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  • richardmitnick 8:52 am on September 11, 2019 Permalink | Reply
    Tags: , , ESA HERA spacecraft, ESA/NASA “AIDA” collaboration (for Asteroid Impact Deflection Assessment),   

    From European Space Agency: “A burst of asteroid activity in Europe” 

    ESA Space For Europe Banner

    From European Space Agency

    10 September 2019

    The next few days will see a rare convergence of asteroid-related activity in Europe, as planetary defence and other experts meet in three locations to coordinate humanity’s efforts to defend ourselves from hazardous space rocks.

    Such intense levels of international scientific collaboration are driven in part by the fact that an asteroid impact could cause devastating effects on Earth. But this is also a testament to the fact that we are at a point in human history where we can do something about risky asteroids.

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    Infographic: asteroid danger explained

    According to recent ESA estimates, there are 878 asteroids in the ‘risk list’. This ESA catalogue brings together all asteroids we know of that have a ‘non-zero’ chance of impacting Earth in the next 100 years – meaning that an impact, however unlikely, cannot be ruled out.

    An impact by even a small asteroid could cause serious destruction to inhabited areas. This is why ESA, together with international partners, is taking action to search for asteroids, develop technology that could deflect them in future and collaborate at the international level to support mitigation measures.

    The flurry of upcoming meetings will cover vital topics in planetary defence, including the planned, first-ever test of asteroid deflection, coordination and communication of asteroid warnings and how to ensure the most effective emergency response on the ground. With all the work being done, the planet has never been so prepared for the unlikely but very real threat of an asteroid impact.

    The ESA/NASA “AIDA” collaboration (for Asteroid Impact Deflection Assessment) will see NASA’s DART spacecraft crash into and deflect the 160-m asteroid Didymos-B (also known as Didymoon, the smaller of the Didymos dual asteroid system).

    NASA DART Double Impact Redirection Test vehicle depiction schematic

    Later, ESA’s Hera mission will survey the crash site and gather the maximum possible data on the effects of this collision.

    ESA’s proposed Hera spaceraft

    The AIDA workshop brings together asteroid researchers and spacecraft engineers from the US, Europe and around the world to discuss the latest in this first-ever test of asteroid deflection, planned for 2022.

    Astronomers from both sides of the Atlantic will also be reporting on the latest observation campaigns to gather additional data on the Didymos asteroid system, helping with the planning of both missions.

    The International Asteroid Warning Network, currently led by NASA, and the ESA-chaired Space Mission Planning Advisory Group regularly meet to discuss all things asteroid.

    Both groups have mandates from the UN to coordinate, at the international level, different aspects of any future responses to any asteroid risks.

    The latest meetings will be hosted by the European Southern Observatory in Garching, Munich.

    The organisations will discuss the recent ‘non-detection’ of asteroid 2006 QV89, the latest news from the Minor Planet Center and how asteroid warnings are communicated to the public and media.

    Representatives of civil protection agencies from six countries including Germany, Switzerland and the US, as well as from the United Nations Office for Outer Space Affairs, will join ESA’s Planetary Defence Office at the Agency’s operations centre in Darmstadt, Germany.

    This will be the third in a series of emergency response workshops with the purpose of establishing a link between ESA and national civil protection authorities, ensuring national agencies understand the asteroid threat and how ESA can support them in their work to protect life and infrastructure on the ground.

    These three meetings illustrate the breadth of activity currently taking place across the globe to mitigate the risk of an asteroid impact, to ensure early warnings of such a threat, and to prepare on Earth in the unlikely event of a strike – planetary defence is heating up!

    Find out more about ESA’s Planetary Defence activities, here.

    See the full article here .


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    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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  • richardmitnick 8:58 am on June 27, 2019 Permalink | Reply
    Tags: , , , , , , ESA HERA spacecraft, , Planetary defence   

    From European Space Agency: “Video: ESA defending Earth” 

    ESA Space For Europe Banner

    From European Space Agency

    25/06/2019
    ESA’s planetary defence mission

    Hera will show us things we’ve never seen before.

    ESA’s proposed Hera spaceraft

    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.

    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.

    NASA DART Double Impact Redirection Test vehicle depiction schematic

    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.

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    ESA APEX CubeSat

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    Juventas CubeSat

    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.

    See the full article here .


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    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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  • richardmitnick 10:47 am on March 6, 2019 Permalink | Reply
    Tags: "World’s best telescopes target Didymos asteroids for ESA’s Hera mission", , , At such a distance even observed through our planet’s largest telescopes the asteroid pair appear as no more than a single bright point, , , Currently some 145 million km from Earth the main Didymos asteroid is around 780 m across with the smaller ‘Didymoon’ about 160 m across orbiting around 1 km away from its parent, ESA HERA spacecraft, The Didymos asteroids   

    From European Space Agency: “World’s best telescopes target Didymos asteroids for ESA’s Hera mission” 

    ESA Space For Europe Banner

    From European Space Agency

    5 March 2019


    Gran Telescopio Canarias at the Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, Spain, sited on a volcanic peak 2,267 metres (7,438 ft) above sea level

    In the coming days the largest and most powerful telescopes in Europe and South America will be trained on a single spot in the sky, gathering details of twin asteroids to help guide the design of ESA’s proposed Hera mission, headed for the Didymos pair in late 2023.

    ESA Hera spaceraft

    Right now the Didymos asteroids are in opposition, meaning they are visible on the opposite side of the sky than the Sun. Currently some 145 million km from Earth, the main Didymos asteroid is around 780 m across with the smaller ‘Didymoon’ about 160 m across, orbiting around 1 km away from its parent.

    At such a distance, even observed through our planet’s largest telescopes, the asteroid pair appear as no more than a single bright point – about 200 000 times fainter than the faintest stars visible to the naked eye. But tiny variations in that brightness over time can give vital insights into the Didymos system.

    The observing campaign will commence over three nights from 8 March with the 10.4-m diameter Gran Telescopio Canarias telescope – the world’s largest single aperture optical reflector – located at the El Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, Spain, and managed by the Instituto de Astrofísica de Canarias.

    The observations will progress over the next four nights using the 4.2-m diameter William Herschel Telescope – Europe’s second largest optical telescope –at the same site.


    ING 4.2 meter William Herschel Telescope at Roque de los Muchachos Observatory on La Palma in the Canary Islands, 2,396 m (7,861 ft)

    In April the campaign will shift to the southern hemisphere, with three nights of observation during the month from the Very Large Telescope – an interlinked quartet of 8.2 m diameter telescopes – at the European Southern Observatory site on a flattened mountaintop in Paranal, Chile.

    ESO VLT 4 lasers on Yepun


    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,

    These observations will be led by astronomers Benoit Carry of the Observatoire de la Côte d’Azur, in Nice, France and Colin Snodgrass of the UK’s Open University.

    The observing campaign is being coordinated by a group of leading European astronomers, known as the Hera Remote Observations Working Group, supporting the planning of ESA’s Hera planetary defence mission.

    “Didymos is at its brightest at the moment, so we submitted a series of observing requests that were all accepted by the observatories,” explains astronomer Julia de Leon of the Instituto de Astrofísica de Canarias.

    “The asteroids are too far away to resolve any features directly, but we use advanced CCD light detectors to measure small changes in brightness over time, which we can then convert into ‘lightcurves’. These are patterns of light shifts which we can employ in turn to derive details of the Didymos system.”

    The collective brightness of the pair varies as the two objects rotate, and also as Didymoon passes in front of, then behind, Diymos. Sharpening the lightcurves through fresh observations should yield valuable new information.

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    Didymos lightcurve. The folded lightcurve of Didymos (panel a) can be decomposed into a contribution from the rotation of Didymos (panel c) and a contribution due to mutual events with Didymoon (panel b). Figure taken from Pravec et al. (2006).

    “To achieve this, we really need the largest aperture, best telescopes in the world,” comments astronomer Petr Pravec of Ondřejov Observatory in the Czech Republic. “We need enough precision to pinpoint tiny details in the shape of the lightcurve. In particular, the shape and rotation of the secondary asteroid is still unknown.”

    Pravec, together with Petr Scheirich from the same institution, is in charge of analysing the lightcurve data to interpret it and model the binary asteroids.

    As astronomer Alan Fitzsimmons, of the UK Queen’s University Belfast, notes: “We assume Didymoon is tidally locked to its parent like our own Moon, which always presents the same face to Earth, but we want to be sure as the Hera mission design gets underway.

    “This is especially important as the state of the Didymos system is set to change after 2022, when the US DART spacecraft will impact Didymoon in a historic first test of asteroid deflection techniques. Then in 2026 Hera arrives to take a close-up look.”

    NASA DART Double Impact Redirection Test vehicle depiction schematic

    Hera is being designed to gather essential knowledge to develop planetary defence techniques that is impossible to be gleaned from astronomical observations alone, or the imagery DART returns before its collision (the US spacecraft will also carry an Italian-made ‘SelfieSat’ CubeSat). Chief among these are the mass of Didymoon and the size and shape of the crater left by DART’s impact.

    A parallel group of US astronomers is supporting the DART mission, undertaking their own campaign, and the two groups coordinate observations and share data.

    “We were involved in preparations for the Asteroid Impact Mission, and decided to keep involved for Hera,” notes astronomer Simon Green of the Open University.

    “No binary asteroid system has been studied in detail by a spacecraft, so Hera’s close investigation should return a wealth of information – as well as increasing our knowledge of planetary defence.”

    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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  • richardmitnick 7:52 am on February 23, 2018 Permalink | Reply
    Tags: , , , , , , ESA HERA spacecraft, SCITECH Europa   

    From ESA via SCITECH Europa: “Crash investigation” 

    ESA Space For Europe Banner

    European Space Agency

    1

    SCITECH Europa

    21st February 2018
    Ian Carnelli
    Programme Manager
    General Studies Programme (GSP)
    European Space Agency (ESA)

    1
    ESA HERA

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    Hera will provide humanity’s first view of a binary asteroid system, proceeding to map the entire surface of ‘Didymoon’ down to a size resolution of a few meters and the tenth of the surface surrounding the DART impact to better than 10cm, through a series of daring flybys © ESA – ScienceOffice.org

    ESA’s Hera mission is designed to test deep space technology while exploring a distant asteroid and investigating a unique, man-made crater, testing a deflection method that may one day prove literally Earth-saving.

    If all goes to plan, October 2022 will mark a significant achievement in the life of our species: the first time that Homo sapiens shifts the orbit of a body in the Solar System in a measureable way. The target is an approximately 170-m diameter asteroid – about the same size as the Great Pyramid of Giza – which is in orbit around another, larger asteroid: the 780m diameter Didymos (Greek for ‘twin’) near-Earth asteroid.The method is a NASA spacecraft called the Double Asteroid Redirection Test (DART), which will autonomously fly itself into the smaller body at 6km/s, nine times faster than a bullet.

    NASA DART Double Imact Redirection Test vehicle

    The result of the collision with this refrigerator-sized DART spacecraft is expected to be an alteration in the tight 11.9-hour orbit of ‘Didymoon’ around its parent asteroid. This shift should be observable from Earth-based telescopes, because the Didymos binary pair will be on an unusually close approach to our planet at that point, coming just 11 million kilometres away at its nearest.

    Didymoon’s degree of orbital shift will give researchers essential insights into the internal structure of asteroids and the potential of deflecting them as a means of planetary defence. But monitoring this historic event from a distance will not be sufficient by itself if we are to learn all its lessons.

    By its very nature the Double Asteroid Redirection Test is a suicide mission, which has some unavoidable drawbacks. The last thing Earth will see in advance of the collision will be a close-up of Didymoon’s surface features – and then nothing. Potentially, DART might also carry a small ‘selfie-sat’ that it deploys beforehand in order to capture imagery of the moment of impact – but even so, past experience suggests nothing will be viewable directly at that point and only very limited data will be available on the surface properties of Didymoon.

    Deep impact

    On 4 July 2005, NASA’s spacecraft shot a 370kg copper impactor into comet Tempel 1.

    NASA Deep Impact spacecraft

    Shifting the orbit of this massive 7.6km × 4.9km body was never on the agenda; instead the aim was to expose the comet’s interior. However, in the impact’s aftermath millions of kilograms of dust and ice continued to outgas from the impact zone for days on end.

    Deep Impact’s follow-on flyby showed nothing; it took a new visit by a separate spacecraft, NASA’s Stardust, in 2011 to finally measure the fresh 150m diameter crater scarring the comet’s surface.

    NASA Stardust spacecraft

    Plus, the distance involved means that terrestrial observatories’ measurement of Didymoon’s altered orbit will be stuck with a 10% residual uncertainty. The only way to improve on this, and really hone our understanding of this grand-scale space experiment, and see how the Double Asteroid Redirection Test impact has affected the surface of Didymoon, is to venture much, much nearer.

    ESA’s Hera mission

    That is the task of ESA’s Hera mission, the optimised design of which benefits from multiple ESA studies of asteroid missions across the last two decades – most recently the proposed Asteroid Impact Mission (AIM), which was planned in conjunction with the Double Asteroid Redirection Test. Hera is a small-scale mission in planetary terms, a large desk-sized spacecraft weighing in at less than 800kg fully fuelled (compared, for instance, to the van-sized, three tonne Rosetta comet-chaser). But it is also a highly agile, ambitious one.

    Europe’s first deep-space CubeSat

    In addition to its primary planetary defence objectives, Hera will demonstrate the ability to operate at close proximity around a low-gravity asteroid with some on-board autonomy similar in scope to a self-driving car, going on to deploy Europe’s first deep-space CubeSat, and potentially also a micro-lander, to test out a new multi-point intersatellite link technology.

    Hera will also provide humanity’s first view of a binary asteroid system, proceeding to map the entire surface of Didymoon down to a size resolution of a few meters and the tenth of the surface surrounding the Double Asteroid Redirection Test impact to better than 10cm, through a series of daring flybys. How large a crater will Double Asteroid Redirection Test end up leaving? Will there be larger morphological effects, such as ground cracking, or stones and dust scattered widely compared to DART’s pre-impact images, implying post-collision quaking?

    Planetary defence

    Precise mapping of Didymoon’s volume will be combined with radio science experiments to assess how Didymoon’s gravity influences the spacecraft’s trajectory, to derive the asteroid’s density and constrain our models of its internal structure. Hera will also be a pioneer in the novel field of planetary defence: by pinpointing the shift in Didymoon’s orbit to a much greater precision than is achievable from Earth, the mission will give the fullest possible insight into the end result of the Double Asteroid Redirection Test collision – serving up hard data that might one day be used to safeguard Earth, demonstrating how to divert an incoming body before it becomes a threat.

    What is Hera’s Asteroid Framing Camera (AFC)?

    Hera’s baseline payload begins with an instrument called the Asteroid Framing Camera (AFC), to be used for guidance and navigation as well as scientific observation, which is an already-existing flight spare of a German contribution to NASA’s Dawn mission to the asteroid belt.

    NASA Dawn Spacescraft

    This camera has been distinguished by returning remarkable images of the largest single asteroid, Ceres, and its mysterious bright spots.

    Now, its sister camera is set to survey the smallest asteroid humankind has visited as well. The AFC is joined by a compact lidar (or ‘laser radar’) instrument to be used for measuring surface altimetry, plus one or more deployable six-unit CubeSat nanosatellites to carry a hyperspectral imager and a second instrument still to be finalised.

    At the time of writing, Hera still has another 40kg of payload capacity available, which could take the shape of a high-frequency radar for measurement of subsurface properties, a mini-impactor proposed by Japan (a twin of the version currently in flight on Japan’s Hayabusa-2 asteroid mission, see below) or a mini-lander, currently under study by Airbus and DLR, the German Aerospace Center (based on a version also in flight aboard Hayabusa-2).

    Space servicing vehicles

    ESA has a long tradition of technology-testing missions being used for ambitious science goals, exemplified since the turn of the century by the Proba series of minisatellites, variously tasked with gathering data for environmental and solar science. Hera follows the same philosophy, even though it will go one better than the Proba family by departing Earth orbit entirely.

    The single most significant technology Hera will demonstrate during its mission to the Didymos binary is intangible in nature, a software algorithm rather than physical hardware, but one seen as essential to a coming class of autonomous ‘space servicing vehicles’.

    Hera’s streamlined nature means it will perform its guidance, navigation and control (GNC) activities through an innovative data fusion strategy, combining inputs from multiple sensors to build up a detailed picture of its surroundings in space. That would mean the bringing together second-by-second of visual tracking of distinctive features on the asteroid surface with altimeter distances plus onboard inertial and star tracker measurements. Future servicing vehicles would need to perform comparable data fusion when it comes to rendezvous and docking with satellites intended to be refurbished, refuelled or potentially deorbited. Any mistake in this scenario would lead to catastrophic collision, and plentiful space debris.

    Failure is not an option

    In the case of Hera, failure will not be an option when it comes to key manoeuvres such as CubeSat (and possibly lander) deployment or close Didymoon flybys, down to a matter of metres above the surface. But what if one or more of the sensor inputs is in error or an actuator delivers the wrong correction to the spacecraft trajectory or attitude? That is where Hera’s ‘Fault Detection, Isolation and Recovery’ (FDIR) technique comes in.

    FDIR is an approach widely applied in space engineering, ranging from protecting individual electronic components to safeguarding the entire spacecraft: for example, modern space computer chips seeking to make up for memory ‘bit flips’ due to space radiation can perform calculations on a multiple, parallel basis, sometimes voting to decide the most likely truthful result. In a similar fashion, Hera’s data-fusion-based GNC FDIR is designed to identify errors in real time through ongoing sensor cross-checks, isolating them and then making up for them by triggering sensor or actuator reconfigurations or even, in case of extreme emergency, triggering an autonomous collision avoidance manoeuvre.

    The combination of GNC and FDIR using vision-based sensing was achieved by ESA for the first time in the relatively straightforward but safety-critical case of semi-autonomous docking by the Automated Transfer Vehicle cargo spacecraft to the International Space Station (ISS). Expanding the technique to more challenging rendezvouses in space and increasing its degree of autonomy has been worked on for years in the context of this mission, most recently by GMV in Spain. Success will mark a giant leap forward for mission-critical autonomy.

    What new discoveries will asteroid missions make?

    Plenty of new discoveries can be expected from Hera. Each fresh close encounter with an asteroid has led to a fresh transformation in our understanding. A decade ago Europe took its first asteroid close-up, as ESA’s Rosetta probe performed a flyby of 2867 Šteins, a Gibraltar-sized diamond-shaped asteroid in the main Asteroid Belt. Dozens of craters were seen, including a gaping hole at the south pole of Steins – a large impact crater about 2km wide and nearly 300 m deep.

    ESA Rosetta spacecraft

    A chain of several craters ran towards the north pole from this crater. The low density of Šteins suggests it is a ‘rubble pile’ asteroid, broken apart by previous impacts and held together weakly by its gravity – and probably fated to one day break apart. A second Main Belt asteroid flyby took place in 2010, as Rosetta passed the mammoth 100km 21 Lutetia. This higher-density asteroid was similarly studded with craters, confirming that collision is the main shaper of these primitive bodies.

    Europe plays a key role in a new asteroid encounter scheduled for this July, when Japan’s Hayabusa 2 reaches near-Earth asteroid 162173 Ryugu.

    JAXA/Hayabusa 2

    It will put down a micro-lander called the Mobile Asteroid Surface Scout (Mascot), developed by the German Aerospace Center [DLR] (who previously contributed the Philae lander to Rosetta) and French space agency CNES, carrying an infrared spectrometer, a magnetometer, a radiometer and camera. A follow-on version of the Mascot lander, known as Mascot+, is currently under study to be carried by Hera.

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    DLR Mobile Asteroid Surface Scout (Mascot)

    Additionally Hayabusa 2 will perform its own miniature version of an impactor experiment, called the Small Carry-on Impactor (SCI), consisting of a small 2.5kg copper projectile given added force by a high-explosive charge. SCI will strike with a velocity of 2km/s, offering a valuable bridge between the kind of simulated impact tests performed in terrestrial labs and the full-scale Double Asteroid Redirection Test collision, allowing the testing of impact scaling laws. A follow-up SCI payload is also being considered for Hera, not to attempt to change Didymoon’s trajectory any further but to produce a second crater at a different energy level than DART. This experiment will provide invaluable data to fully validate numerical impact algorithms that will be key to designing any future planetary defence missions.

    Exploration of these asteroids, and the many others surveyed so far, have highlighted their striking variety in terms of size, shape, surface characteristics and constituent materials. Similarly, asteroids rotate in various ways, from simple rotation to slow precession or rapid tumbling. It is possible that asteroid rotation is constrained by fundamental ‘spin limits’, beyond which centrifugal acceleration would lead material to escape from the surface of rubble-pile bodies. Indeed, such escapes might explain the origin of many binary asteroid systems, which make up 15% of the known total.

    New light on collisional dynamics

    The internal structure of asteroids remains a blank spot in scientific understanding. Are there large voids within their deep interior, or are they composed of loose regolith or conglomerates of monolithic rock? In particular, there is no way of knowing how an actual asteroid would respond to the specific external stimulus of an impact – short of trying it for real.

    By shedding new light on collisional dynamics, the combination of the Double Asteroid Redirection Test plus Hera will add to our understanding not just of asteroid formation and evolution but the creation and ongoing history of our entire Solar System – a story etched in impacts.

    Down at smaller scales, Hera’s surface observations will reveal the range of physical phenomena other than gravity that govern asteroid surfaces, influence their material properties and keep them bound together. What are the relative roles of electrostatic and Van der Waals forces, for instance? One proposal is that the most finely-grained asteroids might resemble ‘fairy castles’, crumbling to the touch. Such findings would hold relevance for asteroid mining as well as planetary defence, while also offering insight into the very earliest microscopic-scale processes of accretion, right back at the dawn of this and other planetary systems.

    Historic moment

    Hera is currently preparing for its Phase B1 study, along with a set of technology developments. The decision on whether the mission will progress to flight will be taken by Europe’s leaders at the end of next year. But certainly planetary defence is a global responsibility, and ESA is currently readying a new programme to be presented at the next Ministerial Council called Space Safety, that places planetary defence together with related topics such as space debris and space weather.

    DART and Hera were originally conceived as one – the origin of the two missions can be traced back to an ESA 2002 study of a double spacecraft asteroid deflection mission called Don Quijote. If approved, Hera is on track for a 2023 launch, arriving at Didymos for its ‘crime scene investigation’ a couple of years later. The experience of the Stardust crater – as well as the recently discovered crater of ESA’s Smart-1 spacecraft on the Moon – suggests DART’s impact point will be largely unchanged from the moment of collision. Or, in the event of a delay in the Double Asteroid Redirection Test mission, then the pair might reach Didymos at the same time. Either way, a historic moment is coming in the shape of the DART impact. Humankind will draw maximum benefit from it through a close-up view.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    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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