For those who don't know, the B612 Foundation "consists of a group of professionals, primarily scientists and other technical experts, who are involved in and concerned about the current lack of action to protect the Earth from the impact of near Earth objects (NEOs)."
They recently have had a discussion with NASA about the asteroid Apophis, concerning the future close fly-by's of this asteroid and the need to take it seriously enough to begin planning for not just a scientific/transponder mission to Apophis, but also a mitigation/deflection mission. In October 2005, NASA provided its formal response to B612 in a letter from Dr. Mary Cleave, Associate Administrator for Science Mission Directorate, and an appended detailed analysis by Dr. Steven Chesley (NASA/JPL).
The entire letter can be found at the following link here, but I will list the main points from the article.
In summary NASA's conclusions are:
1) Both a deflection mission (of the type required for Apophis) and a scientific/transponder mission to Apophis can be performed sequentially, if required, between the key radar apparition in 2013 and the Earth close approach in 2029. There is therefore no need for a scientific/transponder mission to refine the Apophis orbit at this time.
Note: B612 assumed that 10-12 years would be required (end to end) to plan and execute the first asteroid deflection mission. NASA's 7 year estimate allows a potential pre-deflection transponder mission to be delayed until after the anticipated 2013 radar acquisition.
2) In 2021 when a deflection decision would have to be made, the size of the 2029 error ellipse (even without a transponder mission) will yield a maximum impact probability of about 20% (one chance in five), sufficient to justify launching a deflection mission if required.
Note: NASA agrees with B612 that a precursor transponder mission is appropriate prior to mounting a deflection mission. Nevertheless NASA also concludes that by the time a deflection decision would have to be made in 2021, the error ellipse will have been reduced sufficient to yield a maximum impact probability of 20%, twice the required minimum assumed by B612. This conclusion assumes that the Arecibo radar will be available and successfully acquire Apophis at each opportunity through 2021.
NASA also states that these conclusions do not preclude scientific missions to Apophis at an earlier time, and that in fact the specific characteristics of the 2029 Apophis encounter provide a unique opportunity to investigate NEOs. Any such proposals would be handled via the existing Discovery program, according to NASA.
The tone of NASA and JPLS's response leads me to believe that the issue concerning future impacts has now gone from a fringe concern to a mid-level detail. Their comments seem to call for even bolder action than what the B612 Foundation was proposing, for instance sending a deflection mission at the 2029 encounter instead of simply tracking it at that time. Considering the agreed impact percentage for 2029 is around 20%, they quite accurately state that this will be "sufficient to justify launching a deflection mission if required".
That's the good news. Now for the bad news.
B612 observations and general comments:
1) Radar tracking plays an extremely important role in being able to rationally determine the future likelihood of a NEO impact and potentially in planning for a deflection mission when required (as evident in the Chesley analysis). Yet the availability of NEO radar capability in the future is highly uncertain, even precarious. This is especially true of the most valuable NEO radar facility, Arecibo.
For those who are unaware, ARECIBO is the enormous Radar observatory located in Puerto Rico. The huge "dish" is 305 m (1000 feet) in diameter, 167 feet deep, and covers an area of about twenty acres. The surface is made of almost 40,000 perforated aluminum panels, each measuring about 3 feet by 6 feet, supported by a network of steel cables strung across the underlying karst sinkhole. The funding for Arecibo is currently back to full operational mode, thanks to Cornell University, but there was time that Arecibo was in danger of being shut down due to the fact that NASA was not willing to be the only one funding the operation any longer. Back in 2001 the story was- NASA Trims Arecibo Budget, Says Other Organizations Should Support Asteroid Watch. The B612 Foundation rightly points out that the availability of NEO radar capability in the future is highly uncertain, and this is a big problem.
2) The Apophis potential impact is a highly unusual, even unique case. Due to its close encounter with the Earth in April 2029, and its Earth-like orbit, a relatively inexpensive low-technology deflection technique will suffice to divert it from an Earth impact in 2036, should that condition eventuate.
3) In the typical NEO impact scenario however, a much more sophisticated, costly and advanced technology mission would be required. Moreover, a low cost, quick mission to place a transponder on such an object would not be a viable option. Apophis is not typical of the NEO impact threat and should not be seen as such.
Meaning, we won't need to completely turn this one around, possibly just nudge it a little. But this is not going to be the standard by any means for future NEO's.
4) All parties to this exchange of ideas acknowledge having learned a great deal in the process of working through the issues. However, absent B612 Foundation raising the question, the current understanding of the Apophis circumstances might not have developed. This is not an acceptable scenario. If instead, a specific US Government agency were assigned the responsibility of protecting the Earth from catastrophic NEO impacts, that agency would perform such an analysis as a routine matter for all potential NEO impactors.
There is no good reason whatsoever to fund future Space Exploration without solving the mitigation and detection of NEO's first. That it took the B612 Foundation to finally push NASA to start getting serious about it is a problem.
B612 Foundation therefore recommends:
1) That reliable NEO radar capability be assured in order to support early warning of pending NEO impacts and rational deflection mission planning. (National Science Foundation)
2) That the development of advanced space power and propulsion technology capable of providing access to and deflection of the general NEO population be initiated. (NASA)
3) That the responsibility for protection of the Earth from future NEO impacts be assigned to a capable US Government agency. Such responsibility should include, inter alia, early warning capability, deflection capability and related policy development authority. (US Government)
I realize that a Flu-pandemic is a bigger more pressing issue than NEO deflection in terms of large scale potential disasters. And it is far more likely that the human race will have to deal with a pandemic or a major terrorist strike before it will have to deal with a potential NEO impact. But this is no reason not to begin preparing for it.
As has been stated before, everyone who knew even a little bit about Hurricanes and New Orleans knew that it was only a matter of time until one inflicted the type of devastation we saw with Katrina. We have the same understanding of NEO's.
Evidence like this-
Barringer Meteorite Crater:Diameter (km): 1.186- Click Here for Barringer Crater Environmental Effects Page
One would hope that we have learned our lesson from Katrina. The present Bush administrations efforts to prepare for the possibility of a Pandemic are good signs. We need to take the same approach with NEO's, and Apophis is as good a target as any with which to begin.