than half of the surface of Mars. The sensitive InSight seismometer, however, could hear every single impact within the landers’ range,” said Zenhäusern.
These results extend beyond Mars. Understanding Mars also helps us understand the wider Solar System. “The current meteoroid impact rate on Mars is vital for determining accurate absolute ages of surfaces throughout the Solar System,” the authors write in their paper. Without accurate surface ages, we don’t have an accurate understanding of the Solar System’s history.
Now we know that an 8-metre (26-feet) crater is excavated somewhere on Mars’ surface almost daily, and a 30-metre (98-feet) crater is a monthly occurrence. But it’s about more than just crater size. These hypervelocity impacts create blast zones that dwarf the crater itself. The blast zones can easily be 100 times larger than the crater. So, a better understanding of impact rates can make robotic missions and future human missions safer.
“The higher overall number of impacts and the higher relative number of small ones found in our study show that meteoritic impacts might be a substantial hazard for future explorations of Mars and other planets without a thick atmosphere,” the authors write in their conclusion.
This study is a win for InSight and SEIS and for the researchers who pieced this together.
“This is the first paper of its kind to determine how often meteorites impact the surface of Mars from seismological data – which was a level one mission goal of the Mars InSight Mission,” says Domenico Giardini, Professor of Seismology and Geodynamics at ETH Zurich and co-Principal Investigator for the NASA Mars InSight Mission. “Such data factors into the planning for future missions to Mars.”
As the New Horizons spacecraft continues its epic journey to explore the Kuiper Belt, it has a study partner back here on Earth. The Subaru Telescope on the Big Island of Hawaii is deploying its Hyper Suprime-Cam imager to look at the Kuiper Belt along the spacecraft’s trajectory. Its observations show that the Kuiper Belt extends farther than scientists thought.
The observations support the search for Kuiper Belt objects (KBO) for New Horizons to explore next. So far, Subaru has found many smaller bodies out there. However, none of them are along the spacecraft’s trajectory. In a big surprise to the science teams at Subaru, at least two of those objects orbit beyond 50 astronomical units, which is the current assumed “limit” of the Belt.
If observers continue to find more such objects outside that 50 AU “limit”, it means the Kuiper Belt is bigger than everybody thought. Or it could exist in two parts—a sort of inner and outer Kuiper Belt. Scientists already know that the belt is much dustier than expected, thanks to observations taken with the dust counter onboard New Horizons.
Implications of an Expanded or Two-part Kuiper Belt
Beyond simply expanding the limit of the Kuiper Belt, the Subaru observations have profound implications for our understanding of the solar nebula, according to Fumi Yoshida, who led the research for the Subaru observation team. “Looking outside of the Solar System, a typical planetary disk extends about 100 AU from the host star (100 times the distance between the Earth and the Sun), and the Kuiper Belt, which is estimated to extend about 50 AU, is very compact. Based on this comparison, we think that the primordial solar nebula, from which the Solar System was born, may have extended further out than the present-day Kuiper Belt,” said Yoshida.
Let’s say the primordial disk was quite large. Then it’s possible that undiscovered planetary bodies clipped the outer edge of the Kuiper Belt. If that happened, then it makes sense to search the outer limits of the current Belt to find such a cut-off object. It’s also possible that perhaps that truncation created a second Kuiper Belt beyond the currently known belt. What it’s like is anybody’s guess, although it’s probably dusty and very likely has at least a few larger objects. So, even if there’s nothing along the New Horizons trajectory, using Subaru to study the distribution of objects it has found will help scientists to understand the evolution of the Solar System.
The Hyper Suprime-Cam at the Subaru Telescope in Hawai’i is part of the search for New Horizons flyby targets. It has a special filter to aid in the search. Credit: Subaru Telescope.
Searching for KBOs
Subaru Telescope’s has been searching for more KBOs to explore ever since New Horizons flew past Arrokoth in 2019. The idea is to find additional KBOs along the path of flight. The search focused two Hyper Suprime-Cam fields along the spacecraft’s trajectory through the Belt. The New Horizons team spent about 30 half-nights to find more than 240 outer Solar System objects.
The next step was for a Japanese team to analyze images from those observations. However, they used a different method than the mission team did and found seven new outer Solar System objects. The scientists then analyzed the HSC data with a Moving Object Detection System developed by JAXA. Normally it detects near-Earth asteroids and other space debris. Those types of bodies move very fast, compared to more distant ones. So, looking for very dim, faraway, slow-moving objects was a challenge. That’s because the team had to adjust for the speed of the Kuiper Belt objects. Then they applied some updated image analysis to confirm their findings. Scientists now know the orbits of two of the seven new objects and they’ve been assigned provisional designations by the Minor Planet Center (MPC.
Schematic diagram showing the orbits of the two discovered objects (red: 2020 KJ60, purple: 2020 KK60). The plus symbol represents the Sun; green lines are the orbits of Jupiter, Saturn, Uranus, and Neptune. The numbers on the vertical and horizontal axes represent the distance from the Sun in astronomical units. (1 AU corresponds to the distance between the Sun and the Earth). The black dots represent classical Kuiper Belt objects. These are thought to be a group of icy planetesimals that formed early in Solar System history. The gray dots represent outer Solar System objects with a semi-major axis greater than 30 au. These include objects scattered by Neptune. They extend far out, and many have orbits inclined with respect to the ecliptic plane. The circles and dots in the figure represent their positions on June 1, 2024. Credit: JAXA
Continuing to Search the Kuiper Belt
The discovery of more KBOs in the outer Solar System (along with New Horizons’ continued dust detection activities) tells scientists that there’s more to the Kuiper Belt than anyone expected. The proof will be in continued Subaru observations to detect and confirm more objects “out there.”
“The mission team’s search for Kuiper Belt objects using Hyper Suprime-Cam continues to this day, and a series of papers will be published in the future, mainly by the North American group,” said Yoshida. “This research, the discovery of sources with the potential to expand the Kuiper Belt region using a method developed in Japan and led by Japanese researchers, serves as a precursor to those publications.”
Getting to Proxima Centauri b will take a lot of new technologies, but there are increasingly exciting reasons to do so. Both public and private efforts have started seriously looking at ways to make it happen, but so far, there has been one significant roadblock to the journey – propulsion. To solve that problem, Christopher Limbach, now a professor at the University of Michigan, received a grant from NASA’s Institute for Advanced Concepts (NIAC) to work on a novel type of beamed propulsion that utilizes both a particle beam and a laser to overcome that technology’s biggest weakness.
Let’s first look at why conventional propulsion systems wouldn’t work to get a craft to Proxima b. Conventional rockets are out of the question, as their fuel is too heavy and burns up too quickly to get a probe anywhere near the speed it would need to reach Proxima b. Conventional solar sails also fail because once they are far enough away from the Sun, only a minimum push is applied to them.
Other non-conventional solutions could work, such as nuclear propulsion or ion drives. However, they fall victim to the tyranny of the rocket equation – since they have to carry their fuel, they have to carry more mass to go faster, thereby eliminating much of that benefit.
Fraser explains Breakthrough Starshot, a mission that could potentially utilize the PROCSIMA system.
That leaves beamed propulsion—essentially creating a giant beam in space that continues to push on a spacecraft with a collector on it, which can continue to push the entirety of the time the spacecraft is on its way to its destination. Typically, there are two types of beams used in these systems—particle beams and light beams. However, each has a weakness—diffraction.
Both light and particle beams tend to spread out over long distances, making them much less effective at focusing on a single small object that might be light years away. Even lasers, if allowed to point far away, eventually scatter into unusable light. However, there is a way around this.
Recently, optics research has developed a way of combining particle and laser beams that all but eliminates diffraction and beam spreading when both are used simultaneously. This would allow a beamed propulsion system to continue concentrating its beam on exactly the right place without slowly losing its pushing force as the probe gets further away. Dr. Limbach used this underlying technology to develop what he calls PROCSIMA, a novel propulsion method that used a coherent combined particle and laser beamed propulsion system.
Depiction of the diffraction issues with particle a photon beams, and how a “self-guided” combined beam keeps providing pushing power even to probes that are far away.
Credit – Limbach & Hara
Calculations by Dr. Limbach and his collaborator, Dr. Ken Hara, now a professor at Stanford, show that making a coherent beam that can effectively last to Proxima b while only diffracting out to about 10m is possible, at least in theory. According to their calculations, a 5g probe like the one that the Breakthrough Initiatives project is working on could be pushed up to 10% of the speed of light, allowing it to reach Proxima b in 43 years.
Alternatively, they also calculated that a much larger probe of around 1kg could reach the system in around 57 years. That would allow for a much more exciting payload, even if the probe would zoom through the Proxima Centauri system at a significant fraction of the speed of light.
There is still some work to be done, including developing things like cold atom particle sources and improving the functionality of the beam systems. However, so far, the project hasn’t been supported by another NIAC grant, though Dr. Limbach’s lab at UM continues to work on similar ideas, such as a nanoNewton propulsion system. Development continues on a star shot method to eventually get a probe to another star, and it seems like, for better or worse, beamed propulsion is the way we will get there.
Plate tectonics, oceans, and continents might just be the secret ingredients for complex life on Earth. And if these geological features are rare elsewhere in the universe, then perhaps that explains why we haven’t yet discovered intelligent alien life. New research from American and Swiss Earth scientists suggests that these ingredients represent missing variables in the famous Drake equation, devised more than half a century ago to estimate the chances of finding advanced civilizations in our galaxy. Including these new variables could completely rewrite the probability of detecting intelligent life in the Milky Way.
The impetus for this research, with its galaxy-spanning implications, began with a mystery right here at home – why did life take so long to move beyond simple organisms?
“Life has been around on Earth for about 4 billion years, but complex organisms like animals didn’t appear until about 600 million years ago, which is not long after the modern episode of plate tectonics began,” said Robert Stern of the University of Texas at Dallas. “Plate tectonics really jump-starts the evolution machine, and we think we understand why.”
Stern and his collaborator, Taras Gerya of the Swiss Federal Institute of Technology, propose that plate tectonics – the grinding movement of the upper layers of the planet at long geologic time scales – helped speed up the transition to complex life.
Early in Earth’s history, simple organisms formed in the ocean, but humanity – an advanced civilization capable of communicating across outer space – couldn’t exist if ancient life hadn’t transitioned to land. Vast, resource-rich continents were therefore a vital prerequisite for what Stern and Gerya call Active Communicative Civilizations (ACCs) like humanity to develop. But that alone wasn’t enough: the continents needed to move.
The geologic record on Earth suggests that plate tectonics accelerated evolution on land through five distinct processes: it increased the supply of nutrients; sped up the oxygenation of both the atmosphere and the ocean; tempered the climate; caused a high turnover rate of habitat formation and destruction; and offered non-catastrophic environmental pressure that forced organisms to adapt.
The end result of all these environmental pressures: us.
If Stern and Gerya are right, plate tectonics were a requirement for eventual innovations like the wheel, the smartphone, and the Apollo program.
And for other civilizations in the galaxy to develop similar technological marvels, perhaps their planets need plate tectonics too. But as far as we know, they’re rare.
Earth is the only planet in our solar system to feature plate tectonics. Volcanism exists on some other worlds, like Venus, Mars, and Io, but these worlds have a singular solid shell, rather than multiple moving plates. Similarly, ocean worlds like Enceladus and Europa are bound within an icy coating, forbidding any hypothetical life there from transitioning to land.
We don’t know for sure whether distant solar systems feature planets with plate tectonics – current space telescopes don’t have the resolution to make such determinations. But knowing that they might not enables a more accurate version of the Drake equation.
There are two essential factors proposed in the revised equation: the fraction of habitable exoplanets with large continents and oceans, and the fraction of those that have plate tectonics lasting more than 500 million years.
This version is much more nuanced than the original Drake equation, which simply took into account the fraction of habitable planets on which intelligent life had developed.
The Drake Equation, a mathematical formula for the probability of finding life or advanced civilizations in the universe. Credit: University of Rochester
“In the original formulation, this factor was thought to be nearly 1, or 100% — that is, evolution on all planets with life would march forward and, with enough time, turn into an intelligent civilization,” Stern said. “Our perspective is: That’s not true.”
Indeed. Their math reduces the percentage of these planets that develop ACCs to just 0.003% at minimum and 0.2% at maximum – a far cry from the original 100%.
When put together with all the other factors of the Drake Equation: number of stars formed annually, number of those stars with planets, number those planets that are habitable, number of those habitable planets with life, number of civilizations on those planets sending out detectable signals, and how long they send out the signals – well, the chances of finding intelligent alien life shrink considerably.
The implications of the original Drake equation were that ACCs should be common, and we should see them everywhere. But including plate tectonics in the equation changes the result, and makes it clear that it’s perfectly understandable why we don’t see ET all across the galaxy.
So intelligent alien life might be rarer than anyone thought. And Earth may be more special than we knew. All thanks to our planet’s fragmented, unruly, and shifting upper crust.
The three-body problem is one of Nature’s thorniest problems. The gravitational interactions and resulting movements of three bodies are notoriously difficult to predict because of instability. A planet orbiting two stars is an example of the three-body problem, but it’s sometimes called a “restricted three-body problem.” In that case, there are some potential stable orbits for a planet.
A new study shows that the nearby Alpha Centauri AB pair could host a Super Jupiter in a stable orbit.
“The three-body problem, which seeks stable orbit configurations among gravitating bodies, is a longstanding challenge in celestial mechanics,” Feng writes. Feng examines ? Centauri AB, our nearest binary neighbour, to understand if the system could host a super Jupiter and what orbit the giant planet could follow.
Feng isn’t the first astronomer to tackle the problem. “As the closest triple stellar system to Earth, Alpha Centauri system has attracted diverse studies in astronomy, including exoplanet stability,” Feng writes. Though the entire Alpha Centauri system is a triple star system, ? Centauri AB are far enough from the third star that they comprise a binary system.
Size comparisons for the Alpha Centauri A and B, Proxima Centauri, and the Sun. Image Credit: Planetary Habitability Lab/UPR Arecibo
There are some solutions to the three-body problem if one of the bodies has a negligible mass compared to the other two. ? Centauri AB is a pair of Sun-like stars. ? Centauri A is a class G star a little more massive than the Sun, and ? Centauri B is a class K star a little less massive than the Sun.
The study compares the ? Centauri AB system with a similar star system named GJ65AB (Gliese 65). It’s a binary pair known to host a Neptune-mass exoplanet. Though Gliese 65 is a pair of M-dwarfs, the comparison is still valuable because it “shares similar mass ratios and orbital eccentricities,” Feng writes. Gliese 65 is also close at only about 8.8 light-years from Earth. Feng also performed simulations of the ? Centauri AB system to test the idea of it hosting an exoplanet.
“The similarities between GJ65AB and Alpha Centauri AB, together with the newly detected stable super Neptune in the GJ65 system, suggest the stability of the corresponding potential super Jupiter in Alpha Centauri AB,” Feng writes. The Gliese 65 and the Alpha Centauri AB systems have nearly identical mass ratios and eccentricities. If GJ65 can host a planet in a stable orbit, can ? Centauri AB also host one?
Feng used the Mean Exponential Growth factor of Nearby Orbits (MEGNO) method to test the potential stability of a super Jupiter at ? Centauri AB. First, he used it to simulate the GJ65AB system and the newly discovered planet to verify the planet’s orbital stability. Then, he did the same with ? Centauri AB. “For this simulation, we restricted the semimajor axis of the planet to range from 0.1 to 5.0 au, and eccentricities less than 0.5,” Feng writes.
The MEGNO simulations for Gliese 65 showed that the newly discovered Neptune mass planet should be stable.
This figure from the research shows MEGNO results for Gliese 65. Dynamically stable regions of e (orbital eccentricity) and a (astronomical units) are shown in green, and the results show that the planet discovered around GJ65 should be stable. We identified the stable zone spanning from 0.1 to ~ 0.35
au, which contains all the stable orbits for ? ranging from 0 to 0.5 to ~0.35 au, which contains all the stable orbits for ? ranging from 0 to 0.5,” Feng explains. Image Credit: Feng 2024.
The next step was to find stable orbits for a planet orbiting ? Centauri AB. To do that, Feng used ? Centauri A as the primary star and injected a 350 Earth-mass planet at a distance of 23.336 AU. All of the other parameters were similar to GJ65 but scaled to ? Centauri AB. “We figured out the stable zone with ?
spanning from 0.1 to ~ 2.2 au, and ? ranges from 0 to 0.5,” Feng writes.
Feng says that the “potentially stable planet” should have ? about equal to 1.189 and ? about equal to 0.33. Those numbers place the planet in the stable zone in MEGNO results.
This figure from the study is a stability map based on MEGNO values for a Jupiter-mass planet in Alpha Centauri AB. Dynamically stable regions are coloured in green. For a stable planet around ? Centauri AB to “mimic” the stability of the newly discovered Neptune planet around GJ65, the planet would have ? about equal to 1.189 and ? about equal to 0.33, which places it right in the green stability zone. Image Credit: Feng 2024.
Of course, none of this means there is a planet there. It just shows that a potential stable orbit is available.
Feng’s work proposes that exoplanets in binary systems with nearly identical mass ratios and eccentricities can exhibit similar stability properties. “From this hypothesis, together with the newly detected Neptune-mass planet in the GJ65 system, which is similar to Alpha Centauri AB, we assume the existence of a potential Jupiter-mass planet with corresponding orbital parameters in Alpha Centauri AB should also be possible,” Feng writes.
No planets have been detected around ? Centauri AB, but that doesn’t mean there isn’t one there. Our planet-hunting methods are far from absolute, and there are bound to be many planets in nearby systems that we haven’t been able to detect yet.
There are many proposals for missions to the region or for telescopes designed to probe the system more deeply. Their neighbour, Proxima Centauri, has two confirmed exoplanets. And there’ve been tantalizing hints that Alpha Centauri A hosts a planet, but it remains only a candidate.
A true detection or emphatic non-detection may be years or decades away. Who knows? But at least Feng’s work shows that there could be a stable orbital home for a super Jupiter in the system.
Humans finally achieved controlled flight on another planet for the first time just a few years ago. Ingenuity, the helicopter NASA sent to Mars, performed that difficult task admirably. It is now taking a well-deserved rest until some intrepid human explorer someday comes by to pick it up and hopefully put it in a museum somewhere. But what if, instead of a quadcopter, NASA used a series of flexible-wing robots akin to bees to explore the Martian terrain? That was the idea behind the Marsbee proposal by Chang-Kwon Kang and his colleagues at the University of Alabama at Huntsville. The project was supported by a NASA Institute for Advanced Concepts (NIAC) grant back in 2018 – let’s see what they did with it.
The concept was initially inspired by work at the University of Tokyo on a dragonfly-like micro aerial vehicle (MAV). It is one of the few drones able to fly in Earth’s gravity using flexible wings that flap. But would it be useful on Mars?
Mars has both advantages and disadvantages compared to Earth when considering whether flexible wing flight is possible. In the advantage column, it has about ? of the gravity of our home planet, so less force is necessary for an aircraft to lift off. However, there is only about 1% of the atmosphere on Mars compared to Earth, so a flexible-wing aircraft would have significantly less atmosphere to push off to create that force.
Fraser explains Ingenuity’s final fate.
Ultimately, part of the Phase I project for the Marsbee grant was to determine whether the approach was feasible. But why do so in the first place? Ingenuity, known at the time as the Mars 2020 Helicopter, was already on the path to conducting the first powered flight on another planet. While it was successful at its stated mission, it had several downsides, including a relatively large size, which is at a premium on interplanetary trips, and a flight time limited to only about 3 minutes.
Neither of those limitations was a show-stopper, obviously, but a flexible-wing aircraft that is smaller and lighter could solve both of those problems. Engineers could potentially even store multiple craft in the same space as what Ingenuity needed in its ride-along with Perseverance. But would they work?
The short answer appears to be “not without additional technical development.” Modeling of the design showed weaknesses in a few areas that must be addressed before launching any successful Marsbee mission. The biggest hurdle appeared to be how flexible structures, like those that would make up the system’s wings, interacted with the uncertain aerodynamic environment of the Red Planet.
Video describing the Marsbee concept.
Credit – NASA 360 YouTube Channel
Other challenges include the weight of the battery pack and the development of a guidance and control system that could deal with the randomly windy Martian atmosphere while remaining small and light enough to fit on a flexible wing flyer. Also, it would be challenging to direct the flyers without a GPS, which doesn’t yet exist on Mars.
For now, efforts to develop Marsbees seem to have been put on hold, at least for the last several years. With the success of Ingenuity, many questions about the feasibility of flight on the Red Planet have already been answered. But with a little more technical development and derisking, it might be possible that someday we’ll see flights of robotic bees buzzing around the Red Planet.
In the latest chapter of “The Mystery of the Lunar Swirls,” planetary scientists have a new theory to explain these odd markings on the Moon’s surface. It invokes underground magmas and strange magnetic anomalies.
Lunar swirls are sinuous features that appear much lighter than the surrounding landscape. They extend for hundreds of kilometers and nobody’s quite sure why they exist. No astronaut has visited one of these weird regions, but that hasn’t stopped scientists from speculating based on images and magnetic field measurements. “Impacts could cause these types of magnetic anomalies,” said Michael J. Krawczynski, an associate professor of earth, environmental, and planetary sciences in Arts & Sciences at Washington University in St. Louis. Krawczynski points out that meteorites supply iron-rich material to areas on the Moon’s surface. However, these swirls exist in regions that aren’t necessarily disturbed by meteorites. So, what else could explain the swirls?
“Another theory is that you have lavas underground, cooling slowly in a magnetic field and creating the magnetic anomaly,” said Krawczynski, who, along with post-doctoral student Yuanyuan Liang, designed experiments to test this explanation. They measured the effects of different atmospheric chemistries and magmatic cooling rates on a mineral called ilmenite and found that under certain conditions, cooling subsurface lavas could be causing the ghostly lunar swirls.
Using Earth-based Geological Principles to Understand Lunar Swirls
Despite the fact that more than a dozen people have walked on the Moon, nobody visited a lunar swirl or picked up samples of their dust. That left Earth-bound planetary scientists to use Earth analogs for Moon rocks to understand lunar magnetism. “Earth rocks are very easily magnetized because they often have tiny bits of magnetite in them, which is a magnetic mineral,” Krawczynski said. “A lot of the terrestrial studies that have focused on things with magnetite are not applicable to the Moon, where you don’t have this hyper-magnetic mineral.”
So, the research team turned to ilmenite as their test material. It’s a titanium-oxide mineral with a weak magnetic signal. Ilmenite exists all over the Moon. It readily reacts to form magnetizable iron metal particles. “The smaller grains that we were working with seemed to create stronger magnetic fields because the surface area to volume ratio is larger for the smaller grains compared to the larger grains,” Liang said. “With more exposed surface area, it is easier for the smaller grains to undergo the reduction reaction.”
A sample of ilmenite found in Norway. This is the mineral tested to simulate subsurface magma on the Moon. CC-BY-SA 3.0 Rob Lavinsky, iRocks.com
Interestingly, planetary scientists have seen a similar reaction creating iron metal in lunar meteorites in samples from the Apollo missions. The difference, however, is that those samples came from surface lava flows. Krawczynski and Liang’s study focused on the types of magma that cooled underground.
“Our analog experiments showed that at lunar conditions, we could create the magnetizable material that we needed. So, it’s plausible that these swirls are caused by subsurface magma,” said Krawczynski. “If you’re going to make magnetic anomalies by the methods we studied, then the underground magma needs to have high titanium.”
Why Study Swirls on the Moon?
Those mysterious dust patterns aren’t just there by accident. They contain clues to the processes that shaped the lunar surface. In addition, if magnetism is involved in their formation, that says something about magnetism on the Moon as a whole.
Until astronauts can get to the Moon to study these swirls for themselves, the ilmenite experiment offers a good way to test the underground magma idea from afar, according to Krawczynski. Of course, it would be nice to get actual samples of underground rocks on the Moon, but that’s going to have to wait. “If we could just drill down, we could see if this reaction was happening,” he said. “That would be great, but it’s not possible yet. Right now, we’re stuck with the surface.”
Artist’s impression of the Lunar Vertex rover on the surface of the Moon. The rover is about 14 inches (35 centimeters) tall; the cylinder on top is the mast for the APL-built magnetometer. Credit: Johns Hopkins APL/Lunar Outpost/Ben Smith
Studies like Krawczynski and Liang’s will be quite useful when NASA sends future lunar missions to the surface. There’s a whole rover project, part of a mission called Lunar Vertex, planned to study Reiner Gamma. That’s one of the Moon’s better-known swirls. Vertex should launch this year and is a predecessor to the larger return to the Moon NASA plans for later this decade. That mission could confirm whether or not swirls are magnetic field-related. If not, then there’s something else going on at Reiner Gamma and other swirl sites.
Robotic companions are a mainstay of sci-fi series everywhere. From R2D2 to Johnny 5, these characters typically have a supporting role in the story and are helpful to their human companions. But what if they were integral to the humans in the story? So much so that they couldn’t live without their robotic compatriots? That’s the idea behind Biobot, which was given a NIAC grant in 2018 – why not use a robotic companion to carry supporting equipment on human extravehicular activities (EVAs) on other planets?
If you watch the footage from the Apollo missions, you can see how awkward it is for the astronauts to bend over to pick things up. Also, these extraordinarily naturally fit and gifted people seem to fall over an awful lot, given how coordinated they are on Earth. That’s probably because a 61 kg pack on their back is helping to keep them alive.
Each moonwalker had to carry a life support system on their suit to maintain conditions inside the suit that allowed them to breathe and not cook to death. This portable life support system (PLSS) weighed almost as much as the astronauts. It dramatically changed their center of gravity from its typical interalized location to somewhere behind their shoulder blades. That limited the astronaut’s mobility and, even with the light lunar gravity, limited the time they could participate in an EVA before becoming exhausted.
Alternatively, in microgravity, EVAs have taken place using umbilical cords and a larger life support system inside the space station or shuttle. This has proven successful, but managing the umbilical cords requires a significant amount of overhead—typically, another astronaut manages it for the person doing the EVA. Given the importance of productively utilizing all of an astronaut’s time, it would be better not to require that helping hand.
Dr. David Akin of the University of Maryland’s Department of Aerospace Engineering considered all that, and his solution is Biobot. The final design is a small rover capable of following an astronaut around on an EVA and attaching to their suit via an umbilical cord that the rover manages. As part of the NIAC grant Dr. Akin received, he and his team looked at potential design trade-offs as well a developed a working prototype of the system.
First, let’s discuss some advantages. Biobot removes the heavy weight from the astronaut’s back, freeing them from carrying it around and moving their center of gravity back to a more familiar place. It can also allow PLSS designers to add components that would otherwise be considered unsuitable for fitting into a backpack itself, such as radiative cooling systems.
Some UMD students testing an early prototype.
Credit – Akin et al.
It can also serve as a platform for holding collected samples or tools necessary for the mission. It can even let the astronaut ride on it in a pinch as a last resort in emergencies. Since it is mobile, the umbilical cord that would typically tie the astronaut to a base station is no longer an issue, and since it is designed to traverse any terrain an astronaut can, it should be capable of keeping up with them.
From some of the pictures in the NIAC final report, it appears the engineers working on the project had fun developing the system. They successfully showed a proof-of-concept of the basic functionality of what they expected the Biobot to do. They also plan to continue developing it, including a test phase at NASA’s “Rockyard” planetary surface simulator.
However, no additional NASA funding has been forthcoming. Though the paper mentions volunteer student support, it seems the Biobot idea is on hold for now. But someday, astronauts exploring the lunar or Martian surface might have a robotic companion with them that can provide both comic relief and life-giving support.
