• Ivan Bekey

As the size and longevity of spacecraft increase, so do the hazards posed by orbital debris. Various models have attempted to predict the future debris population and the effects of impacts with spacecraft. The hazard is taken seriously enough that an international dialogue is taking place on how to limit future production of debris. In addition, several new spacecraft, including the international space station ( ISS) and the Teledesic system, are taking defensive measures to minimize damage from such impacts. In the case of the ISS, this includes shielding the inhabited modules, a measure that is expensive, increases system weight, and adds to station launch costs.

A recent NASA study sought to determine the feasibility of removing the threat to low-altitude spacecraft by deorbiting nearly all debris objects of primary concern. This would be accomplished by irradiating the objects with a ground laser, which would ablate a thin surface layer of the debris and cause plasma blowoff. The resulting dynamic reaction would change the object's orbit, decreasing its perigee and causing its rapid reentry. The study, called Orion after the mythological archer, was cosponsored by the USAF Space Command, directed by the author (then at NASA Headquarters), and managed by John Campbell of NASA-Marshall.