Space Debris Clean Up and the Tragedy of the Commons
Space debris over 10cm in size have the potential to disintegrate entire space crafts, and more than 29,000 of these objects are currently in low Earth orbit. These objects pose a threat to the satellites within this orbit, essential for daily earth life, as well as spacecrafts traveling within range. While both national and private space agencies have reason to reduce the amount of space debris in in orbit, none have taken any significant steps to bring about a solution. The problem is that the removal of such debris is costly, and therefore companies are better off waiting for another group to go and reduce debris to reduce the risk to their own satellites. By waiting, these companies are able to reap the benefit of the costly debris reduction without having to pay the expenses. In turn, with all companies currently taking this position, none of the debris has been removed, allowing the threatening debris to remain.
The amount of space debris is only increasing as a result of aging space machinery and used rocket launchers deteriorating in space. Left unchecked, the threat of Kessler syndrome looms over head. Kessler syndrome is the catastrophic cascade of collisions which would arise from excessive amounts of space debris resulting in the widespread destruction of space machinery.
In this situation, each actor is making the decision to not remove debris based on what will be optimal for themselves, not taking the total welfare of the group into consideration. The result of this selfish acting within a public system is known as the “tragedy of the commons”. In the class lecture, the principle of this tragedy was explained as farmers who would have their cows graze in the commons, with no regard for the common welfare, until the land had been overgrazed, leaving no more area for grazing. This lack of ability to graze would result in unusable land and a suffering cow/farmer population. Similarly, through acting selfishly, space companies are steadily pushing all machinery in orbit towards a tragedy, with the public area becoming unusable by anyone, (Kessler syndrome). In both cases, the actors are making decisions logically and rationally with the given parameters, yet just as in the prisoner’s dilemma, this rational decision making does not always lead to beneficial cooperative behavior.
In the cow scenario, ownership was the remedy to this “tragedy of the commons”; a similar solution is being proposed by Karl Tuys and University of Liverpool researchers. They plan to use a computer model of debris removal to assess how much cooperation each entity involved would be willing to invest, given the immediate and long-term threat posed by debris to their assets. Tuys and his team have suggested entities could remove one piece of debris per year, or a proportional amount to their number of satellites in space. The enforcement of this suggestion would be similar to the ownership of the commons. To make the removal of debris in the entities’ best interest, the implementation of taxes or fines as a result of non-removal provide incentive to remove debris, thus prompting action, causing the whole to benefit and continue to function. The implementation of a monetary punishment for inaction creates the effect of ownership in that the “owning entity” (in the space scenario this is the body of international law enforcing taxation) creates conditions which make the prevention of the tragedy, or Kessler syndrome, in the best interest of actors making decisions rationally, thus resulting in the benefit of the common welfare.
http://phys.org/news/2015-11-space-debris-game-theory.html
http://phys.org/news/2015-10-game-theory-experts-analyse-space.html
http://www.nasa.gov/directorates/spacetech/niac/gregory_space_debris_elimination.html