21 December 2008

Head-Sized Meterorite Part Found.

Several more fragments have been found from the 10-ton asteroid that exploded over western Canada on November 20, including a head-sized piece weighing 13-kilograms (28 lbs). Imagine that landing on your house or car (or head!). University of Calgary professor Alan Hildebrand, who is leading the search estimates there could be 2,000 fragments per hectare (about 2.5 acres) in the area near where fragments were initially found. The asteroid is becoming known as the Buzzard Coulee fireball, named after the picturesque, but luckily uninhabited valley where the first pieces were located. Check out the website of Bruce McCurdy of Edmonton Space & Science Foundation and the Royal Astronomical Society of Canada, who has joined in the search for more meteorite images.
More than two dozen pieces of the asteroid have been found by researchers or members of the public. The search is focused on a 24-square-kilometer section of agricultural land along the Battle River where the scientists calculated the debris would be located.

Obama Transition team considering SSP

DynaSoar writes "President-elect Obama's transition team has published for public comment a white paper entitled Space Solar Power (SSP) — A Solution for Energy Independence & Climate Change. The paper was prepared and submitted by the Space Frontier Foundation and other citizen space advocates, and calls for the new Administration to make development of Space Solar Power a national priority. The SSP white paper was among the first ten released by the Obama transition team. It is the first and only space-related white paper released by the team to date. With 145 comments thus far, it is already among the top five most-discussed of the 20-some white papers on Change.gov."

Check out the direct link:

25 November 2008

Giant Camera Tracks Asteroids

Giant Camera Tracks Asteroids
The camera will offer sharper, broader views of the sky.
By Robert Lemos

The first of four new asteroid-tracking telescopes will come online next month in Hawaii, promising to quickly scan large swaths of the sky--thanks to the world's largest digital camera.

The project, known as the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS), aims to scan the entire sky visible from the summit of Mount Haleakala in Maui Island, Hawaii, three times a month, searching for asteroids and near-Earth objects (NEOs) as small as 300 meters in diameter. At the heart of each telescope is a 1.4-billion-pixel digital camera that can photograph broad swaths of the night sky in sharp detail.

The first prototype telescope using the camera will go online in December. This telescope will scan the night sky, searching for asteroids and comets that could pose a threat to Earth. Pan-STARRS is designed to have at least three times the collecting power of current NEO telescopes.

The Pan-STARRS's cameras, each consisting of a 40-centimeter-square array of charge-coupled devices (CCDs), bring new technology to the optics used in astronomy. Perhaps the most innovative aspect is the ability of each CCD cell to electronically shift an image to counteract atmospheric blur and deliver clearer astrophotography, says Barry Burke, a senior staff member at MIT's Lincoln Laboratory, which makes the cameras.

"The atmosphere is the limit to the quality of the image, but there is a special feature of these chips that allows them to remove some of the blur due to atmospheric effects," Burke says. "It allows the image to be shifted in any direction in the chip in a way that matches the motion of the stars and that takes out a significant part of the blur."

Known as orthogonal transfer CCD (OTCCD), the technology uses electronics to adjust the image rather than mechanically tilting a camera's lens or mirror, a more common technique used in consumer cameras that have optical image stabilization. Because the process is electronic, the technology can be distributed to each cell of the CCD array, allowing for much more granular adjustments to localized atmospheric turbulence. The result is an image that is sharper than what a ground-based observatory could produce.

The mosaic structure of the CCD camera also leads to a more reliable system and less expensive manufacturing costs, Burke says. "The chip could not possibly be made to that size, so we are forced to break the camera down into tiles," he says.

Each Pan-STARRS camera consists of an eight-by-eight array of devices, each containing an eight-by-eight array of CCD cells. The size of each cell--about six millimeters on a side--is determined by a sweet spot...

Space experts call for asteroid action plan

From: http://www.msnbc.msn.com/id/27910044/
Space experts call for asteroid action plan
Time needed to deflect asteroids, evacuate people living in impact zone
updated 11:55 a.m. ET, Tues., Nov. 25, 2008
VIENNA, Austria - Space experts are urging the United Nations to devise a plan that allows for quick action against asteroids. Rusty Schweickart, a former U.S. astronaut, says such a plan would save the time needed to deflect asteroids or evacuate people living in a possible impact zone. He says researchers will increasingly be able to predict collisions and that, for the first time in history, technical capabilities exist to prevent them. Schweickart and other experts spoke to reporters Tuesday after presenting a report on the matter to U.N. officials in Vienna.

24 November 2008

All-Sky Camera Network

One method by which meteors can be observed & tracked.

Did Asteroid Cause Ancient N.Y. Tsunami?

Long before New York City was the Big Apple, or even New Amsterdam, a giant tsunami crashed ashore.
It was 2,300 years ago. The Palisades that frame the Hudson River were whisper-quiet, the sandy beaches of Long Island and New Jersey empty, and Manhattan was still just an unbroken sylvan carpet.
Then came the mammoth wave, roaring into the serenity. No one knows for sure what caused it, but new clues found in the Hudson's silt suggest an asteroid 100 meters (330 feet) in diameter slammed into the Atlantic Ocean nearby.
While sifting through samples, Katherine Cagen of Harvard University and a team of researchers found carbon spherules -- perfectly round particles that form in the extreme pressures of an impact.
"But the main thing that closes the deal is that we looked in the spherules and found nano-diamonds," said Dallas Abbott of Columbia University, a co-author on the work. "These have only been found in impact ejecta or in meteorites."
The team found grains of several shocked minerals in the sediments as well, but the discovery remains controversial.
"To get a wave 2.5 meters high that far up the Hudson, you need a wave 20 meters high at Manhattan," said Steven Ward of the University of California, Santa Cruz. "It would've gone several hundred meters inland on Long Island; you should see evidence of this thing all over the place."
Bunch of terrific Asteroid/Tidal Wave Sims here: http://es.ucsc.edu/~ward/

$10,000 to anyone who can locate and give him the first one-kilogram chunk

This meteor was thought to generate only about 1/3 KT (from 10% luminous efficiency based on measured irradiance), which would make it significantly smaller (less than half) than 2008TC3 which impacted the atmosphere over Sudan (see earlier posts). The Canadians are apparently feverishly working to estimate the fall area and recover fragments before the first snow.

This particular meteor was thought to weigh about one to seven tonnes before it entered the Earth's atmosphere, and was five times as bright as a full moon.

He said the people with the best chance of finding pieces are the ones who heard the sonic boom made by the falling meteorite chunks.
"If you hear that, then you're probably within 30 kilometres of it."

22 November 2008

Amazing Video of Meteor over Canada

About 1730 yesterday, in Edmonton, Canada:
From: http://www.google.com/hostednews/canadianpress/article/ALeqM5jU4E6gEY14ICcUMiwnqPkveUsF3w
"I just happened to look outside facing east," he said. "All of a sudden I saw this big flash coming down and I thought somebody was playing tricks on me, like fireworks behind the house or something.
"Just before that I heard a boom. I didn't know if it was a tree against the house. It was green and blue and it was coming down pretty fast."
Gobeil said the light display eventually turned orange, yellow and red and lasted 10 seconds.
"I was waiting for it to explode," he said. "It looked similar to when we watch (news reports) in Afghanistan. When I didn't see that, I said, 'well, that's something from outer space.' I'm sure it landed way out in Winnipeg or something."
"It's exciting - both scary and really nice."

10 November 2008

Future Channel Posts new video on Space Solar Power

A new video for math and science classrooms:

To consider the space solar power concept requires an understanding of science, technology, engineering, math, energy, policy, environmental factors, and more. Space solar power is an engineering project on a scale that rivals the greatest in history. Students need to be informed and able to participate in the conversation.

Image of TC3 in Sky

A month after asteroid 2008 TC3 hit the Earth's atmosphere, the first ground-based image of the event has surfaced on the Internet. Admittedly, it's not the fireball everyone has been waiting to see, but it is visual evidence that something hit us above Sudan on October 7th. The image above was taken from a frame of video that was being recorded by Mr. Mohamed Elhassan Abdelatif Mahir in the dawn following the asteroid impact with the atmosphere. The smoky feature is the remnant of the fireball as the 3 meter-wide asteroid blasted through the upper atmosphere, eventually exploding. The long-lasting persistent train is seen hanging in the air, high altitude winds causing it to twist in the morning sunlight.
We may not have a dazzling fireball re-entry video of 2008 TC3, but this striking image provides the first ground-based evidence of the direct hit, and may help refine the search for any meteorites from the disintegrated asteroid…

27 October 2008

Energy Biz: Japan has high hopes for Space Solar Power

From: http://energycentral.fileburst.com/EnergyBizOnline/2008-5-sep-oct/Tech_Frontier_Solar_Space.pdf
Japan is working hard toadvance its laser and microwave research so that solar power generated in space can be beamed to Earth in two decades, Scientific American reported this summer. By 2030, the Japanese hope to generate 1,000 megawatts at an orbiting solar generator and transport it to Earth. To learn more about the effort, EnergyBiz e-mailed questions to Hiroaki Suzuki with the Japan Aerospace Exploration Agency, also known as JAXA. He is one of 180 Japanese scientists working on the program, according to Scientific American. It also reported that the ultimate cost of such a project could climb to tens of billions of dollars, but the Japanese are intent on mastering the technology first, and then driving down the cost to levels that are competitive.
We have investigated two types of space solar panel systems, laser and microwave.With laser-based systems, Earth-orbiting solar condenser mirrors concentrate solar energy and divert it to laser amplifiers. A direct solar pumping solid-state laser diode uses the concentrated solar energy to amplify a low-power seed laser beam. The amplified laser beam is transmitted to Earth. Thus, this type of system uses no solar cell panels. Radiators dissipate the laser generator’s waste heat into space. A ground-based photovoltaic device converts the transmitted laser beam into electricity. This system can also be used to produce hydrogen with photocatalytic hydrogen generation or water electrolysis.With microwave-based systems, primary mirrors collect solar energy that solar panels convert to electricity that powers semiconductordevices to generate a microwave beam. A ground-based rectifying antenna array collects the transmitted microwave beam and converts it into electricity that is supplied to commercial power grids.
In the elemental technology development study, a laser amplifier with a direct solar pumping solid-state laser diode made of yttrium aluminum garnet ceramic doped with neodymium and chromium is being studied. The atmospheric transmittal propertiesof a high-energy laser beam and beam-pointing technology are studied for their applications in a laser-based system. For the microwave-based system, a large-scale phased array antenna, microwave amplifier, retro-directive beam control, and rectifying antenna are being studied. For both systems, a large-scale, ultra-light reflective mirror is also studied.
In the ground energy transmission demonstration, a kilowatt-class experiment for laser and microwave system is planned and is expected to be conducted within five years.System concepts and architectures of commercial-grade microwave- and laser-based space solar panel systems have been studied for years. System concepts and architectures have been developed and associated key technologieshave been identified.
Although a preliminarycost estimate has been conducted, it includes a lot of ambiguities. We are not ready to show you our cost analysis. We expect space solar panel systems will be competitive with the existing power plants in 20 to 30 years, if the space transportation cost is considerably reduced. It should be noted that solar systems do not emit CO2, nor do they create nuclear waste.
We are proposing a roadmap that consists of a stepped approach to achieve 1-gigawatt-class commercial space solar panel systems in 20 to 30 years. That means 2030 would see the very beginning of commercial systems. We expect the ultimate percentage of electricity derived from space will be more than several tens of percent. By the way, Japanese total electricity generation was about 275 gigawatts or 990,000 gigawatt-hours in 2005.

26 October 2008

NSS PositionPaper on Space Solar Power

Exerpts From: http://www.nss.org/legislative/positions/NSS-SSP-PositionPaper.pdf
Space Solar Power: An Investment for Today – An Energy Solution for Tomorrow
October 2007
The United States and the rest of the world need to find alternative sources of energy besides fossil fuels. The National Space Society believes that one of the most important long-term solutions for meeting those energy needs is Space Solar Power (SSP), which gathers energy from sunlight in space and sends it to Earth. We believe that SSP can solve our energy and greenhouse gas emissions problems. Not just help, not just take a step in the right direction; solve. SSP can provide large quantities of energy to each and every person on Earth with very little environmental impact. The NSS recommends that SSP be considered along with ground-based solar collectors and wind turbines as a safe, renewable, and clean energy option.
Solar energy is routinely used on spacecraft today, and the solar energy available in space is literally billions of times greater than we use today. The lifetime of the sun is an estimated 4 to 5 billion years, making SSP a truly long-term energy solution. Space solar power can have an extremely small environmental footprint, perhaps competitive with ground-solar and wind, because with sufficient investments in space infrastructure, the SSP can be built from materials from space with zero terrestrial environmental impact. Only energy receivers need be built on Earth. As Earth receives only one part in 2.3 billion of the sun's output, SSP is by far the largest
potential energy source available, dwarfing all others combined. Development cost and time, of course, are considerable. This makes SSP a long-term solution rather than a short-term stop-gap, although there are some intriguing near-term possibilities.... While all viable energy options should be pursued with vigor, SSP has a number of substantial advantages over other energy sources...
All of these technologies are consistent with the laws of physics, are reasonably nearterm, and have multiple attractive approaches. However, a great deal of work is needed to develop economically competitive space solar power. The NSS encourages both the private sector and governments to devote substantial resources toward SSP research and development.
SSP deserves a place alongside ground-based solar collectors, nuclear power plants, and
wind turbines as potential solutions to energy dependence and global greenhouse-gasinduced
. If SSP is given serious consideration, NSS expects it will play a growing, and perhaps dominant, role in providing safe, clean, renewable energy for our planet for the foreseeable future and beyond.
The Vision of NSS is people living and working in thriving communities beyond the Earth, and the use of the vast resources of space for the dramatic betterment of humanity.
The Mission of NSS is to promote social, economic, technological, and political change in order to expand civilization beyond Earth, to settle space and to use the resulting resources to build a hopeful and prosperous future for humanity. Accordingly, we support steps toward this goal, including human spaceflight, commercial space development, space exploration, space applications, space resource utilization, robotic precursors, defense against asteroids, relevant science, and space settlement oriented education.

Read more about Space Solar at NSS web page: http://www.nss.org/settlement/ssp/index.htm

By the way, recently the National Space Society has constructed tremendous on-line resources for information on Space Solar and Planetary Defense can be found here:
Space Solar Library:http://www.nss.org/settlement/ssp/library/index.htm

New Space Industrialization Video & Libraries

New pro-Space Industrialization video:

US Chamber Endorses Space Solar

The appropriate policy question is: "Should the U.S. Government invest in SBSP research, as part of a diversified portfolio of renewable energy programs, including consideration of new approaches that may not have been previously studied?" Our answer to that question is yes. We must explore all potentially significant sources of sustainable energy that might contribute, even if only to a limited extent in the near term, to assurance of security and prosperity. Facing this challenge represents a responsibility not only to our own nation but also to the global community in which we live.
SBSP should be addressed through an incremental roadmap approach, involving both Government and private sector investment. This roadmap should be constructed to address at the outset key questions about SBSP, including technical viability and cost-effectiveness. The roadmap should consist of a series of milestones, each built on the availability of information generated by prior research. If research results are positive, each milestone should lead to increased government and private sector effort and investment. If justified by research findings, a move from research to demonstration projects should be initiated. Beyond this, milestones should be designed to maximize opportunities for multiple applications of research results, so that improvements in existing technologies and development of new ones could have near-term applications in addition to SBSP (e.g., communications satellite power supplies, terrestrial solar power generation).
The Space Enterprise Council of the U.S. Chamber of Commerce supports the National Security Space Office recommendation of a research program addressing space-based solar power, to explore whether or not this potential energy source could enhance commerce and security. The importance of alternative energy research is becoming increasingly clear, given the urgency of the national and global need for energy that is inexhaustible, affordable, and environmentally clean. Assuring access to energy is particularly relevant to U.S. national security, not only for supply of reliable power to deployed forces but also for avoiding international conflicts that might arise because of energy shortages.

SBSP is unusual among renewable energy options because it might satisfy all four of the following criteria critical to investment decisions: environmental cleanliness, sustainability of supply, flexibility of location, and capacity to generate continuous rather than intermittent power. The cost of SBSP-generated electricity would initially be greater than that provided by fossil fuel or nuclear power but could be comparable to other alternative energy sources, particularly for baseload power. In addition, SBSP might offer an attractive approach, not only for satisfying today's needs but also for meeting tomorrow’s much greater requirements. We cannot accurately predict environmental and other consequences of harvesting energy from natural Earthbound sources (e.g., wind, ocean current, geothermal, biofuels), when these methods are scaled up to considerably higher levels. By providing an additional source of renewable energy, SBSP might help avoid potentially negative consequences if limits to the cost-effective expansion of other renewable sources become evident. Beyond enhancement of energy production per se, SBSP might help create new economic opportunities through resultant technology advances in space launch, space utilization, and technological spin-offs applicable to a host of materials and processes. For example, SBSP research might lead to improvements in the efficiency of solar cells that power communications satellites, as well as power management systems for terrestrial solar power systems. Also, to the extent that SBSP is integrated into terrestrial solar power production, development of SBSP ground infrastructure might generate revenue even before deployment of systems in space. In this and related applications, SBSP could emerge as an enhancement for, rather than a competitor with, terrestrial solar power generation.

Space Solar News

From: http://indiapost.com/article/usnews/4044/
Targeting India on climate change is unfair: PranabSunday, 10.05.2008, 09:24pm (GMT-7)India Post News Service. Indian External Affairs Minister Pranab Mukherjee before an enlightened audience at the Asia Society in New York on Sept 30...his speech on 'India and Global Challenges: Climate Change and Energy Security', which was part of a series of talks by Asian leaders hosted by the Asia Society at its New York headquarters in conjunction with the opening of the United Nations General Assembly (UNGA) from September 22 to October 3.
"Later, during a question-answer session, the External Affairs Minister said that despite having vast deposits of thorium, India could not pursue production of nuclear energy as access to critical nuclear technology was denied to it over the last 30 years. He said India was now collaborating closely with the US to tap space solar power."
His remarks follow the call at the 2007 International Astronomical Congress for a Global Aerospace Mission in Space and Energy to realize Space Solar Power. Dr. Kalam's speech here, particularly about 40 minutes in:
And Dr. Kalam (then India's President), laid out space as among the greenest technologies, laying out the challenge of space solar power:
Perhaps significant, considering the recent headline:
Obama says India will be top priority
A stronger relationship with India and a close strategic partnership will be a 'top priority' of a Barack Obama administration, says the Democratic presidential candidate. "The US should be working with India on a range of critical issues from preventing terrorism to promoting peace and stability in Asia," Senator Obama said in an exclusive interview. "Joe Biden and I will make building a stronger relationship, including a close strategic partnership, with India a top priority." On his agenda for working with New Delhi, he said, "I also believe India is a natural strategic partner for America in the 21st century and that the US should be working with India on a range of critical issues from preventing terrorism to promoting peace and stability in Asia."
This follows earlier, and longstanding remarks of his running mate:
Biden (D-DE) called U.S. ties with India the “single most important relationship that we have to get right for our own safety's sake” (Rediff.com).
And for the United States, no relationship is more important than the one we are building with India.” — Senator Joseph Biden, November 16, 2006

Neil Tyson on CNN/D.L. Hughley Obama & Asteroids

Hillarious interview with Neil Tyson tonight on CNN late night comedy news talk show host D.L. Hughley:

25 October 2008

HR 6063 Becomes Law!

On Oct 15, the President signed HR 6063, the 2008 NASA Authorization Act into Law. Find the full text here: http://www.govtrack.us/congress/billtext.xpd?bill=h110-6063
Most significantly, it contains the following language:
(a) Reaffirmation of Policy on Surveying Near-Earth Asteroids and Comets- Congress reaffirms the policy (g)) (relating to surveying42 U.S.C. 2451set forth in section 102(g) of the National Aeronautics and Space Act of 1958 (near-Earth42 U.S.C. 2451(g)) (relating to surveying near-Earth asteroids and comets).
(b) Sense of Congress on Benefits of Near-Earth Object Program Activities- It is the sense of Congress that the near-Earth object program activities of NASA will provide benefits to the scientific and exploration activities of NASA.
Congress makes the following findings:
(1) Near-Earth objects pose a serious and credible threat to humankind, as many scientists believe that a major asteroid or comet was responsible for the mass extinction of the majority of the Earth’s species, including the dinosaurs, nearly 65,000,000 years ago.
(2) Several such near-Earth objects have only been discovered within days of the objects’ closest approach to Earth and recent discoveries of such large objects indicate that many large near-Earth objects remain undiscovered.
(3) Asteroid and comet collisions rank as one of the most costly natural disasters that can occur.
(4) The time needed to eliminate or mitigate the threat of a collision of a potentially hazardous near-Earth object with Earth is measured in decades.
(5) Unlike earthquakes and hurricanes, asteroids and comets can provide adequate collision information, enabling the United States to include both asteroid-collision and comet-collision disaster recovery and disaster avoidance in its public-safety structure.
(6) Basic information is needed for technical and policy decisionmaking for the United States to create a comprehensive program in order to be ready to eliminate and mitigate the serious and credible threats to humankind posed by potentially hazardous near-Earth asteroids and comets.
(7) As a first step to eliminate and to mitigate the risk of such collisions, situation and decision analysis processes, as well as procedures and system resources, must be in place well before a collision threat becomes known.
The Administrator shall issue requests for information on--
(1) a low-cost space mission with the purpose of rendezvousing with, attaching a tracking device, and characterizing the Apophis asteroid; and
(2) a medium-sized space mission with the purpose of detecting near-Earth objects equal to or greater than 140 meters in diameter.
Within 2 years after the date of enactment of this Act, the Director of the OSTP shall--
(1) develop a policy for notifying Federal agencies and relevant emergency response institutions of an impending near-Earth object threat, if near-term public safety is at risk; and
(2) recommend a Federal agency or agencies to be responsible for--
(A) protecting the United States from a near-Earth object that is expected to collide with Earth; and
(B) implementing a deflection campaign, in consultation with international bodies, should one be necessary.
The Administrator shall maintain a planetary radar that is comparable to the capability provided through the Deep Space Network Goldstone facility of NASA.
Congress reiterates its support for the use of the Arecibo Observatory for NASA-funded near-Earth object-related activities. The Administrator, using funds authorized in section 101(a)(1)(B), shall ensure the availability of the Arecibo Observatory’s planetary radar to support these activities until the National Academies’ review of NASA’s approach for the survey and deflection of near-Earth objects, including a determination of the role of Arecibo, that was directed to be undertaken by the Fiscal Year 2008 Omnibus Appropriations Act, is completed.
It is the sense of Congress that, since an estimated 25,000 asteroids of concern have yet to be discovered and monitored, the United States should seek to obtain commitments for cooperation from other nations with significant resources for contributing to a thorough and timely search for such objects and an identification of their characteristics.
(a) In General- Prizes can play a useful role in encouraging innovation in the development of technologies and products that can assist NASA in its aeronautics and space activities, and the use of such prizes by NASA should be encouraged.
(b) Amendments- Section 314 of the National Aeronautics and Space Act of 1958 is amended--
(1) by amending subsection (b) to read as follows:
‘(b) Topics- In selecting topics for prize competitions, the Administrator shall consult widely both within and outside the Federal Government, and may empanel advisory committees. The Administrator shall give consideration to prize goals such as the demonstration of the ability to provide energy to the lunar surface from space-based solar power systems, demonstration of innovative near-Earth object survey and deflection strategies, and innovative approaches to improving the safety and efficiency of aviation systems.’; and
(2) in subsection (i)(4) by striking ‘$10,000,000’ and inserting ‘$50,000,000’.

Canadian Asteroid Defense & Schedule of Events

Check out this new Canadian-based Global Asteroid Protection Society:


They join a long-line of organizations which have called for action:
Space Frontier Foundation: https://webmail.hq.af.mil/exchweb/bin/redir.asp?URL=http://www.space-frontier.org/Projects/TheWatch/
Association of Space Explorers: https://webmail.hq.af.mil/exchweb/bin/redir.asp?URL=http://www.space-explorers.org/
B612: https://webmail.hq.af.mil/exchweb/bin/redir.asp?URL=http://www.b612foundation.org/press/press.html
ProSpace: https://webmail.hq.af.mil/exchweb/bin/redir.asp?URL=http://www.prospace.org/
Planetary Society: https://webmail.hq.af.mil/exchweb/bin/redir.asp?URL=http://www.planetary.org/programs/projects/apophis_competition/
AIAA: https://webmail.hq.af.mil/exchweb/bin/redir.asp?URL=http://www.aero.org/conferences/planetarydefense/ & position paper: https://webmail.hq.af.mil/exchweb/bin/redir.asp?URL=http://www.planetarydefense.info/resources/pdf/Asteroids-Final.pdf
Gaia Shield Group: https://webmail.hq.af.mil/exchweb/bin/redir.asp?URL=http://gaiashield.com/two.html
Lifeboat Foundation: https://webmail.hq.af.mil/exchweb/bin/redir.asp?URL=http://www.lifeboat.com/ex/asteroid.shield
Secure World: https://webmail.hq.af.mil/exchweb/bin/redir.asp?URL=
National Space Society: https://webmail.hq.af.mil/exchweb/bin/redir.asp?URL=http://www.nss.org/settlement/asteroids/
Marsdrive: https://webmail.hq.af.mil/exchweb/bin/redir.asp?URL=http://marsdrive.com/news/asteroid-to-hit-mars.html

Which reminds me, the Canadians have a project called NEOSat, which will spend half its time doing Space Situational Awarness, and the other half doing search for Asteroids. It will use a 15cm diameter telescope. It is about the size of suitcase, and weighs 65kg. They hope to launch it in 2010. Unfortunately, it still apparently needs to find an opportune ride to orbit...perhaps on a polar weather satellite.

The Europeans are also doing interesting work. They are pushing the asteroids onto the agenda for SSA. Currently they still have Don Quiote mission on the books, and one can hope against their troubles that they will not completely abandon it. Particularly in Britain, leading Study Group 14 for the UN COPUOS, and Dr. M. Vasile who is comparing a number of different methods continues to turn out useful work comparing various options.
Another interesting site that will get quite a bit more press early next year is the international Association of Space Explorers (ASE), theinternational organization of astronauts and cosmonauts from 33 countries:
Not in particular this paper, which says:
- Within 10-15 will be tracking~300,000 NEOS =>45m (Tunguska Size) due to projected upgrades, of which 10,000 will have non-zero probability of earth impact in next 100 years and 50-100(.5-1%) are likely to appear threatening enough to warrant active monitoring or deflection!

Back in the US, the official site for the Iowa State Asteroid Deflection Center (ADRC), where eventually the presentations will be posted.

In fact, here is the layout for near term events:
- Dec 2008 - Dedicated National Space Society (NSS) Ad Astra magazine
- Spring 2009, Association of Space Explorers (ASE) issues its report, "Asteroid Threats: A Call for Global Response" to the United Nation's Committee on the Peaceful Uses of Outer Space
- March 23-27 Lunar & Planetary Science Conference
- April 23-24 Space Law Conference: Near Earth Objects (NEOs): Risks and Opportunities, Lincoln, Nebraska
- April 27-30 International Planetary Defense Conference, Grenada, Spain
- October 2010 National Research deadline of review of NASA NEO report to congress
- October 2010 The deadline for the Office of Science and Technology Policy (OSTP) to recommend a lead agency to Congress

24 October 2008

Iowa State Hosts Asteroid Deflection Research Symposium

Iowa State visionary Dr. Bong Wie (supported by Dr. Tom Shih) brought a number of significant agencies from across the US Government and who had expertise or organizational equities in Planetary Defense together with world-class researchers to discuss how to tacke the problem of Asteroid Deflection. The group has jokingly been called the planetary defense volunteers, as at present, no organization has been directly assigned responsibility.

The conference included participants from NASA, DTRA, USAF, AFRL, DHS, DIA, LLNL, Sandia, and NSF as well as the National Academies National Research Council which is now conducting a review of NEO discovery and deflection for the Congress. It also included represenatives from several corporations such as Lockheed, Orbital Sciences, Emergent Space, as well as a number of representatives from SIGMA, a unique think tank (http://www.sigmaforum.org/) which provides pro-bono services to government agencies. Correspondents from the Discovery Channel and National Geographic were also present.

Lindley Johnson provided an excellent overview of history and current NASA efforts, and details of 2008 TC3 incident.

Mark Boslough of Sandia provided compelling computer simulations of Low Altitude Airbursts that he asserted dominated the near threat, and he also made the case that deflection of asteroids for Geoengineering (to Earth-Sun L1 then create dust to create shadow) to avert rapid climate change was even more compelling for him in the near term. He discussed some fascinating and counterintuitive physics of Airburst phenomena that require much lower mass to cause equivalent damage, can create cratering, peristent vortices at temperatures above the melting temperature of rock, and a sort of massive plume where the colder, thicker atmosphere acts as a kind of rocket nozzle for the heated air.

Topics discussed ranged from solar sails, to kinetic impactors, to gravity tugs, to antimatter, fission, and fusion devices, and both deflection and disruption was discussed. The group seemed to think that there was no one best way, but that it would be useful to have a number of tools in the tool kit, but that there was much work to be done to create the underlying tools and common scenarios to allow decisionmakers to make proper selection.

While the conference was mainly technical, a significant theme, perhaps best articlated by Dr. Pete Worden, NASA Ames director, is the near term problem is not so much technology as Command and Control (C2)...who identifies the threat, who validates/believes it, who builds it, who decides, who tests, who tells whom, etc. Links to in-situ resource utilization, space industrialization, prizes and private sector participation (Tom Matula's asteroid bounty idea, Public-Private protected IP/limited liability) were discussed. International aspects were discussed.

Near-term missions for survey (such as NASA Ames MAAT) were discussed, but it was apparent that the existing vehicles for funding such missions currently have criteria to select for the best science or exploration technology, and that critical planetary technology missions are unfortunately not compelling under these criteria.

A spirited discussion took place around the topic of whether or not the discovery program had actually reduced risk, and the role of fear and rationality in decisionmaking. For an excellent discussion of these issues, see the following essay:

18 October 2008

Asteroid Deflection Seminar to Happen in DC

A formal announcement of the ADRS 2008 can be found at

Ames, Iowa—The Iowa State University Asteroid Deflection Research Center (ADRC) is sponsoring an Asteroid Deflection Research Symposium on October 23–24, 2008, at Doubletree Hotel Crystal City-National Airport, Arlington, Virginia. The purpose of this symposium is to exchange technical information and to develop an integrated multidisciplinary R&D program for asteroid deflection/fragmentation using high-energy as well as low-energy options, according to Bong Wie, the Vance D. Coffman Chair Professor in Aerospace Engineering at Iowa State and ADRC director. Planetary defense researchers from such agencies as NASA, the U.S. Air Force, the Air Force Research Laboratory, the Defense Threat Reduction Agency, Sandia National Laboratories, Lawrence Livermore National Laboratory, and the National Research Council as well as industry and academia, plan to participate in the symposium. These are researchers who are currently involved in exploring and/or developing various options for asteroid deflection/fragmentation. The ADRC was established at Iowa State last spring to coordinate and lead a research effort to address the complex engineering and science issues of asteroid deflection. The collision of a moderately large asteroid or comet (also referred to as a near-Earth object) with Earth would have catastrophic consequences. Such events, Wie points out, have occurred in the past and will likely occur again in the future. “For the first time in history,” he adds, “we have practically viable options to counter this threat, but there is no consensus on how to reliably deflect asteroids in a timely manner. This research symposium is a first step in bringing researchers together to discuss options and develop a roadmap for determining the best solution.”

See Brochure at: http://www.adrc.iastate.edu/fileadmin/www.aere.iastate.edu/ADRC/ADRS_2008.pdf

NASA SpaceGuard Shacks Asteroid Strike Prediction

In an extraordinary dress rehearsal of future events to come, the SpaceGuard Survey, for the first time ever discovered an asteroid before impact, and tracked it to impact. Discovered only 20 hours in advance, within 8 hours and 21 minutes, using only four observations, it accurately predicted the time of impact to less than a minute. The asteroid, 2008 TC3, a 5 meter charbonacious chondrite, created an atmospheric detonation (bolide) of 1.1 to 2.1 kilotons over a remote region in Sudan.
Serendipidy played an important role, as a week later, the survey would have been looking at a different section of sky.
The event set off a flurry of notifications through US and international agencies. Such notifications are important not only in the case that a larger impact could cause casualties, but even a smaller impact such as this one might be mistaken in some tense regions as a nuclear test or strike.

7 10 2008 Posted by Dee Norris
A recently discovered Apollo Asteroid, 2008 TC3, exploded over Sudan at about 1046 EDT on October 7, 2008. 2008 TC3 was discovered on Monday by an observer at the Mt Lemmon Observatory near Tucson, Arizona. 2008 TC3 is notable in that it is the first Asteroid of its size that was identified before impact and tracking it put the entire Spaceguard tracking system to an extreme test. TC3 is estimated to be only two to five meters in diameter but exploded with the force of a one kiloton nuclear device. Asteroids of this size hit the Earth every few months according JPL scientists. No deaths have been reported yet. The important lesson here is that Spaceguard is able to identify and track these smaller objects as well as the larger ones. A 20 to 50 meter asteroid exploding over a major city could result in a significant loss of property and life. The most imagined dire consequences of AGW could never stack up to the actual consequences of a larger asteroid actually impacting nearly anywhere on the Earth. If for this reason alone, funding for space exploration needs to be continued.
2008 TC3 (Catalina Sky Survey temporary designation 8TA9D69) was a meteoroid 2 to 5 meters (7 to 16 ft) in diameter that entered Earth's atmosphere on October 7, 2008, at 02:46 UTC (5:46 a.m. local time) and burned up before it reached the ground.
The meteoroid was discovered by an observer at the Catalina Sky Survey (CSS) 1.5 meter telescope at Mount Lemmon, north of Tucson, Arizona, USA, about a day before the impact.[2][3] The meteoroid was notable as the first such body to be observed and tracked prior to reaching Earth.[4] The process of detecting and tracking a near-Earth object, an effort sometimes referred to as Spaceguard, was put to a test. In total, 586 astrometric and almost as many photometric observations were performed by 27 amateur and professional observers in less than 19 hours and reported to the Minor Planet Center, which issued 25 Minor Planet Electronic Circulars with new orbit solutions in eleven hours as observations poured in. Impact predictions were performed by University of Pisa's CLOMON 2 semi-automatic monitoring system[5][6] as well as Jet Propulsion Laboratory's Sentry system. Spectral observations that were performed by astronomers at the 4.2 meter William Herschel Telescope at La Palma, Canary Islands are consistent with either a C-type or M-type asteroid. The meteoroid, also considered a bolide[7] due to its fiery explosion, is confirmed to have entered Earth's atmosphere above northern Sudan at a velocity of 12.8 kilometres per second (8.0 mi/s). Estimated trajectory has the object coming out of the western sky at an azimuth of 281 degrees, and an altitude angle of 19 degrees to the local horizon.

Meteosat 8 / EUMETSAT IR image of the 2008 TC3 explosion. Copyright 2008 EUMETSAT
It exploded tens of kilometers above the ground with the energy of around one kiloton of TNT, causing a large fireball in the early morning sky.[8] Very few people inhabit the remote area of the Nubian Desert where the explosion took place; The Times, however, reported that the meteoroid's "light was so intense that it lit up the sky like a full moon and an airliner 1,400 km (870 miles) away reported seeing the bright flash."[9] A low-resolution image of the explosion was captured by the weather satellite Meteosat 8.[10] The Meteosat images place the fireball at 21°00′N 32°09′E / 21.00, 32.15.[11] Infrasound detector arrays in Kenya also detected a sound wave from the direction of the expected impact corresponding to energy of 1.1 to 2.1 kilotons of TNT.[12] Meteoroids of this size hit Earth about two or three times a year.[13]
The trajectory showed intersection with Earth's surface at roughly 20°18′N 33°30′E / 20.3, 33.5[14] though the object was expected to break up perhaps 100–200 kilometers west as it descended, somewhat east of the Nile River, and about 100 kilometers south of the Egypt–Sudan border.
According to U.S. government sources[15][16] U.S. satellites detected the impact at 02:45:40 UT, with the initial detection at 20°54′N 31°24′E / 20.9, 31.4 at 65.4 km altitude and final explosion at 20°48′N 32°12′E / 20.8, 32.2 at 37 km altitude.
Don YeomansNASA/JPL Near-Earth Object Program OfficeOctober 6, 2008
A very small, few-meter sized asteroid, designated 2008 TC3, was found Monday morning by the Catalina Sky Survey from their observatory near Tucson Arizona. Preliminary orbital computations by the Minor Planet Center suggested an atmospheric entry of this object within a day of discovery. JPL confirmed that an atmospheric impact will very likely occur during early morning twilight over northern Sudan, north-eastern Africa, at 2:46 UT Tuesday morning. The fireball, which could be brilliant, will travel west to east (from azimuth = 281 degrees) at a relative atmospheric impact velocity of 12.8 km/s and arrive at a very low angle (19 degrees) to the local horizon. It is very unlikely that any sizable fragments will survive passage through the Earth's atmosphere. Objects of this size would be expected to enter the Earth's atmosphere every few months on average but this is the first time such an event has been predicted ahead of time.
Update - 6:45 PM PDT (1 hour prior to atmospheric entry)
Since its discovery barely a day ago, 2008 TC3 has been observed extensively by astronomers around the world, and as a result, our orbit predictions have become very precise. We estimate that this object will enter the Earth's atmosphere at around 2:45:28 UTC and reach maximum deceleration at around 2:45:54 UTC. These times are uncertain by +/- 15 seconds or so. The time at which any fragments might reach the ground depends a great deal on the physical properties of the object, but should be around 2:46:20 UTC +/- 40 seconds.

Okay, so Asteroid 2008 TC3 wasn’t an Earth-killer, but rather a crowd-thriller. It wasn’t miles across-not even tens of meters across. It was, perhaps, a few meters in size, similar in volume to mid-size car. In fact, it didn’t even hit the Earth’s surface, but vaporized in the atmosphere.
Sounds a bit anticlimactic-and that’s not the half of it. It’s not even a rare event! Objects of this size are believed (and sometimes observed) to enter Earth’s atmosphere a few times each year. So what’s the blog deal? Observers on the ground reported the fireball lit up the skies with the intensity of the Full Moon. A nearby airliner (not in danger, as the fireball exploded tens of kilometers above the ground, well above the airliner’s flight path) reported seeing a bright flash.
In a sense, this event was kind of a dress rehearsal for the international system of predicting, and possibly defending against, impacts on Earth by much larger asteroids and comets. We already know of thousands of Near Earth Objects (NEOs-asteroids and comets that cross Earth’s orbit and are large enough to cause a catastrophe should they strike the Earth). It is also expected that there are many thousands more that we haven’t yet detected, being small enough to “fly under the radar” of our NEO detecting network.
Early detection and sustained tracking of NEOs is key to the protection plan against impact disaster. If we can accurately predict an impact far enough in advance, we could potentially send a spacecraft to it and gently “nudge” it off course and deflect the eventual impact.
So ends the existence of another chunk of rock that had, up to that point, been serenely orbiting the Sun for billions of years…

An asteroid with a size of a few meters in diameter hit the Earth a few hours ago. The news is reported by the Central Bureau for Astronomical Telegrams, circular 8990. Below is the expected trajectory of the body. The small asteroid was discovered yesterday at Mt. Lemmon by R.A.Kowalski, as an object with a visual magnitude of about 30.4. The object was then at about 450,000 kilometers from our planet. Those who were able to look up this night might have spotted it before it entered our atmosphere only with a telescope, since its expected magnitude was probably around 11. A bright fireball might have been observed over northern Africa, and a possible fall might have resulted, depending on the composition of the rock.
More information is available at the CBAT site.
UPDATE: the body was 5 meters in diameter. It was a carbonaceous chondrite, and its darkness explains why the diameter had been underestimated by luminosity measurements before the impact. It is quite likely that many small bodies will be found in northern Sudan, which is above the impact point of the asteroid. Also worth noting is that dr. Peter Brown, from West Ontario University, detected a sound wave from the impact with detectors located in Kenya.
The fireball made by the body at 4.46AM yesterday has been spotted by a airplane pilot from Air France-KLM, according to Jacob Kuiper, a meteorologist from the Netherlands who had informed the pilots of the possibility before the impact. The fall has freed an energy of about two kilotons of TNT, about a tenth of the energy of the first atomic bomb over Hiroshima.
UPDATE: thanks to the Meteosat, we now have a picture of the event. It is a temperature scan, which shows the impact of the object with the atmosphere. It is the first time that the impact of a body with the Earth is predicted and then observed. Near-Earth object surveys are getting better and better…
By Emily Lakdawalla
Oct. 7, 2008 16:15 PDT 23:15 UTC
Over the last 24 hours it has been tiring but really fun to watch the drama of asteroid 2008 TC3. It has happened so quickly that it's necessary to convert all times to UTC in order to see how events have unfolded across the globe. Fortunately for my sanity, nearly all of the events are neatly collected on the Minor Planets Mailing List. To briefly review: the night before last (my time), or at 06:38 UTC on October 6, astronomers at the University of Arizona discovered an object provisionally called 8TA9D69 that appeared to be on a collision course with Earth. Three other observatories reported sightings within the next few hours -- Sabino Canyon and Siding Spring in Arizona and a Royal Astronomical Society site in Moorook, Australia. Together these four observers provided enough data on the object so that a Minor Planet Electronic Circular was issued at 14:59 UTC the same day, giving 8TA9D69 the more formal name 2008 TC3, and advising the astronomical community that "The nominal orbit given above has 2008 TC3 coming to within one earth radius around Oct. 7.1. The absolute magnitude indicates that the object will not survive passage through the atmosphere. Steve Chesley (JPL) reports that atmospheric entry will occur on 2008 Oct 07 0246 UTC over northern Sudan."
The object wouldn't be more than a big meteor, but even so, it represented the first time ever that an object had been observed before it was to hit Earth, and, clearly, astronomers around the world scrambled to their telescopes to observe it before it was to pass into Earth's shadow (and, therefore, invisibility) just before 01:50 UTC. The observations were partly for the thrill -- seeing an object in its last hours, before it met a fiery fate in Earth's atmosphere -- but they also had a more important purpose: to refine the orbit of the object, which would, in turn, improve the predictions of where it would hit. Over the next 11 hours, fully 24 Minor Planet Electronic Circulars were issued with further observations, pinning down 2008 TC3's final path with high precision. One terrific set of images, from Eric Allen, is shown at right. Like many of the amateur astronomers participating in the impromptu 2008 TC3 observing campaign, Allen's work has been aided by Planetary Society members, through the Gene Shoemaker Near Earth Object Grant Program. With the object so close to Earth, the parallax of different observers on different parts of the globe allowed much greater precision than is usual, given the short observing arc. The initial impact prediction was confirmed by JPL scientist Paul Chodas at 01:45 UTC: "We estimate that this object will enter the Earth's atmosphere at around 2:45:28 UTC and reach maximum deceleration around 2:45:54 UTC at an altitude of about 14 km. These times are uncertain by +/- 15 seconds or so." After positional information, the next challenge was to obtain spectral data -- information on the color of the object, which would help to classify it and determine its origin. The first I heard of such data being captured successfully was from this item on the MPML by Alan Fitzsimmons and coworkers at Armagh Observatory: "We obtained optical spectra of 2008 TC3 using the 4.2m William Herschel Telescope and ISIS spectrograph on Oct 6.93-6.94UT. The spectra cover the range 546-995nm at a resolution of 4nm. Initial analysis of the spectra via comparison with the solar analogue 16CygB reveals a featureless reflectance spectrum with no indication of the silicate absorption feature longward of 800nm." Presumably there were other observers who were able to obtain spectral data, though not as many as were gathering positional information. Time quickly ran out to observe the asteroid, however. Astronomers in Spain recorded 2008 TC3's entry into Earth's shadow, hiding it from view for its final hour of descent. The image is below:
2008 TC3 disappears into Earth's shadow, on its way to impactTraveling from right to left in this image, asteroid 2008 TC3 entered first the umbra (at 1:47:30 UTC) and then the penumbra (at 1:49:50) of Earth, disappearing into shadow for the final hour of its approach to burning up in the atmosphere over Sudan. The view is a six-minute exposure tracked at sidereal rate (so stars stay fixed). Exposure start time was October 7, 2008, at 01:45:23 UTC. The view is half a degree wide, comparable to the size of the full Moon. At the start of the exposure 2008 TC3 was at a distance of 29,600 kilometers, approaching at a speed of 7.61 kilometers per second. The periodic light variation along the early part of the trail indicates a fast rotation of the intruder around its spin axis. Credit: La Sagra Sky Survey, Spain The atmospheric entry occurred over an extremely remote location on Earth, just 20 hours after it was first discovered. As yet there are no confirmed images of the fireball -- it's possible there may never be any. There is one possible sighting: one resourceful enthusiast, Jacob Kuiper, the General Aviation meteorologist at the National Weather Service in the Netherlands, called an official of the Air-France-KLM airline at the Amsterdam airport to inform him "about the possibility that crews of their airliners in the vicinity of impact would have a chance to see a fireball. And it was a success! I have received confirmation that a KLM airliner, roughly 750 nautical miles southwest of the predicted atmospheric impact position, has observed a short flash just before the expected impact time 0246 UTC. Because of the distance it was not a very large phenomenon, but still a confirmation that some bright meteor has been seen in the predicted direction." (This via spaceweather.com.) And there's more than one way to detect an asteroid impact. Even in relatively unpopulated areas, there are seismological stations scattered around the world, using infrasound to record seismic events. One such station seems to have detected a 1 to 2-kiloton blast associated with the impact. This is according to Peter Brown, of the University of Western Ontario [hey, that's the same university that's home to asteroid mapping genius Phil Stooke]. Brown said:
A very preliminary examination of several infrasound stations proximal to the predicted impact point for the NEO 2008 TC3 has yielded one definite airwave detection from the impact. The airwave was detected at the Kenyian Infrasonic Array, (IMS station IS32), beginning near 05:10 UT on Oct 7, 2008 and lasting for several minutes. The signal correlation was highest at very low frequencies – the dominant period of the waveform was 5-6 seconds. The backazimuth of the signal over the entire 7 element array is shown in the attached map – it clearly points to within a few degrees of the expected arrival direction. Moreover, assuming a stratospheric mean signal speed of 0 28 km/s, the arrival time corresponds to an origin time near 02:43 UT, which is consistent with the expected impact time near 02:45:40 UT given expected variations in stratospheric arrival speeds. The dominant period of 5-6 seconds corresponds to an estimated energy (using the AFTAC period at maximum amplitude relationship from ReVelle, 1997) of 1.1 – 2.1 kilotons of TNT. The five other closest infrasound stations were briefly examined for obvious signals and showed none – more detailed signal processing of these additional data are ongoing in the search for additional signals.
Detection of the 2008 TC3 impact by infrasoundAn infrasound station (intended for the detection of seismic events) in Kenya recorded the blast associated with the atmospheric entry of asteroid 2008 TC3 over Sudan. Credit: Peter Brown, University of Western Ontario All in all, I think the episode of 2008 TC3 has proven that the world's astronomical community, at least, is prepared to respond when an object on a collision course is detected. Within just a few hours of its discovery, the digitally connected world knew exactly where and when the object would hit, and also that it posed no threat. It was a wonderful simulation of the first part of the call to arms when a truly threatening object is detected. But of course we now have to ask ourselves: what would have happened if the object was much bigger than 2 meters in diameter? Reassuringly, the first thing that would have happened is that the detection most likely would have happened much earlier. The bigger and more hazardous an object is, the brighter it is, and the sooner we will detect it. We will likely have way more than 20 hours' warning of an incoming dangerous object. Still, though, the warning time for a tens-of-meter-diameter object could only be measured in days. If we'd had three days' warning of a dangerous impactor heading for Sudan, what could the world have done? The remote location of the impact would have been fortunate for humanity in general, but disastrous for the few people who lived out in that remoteness. Could the developed world have done anything to prevent yet another humanitarian disaster from befalling the Sudanese? The Planetary Society is seeking answers to these questions. We have joined the Association of Space Explorers and the B612 Foundation in their efforts to develop an international framework for planetary defense, and we plan to hold both an invited workshop and a public meeting on these issues in the summer of 2009, as a part of the International Year of Astronomy. When the time is right, we will push for action on this issue from the United Nations' Committee on the Peaceful Uses of Outer Space. A final plea to wrap up this story: if you'd like to support these efforts to protect our planet from hazards from space, please vote with your wallet by sending a donation our way. Any amount is helpful!

20 August 2008

Russian expert says nuclear devices can defend against asteroids

Russian expert says nuclear devices can defend against asteroids
RIA Novosti
01/07/2008 18:45
MOSCOW, July 1 (RIA Novosti) - Nuclear explosive devices are the most effective means of protecting Earth from possible collisions with space bodies, including comets and asteroids, a Russian nuclear physicist told RIA Novosti on Tuesday.
Scientists around the world have long been seeking means of protecting the Earth from the threat of dangerous Near Earth Objects (NEOs). Scientists say such collisions pose a threat on average once every 200-1,000 years.
Vadim Simonenko, deputy head of the Russian Federal Nuclear Center, believes that nuclear explosive devices are more energy efficient, compact and less heavy than lasers or the so-called "gravitational tractors" in terms of their practical application as "weapons against NEOs."
"We in Russia have a wealth of experience in the controlled use of nuclear explosions for peaceful purposes," Simonenko said. "A nuclear device in skillful hands is like a scalpel in the hands of a surgeon."
The scientist said special nuclear devices must be created for effective use against NEOs. In order to disperse an asteroid with diameter of up to 100 meters, these devices must have a yield of about one megaton of TNT equivalent, and weigh several hundred kilograms.
"It is a difficult technical task but it can be accomplished. Besides, there is no need for actual testing [of these devices] because it may be done through computer modeling," he said.
Existing nuclear devices, both military and civilian, were created for specific purposes and do not meet the requirements for "precision strikes" against NEOs, especially comets, which are less predictable than asteroids, Simonenko said.
An earlier report at a Moscow scientific conference said 99942 Apophis, or Asteroid 2004 MN4, with a diameter of 350 meters, currently poses biggest space threat to Earth.
In 2029, this NEO will be at a distance of only 36,000 km (22,400 miles) - closer than satellites in geostationary orbit. Earth's gravity could alter the path of Apophis in such a way that it would collide with Earth on its next approach in 2036.
The explosion could surpass the famous Tunguska explosion of June 30, 1908, which affected a 2,150 square kilometer (830 sq miles) area of Russia felling over 80 million trees in the Krasnoyarsk Territory in Siberia.
Some researchers believe, however, that blowing up NEOs in space poses could result in large fragments surviving the fiery passage through the atmosphere and still hitting the planet.
They propose a more cautionary approach toward dealing with NEOs, by deflecting them from their collision path toward the Earth.
"Deflection is the most favorable strategy, but it requires a considerable early warning period - up to a few years," Simonenko said. "We may not have such a luxury because small asteroids [100-150 m in diameter] are hard to detect."

Following are reports on the status of the Russian efforts toward planetary defense. The information has been communicated by Vadim Simonenko and Anatoly Zaitsev of the Russian Federal Nuclear Center at Snezhinsk (Chelyabinsk-70). It is primarily the results of three meetings of the Space Protection of the Earth conference.