Space Debris and Other Threats From Outer Space (10 page)

The most difficult area of all is with regard to the highly distributed millions of digital processors in automobiles, aircraft, appliances, etc., all over the world that could be zapped by a massive solar storm.

To cope with this level of threat would require a whole new mindset in design all over the world. This would involve changing basic designs so that digital processors would be backed up by mechanical systems that would in case of emergency back up the billions of processors and electrical systems that now permeate our daily lives. This is really not likely to happen unless there was a massive disaster in which billions of vehicles, aircraft and devices across the world were to be suddenly disabled. Short of this there could be underground parking garages and protective hangars and bunkers where critical aircraft and vehicles for national defense and other strategic purposes might be stored.

There was in the past perhaps only a day to day and half warning of such a pending disaster, since such a solar event would be seen within eight minutes of its occurrence. The highly charged particles even traveling at 4 million miles/hour (6.4 million km/hour) would take about 22 h to reach Earth. With the new information captured by the ACE, SOHO, and Stereo satellites, however, it is now possible to develop predictive information that can lead to as much as a three-day warning of a truly major CME event.

The problem that still remains is to convince the public and especially key governments to prepare for such a super solar storm—one of enormous intensity that may occur only once in hundreds of years. If virtually all of the world’s electrical grids, automobiles, aircraft, computers and electrical devices were to suddenly shut down, the world would in a matter of hours be virtually reduced back to the Stone Age.

There are several logical steps to be taken. First a concerted effort should be undertaken to ensure that Earth-based global solar monitoring systems and satellites serving this same purpose are sufficiently connected to global alert systems. Second a process should be begun to explore whether there are enough “solar flare-proof” buildings or underground facilities to at least protect critical aircraft, vehicles, telecommunications switches, or electrical grid transformers. In the case of above ground electrical transformers Faraday cages might systematically be built as protective structures. Third national legislatures might move to set safety standards for protection of electrical grids, telecommunications networks and other critical infrastructure.

In this discussion of legislatively mandated standards (or perhaps commercially developed safety protection standards) there might be additional provisions for heavy duty circuit breakers. There could be emergency alert systems that could allow powering down of electrical systems in the case of a super solar flare. It is not likely that cars or aircraft will in the future be built without processors, but perhaps there could be standards offered that allow for their better protection. Consumers might at least be offered options for automobiles with higher levels of “rad and ion hard” protection, and aircraft manufacturers could offer increased levels of protection as well.

6. We need a much better understanding of the hazards of radiation, particularly in an era with a diminishing protective ozone layer
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The greatest danger to spacecraft as well as to ground-based electrical grids, telecommunications networks and even pipeline lines clearly is posed by high energy coronal mass ejections or possibly even an orbital nuclear explosion that would give rise to an electro-magnetic pulse, but there are other serious threats from solar and cosmic sources. Super-charged X-ray gamma rays that come from the Sun and cosmic sources pack quite a wallop. The Van Allen belts and the ozone layer serve to screen out all but the most energetic of these radiations. The ozone holes in the polar regions allows the ultraviolet rays to penetrate through and constitute a threat in terms of not only elevated cancer risk but also greater risk of genetic mutation.

Gamma and high energy X-rays have been correlated to elevated skin cancer levels in humans in high latitude countries and to mutations in amphibians. These dangers are currently contained to areas with relatively low levels of habitation, but there are concerns that if the ozone holes should continue to expand that these risks could spread to an ever-larger geographic area. Although cancer is clearly a major danger, the spread of genetic mutations to humans over an expanded area could be a substantial threat to the entire human species.

7. Potentially hazardous NEOs pose a creditable threat. A large enough body colliding with Earth could result in a mass extinction of humankind and much of the animal and plant life on planet Earth
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Sixty-five million years is a long time for a species that has existed only a few million years. The so-called K-T mass-extinction event eliminated 65–70 % of the species on Planet Earth, and we know that if the planet today were to be hit by an asteroid of comparable size that it really would knock Earth back to the Stone Age and take out billions of people in the process. This is not to suggest that humans should live in fear of a possible event that may never come, or if it did, might be millions of years in the future.

Problems of a solar coronal mass ejection, solar energetic particles or cosmic radiation are in fact much more likely to occur on a cosmic time scale and could certainly be destructive on a similar scale. The Carrington event, for instance, was about 150 years ago versus the K-T event, which occurred 65 million years ago. Nevertheless, there are clearly a number of logical steps that could and should be taken.

Step number one is to develop a much clearer and more precise way of communicating with the general public on possible threats that might come from potentially hazardous asteroids or other cosmic bodies. The Torino Scale that was adopted at the international Unispace Conference provides a clear representation of threat levels from 1 to 10 that the public can easily understand and appropriately respond to if and when a possible threat is identified. It would be hoped that most potential threats would be at a threat level of under three and thus put into proper perspective. What is needed is more public education to let people and school children know that there are possible future threats and to learn not only the Richter Scale or the relative sizes of hurricanes or tornadoes but also the Torino scale.

The second step is to complete with the right astronomical observations from the ground and from space-sensing satellites an inventory of NEOs. The WISE (Wide-field Infrared Space Explorer) has provided valuable information—as has ground-based observations—but much more needs to be done to identify with some certainty that all potential risks have been cataloged. Surely we are smarter than the dinosaurs and can allocate needed resources to completing the inventory in coming years and to carry out these tasks by allocating only a modest amount of our space research budgets for this purpose.

The third step is to investigate better strategies for diverting a potentially harmful NEO from its orbit so as to avoid collision with Earth and to make sure that such diversion does not create a future hazard.

Clearly the top priority is to identify NEOs that are larger than 1,000 meters in size. This task, which is the easiest to undertake and serves to identify the largest threats, is essentially complete. As far as we know any potential collisions from NEOs of this size are hundreds of years in the future. But there is legitimate concern about NEOs that are sized in the 100–1,000 m range. Here, more systematic observation needs to be completed since only about 20% of those objects in the the 100–1,000 m range are estimated to have been detected.

The sensing capabilities of the WISE has accomplished a great deal in this respect, even though it was designed to detect much more distant cosmic objects through their infrared signature. Unfortunately the WISE satellite has now shut down since it can no longer function properly. In order to complete the inventory of these smaller NEOs one would need a WISE-type satellite with higher resolution and the ability to shift from wide range to narrow range focus on command and for this satellite to be essentially devoted to potentially harmful asteroid (PHA) detection.

Clearly the larger class of asteroid (i.e., those above 1,000 meters in diameter) would do much greater harm, but a 250 to 600 meter class PHA such as Apophis, if it were to hit Earth, could have the impact of tens of thousands of atomoic bombs. In short there are many more of the smaller class potentially hazardous asteroids out there, and an estimated 80 % of them are still undetected. Only one of these would still do enormous harm.

Finally, it would be useful not only to know the orbits of these satellites but to know their shape and composition in case it became necessary to seek to divert them from a collision with Earth.

9. What are the best strategies of coping with a potentially hazardous asteroid or other dangerous cosmic body that threatens Planet Earth
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There are studies and programs now under way to seek solutions to the problem of potentially hazardous asteroids. These activities can be generally sorted into the following areas: (i) Finding those potentially hazardous asteroids and comets that could most likely intersect with Earth orbit. This means not only those PHAs above the 1,000 m in diameter but also those in the range of 100–1,000 m that still remain 80 % unidentified. The NEO-WISE project has borne many results, but new space capabilities are needed to complete the task. (ii) Exploring the best strategies that could be employed to divert a PHA from Earth impact in terms of effectiveness and cost efficiency. Projects such as Earth Guard and NEOShield are often well conceived but are seriously underfunded. The identification of threats at the earliest possible time is key, because corrective action is most effective when carried out at as soon as possible; (iii) The final step is public education as well as that of legislators and government officials to help achieve an better understanding the various levels of threats from near-Earth objects.

The true key forward is an international space initiative that combines all of the resources of the world’s space agencies to address space-related threats. There has already been good international progress made by the Inter-Agency Space Debris Coordination Committee (IADC), the U. N. Committee on the Peaceful Uses of Outer Space (COPUOS) and even the Space Data Association (SDA), but this effort is largely concentrated on the issue of coping with space debris and the launch of nuclear power sources into space. This effort needs to be expanded as part of the COPUOS new initiative on the “Long Term Sustainability of Space” [35]. There should be a clear global plan forward that addresses potentially hazardous NEOs, the cracks in Earth’s geomagnetic shield, protection from the Sun’s radiation, coronal mass ejections and solar energetic particles. “This would a global initiative to undertake a systematic planetary defense that can save the human species from extinction. Let's prove we are smarter than the dinosaurs.”

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