NEO CONFERENCE - Rusty Schweickart

Rusty Schweickart, founder of the B612 Foundation and member of the Association of Space Explorers (ASE), introduced the problem of near Earth objects, focusing his talk mainly on what they are and how we might respond to them from a technological point of view. He concluded his presentation by also introducing the geopolitical issues involved. ASE, whose membership is limited to those who have actually traveled into space, focuses on the geopolitical, legal and decision-making issues related to NEOs. The B612 Foundation, meanwhile, focuses on the technologies related to NEO deflection.

Rusty described the number and distribution of NEOs. There are about 100,000 NEOs greater that 140 meters, and about 1,000 NEOs greater than one kilometer. These are statistical derivations, but close to actual observations - observations suggest that the statistical numbers are higher than actual. So far, NASA's Spaceguard has discovered about 82 percent of the latter group of NEOs (one km or larger). NASA has recently been directed to identify 90 percent of NEOs 140 meters and larger by 2020. It will probably not be able to make this goal due to various issues, but the effort is still important because it will contribute greatly to the database. Still, it is important to realize that 40-45 meter objects make major impact events, but telescopes are not capable of finding most of these until it is too late. There are about 1 million such objects and are not easily tracked. Tunguska was about 3-5 megatons, and fit into this category of "small" NEOs. Such an impact could devastate a large modern city.

There are three issues to address when it comes to NEOs: 1) What is out there? 2) How do we deal with the from a technological point of view, and 3) How do we decide to deal with them?

The NASA Spaceguard survey deals with #1. However, it needs to be made more robust in order to handle NEOs one kilometer and smaller. So far, there are 6,212 NEOs cataloged (as of April 22) and about 857 one kilometer and larger. Those with a non-zero probability of impact with Earth: ~246. This means that 246 NEOs may impact Earth at some point. The numbers change daily as data comes in. The survey needs to be better, and huge improvements are expected in terms of numbers by 2020 as telescopes come on line due to new NASA mandate.

The B612 Foundation and others are working on #2. Kinetic impact, or hitting the asteroid, constitutes a primary deflection capability. A gravity tractor can then "fine tune" such a deflection (secondary deflection). A nuclear missile can theoretically be used to superheat on side of a NEO that comes dangerously close to Earth in an effort to deflect the object. The secondary deflection also serves to ensure that the NEO does not pass through a "keyhole", which are gravitationally defined slots that define an orbit in which the NEO will impact Earth at some point in the future.

According to Rusty, “we currently depend on probabilities, since we do not have accurate measurements. The result is early warning is vague and uncertain.” Orbits, he said, we tend to know very well. Where the asteroid is in that orbit, however, is not always known accurately.

Finally #3 deals with the geopolitical matter of deflection decision, disaster mitigation and management. Details on this is discussed later in the conference. Questions include: How do we decide to deal with NEOs? How do we manage disasters when we miss a NEO? Which way to deflect? Who spends the money? How to ensure fast decision? These are reasons for working with the United Nations, which has existing fora to discuss these matters.

Rusty bottom lined it like this: "We currently have one eye open when it comes to detecting and tracking NEOs. The easiest thing to do is to close both eyes. It's also the cheapest. Procrastinating on a decision is tantamount to closing both eyes. Today, the effort is to open the other eye - to have both eyes open.”