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96-543: In 1975, astronomers Clark R. Chapman , David Morrison , and Ben Zellner developed a simple taxonomic system for asteroids based on color , albedo , and spectral shape . The three categories were labelled " C " for dark carbonaceous objects, " S " for stony (siliceous) objects, and "U" for those that did not fit into either C or S. This basic division of asteroid spectra has since been expanded and clarified. A number of classification schemes are currently in existence, and while they strive to retain some mutual consistency, quite

192-575: A SpaceX Falcon 9 rocket, to be placed into a Venus -trailing Heliocentric orbit around the Sun. Orbiting between the Sun and Earth, the Sun's rays would always be behind the telescope's lens and thus never inhibit the space observatory 's ability to detect asteroids or other near-Earth objects (NEOs). From the vantage of its inner-solar system orbit around the Sun, Sentinel would be able to "pick up objects that are currently difficult, if not impossible, to see in advance from Earth", such as occurred with

288-496: A heliocentric orbit around the Sun similar to that of Venus , Sentinel's supercooled infrared detector would have helped identify dangerous asteroids and other NEOs that pose a risk of collision with Earth. In the absence of substantive planetary defense provided by governments worldwide, B612 attempted a fundraising campaign to cover the Sentinel Mission, estimated at $ 450 million for 10 years of operation. Fundraising

384-587: A brand new observatory. Schweickart stated that about "80% of what we're dealing with in Sentinel is Kepler , 15% Spitzer , 5% new, higher-performance infrared sensors ", thus concentrating its R&D funds on the critical area of cryogenically-cooled image sensor technology, producing what it terms will be the most sensitive type of asteroid-finding telescope ever built. Data gathered by Sentinel would be provided through existing scientific data-sharing networks that include NASA and academic institutions such as

480-403: A catastrophic impact over an inhabited area that could kill millions, a point made near the video's end. During the first decade of the 2000s, there were serious concerns the 325 metres (1,066 ft) wide asteroid 99942 Apophis posed a risk of impacting Earth in 2036. Preliminary, incomplete data by astronomers using ground-based sky surveys resulted in the calculation of a Level 4 risk on

576-467: A far higher resolution than ECAS (see Tholen classification above) , and was able to resolve a variety of narrow spectral features. However, a somewhat smaller range of wavelengths (0.44 μm to 0.92 μm) was observed. Also, albedos were not considered. Attempting to keep to the Tholen taxonomy as much as possible given the differing data, asteroids were sorted into the 26 types given below. As for

672-414: A far higher resolution than ECAS (see Tholen classification above) , and was able to resolve a variety of narrow spectral features. However, a somewhat smaller range of wavelengths (0.44 μm to 0.92 μm) was observed. Also, albedos were not considered. Attempting to keep to the Tholen taxonomy as much as possible given the differing data, asteroids were sorted into the 26 types given below. As for

768-522: A few asteroids are sorted into different classes depending on the particular scheme. This is due to the use of different criteria for each approach. The two most widely used classifications are described below: The Small Solar System Objects Spectroscopic Survey (S OS or S3OS2, also known as the Lazzaro classification ) observed 820 asteroids, using the former ESO 1.52-metre telescope at La Silla Observatory during 1996–2001. This survey applied both

864-465: A few asteroids are sorted into different classes depending on the particular scheme. This is due to the use of different criteria for each approach. The two most widely used classifications are described below: The Small Solar System Objects Spectroscopic Survey (SOS or S3OS2, also known as the Lazzaro classification ) observed 820 asteroids, using the former ESO 1.52-metre telescope at La Silla Observatory during 1996–2001. This survey applied both

960-416: A few minutes. These classification schemes are expected to be refined and/or replaced as further research progresses. However, for now the spectral classification based on the two above coarse resolution spectroscopic surveys from the 1990s is still the standard. Scientists have been unable to agree on a better taxonomic system, largely due to the difficulty of obtaining detailed measurements consistently for

1056-415: A few minutes. These classification schemes are expected to be refined and/or replaced as further research progresses. However, for now the spectral classification based on the two above coarse resolution spectroscopic surveys from the 1990s is still the standard. Scientists have been unable to agree on a better taxonomic system, largely due to the difficulty of obtaining detailed measurements consistently for

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1152-484: A fraction of a second as nearly 160 million tonnes of limestone and bedrock were uplifted, creating its crater rim on formerly flat terrain. The asteroid that produced the Barringer Crater was only about 46 metres (151 ft) in size; however it impacted the ground at a velocity of 12.8 km/s (29,000 mph) and struck with an impact energy of 10 megatonnes of TNT (42 PJ)—about 625 times greater than

1248-610: A graduate degree in solid state and semiconductor physics at the University of California at Berkeley . Dr. Marc W. Buie (b. 1958) is the foundation's Sentinel Mission Scientist, and as well a U.S. astronomer at Lowell Observatory in Flagstaff, Arizona . Buie received his B.Sc. in physics from Louisiana State University in 1980 and earned his Ph.D. in Planetary Science from the University of Arizona in 1984. He

1344-707: A joint appointment with the Joint Institute for Laboratory Astrophysics at the University of Colorado . Lu performed postdoctoral fellow work at the Institute for Astronomy in Honolulu, Hawaii from 1992 until 1995 before being selected for NASA's Astronaut Corps in 1994. Lu developed a number of new theoretical advances, which have provided for the first time a basic understanding of the underlying physics of solar flares . Besides his work on solar flares he has published journal articles and scientific papers on

1440-455: A lack of ownership, priority and funding that governments have assigned to asteroid threats, also stating on a different occasion "We're the only ones taking it seriously." According to another B612 board member, Rusty Schweickart, "The good news is, you can prevent it—not just get ready for it! The bad news is, it's hard to get anybody to pay attention to it when there are potholes in the road." After providing earlier Congressional testimony on

1536-641: A large dynamic catalog of such objects that would help identify dangerous Earth-impactors, deemed a necessary precursor to mounting any asteroid deflection mission. In March and April 2013, several weeks after the Chelyabinsk meteor explosion injured some 1,500 people, the U.S. Congress held hearings for "...the Risks, Impacts and Solutions for Space Threats". They received testimony from B612 head Ed Lu (see video at right), as well as Dr. Donald K. Yeomans, head of NASA's NEO Program Office, Dr. Michael A'Hearn of

1632-530: A large sample of asteroids (e.g. finer resolution spectra, or non-spectral data such as densities would be very useful). Some groupings of asteroids have been correlated with meteorite types : Clark R. Chapman The B612 Foundation is a private nonprofit foundation headquartered in Mill Valley, California , United States, dedicated to planetary science and planetary defense against asteroids and other near-Earth object (NEO) impacts . It

1728-562: A legislated mandate for planetary protection , not being permitted to request it. Feeling it would be imprudent to continue waiting for substantive government or United Nations action, B612 began a fundraising campaign in 2012 to cover the approximate US$ 450 million cost for the development, launch and operations of an asteroid-finding space telescope , to be called Sentinel , with a goal of raising $ 30 to $ 40 million per year. The space observatory 's objective would be to accurately survey NEOs from an orbit similar to that Venus, creating

1824-588: A mass of 1,500 kilograms (3,300 lb) and would orbit the Sun at a distance of 0.6 to 0.8 astronomical units (90,000,000 to 120,000,000 km; 56,000,000 to 74,000,000 mi) approximately the same orbital distance as Venus , employing infrared astronomy to identify asteroids against the cold of outer space. Sentinel would scan in the 7- to 15-micron wavelength band across a 5.5 by 2-degree field of view. Its sensor array would consist of 16 detectors with coverage scanning "a 200-degree, full-angle field of regard". B612, working in partnership with Ball Aerospace,

1920-468: A number of technical obstacles. Nuclear explosives were seen as "too risky and unpredictable" for several reasons, warranting the view that gently altering an asteroid's trajectory was the safest approach—but also a method requiring years of advance warning to successfully accomplish. The October 2001 asteroid deflection workshop participants created the "B612 Project" to further their research. Schweickart, along with Drs. Hut, Lu and Chapman, then formed

2016-682: A public forum moderated by Neil deGrasse Tyson not far from the United Nations Headquarters . The panel urged the global community to adopt further important steps for planetary defense against NEO impacts. Their recommendations included: The Sentinel Mission program was the cornerstone of the B612 Foundation's earlier efforts, with its preliminary design and system architecture level reviews planned for 2014, and its critical design review to be conducted in 2015. The infrared telescope would be launched atop

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2112-461: A simple taxonomic system for asteroids based on color , albedo , and spectral shape . The three categories were labelled " C " for dark carbonaceous objects, " S " for stony (siliceous) objects, and "U" for those that did not fit into either C or S. This basic division of asteroid spectra has since been expanded and clarified. A number of classification schemes are currently in existence, and while they strive to retain some mutual consistency, quite

2208-496: A single Air Force Next-Generation Bomber . The $ 450 million cost estimate is composed of $ 250 million to create Sentinel, plus another $ 200 million for 10 years of operations. In explaining the Foundation's bypassing of possible governmental grants for such a mission, Dr. Lu stated their public fundraising appeal is being driven by "[t]he tragedy of the commons: When it's everybody's problem, it's nobody's problem", referring to

2304-476: A single type was assigned to any particular asteroid. The characterization of an asteroid includes the measurement of its color indices derived from a photometric system . This is done by measuring the object's brightness through a set of different, wavelength-specific filters, so-called passbands. In the UBV photometric system , which is also used to characterize distant objects in addition to classical asteroids,

2400-427: A single type was assigned to any particular asteroid. The characterization of an asteroid includes the measurement of its color indices derived from a photometric system . This is done by measuring the object's brightness through a set of different, wavelength-specific filters, so-called passbands. In the UBV photometric system , which is also used to characterize distant objects in addition to classical asteroids,

2496-612: A six-hour spacewalk outside the station performing construction work. During his three missions he logged a total of 206 days in space. His education includes an electrical engineering degree from Cornell University , and a Ph.D. in applied physics from Stanford University . Lu became a specialist in solar physics and astrophysics as a visiting scientist at the High Altitude Observatory based in Boulder, Colorado, from 1989 until 1992. In his final year, he held

2592-576: A wide range of topics including cosmology , solar oscillations , statistical mechanics , plasma physics , near-Earth asteroids , and is also a co-inventor of the gravitational tractor concept of asteroid deflection . In 2007 Lu retired from NASA to become the Program Manager on Google 's Advanced Projects Team , and also worked with Liquid Robotics as its Chief of Innovative Applications, and at Hover Inc. as its chief technology officer . While still at NASA during 2002 Lu co-founded

2688-438: Is a greater risk of large casualties arising from a mid-sized asteroid impact. However, as of the early 2010s, only about a half of one per cent of Tunguska-type NEOs had been located by astronomers using ground-based telescope surveys. The need for an asteroid detection program has been compared to the need for monsoon, typhoon, and hurricane preparedness. As the B612 Foundation and other organizations have publicly noted, of

2784-529: Is also one of the co-discoverers of Pluto's new moons, Nix and Hydra (Pluto II and Pluto III) discovered in 2005. Buie has worked with the Deep Ecliptic Survey team who have been responsible for the discovery of over a thousand such distant objects. He also studies the Kuiper Belt and transitional objects such as 2060 Chiron and 5145 Pholus , as well as the occasional comets as with

2880-482: Is led mainly by scientists, former astronauts and engineers from the Institute for Advanced Study , Southwest Research Institute , Stanford University , NASA and the space industry . As a non-governmental organization it has conducted two lines of related research to help detect NEOs that could one day strike the Earth , and find the technological means to divert their path to avoid such collisions. It also assisted

2976-472: Is the B612 Foundation's Sentinel Program Architect, as well as a physicist, academic and a former executive-level manager at NASA , the U.S. space agency. He is a professor of Aeronautics and Astronautics at Stanford University and has been engaged in space-related research as well as program, project and executive management for more than 35 years including 20 years with NASA , culminating his career there as director of NASA's Ames Research Center . At Ames he

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3072-624: Is the chairman of the B612 Foundation's Sentinel Standing Review Team (SSRT), and a former executive-level manager at NASA . He served with NASA for 30 years, including his position as Associate Director for Flight Programs and Mission Assurance at their Jet Propulsion Laboratory (JPL) organization, and "has been at the forefront in leading many of the most successful U.S. space missions, including Galileo's mission to Jupiter, Cassini–Huygens mission to Saturn , development of Genesis, Stardust , Mars 2001 Odyssey , Mars Exploration Rovers , SPITZER and Galaxy Evolution Explorer programs." In 2001 he

3168-797: The American Institute of Aeronautics and Astronautics 's Von Karman Medal . Hubbard was elected to the International Academy of Astronautics , is a Fellow of the American Institute of Aeronautics and Astronautics, has authored more than 50 scientific papers on research and technology and also holds the Carl Sagan Chair at the SETI Institute . His education includes an undergraduate degree in physics and astronomy at Vanderbilt University and

3264-735: The Association of Space Explorers in helping the United Nations establish the International Asteroid Warning Network , as well as a Space Missions Planning Advisory Group to provide oversight on proposed asteroid deflection missions. In 2012, the foundation announced it would design and build a privately financed asteroid-finding space observatory , the Sentinel Space Telescope , to be launched in 2017–2018. Once stationed in

3360-522: The Chelyabinsk meteor of 2013 that went undetected until its explosion over Chelyabinsk Oblast , Russia . The Sentinel Mission was planned to provide an accurate dynamic catalog of asteroids and other NEOs made available to scientists worldwide from the International Astronomical Union 's Minor Planet Center , the data collected would calculate the risk of impact events with our planet, allowing for asteroid deflection by

3456-589: The Eight-Color Asteroid Survey ( ECAS ) in the 1980s, in combination with albedo measurements. The original formulation was based on 978 asteroids. The Tholen scheme includes 14 types with the majority of asteroids falling into one of three broad categories, and several smaller types (also see § Overview of Tholen and SMASS above) . The types are, with their largest exemplars in parentheses: The Tholen taxonomy may encompass up to four letters (e.g. "SCTU"). The classification scheme uses

3552-508: The Eight-Color Asteroid Survey ( ECAS ) in the 1980s, in combination with albedo measurements. The original formulation was based on 978 asteroids. The Tholen scheme includes 14 types with the majority of asteroids falling into one of three broad categories, and several smaller types (also see § Overview of Tholen and SMASS above) . The types are, with their largest exemplars in parentheses: The Tholen taxonomy may encompass up to four letters (e.g. "SCTU"). The classification scheme uses

3648-655: The Mars Pathfinder mission with its airbag landing system and was the manager for their highly successful Lunar Prospector Mission . Prior to joining NASA, Hubbard led a small start-up high technology company in the San Francisco Bay Area and was a staff scientist at the Lawrence Berkeley National Laboratory . Hubbard has received many honors including NASA's highest award, their Distinguished Service Medal , and

3744-542: The Minor Planet Center in Cambridge, Massachusetts . Given the satellite's telescopic accuracy, Sentinel's data may have proven valuable for other possible future missions, such as asteroid mining . B612 was attempting to raise approximately $ 450M to fund the development, launch and operational costs of the telescope, about the cost of a complex freeway interchange , or approximately $ 100M less than

3840-478: The Torino Scale impact hazard chart . In July 2005, B612 formally asked NASA to investigate the possibility that the asteroid's post-2029 orbit could be in orbital resonance with Earth, which would increase the likelihood of a future impact. The Foundation also asked NASA to investigate whether a transponder should be placed on the asteroid to enable more accurate tracking of how its orbit would be changed by

3936-694: The Voyager space probes program , NASA's Medal for Outstanding Leadership in 1991 for Galileo, and again in 1999 for the Cassini-Hygens mission. In 1997 Aviation Week and Space Technology presented its Laurels Award to him for outstanding achievement in the field of space. He also earned the American Astronomical Society 's 2005 Randolph Lovelace II Award for his management of all Jet Propulsion Laboratory and NASA robotic science spacecraft missions. Dr. G. Scott Hubbard

Asteroid spectral types - Misplaced Pages Continue

4032-645: The Yarkovsky effect . By 2008, B612 had provided estimates on a 30 kilometers-wide corridor, called a "path of risk", that would extend across the Earth's surface if an impact were to occur, as part of its effort to develop viable deflection strategies . The calculated risk-path extended from Kazakhstan across southern Russia through Siberia, across the Pacific, then right between Nicaragua and Costa Rica , crossing northern Colombia and Venezuela , and ending in

4128-518: The bomb that destroyed the city of Hiroshima during World War II. Tsunamis can also occur after a medium-sized or larger asteroid impacts an ocean surface or other large body of water. The probability of a mid-sized asteroid (similar to the one that destroyed the Tunguska River area of Russia in 1908 ) hitting Earth during the 21st century has been estimated at 30%. Since the Earth is currently more populated than in previous eras, there

4224-448: The near-Earth objects (NEOs) that can pose a threat to Earth, and to also fully develop impact avoidance capabilities. That recommended level of budgetary support would permit up to 10–20 years of advance warning in order to create a sufficient window for the required trajectory deflection. Their recommendations were made to a NASA Advisory Council, but were ultimately unsuccessful in obtaining Congressional funding due to NASA, lacking

4320-525: The ASE, worked with COPUOS since 2001 to establish international involvement for both impact disaster responses, and on deflection missions to prevent impact events. According to Foundation Chair Emeritus Rusty Schweickart in 2013, "No government in the world today has explicitly assigned the responsibility for planetary protection to any of its agencies". In October 2013, COPUOS's Scientific and Technical Subcommittee approved several measures, later approved by

4416-548: The Atlantic just before reaching Africa. At that time, a computer simulation estimated Apophis's hypothetical impact in countries, such as Colombia and Venezuela, could have resulted in more than 10 million casualties. Alternately, an impact in the Atlantic or Pacific oceans could produce a deadly tsunami over 240 metres (about 800 ft) in height, capable of destroying many coastal areas and cities. A series of later, more accurate observations of 99942 Apophis, combined with

4512-520: The B612 Foundation on October 7, 2002, with its first goal being to "significantly alter the orbit of an asteroid in a controlled manner". Schweickart became an early public face of the foundation and served as chairman on its board of directors . In 2010, as part of an ad hoc task force on planetary defense, he advocated increasing NASA's annual budget by $ 250M–$ 300 million over a 10-year period (with an operational maintenance budget of up to $ 75 million per year after that) in order to more fully catalog

4608-483: The B612 Foundation, later serving as its Chair and in 2014 is currently its chief executive officer . Lu holds a commercial pilot license with multi-engine instrument ratings, accumulating some 1,500 hours of flight time. Among his honors are NASA's highest awards, its Distinguished Service and Exceptional Service medals , as well as the Russian Gagarin, Komorov and Beregovoy Medals . Thomas R. Gavin

4704-424: The Earth as bolides , (fireballs), often with little notice. During an average 24-hour period, the Earth sweeps through some 100 million particles of interplanetary dust and pieces of cosmic debris, only a very minor amount of which arrives on the ground as meteorites. The larger in size asteroids or other near-Earth objects (NEOs) are, the less frequently they impact the planet's atmosphere—large meteors seen in

4800-579: The Sentinel Standing Review Team (SSRT), plus Public Relations. Edward Tsang "Ed" Lu ( Chinese : 盧傑 ; pinyin : Lú Jié ; born July 1, 1963) is a co-founder and the chief executive officer of the B612 Foundation, and as well, a U.S. physicist and a former NASA astronaut . He is a veteran of two Space Shuttle missions and an extended stay aboard the International Space Station which included

4896-539: The Tholen and Bus–Binzel (SMASS) taxonomy to the observed objects, many of which had previously not been classified. For the Tholen-like classification, the survey introduced a new "Caa-type", which shows a broad absorption band associated indicating an aqueous alteration of the body's surface. The Caa class corresponds to Tholen's C-type and to the SMASS ' hydrated Ch-type (including some Cgh-, Cg-, and C-types), and

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4992-427: The Tholen and Bus–Binzel (SMASS) taxonomy to the observed objects, many of which had previously not been classified. For the Tholen-like classification, the survey introduced a new "Caa-type", which shows a broad absorption band associated indicating an aqueous alteration of the body's surface. The Caa class corresponds to Tholen's C-type and to the SMASS ' hydrated Ch-type (including some Cgh-, Cg-, and C-types), and

5088-465: The Tholen taxonomy, the majority of bodies fall into the three broad C, S, and X categories, with a few unusual bodies categorized into several smaller types (also see § Overview of Tholen and SMASS above) : A significant number of small asteroids were found to fall in the Q , R , and V types, which were represented by only a single body in the Tholen scheme. In the Bus and Binzel SMASS scheme only

5184-416: The Tholen taxonomy, the majority of bodies fall into the three broad C, S, and X categories, with a few unusual bodies categorized into several smaller types (also see § Overview of Tholen and SMASS above) : A significant number of small asteroids were found to fall in the Q , R , and V types, which were represented by only a single body in the Tholen scheme. In the Bus and Binzel SMASS scheme only

5280-853: The UN General Assembly in December, to deal with terrestrial asteroid impacts, including the creation of an International Asteroid Warning Network (IAWN) plus two advisory groups: the Space Missions Planning Advisory Group (SMPAG), and the Impact Disaster Planning Advisory Group (IDPAG). The IAWN warning network will act as a clearinghouse for shared information on dangerous asteroids and for any future terrestrial impact events that are identified. The Space Missions Planning Advisory Group will coordinate joint studies of

5376-673: The UN is needed, said Schweickart, to guide the policymakers of its member nations on several important NEO-related aspects. However, as asserted by the Foundation, the new UN measures only constitute a starting point. To be effective they will need to be enhanced by further policies and resources implemented at both the national and supernational levels. At the time of the UN's policy adoption in New York City, Schweickart and four other ASE members, including B612 head Ed Lu and strategic advisers Dumitru Prunariu and Tom Jones participated in

5472-493: The University of Maryland and co-chair of a 2009 U.S. National Research Council study on asteroid threats, plus others. The difficulty of quickly intercepting an imminent asteroid threat to Earth was made apparent during the testimony: REP. STEWART: ... are we technologically capable of launching something that could intercept [an asteroid with 2 years of advance warning]? ... DR. A'HEARN: No. If we had spacecraft plans on

5568-568: The aftermath of the February 2013 Chelyabinsk meteor explosion —where an approximate 20 metres (66 ft) asteroid entered the atmosphere undetected at about Mach 60 , becoming a brilliant superbolide meteor before exploding over Chelyabinsk, Russia —the B612 foundation experienced a "surge of interest" in its project to detect asteroids, with a corresponding increase in funding donations. After providing Congressional testimony Dr. Lu noted that

5664-454: The alteration of an asteroid's spin rate, as well as changing the orbit of one part of a binary asteroid pair. Following the seminar's round-table discussions the workshop generally agreed that the vehicle of choice (needed to deflect an asteroid) would be powered by a low-thrust ion plasma engine. Landing a nuclear-powered plasma engined pusher vehicle on the asteroid's surface was seen as promising, an early proposal that would later encounter

5760-599: The auspices of the Comprehensive Nuclear-Test-Ban Treaty Organization , which monitors the planet for nuclear explosions. Dr. Brown's UWO study used infrasound signals generated by asteroids that released more than a kiloton of TNT explosive force. The study suggested that "city-killer" type impact events similar to the Tunguska event of 1908 actually occur on average about once a century instead of every thousand years, as

5856-705: The books already, that would take a year—I mean a typical small mission ... takes four years from approval to start to launch ... As a result of a set of hearings by the NASA Advisory Committee following the Chelyabinsk explosion in 2013, in conjunction with a White House request to double its budget, NASA's Near Earth Object Program funding was increased to $ 40.5 M/year in its FY2014 (Fiscal Year 2014) budget. It had previously been increased to $ 20.5 M/year in FY2012 (about 0.1% of NASA's annual budget at

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5952-530: The different types of natural catastrophes that can occur on our planet, asteroid strikes are the only one that the world now has the technical capability to prevent. B612 is one of several organizations to propose detailed dynamic surveys of NEOs and preventative measures such as asteroid deflection. Other groups include Chinese researchers, NASA in the United States, NEOShield in Europe, as well as

6048-714: The international Spaceguard Foundation . In December 2009 Roscosmos Russian Federal Space Agency director Anatoly Perminov proposed a deflection mission to the 325-metre-wide (1,066 ft) asteroid 99942 Apophis , which at the time had been thought to pose a risk of collision with Earth. The Foundation evolved from an informal one-day workshop on asteroid deflection strategies during October 2001, organized by Dutch astrophysicist Piet Hut along with physicist and then-U.S. astronaut Ed Lu , presented at NASA's Johnson Space Center in Houston, Texas. Twenty researchers participated, principally from various NASA facilities plus

6144-505: The issue Schweickart was dismayed to hear from congressional staff members that, while U.S. lawmakers involved in the hearing understood the seriousness of the threat, they would likely not legislate funding for planetary defense as "making the deflection of asteroids a priority might backfire in [their] reelection campaigns". The Foundation intended to launch Sentinel in 2017–2018, with initiation of data transfer for on- Earth processing anticipated no later than 6 months afterwards. In

6240-499: The journals Science and Nature , was used to produce a short computer-animated video that was presented to the media at the Seattle Museum of Flight . The nearly one and a half minute video displayed a rotating globe with the impact points of about 25 asteroids measuring more than one, and up to 600 kilotons of blast force, that struck the Earth from 2000 to 2013 (for comparison, the nuclear bomb that destroyed Hiroshima

6336-517: The letter "I" for "inconsistent" spectral data, and should not be confused with a spectral type. An example is the Themistian asteroid 515 Athalia , which, at the time of classification was inconsistent, as the body's spectrum and albedo was that of a stony and carbonaceous asteroid, respectively. When the underlying numerical color analysis was ambiguous, objects were assigned two or three types rather than just one (e.g. "CG" or "SCT"), whereby

6432-457: The letter "I" for "inconsistent" spectral data, and should not be confused with a spectral type. An example is the Themistian asteroid 515 Athalia , which, at the time of classification was inconsistent, as the body's spectrum and albedo was that of a stony and carbonaceous asteroid, respectively. When the underlying numerical color analysis was ambiguous, objects were assigned two or three types rather than just one (e.g. "CG" or "SCT"), whereby

6528-492: The many online videos recorded of the asteroid's explosion over Chelyabinsk made a significant impact on millions of viewers worldwide, saying "There's nothing like a hundred YouTube videos to do that." In 2014 eight key staff positions were designated, covering the offices of the chief executive officer (CEO), chief operating officer (COO), Sentinel Program Architecture (SPA), Sentinel Mission Direction (SMD), Sentinel Program Management (SPM), Sentinel Mission Science (SMS) and

6624-514: The non-profit Southwest Research Institute , but as well from the University of California, University of Michigan, and the Institute for Independent Study. All were interested in contributing to the proposed creation of an asteroid deflection capability. The seminar participants included Rusty Schweickart , a former Apollo astronaut , and Clark Chapman , a planetary scientist . Among the proposed experimental research missions discussed were

6720-445: The presentation, alongside former NASA astronauts Dr. Tom Jones and Apollo 8 astronaut Bill Anders , Foundation head Ed Lu explained that the frequency of dangerous asteroid impacts hitting Earth was from three to ten times greater than previously believed a dozen or so years ago (earlier estimates had pegged the odds as one per 300,000 years). The latest reassessment is based on worldwide infrasound signatures recorded under

6816-590: The recent Deep impact mission that travelled to Comet Tempel 1 , and near-Earth asteroids with the occasional use of the Hubble and Spitzer Space Telescopes . Buie also assists in the development of advanced astronomical instrumentation. Tholen classification An asteroid spectral type is assigned to asteroids based on their reflectance spectrum , color , and sometimes albedo . These types are thought to correspond to an asteroid's surface composition. For small bodies that are not internally differentiated ,

6912-602: The recovery of previously unseen data, revised the odds of a collision in 2036 as being virtually nil, and effectively ruled it out. B612 Foundation members assisted the Association of Space Explorers (ASE) in helping obtain United Nations (UN) oversight of NEO tracking and deflection missions through the UN's Committee On the Peaceful Uses of Outer Space (UN COPUOS) along with COPUOS's Action Team 14 (AT-14) expert group. Several members of B612, also members of

7008-453: The sequence of types reflects the order of increasing numerical standard deviation, with the best fitting spectral type mentioned first. The Tholen taxonomy also has additional notations, appended to the spectral type. The letter "U" is a qualifying flag, used for asteroids with an "unusual" spectrum, that falls far from the determined cluster center in the numerical analysis. The notation ":" (single colon) and "::" (two colons) are appended when

7104-452: The sequence of types reflects the order of increasing numerical standard deviation, with the best fitting spectral type mentioned first. The Tholen taxonomy also has additional notations, appended to the spectral type. The letter "U" is a qualifying flag, used for asteroids with an "unusual" spectrum, that falls far from the determined cluster center in the numerical analysis. The notation ":" (single colon) and "::" (two colons) are appended when

7200-473: The skies are extremely rare, while medium-sized ones are less so, and much smaller ones are more commonplace. Although stony asteroids often explode high in the atmosphere, some objects, especially iron-nickel meteors and other types descending at a steep angle, can explode close to ground level or even directly impact onto land or sea. In the U.S. State of Arizona , the 1,200-metre-wide (3,900 ft) Meteor Crater (officially named Barringer Crater) formed in

7296-611: The spectral data is "noisy" or "very noisy", respectively. For example, the Mars-crosser 1747 Wright has an "AU:" class, which means that it is an A-type asteroid , though with an unusual and noisy spectrum. This is a more recent taxonomy introduced by American astronomers Schelte Bus and Richard Binzel in 2002, based on the Small Main-Belt Asteroid Spectroscopic Survey (SMASS) of 1,447 asteroids. This survey produced spectra of

7392-444: The spectral data is "noisy" or "very noisy", respectively. For example, the Mars-crosser 1747 Wright has an "AU:" class, which means that it is an A-type asteroid , though with an unusual and noisy spectrum. This is a more recent taxonomy introduced by American astronomers Schelte Bus and Richard Binzel in 2002, based on the Small Main-Belt Asteroid Spectroscopic Survey (SMASS) of 1,447 asteroids. This survey produced spectra of

7488-454: The surface and internal compositions are presumably similar, while large bodies such as Ceres and Vesta are known to have internal structure. Over the years, there has been a number of surveys that resulted in a set of different taxonomic systems such as the Tholen , SMASS and Bus–DeMeo classifications. In 1975, astronomers Clark R. Chapman , David Morrison , and Ben Zellner developed

7584-506: The technologies for deflection missions, and as well provide oversight of actual missions. This is due to deflection missions typically involving a progressive movement of an asteroid's predicted impact point across the surface of the Earth (and also across the territories of uninvolved countries) until the NEO is deflected either ahead of, or behind the planet at the point their orbits intersect. An initial framework of international cooperation at

7680-575: The three basic filters are: In an observation, the brightness of an object is measured twice through a different filter. The resulting difference in magnitude is called the color index . For asteroids, the U−B or B−V color indices are the most common ones. In addition, the V−R, V−I and R−I indices, where the photometric letters stand for visible (V), red (R) and infrared (I), are also used. A photometric sequence such as V–R–B–I can be obtained from observations within

7776-483: The three basic filters are: In an observation, the brightness of an object is measured twice through a different filter. The resulting difference in magnitude is called the color index . For asteroids, the U−B or B−V color indices are the most common ones. In addition, the V−R, V−I and R−I indices, where the photometric letters stand for visible (V), red (R) and infrared (I), are also used. A photometric sequence such as V–R–B–I can be obtained from observations within

7872-502: The time), from an average of about $ 4 M/year between 2002 and 2010. On Earth Day , April 22, 2014, the B612 Foundation formally presented a revised assessment on the frequency of "city-killer" type impact events, based on research led by Canadian planetary scientist Peter Brown of the University of Western Ontario 's (UWO) Centre for Planetary Science and Exploration . Dr. Brown's analysis, "A 500-Kiloton Airburst Over Chelyabinsk and An Enhanced Hazard from Small Impactors", published in

7968-418: The use of gravity tractors to divert their trajectories away from Earth. In order to communicate with the spacecraft while it is orbiting the Sun (at about the same distance as Venus), which can be at times as far as 270 million kilometres (170 million miles) from Earth, the B612 Foundation entered into a Space Act Agreement with NASA for the use of their deep space telecommunication network . Sentinel

8064-426: The wavelength 0.45–2.45 micrometers. This system of 24 classes introduces a new "Sv"-type and is based upon a principal component analysis , in accordance with the SMASS taxonomy, which itself is based upon the Tholen classification. The most widely used taxonomy is that of David J. Tholen , first proposed in 1984. This classification was developed from broad band spectra (between 0.31 μm and 1.06 μm) obtained during

8160-425: The wavelength 0.45–2.45 micrometers. This system of 24 classes introduces a new "Sv"-type and is based upon a principal component analysis , in accordance with the SMASS taxonomy, which itself is based upon the Tholen classification. The most widely used taxonomy is that of David J. Tholen , first proposed in 1984. This classification was developed from broad band spectra (between 0.31 μm and 1.06 μm) obtained during

8256-580: Was a post-doctoral fellow at the University of Hawaii from 1985 to 1988. From 1988 to 1991, he worked at the Space Telescope Science Institute where he assisted in the planning of the first planetary observations made by the Hubble Space Telescope . Since 1983, Pluto and its moons have been a central theme of the research done by Buie, who has published over 85 scientific papers and journal articles. He

8352-772: Was appointed associate director for flight projects and mission success for NASA's Jet Propulsion Laboratory in May 2001. This was a new position created to provide the JPL Director's Office with oversight of flight projects. He later served as interim director for Solar System exploration. Previously, he was director of JPL's Space Science Flight Projects Directorate, which oversaw the Genesis, Mars 2001 Odyssey, Mars rovers, Spitzer Space Telescope and GALEX projects. He also served as deputy director of JPL's Space and Earth Science Programs Directorate beginning in December 1997. In June 1990 he

8448-702: Was appointed spacecraft system manager for the Cassini–Huygens mission to Saturn, and retained that position until the project's successful launch in 1997. From 1968 to 1990 he was a member of the Galileo and Voyager project offices responsible for mission assurance. He received his bachelor's degree in chemistry from Villanova University in Pennsylvania in 1961. Gavin has been honored on a number of occasions for exceptional work, receiving NASA's Distinguished and Exceptional Service Medals in 1981 for his work on

8544-467: Was assigned to 106 bodies or 13% of the surveyed objects. In addition, S3OS2 uses the K-class for both classification schemes, a type which does not exist in the original Tholen taxonomy. The Bus-DeMeo classification is an asteroid taxonomic system designed by Francesca DeMeo , Schelte Bus and Stephen Slivan in 2009. It is based on reflectance spectrum characteristics for 371 asteroids measured over

8640-410: Was assigned to 106 bodies or 13% of the surveyed objects. In addition, S3OS2 uses the K-class for both classification schemes, a type which does not exist in the original Tholen taxonomy. The Bus-DeMeo classification is an asteroid taxonomic system designed by Francesca DeMeo , Schelte Bus and Stephen Slivan in 2009. It is based on reflectance spectrum characteristics for 371 asteroids measured over

8736-439: Was constructing Sentinel's 51 cm aluminum mirror, designed for a large field of view with its infrared sensors cooled to 40  K (−233.2  °C ) using Ball's two-stage, closed-Stirling-cycle cryocooler . B612 aimed to produce its space telescope at a significantly lower cost than traditional space science programs by making use of space hardware systems previously developed for earlier programs, rather than designing

8832-619: Was designed to perform continuous observation and analysis during its planned 6 + 1 ⁄ 2 -year operational life, although B612 anticipates it may continue to function for up to 10 years. Using its 51-centimetre (20 in) telescope mirror with sensors built by Ball Aerospace (makers of the Hubble Space Telescope 's instruments), its mission would be to catalog 90% of asteroids with diameters larger than 140 metres (460 ft). There were also plans to catalog smaller Solar System objects as well. The space observatory would measure 7.7 metres (25 ft) by 3.2 metres (10 ft) with

8928-456: Was equivalent to about 16 kilotons of TNT blast force). Of those impacts between 2000 and 2013, eight of them were as large, or larger, than the Hiroshima bomb. Only one of the asteroids, 2008 TC 3 , was detected in advance , some 19 hours before exploding in the atmosphere. As was the case with the 2013 Chelyabinsk meteor , no warnings were issued for any of the other impacts. At

9024-401: Was once previously believed. The 1908 event occurred in the remote, sparsely populated Tunguska area of Siberia , Russia, and is attributed to the likely airburst explosion of an asteroid or comet that destroyed some 80 million trees over 2,150 square kilometres (830 sq mi) of forests. The higher frequency of these types of events is interpreted as meaning that "blind luck" has mainly prevented

9120-690: Was responsible for overseeing the work of some 2,600 scientists, engineers and other staff. Currently on the SpaceX Safety Advisory Panel, he previously served as NASA's sole representative on the Space Shuttle Columbia Accident Investigation Board , and also as their first Mars Exploration Program director in 2000, successfully restructuring the entire Mars program in the wake of earlier serious mission failures. Hubbard founded NASA's Astrobiology Institute in 1998; conceived

9216-579: Was unsuccessful, and the program was cancelled in 2017, with the Foundation pursuing a constellation of smaller satellites instead. The B612 Foundation is named for the asteroid home of the eponymous hero of Antoine de Saint-Exupéry 's 1943 book The Little Prince . When an asteroid enters the planet's atmosphere it becomes known as a ' meteor '; those that survive and fall to the Earth's surface are then called ' meteorites '. While basketball-sized meteors occur almost daily, and compact car-sized ones about yearly, they usually burn up or explode high above

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