Showing posts with label Air Force. Show all posts
Showing posts with label Air Force. Show all posts
10 September 2012
03 March 2012
Space Solar Power Article in Strategic Studies Quarterly (SSQ)
http://www.au.af.mil/au/ssq/2012/spring/garretson.pdf
Here is just the opening:
Space-based solar power (SBSP) is a concept for a revolutionary energy system. It involves placing into orbit stupendously large orbital power plants—kilometers across—which collect the sun’s raw energy and beam it down to where it is needed on the earth. In theory, SBSP could scale to meet all of humanity’s energy needs, providing virtually unlimited green, renewable power to an energy-hungry world.
Most renewable energy schemes sufer from intermittency and low energy density, requiring vast amounts of land and extensive storage as well as fossil fuel backup systems. Not so with SBSP systems. When placed in orbit where the sun shines constantly, they can deliver stable, uninterrupted, 24-hour, large-scale power to the urban centers where the majority of humanity lives. A network of thousands of solar-power satellites (SPS) could provide all the power required for an Earth-based population as large as 10 billion people, even for a fully developed “irst world” lifestyle but without the environmental downsides of nuclear or coal.
Should space-based solar power have a role in the US grand strategy for space? Should Airmen advocate for a US program in SBSP? Depending on your viewpoint, SBSP is either the most important space project of our generation—critical to securing American long-term interests and requiring the advocacy of Airmen—or a fool’s errand, an impossible dream threatening to divert valuable resources from where they are most needed today
Here is just the opening:
Solar Power in Space?
Peter Garretson, Lieutenant Colonel, USAF
Whoever takes the lead in the development and utilization of clean
and renewable energy and the space and aviation industry will be
the world leader.
—Prof. Wang Xiji, Chinese space program pioneer
Most renewable energy schemes sufer from intermittency and low energy density, requiring vast amounts of land and extensive storage as well as fossil fuel backup systems. Not so with SBSP systems. When placed in orbit where the sun shines constantly, they can deliver stable, uninterrupted, 24-hour, large-scale power to the urban centers where the majority of humanity lives. A network of thousands of solar-power satellites (SPS) could provide all the power required for an Earth-based population as large as 10 billion people, even for a fully developed “irst world” lifestyle but without the environmental downsides of nuclear or coal.
Should space-based solar power have a role in the US grand strategy for space? Should Airmen advocate for a US program in SBSP? Depending on your viewpoint, SBSP is either the most important space project of our generation—critical to securing American long-term interests and requiring the advocacy of Airmen—or a fool’s errand, an impossible dream threatening to divert valuable resources from where they are most needed today
16 September 2010
Why Not Space Solar Power?
Spacenews has published an OpEd by Don Flournoy on Space Solar Power
Why Not Space Solar Power?
Mon, 13 September, 2010
By Don Flournoy
The 2010 U.S. National Space Policy, which supports a robust and competitive commercial space sector, is good news for those of us working to design and launch the new types of satellites that will collect solar energy in space and deliver it to Earth as a nonpolluting source of electrical power.
Among the goals of President Barack Obama’s National Space Policy is expansion of international cooperation on mutually beneficial space activities to “broaden and extend the benefits of space” and “further the peaceful use of space.”
As members of the National Space Society, the Society of Satellite Professionals International and the Space Energy Group, we believe space, as a shared resource, can best be explored and developed by a partnership of nations and businesses working together.
Since acquiring clean and abundant energy is a common requirement for economic growth and an eventual necessity for the health of all societies, harvesting space solar power is a logical human endeavor when the high frontier is precisely where energy is most plentiful. But achieving success doing large-scale commercial innovation in outer space requires long-range planning, pooling of financial resources, sharing of knowledge and expertise, and the careful framing of a way forward that will earn and sustain the public trust.
In naming the CEOs who will serve on his new advisory board on trade issues, Obama noted in July that the U.S. is on track to double exports in the next five years, and he pointed to some of the ways the American economy is being repositioned to better compete abroad. When adding that announcement to the outcomes of the June summit of the Group of 20 major industrial countries in Canada and recent federal policy statements intimating that (certain) export controls will be relaxed and cooperation in space will be encouraged, it would appear that the U.S. could be entering a new era of openness for international business.
To this end, we would like to see some greater leadership and support given to space solar power development by NASA and the U.S. departments of Energy and Commerce. A helpful first step would be a U.S.-led space solar power feasibility study to which all interested nations are invited to contribute.
In the context of the U.S. National Space Policy, such a feasibility study could lead the way in assessing and promoting “appropriate cost and risk sharing among participating nations in international partnerships.” It would demonstrate U.S. “tangible leadership in space,” leveraging the capabilities of allies while assuring continuing adherence to the U.N. Treaty on Exploration and Use of Outer Space — now signed by 125 states, including China and India — that dictates “nuclear weapons and other weapons of mass destruction” shall not be placed in outer space.
At the International Space Development Conference held in Chicago in May, multiple nations participated in a National Space Society-initiated Solar Power Symposium to examine in depth opportunities and challenges for energy generation in near space. Former Indian President A.P.J. Abdul Kalam, scientist, aeronautical engineer and proponent of space solar power, addressing the symposium via videoconference, spoke to the need for international cooperation in space. He proposed a multilateral global initiative that could map out for us what needs to be done to bring space solar power to operational reality.
From our perspective, space solar power is a meaningful science, engineering and commercial challenge that deserves our attention and investment. In the wake of the Gulf of Mexico oil disaster, we think it is time for the U.S. to put space solar power on our national energy agenda. At the same time, we must seek opportunities to learn from and participate with Canada, China, India, Japan, the European Union and others taking their first tentative steps to bring space solar energy to Earth.
In a June Times of India commentary on strategic international diplomacy, U.S. Sen. John Kerry expressed support for a partnership with India that would include “the quest for new technologies and fresh ideas for economically viable ways to speed the shift to renewable energy sources.”
We believe that within the mainstream of global science, engineering and environmental management there are game-changing ideas and technologies that await testing. It is time to see some space solar power demonstration projects. Of all the possible alternative energy sources on the near horizon, we believe space solar power is our best chance for addressing the worldwide challenges of climate change, renewable energy and continued economic growth.
__________
Don Flournoy is a professor and editor of the Online Journal of Space Communication (www.spacejournal.org) at Ohio University. This article also reflects the opinions of Robert Bell of the Society of Satellite Professionals International, Mark Hopkins of the National Space Society, Stephan Tennsel of Space Energy AG, and Feng Hsu of the Space Energy Group.
More news and blog entries on the Indo-US SBSP proposal:
India-US space-based solar power plan could solve major energy issues - study
(ADPnews) - Sep 14, 2010 - A space-based solar power (SBSP) programme developed by India and the US could solve the energy security and climate change issues, according to a report by US Air Force lieutenant colonel Peter Garretson.
Garretson, who is on a sabbatical as an international fellow at the institute for defence studies and analyses in New Delhi, considers that the two countries should conduct a feasibility analysis on such a programme, whose aim will be to replace fossil fuel energy with SBSP by 2025. However, in order to work on such a plan, India should first sign the Missile Technology Control Regime (MTCR) document, which the country declined to do earlier, deeming it discriminatory.
In his report, Garretson has included a three-phase plan, which starts with an initial five-year programme costing USD 10 million to USD 30 million for the development of contributing technologies and competent workforce. It is followed by a USD-10-billion investment in the construction of a sub-scale space solar power system over a 10-year period. The concluding stage envisages the establishment of an Indian-US consortium to face energy security and carbon mitigation issues.
Such a SBSP programme could be managed by the US Department of State's Office of Ocean Environment and Science and the Prime Minister's Council on Climate Change in India, according to Garretson's report.
Making the Case An Indo-USA Space-Based Solar Power Programme
By Bill Moore
I had a rude awakening this evening. What began as a casual journey into India's space programme -- the reasons will be apparent momentarily -- ended with the sobering realization that along with the sub-continent's explosive economic growth and the rise of the middle class, also comes the apparent need to flex its political muscles militarily in the form of nuclear submarines -- the first launched last year with more on order -- tactical transport aircraft jointly developed with the Russians, and even their own armada of aircraft carriers. And then there's their plan to send men to the moon by 2016.
I've been reading Peter Garretson's 2009 research paper for Indian Defense Studies and Analysis entitled, "Sky's No Limit: Space-based Solar Power, The Next Major Step in the Indo-US Strategic Partnership?" It is a heavily footnoted document of some 174 pages and six appendices. In it, Garretson makes the case that the next step in the United States and India's strategic relationship should be establishment of a "big policy" programme (I'll use the British spelling) to put solar power generation systems in earth orbit. While the paper doesn't go into the technological issues, it does focus on the policy implementation barriers of such a collaboration.
Of course, as a parochial American with only a passing knowledge of Indian food -- which I love -- and Bollywood movies -- which I also find highly entertaining as long as I can keep up with the English subtitles -- I asked myself was India, in fact, technologically capable of making a meaningful contribution to such a programme? Sure, their Chandrayaan-1 moon mission was an impressive achievement, discovering evidence for water, but could they really be expected to lift millions of pounds of components into geosynchronous orbit to build hundreds, even thousands of 5 km width solar arrays?
The answer is, in fact, yes. The Indian Space Research Organization (ISRO) has a series of launch vehicles; the largest being the GSLV III, now in development, will be capable of lifting 4,500kg (10,000 lbs) of payload into geosynchronous transfer orbit, putting it on a par with competing American and French launch vehicles. Importantly, it appears they can do it rather cheaply. The Chandrayaan-1 mission in 2008 cost just US$79 million.
And why should India or the United States even consider such an initiative, either alone or in partnership? Besides the fact that the Japanese are spending money on their own SBSP program and plan to have a 1 GW platform in orbit by 2030, you mean? Garretson takes pains to explain that it may, in fact, be the only choice the planet has to provide humanity with the clean, pollution-free, electric power it needs, especially in populous nations like India where 50-60% of it citizens will be living in cities by 2039. At present, India, as well as the United States, depends on coal-fired power plants for half of its electricl power generation capacity. It is estimated India's coal reserves will last 80 years, but Garretson points out that at a projected growth rate of just 5 percent a year, those reserves will be exhausted in 45 years; and this doesn't even address the critical problem of water shortages in India, water on which thermoelectric power plants, both fossil fuel and nuclear, are dependent.
So, why not simply build vast solar farms in India's Thar Desert, which stretches across the northwestern states of Rajasthan and Gujara, and occupies more than 2.5 million square kilometers? Efficiency and intermittency are why. All earth-bound solar installations suffer from the same problem: the sun shines on them only part of the day and the atmosphere -- and its associated weather -- reduce their efficiency even further. Space-based solar stations can provide solar power, transmitted back to earth in the form of low-frequency radio waves, 24 hours a day at the sun's maximum power rate of 1330+ watts per meter. At least that's the theory. Those same radio waves have to penetrate the atmosphere and its weather, be converted by circular farms of specially-designed rectenna's with 80 percent-plus efficiency back to electric power and then distributed to urban centers. In a footnote(14) on page 23 of Garretson's paper, it is estimated that only two percent of the energy transmitted down to earth would be lost in the form of heat, and that the type of radio wave being considered will have no or virtually no impact on humans or animals. He notes that, "NASA, DOE, and EPA have conducted extensive experiments to assess if there were ill effects to biological life or the upper atmosphere due to such beams. None of the studies conducted so far suggest that there is any significant detrimental effect."
Assuming all other objections and technical issues can be resolved, what's the potential of SBSP and what's its cost? Citing studies by James Snead and Harry Stine (footnote 10, page 22) Garretson estimates, "the exploitable energy in orbit exceeds not just the electrical demand of the planet today, but the total energy needs of a fully developed planet with over 10 billion people." As for the question of cost, Sky's No Limit estimates that the world currently spends $6 trillion on energy of all forms annually. Most of that energy produces highly undesirably pollution and climate change, which SBSP would not. Further, SBSP would make no environmental demands on the planet's freshwater supply.
The idea would certainly seem to have merit. Imagine an EV world where all our motor vehicles are powered by electricity transmitted from thousands of orbiting solar stations. However, moving such a project from the dreamer's stage to the schemer's stage will prove the first major obstacle to overcome. If nothing else, Sky's No Limit makes thought-provoking reading. It certainly opened my eyes to the state of technological development taking place in India beyond Tata Nanos, Revas and Hero electric bicycles.
New Space Energy Newsletter:
http://www.spaceenergy.com/AnnouncementRetrieve.aspx?ID=56424
It reviews the IDSA-CFR paper on Indo-US Space Solar Power cooperation.
Introduction of Peter Garretson´s New SBSP Paper: "Sky´s No Limit"
Hot off the press, Space Energy is proud to announce the publication of the latest paper from one of the original SBSP `caballeros´, Peter Garretson, entitled “Sky’s No Limit: Space-Based Solar Power, the Next Major Step in the Indo-US Strategic Partnership?”
Referred to as IDSA Occasional Paper No. 9, this paper provides a policymaker's overview of a highly scalable, revolutionary, renewable energy technology, Space-Based Solar Power (SBSP), and evaluates its utility within the context of the Indo-US strategic partnership. After providing an overview of the concept and its significance to the compelling problems of sustainable growth, economic development, energy security and climate change, it evaluates the utility of the concept in the context of respective Indian and US political and energy-climate trajectories. The paper concludes that a bilateral initiative to develop Space-Based Solar Power is highly consistent with the objectives of the Indo-US strategic partnership, and ultimately recommends an actionable three-tiered programme to realize its potential.
Peter Garretson's credentials are unparalleled. He was a Council on Foreign Relations (CFR), International Fellow in India, and a Visiting Fellow at the Institute for Defence Studies and Analyses (IDSA) in New Delhi. He is an active duty Air Force officer on sabbatical as an Air Force Fellow. He was previously the Chief of Future Science and Technology Exploration for Headquarters Air Force, Directorate of Strategic Plans and Programs, and is a former DARPA Service Chiefs’ Intern, and former Los Alamos National Laboratory (LANL) Service Academy Research Associate. He is a published author on Space Grand Strategy, and is a recipient of the National Space Society’s (NSS) Space Pioneer Award.
Peter Garretson´s past IDSA papers can be found here.
Referred to as IDSA Occasional Paper No. 9, this paper provides a policymaker's overview of a highly scalable, revolutionary, renewable energy technology, Space-Based Solar Power (SBSP), and evaluates its utility within the context of the Indo-US strategic partnership. After providing an overview of the concept and its significance to the compelling problems of sustainable growth, economic development, energy security and climate change, it evaluates the utility of the concept in the context of respective Indian and US political and energy-climate trajectories. The paper concludes that a bilateral initiative to develop Space-Based Solar Power is highly consistent with the objectives of the Indo-US strategic partnership, and ultimately recommends an actionable three-tiered programme to realize its potential.
Peter Garretson's credentials are unparalleled. He was a Council on Foreign Relations (CFR), International Fellow in India, and a Visiting Fellow at the Institute for Defence Studies and Analyses (IDSA) in New Delhi. He is an active duty Air Force officer on sabbatical as an Air Force Fellow. He was previously the Chief of Future Science and Technology Exploration for Headquarters Air Force, Directorate of Strategic Plans and Programs, and is a former DARPA Service Chiefs’ Intern, and former Los Alamos National Laboratory (LANL) Service Academy Research Associate. He is a published author on Space Grand Strategy, and is a recipient of the National Space Society’s (NSS) Space Pioneer Award.
Peter Garretson´s past IDSA papers can be found here.
A presentation made by the author of the IDSA-CFR Report can be downloaded from here:
26 September 2009
Asteroid attack: Putting Earth's defences to the test
From: http://www.newscientist.com/article/mg20327271.300-asteroid-attack-putting-earths-defences-to-the-test.html
(See the outstanding video)
http://www.newscientist.com/articlevideo/mg20327271.300/41841503001-asteroid-attack-putting-earths-defences-to-the-test.html
IT LOOKS inconsequential enough, the faint little spot moving leisurely across the sky. The mountain-top telescope that just detected it is taking it very seriously, though. It is an asteroid, one never seen before. Rapid-survey telescopes discover thousands of asteroids every year, but there's something very particular about this one. The telescope's software decides to wake several human astronomers with a text message they hoped they would never receive. The asteroid is on a collision course with Earth. It is the size of a skyscraper and it's big enough to raze a city to the ground. Oh, and it will be here in three days.
Far-fetched it might seem, but this scenario is all too plausible. Certainly it is realistic enough that the US air force recently brought together scientists, military officers and emergency-response officials for the first time to assess the nation's ability to cope, should it come to pass.
They were asked to imagine how their respective organisations would respond to a mythical asteroid called Innoculatus striking the Earth after just three days' warning. The asteroid consisted of two parts: a pile of rubble 270 metres across which was destined to splash down in the Atlantic Ocean off the west coast of Africa, and a 50-metre-wide rock heading, in true Hollywood style, directly for Washington DC.
The exercise, which took place in December 2008, exposed the chilling dangers asteroids pose. Not only is there no plan for what to do when an asteroid hits, but our early-warning systems - which could make the difference between life and death - are woefully inadequate. The meeting provided just the wake-up call organiser Peter Garreston had hoped to create. He has long been concerned about the threat of an impact. "As a taxpayer, I would appreciate my air force taking a look at something that would be certainly as bad as nuclear terrorism in a city, and potentially a civilisation-ending event," he says.
The latest space rock to put the frighteners on us was 2008 TC3. This car-sized object exploded in the atmosphere over Sudan in October last year. A telescope first spotted it just 20 hours before impact - at a distance of 500,000 kilometres - and astronomers say we were lucky to get any warning at all.
Thankfully, 2008 TC3 was far too small to do any damage on the ground, but we are nearly as blind to objects big enough to do serious harm. We have barely begun to track down the millions of skyscraper-sized asteroids zipping around Earth's neighbourhood, any one of which could unleash as much destructive power as a nuclear bomb on impact.
Asteroid impacts are not as rare as you might think. It is widely accepted that an asteroid or comet 30 to 50 metres across exploded over Tunguska in Siberia in 1908, flattening trees for dozens of kilometres all around. The chance of a similar impact is about 1 in 500 each year (Nature, vol 453, p 1178). Put another way, that's a 10 per cent chance of an impact in the next 50 years (see "Should we panic?").
"Fifty-metre asteroids scare me to death," says Timothy Spahr, director of the Minor Planet Center in Cambridge, Massachusetts. "I could easily see a 50-metre object hitting in three days causing absolute pandemonium."
During the US air force planning exercise, the participating scientists explained that with so little warning there would be no hope of preventing an impact. Even Innoculatus's smaller 50-metre asteroid would weigh hundreds of thousands of tonnes, requiring an enormous push to change its trajectory appreciably - so much so that detonating a nuke near it in space would not provide a sufficient impulse so late in the game to cause a miss. To deflect an asteroid sufficiently, force would need to be applied years in advance (see "Could we nuke it?").
In fact, it could make things worse by breaking the asteroid into pieces, some of which could be large enough to do damage, and even create a blizzard of meteors that would destroy satellites in Earth orbit.
Panic on the streets
Realistically, though, the nuclear option would not be on the table in the first place: the nuclear-tipped missiles sitting patiently in silos around the world are not designed to track and home in on an asteroid or even survive for more than a few minutes in space. Instead, we would simply have to brace ourselves for the impact.
The good news is that even a little warning makes a big difference, simply because it would allow us to predict the time and location of impact. In the case of 2008 TC3, just a few hours after the asteroid's discovery, NASA scientists completed calculations that predicted an atmospheric plunge over an unpopulated desert area of northern Sudan, with timing accurate to within a minute.
But participants in the planning exercise worried that if an asteroid posing an imminent threat to a populated area were discovered, and the situation were not handled properly, panic and lack of coordination could lead to chaos on the roads.
Spahr was not involved in the exercise, but shares those concerns. "With a three-day warning, you can walk away and be safe. But it scares me, given how poorly we've handled things of this nature in the past," he says, citing the failure to fully evacuate New Orleans ahead of hurricane Katrina in 2005. "I'm picturing people panicking and driving the wrong way on the freeway, screaming 'Oh my god, it's going to kill us!'"
To prevent panic and disorganised movement, it is crucial for authorities to develop an evacuation plan and communicate it to the public as soon as possible after discovery of the dangerous object, since such discoveries are posted automatically online and would cause a media firestorm.
Such measures should ensure the streets would be very quiet as an object such as Innoculatus plunges into the atmosphere and makes its final approach to Washington DC. The compression of the atmosphere in front of the asteroid and friction with the air would cause rapid heating. At lower altitudes, where the air is denser, the heating becomes so intense that the asteroid vaporises and explodes. For the Tunguska event, this happened at about 8 kilometres above ground.
Supersonic shock wave
If you were unfortunate enough to be looking up from directly below, the explosion would be brighter than the sun. The visible and infrared radiation would be strong enough to make anything flammable ignite, says Mark Boslough of Sandia National Laboratory in Livermore, California. "It's like being in a broiler oven," he says. Anyone directly exposed would quickly be very badly burned.
Even before the sound of the blast reaches you, your body would be smashed by a devastating supersonic shock wave as the explosion creates a bubble of high-pressure air that expands faster than the speed of sound. Planetary scientist Jay Melosh of Purdue University in New York once experienced a shock wave from an experiment that exploded 500 tonnes of TNT, a tiny blast in comparison with the blast from an asteroid. "I was standing on top of a hill about 1.5 kilometres away wearing earplugs," he recalls. Melosh says you would see the shockwave in the air due to the way it refracts light. "It's a shimmering bubble," he says. "It spreads out in complete silence until it reaches you, then you hear a double boom."
Melosh was at a safe distance, but at ground zero below an exploding asteroid, the shock wave would be powerful enough to knock down buildings. It would arrive about 30 seconds after the blazing hot flash of light, and could also knock any nearby planes out of the sky, Boslough says. Any surviving buildings would be pummelled by raging winds blowing faster than any hurricane can muster.
Of course, two-thirds of Earth's surface is ocean. While our atmosphere is likely to protect us from asteroids smaller than 100 metres across, anything larger hitting the ocean - including chunks of Innoculatus's rubble pile - would cause a giant splash that could smash coastal buildings with high-speed volleys of water. The tremendous damage and loss of life that would ensue if multiple cities around an ocean basin were flooded led NASA scientists in 2003 to rate ocean impacts by asteroids as far more dangerous than those on or over land.
Recent computer simulations offer some hope, though. They suggest that the monster waves generated by ocean impacts would typically break far from shore, dissipating most of their energy before they could reach cities - unless the impact was very close to the coast, of course. Another ray of hope is that 100-metre asteroids hit Earth only about one-tenth as often as 30-metre objects.
Lasting just one day, the 2008 US air force exercise could barely scratch the surface of the incoming-asteroid problem. Not surprisingly, it discovered that should the nightmare come true, there is no plan for how to coordinate the activities of NASA, emergency planners, the US military and other parts of government. Further planning exercises are needed: the time saved through early preparation will be crucial if an evacuation is ever required at short notice.
Our chance of having any prior warning at all for an approaching 30-metre asteroid is no better than 25 to 35 per cent with existing sky surveillance, calculates astronomer Alan Harris of the Space Science Institute in Boulder, Colorado (see graphic). The sun washes out half of the sky with daylight, blinding us to 50 per cent of threatening objects. Even glare from the moon can hide unwelcome incoming guests.
What's more, two of the world's three leading asteroid surveys are based in Arizona, including the Catalina Sky Survey, which discovered 2008 TC3. The region tends to cloud over between July and September. "Shift 2008 TC3 back to July and forget it. It wouldn't have been seen," says Spahr.
Now picture this ugly scenario, which worried some participants in the air force exercise: an asteroid flies out of nowhere and explodes over a sensitive nuclear-armed region, like South Asia or the Middle East. There's a reasonable chance that such an airburst could be misinterpreted as a nuclear attack. Both produce a bright flash, a blast wave and raging winds.
An asteroid flying out of nowhere and exploding over a sensitive region like the Middle East could be misinterpreted as a nuclear attack
Such concerns were one reason why, when NASA found 2008 TC3 in its sights, it not only issued a press release but also alerted the US State Department, military commanders, and White House officials, says Lindley Johnson at NASA headquarters, who oversees the agency's work on near-Earth objects. "If it had been going down in the middle of the Pacific somewhere, we probably would not have worried too much more about it, but since it was [going to be] on land and near the Middle East, we did our full alerting," he says.
There is one major way to improve our prospects - point more eyes at the skies. The European Space Agency wants to get into the monitoring game and may set its telescopes at the European Southern Observatory in Chile on the problem. This could fill a gap in the NASA-funded surveys, which are limited to watching the skies of the northern hemisphere, says Richard Crowther of the UK's Science and Technology Facilities Council, who is a consultant for ESA and heads a United Nations working group on near-Earth objects.
Be prepared
"Up to now, the US has taken the majority of the responsibility for dealing with this issue and I think it's time for other states to take on a more equitable share of that," he says.
Help will also come from two new US observatories designed to survey the entire sky visible from their locations every few days. The Panoramic Survey Telescope and Rapid Response System (Pan-STARRS), will consist of four 1.8-metre telescopes, the first of which is already up and running in Hawaii. Plans are afoot to construct the 8.4-metre Large Synoptic Survey Telescope in Chile by 2015, though the project is still raising funds. These will improve the chances of an early detection and potentially extend warning times for 30-metre objects to more than a month. But even so, every ground-based lookout suffers from interference from the sun and moon.
A dedicated space telescope would fix this problem, but such a mission could cost more than a billion dollars. "We're talking about investing in an insurance policy," says Irwin Shapiro of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.
Shapiro is leading a US National Research Council panel that by year's end will recommend a strategy to better address the threat from near-Earth objects. That study, along with the air force's report on its asteroid impact exercise, is intended to help the White House develop an official policy on the near-Earth object hazard by October 2010, which Congress has requested.
While asteroid impacts are much rarer than hurricanes and earthquakes, they have the potential to do much greater damage, Johnson warns: "It's not something I think there needs to be billions of dollars per year spent on, but it does warrant some priority in the list of things that we ought to be worried about." The cash would at least give us a better idea of when the next asteroid might strike. "From what we know today," he says, "it could be next week."
Should we panic?
An asteroid blast like the one that flattened Tunguska in Siberia in 1908 is expected only once every 500 years or so, on average. It is likely to be a lot longer than that before one hits a populated area, given how small a fraction of Earth's surface is taken up by cities and towns. A NASA study in 2003 concluded that only one in four Tunguska-like impacts would kill anyone, and only one in 17 such impacts would have a death toll of 10,000 or more, comparable to severe earthquakes and tsunamis.
Can we nuke it?
The fastest way to deflect an asteroid away from Earth would be to send a nuclear bomb aboard a spacecraft, à la the film Deep Impact, though we'd still need several years' warning.
The spacecraft would have to be able to home in on the asteroid and to trigger the explosion at just the right distance. Precision is needed to avoid breaking up the hurtling rock while still giving it enough of a nudge to prevent the Earth impact years down the line.
That assumes we're already prepared. Designing and building new spacecraft typically takes a few years. With current rocket technology, it would probably take several additional years to reach a threatening asteroid. And since the explosion would need to occur years ahead of the predicted impact in order to make the asteroid miss Earth, we'd need decades of lead time if we hoped to deflect Armageddon. A confounding factor is that nukes in space are forbidden by the Outer Space Treaty of 1967, signed by the US, Russia, and other nuclear powers, though they might agree to turn a blind eye on this one.
With several decades of warning time, other deflection technologies could come into play. The gravity tractor, for example, would see a spacecraft hover near the asteroid for several years, gradually pulling the asteroid off its collision course using the tiny gravitational pull of the spacecraft's mass.
Another option would be to focus sunlight on a spot on the asteroid using a fleet of mirror-bearing spacecraft, heating it enough to vaporise rock. The escaping gases would act like the exhaust from a rocket engine, giving the asteroid a slight push in the opposite direction that could produce a substantial course change over many years.
David Shiga is New Scientist's physical sciences reporter in Boston
Find the Air Force Report Here:
http://www.nss.org/resources/library/planetarydefense/index.htm
(See the outstanding video)
http://www.newscientist.com/articlevideo/mg20327271.300/41841503001-asteroid-attack-putting-earths-defences-to-the-test.html
IT LOOKS inconsequential enough, the faint little spot moving leisurely across the sky. The mountain-top telescope that just detected it is taking it very seriously, though. It is an asteroid, one never seen before. Rapid-survey telescopes discover thousands of asteroids every year, but there's something very particular about this one. The telescope's software decides to wake several human astronomers with a text message they hoped they would never receive. The asteroid is on a collision course with Earth. It is the size of a skyscraper and it's big enough to raze a city to the ground. Oh, and it will be here in three days.
Far-fetched it might seem, but this scenario is all too plausible. Certainly it is realistic enough that the US air force recently brought together scientists, military officers and emergency-response officials for the first time to assess the nation's ability to cope, should it come to pass.
They were asked to imagine how their respective organisations would respond to a mythical asteroid called Innoculatus striking the Earth after just three days' warning. The asteroid consisted of two parts: a pile of rubble 270 metres across which was destined to splash down in the Atlantic Ocean off the west coast of Africa, and a 50-metre-wide rock heading, in true Hollywood style, directly for Washington DC.
The exercise, which took place in December 2008, exposed the chilling dangers asteroids pose. Not only is there no plan for what to do when an asteroid hits, but our early-warning systems - which could make the difference between life and death - are woefully inadequate. The meeting provided just the wake-up call organiser Peter Garreston had hoped to create. He has long been concerned about the threat of an impact. "As a taxpayer, I would appreciate my air force taking a look at something that would be certainly as bad as nuclear terrorism in a city, and potentially a civilisation-ending event," he says.
The latest space rock to put the frighteners on us was 2008 TC3. This car-sized object exploded in the atmosphere over Sudan in October last year. A telescope first spotted it just 20 hours before impact - at a distance of 500,000 kilometres - and astronomers say we were lucky to get any warning at all.
Thankfully, 2008 TC3 was far too small to do any damage on the ground, but we are nearly as blind to objects big enough to do serious harm. We have barely begun to track down the millions of skyscraper-sized asteroids zipping around Earth's neighbourhood, any one of which could unleash as much destructive power as a nuclear bomb on impact.
Asteroid impacts are not as rare as you might think. It is widely accepted that an asteroid or comet 30 to 50 metres across exploded over Tunguska in Siberia in 1908, flattening trees for dozens of kilometres all around. The chance of a similar impact is about 1 in 500 each year (Nature, vol 453, p 1178). Put another way, that's a 10 per cent chance of an impact in the next 50 years (see "Should we panic?").
"Fifty-metre asteroids scare me to death," says Timothy Spahr, director of the Minor Planet Center in Cambridge, Massachusetts. "I could easily see a 50-metre object hitting in three days causing absolute pandemonium."
During the US air force planning exercise, the participating scientists explained that with so little warning there would be no hope of preventing an impact. Even Innoculatus's smaller 50-metre asteroid would weigh hundreds of thousands of tonnes, requiring an enormous push to change its trajectory appreciably - so much so that detonating a nuke near it in space would not provide a sufficient impulse so late in the game to cause a miss. To deflect an asteroid sufficiently, force would need to be applied years in advance (see "Could we nuke it?").
In fact, it could make things worse by breaking the asteroid into pieces, some of which could be large enough to do damage, and even create a blizzard of meteors that would destroy satellites in Earth orbit.
Panic on the streets
Realistically, though, the nuclear option would not be on the table in the first place: the nuclear-tipped missiles sitting patiently in silos around the world are not designed to track and home in on an asteroid or even survive for more than a few minutes in space. Instead, we would simply have to brace ourselves for the impact.
The good news is that even a little warning makes a big difference, simply because it would allow us to predict the time and location of impact. In the case of 2008 TC3, just a few hours after the asteroid's discovery, NASA scientists completed calculations that predicted an atmospheric plunge over an unpopulated desert area of northern Sudan, with timing accurate to within a minute.
But participants in the planning exercise worried that if an asteroid posing an imminent threat to a populated area were discovered, and the situation were not handled properly, panic and lack of coordination could lead to chaos on the roads.
Spahr was not involved in the exercise, but shares those concerns. "With a three-day warning, you can walk away and be safe. But it scares me, given how poorly we've handled things of this nature in the past," he says, citing the failure to fully evacuate New Orleans ahead of hurricane Katrina in 2005. "I'm picturing people panicking and driving the wrong way on the freeway, screaming 'Oh my god, it's going to kill us!'"
To prevent panic and disorganised movement, it is crucial for authorities to develop an evacuation plan and communicate it to the public as soon as possible after discovery of the dangerous object, since such discoveries are posted automatically online and would cause a media firestorm.
Such measures should ensure the streets would be very quiet as an object such as Innoculatus plunges into the atmosphere and makes its final approach to Washington DC. The compression of the atmosphere in front of the asteroid and friction with the air would cause rapid heating. At lower altitudes, where the air is denser, the heating becomes so intense that the asteroid vaporises and explodes. For the Tunguska event, this happened at about 8 kilometres above ground.
Supersonic shock wave
If you were unfortunate enough to be looking up from directly below, the explosion would be brighter than the sun. The visible and infrared radiation would be strong enough to make anything flammable ignite, says Mark Boslough of Sandia National Laboratory in Livermore, California. "It's like being in a broiler oven," he says. Anyone directly exposed would quickly be very badly burned.
Even before the sound of the blast reaches you, your body would be smashed by a devastating supersonic shock wave as the explosion creates a bubble of high-pressure air that expands faster than the speed of sound. Planetary scientist Jay Melosh of Purdue University in New York once experienced a shock wave from an experiment that exploded 500 tonnes of TNT, a tiny blast in comparison with the blast from an asteroid. "I was standing on top of a hill about 1.5 kilometres away wearing earplugs," he recalls. Melosh says you would see the shockwave in the air due to the way it refracts light. "It's a shimmering bubble," he says. "It spreads out in complete silence until it reaches you, then you hear a double boom."
Melosh was at a safe distance, but at ground zero below an exploding asteroid, the shock wave would be powerful enough to knock down buildings. It would arrive about 30 seconds after the blazing hot flash of light, and could also knock any nearby planes out of the sky, Boslough says. Any surviving buildings would be pummelled by raging winds blowing faster than any hurricane can muster.
Of course, two-thirds of Earth's surface is ocean. While our atmosphere is likely to protect us from asteroids smaller than 100 metres across, anything larger hitting the ocean - including chunks of Innoculatus's rubble pile - would cause a giant splash that could smash coastal buildings with high-speed volleys of water. The tremendous damage and loss of life that would ensue if multiple cities around an ocean basin were flooded led NASA scientists in 2003 to rate ocean impacts by asteroids as far more dangerous than those on or over land.
Recent computer simulations offer some hope, though. They suggest that the monster waves generated by ocean impacts would typically break far from shore, dissipating most of their energy before they could reach cities - unless the impact was very close to the coast, of course. Another ray of hope is that 100-metre asteroids hit Earth only about one-tenth as often as 30-metre objects.
Lasting just one day, the 2008 US air force exercise could barely scratch the surface of the incoming-asteroid problem. Not surprisingly, it discovered that should the nightmare come true, there is no plan for how to coordinate the activities of NASA, emergency planners, the US military and other parts of government. Further planning exercises are needed: the time saved through early preparation will be crucial if an evacuation is ever required at short notice.
Our chance of having any prior warning at all for an approaching 30-metre asteroid is no better than 25 to 35 per cent with existing sky surveillance, calculates astronomer Alan Harris of the Space Science Institute in Boulder, Colorado (see graphic). The sun washes out half of the sky with daylight, blinding us to 50 per cent of threatening objects. Even glare from the moon can hide unwelcome incoming guests.
What's more, two of the world's three leading asteroid surveys are based in Arizona, including the Catalina Sky Survey, which discovered 2008 TC3. The region tends to cloud over between July and September. "Shift 2008 TC3 back to July and forget it. It wouldn't have been seen," says Spahr.
Now picture this ugly scenario, which worried some participants in the air force exercise: an asteroid flies out of nowhere and explodes over a sensitive nuclear-armed region, like South Asia or the Middle East. There's a reasonable chance that such an airburst could be misinterpreted as a nuclear attack. Both produce a bright flash, a blast wave and raging winds.
An asteroid flying out of nowhere and exploding over a sensitive region like the Middle East could be misinterpreted as a nuclear attack
Such concerns were one reason why, when NASA found 2008 TC3 in its sights, it not only issued a press release but also alerted the US State Department, military commanders, and White House officials, says Lindley Johnson at NASA headquarters, who oversees the agency's work on near-Earth objects. "If it had been going down in the middle of the Pacific somewhere, we probably would not have worried too much more about it, but since it was [going to be] on land and near the Middle East, we did our full alerting," he says.
There is one major way to improve our prospects - point more eyes at the skies. The European Space Agency wants to get into the monitoring game and may set its telescopes at the European Southern Observatory in Chile on the problem. This could fill a gap in the NASA-funded surveys, which are limited to watching the skies of the northern hemisphere, says Richard Crowther of the UK's Science and Technology Facilities Council, who is a consultant for ESA and heads a United Nations working group on near-Earth objects.
Be prepared
"Up to now, the US has taken the majority of the responsibility for dealing with this issue and I think it's time for other states to take on a more equitable share of that," he says.
Help will also come from two new US observatories designed to survey the entire sky visible from their locations every few days. The Panoramic Survey Telescope and Rapid Response System (Pan-STARRS), will consist of four 1.8-metre telescopes, the first of which is already up and running in Hawaii. Plans are afoot to construct the 8.4-metre Large Synoptic Survey Telescope in Chile by 2015, though the project is still raising funds. These will improve the chances of an early detection and potentially extend warning times for 30-metre objects to more than a month. But even so, every ground-based lookout suffers from interference from the sun and moon.
A dedicated space telescope would fix this problem, but such a mission could cost more than a billion dollars. "We're talking about investing in an insurance policy," says Irwin Shapiro of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.
Shapiro is leading a US National Research Council panel that by year's end will recommend a strategy to better address the threat from near-Earth objects. That study, along with the air force's report on its asteroid impact exercise, is intended to help the White House develop an official policy on the near-Earth object hazard by October 2010, which Congress has requested.
While asteroid impacts are much rarer than hurricanes and earthquakes, they have the potential to do much greater damage, Johnson warns: "It's not something I think there needs to be billions of dollars per year spent on, but it does warrant some priority in the list of things that we ought to be worried about." The cash would at least give us a better idea of when the next asteroid might strike. "From what we know today," he says, "it could be next week."
Should we panic?
An asteroid blast like the one that flattened Tunguska in Siberia in 1908 is expected only once every 500 years or so, on average. It is likely to be a lot longer than that before one hits a populated area, given how small a fraction of Earth's surface is taken up by cities and towns. A NASA study in 2003 concluded that only one in four Tunguska-like impacts would kill anyone, and only one in 17 such impacts would have a death toll of 10,000 or more, comparable to severe earthquakes and tsunamis.
Can we nuke it?
The fastest way to deflect an asteroid away from Earth would be to send a nuclear bomb aboard a spacecraft, à la the film Deep Impact, though we'd still need several years' warning.
The spacecraft would have to be able to home in on the asteroid and to trigger the explosion at just the right distance. Precision is needed to avoid breaking up the hurtling rock while still giving it enough of a nudge to prevent the Earth impact years down the line.
That assumes we're already prepared. Designing and building new spacecraft typically takes a few years. With current rocket technology, it would probably take several additional years to reach a threatening asteroid. And since the explosion would need to occur years ahead of the predicted impact in order to make the asteroid miss Earth, we'd need decades of lead time if we hoped to deflect Armageddon. A confounding factor is that nukes in space are forbidden by the Outer Space Treaty of 1967, signed by the US, Russia, and other nuclear powers, though they might agree to turn a blind eye on this one.
With several decades of warning time, other deflection technologies could come into play. The gravity tractor, for example, would see a spacecraft hover near the asteroid for several years, gradually pulling the asteroid off its collision course using the tiny gravitational pull of the spacecraft's mass.
Another option would be to focus sunlight on a spot on the asteroid using a fleet of mirror-bearing spacecraft, heating it enough to vaporise rock. The escaping gases would act like the exhaust from a rocket engine, giving the asteroid a slight push in the opposite direction that could produce a substantial course change over many years.
David Shiga is New Scientist's physical sciences reporter in Boston
Find the Air Force Report Here:
http://www.nss.org/resources/library/planetarydefense/index.htm
23 May 2009
NASA, NSS, and Secure World Foundation Post Air Force Report on Interagency Asteroid Scenario
http://neo.jpl.nasa.gov/neo/niaa2008.html
http://www.nss.org/resources/library/planetarydefense/2008-NaturalImpactAfterActionReport.pdf
http://planetarydefense.blogspot.com/2009/04/dod-tabletop-exercise-on-planetary.html
Secure World provides a useful summary:
From: http://www.secureworldfoundation.org/blog/2009/04/natural-impact-event-interagency.html
Natural Impact Event Interagency Planning Exercise
The U.S. Air Force Future Concepts and Transformation Division hosted a Natural Impact Event Interagency Planning Exercise on December 4, 2008, in Alexandria, Virginia. Twenty Seven Subject Matter Experts from across US Government, including the Departments of Defense, Energy, State, Homeland Security; the National Aeronautics and Space Administration (NASA) and the National Security Council (NSC) participated in a single day tabletop exercise to explore “whole of government” response to an impending asteroid strike. Peter Anthony Garretson (Council of Foreign Relations) and Lindley N. Johnson (Planetary Science Division, HQ NASA) also wrote a paper summarizing the findings.The specific scenario involved a mythical asteroid, “2008 Innoculatus.” It was a binary asteroid consisting of a 270-meter rocky rubble pile projected to strike the Gulf of Guinea and a 50-meter metallic companion asteroid projected to strike in the National Capital Region (NCR). The scenario was selected to maximize exposure to the diversity of threat (variation in size, composition, land/water strike), stress both national and international notification, and provide useful pre-planning should an actual effort need to be mounted against the asteroid Apophis when it has a small probability to pass through a gravitational keyhole in 2029 and perhaps return to strike the Earth seven years later in 2036. Players were broken into two teams. The first team focused on disaster response and was told the asteroid was discovered 72 hours from impact. The second team focused on deflection/mitigation was told the asteroid had been discovered seven years from impact, and to design a “strawman” deflection plan using existing capabilities. Major findings include:
- The NEO impact scenario is not captured in existing plans
- The NEO impact scenario should be elevated to higher level exercises with more senior players
- Proper planning and response to a NEO emergency requires delineation of organizational responsibilities including lead agency and notification standards,
- Players were not able to achieve consensus on which agency should lead the NEO deflection/mitigation effort
- There is a deficit in software tools to support senior decision-making and strategic communication for disaster response and mitigation for a NEO scenario
- There are significant effects a NEO impact would generate that are not adequately captured in existing models
- The public may be aware of an impending NEO impact before senior decision-makers
- Lead time for evacuation requires decisions be made before best information is available
- Public safety and tranquility require that the federal government be able to rapidly establish a single authoritative voice and tools to present critical information
- The preferred approach for short-notice NEO deflection was stand-off nuclear
18 April 2009
Air Force Looking At Space Solar Power
Air Force Looking At Space-Based Solar Power Possibilities, Inside theAir Force, January 30, 2009
The Air Force is looking at space-based power technology as a way toprovide "metropolitan-class" energy for the nation as well as possiblybeaming megawatts of electricity directly to forward-deployed bases,according to the service's chief scientist. The general idea behind thisinitiative is to place large solar arrays or reflectors intogeosynchronous orbit, Air Force Chief Scientist Werner Dahm told Inside the Air Force during a Jan. 26 interview in his Pentagon office. The arrays could generate their own power, while the reflectors could reflect the Sun's light and concentrate it onto smaller arrays or a"heat engine" to generate power. The energy created could then be beamedto the ground by way of microwave transmission. The energy collector onEarth would most likely be placed in the desert, because the receiving suite would have to be roughly 10 kilometers in diameter, according to Dahm. ITAF reported earlier this month that Air Force infrastructure or energy projects originally planned to begin several years down the road could be initiated earlier than expected so that they could be paid forby a government stimulus plan as a way of creating millions of dollarsfor domestic jobs. The "national" solar-based power concept is to place"metropolitan-scale systems" -- or those that produce 25 gigawatts ofpower, more than that which is needed to power New York City -- intospace, Dahm said. These systems would need solar arrays that are 2.5 kilometers by 5 kilometers in area. "They're so large, people tend togiggle, but you have to remind yourself that you're getting down 25 gigawatts of power," he said.
The Air Force is looking at space-based power technology as a way toprovide "metropolitan-class" energy for the nation as well as possiblybeaming megawatts of electricity directly to forward-deployed bases,according to the service's chief scientist. The general idea behind thisinitiative is to place large solar arrays or reflectors intogeosynchronous orbit, Air Force Chief Scientist Werner Dahm told Inside the Air Force during a Jan. 26 interview in his Pentagon office. The arrays could generate their own power, while the reflectors could reflect the Sun's light and concentrate it onto smaller arrays or a"heat engine" to generate power. The energy created could then be beamedto the ground by way of microwave transmission. The energy collector onEarth would most likely be placed in the desert, because the receiving suite would have to be roughly 10 kilometers in diameter, according to Dahm. ITAF reported earlier this month that Air Force infrastructure or energy projects originally planned to begin several years down the road could be initiated earlier than expected so that they could be paid forby a government stimulus plan as a way of creating millions of dollarsfor domestic jobs. The "national" solar-based power concept is to place"metropolitan-scale systems" -- or those that produce 25 gigawatts ofpower, more than that which is needed to power New York City -- intospace, Dahm said. These systems would need solar arrays that are 2.5 kilometers by 5 kilometers in area. "They're so large, people tend togiggle, but you have to remind yourself that you're getting down 25 gigawatts of power," he said.
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