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  • richardmitnick 8:53 am on December 18, 2014 Permalink | Reply
    Tags: , Asteroids, ESA Space Situational Awareness,   

    From ESA: “Preparing For an Asteroid Strike” 

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    European Space Agency

    18 December 2014
    No Writer Credit

    ESA and national disaster response offices recently rehearsed how to react if a threatening space rock is ever discovered to be on a collision course with Earth.

    Last month, experts from ESA’s Space Situational Awareness (SSA) programme and Europe’s national disaster response organisations met for a two-day exercise on what to do if an asteroid is ever found to be heading our way.

    In ESA’s first-ever asteroid impact exercise, they went through a countdown to an impact, practising steps to be taken if near-Earth objects, or NEOs, of various sizes were detected.

    The exercise considered the threat from an imaginary, but plausible, asteroid, initially thought to range in size from 12 m to 38 m – spanning roughly the range between the 2013 Chelyabinsk airburst and the 1908 Tunguska event – and travelling at 12.5 km/s.

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    Chelyabinsk asteroid trail

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    1908 Tunguska event

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    ESA Space Situational Awareness: detecting space hazards
    Near-Earth objects

    Teams were challenged to decide what should happen at five critical points in time, focused on 30, 26, 5 and 3 days before and 1 hour after impact.

    “There are a large number of variables to consider in predicting the effects and damage from any asteroid impact, making simulations such as these very complex,” says Detlef Koschny, head of NEO activities in the SSA office.

    “These include the size, mass, speed, composition and impact angle. Nonetheless, this shouldn’t stop Europe from developing a comprehensive set of measures that could be taken by national civil authorities, which can be general enough to accommodate a range of possible effects.

    “The first step is to study NEOs and their impact effects and understand the basic science.”

    Participants came from various departments and agencies of the ESA member states Germany and Switzerland, including Germany’s Federal Office of Civil Protection and Disaster Assista

    t
    ESA’s Optical Ground Station (OGS) is 2400 m above sea level on the volcanic island of Tenerife.

    They studied questions such as: how should Europe react, who would need to know, which information would need to be distributed, and to whom?

    “For example, within about three days before a predicted impact, we’d likely have relatively good estimates of the mass, size, composition and impact location,” says Gerhard Drolshagen of ESA’s NEO team.

    “All of these directly affect the type of impact effects, amount of energy to be generated and hence potential reactions that civil authorities could take.”

    During the 2013 Chelyabinsk event, for instance, the asteroid, with a mass of about 12 000 tonnes and a size of 19 m, hit the upper atmosphere at a shallow angle and a speed of about 18.6 km/s, exploding with the energy of 480 kilotons of TNT at an altitude of 25–30 km.

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    SSA-NEO Coordination Centre ESRIN

    While potentially a real hazard, no injuries due to falling fragments were reported. Instead, more than 1500 people were injured and 7300 buildings damaged by the intense overpressure generated by the shockwave at Earth’s surface.

    Many people were injured by shards of flying glass as they peered out of windows to see what was happening.

    “In such a case, an appropriate warning by civil authorities would include simply telling people to stay away from windows, and remain within the strongest portions of a building, such as the cellar, similar to standard practice during tornados in the USA,” says Gerhard.

    In a real strike, ESA’s role would be crucial. It will have to warn both civil protection authorities and decision-makers about the impact location and time. It would also have to share reliable scientific data, including possible impact effects, and provide trustworthy and authoritative information.

    The exercise ended on 25 November, a significant step forward at highlighting the unique factors in emergency planning for asteroid strikes, and possible courses of action. It also clarified a number of open points, including requirements from civil protection agencies and the type and time sequence of information that can be provided by ESA’s SSA.

    It is another step in the continuing effort to set up an internationally coordinated procedure for information distribution and potential mitigation actions in case of an imminent threat.

    ESA’s NEO team is also working with international partners, agencies and organisations, including the UN, to help coordinate a global response to any future impact threat (see “Getting ready for asteroids”).

    With the aim of strengthening ESA’s and Europe’s response, similar exercises will be held in the future. The next, in 2015, will include representatives from additional countries.

    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 5:17 am on December 11, 2014 Permalink | Reply
    Tags: Asteroids, , , , ,   

    From SPACE.com: “Potentially Dangerous Asteroids (Images)” 

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    SPACE.com

    April 10, 2013
    Mike Wall

    m
    This NASA graphic shows the orbits of all the known Potentially Hazardous Asteroids (PHAs), numbering over 1,400 as of early 2013. Shown here is a close-up of the orbits overlaid on the orbits of Earth and other inner planets.

    If you’ve seen films like “Armageddon,” you know the potential threat asteroids can be for Earth. To meet that threat, NASA has built a map like no other: a plot of every dangerous asteroid that could potentially endanger our planet … at least the ones we know about.

    NASA released the new map of “potentially hazardous asteroids” on Aug. 2 in a post to its online Planetary Photojournal overseen by the agency’s Jet Propulsion Laboratory in Pasadena, Calif. The map shows the orbital paths of more than 1,400 asteroids known creep too close to Earth for comfort. None of the asteroids mapped pose an impact threat to Earth within the next 100 years, agency officials said.

    “These are the asteroids considered hazardous because they are fairly large (at least 460 feet or 140 meters in size), and because they follow orbits that pass close to the Earth’s orbit (within 4.7 million miles or 7.5 million kilometers),” NASA officials explained in the image description.

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    This diagram illustrates the differences between orbits of a typical near-Earth asteroid (blue) and a potentially hazardous asteroid, or PHA (orange). PHAs have the closest orbits to Earth’s orbit, coming within 5 million miles (about 8 million kilometers), and they are large enough to survive passage through Earth’s atmosphere and cause significant damage.

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    This chart illustrates how infrared is used to more accurately determine an asteroid’s size.

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    This radar image of asteroid 2005 YU55 was obtained on Nov. 7, 2011, at 11:45 a.m. PST (2:45 p.m. EST/1945 UTC), when the space rock was at 3.6 lunar distances, which is about 860,000 miles, or 1.38 million kilometers, from Earth

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    This still from a NASA animation by Jon Giorgini of the Jet Propulsion Laboratory shows the trajectory of asteroid 2005 YU55 as it passes between Earth and the moon on Nov. 8, 2011.

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    This radar image of potentially hazardous asteroid 1999 RQ36 — the target of NASA’s Osiris-Rex sample-return mission — was obtained by NASA’s Deep Space Network antenna in Goldstone, Calif. on Sept 23, 1999.

    NASA Osiris-REx
    NASA’s Osiris-Rex spacecraft

    NASA Deep Space Network antenna
    >NASA’s Deep Space Network antenna

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    ESA’s Herschel Space Observatory captured asteroid Apophis in its field of view during the approach to Earth on January, 5-6, 2013. This image shows the asteroid in Herschel’s three PACS wavelengths: 70, 100 and 160 microns.

    ESA Herschel
    ESA Herschel schematic
    ESA/Herschel

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    The orbit of asteroid 2011 AG5 carries it beyond the orbit of Mars and as close to the sun as halfway between Earth and Venus.

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    NEOWISE survey has found that more potentially hazardous asteroids, or PHAs, are closely aligned with the plane of our solar system than previous models suggested. PHAs are the subset of near-Earth asteroids (NEAs) with the closest orbits to Earth’s orbit, coming within 5 million miles (about 8 million kilometers).

    NASA Wise Telescope
    NASA/WISE

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    NASA’s NEOWISE asteroid survey indicates that there are at least 40 percent fewer near-Earth asteroids in total that are larger than 330 feet, or 100 meters. NASA used its WISE infrared space telescope to make the find.

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    The asteroid 2012 KP24 flew past Earth on May 28, 2012. While the space rock passed within the moon’s orbit, it did not pose any danger to the planet.

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    This NASA diagram shows the orbit of newfound asteroid 2011 SM173, which flew within 180,000 miles of Earth on Sept. 30, 2011. The asteroid was discovered a day earlier on Sept. 29.

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    An object entered the atmosphere over the Urals early in the morning of Feb. 15, 2013. The fireball exploded above Chelyabinsk city, and the resulting overpressure caused damage to buildings and injuries to hundreds of people. This photo was taken by Alex Alishevskikh from about a minute after noticing the blast.

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    The Tunguska explosion flattened some 500,000 acres of Siberian forest on June 30, 1908. This image is from the Leonid Kulik expedition in 1927.

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    A 130-foot-meteor created the mile-wide Meteor Crater in Arizona. The comet proposed to have impacted life in North America was significantly larger, but no crater indicating its collision has been found.

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    Astronaut Clayton C. Anderson tweeted this picture from space, a view of Aorounga Impact Crater, southeast of of Emi Koussi volcano in Chad.

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    Landsat image (color composite) of the newfound Kebira Crater in the Western Desert of Egypt at the border with Libya. The outer rim of the crater is about 19 miles (31 km) in diameter. Image courtesy of Boston University Center for Remote Sensing

    See the full article here.

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  • richardmitnick 4:06 pm on December 4, 2014 Permalink | Reply
    Tags: Asteroids, , , , , ESA NEO, INAF   

    From ESA: “European Astronomers Spot Faint Asteroid” 

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    European Space Agency

    4 December 2014
    No Writer Credit

    European experts have spotted one of the faintest asteroids ever found – a chunk of space rock thought to be about 100 m in diameter beyond the orbit of Mars.

    as
    Asteroid

    Astronomers at the Large Binocular Telescope in Arizona, USA, spotted 2014 KC46 on the nights of 28 and 30 October. The difficult observations, close to the limits of the telescope, were carried out through a new collaboration between the Italian telescope team and ESA’s Near-Earth Object (NEO) Coordination Centre near Rome.

    The observations marked the ‘recovery’ of the asteroid – it had been seen before but then lost. This was one of the faintest recoveries of a NEO ever achieved.

    The telescope, operated by a group of institutes including the Italian National Institute for Astrophysics, spotted the object – which is about as wide as a football pitch – just beyond the orbit of Mars.

    Asteroid 2014 KC46 was rediscovered on 28 and 30 October 2014 by a new collaboration between the Italian Large Binocular Telescope team and ESA’s Near-Earth Object Coordination Centre.

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    Asteroid orbit

    The measurement of its position was sufficiently accurate to refine its orbital path and eliminate any possibility that it might hit Earth in the near future.

    “This success highlights the importance of quick response and cooperation across the asteroid community in verifying NEO orbits,” says Detlef Koschny, Head of the NEO Segment in ESA’s Space Situational Awareness programme office.

    “It also proved the effectiveness of the telescope in detecting faint objects that have large positional uncertainties.”

    The measurements have been accepted by the International Astronomical Union’s Minor Planet Center, the organisation responsible for collecting data for small bodies of the Solar System.

    The observation of this asteroid was made possible by the unique performance of the telescope, which features a large field of view combined with the ability to spot very faint objects thanks to the twin 8.4 m-diameter mirrors.

    Large Binocular Telescope
    Large Binocular Telescope

    The telescope sits at an altitude of 3200 m on Mt Graham in Arizona and has a light-gathering power equivalent to a single 11.8 m-diameter instrument.

    It is a collaboration between the Instituto Nazionale di Astrofisica, the University of Arizona, Arizona State University, Northern Arizona University, LBT Beteiligungsgesellschaft in Germany, Ohio State University, the Research Corporation in Tucson and the University of Notre Dame.

    ESA’s NEO Segment coordinates and combines information from different sources, analyses them to predict possible Earth impacts, assesses the danger and analyses possible mitigation measures, including the deflection of a threatening asteroid.

    The NEO Coordination Centre at ESA’s establishment in Frascati, near Rome, provides data and services on NEO hazards and coordinates follow-up astronomical observations.

    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 1:38 pm on November 27, 2014 Permalink | Reply
    Tags: Asteroids, , , , , , SEN   

    From SEN: “Japan’s Hayabusa 2 mission to an asteroid is set to launch” 

    SEN
    SEN

    27 November 2014
    Paul Sutherland

    As the world celebrates the success of Europe’s Rosetta, Japanese space scientists are preparing to launch the latest mission to explore one of the minor bodies of the Solar System.

    Hayabasu spacecraft
    Hayabusa 2

    Their Hayabusa 2 spacecraft is due to blast off at 1:24:48 p.m. Japanese time (04:24:48 UTC) on Sunday 30 November from the Tanegashima Space Center.

    Its mission will be to rendezvous with an asteroid, land a small probe on its surface, and then return samples to Earth. It follows an earlier Japanese Hayabusa mission to an asteroid named Itokawa.

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    Itokawa

    Asteroids generally differ from comets, such as 67P/Churyumov-Gerasimenko. which Rosetta is circling, because they don’t fizz with gas and dust. They seem to be chunks of material from the formation of the Solar System which never collected together to form planets.

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    67P/Churyumov-Gerasimenko

    ESA Rosetta spacecraft
    ESA/Rosetta

    Hayabusa 2’s target is a 1km-wide asteroid labelled 1999 JU3, after the year when it was discovered. It is a C-type asteroid, thought to contain more organic material than other asteroids, and so might again help scientists understand how the Solar System evolved.

    The Japanese space agency JAXA intend for Hayabusa 2 to catch up with asteroid 1999 JU3 in 2018. It will land a small cube-shaped probe called MASCOT (Mobile Asteroid Surface Scout) developed by the German Space Agency (DLR) together with French space partners the Centre National d’Etudes Spatiales (CNES).

    The lander is able to move its centre of gravity so that it can tip itself over in order to move across the asteroid’s surface.

    Hayabusa 2 will also carry an impactor to blast a 2-metre-wide crater in the asteroid’s surface, which will allow the spacecraft to collect fragments and bring them home for study in the laboratory.

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    Germany’s MASCOT lander is fitted to the Hayabusa 2 spacecraft. Image credit: DLR

    The first Hayabusa kept space enthusiasts and scientists on the edge of their seats with its performance. Launched in May 2003, it reached the 500-metre long Itokawa in September 2005, then twice brushed its surface, allowing some surface grains to lodge in its collector. But a bid to blast out samples from the asteroid and to land a mini-probe called Minerva both failed.

    Then fuel and power failures led scientists to fear that they had lost Hayabusa. But amazingly, they managed to regain control over the following months, and against all the odds, the probe was able to fire its capsule of precious asteroid dirt to a safe landing in the Australian Outback in June 2010.

    Hayabusa 2 is the size of a small van, measuring 1.0 metres x 1.6 metres x 1.2 metres, and has two solar panels to provide power. In space it will be driven by an ion engine using xenon propellant

    The asteroid selected by JAXA is a “perfect specimen” according to Professor Humberto Campins, an international expert on asteroids and comets, at the University of Central Florida. He has said: “Based on our analysis, it should be rich in primitive materials, specifically organic molecules and hydrated minerals from the early days of our Solar System. If successful it could give us clues about the birth of water and life in our world.”

    Scientists believe that learning more about objects such as 1999 JU3 will also help develop methods to deal with any cosmic debris, such as Near Earth Asteroids, that might be found on course to impact the Earth.

    A number of other spacecraft have visited asteroids, including Rosetta which flew past 2867 Steins in 2008 and 21 Lutetia in 2010, en route to Comet 67P/Churyumov-Gerasimenko, and NASA’s Dawn mission which is currently heading for Ceres after orbiting Vesta for a year.

    A video shows how the MASCOT lander will hit the asteroid and explore its surface. Credit: DLR

    See the full article here.

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    The vision of Sen—space exploration network—is to create a global space content network. Sen provides space news and information on the science, economics and government of space and in so doing aims to:
    —promote interest in space;
    —raise awareness of the reality of humankind and Earth in the Universe, providing a different perspective to life on this planet;
    —educate and encourage consideration of the physics, economics and government of space;
    —create a community in which people can learn, debate and share information about space;
    —further the exploration of space;
    —film the universe forever building an electronic version of the universe, a never ending work of art, creating Sen Universe – a computerised to scale 3D universe, starting with the Solar System. Sen Universe will replace computer imagery with real film and imagery as our exploration of the universe continues, forever building an electronic version of the universe, a never ending work of art and science.
    —Ultimately, in achieving the above, Sen aims to be a business without boundary in space and time.

    Space is everything, it affects everything – it defines our environment, the government of mankind, relations, the future. By promoting interest and awareness of space a different perspective of our conduct and government of life on the planet can be obtained in the hope of creating a united planet.

    Sen will aim to be an enterprise that represents the best human effort at creating an enterprise without boundary in space and time.

     
  • richardmitnick 10:33 am on November 19, 2014 Permalink | Reply
    Tags: Asteroids, , , , , ,   

    From SPACE.com: “Asteroid Found with Rings! First-of-Its-Kind Discovery Stuns Astronomers (Video, Images)” 

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    SPACE.com

    March 26, 2014
    Nola Taylor Redd

    Scientists have made a stunning discovery in the outer realm of the solar system — an asteroid with its own set of rings that orbits the sun between Saturn and Uranus. The space rock is the first non-planetary object ever found to have its own ring system, researchers say.

    The pair of space rock rings encircle the asteroid Chariklo. They were most likely formed after a collision scattered debris around the asteroid, according to a new study unveiled today (March 27). The asteroid rings also suggests the presence of a still-undiscovered moon around Chariklo that’s keeping them stable, researchers said.

    “We weren’t looking for a ring and didn’t think small bodies like Chariklo had them at all, so the discovery — and the amazing amount of detail we saw in the system — came as a complete surprise!” study leader Felipe Braga-Ribas, of the National Observatory in Brazil said in a statement today.

    Astronomers used seven telescopes, but just one revealed the pair of rings orbiting the rocky Chariklo. The asteroid’s 155-mile diameter (250 kilometers) is dwarfed by the giant gas planets, the only other bodies known to have rings.

    “This discovery shows that size is not important in order to have — or not have — rings,” Felipe Braga-Ribas, of the National Observatory in Brazil, told Space.com by email.

    An asteroid among giants

    On June 3, 2013, Braga-Ribas led a team of astronomers in observing Chariklo as it passed in front of a distant star — a process known as an occultation. As the asteroid traveled, it blocked light from the star, enabling scientists to learn more about it.

    The astronomers were surprised to discover that a few seconds before and after the main occultation, the light dimmed slightly, indicating that something circled the rocky asteroid. By comparing the data gathered from seven different telescopes, the team was able to identify the shape, size and orientation of the rings.

    The system consists of a dense, 4-mile-wide (7 km) ring near the planet, and a smaller 2-mile-wide (3 km) ring farther out.

    From the surface of the asteroid, “they would be two spectacular sharp and really bright rings, crossing all the sky,” Braga-Ribas said. “They would be noticeably close, as they are at about 1/1,000 of the moon’s distance from us,” he added.

    He went on to say that the larger, inner ring would block the view of the outer ring from the ground. The rings are similar to those around Saturn, in that both are very dense, bright and possibly formed by rock and water ice. But their scales are quite different.

    “The whole Chariklo system would fit about 12 times in the Cassini Division,” Braga-Ribas said, referring to the largest gap in Saturn’s rings.

    Particles orbiting Chariklo also travel more slowly — only tens of meters per second, compared with tens of kilometers per second in the rings of Saturn.

    While Saturn is the most well-known ringed body in the solar system, Jupiter, Neptune and Uranus also have their own, fainter rings. These gas giants significantly dwarf the smaller asteroid.

    Astronomers utilized seven telescopes, most of which were located in South America. Of them, only the European Southern Observatory’s La Silla telescope in Chile was able to capture the small gap between the rings.

    ESO LaSilla Long View
    ESO/LaSilla

    “This was possible due to the use of the ‘Lucky Imager,’ a fast and sensible camera that obtained a sequence of images like a video at a rate of 10 images per second,” Braga-Ribas said. “As the stellar occultation by both rings lasted for 0.6 seconds in total, it was able to ‘see’ the rings in detail.”

    The other telescopes had exposure times greater than 0.7 seconds, so they were only able to observe a single gap in the light.

    What’s so special about this asteroid to make it have rings?
    “Chariklo seems to be nothing special, otherwise,” Joseph Burns, of Cornell University, told Space.com by email. Burns was not a member of Braga-Ribas’ team, but he studies planetary rings and the small bodies of the solar system. He authored a perspective article that appeared alongside the new findings.

    Chariklo may not be the only nonplanetary body to have rings, Braga-Ribas said. “Rings may be a much more common property than we thought,” he said.

    The research and Burns’ accompanying article were published online today (March 26) in the journal Nature.

    Chariklo’s ‘toy ring’

    Chariklo is the largest of the centaurs, several bodies in the outer solar system whose orbits cross — and are changed by — the outer planets. The centaurs share characteristics with both asteroids and comets, and are thought to come from the Kuiper Belt region beyond Pluto. Rocky Chariklo appears to be more asteroid than comet in composition, according to the paper.

    kb
    Kuiper Belt

    This placement may help to explain the presence of Chariklo’s rings and their absence in the asteroid belt that lies between Mars and Jupiter. The rocky inner planets and the asteroid belt lie closer to the sun, and experience stronger forces from the solar wind, which can more efficiently blow small particles away from objects they might otherwise orbit, Braga-Ribas said.

    Collisions in the fast-moving asteroid belt are also violent processes due to their faster orbital speeds. Crashes between the nearby rocky bodies may wind up hurling any potential ring material away too quickly. The collision that likely created Chariklo’s rings would have had to have been a slow-moving impact. The asteroid’s small size means it has very little gravity, allowing fast-moving objects to easily escape from its orbit; the asteroid would only have been able to hold on to slower-traveling objects.

    The presence of a ring system answers questions about why the asteroid has brightened since observations in 2008. Originally viewed edge-on, the rings have become visible over the last five years as their inclination changed.

    Twice in its 29-year orbit, Saturn’s rings act the same way, appearing as a thin line to observers on Earth, Burns said. “This behavior confounded Galileo, as viewed through his crude telescope, on his discovery of Saturn’s rings,” Burns said. “It took many more observers and nearly 50 years before the rings’ nature was understood by Christiaan Huygens.”

    The age of the rings remains another mystery. Over the course of a few million years, the small pieces of a ring system should spread out. Because they are still contained as a ring, the authors concluded that either the system is very young, or the asteroid hosts a small moon that shepherds and confines the particles in their orbit. The moon would be about as massive as both rings combined, and would easily escape detection given Chariklo’s great distance.

    “Shepherds are the preferred — and basically only — explanation,” Burns said. “But Saturn’s and Uranus’ rings have many gaps where we should see shepherds and we don’t. Something is missing in our understanding. Maybe studying Chariklo’s toy rings will bring us ideas.”

    If a missing moon circles the asteroid, keeping the rings in line, then the system could have lasted since the dawn of the solar system, Braga-Ribas said, adding that the disturbance of the gas giant that moved Chariklo to its present-day orbit would require a very close pass to disturb the ring system, indicating that they could have survived the migration.

    Studying the stability of Chariklo’s rings can tell astronomers about the environment required to form and maintain them — a process that can be used to understand the dynamics of the early stages of the solar system.

    On a wider scale, the tiny ringed asteroid can also help scientists to understand more about how galaxies form.

    “The shepherd mechanism seems to be universal from the giant planets to the small minor planet,” Braga-Ribas said. “This mechanism may be acting in other kinds of debris discs, such as proto-planetary nebulae and galaxies.”

    See the full article, with other material, here.

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  • richardmitnick 5:21 pm on November 14, 2014 Permalink | Reply
    Tags: Asteroids, , , , ,   

    From JPL: “New Map Shows Frequency of Small Asteroid Impacts, Provides Clues on Larger Asteroid Population” 

    JPL

    November 14, 2014
    Media Contact
    DC Agle
    Jet Propulsion Laboratory, Pasadena, Calif.
    818-393-9011
    agle@jpl.nasa.gov

    Dwayne Brown
    NASA Headquarters, Washington
    202-358-1726
    dwayne.c.brown@nasa.gov

    bolide
    This diagram maps the data gathered from 1994-2013 on small asteroids impacting Earth’s atmosphere to create very bright meteors, technically called “bolides” and commonly referred to as “fireballs”. Sizes of red dots (daytime impacts) and blue dots (nighttime impacts) are proportional to the optical radiated energy of impacts measured in billions of Joules (GJ) of energy, and show the location of impacts from objects about 1 meter (3 feet) to almost 20 meters (60 feet) in size. Image Credit: Planetary Science

    A map released today by NASA’s Near Earth Object (NEO) Program reveals that small asteroids frequently enter and disintegrate in the Earth’s atmosphere with random distribution around the globe. Released to the scientific community, the map visualizes data gathered by U.S. government sensors from 1994 to 2013. The data indicate that Earth’s atmosphere was impacted by small asteroids, resulting in a bolide (or fireball), on 556 separate occasions in a 20-year period. Almost all asteroids of this size disintegrate in the atmosphere and are usually harmless. The notable exception was the Chelyabinsk event which was the largest asteroid to hit Earth in this period. The new data could help scientists better refine estimates of the distribution of the sizes of NEOs including larger ones that could pose a danger to Earth.

    Finding and characterizing hazardous asteroids to protect our home planet is a high priority for NASA. It is one of the reasons NASA has increased by a factor of 10 investments in asteroid detection, characterization and mitigation activities over the last five years. In addition, NASA has aggressively developed strategies and plans with its partners in the U.S. and abroad to detect, track and characterize NEOs. These activities also will help identify NEOs that might pose a risk of Earth impact, and further help inform developing options for planetary defense.

    The public can help participate in the hunt for potentially hazardous Near Earth Objects through the Asteroid Grand Challenge, which aims to create a plan to find all asteroid threats to human populations and know what to do about them. NASA is also pursuing an Asteroid Redirect Mission (ARM) which will identify, redirect and send astronauts to explore an asteroid. Among its many exploration goals, the mission could demonstrate basic planetary defense techniques for asteroid deflection.

    For more information about the map and data, go to:

    http://neo.jpl.nasa.gov

    For details about ARM, and the Asteroid Grand Challenge, visit:

    http://www.nasa.gov/asteroidinitiative

    See the full article here.

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    NASA JPL Campus

    Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center located in the San Gabriel Valley area of Los Angeles County, California, United States. Although the facility has a Pasadena postal address, it is actually headquartered in the city of La Cañada Flintridge [1], on the northwest border of Pasadena. JPL is managed by the nearby California Institute of Technology (Caltech) for the National Aeronautics and Space Administration. The Laboratory’s primary function is the construction and operation of robotic planetary spacecraft, though it also conducts Earth-orbit and astronomy missions. It is also responsible for operating NASA’s Deep Space Network.

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  • richardmitnick 10:43 am on October 24, 2014 Permalink | Reply
    Tags: Asteroids, , , , , ,   

    From astrobio.net: “The Abundance of Water in Asteroid Fragments” 

    Astrobiology Magazine

    Astrobiology Magazine

    Oct 24, 2014
    Aaron L. Gronstal

    A new study could provide insights about the abundance of water in fragments from a famous asteroid.

    two
    These colorful images are of thin slices of meteorites viewed through a polarizing microscope. Part of the group classified as HED meteorites for their mineral content (Howardite, Eucrite, Diogenite), they likely fell to Earth from 4 Vesta. Credit: NASA / JPL-Caltech / Hap McSween (Univ. Tennessee), A. Beck and T. McCoy (Smithsonian Inst.)

    The study focused on a mineral called apatite, which can act as a record of the volatiles in materials, including things like magma and lunar rocks. Volatiles are chemical elements with low boiling points (like water), and are usually associated with a celestial bodies’ crust or atmosphere.

    By looking at the apatite in meteorites, the team was able to determine the history of water in these rocks from space.

    The meteorites they chose to study are known as the Howardite-Eucrite-Diogenite (HED) meteorites. These meteorites are a subset of the achondrite meteorites, which are stony meteorites that do not have any chondrites (round grains that were formed from molten droplets of material floating around in space before being incorporated into an asteroid).

    vesta
    Vesta closeup. Credit: NASA

    Studying the composition of meteorites can provide important clues about how asteroids and other rocky bodies form and evolve. Volatile elements influence processes important to planet formation, such as melting and eruption processes.

    HED meteorites are especially interesting because scientists think they originated from the crust of the asteroid Vesta – a large body in the main asteroid belt that was recently visited by NASA’s Dawn spacecraft. Behind Ceres, Vesta is the second largest object in the asteroid belt and is sometimes referred to as a protoplanet.

    Vesta is a relic of the ancient Solar System and can help astrobiologists understand our system’s formation and evolution. This information provides clues about conditions in the Solar System that led to the formation of a habitable planet – the Earth.

    Interestingly, the team’s results from the HED meteorites are similar to studies on the Earth and Moon, and could support theories that water in all three objects (Vesta, the Earth, and the Moon) came from the same source.

    See the full article here.

    NASA

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  • richardmitnick 8:01 am on October 24, 2014 Permalink | Reply
    Tags: Asteroids, , , , ,   

    From SETI: “New Insights on the Origin of the triple asteroid system (87) Sylvia” 


    SETI Institute

    Oct 24, 2014
    Franck Marchis, Senior Research Scientist

    Combining observations from the world’s largest telescopes with those from smaller instruments used by amateur astronomers, a team of scientists has discovered that the large main-belt asteroid (87) Sylvia has a complex interior. This has been deduced by using the motions of the two moons orbiting the main asteroid as probes of the object’s density distribution. The complex structure is probably linked to the way the multiple system was formed.

    two
    Description Discovery of the two moons Romulus and Remus of the asteroid (87) Sylvia
    Date 24 January 2007
    Adaptive Optics observations of (87) Sylvia, showing its two satellites, Remus and Romulus

    The findings were announced last year at the 45th annual Division of Planetary Sciences meeting in Denver, Colorado and were published last month in the journal Icarus.

    The asteroid (87) Sylvia is the first known to have two moons. One moon was discovered in 2001, and the second was found in 2005 by a team led by Franck Marchis, senior research scientist at the Carl Sagan Center of the SETI Institute. Since then, the team has continued to make new observations of the system using 8 to 10 m-class telescopes, including those at the Keck Observatory, the European Southern Observatory, and Gemini North.

    Keck Observatory
    Keck Observatory Interior
    Keck

    ESO VLT Interferometer
    ESO VLT Interior
    ESO VLT

    Gemini North telescope
    Gemini North Interior
    Gemini North

    syl
    (credit: Danielle Futselaar/SETI Institute).
    An artist’s rendition of the triple system showing the large 270-km asteroid Sylvia surrounded by its two moons – Romulus and Remus – gives a pictorial representation of this intriguing triple system.

    The differentiated interior of the asteroid is shown in a cutaway diagram. The primary asteroid may have a dense, regularly-shaped core, surrounding by fluffy or fractured material. The outer moon, named Romulus, is known to be strongly elongated, possibly having two lobes, as suggested by a recently observed occultation recorded by amateur astronomers.

    “Combined observations from small and large telescopes provide a unique opportunity to understand the nature of this complex and enigmatic triple asteroid system,” Marchis said. “Thanks to the presence of these moons, we can constrain the density and interior structure of an asteroid, without the need for a spacecraft’s visit. Knowledge of the internal structure of asteroids is key to understanding how the planets of our solar system formed.”

    The article Physical and dynamical properties of the main belt triple Asteroid (87) Sylvia, published last month in Icarus, is co-authored by J. Berthier, F. Vachier, B. Carry from IMCCE-Obs de Paris, J. Durech from Charles University, Prague, and F. Marchis from the SETI Institute and Obs. de Paris.

    Reference
    Berthier, J., F. Vachier, F. Marchis, J. Ďurech, and B. Carry. 2014. Physical and Dynamical Properties of the Main Belt Triple Asteroid (87) Sylvia. Icarus 239 (September): 118–30. doi:10.1016/j.icarus.2014.05.046.

    Abstract
    We present the analysis of high angular resolution observations of the triple Asteroid (87) Sylvia collected with three 8-10 m class telescopes (Keck, VLT, Gemini North) and the Hubble Space Telescope. The moons’ mutual orbits were derived individually using a purely Keplerian model. We computed the position of Romulus, the outer moon of the system, at the epoch of a recent stellar occultation which was successfully observed at less than 15 km from our predicted position, within the uncertainty of our model. The occultation data revealed that the Moon, with a surface-area equivalent diameter Ds=23.1±0.7km, is strongly elongated (axes ratio of 2.7±0.32.7±0.3), significantly more than single asteroids of similar size in the main-belt. We concluded that its shape is probably affected by the tides from the primary. A new shape model of the primary was calculated combining adaptive-optics observations with this occultation and 40 archived light-curves recorded since 1978. The difference between the J2=0.024-0.009+0.016 derived from the 3-D shape model assuming an homogeneous distribution of mass for the volume equivalent diameter Dv=273±10km primary and the null J2 implied by the Keplerian orbits suggests a non-homogeneous mass distribution in the asteroid’s interior.

    See the full article here.

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  • richardmitnick 10:06 am on September 16, 2014 Permalink | Reply
    Tags: Asteroids, , , , ,   

    From SPACE.com: “US Military’s Meteor Explosion Data Can Help Scientists Protect Earth” 

    space-dot-com logo

    SPACE.com

    September 15, 2014
    Leonard David

    The U.S. Air Force and NASA have ironed out problems that prevented scientists from obtaining a steady stream of military tracking data on meteor explosions within Earth’s atmosphere.

    Ever since the meteor explosion over Chelyabinsk, Russia, in February 2013, scientists have been hungry for data that can help them assess the threat of fireballs, meteors and near-Earth objects (NEOs).

    Meteor detonations within Earth’s atmosphere can be seen by U.S. military sensors on secretive spacecraft. Using this government data, in early 2013, NASA’s Jet Propulsion Laboratory (JPL) launched a new website to share the details of meteor explosion events.

    But earlier this year, the site became stagnant, with no new updates. Due to budget cuts and personnel reductions, NASA’s military partner was no longer able to carry out the work.

    Repairing the meteor explosions pipeline

    However, documents are now in place to ensure that the site is updated with a constant stream of data on meteor explosions, which are also known as bolides. In January 2013, the Air Force Space Command’s Air, Space and Cyberspace Operations directorate formalized its work with NASA’s Science Mission directorate with a memorandum of agreement (MOA).

    bolide
    Artist’s view of 2013 fireball explosion over Chelyabinsk, Russia — termed a “superbolide” event. Credit: Don Davis

    “The MOA was amended effective June 24, 2014, in order to ensure that the flow of bolide data to the scientific community is uninterrupted,” a representative for the U.S. Air Force Space Command’s Space and Missile Systems Center (SMC), which oversees military space systems, told Space.com. “With added language to the formal MOA, SMC will provide bolide data on a consistent basis and alleviate any concerns of data flow getting cut off.”

    Furthermore, there is a separate SMC team at Schriever Air Force Base in Colorado that’s responsible for the processing and dissemination of the data, the SMC representative said.

    Trove of data

    bos
    Data gleaned from hush-hush satellite sensors can be folded into other data sets to better model just how much the Earth is on the receiving end of incoming natural objects. Picture shows Sandia National Laboratories researcher Mark Boslough reviewing a supercomputer simulation of an asteroid fireball exploding in Earth’s atmosphere. Credit: Randy Montoya/Sandia

    One big reason why the military data on bolides is so important is that there is increasing evidence that Earth is on the receiving end of a sizable amount of natural asteroid/comet material, otherwise known as “spacefall.”

    By reviewing military-sensor data collected over the years, scientists hope to better understand spacefall rates. However, all of the data isn’t available just yet.

    “The plan is to release all appropriate data, although it will take some time for processing to occur,” the SMC representative told Space.com. “The Air Force has maintained a database of all detected events. The archived raw data requires very intricate and specific processing through a software program so that it can be useful to an external organization.”

    The data will give scientists a better idea of the population of very small asteroids that regularly encounter the Earth, and help researchers estimate how many larger objects may exist, said Lindley Johnson, NEO program executive within the Planetary Science Division of NASA’s Science Mission Directorate in Washington, D.C.

    Peter Brown, director of the Center for Planetary Science and Exploration at the University of Western Ontario in Canada, called the partnership a “major step forward.”

    “Speaking from the science community perspective, I would say this partnership and agreement between Air Force Space Command and NASA is a major step forward in terms of being able to study and analyze small impactors,” Brown told Space.com.

    For example, the data from the JPL fireball website helps correlate U.S. government sensor observations of fireballs with infrasound detections by the International Monitoring System (IMS), a network overseen by the Comprehensive Nuclear-Test-Ban Treaty Organization.

    Independent check

    Researchers can calibrate the current global detection efficiency of the IMS, Brown said. This U.S. government sensor-infrasound comparison also provides an independent check on the fireball energies and flags unusual events, he said.

    “The timely release of this information on the JPL website now also permits rapid follow-up of interesting bolides to facilitate time-sensitive studies, such as meteorite or airborne dust recovery, for the first time,” Brown said.

    In addition, the data contain a “potential goldmine of information,” particularly regarding meteorite-producing fireballs and their pre-atmospheric orbits, as well as information that helps address the general question of meteorite-asteroid linkages, he said.

    Regular space rock reports

    But in order for the data to be useful, it must be distributed regularly, scientists say.

    “The [Air Force] responses sound positive,” said Clark Chapman, asteroid expert with the Southwest Research Institute in Boulder, Colorado.”But the proof of any change in practices will come with actual, regular distribution of such information to interested scientists, hopefully very shortly after a detected event,” he told Space.com.

    Chapman said he and other specialists look forward to receiving timely and regular reports of bolide events via the Air Force/NASA relationship.

    To view the “Fireball and Bolide Reports” website, overseen by NASA’s Near-Earth Object Program, visit http://neo.jpl.nasa.gov/fireballs/.

    See the full article here.

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  • richardmitnick 2:35 pm on September 4, 2014 Permalink | Reply
    Tags: Asteroids, , , ,   

    From SPACE.com: “Newfound Asteroid Will Give Earth Super-Close Shave on Sunday” 

    space-dot-com logo

    SPACE.com

    September 04, 2014
    Miriam Kramer

    Earth is about to have a close encounter with a house-sized asteroid on Sunday (Sept. 7), when a space rock discovered just days ago will zoom by our planet at a range closer than some satellites. But have no fear, NASA says the asteroid won’t hit Earth.

    The asteroid 2014 RC will safely buzz Earth at 2:18 p.m. EDT (1818 GMT) on Sunday. At that time, the asteroid will pass over New Zealand and fly just inside the orbits of the geosynchronous communications and weather satellites orbiting Earth about 22,000 miles (36,000 kilometers) above the planet’s surface, according to a NASA statement. That’s about 10 times closer to the Earth than the moon.

    “Asteroid 2014 RC was initially discovered on the night of August 31 by the Catalina Sky Survey near Tucson, Arizona, and independently detected the next night by the Pan-STARRS 1 telescope, located on the summit of Haleakalā on Maui, Hawaii,” NASA officials said in a statement.

    Pann-STARSR1 Telescope
    Pann-STARRS1 interior
    Pann-Stars 1 Telescope

    clock
    Asteroid 2014 RC will fly past Earth on September 7, 2014, as shown in this graphic.
    Credit: P. Chodas (NASA/JPL-Caltech)

    The asteroid will be very dim when it passes by Earth. Observers on the ground won’t be able to catch sight of it with the naked eye, but, weather permitting, intrepid amateur astronomers should be able to catch a glimpse of the fast-moving space rock through telescopes, according to NASA.

    You can also watch two webcasts featuring the asteroid flyby this weekend. The Slooh Community Observatory — an online organization that hosts live broadcast of celestial events — will begin their asteroid webcast on Sept. 6 at 10 p.m. EDT (0200 Sept. 7 GMT). The Virtual Telescope Project will also host a webcast featuring live images of the asteroid on Sept. 6 starting at 6 p.m. EDT (2200 GMT).

    At its close approach, the 60-foot (20 meters) asteroid will fly about 25,000 miles (40,000 km) from the center of Earth. The average radius of the Earth (the distance from the center of the planet to its surface) is about 3,959 miles (6,371 km).

    The speedy asteroid isn’t a threat to satellites orbiting Earth, and the space rock could even give scientists a special opportunity to learn more about asteroids because it will be so close to the planet, according to NASA.

    orbit
    The orbit of asteroid 2014 RC around the sun is shown in this graphic.
    Credit: NASA/JPL-Caltech

    NASA officials have also mapped out 2014 RC’s future orbits to see whether the near-Earth object might pose a threat to the planet in the future.

    “While 2014 RC will not impact Earth, its orbit will bring it back to our planet’s neighborhood in the future,” NASA officials said in the same statement. “The asteroid’s future motion will be closely monitored, but no future threatening Earth encounters have been identified.”

    Scientists have found more than 10,000 near-Earth objects in the solar system.

    See the full, with video, article here.

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