Navigating the harsh terrain of other rocky worlds has consistently been challenging. The Free Spirit campaign unfortunately failed in its goal to will the plucky Martian rover out of the morass it found itself in, despite two years of continual effort from some of the world’s best engineers. To combat this difficulty, other engineers have turned to alternative propulsion methods, and a team of researchers in the EU have done just that for their work on an autonomous mining robot. They decided to use an Archimedes screw as their primary propulsion method.
The team has already successfully tested various prototype iterations of their miniaturized mining robot. More recently have released a paper that detailed a mobility platform based on four individually controlled Archimedes screws that could be useful for more than just mining underground.
As with most engineering projects, they started with a computer model, which resulted in a CAD model that the team tested on different terrain. They weren’t the first ones to think of using an Archimedes screw as a driving mechanism. Existing research has pointed out that it is not the most efficient on some terrains. However, it can navigate almost all terrains to at least some degree.
The work described in the paper was part of the ROBOMINERS project, supported by the EU.Kinematics models are critical to the development of any robot, and one with a relatively obscure propulsion system is no exception. Since Archimedes screws can be modeled from any observational angle, coordinating the operation of each of the four independent screws to align correctly to the desired direction required some complex modeling that was eventually hosted as part of the control algorithm on board a computer seated on top of the mobile platform.
Another part of the control algorithm required the robot to understand how it was orientated, and to do that, the team developed an integrated network of sensors. These ranged from time of flight positioning systems, which allowed the robot to gauge the distance to an object, to force sensors on the screws themselves that would ensure they wouldn’t over-torque and burn out their drive motors.
Once the sensors were selected and the preliminary control code was written, it was time to put it to a real environmental test. The team built a physical prototype, partly out of 3D-printed parts, and set about moving it about on various surfaces. The drive system worked well on snow, sand, frozen ground, and mud. However, it was mainly used to traverse level surfaces rather than the more complicated slopes that it might encounter in some environments, such as Mars.
Fraser discusses how we might use robots to explore the Moon.That is not to say the system cannot adapt to slopes – just that there is more work to be done. ROBOMINERS, the EU project focused on building an autonomous mining robot, is looking to complete its final prototype soon, and the results of the drive platform testing shown in this latest paper will help contribute to that. Someday, it might contribute to a similar robot on the moon or Mars.
Learn More:
Gkliva et al – A Multi-Terrain Robot Prototype With Archimedean Screw Actuators: Design, Realization, Modeling, and Control
UT – NASA Tests a Robotic Snake That Could Explore Other Worlds
UT – Snake Rovers Might be the Best Way to Explore the Surface and Tunnels on Mars
UT – NASA Redoubling Efforts to Contact Spirit
Lead Image:
Prototype of the screw-driven robot on leafy ground.
Credit – Gkliva et al.
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Mars has been a fascination to us for centuries. Early observations falsely gave impressions of an intelligent civilisation but early visiting probes revealed a stark, desolate world. Underneath the surface is a few metres of water ice and a recent study by NASA suggests sunlight could reach the layer. If it does, it may allow photosynthesis in the meltwater. On Earth this actually happened and biologists have found similar pools teeming with life.
The exploration of Mars by space probes began in the 1960’s. It began with the Soviet Union Mars 1 and NASA’s Mariner mission and was soon followed by the well known Viking landers in 1976. They were the first missions to test surface material for signs of life. The Mars Pathfinder mission took along the Sojourner rover and was followed by Spirit and Opportunity rovers after the turn of the century. Curiosity rover was among the latest of the visitors along with Perseverance and China’s Tianwen-1. The focus of later missions has been the hunt for water and analysis of the climate and geology of the planet. This was not only to understand the conditions as the planet evolved but to pave the way for human exploration.
The Viking 1 lander was the first to capture a real selfie. This is a mosaic of high-resolution images of Viking 1 at Chryse Planitia. Image Credit: NASA/JPL.To date, there has been no evidence of life on Mars. The question has intrigued us for decades though. Of all the planets in the Solar System, Mars is the most likely place to have once harboured primitive life, chiefly due to the discovery of liquid water in the distant past. Evidence of ancient dried river beds has been found across the planet with mineral deposits indicating that Mars was once warmer, wetter and potentially far more habitable. Even organic molecules have been discovered by the Curiosity and Perseverance rovers but researchers continue to hunt for evidence (past or present) of microbial life.
Mars, Credit NASAA team of researchers from NASA have published a paper articulating their use of computer modelling to help the search. They have shown that sunlight can shine through the Martian water ice, perhaps even enough for photosynthesis to occur in shallow pools of meltwater.
There are two types of ice on Mars, frozen water and frozen carbon dioxide. The study explored water ice which had mostly formed as snow had fallen on the surface during a Martian ice age millions of years ago. The team believe that the key to the study are the dust particles that obscure light reaching the deeper layers of ice. They suggest that sunlight will warm the dark dust more than surrounding ice and then cause ice to warm and melt. Some scientists believe that ice at the surface cannot melt due to the thin dry atmosphere causing it to turn straight to a gas. This won’t apply to the ice deeper in the surface layer.
Almost pure water ice is seen in the ejecta surrounding this impact crater (8 meters in diameter), which formed in 2008. The only reason we can see ice at the surface here is because this crater is so young. As time passes, the ice will all sublimate and no longer be present at the surface. Image Credit: High Resolution Imaging Science Experiment camera, NASA/JPL-Caltech/University of Arizona.Such a process has been observed on Earth where dust heats ice, melts and allows the dust to sink. Over time, the dust particles will stop sinking through the ice but still generate enough heat to melt the ice and create tiny voids. It is here that thriving ecosystems have been found hosting simple forms of life.
The paper published in Nature Communications Earth & Environment, suggests the dusty ice can produce enough light at depths up to 3 metres to allow photosynthesis to occur. The subsurface pools of meltwater are protected from evaporating by the ice above. It also provides some protection from radiation too providing a possibly habitable environment for simple forms of life. The authors suggest the areas would likely form in the Martian tropics between 30 and 60 degrees latitude in both hemispheres.
Source : Could Life Exist Below Mars Ice? NASA Study Proposes Possibilities
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NASA’s Jet Propulsion Lab has announced a second round of layoffs for 2024, this time laying off 325 people – about 5% of its workforce. The announcement was made on Nov. 12 in a memo sent to employees, which notes the layoffs could have been even larger. The last cut was made this past February, when 530 employees were let go. Part of the issues which forced the layoffs comes from the the possible cancelation of the Mars Sample Return mission. With the October 2024 launch of Europa Clipper, JPL doesn’t have a flagship mission in the pipeline right now.
As with the layoffs in February, the cuts have nothing to do with the individual performance; it’s all budget-related and an attempt to balance the books. NASA Headquarters passed on funding constraints in the current budget to JPL, and while JPL has tried to manage them, the results are the two rounds of difficult layoffs.
“This is a message I had hoped not to have to write,” JPL Director Laurie Leshin said in the memo sent to all staff members. “Despite this being incredibly difficult for our community, this number [of layoffs] is lower than projected a few months ago thanks in part to the hard work of so many people across JPL.”
Dr. Laurie Leshin has been the director of the Jet Propulsion Laboratory since May 2022. Credit: JPL.Leshin said the lab’s leadership has had to deal with “continued funding challenges” and an uncertain future as NASA has been juggling and reconsidering its priorities for deep space exploration. She noted that the reduction was spread across nearly all areas of JPL, including technical, project, business, and support areas to meet the available funding for Fiscal Year 2025. Leshin said that the outcome of the presidential election last week did not have any bearing on the layoffs.
“We have taken seriously the need to re-size our workforce, whether direct-funded (project) or funded on overhead (burden). With lower budgets and based on the forecasted work ahead, we had to tighten our belts across the board, and you will see that reflected in the layoff impacts,” Leshin wrote.
All employees were told to work from home today (Nov. 13) and everyone would receive an email whether their position was being eliminated or not. Leshin said JPL would offer “personalized support to our laid-off colleagues who are part of the workforce reduction, including offering dedicated time to discuss their benefits, and several other forms of assistance.”
Artist’s concept of a Europa Clipper mission. Credit: NASA/JPLThis second round of layoffs were not a surprise. During a recent town hall with employees, Leshin discussed the continued funding challenges and projections of what the potential impact on the JPL workforce could look like. She indicated her team had been working through multiple workforce scenarios to address the changes in funding, with the goal of minimizing adverse effects on JPL’s capabilities and workers. But despite their efforts, the conclusion was that this additional workforce reduction was inevitable.
After the layoffs today, JPL will be left with about 5,500 regular employees.
“These are painful but necessary adjustments that will enable us to adhere to our budget while continuing our important work for NASA and our nation,” JPL said in a statement.
On social media, JPL employees called the news “devastating,” and “awful.” Another said, “Can’t imagine the stress this will produce.”
But Leshin also said she believed this would be the last workforce reduction needed for the foreseeable future and that staffing levels at this point are now “stable and supportable.”
“While we can never be 100 percent certain of the future budget, we will be well positioned for the work ahead,” Leshin wrote. “This may not help much in this difficult moment, but I do want to be crystal clear with my thoughts and perspective. If we hold strong together, we will come through this, just as we have done during other turbulent times in JPL’s nearly 90-year history.”
Dare Mighty Things The “Dare Mighty Things” sign at JPL. Image by Nancy Atkinson.JPL has a long and storied history — “Dare Mighty Things” is the Lab’s motto — with the Lab’s origins dating back to the 1930s, when Caltech professor Theodore von Kármán oversaw pioneering work in rocket propulsion. In the 1960s, JPL began to develop robotic spacecraft to explore other worlds, beginning with the Ranger and Surveyor missions to the Moon, quickly followed by Mariner missions to Mercury, Venus and Mars. Now, missions and instruments built or managed by JPL have visited every planet in our Solar System as well as studying the Sun. The iconic Voyager missions have now entered interstellar space.
Despite the difficult layoffs, Leshin was hopeful for what’s to come for JPL.
“We are an incredibly strong organization—our dazzling history, current achievements, and relentless commitment to exploration and discovery position us well for the future,” she wrote.
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I passed these leaves on the way home, which immediately recalled this song about the waning of the year—and of life. And the most plaintive version, of course, is by Willie Nelson:
Will we ever understand how life got started on Earth? We’ve learned much about Earth’s long, multi-billion-year history, but a detailed understanding of how the planet’s atmospheric chemistry evolved still eludes us. At one time, Earth was atmospherically hostile, and its transition from that state to a planet teeming with life followed a complex path.
What made Earth so special? Research shows that while Earth is completely different from its neighbouring planets now, in the past, it shared many atmospheric characteristics with modern-day Venus and Mars. How did Earth turn out so different?
A better understanding of Earth’s atmospheric journey can help us understand some of the distant exoplanets we’ve detected. In the near future, new telescopes will be revealing more details of exoplanet atmospheres. Many puzzles await, and some of the solutions to understanding them could be found on ancient Earth.
Ancient Earth had a reducing atmosphere, which means that there was a lack of free oxygen. The atmosphere contained reducing gases like hydrogen and methane. These gases quickly react with oxygen and remove it from the atmosphere. Some of those same molecules also react with UV light, and the chemical reactions produce organic molecules.
While that’s a general outline of some aspects of ancient Earth’s atmosphere, there’s a lot of detail that needs to be constrained before a clearer picture emerges of Earth’s transformation.
Researchers at Tohoku University, the University of Tokyo, and Hokkaido University have developed a new model of atmospheric chemical reactions that sheds light on how Earth’s atmosphere evolved and how the first life may have arisen.
The research is “Self-Shielding Enhanced Organics Synthesis in an Early Reduced Earth’s Atmosphere.” It’s published in the journal Astrobiology, and Tatsuya Yoshida from Tohoku University is the lead author.
Before life could appear, Earth needed a good supply of important prebiotic molecules like formaldehyde (H2CO) and poisonous hydrogen cyanide (HCN). These molecules are critical because they can undergo a wide variety of reactions to produce the more complex molecules life requires. They produce amino acids, sugars, and nucleobases, which are the building blocks for DNA and RNA.
Research shows that a highly reduced atmosphere like ancient Earth’s is a candidate for producing these important prebiotic molecules, especially if it’s above a primordial ocean. Earth’s primordial ocean, or proto-ocean, was also much different from the modern ocean. Among other things, it was acidic because of volcanic gases. It was also hot.
Ancient Earth had hot, acidic oceans and a reducing atmosphere that lacked free oxygen. Image Credit: NASA/T.Pyle“Ancient Earth was nothing like our current home,” explains co-author Shungo Koyama, also from Tohoku University. “It was a much more hostile place; rich in metallic iron with an atmosphere containing hydrogen and methane.”
The Sun’s UV radiation bombarded ancient Earth unimpeded by an ozone layer, driving chemical reactions in the ancient Earth’s atmosphere, oceans, and crust.
That much is understood. But what scientists desire is a better understanding of all of the details. “However, the branching ratio between organic matter formation and oxidation remains unknown despite its significance on the abiotic chemical evolution of early Earth,” the authors explain.
The researchers developed a photochemical model for a reduced Earth’s atmosphere primarily containing H2 and CH4. Their model is based on one that’s been successfully applied to Jupiter’s atmosphere, the atmospheres of ancient and modern Mars, and runaway greenhouse atmospheres. The model considers 342 separate chemical reactions and also includes atmospheric hydrogen escape and atmospheric mixing.
The young Sun emitted more intense UV radiation than the modern Sun. The UV broke water molecules down into hydrogen and oxygen radicals. Radicals have one unpaired electron, which makes them chemically reactive. Much of the hydrogen escaped to space, while the oxygen did not.
Illustration of what the Sun may have been like 4 billion years ago. Scientists think that overall, the young Sun was fainter than it is now. But it was also more active and had a higher level of magnetic activity. That activity made the Sun emit more UV than it does now. Credit: NASA’s Goddard Space Flight Center/Conceptual Image LabThe oxygen radicals combined with methane led to the creation of organic molecules like HCN and H2CO.
Hydrocarbons, such as acetylene (C2H2) and methylacetylene (C3H4), were also present in the atmosphere. These chemicals absorbed some UV, shielding the lower atmosphere from photodissociation. “According to our results, UV absorptions by gaseous hydrocarbons such as C2H2 and C3H4 significantly suppress the H2O photolysis and following CH4 oxidation,” the authors explain. The atmospheric methane helped drive the production of organics.
That allowed organic molecules to accumulate into a prebiotic soup, which could’ve provided the building blocks for life.
“Accordingly, nearly half of initial CH4 possibly becomes converted to heavier organics along with deposition of prebiotically essential molecules such as HCN and H2CO on the surface of a primordial ocean for a geological timescale order of 10-100 Myr,” the authors write.
This diagram shows the evolution of Earth’s ancient atmosphere estimated by this study. Earth initially had a reducing atmosphere with lots of H2 and some CH4. Intense UV energy from the Sun split water into hydrogen and oxygen radicals, with much of the hydrogen escaping into space. CH4 that remains in the atmosphere is converted into organics. Earth loses its ancient CH4 and H2-rich atmosphere, the CH4 decomposes, and a layer of organics several hundred meters thick accumulates. Image Credit: Yoshida et al. 2024As time went on and the reduced atmosphere evolved, H2CO and HCN were continuously synthesized and accumulated in the ocean. H2CO and HCN are considered to be critical in prebiotic chemistry. According to these results, Earth’s early atmosphere was a major source of these important prebiotic molecules. They didn’t need to come from meteorites or comets.
The authors calculate that a layer of organic several hundred meters thick may have covered the ocean. “The continuous supply of these prebiotically important molecules could potentially lead to the synthesis of amino acids, nucleobases, sugars, and their polymers,” the researchers write.
“There may have been an accumulation of organics that created what was like an enriched soup of important building blocks. That could have been the source from which living things first emerged on Earth,” said lead author Yoshida.
The model shows that Earth’s early atmosphere was eerily similar to modern-day Mars and Venus. However, Earth evolved into a completely different world. How?
This research doesn’t explain it all. But it does deepen our understanding of the evolutionary track Earth followed.
The question becomes, is Earth unique? Or is it a common path that exoplanets in other Solar Systems can follow?
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