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  • richardmitnick 8:04 am on April 23, 2019 Permalink | Reply
    Tags: , , , , , , , ESA's proposed Hera spaceraft, JAXA Hayabusa 2, NASA's Deep Impact spacecraft 2004, US Double Asteroid Redirect Test or DART spacecraft   

    From European Space Agency: “Earth vs. asteroids: humans strike back” 

    ESA Space For Europe Banner

    From European Space Agency

    22 April 2019

    Incoming asteroids have been scarring our home planet for billions of years. This month humankind left our own mark on an asteroid for the first time: Japan’s Hayabusa2 spacecraft dropped a copper projectile at very high speed in an attempt to form a crater on asteroid Ryugu. A much bigger asteroid impact is planned for the coming decade, involving an international double-spacecraft mission.

    JAXA/Hayabusa 2 Credit: JAXA/Akihiro Ikeshita

    On 5 April, Hayabusa2 released an experiment called the ‘Small Carry-on Impactor’ or SCI for short, carrying a plastic explosive charge that shot a 2.5-kg copper projectile at the surface of the 900-m diameter Ryugu asteroid at a velocity of around 2 km per second. The objective is to uncover subsurface material to be brought back to Earth for detailed analysis.

    “We are expecting it to form a distinctive crater,” comments Patrick Michel, CNRS Director of Research of France’s Côte d’Azur Observatory, serving as co-investigator and interdisciplinary scientist on the Japanese mission. “But we don’t know for sure yet, because Hayabusa2 was moved around to the other side of Ryugu, for maximum safety.

    “The asteroid’s low gravity means it has an escape velocity of a few tens of centimetres per second, so most of the material ejected by the impact would have gone straight out to space. But at the same time it is possible that lower-velocity ejecta might have gone into orbit around Ryugu and might pose a danger to the Hayabusa2 spacecraft.

    “So the plan is to wait until this Thursday, 25 April, to go back and image the crater. We expect that very small fragments will meanwhile have their orbits disrupted by solar radiation pressure – the slow but persistent push of sunlight itself. In the meantime we’ve also been downloading images from a camera called DCAM3 that accompanied the SCI payload to see if it caught a glimpse of the crater and the early ejecta evolution.”

    According to simulations, the crater is predicted to have a roughly 2 m diameter, although the modelling of impacts in such a low-gravity environment is extremely challenging. It should appear darker than the surrounding surface, based on a February touch-and-go sampling operation when Hayabusa2’s thrusters dislodged surface dust to expose blacker material underneath.

    “For us this is an exciting first data point to compare with simulations,” adds Patrick, “but we have a much larger impact to look forward to in future, as part of the forthcoming double-spacecraft Asteroid Impact & Deflection Assessment (AIDA) mission.

    “In late 2022 the US Double Asteroid Redirect Test or DART spacecraft will crash into the smaller of the two Didymos asteroids.

    NASA DART Double Impact Redirection Test vehicle depiction schematic

    As with Hayabusa2’s SCI test it should form a very distinct crater and expose subsurface material in an even lower gravity environment, but its main purpose is to actually divert the orbit of the 160 m diameter ‘Didymoon’ asteroid in a measurable way.”

    The DART spacecraft will have a mass of 550 kg, and will strike Didymoon at 6 km/s. Striking an asteroid five times smaller with a spacecraft more than 200 times larger and moving three times faster should deliver sufficient impact energy to achieve the first ever asteroid deflection experiment for planetary defence.

    3
    DART mission profile. APL – Johns Hopkins University Applied Physics Laboratory

    A proposed ESA mission called Hera would then visit Didymos to survey the diverted asteroid, measure its mass and perform high-resolution mapping of the crater left by the DART impact.

    DLR Asteroid Framing Camera used on NASA Dawn and ESA HERA missions

    ESA’s proposed Hera spaceraft

    “The actual relation between projectile size, speed and crater size in low gravity environments is still poorly understood,” adds Patrick, also serving as Hera’s lead scientist. “Having both SCI and Hera data on crater sizes in two different impact speed regimes will offer crucial insights.

    “These scaling laws are also crucial on a practical basis, because they underpin how our calculations estimating the efficiency of asteroid deflection are made, taking account the properties of the asteroid material as well as the impact velocity involved.

    “This is why Hera is so important; not only will we have DART’s full-scale test of asteroid deflection in space, but also Hera’s detailed follow-up survey to discover Didymoon’s composition and structure. Hera will also record the precise shape of the DART crater, right down to centimetre scale.

    “So, building on this Hayabusa2 impact experiment, DART and Hera between them will go on to close the gap in asteroid deflection techniques, bringing us to a point where such a method might be used for real.”

    Didymoon will also be by far the smallest asteroid ever explored, so will offer insights into the cohesion of material in an environment whose gravity is more than a million times weaker than our own – an alien situation extremely challenging to simulate.

    In 2004, NASA’s Deep Impact spacecraft launched an impactor into comet Tempel 1. The body was subsequently revisited, but the artificial crater was hard to pinpoint – largely because the comet had flown close to the Sun in the meantime, and its heating would have modified the surface.

    6
    NASA’s Deep Impact hitting a comet

    NASA Deep Impact spacecraft 2004

    Hera will visit Didymoon around four years after DART’s impact, but because it is an inactive asteroid in deep space, no such modification will occur. “The crater will still be ‘fresh’ for Hera,” Patrick concludes.

    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 1:42 pm on January 2, 2019 Permalink | Reply
    Tags: , , , , Breathtaking touchdown, , JAXA Hayabusa 2,   

    From Science Magazine: “Japan’s asteroid mission faces ‘breathtaking’ touchdown” 

    AAAS
    From Science Magazine

    Jan. 2, 2019
    Dennis Normile

    1
    Hayabusa2 imaged its shadow during a rehearsal descent. JAXA

    JAXA/Hayabusa 2 Credit: JAXA/Akihiro Ikeshita

    Japan’s Hayabusa mission made history in 2010 for bringing back to Earth the first samples ever collected on an asteroid. But the 7-year, 4-billion-kilometer odyssey was marked by degraded solar panels, innumerable mechanical failures, and a fuel explosion that knocked the spacecraft into a tumble and cut communications with ground control for 2 months. When planning its encore, Hayabusa2, Japan’s scientists and engineers were determined to avoid such drama. They made components more robust, enhanced communications capabilities, and thoroughly tested new technologies.

    But the target asteroid, Ryugu, had fresh surprises in store. “By looking at the details of every asteroid ever studied, we had expected to find at least some wide flat area suitable for a landing,” says Yuichi Tsuda, Hayabusa2’s project manager at the Japan Aerospace Exploration Agency’s Institute of Space and Astronautical Science (ISAS), which is headquartered in Sagamihara. Instead, when the spacecraft reached Ryugu in June 2018—at 290 million kilometers from Earth—it found a cragged, cratered, boulder-strewn surface that makes landing a daunting challenge. The first sampling touchdown, scheduled for October, was postponed until at least the end of this month, and at a symposium here on 21 and 22 December, ISAS engineers presented an audacious new plan to make a pinpoint landing between closely spaced boulders. “It’s breathtaking,” says Bruce Damer, an origins of life researcher at the University of California, Santa Cruz.

    Yet most everything else has gone according to plan since Hayabusa2 was launched in December 2014. Its cameras and detectors have already provided clues to the asteroid’s mass, density, and mineral and elemental composition, and three rovers dropped on the asteroid have examined the surface. At the symposium, ISAS researchers presented early results, including evidence of an abundance of organic material and hints that the asteroid’s parent body once held water. Those findings “add to the evidence that asteroids rather than comets brought water and organic materials to Earth,” says project scientist Seiichiro Watanabe of Nagoya University in Japan.

    Ryugu is 1 kilometer across and 900 meters top to bottom, with a notable bulge around the equator, like a diamond. Visible light observations and computer modeling suggest it’s a porous pile of rubble that likely agglomerated dust, rocks, and boulders after another asteroid or planetesimal slammed into its parent body during the early days of the solar system. Ryugu spins around its own axis once every 7.6 hours, but simulations suggest that during the early phase of its formation, it had a rotation period of only 3.5 hours. That probably produced the bulge, by causing surface landslides or pushing material outward from the core, Watanabe says. Analyzing surface material from the equator in an Earth-based laboratory could offer support for one of those scenarios, he adds. If the sample has been exposed to space weathering for a long time, it was likely moved there by landslides; if it is relatively fresh, it probably migrated from the asteroid’s interior.

    So far, Hayabusa2 has not detected water on or near Ryugu’s surface. But its infrared spectrometer has found signs of hydroxide-bearing minerals that suggest water once existed either on the parent body or on the asteroid, says Mutsumi Komatsu, a planetary materials scientist at the Graduate University for Advanced Studies in Hayama, Japan. The asteroid’s high porosity also suggests it once harbored significant amounts of water or ice and other volatile compounds that later escaped, Watanabe says. Asteroids such as Ryugu are rich in carbon as well, and they may have been responsible for bringing both water and carbon, life’s key building block, to a rocky Earth early in its history. (Comets, by contrast, are just 3% to 5% carbon.)

    Support for that theory, known as the late heavy bombardment, comes from another asteroid sample return mission now in progress. Early last month, NASA’s OSIRISREx reached asteroid Bennu, which is shaped like a spinning top as well and, the U.S. space agency has reported, has water trapped in the soil. “We’re lucky to be able to conduct comparative studies of these two asteroid brothers,” Watanabe says.

    Geologist Stephen Mojzsis of the University of Colorado in Boulder is not convinced such asteroids will prove to be the source of Earth’s water; there are other theories, he says, including the possibility that a giant Jupiter-like gaseous planet migrated from the outer to the inner solar system, bringing water and other molecules with it around the time Earth was formed. Still, findings on Ryugu’s shape and composition “scientifically, could be very important,” he says.

    Some new details come from up-close looks at the asteroid’s surface. On 21 September, Hayabusa2 dropped a pair of rovers the size of a birthday cake, named Minerva-II1A and -II1B, on Ryugu’s northern hemisphere. Taking advantage of its low gravity to hop autonomously, they take pictures that have revealed “microscopic features of the surface,” Tsuda says. And on 5 October, Hayabusa2 released a rover developed by the German and French space agencies that analyzed soil samples in situ and returned additional pictures.

    The ultimate objective, to bring asteroid samples back to Earth, will allow lab studies that can reveal much more about the asteroid’s age and content. ISAS engineers programmed the craft to perform autonomous landings, anticipating safe touchdown zones at least 100 meters in diameter. Instead, the biggest safe area within the first landing zone turned out to be just 12 meters wide.

    That will complicate what was already a nail-biting operation. Prior to each landing, Hayabusa2 planned to drop a small sphere sheathed in a highly reflective material to be used as a target, to ensure the craft is moving in sync with the asteroid’s rotation. Gravity then pulls the craft down gently until a collection horn extending from its underside makes contact with the asteroid; after a bulletlike projectile is fired into the surface, soil and rock fragments hopefully ricochet into a catcher within the horn. For safety, the craft has to steer clear of rocks larger than 70 centimeters.

    During a rehearsal in late October, Hayabusa2 released a target marker above the 12-meter safe circle; unfortunately, it came to rest more than 10 meters outside the zone. But it is just 2.9 meters away from the edge of a second possible landing site that’s 6 meters in diameter. Engineers now plan to have the craft first hover above the target marker and then move laterally to be above the center of one of the two sites. Because the navigation camera points straight down, the target marker will be outside the camera’s field of view as Hayabusa2 descends, leaving the craft to navigate on its own.

    “We are now in the process of selecting which landing site” to aim for, says Fuyuto Terui, who is in charge of mission guidance, navigation, and control. Aiming at the smaller zone means Hayabusa2 can keep the target marker in sight until the craft is close to the surface; the bigger zone gives more leeway for error, but the craft will lose its view of the marker earlier in the descent.

    Assuming the craft survives the first landing, plans call for Hayabusa2 to blast a 2-meter-deep crater into Ryugu’s surface at another site a few months later, by hitting it with a 2-kilogram, copper projectile. This is expected to expose subsurface material for observations by the craft’s cameras and sensors; the spacecraft may collect some material from the crater as well, using the same horn device. There could be a third touchdown, elsewhere on the asteroid. If all goes well, Hayabusa2 will make it back to Earth with its treasures in 2020.

    See the full article here .


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  • richardmitnick 1:45 pm on November 3, 2018 Permalink | Reply
    Tags: , , , , , JAXA Hayabusa 2,   

    From Discover Magazine: “OSIRIS-REx Gets its First Close-up Photos of Asteroid Bennu” 

    DiscoverMag

    From Discover Magazine

    November 2, 2018
    Amber Jorgenson

    1
    OSIRIS-REx images asteroid Bennu from just 200 miles (330 kilometers) away. (Credit: NASA/Goddard/University of Arizona)

    At long last, NASA’s Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) spacecraft has delivered an up close and personal view of asteroid Bennu.

    NASA/Osiris -REx

    This composite image was created from eight shots taken by the craft’s PolyCam camera.

    OSIRIS-REx PolyCam Camera

    Transmitting data back to Earth, researchers used a super-resolution algorithm to combine the photos and give us a never-before-seen look at the asteroid’s diamond shape and rocky terrain. The mission has been spent more than two years traveling toward the carbon-rich asteroid, and is now within just 200 miles (330 kilometers) of its target.

    “The first images that capture the entire asteroid are used for an important number of calibrations that are fundamental to correctly interpret the results obtained from higher resolution images using different color filters,” said Juan Luis Rizos García, a researcher at the Instituto de Astrofísica de Canarias (IAC) and part of OSIRIS-REx’s team, in a media release.

    Once the spacecraft arrives at Bennu in December, it will switch to its color-filter MapCam, which will map the asteroid and document its physical characteristics. The camera will also look for alteration in surface minerals that could have been caused by the presence of liquid water.

    Primitive Science

    OSIRIS-REx’s obligations go far beyond taking pictures, though. The mission, which embarked on its 1.1 billion-mile (1.77 billion km) round-trip journey in September 2016, will also search for orbiting satellites, or mini-moons, study its light spectrum to determine its composition and ultimately collect samples to bring back to Earth. Scheduled for July 2020, the craft will descend to a pre-selected landing site and use its Touch-And-Go Sample Acquisition Mechanism (TAGSAM) to contact the surface.

    OSIRIS-REx TAGSAM

    In the span of just five seconds, the mission will shoot the surface with nitrogen gas and blast it into pieces small enough to take back to Earth.

    These samples will not only give researchers an untainted look at an asteroid, but they’ll also allow us to study our solar system’s formation and evolution. It’s thought that asteroids have more or less remained the same since they first formed in the early days of our solar system, and that they still house the organic molecules, volatiles and amino acids responsible for creating life on Earth. By probing asteroids, researchers could gain insight into these crucial elements and possibly track how they spread through our ancient solar system.

    And since previous observations showed that Bennu is rich in carbon, a prominent element in our solar system’s earliest asteroids, it makes for a promising, primitive target.

    But that’s not the only reason researchers decided to probe Bennu. Every six years, the asteroid comes within just 186,000 miles (300,000 km) of Earth — landing it on NASA’s list of potentially hazardous asteroids. Although the chances are slim, it’s possible that the 1,640-foot-long (500 meters) structure could impact Earth in the late 22nd century. Such an event would be far from catastrophic, but if you have the opportunity, you might as well eye up your competition.

    OSIRIS-REx’s results will come in only slightly behind those from JAXA’s Hayabusa2 mission, which arrived at asteroid Ryugu in June and will probe it until 2020.

    JAXA/Hayabusa 2 Credit: JAXA/Akihiro Ikeshita

    Combined with data from OSIRIS-REx, which will study Bennu until 2021, the time to decode asteroids and the history of our solar system could soon be upon us.

    See the full article here .

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  • richardmitnick 12:15 pm on April 2, 2018 Permalink | Reply
    Tags: , , , , JAXA Hayabusa 2, , Target is asteroid 162173 Ryugu   

    From SPACE.com: “Hayabusa2: Japan’s 2nd Asteroid Sample Mission” 

    space-dot-com logo

    SPACE.com

    March 30, 2018
    Elizabeth Howell

    JAXA/Hayabusa 2 Credit: JAXA/Akihiro Ikeshita

    Hayabusa2 is a Japanese asteroid-sampling spacecraft that launched in December 2014. It is currently on the way to asteroid 162173 Ryugu and will arrive there between June and July 2018, according to the Japanese Aerospace Exploration Agency (JAXA). The mission is a follow-up of Hayabusa, which returned samples of asteroid 25143 Itokawa to Earth in 2010 despite numerous technical difficulties.

    JAXA’s original Hayabusa spacecraft

    Mission development

    Hayabusa2 was first selected by Japan’s Space Activities Commission in 2006, and received funding in August 2010 (shortly after Hayabusa’s return). The cost is estimated at 16.4 billion yen ($150 million).

    A year after launch, Hayabusa2 briefly returned to Earth. The spacecraft made a planned flyby to get a speed boost by using the Earth’s gravitational field. Meanwhile, astronomers are doing periodic observations of Ryugu to gather information ahead of the spacecraft’s arrival. The 600-kg spacecraft is expected to remain at the asteroid for 18 months, and return to Earth in 2020 with samples on board.

    The basic configuration of Hayabusa2 is very similar to Hayabusa, except for some improved technology, according to JAXA. Here are some of the improvements on Hayabusa2.

    Ion engine: Improving the lifespan of the neutralizers (which failed on Hayabusa) by strengthening the internal magnetic field. Also, more careful checks of the ion engine will be performed to improve its propulsion generation and ignition stability.
    Sampler mechanism: Better seal performance, more compartments and an improved mechanism for picking up material from the surface. On Hayabusa, it was unclear at the time of sample collection if it had actually picked up something from the surface.
    Re-entry capsule: JAXA has added an instrument to measure acceleration, movement and interior temperatures during flight. (The Hayabusa capsule broke up during re-entry.)
    Flat antennas: Instead of Hayabusa’s parabolic antenna, Hayabusa2 will have flat antennas. This will allow it to have the same communications capacity as Hayabusa, while saving on weight (and launch fuel). “A flat antenna can perform to the same capacity as a parabolic antenna due to technological improvements … Thanks to the flat design, the weight of the antenna is reduced to one-fourth, compared to a parabolic antenna whose performance is the same.” JAXA said.

    Here are the major instruments of the mission:

    Small Carry-on Impactor (SCI): This will create an artificial crater on the surface of the asteroid. Hayabusa2 will look at the changes on the surface before and after the impact takes place. They will also sample the crater to get “fresh” materials from underground.
    Near InfraRed Spectrometer (NIRS3) and Thermal Infrared Imager (TIR): The spectrometer will look at mineral composition of the asteroid, and the properties of water there. The imager will study the temperature and thermal inertia (resistance to changing temperature) of the asteroid.
    The small rovers MINERVA-II: Three small rovers will bounce along the surface and collect data from close-up. They are successors to the MINERVA rover aboard Hayabusa, which failed to meet its target after launch.
    A small lander (MASCOT): This is a lander that will jump only once after it arrives on the surface. It will also perform close-up observations of the surface. This instrument is built by DLR (Germany’s space agency) and the CNES (France’s space agency).

    Science goals

    Japan chose a different type of asteroid to study for Hayabusa2. The goal is to collect information about a wide variety of asteroids across the solar system. Ryugu is a C-type asteroid, meaning that it is carbonaceous; with a high percentage of carbon, this is the most common type of asteroid in the solar system. (The target for Hayabusa was Itokawa, an S-type asteroid — meaning that it is made up more of stony materials and nickel iron.)

    Ryugu is an older type of body than Itokawa, and likely contains more organic or hydrated minerals, JAXA stated. Organics and water are key elements for life on Earth, although their presence on other bodies doesn’t necessarily mean life itself. “We expect to clarify the origin of life by analyzing samples acquired from a primordial celestial body such as a C-type asteroid to study organic matter and water in the solar system, and how they co-exist while affecting each other,” JAXA said.

    See the full article here .

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  • richardmitnick 5:44 am on December 6, 2016 Permalink | Reply
    Tags: , , , , JAXA Hayabusa 2   

    From Seeker: “Quest to Reveal Asteroid’s Mysteries Before Japanese Spacecraft’s Visit” 

    Seeker bloc

    SEEKER

    Dec 5, 2016
    ELIZABETH HOWELL

    hayabasu2-spacecraft
    Artist’s concept of Hayabusa-2 approaching asteroid 162173 Ryugu (1999 JU3). Image Credit: JAXA

    A Japanese spacecraft is on its way to some daring work at an asteroid. Hayabusa 2 is expected to reach Asteroid Ryugu in June or July 2018 and will drop several tiny landers on to its surface. The spacecraft itself will scoop up a sample of asteroid material for return back to Earth, just as its predecessor Hayabusa did at asteroid Itokawa a decade ago.

    It’s clear that a lot of engineering and precision is needed to achieve these maneuvers, far from home and in a zone that doesn’t easily give second chances. So as Hayabusa 2 moves towards its target, astronomers on Earth are looking at Ryugu as much as they can to learn about its properties.

    “Before you can send an interplanetary mission to a small body, it is important to know its orbit with the best possible accuracy, but you also have to know the object’s properties,” said Thomas Mueller, co-investigator for Hayabusa’s thermal infrared imager instrument, in an email to Seeker. He is also leading the efforts to do a characterization of Ryugu before Hayabusa 2’s arrival.

    The latest research is based on analyzing results from the European Herschel Space Observatory (in April 2012) and the NASA Spitzer Space Telescope (between January and May 2013). The astronomers attempted to map the rotation of the object using its light curve (the change in light as seen from Earth), which in turn led to estimating its spin and surface composition. A paper based on the research was recently published on the prepublishing site arXiv, and has been accepted in the journal Astronomy & Astrophysics.

    ESA/Herschel
    ESA/Herschel spacecraft

    NASA/Spitzer Telescope
    NASA/Spitzer Telescope

    2
    The shadow of Hayabusa, along with a target marker (circled, at left), is shown on asteroid Itokawa in November 2005. Credit: JAXA

    Mueller, who works with the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, has been interested in learning about small bodies in the solar system since his Ph.D. thesis, which he completed in 1997 — where he tried to apply infrared measurements of well-known targets to objects that were less well known, but still scientifically interesting. He’s been working to characterize Ryugu (in collaboration with the Japan Aerospace and Exploration Agency, or JAXA) since 2008.

    “Mission targets like Itokawa (Hayabusa mission in 2005) or Ryugu (Hayabusa-2 mission) always attracted my attention for many reasons,” Mueller added, providing a list: “(1) The possibility to compare my model predictions with ‘ground-truth’ at some point; (2) the relation to space projects (I worked in the European Space Agency for several years); (3) the connection between near-Earth objects and Earth (NEAs as a risk for Earth, but also as the origin of life, water and heavy element supply); (4) to find out more about the building blocks of the planets.”

    Specifically for Ryugu, Mueller says the latest research will help engineers adjust their instrument settings, do risk assessments and develop plans for what the spacecraft will do when it gets there. Some of the things they have covered include Ryugu’s estimated size, brightness (known as albedo), rotation period and spin axis, thermal properties and where grains of different sizes are distributed.

    But there are challenges with observing a small object from so far away. The new paper notes that because Ryugu is nearly spherical, it made it hard to get a light curve. So the astronomers combined radiometric and lightcurve inversion techniques to come up with an estimation of Ryugu’s physical and thermal properties.

    3
    A view of asteroid Itokawa based on data from the Hayabusa spacecraft. Credit: JAXA

    “In all our observations, we see Ryugu as a perfect point source (we cannot resolve the target from Earth distance),” Mueller added. “However, we are able to derive not only the size, shape, spin properties, but also things like the (most-likely) surface material (carbonaceous, complex organics?) or predominant grain sizes on the surface (1-10 mm).”

    He added that both Itokawa and Ryugu are “fantastic opportunities” to see how well models hold up against ground truth. The astronomers are lucky to have this opportunity, as only a fraction of small bodies are visited by spacecraft, he said.

    “Other experts in the field of small-body characterization/modelling will very likely pick up our published observations to make their own predictions,” he added. “It is very exciting for us to see who gets closest to the truth.”

    See the full article here .

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