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  • richardmitnick 12:06 pm on July 1, 2021 Permalink | Reply
    Tags: "Q&A- How we’re gearing up to deflect asteroids that might cause Earth considerable damage", , Dr Naomi Murdoch, , , NASA Dart Mission   

    From Horizon The EU Research and Innovation Magazine : “Q&A- How we’re gearing up to deflect asteroids that might cause Earth considerable damage” 

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    From Horizon The EU Research and Innovation Magazine

    06 April 2021 [Why now!! This just showed up in social media.]
    Natalie Grover

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    “Asteroids hold clues about how our solar system formed. Their physical makeup and composition can also help answer the big question of how life emerged”, tells Dr Naomi Murdoch, planetary scientist specialised in the geophysical evolution of asteroids at the French aeronautics and space institute National Higher School of Mechanics and Aerotechnics [ISAE-ENSMA // École Nationale Supérieure de Mécanique et d’Aérotechnique | Le site de l’école ISAE-ENSMA situé au Futuroscope de Poitiers. (FR). Image credit – Naomi Murdoch.

    Asteroids — the bits and pieces left over from the formation of the inner planets — are a source of great curiosity for those keen to learn about the building blocks of our solar system, and to probe the chemistry of life.

    Humans are also considering mining asteroids for metals, but one of the crucial reasons scientists study this ancient space rubble is planetary defense, given the potential for space debris to cause Earth harm.

    Accordingly, NASA is planning a 2022 planetary defense mission that involves sending a spacecraft to crash into a near-Earth asteroid in an effort to check whether it could be deflected were it on a collision course with Earth.

    Dr Naomi Murdoch — a planetary scientist at the French aeronautics and space institute ISAE-SUPAERO, who specialises in the geophysical evolution of asteroids — is part of a follow-on mission planned by the European Space Agency [Agence spatiale européenne][Europäische Weltraumorganisation](EU).

    She tells Horizon about the mission will characterise the asteroid after impact to obtain data that will inform strategies designed to address any threatening asteroids that might come Earth’s way.

    But are we in any real danger of being wiped out by a big rocky remnant? Not really, but some asteroids can cause considerable damage, which is why we’re shoring up our defences here on Earth, she suggests.

    What makes asteroids interesting?

    Asteroids hold clues about how our solar system formed. Their physical makeup and composition can also help answer the big question of how life emerged.

    How many have we identified – and what are they made of?

    So far, we have identified more than a million asteroids, but there are tens, if not hundreds of millions out there that we don’t know about. This is because unlike stars, asteroids don’t emit a light of their own, they only reflect sunlight, so many of the smaller ones are difficult to spot.

    What they are made of depends on where they were formed in the solar system. The ones that formed closest to the sun have borne the brunt of the heat, losing material that could have been really interesting to study. But the most common ones are those that formed furthest away from the sun: the C (carbonaceous)-type, likely consisting of clay and silicate rocks, are among the most ancient objects in the solar system but are hard to detect because they are relatively dark in colour.

    Then there are brighter options. The M (metallic)-type, composed mainly of metallic iron, largely inhabit the asteroid belt’s middle section. (The asteroid belt lies roughly between Mars and Jupiter). The S (stony)-type, comprising silicate materials and nickel-iron, are most commonly found in the inner asteroid belt.

    Most meteorites (a small piece of an asteroid or comet that survives the journey across Earth’s atmosphere) found on Earth are either metallic or stony. It is less likely that the carbonaceous type will be found on the ground, unless the asteroids were quite large because they have to survive our planet’s atmosphere without completely burning up. Basically, the types of meteorites that we find on the ground are not necessarily representative of the type of asteroids that would even hit our atmosphere.

    So what kind of asteroid are scientists wary of in terms of the danger they pose to our planet?

    Any asteroid size could in principle, hit us, but the largest asteroids are easy to detect — we’ve identified the vast majority of them and they’re not risky. There are many, many more small asteroids than there are large ones, and because they’re small, they’re really difficult to detect and difficult to follow. We have to look for them several times in order to pinpoint their orbit to know where they’re going to be in space.

    What we focus on are those (small asteroids) in the 100-to-500-metre size range. This size range is probably the most dangerous because they could still cause a large amount of damage on Earth, for example on a regional and national scale. But we don’t know yet where they all are, which is why this is the key size range for planetary defence, because there’s a risk of discovering one day that one we didn’t know existed is coming towards us.

    Space scientists are trying to improve our ability to detect these smaller asteroids, then assess whether they are threats, and finally, if need be, (we try to) deflect the object.

    As part of the NEO-MAPP project, we are helping prepare for these planetary defence missions by improving space instruments that are linked to measuring properties of the surface, the subsurface and the internal structure of asteroids, because it’s these parameters that will govern whether a deflection mission is successful or not. Another objective is to develop a better understanding of landing on asteroids, of the consequences of their low gravity environment, and how to interpret data recorded during surface interactions.

    Once you’ve detected an asteroid you want to explore, how do you go about landing on one?

    Before the first space missions, many people thought that asteroids were just boring lumps of rock, but we started to realise that they were actually a lot more interesting. They have their own evolutionary history, which is really important to understand the solar system in general.

    The only way to really probe the mechanical and physical properties of an asteroid is to touch and interact directly with it, but we don’t have a good understanding of the actual surface of asteroids, which harbour a low-gravity environment. It’s a really exotic place, typically covered by granular material like sand, rocks, boulders, depending on the type of asteroid and its size. And this granular material, in that low gravity environment, appears to behave much more like a fluid than the same material would behave on Earth.

    As a result, previous missions have had varying degrees of landing success so we are now studying landing behaviour in gravitational conditions similar to those on asteroids.

    You are part of the European Space Agency’s Hera mission, which will follow-on from NASA’s DART mission to a binary asteroid system. What are these missions hoping to achieve?

    DART is an upcoming planetary defence mission designed to collide with a smaller asteroid moon, called Dimorphos, orbiting with the near-Earth asteroid Didymos. The idea is to test whether Dimorphos’s orbit can be deflected. In the days following, we’ll know whether the deflection was successful or not. Then, Hera will survey and characterise the asteroid pair and the resulting crater.

    The main Hera spacecraft will not touch the surface, and will perform all of the investigations in orbit around the asteroids. However, mini satellites called cubesats will land on the moon. One, for instance, will orbit and study the asteroid (the main instrument is a radar for looking inside it), and then it will descend to the surface. The landing part of the mission is ‘bonus science’ (not necessary to achieve the mission goals), but extremely interesting in order to characterise the physical properties of the asteroid.

    The idea behind these missions is to test a key deflection method and to understand the target. Although Dimorphos is not a threat to Earth, it is a size that is roughly in line with potentially threatening asteroids. What we want to do is have a well-characterised, large-scale experiment that we can use to extrapolate to any potential asteroid threats. In order to do that we need to learn about our targets, including their form, mass density, the impact crater size and the level of debris generated upon collision.

    By measuring the physical properties and characterising the target in detail we can calibrate our numerical (impact) models. If one day a potentially dangerous asteroid comes our way, we can use these models to predict what may happen if we try to deflect it.

    Another feature of Hera is the plan to take a look inside the moon. I think it’s going to be extremely exciting to see what’s in there, because that’s going to tell us a lot about the history of the asteroid-moon pair.

    So we’re gearing up to tackle any asteroids that might cause Earth some damage. But how likely are we to be wiped out completely by an asteroid?

    Small asteroids, including pieces tiny enough to be called space dust, hit our atmosphere every day — that is what shooting stars are. The probability of an asteroid causing large-scale damage is very small. That 100-to-500-metre size range is the most threatening range — so that’s what scientists are working on at the moment.

    Overall, we can all sleep soundly knowing that it is extremely unlikely that we’re going to be wiped out by an asteroid.

    See the full article here .


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  • richardmitnick 12:24 pm on September 16, 2020 Permalink | Reply
    Tags: "Hera: ESA’s planetary defence mission", Astrophysicist and and Queen guitarist Brian May tells the story of the ESA mission that would be humanity's first-ever spacecraft to visit a double asteroid., , , NASA Dart Mission   

    From European Space Agency – United Space in Europe: “Hera: ESA’s planetary defence mission” 

    ESA Space For Europe Banner

    From European Space Agency – United Space in Europe

    Hera will show us things we’ve never seen before. Astrophysicist and and Queen guitarist Brian May tells the story of the ESA mission that would be humanity’s first-ever spacecraft to visit a double asteroid.

    Brian May, astrophysicist and Queen Guitarist.

    The asteroid system – named Didymos – is typical of the thousands that pose an impact risk to our planet, and even the smaller of the two would be big enough to destroy an entire city if it were to collide with Earth.

    Hera will help ESA to find out if it would be possible to deflect such an asteroid on a collision course with Earth. The mission will revolutionise our understanding of asteroids and how to protect ourselves from them, and therefore could be crucial for saving our planet.

    First, NASA will crash its DART spacecraft into the smaller asteroid – known as Didymoon – before ESA’s Hera comes in to map the resulting impact crater and measure the asteroid’s mass. Hera will carry two CubeSats on board, which will be able to fly much closer to the asteroid’s surface, carrying out crucial scientific studies, before touching down. Hera’s up-close observations will turn asteroid deflection into a well-understood planetary defence technique.

    The Hera mission will be presented to ESA’s Space19+ meeting this November, where Europe’s space ministers will take a final decision on flying the mission, as part of the Agency’s broader planetary defence initiatives that aim to protect European and world citizens.

    ESA’s proposed Hera spaceraft depiction.

    NASA DART Double Impact Redirection Test vehicle depiction schematic.

    See the full article here .


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    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 9:39 am on September 16, 2020 Permalink | Reply
    Tags: "ESA’s Hera planetary defense mission signs prime contractor on course for launch in 2024", , DART will carry with it an Italian-provided CubeSat called LICIACube (Light Italian CubeSat for Imaging of Asteroids)., DART will carry with it an Italian-provided CubeSat called LICIACube., LICIACube will collect images of the impact and ejecta and transmit its captured photographs back to Earth., NASA Dart Mission, , The Didymos pair- a binary asteroid   

    From NASA Spaceflight: “ESA’s Hera planetary defense mission signs prime contractor, on course for launch in 2024” 

    NASA Spaceflight

    From NASA Spaceflight

    September 15, 2020
    Chris Gebhardt

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    The European Space Agency (ESA) has signed a design, manufacturing, and testing contract with OHB of Germany for their Hera planetary defense mission, marking a major advancement toward the agency’s commitment to NASA for their joint Asteroid Impact and Deflection Assessment project.

    NASA’s portion [DART] is scheduled to launch in July 2021 and slam into the smaller of the target binary asteroid in October 2022.

    NASA DART Double Impact Redirection Test vehicle depiction schematic.

    Hera will then follow, launching in 2024 on an Ariane 6 and arriving at the binary pair in 2027 to assess how well its predecessor did in changing the orbit of its target.

    The contract signed today between ESA and OBH of Germany provides €129.4 million for a detailed design, build, and test of the Hera asteroid orbiter. The contract specifically includes the new and advanced Guidance, Navigation and Control system for the craft.

    Excluded from the OBH contract are the other deals already in place for the two CubeSats that will accompany Hera to the target binary asteroid and the long-lead technology items for the mission — contracts that are already underway.

    Unlike the first part of the joint Asteroid Impact and Deflection Assessment project from NASA, an impactor called DART, Hera will not impact either of the bodies of the target but rather perform long-term observations from a close orbit while demonstrating new technologies, particularly for autonomous deep space proximity operations.

    The target for the joint mission is the Didymos pair, a binary asteroid whose primary is 780 m in diameter and whose moonlet (small moon) is 160 m in diameter.

    The moonlet, called Dimorphos, is the target of NASA’s DART kinetic impactor.


    The Double Asteroid Redirection Test (DART): Hitting an Asteroid Head On. DART (Double Asteroid Redirection Test) is scheduled to launch no earlier than 22 July 2021 from Vandenberg Air Force Base, California, atop a SpaceX Falcon 9 rocket.

    Powered by a NEXT ion thruster, the 500 kg (1,100 lb) spacecraft will spend 15 months cruising to its destination before slamming into Dimorphos at 6.25 km/s.

    DART carries no scientific instruments, just a star tracker and camera for autonomous navigation; it is simply an impactor. It will, however, carry with it an Italian-provided CubeSat called LICIACube (Light Italian CubeSat for Imaging of Asteroids) that will deploy shortly before observing the ejecta cloud thrown up from the impact.

    LICIACube will collect images of the impact and ejecta and transmit its captured photographs back to Earth; it was offered to DART by the Italian Space Agency after ESA’s first spacecraft contribution to the mission was cancelled in 2016.

    That project, the Asteroid Impact Mission, would have worked in tandem with DART, observing the other craft’s impact while providing immediate and long-term assessments of changes to Dimorphos’ orbit and characteristics while studying the ejecta material.

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    Hera inspects DART’s impact crater. Credit ESA.

    While Hera will not be able to do that first part, most of the Asteroid Impact Mission’s objectives can be accomplished with LICIACube and Hera’s long-term in situ observations that can begin upon its arrival in 2027.

    The overall mission will test whether or not a kinetic impactor can successfully deflect potentially hazardous Earth-bound asteroids by slightly changing their orbital speed to either slow them down slightly or accelerate them slightly.

    A minor velocity change imparted to a large asteroid could — over the course of months or years — alter its orbit safely away from intersecting with Earth.

    And this is exactly what NASA and ESA seek to do on a smaller scale in the Didymos pair system. The DART spacecraft, while impacting Dimorphos at 6.25 km/s will only produce a net change in the moonlet’s velocity of 0.4 millimeters per second.

    While that is an incredibly small change in velocity, it will radically change the mutual orbit of the Didymos primary and its moon.

    As such, the interagency mission represents the first time humanity will intentionally alter another celestial body’s orbit.

    By impacting the smaller of the two bodies, which orbits the larger, NASA and ESA can safely observe how a kinetic impactor alters orbital characteristics of an asteroid.


    Hera: Our planetary defense mission.

    The Didymos pair’s overall orbit of the Sun is also extremely favorable to this type of test as its orbit does not cross that of Earth’s — meaning there’s no chance the NASA-ESA experiment could accidentally cause this pair to pose a threat to our host planet.

    When Hera then arrives in 2027, it will find a very different system than the DART spacecraft encountered while on approach for impact.

    Hera will use a suite of scientific instruments as well as two ride along CubeSats (which will attempt to land on the surface of Dimorphos) to characterize exactly how much momentum was transferred between the two objects at DART’s impact and exactly how much Dimorphos’ orbit was altered.

    This will “allow, for the first time, the validation or refinement of numerical models of the impact process at asteroid scale, rendering this deflection technique for planetary defence ready for operational use if ever needed to safeguard our home world,” notes an ESA overview of the mission.

    Hera will accomplish its scientific objectives by utilizing:

    an Asteroid Framing Camera provided by Germany (that is actually a spare unit for NASA’s Dawn spacecraft in the asteroid belt),
    a compact laser radar, or lidar, for surface mapping operations,
    a thermal infrared instrument to survey the asteroid in the mid-infrared spectral range and map temperature dispersions across Dimorphos’ surface, and
    a radio science experiment to measure the mass and mass distribution within the moon.

    These instruments will be supplemented by those carried aboard the two CubeSats, which will use radar to investigate the interior of the moonlet as well as imaging and mass spectrometers to study its mineralogical and elemental composition.

    See the full article here .

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    NASA Spaceflight , now in its eighth year of operations, is already the leading online news resource for everyone interested in space flight specific news, supplying our readership with the latest news, around the clock, with editors covering all the leading space faring nations.

    Breaking more exclusive space flight related news stories than any other site in its field, NASASpaceFlight.com is dedicated to expanding the public’s awareness and respect for the space flight industry, which in turn is reflected in the many thousands of space industry visitors to the site, ranging from NASA to Lockheed Martin, Boeing, United Space Alliance and commercial space flight arena.

    With a monthly readership of 500,000 visitors and growing, the site’s expansion has already seen articles being referenced and linked by major news networks such as MSNBC, CBS, The New York Times, Popular Science, but to name a few.

     
  • richardmitnick 7:18 am on June 24, 2020 Permalink | Reply
    Tags: "An Agency for asteroids", , ESA Hera planetary defence mission, ESA-Space Safety & Security, , Europe’s NEO Coordination Centre, NASA Dart Mission   

    From European Space Agency – United Space in Europe: “An Agency for asteroids” 

    ESA Space For Europe Banner

    From European Space Agency – United Space in Europe

    23/06/2020

    The destination of ESA’s Hera mission for planetary defence – a tiny asteroid moonlet – has finally received its official name. After years of informal nicknames and temporary designations, the smaller of the Didymos asteroid pair has been formally christened ‘Dimorphos’ by the International Astronomical Union.

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    Space Safety & Security
    As we discover more about the brilliant scale and nature of the Universe, planet Earth’s blue oceans, green forests and glistening city lights appear even more unique, and even more fragile. Many hazards have been identified originating in space, which although unlikely, continue to pose real dangers to our way of life, and in the worst cases to human health and safety. Only in the past decades have we had the opportunity to understand the potential perils of our position in our Solar System, and as technologies continue to advance we are entering a period in which we can actually act. However, as technologies advance, so too does our dependence on them, making us more vulnerable to both human-made and natural threats in space. ESA’s Space Situational Awareness (SSA) programme was launched in 2009, with the aim of ensuring that Europe can independently detect, predict and assess threats from space and their potential risk to life, property and infrastructure.

    This year’s Asteroid Day is expanding. The annual commemoration of the largest asteroid impact in recorded history on 30 June is being preceded by plentiful digital video content, including programming by ESA, highlighting our work studying, surveying and safeguarding against asteroids.

    Asteroids have influenced Earth’s development, as seen by the millions of impact craters scarring our world. They are also a promising source of future resources and – last but not least – they pose a proven threat to Earth and human civilisation.

    On 30 June 1908, the Tunguska impact felled many millions of trees across 2200 sq km of Siberian territory, only a few hours of Earth rotation away from Europe – the results would have been disastrous over a populated area.

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    Felled trees as seen by Leonid Kulik, Soviet Academy of Sciences, 15 kilometres from epicentre of aerial blast site, caused by explosion of a meteorite in 1908 (Photo N. A. Setrukov, 1928)

    ESA and Space Safety

    Under the Agency’s Space Safety Programme, which received an important boost in funding at the Space19+ Ministerial Council in November 2019, ESA is taking action as part of an international effort to mitigate the asteroid risk.

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    Asteroids in the Solar System. A visualisation of some of the asteroids in our solar system, created by NASA asteroid researcher Paul Chodas.

    ESA’s goal is to coordinate Europe’s part of a global planetary defence effort, aimed at detecting, studying and following asteroids, predicting if and when they might hit and taking mitigation action if needed.

    ESA came face-to-face with its first asteroid in September 2008, when the Rosetta comet chaser performed a flyby of the 5 km ‘diamond-shaped’ Šteins asteroid.

    ESA/Rosetta spacecraft, European Space Agency’s legendary comet explorer Rosetta

    A second close encounter took place in 2010, as Rosetta passed the mammoth 100 km Lutetia – some 250 times bigger than Rosetta’s final target, Comet 67P/Churyumov–Gerasimenko.

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    Infographic: asteroid danger explained

    These bodies both reside in the Asteroid Belt, a safe distance away. ESA, however, also performs detection and analysis of asteroids whose orbits bring them close to Earth, known as near-Earth objects (NEOs). There are an estimated 40 000 000 NEOs out there larger than 10 m – the rough threshold above which damage on the ground could happen.

    Europe’s NEO Coordination Centre

    As part of its space safety activities, ESA coordinates observatories and astronomers worldwide through its NEO Coordination Centre, located at ESA’s ESRIN facility in Italy. Here, astronomers, dynamicists and other experts assess newly reported asteroid observations, accurately compute their orbits and perform sophisticated risk analysis to predict if an NEO might cause any threat to Earth, and if so, when.

    ESA performs its own long-running NEO observations from various sites including our Optical Ground Station telescope on the volcanic slopes of Tenerife. ESA carries out follow-up tracking of potentially dangerous objects using facilities around the globe, including a collaboration with the European Southern Observatory’s Very Large Telescope.

    ESA Optical Ground Station, on the premises of the Instituto Astro- física de Canarias (IAC) at the Observatorio del Teide, Tenerife

    ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
    •KUEYEN (UT2; The Moon ),
    •MELIPAL (UT3; The Southern Cross ), and
    •YEPUN (UT4; Venus – as evening star).
    elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

    Flyeye telescopes

    Building on this experience, ESA is developing a new type of automated telescope for nightly sky surveys. This ‘Flyeye’ telescope splits its image into 16 smaller subimages to expand the field of view, similar to the technique exploited by a fly’s compound eye.

    ESA Flyeye telescope

    The first Flyeye telescope will be installed atop the 1865 m Monte Mufara in Sicily by 2022; the same island where the very first asteroid was discovered back in 1801. The next step will be a network of these Flyeye telescopes around the globe, which would completely scan the sky and automatically identify possible NEOs for follow up and later checking by human researchers.

    Hera planetary defence mission

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    Hera at Didymos. ESA’s Hera mission concept, currently under study, would be humanity’s first mission to a binary asteroid: the 780 m-diameter Didymos is accompanied by a 160 m-diameter secondary body. Hera will study the aftermath of the impact caused by the NASA spacecraft DART on the smaller body.

    NASA DART Double Impact Redirection Test vehicle depiction schematic

    So what happens if a potentially dangerous asteroid is identified? ESA is participating in an international collaboration to answer that question. Next year will see the launch of NASA’s Double Asteroid Redirection Test mission, which in 2022 will collide with the smaller of the Didymos asteroid pair to shift its orbit.

    Next, ESA’s 2024-launched Hera spacecraft will perform a close-up survey of the post-impact asteroid, gathering data to turn this grand experiment into a fully characterised planetary defence technique that could be tailored to particular targets, should an incoming body ever need deflecting for real.

    As well as hazards, asteroids represent future opportunities.

    Hera will test autonomous guidance and navigation systems in the asteroid’s low-gravity environment that should prove valuable for future asteroid mining; ESA has been studying the use of space resources from asteroids along with other planets.

    Future missions to small bodies

    The first in a new generation of miniaturised spacecraft, the suitcase-sized M-Argo CubeSat, is currently being designed with the aim of expanding scientific knowledge of asteroids to be applied to future resource exploitation missions.

    ESA’s Comet Interceptor mission in collaboration with JAXA, is planned to launch near the end of the decade and will wait near Earth while scientists search for a suitable, reachable long-period comet, potentially even an interstellar comet.

    Following target selection, the mission will set out on an intercept course, deploying two smaller probes to perform a multi-point fly-by. The mission will give us a first look, simultaneously from three viewpoints, at a ‘dynamically new’ object that contains unprocessed material surviving from the dawn of the Solar System.

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    Suitcase-sized asteroid explorer

    ESA programming schedule

    ESA’s Asteroid Day 2020 dedicated-language segments will premiere in Asteroid Day TV (followed by frequent replay until 4 July) as follows:

    Italian 24 June 17:00-18:00 CEST

    German 25 June 17:00-18:00 CEST

    French 25 June 18:30-19:30 CEST

    Dutch 26 June 11:00-12:00 CEST

    Spanish 26 June 17:00-18:00 CEST

    English 30 June 12:00-13:00 CEST and 18:00-19:00 CEST

    More information and full broadcast schedule via https://asteroidday.org/broadcast-schedule/

    All segments will be broad- and webcast to the public via AsteroidDay.org, via SES Satellite and to other broadcasters via satellite and digital CDN via RTL’s Broadcasting Center Europe (BCE).

    Segments will also be available via ESA Web TV and ESA’s YouTube channel

    See the full article here .


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    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 8:29 am on June 3, 2020 Permalink | Reply
    Tags: "Queen’s Brian May works to probe origin of asteroids", Bennu and Ryugu asteroids, , , NASA Dart Mission   

    From European Space Agency – United Space in Europe: “Queen’s Brian May works to probe origin of asteroids” 

    ESA Space For Europe Banner

    From European Space Agency – United Space in Europe

    6.2.20

    Queen guitarist and astrophysicist Brian May has teamed up with asteroid researchers to investigate striking similarities and a puzzling difference between separate bodies explored by space probes.

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    Queen guitarist and astrophysicist Brian May © brianmay.com

    The research team ran a supercomputer-based ‘fight club’ involving simulated large asteroid collisions to probe the objects’ likely origins. Their work is reported in Nature Communications.

    Both the 525-m diameter Bennu asteroid visited by NASA’s OSIRIS-REx and 1-km diameter Ryugu asteroid reached by Japan’s Hayabusa2 possess the same distinct spinning-top shape and similar material densities.

    NASA OSIRIS-REx Spacecraft

    JAXA/Hayabusa 2 Credit: JAXA/Akihiro Ikeshita

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    Asteroids Bennu and Ryugu

    However the pair contain differing amounts of water, as revealed in spectral mapping of hydrated materials. Ryugu appears weakly hydrated compared to Bennu, despite being a comparative youth in asteroid terms, estimated at a mere 100 million years old.

    Spinning-top-shaped mystery

    The study was led by Patrick Michel, CNRS Director of Research of France’s Côte d’Azur Observatory, also lead scientist of ESA’s Hera mission for planetary defence. He notes that this research also has relevance for Hera, which will explore the Didymos binary asteroid system following the orbital deflection of the smaller of the two bodies by NASA’s DART spacecraft.

    NASA DART Double Impact Redirection Test vehicle depiction schematic

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    NASA’s DART impacting asteroid

    “This spinning top shape of Bennu and Ryugu – including a pronounced equatorial bulge – is shared by many other asteroids, including the primary 780-m Didymos asteroid,” explains Patrick.

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    Didymos with its moon. Credit: ESA

    “A leading hypothesis has been that a high rate of spin leads to centrifugal force changing their shape over time, as material flows from the poles to the equator. Such a spin can be built up over time by the gradual warming of sunlight – known as the Yarkovsky–O’Keefe–Radzievskii–Paddack (YORP) effect, named after four different asteroid researchers.

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    Asteroid fragments re-accumulating

    “For Didymos, this might explain where Didymos A’s smaller moonlet came from – forming out of material that broke free of the fast-spinning equator. In the case of Bennu and Ryugu there is a problem however: close-up inspection by their respective spacecraft has revealed large craters on their equatorial ridges, suggesting these bulges formed very early in the asteroids’ history.”

    The findings posed a question, explains co-lead author Ron Ballouz of the Lunar and Planetary Laboratory at the University of Arizona: “Are these properties – asteroid shape, density, more or less high hydration levels – the consequence of the evolutions of these objects, once formed, or the immediate outcome of their formation?”

    Step back in time with supercomputer simulations

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    Bluecrab supercomputer cluster operated by the Maryland Advanced Research Computing Center, through the Johns Hopkins University and University of Maryland.

    As a way of looking back in time, the researchers ran numerical simulations of 100-km class asteroids being disrupted by collisions, releasing plentiful fragments that gradually reformed into aggregate bodies – believed to be the way that most asteroids larger than 200 m have been formed.

    The simulations were run using the Bluecrab supercomputer cluster operated by the Maryland Advanced Research Computing Center, through the Johns Hopkins University and University of Maryland.

    “The simulation runs were extremely computationally intense, and took several months to perform,” adds Patrick Michel. “The most challenging part was simulating the re-accumulation process, which included detailed coding for particle contact including rolling, sliding and shear friction. We also looked at the heating level of the post-impact fragments, determining their hydration level.

    “What we found was, while the re-accumulation process led to a wide variety of shapes, there is a tendency towards a spinning-top because the aggregating material can be captured in a central disc and eventually forms a spinning top or at least a re-accumulated spheroid. This spheroid can then be spun up by the YORP effect to form an equatorial bulge in a rapid timescale in asteroid terms, of less than a million years, explaining what we see on Bennu and Ryugu.”

    The team’s other finding is that final hydration levels can vary markedly among the aggregates formed by the disruption of their parent body. Brian May worked with Claudia Manzoni of the London Stereoscopic Company to produce stereogram 3D images of the immediate aftermath of impacts, revealing individual fragments show a broad diversity in heating levels, and therefore hydration.

    “During a collision, it is thus possible to form an aggregate like Bennu, that experienced little impact heating, and another with more heated material, such as Ryugu,” explains Brian May.

    7
    Stereogram images of simulated asteroid disruption.

    Asteroid family trees

    Patrick Michel adds: “The upshot is that Bennu and Ryugu might actually be part of the same asteroid family, originating from the same parent, despite their very different hydration levels now. We know they come from the same region of the Asteroid Belt, which makes this more likely, although we will only know for sure when we can analyse the asteroid samples due to be returned by Hayabusa2 and OSIRIS-REx.”

    Brian May’s involvement came out of his asteroid research activities, including working on the Hayabusa2 and OSIRIS-REx science teams and as a member of the Advisory Board of the Near-Earth Object Modelling and Payload for Protection (NEO-MAPP) project, funded by the H2020 program of the European Commission.


    Hera: ESA’s planetary defence mission

    See the full article here .


    five-ways-keep-your-child-safe-school-shootings
    Please help promote STEM in your local schools.

    Stem Education Coalition

    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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