- What's New In Robotics This Week - 20.04.2018
-Manufacturing & Cobot Roundup
-IKEA-assembling bot (w/Robotiq grippers!)
-Universal Robots, Mitsubishi Electric, BMW
-US Army soft bots
-And much more!
Manufacturing & cobot roundup
An autonomous robot designed by mechanical engineers in NTU Singapore captured the attention of global media this week by successfully mastering a familiar assembly challenge --putting IKEA furniture together. The new system can assemble an IKEA chair (sans manual) in less than 21 minutes, including motion planning and part location.
According to The Verge, assembling IKEA furniture should become "a new benchmark for robot dexterity." We'll have update on this story very soon, as Robotiq's 2-Finger adaptive grippers are a key component of the system!
PBS has more...
Mitsubishi Electric showcased its new MELFA collaborative robot, which is designed to "cooperate with humans in industrial plants, and work around them, boosting productivity and enhancing plant flexibility."
Robot workstations equipped with RightHand Robotics' supply chain automation technology successfully picked up and placed 131,072 items over the duration of this year's MODEX show. Along the way, the firm set a world record with potentially "monumental" implications, ZDNet reported:
Even if you don't care how many times a team of small industrial robots can pick up and put down various objects during a trade show, the results speak to broader trends in automation that amount to a veritable revolution in how global commerce functions.
In an interview with India's Financial Express, Jurgen Von Hollen, President of leading cobot maker Universal Robots, spoke about the potential for cobots to act as a "third arm for the workforce." Universal Robots has doubled cobot deployments every year for the last three years in India and currently has some 400 cobots at work in the country.
Business Insider took a peek behind the scenes at BMW's Spartanburg, South Carolina plant, which produces 1,400 vehicles a day. 500 robots and 450 employees collaborate on each SUV...
Engineers from the University of Tokyo have developed a robot that can identify, collect, and manipulate two-dimensional nanocrystals to create designer nanomaterials. The robot manufactured "the most complex van der Waals heterostructure produced to date, with much less human intervention than the manual operations previously used." Such a bot could prove very useful in advanced electronics applications.
Caption: Robot for assembly of designer nanomaterials. Credit: 2018 Satoru Masubuchi, University of Tokyo.
Meanwhile, Xinhua reported that China's industrial output grew by 6.8 pct in Q1 and The New York Times reported that the rate of economic growth in Eastern Europe has led to severe labor shortages, so companies are "calling in the machines."
KUKA partner BACA Systems recently developed and installed two RS202 Robo SawJets based on the KUKA KR 210 robot...
According to the latest study by the Centre for European Economic Research Research, the rapid spread of industrial robots in Germany hasn’t made a dent in employment figures as "new tasks have been created for the workforce alongside [those] once performed by machines."
A Universal Robots UR10 cobot suspended from a linear rail is an integral part of this smart cell. The system was designed to reduce inspection cycle times and provide consistency in 3D scanning from one operator to the next....
The US Army Research Laboratory announced a joint research project with the University of Minnesota to design soft, squid-like, spineless robots for “covert maneuvering” in “highly congested and contested urban environments”.
Caption: (a) Schematic of a soft actuator device (left) and exploded view of the device and constituent material layers (right). (b) Schematic of depositing (3D printing) hydrogel on the surface of a silicone layer after surface treatment and under UV light exposure. (c) Printing of the ionic hydrogel on the passive layer after surface treatment (left), final 3D printed DEA (middle), and microstructure image of the device cross-section (right). (U.S. Army illustration)
Small and medium sized businesses have been challenged to develop a ‘lighter than air’ robot that can remotely inspect internal roof fixtures at a decommissioned nuclear site in the UK.
Melanie Moses, creator of NASA's Swarmathon competition was interviewed about her work...
Driven by an aging population and rising demand for medical services, Japan's industrial robot makers are "looking to apply their high-precision control technologies in health care, with remotely operated medical equipment and robotic walkers that assist people with restricted mobility," Nikkei Asian Review reported.
University of Guelph researcher, Meagan King, is exploring how robotic milking systems can be used to detect early signs of illness in cows...
Finally, experts from Imperial College London explored ten "grand challenges for the future of robotics."
I'll be back next week with more robotics news. Until then...
Five vids for Friday
1. University of Houston researchers have created a prototype adaptive, soft robot that could be used in medicine, rescue and defense.
2. Researchers are using cameras strapped to dogs to train deep learning algorithms how to navigate the world like a dog (H/T IEEE Spectrum).
4. Dr. Calum MacKellar, Director of Research of the Scottish Council on Human Bioethics, asked "Would it be ethical to create suffering robots?"
5. Patrick Anderson, a graduate student in the MED Lab at Vanderbilt University in the US is working on a multi-needle robot that could one day be used to perform lung surgery.
- Risk Assessment for the Robotiq 2-Finger Gripper
Assessing the risks of a collaborative robot is a complex process. It involves many different risks, probabilities, and – most importantly – devices. And it's sometimes hard to get all the safety data for each device.
In this article, we'll give you a few tips on evaluating our 2-Finger Gripper.
What is a risk assessment for collaborative robots?
Since you will need to know exactly what is a risk assessment and how to do it, I highly suggest that you read the following documents so we can talk the language.
How do you evaluate risk?
When analyzing risk, you need to evaluate each potential risk and rank them on a standardized scale.
We use four different factors to qualify a risk:
- Degree of Possible Harm (DPH)
- Possibility of Occurrence (PO)
- Possibility of Avoidance (PA)
- Frequency of Exposure (FE)
All these factors have different levels attached to them. Once each factor has been evaluated, we use this formula to obtain the hazard rating:
HR = DPH x PO x PA x FE.
The risk assessment template (that we linked to above) provides more details on the points accorded to different criteria. For example, Degree of Possible Harm is determined as follows.
Degree of Possible Harm (DPH):
0.5 Laceration/cut/mild ill health effect/minor burns
3 Fracture of minor bone – fingers, toes
5 Fracture of major bone – hand, arm, leg
8 Loss of 1 or 2 fingers/toes or major burns
11 Leg/hand amputation, partial loss of hearing or eye
15 Amputation of 2 legs/hands, total loss of hearing/sight in both ears/eyes
25 Critical injuries or permanent illness/condition/injury
40 Single Fatality
Taken from Pilz Hazard Rating; Risk Assessment eBook
If you need more information on what type of impact or force level will produce a certain injury, refer to the ISO/TS 15066 standard.
When all the criteria have been calculated for each risk, you can estimate whether the risk is acceptable, or a critical one that must be reduced.
Again the risk evaluation scale is available in the Risk Assessment for Collaborative Robot template. With that covered, let’s get into the details of the 2-Finger Gripper specifically.
What are the potential risks of the 2-Finger Gripper?
We have identified four main risks to using the Gripper:
- Crushing of a body part when the fingers are closing
- Crushing of a body part when the gripper is hitting a surface (semi-static impact)
- Transient impact during robot motion
- Entrapment of a body part in the open finger linkage
Transient impact vs. quasi-static impact
What's the hazard rating for each risk?
Here we'll try doing a risk evaluation for each identified risk.
However, as you might imagine, there are many more risks that could be involved. Proper risk assessments always have to consider all the different devices and actions of the robotic cell.
That being said, let’s proceed with our "mini" risk evaluation.
Crushing of a body part when the fingers are closing
This hazard is rated a negligible risk on the Pilz Hazard Rating.
Safe Pressure Level
Crushing of a body part when the gripper is hitting a surface
Note that in this case, the pressure level may be higher than the force level. You may need to calculate the area where the force is applied and translate it into pressure.
This hazard is rated a low risk on the Pilz Hazard Rating.
Transient impact during robot motion
In the ISO/TS 15066 we can see that the pain threshold is two times higher during a transient impact than during a quasi-static impact. That means that during a transient impact, the user can be hit with twice as much force as during a quasi-static impact and feel the same pain level. That being said, the degree of possible harm at a same force is a lot lower.
This hazard is rated a negligible risk on the Pilz Hazard Rating.
Entrapment of a body part in the open finger linkage
Entrapment in the mechanical linkage is quite hard to quantify in terms of injury or pain level. We will estimate that a small fracture can occur.
This hazard is rated a low risk on the Pilz Hazard Rating.
In order to reduce that risk, Robotiq offers protective covers that can cover all the open finger linkages. Use of these covers lowers the possibility of occurrence (PO) to Almost Impossible (0.05), which reduces the HR to 0.93.
Covers for the Robotiq 2-Finger Adaptive Robot Gripper
As you might have noticed, our analysis concludes that the 2-Finger Gripper presents no major risks. However, the risks we presented here are merely examples of what can happen – they are not an exclusive list.
There are plenty of other risks involved in using the Gripper and robot. Download our eBook to learn more about how to evaluate them.Read more »
- The Right Way to Design a Cobot Cell Layout
Designing a robotic cell layout can sometimes seem like a "dark art," but it doesn't have to be. Follow these four steps and you'll master the art in no time.
Cell layout is crucial aspect of a successful robotic cell. Get it wrong and you could seriously reduce the productivity gains that a collaborative robot (or "cobot') can bring. Get it right and you can increase your robot's productivity even further.
But what's the best way to lay out a cobot cell?
Should you just clamp the robot onto any old table, pile up a load of products, and press go?
It's a good idea to take the time to properly design the cell layout, using best practices from the Lean Robotics framework.
Why cell layout seems like a "dark art"
It's often hard to find much information on good cobot cell layouts. There's a simple reason why: since every cell is different, there are few hard and fast rules that will apply to all of them.
Experienced robot integrators have spent years designing cells. They develop an intuitive understanding of what makes an effective layout. To the rest of us, this makes cell layout design seem confusing and mysterious – like a "dark art."
But it doesn't have to be this way. Cell layout can be quite straightforward when you approach it the right way.
I like to think of the cell layout like a kitchen.
A well-laid-out cell is like the kitchen of a professional chef. On the surface, it might look like any other kitchen. However, a chef will ensure that their utensils, ingredients and work spaces are all located in the optimal place for the chef to do their work.
The chef can move quickly and easily around the space. They're able to locate everything they need within moments. As a result, they can produce a professional meal in minutes.
A poorly laid-out cell is like my kitchen at home. On the surface, it's a nice enough kitchen that looks tidy and organized. However, the utensils, ingredients, and work spaces are not well-optimized.
I have to continually move back and forth around the kitchen, rummaging through drawers for utensils and searching for missing items. As a result, I can produce a decent meal… but it takes ages!
If I want to improve the layout of my kitchen, I should start thinking like a professional chef.
Similarly, if you want to design a better cobot cell, you should start thinking like a collaborative robot.
Ask yourself: where should all the tools, workpieces, and work spaces be placed so the cobot can work most efficiently?
How to design a cobot cell in four steps
There are four steps to designing a cell layout – the first three of which should be done before you even think about the physical layout.
(These three steps take place during the Design phase of any cobot project, and are explained in detail in the Lean Robotics book.)
The four cell layout design steps are:
1. Analyze and define the manual task map
Most collaborative robot applications start off as a manual operation. The idea here is to use your manual task as a starting point for the robotic cell.
You should begin by analyzing how human workers are currently performing the task. The Lean Robotics framework defines this process in seven steps:
- Identify the cell's "customer"—Start your analysis at the end. The cell's customer is considered to be the next cell along in your process.
- Define the valuable output—What input does the customer cell need? This is your cell's output.
- Define the input—What input does your cell need from the previous cells in the process?
- Describe the manual process—Here, you should list all the steps that the human operators perform. This list describes the tasks that you'll be trying to accomplish later with the robot.
- Document the flow of information—How does information get passed to and from the cell? How will this flow of information be affected by the introduction of a robot?
- Measure cell KPIs—Set goals for the cell and determine how to measure them.
- Summarize the manual task map—Gather all the information you've found in a visual map.
This process, which is described in detail in the Lean Robotics book, gives you a lot of information you can use to build your robotic cell.
2. Begin the robotic task map
Next, you want to "translate" your manual task so it can be performed by a robot. To do so, you'll create a robotic task map. Like the manual map, there are seven steps to creating the robotic task map.
You might think that you can't define the task map without first designing the layout… and you're right. However, the problem is you also can't design the layout until you've first defined the task map!
This leaves us in a bit of a deadlock.
The solution is to develop the two in tandem. Start by defining your high-level task map. Then, form the detailed task map as you begin to design the layout.
3. Define the high-level task map
The high-level task map defines the physical components you will need. These include the robot itself, tooling, safety measures, sensors, and software.
Define these high-level components before you begin to draw up the physical blueprint of the cell.
4. Design the layout (and update the task map)
At last, you're ready to design the layout.
I recommend starting by physically walking yourself through the task, using your hand and arm in place of the robot. This step only takes a few minutes, but it can shave hours off your design time.
In fact, this is one of the great insights that came out of our 24 Hour Challenge at the Robotiq User Conference last year! The winning team found that walking through the task first saved them a lot of time and effort down the line.
Next, decide where the robot, objects, and work spaces need to be located so the robot can perform most efficiently.
Pay attention to the physical properties of the robot, especially its "reach" – this will determine how far away objects can be from the robot.
Once you've got a good idea of the cell layout in your mind, sketch it on paper.
Finally, revise your plan. Try to keep the distances that the robot has to travel to a minimum. This will lower the task's cycle time and increase the robot's productivity. You should also consider alternative cell layouts, just in case there's a way to make your cell better that you didn't think of before.
By following this straightforward process, you'll be well on your way to mastering the not-so-dark art of cobot cell layout.
Interested in trying it out? Download a task mapping template at leanrobotics.org.Read more »
NASA Breaking News
- NASA Invites Media to Swearing-In of New Agency AdministratorMedia are invited to see Vice President Mike Pence swear in Jim Bridenstine as NASA’s new administrator at 2:30 p.m. EDT Monday, April 23, at the agency’s headquarters in Washington. The ceremony will air live on NASA Television and the agency’s website. Read more »
- NASA Awards Construction Contract for Instrument Development FacilityNASA has awarded a contract to the Manhattan Construction Company, of Arlington Virginia, for the construction of the Instrument Development Facility at the agency’s Goddard Space Flight Center in Greenbelt, Maryland. Read more »
- NASA Astronauts on Space Station to Speak with Students from Florida, TexasStudents from Coral Gables, Florida, and the Texas Gulf Coast will talk with astronauts aboard the International Space Station next week as part of NASA’s Year of Education on Station. Read more »
- The Challenges of an Alien Spaceflight Program: Escaping Super Earths and Red Dwarf Stars
Since the beginning of the Space Age, humans have relied on chemical rockets to get into space. While this method is certainly effective, it is also very expensive and requires a considerable amount of resources. As we look to more efficient means of getting out into space, one has to wonder if similarly-advanced species on other planets (where conditions would be different) would rely on similar methods.
Harvard Professor Abraham Loeb and Michael Hippke, an independent researcher affiliated with the Sonneberg Observatory, both addressed this question in two recently–released papers. Whereas Prof. Loeb looks at the challenges extra-terrestrials would face launching rockets from Proxima b, Hippke considers whether aliens living on a Super-Earth would be able to get into space.
The papers, tiled “Interstellar Escape from Proxima b is Barely Possible with Chemical Rockets” and “Spaceflight from Super-Earths is difficult” recently appeared online, and were authored by Prof. Loeb and Hippke, respectively. Whereas Loeb addresses the challenges of chemical rockets escaping Proxima b, Hippke considers whether or not the same rockets would able to achieve escape velocity at all.
For the sake of his study, Loeb considered how we humans are fortunate enough to live on a planet that is well-suited for space launches. Essentially, if a rocket is to escape from the Earth’s surface and reach space, it needs to achieve an escape velocity of 11.186 km/s (40,270 km/h; 25,020 mph). Similarly, the escape velocity needed to get away from the location of the Earth around the Sun is about 42 km/s (151,200 km/h; 93,951 mph).
As Prof. Loeb told Universe Today via email:
“Chemical propulsion requires a fuel mass that grows exponentially with terminal speed. By a fortunate coincidence the escape speed from the orbit of the Earth around the Sun is at the limit of attainable speed by chemical rockets. But the habitable zone around fainter stars is closer in, making it much more challenging for chemical rockets to escape from the deeper gravitational pit there.”
As Loeb indicates in his essay, the escape speed scales as the square root of the stellar mass over the distance from the star, which implies that the escape speed from the habitable zone scales inversely with stellar mass to the power of one quarter. For planets like Earth, orbiting within the habitable zone of a G-type (yellow dwarf) star like our Sun, this works out quite while.
Unfortunately, this does not work well for terrestrial planets that orbit lower-mass M-type (red dwarf) stars. These stars are the most common type in the Universe, accounting for 75% of stars in the Milky Way Galaxy alone. In addition, recent exoplanet surveys have discovered a plethora of rocky planets orbiting red dwarf stars systems, with some scientists venturing that they are the most likely place to find potentially-habitable rocky planets.
Using the nearest star to our own as an example (Proxima Centauri), Loeb explains how a rocket using chemical propellant would have a much harder time achieving escape velocity from a planet located within it’s habitable zone.
“The nearest star to the Sun, Proxima Centauri, is an example for a faint star with only 12% of the mass of the Sun,” he said. “A couple of years ago, it was discovered that this star has an Earth-size planet, Proxima b, in its habitable zone, which is 20 times closer than the separation of the Earth from the Sun. At that location, the escape speed is 50% larger than from the orbit of the Earth around the Sun. A civilization on Proxima b will find it difficult to escape from their location to interstellar space with chemical rockets.”
Hippke’s paper, on the other hand, begins by considering that Earth may in fact not be the most habitable type of planet in our Universe. For instance, planets that are more massive than Earth would have higher surface gravity, which means they would be able to hold onto a thicker atmosphere, which would provide greater shielding against harmful cosmic rays and solar radiation.
In addition, a planet with higher gravity would have a flatter topography, resulting in archipelagos instead of continents and shallower oceans – an ideal situation where biodiversity is concerned. However, when it comes to rocket launches, increased surface gravity would also mean a higher escape velocity. As Hippke indicated in his study:
“Rockets suffer from the Tsiolkovsky (1903) equation : if a rocket carries its own fuel, the ratio of total rocket mass versus final velocity is an exponential function, making high speeds (or heavy payloads) increasingly expensive.”
For comparison, Hippke uses Kepler-20 b, a Super-Earth located 950 light years away that is 1.6 times Earth’s radius and 9.7 times it mass. Whereas escape velocity from Earth is roughly 11 km/s, a rocket attempting to leave a Super-Earth similar to Kepler-20 b would need to achieve an escape velocity of ~27.1 km/s. As a result, a single-stage rocket on Kepler-20 b would have to burn 104 times as much fuel as a rocket on Earth to get into orbit.
To put it into perspective, Hippke considers specific payloads being launched from Earth. “To lift a more useful payload of 6.2 t as required for the James Webb Space Telescope on Kepler-20 b, the fuel mass would increase to 55,000 t, about the mass of the largest ocean battleships,” he writes. “For a classical Apollo moon mission (45 t), the rocket would need to be considerably larger, ~400,000 t.”
While Hippke’s analysis concludes that chemical rockets would still allow for escape velocities on Super-Earths up to 10 Earth masses, the amount of propellant needed makes this method impractical. As Hippke pointed out, this could have a serious effect on an alien civilization’s development.
“I am surprised to see how close we as humans are to end up on a planet which is still reasonably lightweight to conduct space flight,” he said. “Other civilizations, if they exist, might not be as lucky. On more massive planets, space flight would be exponentially more expensive. Such civilizations would not have satellite TV, a moon mission, or a Hubble Space Telescope. This should alter their way of development in certain ways we can now analyze in more detail.”
Both of these papers present some clear implications when it comes to the search for extra-terrestrial intelligence (SETI). For starters, it means that civilizations on planets that orbit red dwarf stars or Super-Earths are less likely to be space-faring, which would make detecting them more difficult. It also indicates that when it comes to the kinds of propulsion humanity is familiar with, we may be in the minority.
“This above results imply that chemical propulsion has a limited utility, so it would make sense to search for signals associated with lightsails or nuclear engines, especially near dwarf stars,” said Loeb. “But there are also interesting implications for the future of our own civilization.”
“One consequence of the paper is for space colonization and SETI,” added Hippke. “Civs from Super-Earths are much less likely to explore the stars. Instead, they would be (to some extent) “arrested” on their home planet, and e.g. make more use of lasers or radio telescopes for interstellar communication instead of sending probes or spaceships.”
However, both Loeb and Hippke also note that extra-terrestrial civilizations could address these challenges by adopting other methods of propulsion. In the end, chemical propulsion may be something that few technologically-advanced species would adopt because it is simply not practical for them. As Loeb explained:
“An advanced extraterrestrial civilization could use other propulsion methods, such as nuclear engines or lightsails which are not constrained by the same limitations as chemical propulsion and can reach speeds as high as a tenth of the speed of light. Our civilization is currently developing these alternative propulsion technologies but these efforts are still at their infancy.”
One such example is Breakthrough Starshot, which is currently being developed by the Breakthrough Prize Foundation (of which Loeb is the chair of the Advisory Committee). This initiative aims to use a laser-driven lightsail to accelerate a nanocraft up to speeds of 20% the speed of light, which will allow it to travel to Proxima Centauri in just 20 years time.
Hippke similarly considers nuclear rockets as a viable possibility, since increased surface gravity would also mean that space elevators would be impractical. Loeb also indicated that the limitations imposed by planets around low mass stars could have repercussions for when humans try to colonize the known Universe:
“When the sun will heat up enough to boil all water off the face of the Earth, we could relocate to a new home by then. Some of the most desirable destinations would be systems of multiple planets around low mass stars, such as the nearby dwarf star TRAPPIST-1 which weighs 9% of a solar mass and hosts seven Earth-size planets. Once we get to the habitable zone of TRAPPIST-1, however, there would be no rush to escape. Such stars burn hydrogen so slowly that they could keep us warm for ten trillion years, about a thousand times longer than the lifetime of the sun.”
But in the meantime, we can rest easy in the knowledge that we live on a habitable planet around a yellow dwarf star, which affords us not only life, but the ability to get out into space and explore. As always, when it comes to searching for signs of extra-terrestrial life in our Universe, we humans are forced to take the “low hanging fruit approach”.
Basically, the only planet we know of that supports life is Earth, and the only means of space exploration we know how to look for are the ones we ourselves have tried and tested. As a result, we are somewhat limited when it comes to looking for biosignatures (i.e. planets with liquid water, oxygen and nitrogen atmospheres, etc.) or technosignatures (i.e. radio transmissions, chemical rockets, etc.).
As our understanding of what conditions life can emerge under increases, and our own technology advances, we’ll have more to be on the lookout for. And hopefully, despite the additional challenges it may be facing, extra-terrestrial life will be looking for us!
Professor Loeb’s essay was also recently published in Scientific American.
The post The Challenges of an Alien Spaceflight Program: Escaping Super Earths and Red Dwarf Stars appeared first on Universe Today.Read more »
- This Meteorite is One of the Few Remnants from a Lost Planet that was Destroyed Long Ago
What if our Solar System had another generation of planets that formed before, or alongside, the planets we have today? A new study published in Nature Communications on April 17th 2018 presents evidence that says that’s what happened. The first-generation planets, or planet, would have been destroyed during collisions in the earlier days of the Solar System and much of the debris swept up in the formation of new bodies.
This is not a new theory, but a new study brings new evidence to support it.
The evidence is in the form of a meteorite that crashed into Sudan’s Nubian Desert in 2008. The meteorite is known as 2008 TC3, or the Almahata Sitta meteorite. Inside the meteorite are tiny crystals called nanodiamonds that, according to this study, could only have formed in the high-pressure conditions within the growth of a planet. This contrasts previous thinking around these meteorites which suggests they formed as a result of powerful shockwaves created in collisions between parent bodies.
“We demonstrate that these large diamonds cannot be the result of a shock but rather of growth that has taken place within a planet.” – study co-author Philippe Gillet
Models of planetary formation show that terrestrial planets are formed by the accretion of smaller bodies into larger and larger bodies. Follow the process long enough, and you end up with planets like Earth. The smaller bodies that join together are typically between the size of the Moon and Mars. But evidence of these smaller bodies is hard to find.
One type of unique and rare meteorite, called a ureilite, could provide the evidence to back up the models, and that’s what fell to Earth in the Nubian Desert in 2008. Ureilites are thought to be the remnants of a lost planet that was formed in the first 10 million years of the Solar System, and then was destroyed in a collision.
Ureilites are different than other stony meteorites. They have a higher component of carbon than other meteorites, mostly in the form of the aforementioned nanodiamonds. Researchers from Switzerland, France and Germany examined the diamonds inside 2008 TC3 and determined that they probably formed in a small proto-planet about 4.55 billion years ago.
Philippe Gillet, one of the study’s co-authors, had this to say in an interview with Associated Press: “We demonstrate that these large diamonds cannot be the result of a shock but rather of growth that has taken place within a planet.”
According to the research presented in this paper, these nanodiamonds were formed under pressures of 200,000 bar (2.9 million psi). This means the mystery parent-planet would have to have been as big as Mercury, or even Mars.
The key to the study is the size of the nanodiamonds. The team’s results show the presence of diamond crystals as large as 100 micrometers. Though the nanodiamonds have since been segmented by a process called graphitization, the team is confident that these larger crystals are there. And they could only have been formed by static high-pressure growth in the interior of a planet. A collision shock wave couldn’t have done it.
But the parent body of the ureilite meteorite in the study would have to have been subject to collisions, otherwise where is it? In the case of this meteorite, a collision and resulting shock wave still played a role.
The study goes on to say that a collision took place some time after the parent body’s formation. And this collision would have produced the shock wave that caused the graphitization of the nanodiamonds.
The key evidence is in what are called High-Angle Annular Dark-Field (HAADF) Scanning Transmission Electron Microscopy (STEM) images, as seen above. The image is two images in one, with the one on the right being a magnification of a part of the image on the left. On the left, dotted yellow lines indicate areas of diamond crystals separate from areas of graphite. On the right is a magnification of the green square.
The inclusion trails are what’s important here. On the right, the inclusion trails are highlighted with the orange lines. They clearly indicate inclusion lines that match between adjacent diamond segments. But the inclusion lines aren’t present in the intervening graphite. In the study, the researchers say this is “undeniable morphological evidence that the inclusions existed in diamond before these were broken into smaller pieces by graphitization.”
To summarize, this supports the idea that a small planet between the size of Mercury and Mars was formed in the first 10 million years of the Solar System. Inside that body, large nanodiamonds were formed by high-pressure growth. Eventually, that parent body was involved in a collision, which produced a shock wave. The shock wave then caused the graphitization of the nanodiamonds.
It’s an intriguing piece of evidence, and fits with what we know about the formation and evolution of our Solar System.
- A large planetary body inferred from diamond inclusions in a ureilite meteorite
- Study: Diamond from the sky may have come from ‘lost planet’
The post This Meteorite is One of the Few Remnants from a Lost Planet that was Destroyed Long Ago appeared first on Universe Today.Read more »
- Musk Says that SpaceX will use a Giant Party Balloon to Bring an Upper Stage Back. Wait, what?
When Elon Musk of SpaceX tweets something interesting, it generates a wave of excitement. So when he tweeted recently that SpaceX might be working on a way to retrieve upper stages of their rockets, it set off a chain of intrigued responses.
SpaceX will try to bring rocket upper stage back from orbital velocity using a giant party balloon
— Elon Musk (@elonmusk) April 15, 2018
SpaceX has been retrieving and reusing their lower stages for some time now, and it’s lowered the cost of launching payloads into space. But this is the first hint that they may try to do the same with upper stages.
Twitter responders wanted to know exactly what SpaceX has in mind, and what a “giant party balloon” might be. Musk hasn’t elaborated yet, but one of his Twitter followers had something interesting to add.
Quinn Kupec, a student at the University of Maryland’s James Clark School of Engineering tweeted to Musk:
If you're proposing what I think you are, an ultra low ballistic entry coefficient decelerator, then you and @SpaceX should come see what we have at the @UofMaryland . We've been working on this for awhile and just finished some testing pic.twitter.com/nJBvyUnzaK
— Quinn Kupec (@QuinnKupec) April 16, 2018
Universe Today contacted Mr. Kupec to see if he could help us understand what Musk may have been getting at. But first, a little background.
An “ultra low ballistic entry coefficient decelerator” is a bit of a mouthful. The ballistic coefficient measures how well a vehicle can overcome air resistance in flight. A high ballistic coefficient means a re-entry vehicle would not lose velocity quickly, and would reach Earth at high speeds. An ultra low ballistic entry coefficient decelerator would lose speed quickly, meaning that a vehicle would be travelling at low, subsonic speeds before reaching the ground.
To recover an upper stage booster, low speeds are desirable, since they generate less heat. But according to Kupec, there’s another problem that must be overcome.
“What happens when these things slow down to landing velocities? If your center of gravity is offset significantly behind your center of drag, as would be the case with a returning upper stage, it can get unstable. If the center of gravity of the re-entry vehicle is too high, it can become inverted, which is obviously not desirable.”
So the trick is to lower the speed of the re-entry vehicle to the point where the heat generated by reentry isn’t damaging the booster, and to do it without causing the vehicle to invert or otherwise become unstable. This isn’t a problem for the main stage boosters that SpaceX now routinely recovers; they have their own retro-rockets to guide their descent and landing. But for the upper stage boosters, which reach orbital velocities, it’s an obstacle that has to be overcome.
“My research is specifically focused on how high you can push the center of gravity and still maintain the proper flight configuration,” said Kupec.
But what about the “giant party balloon” that Musk tweeted about?
Musk could be referring, in colorful terms, to what’s called a ballute. The word is a combination of the words balloon and parachute. They were invented in the 1950’s by Goodyear Aerospace. They can arrest the descent of entry vehicles and provide stability during the descent.
“…the balloon would have to be 120 ft. in diameter, and made of a high-temperature fabric…” – Professor Dave Akin, University of Maryland
Universe Today contacted Professor Dave Akin of the University of Maryland for some insight into Musk’s tweet. Professor Akin has been working on reentry systems for over 2 decades.
In an e-mail exchange, Professor Akin told us, “There have been concepts proposed for deploying a large balloon on a cable that is towed behind you on entry. The balloon lowers your ballistic coefficient, which means you decelerate higher in the atmosphere and the heat load is less.” So the key is to scrub your speed before you get closer to Earth, where the atmosphere is thicker and generates more heat.
But according to Professor Akin, this won’t necessarily be easy to do. “To get the two orders of magnitude reduction in ballistic coefficient that Elon has been talking about the balloon would have to be 120 ft. in diameter, and made of a high-temperature fabric, so it’s not going to be all that easy.”
But Musk’s track record shows he doesn’t shy away from things that aren’t easy.
Retrieving upper rocket stages isn’t all about lowering launch costs, it’s also about space junk. The European Space Agency estimates that there are over 29,000 pieces of space junk orbiting Earth, and some of that junk is spent upper stage boosters. There have been some collisions and accidents already, with some satellites being pushed into different orbits. In 2009, the Iridium 33 communications satellite and the defunct Russian Cosmos 2251 communications satellite collided with each other, destroying both. If SpaceX can develop a way to retrieve its upper stage boosters, that means less space junk, and fewer potential collisions.
There’s a clear precedent for using balloons to manage reentry. With people like Professor Akin and Quinn Kupec working on it, SpaceX won’t have to reinvent the wheel. But they’ll still have a lot of work to do.
Musk tweeted one other thing shortly after his “giant party balloon” tweet:
And then land on a bouncy house
— Elon Musk (@elonmusk) April 16, 2018
No word yet on what that might mean.
Elon Musk’s “giant party balloon” tweet: https://twitter.com/elonmusk/status/985655249745592320
Quinn Kupec’s tweet: https://twitter.com/QuinnKupec/status/985736260827471872
The post Musk Says that SpaceX will use a Giant Party Balloon to Bring an Upper Stage Back. Wait, what? appeared first on Universe Today.Read more »
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