Rovers on alien worlds need to be built of strong stuff. The dry rugged terrain can be punishing on the wheels as they explore the surface. In order to prevent the damage to the wheels, NASA is testing a shape memory alloy material that can return to its original shape after being bent, stretched, heated or cooled. NASA has already used this material for years but never in tires, in what may be its perfect application.
Rovers are a common sight now as they explore the surface of other planets. Their versatility and ability to respond to the environment and commands from mission controllers make them a valuable exploration tool. Cameras, sensors, collection instruments and analysis tools are common onboard systems that provide information about the local environment. There have been a number of well known examples such as the Mars rovers; Spirit, Opportunity, Curiosity and Perseverance. They have helped us to learn about the geology, atmosphere, presence of water and habitability of the planet. Taken Mars as a case in point, we have only explored 1% so there is most certainly still a need for robotic rover exploration.
Mars Perseverence rover sent back this image of its parking spot during Mars Solar Conjunction. Courtesy NASA/JPL-CaltechPerhaps the most robust aspect of a rover is its wheels and tires. They must be capable of coping with rugged, uneven and rocky surfaces yet light enough not to cost a fortune to launch to the alien worlds. NASA has recently undertaken and completed a rigorous round of testing of a new tire using revolutionary shape memory alloys material. The tire technology was developed at the Glenn Research Center in partnership with Goodyear Tire and Rubber.
The shape memory alloys have been used for numerous applications due to their unique feature of being able to return to their original shape after being deformed. They are typically made from combinations of metals like nickel and titanium which exhibit the property known as super-elasticity. The fascinating property allows the material to ‘remember’ its original shape and have been used in medical devices like stents, wires and various aerospace components. This is the first time NASA have explore their use in tyres.
Image of the Opportunity rover’s front wheel, taken on June 9th, 2004. Credit: NASA/JPL/CornellThe idea about their use in rover wheels came about rather by chance. Dr. Santo Padula II, materials research engineer at NASA Glenn Research Center came across Colin Creager a NASA mechanical engineer while leaving a meeting. Creager explained about the work he was doing in the Glenn Simulated Lunar Operations Laboratory (a simulated lunar surface) to improve rover performance. Having enjoyed a tour of the facilities, Padula noticed the rover tyres were made of steel. Padula immediately realised that the steel wheels would get irreversibly damaged through use ultimately leading to their failure to provide traction. On discussing the matter, Creager explained it was the only problem they couldn’t solve.
As a materials researcher Padula told him about his work on a new alloy that would solve the problems with wheel irreversible deformations. The SMA tires concept was born. The two joined forces to develop the first nickel-titanium tires that would deform but return to their original shape and, after rigorous testing, the SMA tires became the solution to Creager’s problem.
The team is now looking for other ways that SMAs can be used in other space exploration such as habitat protection. The extreme environment of space with meteoroid impacts being a regular occurrence make memory alloys the ideal solution. As robotic exploration continues apace and human exploration of our Solar System moves forward, SMAs look set to be a real game changer in ensuring safety and continued operation of a multitude of space hardware.
Source : NASA Sets Sights on Mars Terrain with Revolutionary Tire Tech
Link : https://www.nasa.gov/technology/nasa-sets-sights-on-mars-terrain-with-revolutionary-tire-tech/
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The study of exoplanets is challenging enough with the immense distances and glare from the host start but astronomers have taken planetary system explorations to the next level. A team of astronomers have recently announced that they have observed belts of icy pebbles in systems with exoplanets. Using a radio telescope they have been able to detect wavelengths of radiation emitted by millimeter-sized pebbles created by exocomet collisions! Based upon this survey, they have found that about 20% of planetary systems contain these exocometary belts.
Our own Solar System is peppered with them so it’s perfectly reasonable to expect to find them in planetary systems around other stars. The so called exocomets are generally only detected when they pass through or near to our own system. It would also be reasonable to assume they are made of the same icy and rocky material as our own comets but they can still provide valuable insights into the formation and evolution of exoplanetary systems. The first such comet was discovered around the star Beta Pictoris in the 19080s.
Comet 12P Pons-Brooks. Credit: Michael Jaeger.A team of astronomers that have been working upon the REASONS (REsolved ALMA and SMA Observations of Nearby Stars) study and have imaged exocomet belts around nearby stars! ALMA (the Atacama Large Millimeter/submillimeter Array) and SMA (Submillimeter Array) are powerful radio observatories that explore the skies in millimetre and submillimeter wavelengths. ALMA is based in northern Chile and composed of an array of 66 dishes and SMA is in Hawaii consisting of 8 dishes.
The Atacama Large Millimeter/submillimeter Array (ALMA). Credit: C. Padilla, NRAO/AUI/NSFThe team led by astrophysicists from Trinity College Dublin have been revealed images that reveals pebbles and hence the locations of exocomets. In most cases, they are located tens to hundreds of astronomical units from their host star (one astronomical unit is the average distance from Earth to the Sun.) At theses immense distances from the star the temperatures will be in the between -250 and -150 degrees where any water will be frozen. The observations have detected the radiation emitted from the exocometary collisions. It’s the first time such an in depth analysis has been completed and to date, they have released images from belts in 74 exoplanetary systems.
The rings are quite varied with some multiple disks and risks, others exhibiting high eccentricity. The eccentricity suggests that there are planets in these systems causing gravitational effects to modify the distribution of the pebbles in the belts.
Co-author of the study Dr Sebastian Marino, Royal Society University Research Fellow from the University of Exeter explained “The images reveal a remarkable diversity in the structure of belts. Some are narrow rings, as in the canonical picture of a ‘belt’ like our Solar System’s Edgeworth-Kuiper belt. But a larger number of them are wide, and probably better described as ‘disks’ rather than rings.”
The study was able to develop a model showing that the number of pebbles seems to decrease for older planetary systems. This makes sense since an aged system will have run out of exocomets to generate the debris. They also found that the decrease in pebbles is faster when the belt is closer to the star.
Over the last few decades the focus seems to have been on exoplanets but this recent study has shown that the field of exocometary research is well and truly off the starting blocks and revealing fascinating insights into the exoplanetary systems.
Source : Astrophysicists reveal structure of 74 exocomet belts orbiting nearby stars in landmark survey
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In 2017, Dr. Vinay Prasad said an anti-vaccine doctor was a "quack". What changed?
The post Dr. Vinay Prasad 2025 = Dr. Kelly Brogan 2015 first appeared on Science-Based Medicine.Red dwarfs always make me think of the classic British TV science comedy show in the 90’s that was named after them. The stars themselves better little resemblance to the show though. They are small, not surprisingly red stars that can generate flares and coronal mass ejections that rival many of the much larger stars. A team of astronomers have recently used the Chandra X-Ray Observatory to study Wolf 359 and found it unleashes brutal X-ray flares that would be extremely damaging to life on nearby planets.
Red dwarf stars are small, cool, and very long-lived stars that shine with only a fraction of the brightness of our Sun. They have a mass less than half of the Sun’s and their surface temperatures range from 2,500 to 4,000 degrees Celsius. Because they burn their fuel so slowly, red dwarfs can last for trillions of years, far outliving more massive stars. They are common across the cosmos making up about 70-80% of all stars in the Galaxy but despite this they are hard to spot with the naked eye.
An artistic impression of Trappist-1 B shortly before it passes behind the cool, red dwarf star, Trappist-1. Such stars are known for their activity with large starspots and eruptions. Trappist-1 B may experience intense volcanism. Credit Thomas Muller (HDA.MPIA)Wolf 359 is a one such red dwarf star located about 7.8 light-years away from Earth, making it one of the closest stars to our solar system. It’s still too dim to be seen without a telescope though shining at just one-thousandth the brightness of the Sun. It’s part of the constellation Leo and has a mass only about 12% of our Sun’s, with a surface temperature around 4,000 degrees Celsius. Wolf 359 is a relatively young star, but due to its low mass, it will burn its hydrogen fuel slowly and could remain stable for tens of billions of years.
With the intense radiation emissions from Wolf 359 its very likely that any planets in orbit around it will be unable to maintain a stable life supporting atmosphere. A team of astronomers however have been studying it with NASA’s Chandra X-Ray Observatory and ESA’s XMM Newton. They have found that only a planet that has green house gasses, just like Earth, in its atmosphere could sustain life. Given that red dwarfs are the most prevalent stars in the Universe, astronomers have explored them to find evidence of exoplanets but to date, with little success. The team found evidence for two planets in orbit about Wolf 359 but not all scientists are convinced.
Artist’s illustration of ChandraEvery star has a habitable zone and its location is determined by the temperature and energy output from the star itself. The outer limits for this zone around Wolf 359 is about 15% of the distance between Earth and Sun. The two yet to be confirmed exoplanets orbit the star outside the habitable zone; one is too close, the other to far.
As they studied the system over 3.5 days, they observed 18 X-Ray flares from Wolf 359. That was just over 3.5 days though and the team propose that more powerful and more damaging flares will occur from time to time. These intense X-ray flares are the chief reason that any planets in orbit must be within the habitable zone and will need an atmosphere rich in carbon dioxide to sustain habitable conditions. It’s unlikely however, that any planet within the habitable zone will be able to keep its atmosphere due to the strength of the wind blowing upon it.
Source : Exoplanets Need to Be Prepared for Extreme Space Weather, Chandra Find
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If you want to know what the newly forming Solar System looked like, study planetary disks around other stars. Like them, our star was a single star forming its retinue of worlds and other stars did the same. This all happened 4.5 billion years ago, so we have to look at similar systems around nearby stars.
Recently astronomers used radio and optical telescopes to study a collection of so-called “double planetary disks”. These are collections of material around binary stars, sometimes also called “protoplanetary disks.” They zeroed in on a system called DF Tau because it showed some peculiar characteristics. You’d think the planetary disks in those pairs would be roughly the same since they formed from the same raw materials as their parent stars. However, they show some surprising differences from each other.
DF Tau and Its Double Planetary DisksDF Tau lies just over 400 light-years away from us in the constellation Taurus. It’s in a giant molecular cloud that contains hundreds of newborn stars. DF Tau is two fairly young stars of equal mass. They’re in a 48-year-long orbital dance with each other, and very likely formed together in the same cloud of gas and dust. However, their disks show distinct differences. The brighter, primary star has an active inner disk. The secondary star’s inner region appears to have almost completely disappeared. What does this say about the formation and evolution of these regions and their planets (if they have any)?
According to Dr Taylor Kutra of Lowell Observatory and one of the researchers looking at this system, it’s complex. “The dispersal of circumstellar disks is a complicated process with many unknowns,” said Kutra. “By looking at systems that form together, we can control one major variable: time. DF Tau and other systems in our survey tell us that disk evolution isn’t strictly a function of time, other processes are at play.”
Disk MechanicsThink of planetary disks like giant wheels spinning in the hearts of molecular clouds. As it moves, material from the disk clumps together. That forms planetesimals, and ultimately planets. The process of planet formation eventually uses up the material in the disk. It doesn’t take long for the material to dissipate like this. There’s nothing left of our own Solar System’s circumstellar birthplace, so we have to look for other examples to understand our own.
Artist’s depiction of a protoplanetary disk in which planets are forming. Credit: ESO/L. CalçadaFinding such disks around other stars is a snapshot of a planetary crèche early in the formation and evolution process. Finding a pair of them as a binary is an extraordinary chance to understand the complications of planetary formation in such a pair. The fact that one of them has experienced dissipation of its inner region raises a lot of questions. What’s happening to cause that dissipation? Could it be due to planetary formation taking place more rapidly in one disk? Is there formation taking place in the brighter one? What other processes could cause such an imbalance in the two structures?
Kutra and a team of astronomers used the NRAO’s Atacama Large Millimeter Array in Chile, as well as optical and infrared observations from other facilities such as the Keck Observatory to study the pair. Their data should help shed light on the process of planetary formation in the paired disks, and explain the differences. One possibility to explain the differences in dissipation is to look at the viscosities of the individual disks. Another is to look for the presence of a substellar companion carving out gaps in the one surrounding the secondary star. It’s also possible that the newborn stars could affect their disks in different ways. In some systems, those stars work to evaporate their disks quite quickly.
Future Work NeededDF Tau wasn’t the only system they studied. There are many other sources in the ALMA survey. They allow astronomers to study how circumstellar disks evolve, particularly in binary systems. The DF Tau system merits more study since astronomers are just beginning to understand its characteristics.
Once astronomers get a handle on these processes, it should help us understand planet formation in circumstellar disks. That’s because their evolution directly affects the timing of planetary formation. Astronomers will continue to probe the density of the disks, and the timing of changes in the inner and outer regions—and if all goes well—search for newly forming worlds there and in other systems they find in the future. Since not all stars form as singletons (like the Sun did), checking out more binaries should give us a better understanding of binary star and planet evolution.
For More InformationDouble the Disks, Double the Discovery: New Insights into Planet Formation in DF Tau
Sites of Planet Formation in Binary Systems. II. Double the Disks in DF Tau
Star Formation in the Taurus-Auriga Dark Clouds
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A spacecraft takes between about seven and nine months to reach Mars. The time depends on the spacecraft and the distance between the two planets, which changes as they follow their orbits around the Sun. NASA’s Perseverance is the most recent spacecraft to make the journey, and it took about seven months.
If it didn’t take so long, then Mars would be within reach of a human mission sooner rather than later. NASA is exploring the idea of using nuclear electric propulsion to shorten the travel time.
Sending a crewed mission to Mars is much more complicated than sending a robotic explorer like Perseverance. Perseverance will be left there after its mission ends. But humans need to return to Earth. One of the main restrictions is launch windows. These occur every 26 months when the planets are closest to one another, making the trip shorter and more manageable. So, a crewed return mission to Mars could take about four years, depending on factors like the crew’s time on the planet.
A more efficient propulsion system under development could transport a crew to Mars on a round-trip in only about two years, according to its proponents. Engineers at NASA’s Langley Research Center are working on a nuclear electric propulsion system that could bring Mars within reach in these timeframes. These systems use a nuclear reactor to generate electricity, which is used to ionize or positively charge gaseous propellants and create thrust.
But there’s a catch: it has to be assembled in space.
The system is called the Modular Assembled Radiators for Nuclear Electric Propulsion Vehicles, or MARVL. MARVL is connected to NASA’s goal of developing a Mars Transit Vehicle, aka Deep Space Transport, in the next decade or by the late 2030s.
One of the system’s components is its heat dissipation system. The system is an array about the size of a football field once deployed. The idea is to break the system up into separate components that can be robotically assembled in space.
“By doing that, we eliminate trying to fit the whole system into one rocket fairing,” said Amanda Stark, a heat transfer engineer at NASA Langley and the principal investigator for MARVL. “In turn, that allows us to loosen up the design a little bit and really optimize it.”
This simple illustration shows MARVL’s main components, including its football field-sized heat dissipation system. Image Credit: NASA/Tim MarvelFolding the entire system up into a small enough payload to fit inside a rocket fairing isn’t really an option. Engineers have successfully folded other spacecraft into nosecones and then deployed them after release. The JWST’s mirror is probably the best example of that. But the JWST’s primary mirror is only 6.5 meters (21 ft and 4 inches) across. That’s far smaller than MARVL’s heat dissipation system, and it was still an elaborate challenge.
Making the heat dissipation system modular and assembling it in space with robots opens up new possibilities. The components could be launched into space in any order and in any combination that makes sense.
Space robotics is advancing and will play a larger and larger role as the future unfolds. The entire idea is an engineering challenge, but one that’s not that far out of reach. NASA’s Langley Research Centre has been working on these types of problems for decades.
Langley is a huge complex covering more than 700 acres that employs thousands of engineers, technicians, and scientists. It has made pioneering contributions to flight and spaceflight. The Centre played an important role in the development of the Apollo Lunar Module and contributed to other endeavours like the Hubble Space Telescope and the Viking Mars Lander. Space technology and research is one of their primary focuses.
This is an opportunity to produce a vehicle from the ground up that is designed to be launched in pieces and assembled in space.
“Existing vehicles have not previously considered in-space assembly during the design process, so we have the opportunity here to say, ‘We’re going to build this vehicle in space. How do we do it? And what does the vehicle look like if we do that?’ I think it’s going to expand what we think of when it comes to nuclear propulsion,” said Julia Cline, a mentor for the project in NASA Langley’s Research Directorate. Cline led the center’s participation in the Nuclear Electric Propulsion tech maturation plan development as a precursor to MARVL.
The Nuclear Electric Propulsion (NEP) system wasn’t the only one under consideration. NASA also considered the Nuclear Thermal Propulsion (NTP) system. They also considered a “quad-wing” design for the NEP system because it could be folded into the Space Launch System’s payload fairing. However, that system required a larger surface area, and the deployment systems in that design were heavy and complicated. It also required more propellant.
This illustration shows the basic design of the proposed quad-wing NEP system. Image Credit: From “ECI Modular Assembled Radiators for NEP VehicLes (MARVL), an Overview” by Stark et al. 2024.The Bi-Wing design has several advantages over the Quad-Wing design. It can be launched piece by piece in commercial launch vehicles without the need for the SLS. The rocket payload fairing doesn’t restrict the radiator size, and it avoids solar flux, which would inhibit cooling.
This illustration shows the MARVL NEP Bi-Wing design. It can be launched on commercial launch vehicles, needs less propellant, and has lightweight joints, among other things. Image Credit: NASA/Tim MarvelNASA gave the MARVL project team two years to develop the idea. By then, the team hopes to have a small-scale ground demonstration ready.
“One of our mentors remarked, ‘This is why I wanted to work at NASA, for projects like this,'” said Stark, “which is awesome because I am so happy to be involved with it, and I feel the same way.”
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