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Utilizing regolith on the Moon or Mars, especially to refill propellant for rockets to get back off the surface, is a common theme in the more engineering-minded space exploration community. There have been plenty of proof-of-concept technologies that could move us toward that goal. One of the best supported was the Regolith Advanced Surface Systems Operations Robot (RASSOR). Let’s take a look at what made this project unique. It was initially conceived at Swamp Works, NASA’s version of Skunk Works, the famous Lockheed Martin development facility that worked on the SR-71 Blackbird and F-117 stealth plane. So far, it has gone through two iterations, known as 1.0 and 2.0, released in 2013 and 2016, respectively.  RASSOR consists of a chassis, a drive train, and two large bucket drum excavators. The excavating elements are on opposing sides of the rover, allowing the system to cancel out any horizontal forces caused by the excavating activity. On Earth, those horizontal forces would be offset by the physical weight of the digging machinery. Since weight is a precious commodity on space missions, this force-canceling technology is arguably the most crucial innovation in the system. Video showing testing of the RASSOR 2.0 prototype.Credit – NASA Video Collection YouTube Channel The RASSOR 2.0 prototype had several design goals, but it’s probably most helpful to walk through a use-case scenario. According to the soil samples collected by Curiosity and other rovers, around 2% of the regolith on Mars is water, even in the relatively “dry” regions outside the poles. Collecting that water could help refuel rockets and supply settlements with drinking water, radiation shielding, or water for agriculture. NASA commonly uses a mission structure involving four astronauts on a journey to Mars. In a paper describing the 2.0 version of the robot back in 2016, the authors, including Robert Mueller, the founder of the Swamp Works facility and a doyen of ISRU research, describe a mission structure that would see RASSOR mining 1,000,000 kg of Martian regolith per year and supplying 10,000 kilograms of oxygen to the mission. To do so, it would utilize a lander with processing capabilities for separating the useful parts from the chaff and would trek from the lander site to the regolith collection site about 35 times a day. With a charging cycle that would take about 8 hours a day, that would leave upwards of 16 hours to continuously mine the surface of Mars for these valuable materials. Fraser describes how to live off the land in space using ISRU. The paper goes on to describe the design process for the RASSOR’s various subsystems, including the powerful actuators that make up the majority of the weight of the system. They also used 3D-printed titanium to make the bucket drum excavating tools, which required some ingenious machining by Swamp Work’s machinists.  But in the end, they did make a working prototype. They tested it with improvements like a 50% drop in weight and an autonomous mode that utilizes simple stereo-vision cameras. The team believes this project is ready to move on to the next phase, taking a step closer to making it a reality. That paper, however, was published eight years ago. A relatively detailed internet search doesn’t produce any results for RASSOR 3.0 other than a brief mention at the end of the 2.0 paper. So, for now, it seems the project is on hold. However, another NASA project, the Lunabotics Challenge, keeps university teams working toward effectively mining regolith for us in ISRU systems. Maybe one of those teams will pick up where the RASSOR team left off – or come up with a completely new design. We’ll have to wait and see. Learn More:Mueller et al. – Design of an Excavation Robot: Regolith Advanced Surface Systems Operations Robot (RASSOR) 2.0UT – Japan Tests Robotic Earth-Moving Equipment in a Simulated Lunar JobsiteUT – NASA Wants to Learn to Live Off the Land on the MoonUT – What is ISRU, and How Will it Help Human Space Exploration? Lead Image:CAD model of the RASSOR 2.0 excavating robot.Credit – Mueller et al. The post A Single Robot Could Provide a Mission To Mars With Enough Water and Oxygen appeared first on Universe Today.

One of the easiest ways to find exoplanets is using the transit method. It relies upon monitoring the brightness of a star which will then dim as a planet passes in front of it. It is of course possible that other objects could pass between us and a star; perhaps binary planets, tidally distorted planets, exocomets and, ready for it…. alien megastructures! A transit simulator has been created by a team of researchers and it can predict the brightness change from different transiting objects, even Dyson Swarms in construction.  51 Pegasi-b was the first exoplanet discovered in 1995 and it sparked the development of numerous ground-based and space-based instruments. The launch of the Kepler Space Telescope and the Transiting Exoplanet Survey Satellite (TESS) in 2018 popularised the transit method, leading to the discovery of over 4,000 exoplanets. As instruments have become increasingly sensitive and precise, research has progressed from simply detecting exoplanets to studying their detailed characteristics. Illustration of NASA’s Transiting Exoplanet Survey Satellite. Credit: NASA’s Goddard Space Flight Center Transit photometry has uncovered signatures of many interesting phenomena beyond the detection of exoplanets and eclipsing binaries. This technique has been instrumental in identifying features such as star-spots, and signatures of tidal interactions between host stars and exoplanets leading to significant growth in the sub-field of Asteroseismology The study of transiting exoplanets and their timing variations has led to many discoveries. Non-transiting planets in distant solar systems have been found, orbital decay, disintegrating planets, exocomets and exomoon candidates has all been identified. Additionally, and perhaps of particular interest is that transit photometry has detected signals that have sparked interest in the search for technosignatures for the evidence of advanced civilizations. It is important to note that no technosignatures have been confirmed yet but such signatures would not arise form natural processes and would demonstrate the presence of intelligent life. The signatures would come from a wide range of astroengineering projects like Dyson Spheres (a theoretical shell surrounding a star to capture its energy output) or the newly conceptualised Dyson Swarms (habitable satellites and energy collectors that orbit the star in formation.  The research team led by Ushasi Bhowmick from the Indian based Space Application Centre has reported that they have developed a transit simulator that can not only generate light curves for exoplanets but also for any object of any size or shape! The simulation uses the Monte-Carlo technique that predicts all possible outcomes of an uncertain event. In this instance it can predict the light curve when an object of any shape or size transits across the disk of star.  Artist’s impressions of two exoplanets in the TRAPPIST-1 system (TRAPPIST-1d and TRAPPIST-1f). Credit: NASA/JPL-Caltech When the simulation was tested against actual exoplanet systems such as Trappist-1 it nicely predicted the light curve. It can also be used to model tidal distortions in binary star systems and even predict the light curve of non-natural objects such as the alien megastructures. The simulator has shown itself to be an invaluable method for understanding a wide range of transit phenomena.  Source : A General-Purpose Transit Simulator for Arbitrary Shaped Objects Orbiting Stars The post That’s No Planet. Detecting Transiting Megastructures appeared first on Universe Today.

Universe Today has had some incredible discussions with a wide array of scientists regarding impact craters, planetary surfaces, exoplanets, astrobiology, solar physics, comets, planetary atmospheres, planetary geophysics, cosmochemistry, meteorites, radio astronomy, extremophiles, organic chemistry, black holes, cryovolcanism, and planetary protection, and how these intriguing fields contribute to our understanding regarding our place in the cosmos. Here, Universe Today discusses the mysterious field of dark matter with Dr. Shawn Westerdale, who is an assistant professor in the Department of Physics & Astronomy and head of the Dark Matter and Neutrino Lab at the University of California, Riverside, regarding the importance of studying dark matter, the benefits and challenges, how dark matter can teach us about finding life beyond Earth, the most exciting aspects about dark matter he’s studied throughout his career, and advice for upcoming students who wish to pursue studying dark matter. So, what is the importance of studying dark matter? “About 80% of the mass of all matter in the universe is dark matter, despite the fact that our (otherwise extremely successful) model of fundamental particle physics cannot explain what it is,” Dr. Westerdale tells Universe Today. “We can see the gravitational influence of dark matter in our own galaxy and throughout the entire structure of the observable universe. It leaves a clear imprint on all of our cosmological and astrophysical observations through these gravitational interactions, so we know it is there and it does a remarkable job of explaining what we see. But we have no idea what it actually is made of, and this is an essential part of understanding nature.” The term “dark matter” was first coined in 1906 by French mathematician and theoretical physicist, Dr. Henri Poincaré, to describe work from 1884 by the British mathematical physicist, Dr. William Thomson (Lord Kelvin), regarding velocities of stars and some potentially being dark bodies. Throughout the rest of the 20th century, dark matter became a focal point in hypothesizing the behavior of galaxies and galaxy clusters with countless studies being published from academia, including the California Institute of Technology, along with research organizations like the SETI Institute. Despite decades of research, including the hypothesis of “cold”, “warm”, and “hot” dark matter, this mysterious substance has yet to be observed. Therefore, what are some of the benefits and challenges of studying dark matter? Dr. Westerdale tells Universe Today, “We haven’t found it yet, but we have ruled out many models, and in doing so we have helped refine our understanding of nature by ruling out possible modifications to the Standard Model of particle physics. On a sociological level, the study of dark matter has led to many new technologies for detecting radiation. Some of these may lead to new quantum technologies, and others are being developed into new medical imaging devices, just to name a few examples.” The three methods for attempting to observe dark matter include direct detection, indirect detection, and laboratory experiments using a myriad of laboratories from several countries around the world, including the Large Hadron Collider, which is the world’s largest particle collider. Additionally, several ground- and space-based telescopes have conducted surveys to try and create dark matter maps, including NASA’s Hubble Space Telescope, the Canada-France-Hawaii Telescope, the VLT Survey Telescope, and the Subaru Telescope. But what are the most exciting aspects about dark matter that Dr. Westerdale has studied during his career? Dr. Westerdale tells Universe Today, “To me the most exciting aspect of dark matter research has been the magnitude of the question. We have such successful models of cosmology and particle physics, and yet for all the success of these models, we still don’t know what most of the universe is even made of or how it got here!” The study of dark matter comprises some of the most fundamental questions pertaining to cosmology, the nature of the universe, and our place in it. What is the universe made of? How did it form? How did galaxies form? How do galaxies behave the way they do? How has all of this led to us being here and writing articles about dark matter like this one? The answers to these questions continue to elude astrophysicists, cosmologists, and countless other scientists despite decades of research, experiments, models, and hypotheses. Dr. Westerdale tells Universe Today, “One of the fun challenges of dark matter detection is that we are looking for extremely rare interactions and so we have to go to extraordinary lengths to make our experiments as quiet as possible. We put our detectors in deep underground labs, up to a mile underground, to avoid noise from cosmic rays, and levels of radioactivity that are normally so low they cannot be measured can swamp the signals we’re looking for. It is an exciting challenge to confront these things in our research and figure out how to design detectors that can meet all of our goals.” Despite the lack of observing dark matter and confirming its existence, this nonetheless signals that the next generation of dark matter enthusiasts, whether they become astrophysicists, cosmologists, or come from other scientific backgrounds, will have their work cut out for them, with some possibly being the ones to confirm dark matter’s existence. Like nearly all scientific research trajectories, the study of dark matter involves constant collaboration between scientists from a myriad of backgrounds and expertise’s. Therefore, what advice can Dr. Westerdale offer to upcoming students who wish to pursue studying dark matter? Dr. Westerdale tells Universe Today, “Experimental dark matter physics requires a very large breadth of knowledge, and so don’t silo your studies — any physics, math, and engineering skills you learn will at some point be useful. Programming skills are especially important, as are learning statistics, chemistry, and other engineering skills. And when you encounter something new, take the time to learn how it works on a fundamental level — it will be worth it later on once you can see how it fits into the big picture.” Will we ever observe dark matter and how will it help us better understand our place in the universe in the coming years and decades? Only time will tell, and this is why we science! As always, keep doing science & keep looking up! The post Dark Matter: Why study it? What makes it so fascinating? appeared first on Universe Today.

One of the most fundamental questions astronomers ask about an object is “What’s its distance?” For very faraway objects, they use classical Cepheid variable stars as “distance rulers”. Astronomers call these pulsating stars “standard candles”. Now there’s a whole team of them precisely clocking their speeds along our line of sight. What makes a classical Cepheid a “standard candle” in the darkness of the Universe? It’s that pulsation. Not only does a Cepheid grow larger in a regular rhythm, but its brightness changes over predictable periods of time. In the early 1900s, astronomer Henrietta Leavitt studied thousands of these stars. She found something pretty interesting: there’s a strong relationship between a Cepheid’s luminosity and its pulsation period. And that’s a useful relationship. When you compare a Cepheid’s luminosity to its pulsation period, you can derive the star’s distance. This relationship appears to be true for all known Cepheids. That’s why they’re considered an important part of the cosmic distance ladder. They’re the main benchmark for scaling the huge distances between galaxies and galaxy clusters. Types of Cepheids There are different “flavors” of Cepheids. The “classical” ones have pulsation periods ranging from a few days to a few months. They’re all more massive than the Sun and can be up to a hundred thousand times more luminous. Their radii can change pretty drastically during a cycle—some grow by millions of kilometers and then shrink. Type II Cepheids have pulsation periods between 1 and 50 days and are usually very old, low-mass stars. There are other types, including anomalous Cepheids with very short periods. Scientists also know about double-mode Cepheids with “heartbeats” that pulsate in two or more modes. Some pretty well-known stars are Cepheid variables. For example, Polaris—the well-known “North Star” is one, as is RR Puppis, Delta Cephei, and Eta Aquilae—all visible from Earth. Why these stars pulsate is still being studied but here’s a very basic look at their process. The core of the star produces heat which heats the outer layers. They expand, and then cool. Radiation is escaping, which makes the star appear brighter. The cooler gas contracts under gravity and makes the star look smaller and cooler. Of course, the devil is in the details, which is why astronomers want to know more about the processes these stars undergo. Polaris A (Pole Star) with its two stellar companions, Polaris Ab and Polaris B. Polaris itself is a Cepheid type variable star. Artists impression. Credit: NASA However, it turns out Cepheids are not exactly easy to study. For one thing, it’s tough to measure their pulsations and radial velocities accurately. In addition, some have companion stars and the presence of a nearby star complicates any measurements. For another thing, different instruments and measuring methods give slightly different results, which doesn’t help astronomers understand those stars any better. Precision Measurements of Cepheid Variables Measuring the intricacies of Cepheid pulsations requires spectroscopic techniques that can measure light from stars and break it down into its component wavelengths. That reveals a lot of data about a star, including its chemical makeup, temperature, and motions in space. Calibrated Period-luminosity Relationship for Cepheid variables. Courtesy Spitzer Space Telescope/IPAC. A worldwide consortium of astronomers led by Richard I. Anderson at Switzerland’s École Polytechnique Fédérale de Lausanne (EPFL) is measuring specific properties of classical and other Cepheids using two high-resolution spectrographs. One is called HERMES on La Palma in the northern hemisphere and the other is CORALIE in Chile. They both detected tiny shifts in the light of target Cepheids. Those shifts gave valuable information about the motions of the stars. “Tracing Cepheid pulsations with high-definition velocimetry gives us insights into the structure of these stars and how they evolve,” he said. “In particular, measurements of the speed at which the stars expand and contract along the line of sight—so-called radial velocities—provide a crucial counterpart to precise brightness measurements from space. However, there has been an urgent need for high-quality radial velocities because they are expensive to collect and because few instruments are capable of collecting them.” VELOCE is on the Job The team’s measurement project is called the VELOCE Project—short for VELOcities of CEpheids. It’s 12-year-long collaboration among astronomers and astrophysicists. Anderson began the VELOCE project during his Ph.D work at the University of Geneva, continued it as a postdoc in the US and Germany, and has now completed it at EPFL. According to Ph.D student Giordano Viviani, the data from the project are already enabling new discoveries about Cepheids. “The wonderful precision and long-term stability of the measurements have enabled interesting new insights into how Cepheids pulsate,” Viviani said. “The pulsations lead to changes in the line-of-sight velocity of up to 70 km/s, or about 250,000 km/h. We have measured these variations with a typical precision of 130 km/h (37 m/s), and in some cases as good as 7 km/h (2 m/s), which is roughly the speed of a fast walking human.” Uncovering New Details about these Pulsating Stars The VELOCE project’s precision measurements also revealed some strange facts about these stars. For example, there’s an interesting phenomenon called the Hertzsprung Progression. It describes double-peaked bumps in a Cepheid’s pulsations. Astronomers aren’t quite sure yet why these bumps occur. But, they could give some insight into the structure of Cepheid variables, particularly the so-called “classical” ones. Other Cepheids show very complex variability, and changes in their radial velocities are not always consistent with predicted periods, according to postdoctoral researcher Henryka Netzel. “This suggests that there are more intricate processes occurring within these stars, such as interactions between different layers of the star, or additional (non-radial) pulsation signals that may present an opportunity to determine the structure of Cepheid stars by asteroseismology,” Netzel said. As part of their study, the team also measured 77 Cepheids that are part of binary systems. One in three Cepheids “lives” in a binary system, and often those unseen companions are detectable by velocity measurements. Characterizing the different “flavors” of Cepheids and the intricacies of their pulsations has larger implications than determining their radial velocities and bumps in their periods, according to Anderson. “Understanding the nature and physics of Cepheids is important because they tell us about how stars evolve in general, and because we rely on them for determining distances and the expansion rate of the Universe,” Anderson said, noting that VELOCE is also providing a valuable “cross-check” with Gaia measurements. It’s on track to conduct a large-scale survey of Cepheid radial velocity measurements. Cross-checking with Gaia Additionally, VELOCE provides the best available cross-checks for similar, but less precise, measurements from the ESA mission Gaia. That spacecraft is on track to conduct the largest survey of Cepheid radial velocity measurements. Data from that mission provides a growing three-dimensional map of millions of stars in the Milky Way and beyond. It not only charts their positions but also their motions (including radial velocity), as well as temperatures and compositions. Combined with high-precision data from VELOCE about Cepheids, astronomers should soon be able to get a handle on stellar and galactic evolutionary history. For More Information High-precision Measurements Challenge the Understanding of CepheidsVELOcities of CEpheids (VELOCE) The post Cepheid Variables are the Bedrock of the Cosmic Distance Ladder. Astronomers are Trying to Understand them Better appeared first on Universe Today.

One proposal offers a unique method to directly image ExoEarths, or rocky worlds around nearby stars. It’s the holy grail of modern exoplanet astronomy. As of writing this, the count of known worlds beyond the solar system stands at 6,520. Most of these are ‘hot Jupiters,’ large worlds in tight orbits around their host star. But what we’d really like to get a look at are ‘ExoEarths,’ rocky worlds (hopefully) like our own. Now, a recent study out of the University of Paris, the European Southern Observatory (ESO) and the University of Cambridge entitled Exoplanets in Reflected Starlight with Dual-Field Interferometry: A Case For Shorter Wavelengths and a Fifth Unit Telescope at VLTI/Paranal suggests a method to do just that in the coming decade. This would involve one the most massive telescope complexes ever built: the Very Large Telescope. Based at Paranal Observatory in Chile, this array consists of four 8.2-metre telescopes working in concert via a method known as interferometry. The study advocates adding a fifth telescope, giving the VLT the capacity to see Jupiter-sized worlds shining directly in the host star’s light… and with a few key upgrades, the new and improved VLT could perhaps image ‘ExoEarths’ directly. Pioneering Dual-Field Interferometry Interferometry is the method of using superimposed waves collected from two telescopes to merge a signal into one image. This method allows for a resolution equivalent to the baseline between the two collecting instruments, bypassing the need for one enormous telescope. Long baseline radio interferometry can span continents, and there are plans to move the technique into space. Interferometry at visual wavelengths is a tougher proposition, one that’s just reaching its true potential. Dual Field Interferometry uses the technique to simultaneously focus on two narrow fields in context within a larger field. One field is centered on the host star, and one on the target exoplanet. This can then minimize (subtract) photon shot noise from the primary, allowing for a clear view of the target world. “With this technique, at the VLTI, we have a resolution equivalent to having a telescope of 130 meters,” lead author on the study Sylvestre Lacour (University of Paris) told Universe Today. “This allows us to distinguish the exoplanet’s light from the contamination by the stellar light, allowing to detect exoplanets very close to the star.” ESO’s Very Large Telescope (VLT) timelapse of Beta Pictoris b around its parent star. This young massive exoplanet was initially discovered in 2008 using the NACO instrument at the VLT.  The sequence tracked the exoplanet from late 2014 until late 2016, using the Spectro-Polarimetric High-contrast Exoplanet REsearch instrument (SPHERE) — another instrument on the VLT. “The term ‘dual’ in dual interferometry comes from the fact the we are observing at the same time the exoplanet and the star with the optical interferometer,” says Lacour. “This is necessary to be able to probe at the same time the phase of the stellar light and the phase of the exoplanet light, to be able to distinguish the two. By ‘phase’ I mean the phase of the electric field entering the interferometer.” The GRAVITY instrument at the VLTI in Paranal. Credit: ESO The Hunt for ExoEarths The method is already being applied to reveal nearby worlds. “We typically observe exoplanets at a few tens of parsecs,” says Lacour. “They are massive exoplanets, more massive than Jupiter (between 4 and 10 Jupiter masses), and they are young, less than 50 million years (old). You can look for the results for the GRAVITY collaboration, operating the GRAVITY instrument at Paranal.” One key technique used to overcome the effects of ‘shot noise’ is what’s termed as ‘apodization’. “Apodization is a way to decrease the contamination of the stellar light entering into our interferometer,” says Lacour. “It is similar to adding a coronagraph.” Apodization makes ground-based systems such as the VLTI viable in terms of exoplanet science and direct detection. Other efforts such as the European Space Agency’s Proba-3 space telescope launching later in 2024 will use a free flying coronagraph to directly image exoplanets. A pro to this method is it can characterize orbits within a few Astronomical Units from their host star. Other techniques observe planets very close in, or very far out. The downside of the method is that it’s a very difficult technique, right on the grim edge of what’s currently possible with existing telescopes. An artist’s conception of the E-ELT telescope. Credit: Swinburne Astronomy Productions/ESO The Future of Exoplanet Astronomy There’s already a good case for plans to extend the VLTI baseline to a fifth instrument. This includes direct imaging for worlds known orbiting around nearby stars to include Proxima Centauri B and Tau Ceti e. Lessons learned from the VLTI could also work for the Extremely Large Telescope, which may see first light in 2028. An artist’s conception of Tau Ceti e, a possible ‘ExoEarth’ in the habitable zone. Ph03nix1986/Wikimedia Commons/CCA 4.0 It’ll be exciting to see more nearby worlds revealed by this technique in the coming decade. The post Existing Telescopes Could Directly Observe ‘ExoEarths…’ with a Few Tweaks appeared first on Universe Today.