PCAST Public Statement on Space Solar Power

Readers of this blog know that Open.gov's #1 public suggestion for NASA, DOE, and OSTP was to hold a conference on Space-Based Solar Power   OSTP administers the President's Council of Advisors on Science and Technology (PCAST)

President Obama specifically tasked the PCAST with providing him with Energy related scientific advice, including: "But energy is our great project, this generation's great project. And that's why I've set a goal for our nation that we will reduce our carbon pollution by more than 80 percent by 2050... I will charge PCAST with advising me about national strategies to nurture and sustain a culture of scientific innovation."

PCAST recently had a meeting where Mr. John Mankins, President of Artemis Innovation Solutions gave a public statement.  

Mr. Mankins has a 25-year career at NASA and JPL, including 10 years as the manager of Advanced Concepts Studies at NASA, and was the manager of Exploration Systems Research and Technlogy overseeing nearly a billion dollar budget of over 100 individual projects and some 3000 personnel.  

Check out what he had to say about Space Solar Power:

COMMENTS TO THE PRESIDENT’S COUNCIL OF ADVISORS ON SCIENCE AND TECHNOLOGY WRITTEN STATEMENT

An Opportunity for Transformation: Space Solar Power

16 July 2010

John C. Mankins President, Artemis Innovation Management Solutions LLC1

To meet the challenges of Energy and the Environment in an increasingly interdependent and competitive world, novel policies and systems concepts must be pursued. Space activities are not generally considered as relevant to these global challenges outside of Earth observing, global positioning, and the like.

However, this may be an oversight of great significance.  

A space program goal that could--if achieved--radically change the dynamic for renewable energy is that of space solar power: the capability to deliver on demand energy gathered in space to global markets almost continuously.

Unfortunately, as things now stand the US can scarcely even consider this revolutionary goal. No Agency combines the right mix of responsibilities for security, space development, U.S. energy needs, and international relations. DOE is responsible for energy, not space. NASA is responsible for space and aeronautics, not energy. And so on. And with constrained budgets no Agency is looking to add additional goals to their current responsibilities.

Also, some believe the concept of space solar power is impossible. Such views are based largely on conviction, not engineering. Not for more than a decade has there been in the US a systematic, end--to--end study of the concept, nor any meaningful R&D.

And look how far non--space technology has progressed in the past 10 years. Why should space solar power be impossible, except that it is that we have assumed it is so. Basing policies and programs on such assumptions is no recipe for innovation.  

In fact, in 2000 an independent National Research Council review committee found that space solar power was already then technically feasible and that the only R&D issues to resolve involve the question of eventual economic viability. 

The revolutionary new systems concept that could enable space solar power is that of intelligent modular systems building truly enormous future space capabilities out of many hundreds and thousands of smaller component systems. This concept applies to space the principals and architectures of networked systems from hives of bees to cloud computing.

Of course, diverse new technologies still in the laboratory must be proven for space solar power in wireless power transmission, robotics, materials, electronics, and other areas. And numerous new supporting infrastructures will be needed, including low cost launch, affordable in-- space transportation, and others. But, recall how the steam engine changed the world and it was first fabricated from known materials by adult craftsmen working in existing shops. Similar systems--level revolutions resulted from internal combustion, electrification, and heavier than air flight. Although innumerable breakthroughs followed, the beginnings of each lay in new concepts, visionary investments and focused development. 

In the same way, no breakthroughs are required to build the first space solar power pilot plants.

I believe that in a decade or less, the first space solar power pilot plant could be in orbit, delivering to people in multiple countries both clean energy, and a new vision of the interconnectedness of space and Earth. And that within a generation, space solar power could be established as a competitive green energy source in markets worldwide.

Certainly, a revolution in technology, such as space solar power is urgently needed one that would allow the US, working with others to deliver by mid century 100s of thousands of megawatts of carbon--free power to global markets.

The concept of space solar power is under consideration in several countries around the world, ranging from India where key groups and a former President have proposed an international study of the idea, to Japan where space solar power is already an official goal of the Japanese space program. This is a unique moment when the US could demonstrate critical, catalytic leadership working with friends around the world to explore an already technically feasible but fundamentally new and sustainable source of energy.

I urge the PCAST to give consideration to space solar power as a prospective national--level goal that could enhance and engage the best of U.S. government competencies, business capabilities and international relations.

Thank you for this opportunity to present these views to the Council. A copy of my oral statement to the PCAST is appended, as are extensive references on the topic of space solar power.

Appendix 2 Discussion Points for OSTP / PCAST Public Statement

Meeting the dual challenges of Energy and the Environment in an interdependent and competitive world demands novel policies and systems concepts. Space activities are not generally considered as relevant to these global challenges outside of Earth observing, global positioning, and the like.

However, this may be an oversight of great significance.

A space program goal that could if achieved radically change the dynamic for renewable energy internationally is that of space solar power: the capability to deliver on demand energy gathered in space to global markets almost continuously.

Unfortunately, as things now stand the US can scarcely even consider this revolutionary goal. No Agency combines the right mix of responsibilities for security, space development, U.S. energy, and international relations. The DOE is responsible for energy, not space. NASA is responsible for space and aeronautics, not energy. And so on.

And, some believe space solar power is impossible. However, such views are based largely on conviction, not engineering. For over a decade the US has conducted no systematic, end--to--end study of this concept, nor any meaningful R&D.

Of course, diverse technologies must be proven for space solar power in wireless power transmission, robotics, and other areas. But, recall how the steam engine changed the world and it was first fabricated from known materials by craftsmen working in existing shops.

In a decade or less, the first space solar power pilot plant could be in orbit, delivering to people in multiple countries clean energy, and a new vision of the interconnectedness of space and Earth.  

Clearly, a revolution is needed one that can enable the US, working with others to deliver by mid century 100s of thousands of megawatts of carbon--free power to global markets. 

I urge the PCAST to give consideration to space solar power as a prospective national--level goal that could enhance and engage the best of U.S. government competencies, business capabilities and international relations.

1 For additional Information, please contact: John C. Mankins; President, Artemis Innovation Management Solutions LLC; P.O. Box

6660, Santa Maria, California

93456 USA; email: john.c.mankins@artemisinnovation.com; website: http://www.artemisinnovation.com.

Appendix 1 Selected Bibliography of Relevant References Key References

Feingold, Harvey, et al, Space Solar Power A Fresh Look at the Feasibility of Generating Solar Power in Space for Use on Earth (SAIC; Schaumberg, Illinois, USA). 02 April 1997.

Glaser, Peter, Ph.D.; Method and Apparatus for Converting Solar Radiation to Electrical Power.(US Patent No. 3,781,647; U.S. Patent and Trademark Office; Washington, D.C.)

25 December 1973.

Howell, Joseph T. and Mankins, John C., Highly Reusable Space Transportation A Summary Report; Retrospective 2009 (Presented at the International Symposium on Solar Energy from Space / IAA SPS 2009 Workshop; Toronto, Canada). 8--11 September 2009.

Mankins, John C. and Kaya, Nobuyuki, A Report On The Status of the IAA Study Group on Solar Energy from Space, IAC--C3.1.1 (Presented at the 60th International Astronautical Congress; Daejeon, Republic of Korea). October 2009.

Mankins, John C. and Howell, Joseph T.; Overview of the Space Solar Power Exploratory Research and Technology Program ---- AIAA 2000--3060 (35th Intersociety Energy Conversion Engineering Conference; Las Vegas, Nevada USA). 24--28 July 2000.

National Research Council, Aeronautics and Space Engineering Board, Committee for the Assessment of NASA's Space Solar Power Investment Strategy, Aeronautics and Space Engineering Board, Laying the Foundation for Space Solar Power: An Assessment of NASA's Space Solar Power Investment Strategy. (National Academies Press; Washington, D.C. USA). 2001.

Additional References

Brandhorst, Henry; Megawatt SEPS and Mars Exploration(International Symposium on Solar Energy from Space / SPS 2009 at the Ontario Science Center; Toronto, Canada). 810 September 2009.

Criswell, David R., Power Collection and Transmission System and Method

(US Patent No. 3,781,647; U.S. Patent and Trademark Office; Washington, D.C.)

28 May 1991.

Commercial Space Transportation Study Team, Commercial Space Transport Study Final Report,(Distributed by W. Piland, NASA Langley Research Center; Hampton, Virginia; USA). April 1994.

Ignatiev, Alex, Ph.D., Opportunities to Employ Lunar Surface Materials in a Future Space Solar Power Economy, (Presented at the International Symposium on Solar Energy from Space / IAA SPS 2009 Workshop; Toronto, Canada). 8--11 September 2009.

Kaya, Nobuyuki; Mankins, John C.; Iwashita, Masashi; Little, Frank; and Marzwell, Neville; Hawaii Demonstation of Microwave Beam Control, supported by the Discovery Channel; (International Symposium on Solar Energy from Space / SPS 2009 at the Ontario Science Center; Toronto, Canada). 8--10 September 2009.

Kaya, Nobuyuki, et al.; Crawling Robots On Large Web In Rocket Experiment On Furoshiki Deployment (55th International Astronautical Congress; Vancouver, Canada). 2004.

Mankins, John C., Space Solar Power: A Fresh Look, AIAA

95--3653 (Presented at the 1995 AIAA Space Programs and Technologies Conference, Huntsville, Alabama). September 1995.

Penn, Jay, and Law, Glenn, Future SSP Systems Concepts: the Laser Option.

Commercial and Military Applications, (Presented at the International Symposium on Solar Energy from Space / IAA SPS 2009 Workshop; Toronto, Canada).

8--11 September 2009.

Mankins, John C., A Technical Overview Of The SunTower Solar Power Satellite Concept (IAF--97--R.2.08; 38th International Astronautical Federation, Turin, Italy)

6--10 October 1997.

Mankins, John C.; An Affordable Lunar Launch Concept: MagLifter on the Moon

(revisiting the Lunatron); (International Symposium on Solar Energy from Space / SPS

2009 at the Ontario Science Center; Toronto, Canada).

8--10 September 2009.

Mankins, John C.; Technology Readiness Levels Definitions (White Paper NASA Headquarters; Washington, D.C.; USA). 1995.

Mankins, John C.; Research & Development Degree of Difficulty A White Paper

(White Paper, Advanced Projects Office, NASA Headquarters; Washington, D.C.; USA).

10 March1998. McSpadden, James; Advances in RF Wireless Power Transmission;

(International Symposium on Solar Energy from Space / SPS 2009 at the Ontario Science Center; Toronto, Canada). 8--10 September 2009.

Mihara, Shoichiro; Fuse, Yoshiharu; Saito, Takashi, and Ijichi, Koichi; WPT Technology Demonstration Options at USEF; (International Symposium on Solar Energy from Space / SPS 2009 at the Ontario Science Center; Toronto, Canada). 8--10 September 2009.

Office of Technology Assessment, US Congress; Solar Power Satellites. (Washington DC.) 1981.

Powell, James, R., Maise, George and Rather, John, Maglev Launch An Ultra Low Cost Way to Deploy Space Solar Power Systems (Presented at the International Symposium on Solar Energy from Space / IAA SPS 2009Workshop; Toronto, Canada).

8--11 September 2009.

Full NRC Report! Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies: Final Report

Above are the links for both the Interim and the Just-Released Final Report.  Here are the Findings and Recommendations of the Final Report:

• Finding: Congress has mandated that NASA discover 90 percent of all near-Earth objects 140 meters in diameter or greater by 2020. The administration has not requested and Congress has not appropriated new funds to meet this objective. Only limited facilities are currently involved in this survey/discovery effort, funded by NASA’s existing budget.
• Finding: The current near-Earth object surveys cannot meet the goals of the 2005 George E. Brown, Jr. Near-Earth Object Survey Act directing NASA to discover 90 percent of all near-Earth objects 140 meters in diameter or greater by 2020.
• Finding: The selected approach to completing the George E. Brown, Jr. Near-Earth Object Survey will depend on nonscientific factors:
• If completion of the survey as close to the original 2020 deadline as possible is considered most important, a space mission conducted in concert with observations using a suitable ground-based telescope and selected by peer-reviewed competition is the best approach.
• This combination could complete the survey well before 2030, perhaps as early as 2022 if funding were appropriated quickly.
• If cost conservation is deemed most important, the use of a large ground-based telescope is the best approach. Under this option, the survey could not be completed by the original 2020 deadline, but could be completed before 2030. To achieve the intended cost effectiveness, the funding to construct the telescope must come largely on the basis of non-NEO programs.
• Recommendation: Because recent studies of meteor airbursts have suggested that near-Earth objects as small as 30 to 50 meters in diameter could be highly destructive, surveys should attempt to detect as many 30- to 50-meter objects as possible. This search for smaller-diameter objects should not be allowed to interfere with the survey for objects 140-meters in diameter or greater.
• Finding: The Arecibo and Goldstone radar systems play a unique role in the characterization of NEOs, providing unmatched accuracy in orbit determination, and insight into size, shape, surface structure, and other properties for objects within their latitude coverage and detection range.
• Recommendation: Immediate action is required to ensure the continued operation of the Arecibo Observatory at a level sufficient to maintain and staff the radar facility. Additionally, NASA and NSF should support a vigorous program of radar observations of NEOs at Arecibo and NASA should support such a program at Goldstone for orbit determination and characterization of physical properties.
• Recommendation: The United States should initiate a peer-reviewed, targeted research program in the area of impact hazard and mitigation of NEOs. Because this is a policy driven, applied program, it should not be in competition with basic scientific research programs or funded from them. This research program should encompass three principal task areas: surveys, characterization, and mitigation. The scope should include analysis, simulation, and laboratory experiments. This research program does not include mitigation space experiments or tests which are treated elsewhere in this report.
• Recommendation: The United States should take the lead in organizing and empowering a suitable international entity to participate in developing a detailed plan for dealing with the NEO hazard.
• Recommendation: Data from NEO airburst events observed by the U.S. Department of Defense satellites should be made available to the scientific community to allow it to improve understanding of the NEO hazards to Earth.
• -----------------
• Finding: The mandated survey to locate 90 percent of near-Earth objects 140-meters in diameter or greater has not yet been funded by the federal government. Because the survey requires several years to budget and build new equipment, and then to conduct the search, completion by 2020 is not realistic.
• Finding: The selected approach to completing the George E. Brown, Jr. Near-Earth Object Survey will depend on nonscientific factors:
• • If completion of the survey as close to the original 2020 deadline as possible is considered most important, a space mission conducted in concert with observations using a suitable ground-based telescope and selected by peer-reviewed competition is the best approach. This combination could complete the survey well before 2030, perhaps as early as 2022 if funding were appropriated quickly.
• • If cost conservation is deemed most important, the use of a large ground-based telescope is the best approach. Under this option, the survey could not be completed by the original 2020 deadline, but could be completed before 2030. To achieve the intended cost-effectiveness, the funding to construct the telescope must come largely on the basis of non-NEO programs.
• Finding: It is highly probable that the next destructive NEO event will be an airburst from a <50- meter object, not a crater-forming impact.
• Recommendation: Because recent studies of meteor airbursts have suggested that near-Earth objects as small as 30 to 50 meters in diameter could be highly destructive, surveys should attempt to detect as many 30- to 50-meter objects as possible. This search for smaller-diameter objects should not be allowed to interfere with the survey for objects 140-meters in diameter or greater.
• Finding: The best opportunities for physical characterization of most NEOs occur during close Earth approaches when these objects are optically bright. Existing programs of ground-based optical observations for characterization of NEOs are few in number, and are not coordinated among different observing teams. Many observable NEOs are not characterized.
• Finding: The capabilities of Arecibo and Goldstone are complementary and many observing campaigns have utilized their synergy. One of the primary advantages of having two radar facilities is that one can serve as a backup for the other.
• Finding: The number of NEOs observed by radar per year could be increased about fivefold by obtaining sufficient observing time.
• Finding: Radar cannot be used to discover NEOs, but is a powerful tool for rapidly improving our knowledge of the orbit of a newly found object, and thus characterizing its potential hazard to Earth.
• Finding: The Arecibo and Goldstone radar systems play a unique role in the characterization of NEOs, providing unmatched accuracy in orbit determination, and insight into size, shape, surface structure, and other properties for objects within their latitude coverage and detection range.
• Finding: Congress has directed NASA to ensure that Arecibo is available for radar observations, but has not appropriated funds for this work.
• Recommendation: Immediate action is required to ensure the continued operation of the Arecibo Observatory at a level sufficient to maintain and staff the radar facility. Additionally, NASA and NSF should support a vigorous program of radar observations of NEOs at Arecibo and NASA should support such a program at Goldstone for orbit determination and characterization of physical properties.
• Finding: U.S. Department of Defense satellites have detected and continue to detect high-altitude airburst events from NEOs entering Earth’s atmosphere. Such data are valuable to the NEO community for assessing NEO hazards.
• Recommendation: Data from NEO airburst events observed by the U.S. Department of Defense satellites should be made available to the scientific community to allow it to improve understanding of the NEO hazards to Earth.
• Finding: Preliminary theoretical studies on low-altitude atmospheric Tunguska-like airbursts from asteroids as small as 30 meters in diameter suggest significant risk exists from these NEOs.
• Finding: Current models for generation of tsunamis by impacts into, or airbursts above, the ocean are not yet sufficiently reliable to establish threat levels to coastal communities.
• Recommendation: Additional observations and modeling should be performed to establish the risk associated with airbursts and with potential tsunami generation.
• Finding: Dedicated flyby spacecraft missions to NEOs provide only limited information relevant for hazard mitigation issues.
• Finding: Rendezvous spacecraft missions can provide detailed characterization of NEOs that could aid in the design and development of hazard-mitigation techniques. Such in situ characterization also allows calibration of ground- and space-based remote sensing data and may permit increased confidence in the use of remote classification of NEOs to inform future mitigation decisions.
• Recommendation: If NASA conducts human missions to NEOs, these missions should maximize the data obtained for NEO characterization.
• Finding: No single approach to mitigation is appropriate and adequate to fully prevent the effects of the full range of potential impactors, although civil defense is an appropriate component of mitigation in all cases. With adequate warning, a suite of four types of mitigation is adequate to mitigate the threat from nearly all NEOs except the most energetic ones.
• Finding: Civil defense (evacuation, sheltering in place, providing emergency infrastructure) is a cost-effective mitigation measure for saving lives from the smallest NEO impact events and is a necessary part of mitigation for larger events. If an NEO is predicted to impact on a specific, inhabited location, there is likely to be strong pressure for more than the most cost-effective method for saving lives.
• Finding: Slow-push-pull techniques are the most accurately controllable and are adequate for changing the orbits of small NEOs (tens of meters to roughly 100 m in diameter) with decades of advance warning and for somewhat larger NEOs (hundreds of meters) in those few cases where it would pass through a keyhole that would put the NEO onto an impact trajectory. Of the slow push/pull techniques, the gravity tractor appears to be the most independent of variations in the properties of the NEO and by far the closest to technological readiness.
• Finding: Kinetic impactors are adequate to prevent impacts on Earth by moderately sized NEOs (many hundreds of meters to 1 kilometer) with decades of advance warning. The concept has been demonstrated in space, but the result is sensitive to the properties of the NEO and requires further study.
• Finding: Unless a large flotilla (100 or more) of massive spacecraft was sent as impactors, nuclear explosions are the only current, practical means for changing the orbit of large NEOs (diameters greater than about 1 km). They also remain as a backup strategy for somewhat smaller objects if other methods have failed. They may be the only method for dealing with smaller objects when warning time is short, but additional research is necessary for these cases.
• Finding: For a wide range of impact scenarios, launch capability exists to deliver an appropriate payload to mitigate an NEO. For some scenarios, particularly short warning scenarios, the capability is inadequate. Development of foreseen heavy-lift launch vehicles, such as the Ares cargo vehicle, should enable the use of a variety of methods for NEOs up to 2 times larger than is possible with current launch vehicles
• Finding: Mitigation of the threat from NEOs benefits dramatically from in-situ characterization of the NEO prior to mitigation, if there is time to do so.
• Finding: Changing the orbit of an NEO with our current understanding is sufficiently uncertain that, in most cases, it requires an accompanying verification. This is easy to implement with many slow-push techniques but requires considerable additional effort for other techniques.
• Recommendation: If Congress chooses to fund mitigation research at an appropriately high level, the first priority for a space mission in the mitigation area is an experimental test of a kinetic impactor along with a characterization, monitoring and verification system, such as the Don Quijote mission that was previously considered, but not funded, by ESA. This mission would produce the most significant advances in understanding and provide an ideal chance for international collaboration in a realistic mitigation scenario.
• Recommendation: The United States should initiate a peer-reviewed, targeted research program in the area of impact hazard and mitigation of NEOs. Because this is a policy driven, applied program, it should not be in competition with basic scientific research programs or funded from them. This research program should encompass three principal task areas: surveys, characterization, and mitigation. The scope should include analysis, simulation, and laboratory experiments. This research program does not include mitigation space experiments or tests which are treated elsewhere in this report.
• Recommendation: The United States should establish a standing committee with membership from each of the relevant agencies and departments, to develop a detailed plan for treating all aspects of the threat posed to Earth by NEOs, and apportioning among these agencies and departments authority and responsibility for carrying out this plan, in coordination and collaboration with other nations. The committee would be further charged with overseeing on a continuing basis the carrying out of each agency’s and department’s activities under this plan. The Administration should designate one agency or department as the lead; the chair of the committee should be the representative from this agency or department.
• Recommendation: The United States should take the lead in organizing and empowering a suitable international entity to participate in developing a detailed plan for dealing with the NEO hazard.
• Finding: A $10 million annual level of funding would be sufficient to continue existing surveys, maintain the radar capability at the Arecibo and Goldstone observatories, and support a modest level of research on the hazards posed by NEOs. This level would not allow achievement of the goals established in the George E. Brown, Jr. Near-Earth Object Survey Act on any timescale. A $50 million annual level of funding for several years would likely be sufficient to achieve the goals of the George E. Brown, Jr. Near-Earth Object Survey Act. A $250 million annual level of funding if continued for somewhat under a decade, would be sufficient to accomplish the survey and research objectives, plus provide survey redundancy and support for a space mission to test in situ characterization and mitigation.

NRC Report is out!: Bigger, Better Telescopes Needed to Find Near-Earth Asteroids

From: http://www.wired.com/wiredscience/2010/01/bigger-better-telescopes-needed-to-find-near-earth-asteroids/

If we’re going to protect the Earth from an asteroid, we need to find the dangerous ones whizzing about in the emptiness of space.

Unfortunately, the United States will not complete the survey of large near-Earth objects by 2020 as mandated, but not funded, by Congress in 2005. That’s the conclusion of a new National Research Council Report,Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies, released Friday.

The current budget and astronomical tools are just not sufficient to find all near-Earth objects larger than 140 meters (460 feet) across. Better telescopes than we currently have will be needed. While this has been known within the NEO science community, the final report could bring the realization to the policymakers and politicians who control the purse strings.

“There’s no longer time to meet the goal by 2020,” said Michael A’Hearn, a University of Maryland astronomer and co-author of the report. “There’s no way to do the survey in that length of time because the equipment isn’t even built yet. We say it is not unreasonable to set a new deadline of 2030 and start funding now. We probably can do the job by then.”

Despite the large number of NEO discoveries over the past several years, our current detection instruments like the Catalina Sky Survey, are not up to the task of completing the Congressional mandate, known as the George E. Brown Survey.

“The current instruments, no matter how you operate them are not capable of doing the George Brown survey,” A’Hearn noted.

And that’s to say nothing of the smaller asteroids, those in the 30- and 50-meter (90 to 165 foot) range, which hit Earth far more often than larger objects. Finding and tracking those little guys will require new telescopes like the Large Synoptic Sky Survey and Panstarrs, neither of which currently has the funding to complete construction.

Scientists have increasingly come to understand that the risk of asteroids and comets hitting Earth is real, but quantifying the risk that humans face from such events is much trickier.

“Our estimates of the risk could easily be wrong by a factor of two or three,” A’Hearn said. “I don’t think they are wrong by a factor of 10, but the boundaries, again, haven’t been explored.”

Even the Tunguska asteroid, which exploded over Siberia in 1908, remains something of a mystery. It’s unclear even how large the object was, A’Hearn said, which makes it difficult to know how common such an impact is. The rareness of the event makes it very tough to compare the risk from an asteroid strike with that from automobile collisions or other prosaic problems.

Right now, National Research Council scientists estimate the risk of being killed by an NEO impact is comparable to the risk of being one of the 50 or so people who die on an amusement park ride each year. The difference is that a major asteroid would kill many people all at once.

Another area of high uncertainty is the physics of asteroid impacts. Near-Earth objects of different types may require different mitigation strategies.

“The first thing we need to do is understand what the hazard is,” A’Hearn said. “That’s partly finding them and partly understanding what their effect is. We have to understand in more detail how we’d mitigate against them.”

Former astronaut Rusty Schweickart, a tireless campaigner for asteroid risk awareness, said the latest report was the best of its kind, surpassing an earlier NASA report to Congress on near-Earth object risk.

“I can certainly say that Irwin Shapiro, who I know very well personally, did a terrific job in putting this review together,” Schweickart said.

Lindley Johnson, program executive at NASA’s Near Earth Object Program, which wrote the NASA report agreed.

“It looks to be a very good report,” Johnson said. “It had a very strong team of top scientists in the area on the committee. They had the right people and it looks like they looked at all the right things.”

Differences begin to emerge between people who study near-Earth objects when mitigation options come up. The new report looks at two main ways of deflecting asteroids, following previous reports. First, the asteroid could be hit with some kind of impactor, either conventional or nuclear. Second, a longer-term, more precise technique like a gravity tractor could be employed.

Schweickart argued, however, that a gravity tractor, which would slowly push an asteroid off a collision path with Earth, should be considered a necessary but not independent part of any Earth defense.

“It’s the icing on the cake of stronger deflection needs,” Schweickart said. “It’s not comparable to and should never be considered the primary means of deflection.”

Update 1/25: Typos corrected to include the correct names for the George E. Brown Survey and the National Research Council report.

Image: U.S. Geological Survey/Composite: Tim Warchocki